Manual Well Plan

Using WELLPLAN R2003.11.0.1 copyright © 2004 by Landmark Graphics Corporation

Part No. 162163, Rev. A, V2003.11

August 2004

© 2001, 2002, 2003, 2004 Landmark Graphics Corporation All Rights Reserved Worldwide This publication has been provided pursuant to an agreement containing restrictions on its use. The publication is also protected by Federal copyright law. No part of this publication may be copied or distributed, transmitted, transcribed, stored in a retrieval system, or translated into any human or computer language, in any form or by any means, electronic, magnetic, manual, or otherwise, or disclosed to third parties without the express written permission of: Landmark Graphics Corporation Building 1, Suite 200, 2101 CityWest, Houston, Texas 77042, USA P.O. Box 42806, Houston, Texas 77242, USA Phone:713-839-2000 Help desk: 713-839-2200 FAX: 713-839-2401 Internet: www.lgc.com Trademark Notice 3DFS, 3D Drill View, 3D Drill View KM, 3DView, 3D Surveillance, Active Field Surveillance, Active Reservoir Surveillance, ADC, Advanced Data Transfer, ARIES, Asset Development Center, Asset Development Centre, Asset Performance, AssetView, Atomic Meshing, BLITZ, BLITZPAK, CasingSeat, COMPASS, Corporate Data Archiver, Corporate Data Store, Data Manager, DataStar, DBPlot, Decision Suite, Decisionarium, DecisionSpace, DecisionSpace AssetPlanner, DecisionSpace AssetView, DecisionSpace Atomic Meshing, DecisionSpace Decision Management Systems(DMS), DecisionSpace PowerGrid, DecisionSpace PowerModel, DecisionSpace PrecisionTarget, DecisionSpace Reservoir, DecisionSpace TracPlanner, DecisionSpace Well Seismic Fusion, DepthTeam, DepthTeam Explorer, DepthTeam Express, DepthTeam Express3, DepthTeam Extreme, DepthTeam Interpreter, Desktop Navigator, DESKTOP-PVT, DESKTOP-VIP, DEX, DFW, DIMS, Discovery, Discovery Asset, Drill-to-the-Earth Model, Drillability Suite, Drilling Desktop, DrillModel, DSS, Dynamic Reservoir Management, Dynamic Surveillance System, EarthCube, EDM, eLandmark, Engineer’s Data Model, Engineer's Desktop, Engineer’s Link, EOS-PAK, Executive Assistant, ezFault, ezSurface, ezTracker, FastTrack, FieldWorks, FZAP!, GeoDataLoad, GeoGraphix (stylized), GeoGraphix Exploration System, GeoLink, GeoProbe, GeoProbe GF DataServer, GeoProbe Integrated, GES, GESXplorer, GMAplus, GRIDGENR, Handheld Field Operator, I2 Enterprise, iDIMS, IsoMap, Landmark, Landmark and Design, Landmark logo and Design, Landmark Decision Center, LandScape, Lattix, LeaseMap, LMK Resources, LogEdit, LogM, LogPrep, Magic Earth, MagicDesk, MagicStation, MagicVision, Make Great Decisions, MathPack, MIRA, Model Builder, MyLandmark, OpenBooks, OpenExplorer, OpenJournal, OpenSGM, OpenVision, OpenWells, OpenWire, OpenWorks, OpenWorks Well File, PAL, Parallel-VIP, PetroBank, PetroWorks, PlotView, Point Gridding Plus, Pointing Dispatcher, PostStack, PostStack ESP, PowerCalculator, PowerExplorer, PowerHub, Power Interpretation, PowerJournal, PowerModel, PowerSection, PowerView, PRIZM, PROFILE, ProMAGIC, ProMAX, ProMAX 2D, ProMAX 3D, ProMAX 3DPSDM, ProMAX MVA, ProMAX VSP, pSTAx, QUICKDIF, QUIKCDP, QUIKDIG, QUIKRAY, QUIKSHOT, QUIKVSP, RAVE, RAYMAP, RTOC, Real Freedom, Real-Time Asset Management Center, Real-Time Asset Management Centre, Real Time Knowledge Company, Real-Time Operations Center, Real Time Production Surveillance, Real Time Surveillance, RESev, ResMap, RMS, SafeStart, SCAN, SeisCube, SeisMap, SeisModel, SeisSpace, SeisVision, SeisWell, SeisWorks, SeisXchange, Sierra, Sierra (design), SigmaView, SimResults, SIVA, Spatializer, SpecDecomp, StrataAmp, StrataMap, Stratamodel, StrataSim, StratWorks, StressCheck, STRUCT, Surf & Connect, SynTool, System Start for Servers, SystemStart, SystemStart for Clients, SystemStart for Storage, T2B, TDQ, Team Workspace, TERAS, Total Drilling Performance, TOW/cs, TOW/cs The Oilfield Workstation, TracPlanner, Trend Form Gridding, Turbo Synthetics, VIP, VIP-COMP, VIP-CORE, VIP-DUAL, VIP-ENCORE, VIP-EXECUTIVE, VIP-Local Grid Refinement, VIP-THERM, WavX, Web Editor, Web OpenWorks, Well Seismic Fusion, Wellbase, Wellbore Planner, Wellbore Planner Connect, WELLCAT, WELLPLAN, WellXchange, WOW, Xsection, You're in Control. Experience the difference, ZAP!, and Z-MAP Plus are trademarks, registered trademarks or service marks of Landmark Graphics Corporation or Magic Earth, Inc. Note The information contained in this document is subject to change without notice and should not be construed as a commitment by Landmark Graphics Corporation. Landmark Graphics Corporation assumes no responsibility for any error that may appear in this manual. Some states or jurisdictions do not allow disclaimer of expressed or implied warranties in certain transactions; therefore, this statement may not apply to you.

Contacting Support Landmark operates Technical Assistance Centers (TACs) in Houston, Texas, Leatherhead, UK and Perth, Australia. Additional support is provided through district support offices around the world. If problems cannot be resolved at the district level, our escalation team is called to resolve your incidents quickly. Support information is always available on the Landmark Graphics Support internet page located at:- http:\\www.lgc.com\customersupport. Technical Assistance Centers North America 7:30 am - 5:30 pm Central Standard Time Monday - Friday, excluding holidays

713-839-2200 (Houston, TX, USA) Toll Free 1-877-435-7542 (1-877-HELP-LGC) Fax: 713-839-2168 (Houston, TX) Fax: 512-292-2200, 2220 (Austin, TX) Fax: 907-275-2655 (Anchorage, AK) Fax: 303-796-0807 (Denver, CO) Fax: 403-262-1929 (Calgary, Canada) Email: [email protected]

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Vietnam (Ho Chi Minh City) 8:00 am - 5:00 pm Local Time Monday - Friday, excluding holidays


Helpful internet links are shown below. Name

Website Address

Landmark Graphics home page

http://www.lgc.com

Landmark Graphics FTP Site

ftp://ftp.lgc.com

Oracle home page

http://www.oracle.com

FLEXlm license management software home page

http://www.macrovision.com/products/ legacy_products/flexlm/index.html

Microsoft SQL Server home page

http://www.microsoft.com/sql/default.asp

Adobe Acrobat Reader

http://www.adobe.com

Microsoft MSDE

http://www.microsoft.com/sql/default.asp

Landmark

WELLPLAN Training Manual

Contents Contacting Support .............................................................................................................

3

Introduction .......................................................................................................................

25 25 25 26

What is WELLPLAN? ................................................................................................. Training Course and Manual Overview ....................................................................... Licensing ................................................................................................................

The Engineer’s Data Model (EDM) Database .................................................. Overview............................................................................................................................. Logging In To the Database................................................................................................ Starting WELLPLAN .................................................................................................. Describing the Data Structure............................................................................................. Associated Components ............................................................................................... Associated with Designs: ....................................................................................... Associated with Cases: .......................................................................................... Copying and Pasting Associated Items .................................................................. Rules for Associating Components ........................................................................ Common Data ..................................................................................................................... Data Locking....................................................................................................................... How Locking Works .............................................................................................. Simultaneous Activity Monitor (SAM) .............................................................................. Concurrent Use of Same Data By Multiple Users .............................................................. How the Well Explorer Handles Concurrent Users ..................................................... Same User on Same Computer .............................................................................. Multiple Users, Different Computers .................................................................... Reload Notification ...................................................................................................... Importing and Exporting Data ............................................................................................ Importing Data into the EDM Database ...................................................................... Importing EDM Well Data from Another Database .............................................. Importing a DEX File Into the Database ............................................................... Exporting Data From the EDM Database .................................................................... Exporting Data in XML Format ............................................................................ Exporting Well Data in DEX Format .................................................................... Using Datums in EDM ....................................................................................................... Definition of Terms Associated With Datums ............................................................ Project Properties ................................................................................................... Well Properties ...................................................................................................... Design Properties ................................................................................................... Setting Up Datums for Your Design ............................................................................ August 2004

Contents

27 27 28 28 29 32 32 33 33 34 35 36 36 38 39 39 40 40 40 42 42 42 43 45 45 46 48 48 48 48 50 50 ix


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Changing the Datum ....................................................................................................

51

Using the Well Explorer ..............................................................................................

55 55 56 57 57 57 60 60 60 61 61 62 63 64 64 65 66 66 66 67 68 68 68 68 68 69 70 70 70 70 71 71 74 74 75 76 76 76 76 77 77 77 77

Overview............................................................................................................................. Describing the Well Explorer ............................................................................................. Components of the Well Explorer ............................................................................... The Tree ................................................................................................................. Associated Data Components ................................................................................ The Recent Bar ............................................................................................................ Displaying/Hiding the Well Explorer and Recent Bar ................................................ Refreshing the Well Explorer ...................................................................................... Positioning the Well Explorer ...................................................................................... Tracking Data Modifications ....................................................................................... Drag and Drop Rules ................................................................................................... Well Explorer Right-Click Menus ............................................................................... Working at the Database Level .................................................................................... New Company (Database Level) ........................................................................... Instant Case (Database Level) ............................................................................... Export (Database Level) ........................................................................................ Import (Database Level) ........................................................................................ Properties (Database Level) ................................................................................... Well Name (Database Level) ................................................................................. Wellbore Name (Database Level) .......................................................................... Refresh (Database Level) ....................................................................................... Expand All (Database Level) ................................................................................. Collapse All (Database Level) ............................................................................... Working at the Company Level ................................................................................... New Project (Company Level) .............................................................................. New Attachment (Company Level) ....................................................................... Paste (Company Level) .......................................................................................... Rename (Company Level) ..................................................................................... Delete (Company Level) ........................................................................................ Export (Company Level) ....................................................................................... Properties (Company Level) .................................................................................. Expand All (Company Level) ................................................................................ Collapse All (Company Level) .............................................................................. Working at the Project Level ....................................................................................... New Site (Project Level) ........................................................................................ New Attachment (Project Level) ........................................................................... Copy (Project Level) .............................................................................................. Paste (Project Level) .............................................................................................. Rename (Project Level) ......................................................................................... Delete (Project Level) ............................................................................................ Export (Project Level) ........................................................................................... Properties (Project Level) ...................................................................................... x

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Expand All (Project Level) .................................................................................... 79 Collapse All (Project Level) .................................................................................. 79 Working at the Site Level ............................................................................................ 79 New Well (Site Level) ........................................................................................... 80 New Attachment (Site Level) ................................................................................ 81 Copy (Site Level) ................................................................................................... 81 Paste (Site Level) ................................................................................................... 81 Rename (Site Level) .............................................................................................. 81 Delete (Site Level) ................................................................................................. 81 Export (Site Level) ................................................................................................. 81 Properties (Site Level) ........................................................................................... 81 Expand All (Site Level) ......................................................................................... 84 Collapse All (Site Level) ....................................................................................... 84 Working at the Well Level ........................................................................................... 85 New Wellbore (Well Level) .................................................................................. 85 New Attachment (Well Level) ............................................................................... 86 Copy (Well Level) ................................................................................................. 86 Paste (Well Level) ................................................................................................. 86 Rename (Well Level) ............................................................................................. 86 Delete (Well Level) ............................................................................................... 87 Export (Well Level) ............................................................................................... 87 Properties (Well Level) .......................................................................................... 87 Expand All (Well Level) ........................................................................................ 92 Collapse All (Well Level) ...................................................................................... 92 Working at the Wellbore Level ................................................................................... 92 New Design (Wellbore Level) ............................................................................... 93 New Design/Case from OpenWells ....................................................................... 94 New Attachment (Wellbore Level) ........................................................................ 94 Cut (Wellbore Level) ............................................................................................. 94 Copy (Wellbore Level) .......................................................................................... 94 Paste (Wellbore Level) .......................................................................................... 94 Rename (Wellbore Level) ...................................................................................... 94 Delete (Wellbore Level) ........................................................................................ 95 Export (Wellbore Level) ........................................................................................ 95 Properties (Wellbore Level) ................................................................................... 95 Expand All (Wellbore Level) ................................................................................ 97 Collapse All (Wellbore Level) ............................................................................... 97 Working at the Design Level ....................................................................................... 98 New Case (Design Level) ...................................................................................... 98 New Attachment (Design Level) ........................................................................... 99 Copy (Design Level) .............................................................................................. 99 Paste (Design Level) .............................................................................................. 99 Rename (Design Level) ......................................................................................... 99 Delete (Design Level) ............................................................................................ 99 Export (Design Level) ........................................................................................... 99 Properties (Design Level) ...................................................................................... 100 August 2004

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Expand All (Design Level) .................................................................................... Collapse All (Design Level) .................................................................................. Working at the Case Level (WELLPLAN Only) ........................................................ Open (Case Level) ................................................................................................. Close (Case Level) ................................................................................................. Clear Active Workspace (Case Level) ................................................................... New Attachment (Case Level) ............................................................................... Copy (Case Level) ................................................................................................. Paste (Case Level) ................................................................................................. Rename (Case Level) ............................................................................................. Delete (Case Level) ............................................................................................... Export (Case Level) ............................................................................................... Properties (Case Level) .......................................................................................... Working With Design- and Case-Associated Components ......................................... About Associated Items and Well Explorer .......................................................... Working With Catalogs ............................................................................................... Creating a New Catalog ......................................................................................... Copying a Catalog ................................................................................................. Deleting a Catalog ................................................................................................. Exporting a Catalog ............................................................................................... Importing a Catalog ............................................................................................... Opening a Catalog ................................................................................................. Saving a Catalog .................................................................................................... Closing a Catalog ................................................................................................... Catalog Properties Dialog ......................................................................................

102 102 102 103 103 103 103 103 104 104 104 104 104 108 108 110 111 112 112 112 113 113 113 114 114

Concepts and Tools ...................................................................................................... 117 Overview............................................................................................................................. Accessing Online Documentation and Tools...................................................................... Using the Main Window..................................................................................................... Using the Well Explorer .............................................................................................. Using the Menu Bar ............................................................................................................ Working With Units............................................................................................................ Configuring Unit Systems ........................................................................................... Converting MD to TVD, or TVD to MD ..................................................................... Converting Field or Cell Units ..................................................................................... Defining Tubular Temperature Deration, Grade, Material and Class ................................ Temperature Deration .................................................................................................. Material ........................................................................................................................ Tubular Grades ............................................................................................................ Class ............................................................................................................................. Using Halliburton Cementing Tables ................................................................................. Configuring Sound Effects ................................................................................................. Using the Online Help ........................................................................................................ Using Tool Bars .................................................................................................................. xii

Contents

117 118 119 119 120 122 122 123 123 125 125 125 126 127 129 130 131 132

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Enabling Toolbars ........................................................................................................ Using the Standard Toolbar ......................................................................................... Using the Module Toolbar ........................................................................................... Using the Graphics Toolbar ......................................................................................... Using the Wizard Toolbar ............................................................................................ Using Wellpath Plots and Schematics ................................................................................ Using Well Schematics ................................................................................................ Viewing Wellpath Plots ............................................................................................... Accessing Wellpath Plots ............................................................................................ Printing and Print Preview .................................................................................................. Configuring Plot Properties ................................................................................................ Changing Curve Line Properties .................................................................................. Using Freeze Line .................................................................................................. Using the Plot Properties Tabs ..................................................................................... Accessing the Plot Properties Tabs ........................................................................ Changing the Scale ................................................................................................ Configuring the Axis ............................................................................................. Changing the Grid .................................................................................................. Changing the Axis Labels ...................................................................................... Changing the Font .................................................................................................. Changing the Line Styles ....................................................................................... Using Data Markers ............................................................................................... Configuring the Legend ......................................................................................... Changing the Plot Background Color .................................................................... Using Libraries ................................................................................................................... What is a Library? ........................................................................................................ Using String Libraries .................................................................................................. Creating or Deleting a String Library Entry .......................................................... Retrieving a String From the String Library .......................................................... Using Fluid Libraries ................................................................................................... Importing, Exporting, Deleting, and Renaming a Fluid Library Entry ................. Exporting a Library ...................................................................................................... Using Workspaces .............................................................................................................. What is a Workspace ................................................................................................... Applying a Workspace ................................................................................................. Configuring a User Workspace .................................................................................... Using a Window .................................................................................................... Using Window Panes ............................................................................................. Using Tabs ............................................................................................................. Saving the User Workspace Configuration ........................................................... Using Data Status Tooltips and Status Messages ............................................................... Configuring Tool Tips and Field Descriptions ...................................................................

132 133 133 134 134 135 135 136 136 137 138 138 139 140 140 141 141 142 143 143 144 145 146 147 148 148 148 148 149 150 150 151 152 152 152 153 153 154 155 157 158 159

Describing the Case Using the Case Menu ..................................................... 161 Overview............................................................................................................................. 161 August 2004

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Entering Case Data ............................................................................................................. Defining the Hole Section Geometry ........................................................................... Hole Section Editor Menu ..................................................................................... Defining a Work String ................................................................................................ Managing Wellpath Data ............................................................................................. Importing Wellpath Files ....................................................................................... Entering Wellpath Data ......................................................................................... Setting Wellpath Options ....................................................................................... Viewing Wellpaths w/Tortuosity ........................................................................... Viewing Wellpath w/Interpolation ........................................................................ Defining the Active Fluid and Fluid Properties ........................................................... Defining Drilling Fluids ......................................................................................... Specify Circulating System Equipment ....................................................................... Specifying Circulating System for Cementing Analysis ....................................... Specifying Pore Pressure Data ..................................................................................... Specifying Fracture Gradient Data .............................................................................. Specifying Geothermal Gradient Data ......................................................................... Defining String Eccentricity ........................................................................................

162 162 163 163 166 166 167 168 168 169 169 169 171 172 173 173 174 175

Torque Drag Analysis................................................................................................... 177 Overview............................................................................................................................. 177 Workflow ............................................................................................................................ 178 Introducing Torque Drag Analysis ..................................................................................... 181 Starting Torque Drag Analysis .................................................................................... 181 Available Analysis Modes ........................................................................................... 182 Defining the Case Data ....................................................................................................... 184 Defining Operating Parameters .......................................................................................... 185 Specifying Weight Indicator Corrections, Analytical Models and Reporting of Mechanical Limitations ................................................................................................................... 185 Enabling Sheave Friction Corrections ................................................................... 185 Why Use Bending Stress Magnification Factor? ................................................... 186 Why Use the Stiff String Model? .......................................................................... 186 Including Viscous Drag Calculations .................................................................... 187 Specifying Multiple Fluids or Surface Pressure .......................................................... 187 How does Fluid Flow Change the Forces and Stresses on the Workstring? ......... 188 How Does Surface Pressure Change the Forces And Stresses On the Workstring? 189 Using Standoff Devices ............................................................................................... 189 Calibrating Coefficients of Friction Using Field Data........................................................ 191 Starting the Calibrate Friction Analysis Mode ............................................................ 191 Recording Actual Load Data ....................................................................................... 192 Calibrating Coefficients of Friction ............................................................................. 192 Predicting Maximum Measured Weight and Torque ......................................................... 194 Starting Drag Chart Analysis ....................................................................................... 194 Defining Operating Conditions and the Analysis Depth Interval ................................ 194 Advanced Options .................................................................................................. 195 xiv

Contents

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Analyzing Drag Chart Results ..................................................................................... Tension Point Chart ............................................................................................... Torque Point Chart ................................................................................................. Using the Sensitivity Plot ...................................................................................... Analyzing Critical Measured Depths.................................................................................. Start Normal Analysis .................................................................................................. Defining Operating Conditions .................................................................................... Analyzing Normal Analysis Results ............................................................................ Analyzing Normal Analysis Results Using Plots .................................................. Using Tables to Analyze Results ........................................................................... Analyzing Results Using Reports .......................................................................... Analysis Mode Methodology.............................................................................................. Normal Analysis .......................................................................................................... Calibrate Friction Analysis .......................................................................................... Drag Chart Analysis ..................................................................................................... Top Down Analysis ..................................................................................................... Supporting Information and Calculations........................................................................... Additional Side Force Due to Buckling ....................................................................... Sinusoidal Buckling Mode ..................................................................................... Helical Buckling Mode .......................................................................................... Axial Force .................................................................................................................. Buoyancy Method .................................................................................................. Pressure Area Method ............................................................................................ Bending Stress Magnification (BSM) .......................................................................... Buoyed Weight ............................................................................................................ Critical Buckling Forces .............................................................................................. Straight Model Calculations .................................................................................. Curvilinear Model .................................................................................................. Loading and Unloading Models ............................................................................ Drag Force Calculations .............................................................................................. Fatigue Calculations .................................................................................................... Establish A Fatigue Endurance Limit For The Pipe .............................................. Derate The Fatigue Endurance Limit For Tension ................................................ Friction Factors ............................................................................................................ Models ......................................................................................................................... Pipe Wall Thickness Modification Due to Pipe Class ................................................. Sheave Friction ............................................................................................................ Side Force for Soft String Model ................................................................................. Soft String Model ......................................................................................................... Stiff String Model ........................................................................................................ Stress ............................................................................................................................ Von Mises Stress ................................................................................................... Radial Stress .......................................................................................................... Transverse Shear Stress ......................................................................................... Hoop Stress ............................................................................................................ Torsional Stress ...................................................................................................... August 2004

Contents

196 196 197 198 200 200 201 201 202 206 208 209 209 211 212 214 217 217 217 217 218 219 219 220 221 222 223 223 224 226 228 229 229 232 233 233 234 235 237 237 239 239 240 240 240 240 xv


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Bending Stress ....................................................................................................... Buckling Stress ...................................................................................................... Axial Stress ............................................................................................................ Stretch .......................................................................................................................... Stretch due to axial load ......................................................................................... Stretch due to buckling .......................................................................................... Stretch due to ballooning ....................................................................................... Tortuosity ..................................................................................................................... Torque .......................................................................................................................... Twist ............................................................................................................................ Viscous Drag ................................................................................................................ References........................................................................................................................... General ......................................................................................................................... Bending Stress Magnification Factor .......................................................................... Buckling ....................................................................................................................... Fatigue ......................................................................................................................... Sheave Friction ............................................................................................................ Side Force Calculations ............................................................................................... Stiff String Model ........................................................................................................

240 240 241 242 242 242 243 244 244 246 247 250 250 250 250 251 251 251 252

Hydraulics Analysis ...................................................................................................... 253 Overview............................................................................................................................. Workflow ............................................................................................................................ Introducing Hydraulic Analysis.......................................................................................... Starting Hydraulics Analysis ....................................................................................... Available Analysis Modes ........................................................................................... Defining the Case Data ....................................................................................................... Optimizing Bit Hydraulics.................................................................................................. Using Graphical Analysis Mode .................................................................................. Entering Pump Specifications ................................................................................ Analyzing Results .................................................................................................. Numerical Optimization .............................................................................................. Determining the Minimum Flow Rate................................................................................ Starting the Hole Cleaning Operational Analysis ........................................................ Entering Analysis Data ................................................................................................ Analyzing Results ........................................................................................................ Analyzing Results Using Plots .............................................................................. Analyzing Results Using the Operational Report .................................................. Determining the Maximum Flow Rate ............................................................................... Starting Annular Velocity Analysis Mode ................................................................... Defining Pump Rates ................................................................................................... Analyzing Results ........................................................................................................ Analyzing Results Using Plots .............................................................................. Analyzing Results Using Tables ............................................................................ Determining the Bit Nozzle Sizes....................................................................................... xvi

Contents

253 254 257 257 258 260 261 261 261 262 269 272 272 273 273 273 276 277 277 278 278 278 280 282

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Starting the Pressure: Pump Rate Range Analysis Mode ............................................ Defining the Pump Rate Range ................................................................................... Specifying the Nozzle Configuration .......................................................................... Specifying Depths to Calculated ECD ......................................................................... Analyzing Results ........................................................................................................ Using the Pressure Loss Plot ................................................................................. Using the Pressure Loss Report ............................................................................. Fine Tuning Hydraulics ...................................................................................................... Starting Pressure Pump Rate Fixed Analysis Mode .................................................... Defining the Pump Rate to Analyze ............................................................................ Analyzing Results ........................................................................................................ Analyzing Results Using Plots .............................................................................. Calculating a Tripping Schedule......................................................................................... Starting Swab/Surge Tripping Schedule Analysis ....................................................... Defining Analysis Constraints ..................................................................................... Analyzing Results ........................................................................................................ Using Reports to Analyze Results ......................................................................... Analyzing Pressures and ECDs While Tripping................................................................. Starting Swab/Surge Pressure and ECD Analysis Mode ............................................. Defining Operations Constraints ................................................................................. Analyzing Results ........................................................................................................ Using Plots to Analyze Results .............................................................................. Using Reports to Analyze Results ......................................................................... Supporting Information and Calculations........................................................................... Backreaming Rate (Maximum) Calculation ................................................................ Bingham Plastic Rheology Model ............................................................................... Bit Hydraulic Power .................................................................................................... Bit Pressure Loss Calculations .................................................................................... Derivations for PV, YP, 0-Sec Gel and Fann Data ...................................................... ECD Calculations ........................................................................................................ Graphical Analysis Calculations .................................................................................. Hole Cleaning Methodology and Calculations ............................................................ Bit Impact Force .......................................................................................................... Nozzle Velocity ........................................................................................................... Optimization Planning Calculations ............................................................................ Optimization Well Site Calculations ........................................................................... Power Law Rheology Model ....................................................................................... Pressure Loss Analysis Calculations ........................................................................... Pump Power Calculations ............................................................................................ Pump Pressure Calculations ......................................................................................... Shear Rate and Shear Stress Calculations .................................................................... Swab/Surge Calculations ............................................................................................. Tool Joint Pressure Loss Calculations ......................................................................... Weight Up Calculations ............................................................................................... References........................................................................................................................... General ......................................................................................................................... August 2004

Contents

282 282 284 285 285 286 287 288 288 288 289 289 293 293 293 294 294 296 296 296 297 297 298 300 300 300 304 305 305 306 307 307 314 315 315 316 319 324 325 326 326 327 329 330 331 331 xvii


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Bingham Plastic Model ................................................................................................ Coiled Tubing .............................................................................................................. Hole Cleaning .............................................................................................................. Herschel Bulkley Model .............................................................................................. Optimization Well Site ................................................................................................ Power Law Model ........................................................................................................ Rheology Thermal Effects ........................................................................................... Surge Swab .................................................................................................................. Tool Joint Pressure Loss ..............................................................................................

331 331 331 332 332 332 332 333 333

Well Control Analysis................................................................................................... 335 Overview............................................................................................................................. Workflow ............................................................................................................................ Introducing Well Control Analysis..................................................................................... Starting Well Control Analysis .................................................................................... Available Analysis Modes ........................................................................................... Defining the Case Data ....................................................................................................... Calculating the Expected Influx Volume............................................................................ Starting Expected Influx Volume Analysis Mode ....................................................... Specify Choke and Kill Line Use ................................................................................ Defining the Circulating Temperature Profile ............................................................. Determining the Type of Kick ..................................................................................... Estimating Influx Volume ........................................................................................... Analyzing Results ........................................................................................................ Influx Volume Estimation Results Tab ................................................................. Using Plots ............................................................................................................. Circulating the Kick............................................................................................................ Specifying Kill Method, and Choke/Kill Line Data .................................................... Specify Choke and Kill Line Data ......................................................................... Select Kill Method and Enter Operational Data .................................................... Specify Kill Rate and Kick Data .................................................................................. Analyzing Results ........................................................................................................ Using Plots ............................................................................................................. Animation .............................................................................................................. Generating a Kill Sheet....................................................................................................... Specify Kill Method, Operational Data, Slow Pumps and Choke/Kill Line Use ........ Specify Choke and Kill Line Data ......................................................................... Selecting Kill Method and Entering Operational Data .......................................... Specifying Slow Pump Data .................................................................................. Entering Kill Sheet Data .............................................................................................. Specifying Kick Analysis Parameters .................................................................... Analyzing Results ........................................................................................................ Plots ....................................................................................................................... Reports ................................................................................................................... Analysis Mode Methodology.............................................................................................. xviii

Contents

335 336 338 338 339 340 341 341 341 342 343 344 347 347 348 349 349 349 350 350 351 351 357 359 359 359 359 360 360 360 362 362 362 364

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General Assumptions and Terminology ...................................................................... Initial Influx Volume ............................................................................................. Influx Properties Assumptions ............................................................................... Influx Annular Volume and Height ....................................................................... Choke Pressure and Influx Position ....................................................................... Kill Methods .......................................................................................................... Expected Influx Volume .............................................................................................. Kick Tolerance ............................................................................................................. Kill Sheet ..................................................................................................................... Supporting Information and Calculations........................................................................... Allowable Kick Volume Calculations ......................................................................... Estimated Influx Volume and Flow Rate Calculations ............................................... Gas Compressibility ..................................................................................................... Influx Circulation Model for Kick While Drilling or After Pump Shutdown ............. Influx Circulation Model for Swab Kicks ................................................................... Kick Classification ....................................................................................................... Kick While Drilling ............................................................................................... Kick After Pump Shutdown ................................................................................... Swab Kick .............................................................................................................. Kick After Pump Shut Down Influx Estimation .......................................................... Kick While Drilling Influx Estimation ........................................................................ Kill Sheet ..................................................................................................................... Pressure at Depth of Interest ........................................................................................ Pressure Loss Analysis ................................................................................................ Steady State Circulation Temperature Model .............................................................. Viscosity and Compressibility of Methane .................................................................. References........................................................................................................................... General ......................................................................................................................... Estimated Influx Volume and Flow Rate .................................................................... Gas Compressibility (Z Factor) Model Calculations ................................................... Steady State Temperature ............................................................................................

364 364 364 365 365 365 366 367 371 372 372 372 373 376 380 385 385 386 386 386 389 392 396 396 397 400 403 403 403 403 403

Surge Analysis ................................................................................................................. 405 Overview............................................................................................................................. Workflow ............................................................................................................................ Introducing Surge Analysis ................................................................................................ What is the Surge Module? .......................................................................................... What is the Difference Between a Transient and Steady-State Model? ...................... When Should I use the Transient Surge Model? ......................................................... Starting Surge Analysis ............................................................................................... Defining the Case Data ....................................................................................................... Defining Formation Properties .................................................................................... Defining the Properties of the Set Cement .................................................................. Specifying Analysis Parameters Common to Surge, Swab, and Reciprocation Analysis .. Defining the Wellbore Fluids and Specifying Pump Rates ......................................... August 2004

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Using Standoff Devices ............................................................................................... Analyzing Surge and Swab Operations .............................................................................. Selecting the Surge/Swab Analysis Mode ................................................................... Defining Analysis Parameters ..................................................................................... Analyzing Surge and Swab Analysis Results ..................................................................... Analyzing Results Using Plots .................................................................................... Using Operation Plots ............................................................................................ Using the Miscellaneous Plots ............................................................................... Analyzing Results Using the Report ...................................................................... Analyzing Reciprocating Operations.................................................................................. Selecting the Reciprocation Analysis Mode ................................................................ Defining Analysis Parameters ..................................................................................... Analyzing Results ........................................................................................................ Analyzing Results Using Plots .............................................................................. Using Operation Plots ............................................................................................ Using the Miscellaneous Plots ............................................................................... Analyzing Results Using the Report ...................................................................... Supporting Information and Calculations........................................................................... Methodology ................................................................................................................ Pressure and Temperature Behavior of Water Based Muds ........................................ Viscosity Correlations of Oil Based Muds .................................................................. Surge Analysis ............................................................................................................. Two Analysis Regions ........................................................................................... Connecting the Coupled-Pipe/Annulus and the Pipe-to-Bottomhole Regions ...... Open Annulus Calculations ......................................................................................... Mass Balance ......................................................................................................... Momentum Balance ............................................................................................... Coupled Pipe Annulus Calculations ............................................................................ Pipe Flow ............................................................................................................... Annulus Flow ......................................................................................................... Pipe Motion ............................................................................................................ Closed Tolerance ......................................................................................................... References........................................................................................................................... Transient Pressure Surge ............................................................................................. Validation ..................................................................................................................... Pipe and Borehole Expansion ...................................................................................... Frictional Pressure Drop .............................................................................................. Pressure and Temperature Fluid Property Dependence ...............................................

415 416 416 417 418 418 418 424 426 427 427 428 428 429 429 436 438 439 439 439 440 440 440 443 444 444 444 445 445 446 446 447 453 453 453 453 453 454

Cementing-OptiCem Analysis ................................................................................. 455 Overview............................................................................................................................. Workflow ............................................................................................................................ Introducing Cementing Analysis ........................................................................................ What is Cementing? ..................................................................................................... Starting Cementing Analysis ....................................................................................... xx

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Defining the Case Data ....................................................................................................... Specify the Volume Excess % ..................................................................................... Defining the Cement Job .................................................................................................... Defining the Cement Job Fluids .................................................................................. Defining Spacers .................................................................................................... Defining Cement Slurries ...................................................................................... Specify the Standoff or Calculate the Centralizer Placement ...................................... Defining the Cement Job ............................................................................................. Defining Temperatures, Depths of Interest and Offshore Returns Information .......... Specifying Additional Analysis Parameters ................................................................ Analyzing Results ........................................................................................................ What is the Circulating Pressure Throughout the Cement Job? ............................ Is There Free Fall? ................................................................................................. What is the Surface Pressure? ................................................................................ Automatically Adjusting the Flowrate ................................................................... Using Foamed Cement ........................................................................................... References...........................................................................................................................

459 459 460 460 460 461 461 462 463 464 465 465 467 467 468 471 476

Critical Speed ................................................................................................................... 477 Critical Speed Course Overview......................................................................................... Workflow ............................................................................................................................ Introducing Critical Speed Analysis ................................................................................... What is the Critical Speed Module? ............................................................................ Why Use the Critical Speed Module? .......................................................................... Critical Speed Limitations ........................................................................................... Using Critical Speed ........................................................................................................... Starting the Critical Speed Module .............................................................................. Defining the Case Data ....................................................................................................... Determining Critical Rotational Speeds ............................................................................. Defining Analysis Parameters ..................................................................................... Specifying the Boundary Conditions ........................................................................... Specifying the Mesh Zone ........................................................................................... Analyzing the Results .................................................................................................. What are the Critical Rotational Speeds? .............................................................. Non-Converged Solutions ...................................................................................... Where in the BHA are the Large Relative Stresses Occurring? ............................ What Kind of Stress is Causing the Large Relative Stress? .................................. How Do I View the Large Relative Stress at Any Position on One Plot? ............. Supporting Information and Calculations........................................................................... Structural Solution ....................................................................................................... Vibrational Analysis .................................................................................................... Mass Matrix ................................................................................................................. Damping Matrix ........................................................................................................... Excitation Factors ........................................................................................................ References........................................................................................................................... August 2004

Contents

477 478 479 479 479 480 481 481 483 483 483 484 484 485 485 486 487 488 489 491 491 491 494 494 495 498 xxi


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Bottom Hole Assembly ............................................................................................... 499 Overview............................................................................................................................. Workflow ............................................................................................................................ Introducing Bottom Hole Assembly Analysis .................................................................... What is the Bottom Hole Assembly Module? ............................................................. Why Should I Use the Bottom Hole Assembly Module? ............................................ Bottom Hole Assembly Module Limitations ............................................................... Starting Bottom Hole Assembly Analysis ................................................................... Defining the Case Data ....................................................................................................... Analyzing a Static Bottom Hole Assembly ........................................................................ Defining Analysis Parameters for Static Analysis ....................................................... Drillahead Solution ................................................................................................ Specifying the Mesh Zone ........................................................................................... Analyzing Results for the Static (in-place) Position .................................................... Using the Quick Look Section of the BHA Analysis Data Dialog ........................ Using Plots ............................................................................................................. Using Predicted Plots ............................................................................................. Using the BHA Report ........................................................................................... Predicting How a Bottom Hole Assembly Will Drill Ahead.............................................. Defining Analysis Parameters for Drillahead Analysis ............................................... Analyzing Drillahead Results ...................................................................................... Using the BHA Analysis Data Quick Look Results .............................................. Supporting Information and Calculations........................................................................... Analysis Methodology ................................................................................................. Three Fundamental Requirements of Structural Analysis ..................................... Defining the Finite Element Mesh ......................................................................... Compute the Local Stiffness Matrix and the Global Stiffness Matrix .................. Degrees of Freedom ............................................................................................... Boundary Conditions ............................................................................................. Constructing the Wellbore and Bottom Hole Assembly Reference Axis .............. Calculating the Solution ......................................................................................... Bit Tilt and Resultant Side Force ........................................................................... Drillahead Solutions .............................................................................................. Bit Coefficient ........................................................................................................ Formation Hardness ............................................................................................... References...........................................................................................................................

499 500 501 501 501 502 502 504 505 505 505 506 506 506 508 510 515 521 521 522 522 525 525 525 525 526 531 531 534 535 535 538 539 540 541

Stuck Pipe Analysis ...................................................................................................... 543 Overview............................................................................................................................. Workflow ............................................................................................................................ Introducing Stuck Pipe Analysis......................................................................................... What is the Stuck Pipe Module? .................................................................................. Why Should I Use the Stuck Pipe Module? ................................................................ Starting Stuck Pipe ....................................................................................................... Defining the Case Data ....................................................................................................... xxii

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543 544 546 546 546 547 548

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Adding a Jar to the Workstring .................................................................................... Determining the Location of the Stuck Point ..................................................................... Defining Analysis Parameters and Viewing Results of Stuck Point Analysis ............ Determining the Surface Measured Weight Required to Activate the Jar.......................... Describing the Jar Analysis Mode ............................................................................... Selecting the Jar Analysis Mode .................................................................................. Defining Analysis Parameters and Viewing Results of Jar Analysis .......................... Analyzing the Output Section ................................................................................ Determining if the Required Measured Weight Yields the String...................................... Describing the Yield Analysis Mode ........................................................................... Selecting the Yield Analysis Mode ............................................................................. Defining Analysis Parameters and Viewing Results of Yield Analysis ...................... Analyzing the Output ............................................................................................. Determining if the Required Force at Backoff Connection Can be Achieved ................... Describing the Backoff Analysis Mode ....................................................................... Selecting the Backoff Analysis Mode ......................................................................... Defining Analysis Parameters and Viewing Results of Backoff Analysis .................. Analyzing the Output ............................................................................................. Supporting Information and Calculations........................................................................... Stuck Point Algorithm ................................................................................................. Stuck Pipe Yield Analysis Algorithm .......................................................................... Stuck Pipe Jar Analysis Calculations ........................................................................... Stuck Pipe Backoff Analysis Calculations .................................................................. References...........................................................................................................................

548 549 549 550 550 551 551 552 554 554 554 554 555 558 558 558 559 559 562 562 562 564 566 567

Notebook ............................................................................................................................. 569 Overview............................................................................................................................. Starting Notebook ........................................................................................................ Notebook Analysis Modes ........................................................................................... Miscellaneous Mode ........................................................................................................... Linear Weight .............................................................................................................. Blockline Cut Off Length ............................................................................................ Leak Off Test ............................................................................................................... Fluids Mode ........................................................................................................................ Mix Fluids .................................................................................................................... Dilute /Weight Up ........................................................................................................ Fluid Compressibility .................................................................................................. Hydraulics Mode................................................................................................................. Pump Output ................................................................................................................ Annular ........................................................................................................................ Pipe .............................................................................................................................. Nozzles ......................................................................................................................... Buoyancy ..................................................................................................................... Analysis Mode .................................................................................................................... WorkString ................................................................................................................... August 2004

Contents

569 569 570 572 572 573 573 574 574 574 575 576 576 576 577 578 578 579 579 xxiii


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Maximum String Length ........................................................................................ String Weight ......................................................................................................... Elongation .............................................................................................................. Volumes and Heights ................................................................................................... Lag Times .................................................................................................................... Spot a Pill ..................................................................................................................... Block Line Work ......................................................................................................... Rig Capacity ................................................................................................................ Calculations ........................................................................................................................ Block Line Cut Off Length .......................................................................................... Dilute/Wt Up Fluid ...................................................................................................... Fluid Buoyancy ............................................................................................................ Fluid Compressibility .................................................................................................. Leak Off Test ............................................................................................................... Mix Fluids .................................................................................................................... Pump Output ................................................................................................................ Nozzle Area .................................................................................................................

xxiv

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579 580 580 581 582 583 584 584 586 586 586 586 587 587 587 588 588

August 2004

Chapter 1

Introduction What is WELLPLAN? WELLPLAN is a drilling engineering software system to assist with solving engineering problems during the design and operational phases of drilling and completing wells. WELLPLAN is comprised of several modules including Torque Drag Analysis, Hydraulics, Well Control, Surge, OptiCem-Cementing, Bottom Hole Assembly, Critical Speed, Stuck Pipe, and Notebook. WELLPLAN can be used in the office or at the well site. WELLPLAN can be installed on a network for use by several individuals, or on an individual “stand alone” computer. Regardless of the installation location or type, data can be transferred between installations. In addition, WELLPLAN is integrated with other LANDMARK software and data can be shared between a variety of LANDMARK software packages. Refer to Chapter 2, “The Engineer’s Data Model (EDM) Database” on page 27 for more information.

Training Course and Manual Overview The purpose of this manual is to provide you a reference for entering data and performing an analysis during the class. Perhaps more importantly, you can refer to it after the class is over to refresh your memory concerning analysis steps. This manual contains technical information concerning the methodology and calculations used to develop this software. If you require more technical information than what is presented in this manual, please ask you instructor. The on-line help is very useful, and may assist you while using the software. This training class is designed to be flexible to meet the needs of the attendees. In this manual, there may be information regarding a module that you do not have. The training course begins with a quick introduction. Following the introduction, time will be spent covering the concepts and features common to all WELLPLAN modules. In this section you will learn how to navigate the system, enter data, and produce output. After these concepts and features have been reviewed, you will begin to look at the individual modules (Torque Drag Analysis, Hydraulics, Well Control,

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Chapter 1: Introduction

Surge, OptiCem-Cementing, Bottom Hole Assembly, Critical Speed, Stuck Pipe, and Notebook.)

Licensing FLEXlm is a licensing method common to all Landmark products. It provides a single licensing system that integrates across PC and network environments. FLEXlm Licensing files and FLEXlm Bitlocks are supported for Landmark Drilling and Well Services applications. Please refer to the EDT Summary Level Release Notes for more information.

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Chapter 2

The Engineer’s Data Model (EDM) Database Overview Many of Landmark’s drilling applications use a common database and data structure—the Engineer’s Data Model (EDM) database—to support the different levels of data that are required to use Landmark’s drilling and production software. The Engineer’s Desktop is Landmark’s Drilling, Well Services, Production, and Economics integration platform. The Engineer’s Desktop applications access the EDM database. EDM provides a common database schema that allows for common data access, enables naturally integrated engineering workflows, and reduces data entry duplication across applications. A significant advantage of the EDM database is improved integration between Landmark's Drilling and Well Services products, and the Production and Economics products. Integrated Engineering applications on EDM allow for improved Plan vs. Actual comparisons and complete store of design iterations from Prototype to Plan to Actual. In this chapter, you will be introduced to: Logging in to the database Data structure Common data Data locking Importing and exporting data

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Chapter 2: The Engineer’s Data Model (EDM) Database

Logging In To the Database Any Landmark drilling software using the Engineer’s Data Model (EDM) will require you to login. This dialog is used to select the database and to provide a user id and password.

Starting WELLPLAN You can start WELLPLAN in two ways: z

Use the Start Menu. Select WELLPLAN using Landmark Engineer’s Desktop 2003.11 > WELLPLAN.

z

Double-click any desktop shortcut you have configured.

The following login screen appears when you launch WELLPLAN:

Select the database you want to use from the drop-down list.

User will default to the last user name entered.

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Describing the Data Structure The EDM database has a hierarchical data structure to support the different levels of data that are required by different drilling suite applications. EDM uses the following hierarchical levels.

Database Company

Hierarchical database structure of the EDM database.

Project Site Well Wellbore Design Case

Landmark

Hierarchical Level

Description

Database

The Database is the highest level in the Well Explorer hierarchy. You can only work in one database at a time. Refer to “Working at the Database Level” on page 64 for more information.

Company

Company is the second highest data level in the hierarchy. You can define several companies within the database you are using. Each company must have a unique name. If you work for an operator, most likely you may have only one company. If you work for a service company, you may have several companies. Refer to “Working at the Company Level” on page 68 for more information.

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30

Hierarchical Level

Description

Project

Project is the data level directly beneath company and each project within a company must have a unique name. A project can be thought of as a field or as a group of sites. A project has one system datum (mean sea level, lowest astronomical tide, etc.) that is used to define 0 TVD for the project. Within the project, wellbores can be referenced to the project level system datum or to additional datums specified at the well level. Refer to“Using Datums in EDM” on page 48 or “Working at the Project Level” on page 75 for more information.

Site

Site is the data level directly beneath the Project level and each site within a project must have a unique name. A site is a collection of one or more wells that are all referenced from a local coordinated system centered on the site location. A site can be a single land well, an offshore sub-sea well, a group of well drilled from an onshore pad, or a group of wells drilled from an offshore platform. Refer to “Working at the Site Level” on page 79 for more information.

Well

Well is the data level directly beneath the Site level and each well within a site must have a unique name. A well is simply a surface location. A well can have more than one wellbore associated with it. For example, there may be the original wellbore with one or more sidetracks tied on to it at different kickoff depths. Refer to “Working at the Well Level” on page 85 for more information.

Wellbore

Wellbore is the data level directly beneath the Well level and each wellbore within a well must have a unique name. A wellbore is a compilation of one or more sections originating at the surface and continuing to a depth. A wellbore can be the original well drilled from the surface or a sidetrack drilled from a parent wellbore. If a well has an original hole and two sidetracks, the well has three wellbores. Refer to “Working at the Wellbore Level” on page 92 for more information.

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Hierarchical Level

Description

Design

Design is the data level directly beneath the Wellbore level and each design within a wellbore must have a unique name. A design can be thought of as a design phase. Associated with each design are a pore pressure group, a fracture pressure group, a temperature gradient and a wellpath. A design may have several cases associated with it, but each case will use the same pore pressure group, fracture pressure group, temperature gradient and wellpath. A design can be categorized as prototype, planned or actual. You may have several different versions of prototype designs. For example, assume the geologist wants to analyze two different formation fracture gradients. This could easily be accomplished by having two prototype designs that are identical except for the fracture gradient group. Landmark’s StressCheck, Casing Seat and COMPASS applications routinely use designs. Refer to “Working at the Design Level” on page 98 for more information.

Case (WELLPLAN only)

Case is the data level directly beneath the Design level and each case within a design must have a unique name. A case can be thought of as a snapshot of the state of the well. For example, you may use two cases to analyze the affects of varying the mud weight or changing the BHA. Associated with each case are an assembly, a hole section and one or more fluids. Cases are commonly used in Landmark’s WELLPLAN application. StressCheck and COMPASS do not use cases.

Note: The

Event hierarchy...

In the OpenWells, PROFILE, and Data Analyzer well explorer, you will find the Event level directly beneath the Wellbore level. For more information about Events, refer to the OpenWells online help.

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Associated Components Additional data components that can be associated ("linked") with Designs and Cases include Wellpaths, Pore Pressure Groups, Fracture Gradient Groups, Geothermal Gradient Groups, Hole Section Groups, Assemblies, Fluids, and Catalogs. These components are used to define the drilling problem that you want to analyze. All associated items, with the exception of fluids, are automatically created and associated by Well Explorer (you cannot manually create or associate these items) with the design or case. Fluids can be created/associated in WELLPLAN only, using the Fluid Editor. Catalogs function differently than the other components, primarily because Catalogs are not associated with a Design or Case. Catalogs are used as a selection list to design a casing, tubing, liner, or drillstring. Refer to “Working With Catalogs” on page 110 for more information. There are several additional data components that are associated with Designs or Cases. These are:

Associated with Designs:

Wellpaths A wellpath is a series of survey tool readings that have been observed in the same wellbore and increase with measured depth. All Cases within the same design use the same wellpath.

Pore Pressure Groups A Pore Pressure group is a set of pore pressures that define the pore pressure regime over a depth range from surface to some vertical depth. All Cases within the same design use the same pore pressure.

Fracture Gradient Groups A Fracture Gradient is a set of fracture pressures that define the fracture gradient regime over a depth range from surface to some vertical depth. All Cases within the same design use the same fracture gradient.

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Geothermal Gradient Groups A Geothermal Gradient is a set of undisturbed earth temperatures that define the temperatures over a depth range from the surface to some vertical depth. All Cases within the same design use the same geothermal gradient.

Associated with Cases:

Hole Section Groups A Hole Section defines the wellbore as the workstring would see it. For example, a hole section may contain a riser, a casing section, and an open hole section. A hole section can also have a tubing section or a drill pipe section depending on the situation. Multiple cases may use the same hole section.

Assemblies An Assembly defines the workstring. There are several types of workstrings, including coiled tubing, casing, drillstrings, liners, and tubing strings. Multiple cases may use the same assembly.

Fluids A Fluid defines a drilling, cementing, or spacer fluid. A Fluid is linked to a Case and a Case can have more than one fluid linked to it. One fluid can be linked to multiple cases.

Copying and Pasting Associated Items All of these associated items, with the exception of fluids, are automatically created and associated ("linked") by the Well Explorer to the design or case. (You cannot manually create or link these items.) Fluids can be created/linked in WELLPLAN only, using the Fluid Editor. All these items are visible in Well Explorer so that you can copy and paste them using the right-click menu. For example, when you copy a wellpath and paste it into a different design, the wellpath that currently exists for the target design is deleted. Well Explorer replaces the old wellpath with the copy of the new one.

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Again, fluids are the exception. Only the WELLPLAN Fluid Editor can delete fluids, so after pasting a fluid, the original fluid still exists. The original fluid is no longer linked to anything. This can’t be seen in Well Explorer, but WELLPLAN can access this. Note that if the destination case, or the fluid you are trying to replace is locked, a message appears and the paste is not completed.

Rules for Associating Components The rules for associating components are listed below. For Definitive Surveys, Pore Pressure Groups, Fracture Gradient Groups, Geothermal Gradient Groups, Assemblies, and Hole Sections: • • • •

•

Each component can only be associated with one Design or Case. When one component is copied and pasted, an actual copy is made. When one component is pasted, the component it replaces will be deleted (unless it is locked). If the destination for the paste is locked (Design or Case) or the item to be replaced is locked, a message appears and the paste is not completed. If the design is locked, all it’s associated items are also locked.

For Fluids: • • • •

34

When a fluid is copied and pasted, an actual copy is made. When a fluid is pasted, the one is replaces will NOT be deleted. Fluids can only be deleted using the Fluid Editor in WELLPLAN. If the destination case is locked or the fluid to be replaced is locked, a message appears and the paste is not completed.

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Common Data Common data stored in the EDM database and available for use by StressCheck, CasingSeat, WELLPLAN, OpenWells, and COMPASS in database mode include: • • • • • • • • •

Unit system Pipe catalog Connections catalog Pore pressure Fracture Gradient Temperature Gradient Surveys All fields in Well Explorer Properties dialogs General data, such as Well Name, Well Depth, Vertical Section information

Note: Several additional fields are common to two or more applications, but not all. Drilling applications may share other data not listed.

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Data Locking You can prevent other people from making changes to data by locking data at various levels and setting passwords. Users can only open the data item in read-only mode; to keep changes, they will have to use Save As or Export.

How Locking Works You can lock Company properties only, or you can lock properties for all levels below Company (Project, Site, Well, Wellbore, Design, and Case). Passwords can be set to prevent unlocking. By default, no passwords are set, and the "locked" check box on all Properties dialogs can be toggled on and off at will with no security to prevent users from doing something they shouldn’t. In the Well Explorer, if a data item is locked a small blue "key" appears in the corner of its icon. When you open a locked data item, you will see the message "This Design is locked and therefore Read-Only. Changes to this Design will not be saved to the database. To keep your changes, use the Save As or Export options."

Locking Company Properties In the Properties dialog for the company whose data you want to protect, there are two buttons, Company Level and Locked Data, and a checkbox, Company is locked. When you click the Company Level button, you are prompted to set a password to protect Company properties (and only the Company properties). This password will then be required if a user wants to "unlock" company properties and make changes. Once the password is set, toggle the Company is locked checkbox on to lock the company properties and prevent unauthorized changes to the data.

Locking Levels Below Company When you click the Locked Data button on the Company Properties dialog, you are prompted to set a password. This password will then be

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required if a user wants to "unlock" any level below the company (projects, sites, wells, wellbores, designs, and cases). All levels are locked individually—that is, you can lock a Well, but this doesn’t mean that anything below it is locked. Once the Locked Data password is set, you can lock properties for any data level below Company and prevent unauthorized changes to the data. Open the Properties dialog for the data level you want to lock and toggle the "locked" checkbox on. (For example, to lock a Wellbore, open the Wellbore Properties dialog and toggle Wellbore is locked on.)

Note: Locked

Designs...

When a design is locked, all associated items (Pore Pressure, Fracture Gradient, Geothermal Gradient, and Wellpath) are locked with it.

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Simultaneous Activity Monitor (SAM) The 2003.11 release of EDM (the Engineer's Data Model) supports full concurrency for multiple applications using the same data set through the Simultaneous Activity Monitor (SAM). For in-depth information on SAM, refer to the EDM Administration Utility help. If the Simultaneous Activity Monitor has not been configured, the following message will appear: "WELLPLAN could not connect to the SAM server. Please verify that the settings are configured correctly in the administration utility, and that the SAM server is running." The Simultaneous Activity Monitor consists of a Messaging Server that notifies the user with an open application of all data currently open in other applications. The SAM icon appears in the application Status Bar as follows:

Icon

Message Description A green SAM icon in the status bar indicates that the Messenger service is active. A blue SAM icon with a red X on it indicates that the Messenger Service is not currently active.

No Icon

When no icon appears in the application status bar this indicates that the Simultaneous Activity Monitor has not been configured for the application.

If a data item is open, an icon will appear as follows: z

A red SAM icon indicates that one or more users on other PC’s have this item open and the current user is restricted to read-only access.

A blue SAM icon indicates that one or more users on the current PC have this item open but the current user still has full read-write access. A user must be careful when making changes to the date though this method enables data to automatically flow between applications.

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Concurrent Use of Same Data By Multiple Users The 2003.11 release supports concurrency for multiple users on the same data set. The Simultaneous Activity Monitor (SAM) is the service used to regulate concurrent access to the EDM database. z

By default, the SAM server is enabled and connected and you will see a green "SAM" icon in the status bar of your application.

z

If the SAM service is configured but not connected, the "SAM" icon will appear with a red "X" drawn through it. Consult your System Administrator.

z

If the SAM service is not configured, there will be no SAM icon in the status bar.

For in-depth information on SAM, refer to the EDM Administration Utility help. A good practice for any multi-user environment is to frequently use the F5 refresh key to refresh the Well Explorer contents. Data updates (e.g., inserts, updates, deletions) are not always automatically recognized in other EDT sessions and simultaneously run EDT applications.

How the Well Explorer Handles Concurrent Users Basically, the Well Explorer and the Simultaneous Activity Monitor handle concurrency like this: If a user on a different machine has a Design open (first one to open the Design gets it in Read/Write mode), then all other users can only open that Design in Read-Only mode. If no one on any other machine has Read/Write access to the Design, then you get Read/Write access. This is the SAM icon: The red "SAM" icon indicates that one or more users on other PC’s have this item open and you are restricted to opening it in Read-Only mode. You cannot save any changes to the database, but you can use Save As and rename the item. The blue "SAM" icon indicates that one or more users on the current PC have this item open, but you can still open it in Read/Write mode. You can save changes to the database. Landmark

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These SAM icons will appear on a Design (COMPASS, WELLPLAN, StressCheck, CasingSeat) or a Well (OpenWells) in the Well Explorer.

Same User on Same Computer If the same user has a Design open in one EDT application and then opens the same Design in another EDT application on the same machine, the blue "SAM" icon will appear in the Well Explorer of the second application. This indicates that this user has the Design "locked for use in Read-Write mode", and has it open in more than one application. However, because it IS the same user, he/she can Save changes to the database made from either application.

Multiple Users, Different Computers The first user to open a Design or Case in that well gets control, and the Design or Case is then "locked for use in Read/Write mode." A red "SAM" icon indicates that more than one user is working with the Design or Case at the same time. However, only the first user can make changes; all other users open the Design or Case in Read-Only mode. They can Save As, but not Save. After the user who had access to the Design or Case in Read/Write mode closes the Design or Case, the red "SAM" icon goes away, and the Design or Case is available again. Read-only users will have to close the Design or Case and re-open to gain control. (WELLPLAN only) A user can save Cases under a Design that is currently "locked for Read/Write use" by someone else.

Reload Notification If you are working with any of the data in the following list, and a user with read/write privileges saves changes to the database, you will receive a notification indicating that another user has changed the data you are working with. You will have the opportunity to use the changes saved to the database by the other user. You will also have the opportunity to save the data you are working with using the Save As option. If you do not save your data using Save As, your changes will be overwritten by those made by the other user. (Your changes will only be overwritten if the other user saves his changes, and you indicate you want to use those changes when you receive notification.) Keep in mind that if you have read privileges, any

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changes you make are only stored in memory and are not written to the database unless you save your data using Save As. Items that are refreshed in this manner are: Design, Definitive Survey (Wellpath), Pore Pressure, Fracture Gradient, Geothermal Gradient, Assemblies (Casing Scheme)

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Importing and Exporting Data WELLPLAN provides you with EDM database import and export functionality, as well as flat file import and export functionality.

Importing Data into the EDM Database You can import data from one EDM database into another EDM database, or you can import a DEX file. Note: Importing WELLPLAN and COMPASS legacy data... WELLPLAN and COMPASS legacy data must be imported into the EDM database using the Data Migration Toolkit. See the PDF file "Using the Data Migration Toolkit" in the Landmark Engineer’s Desktop 2003.11\Documentation folder for details.

Importing EDM Well Data from Another Database To import well data from one EDM database to another, follow these steps: 1. In the Well Explorer, select the EDM database canister. 2. From the Well Explorer right-click menu, select Import. The following dialog box opens:

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3. Select the .XML file containing the well data you want to import, and click Open. (Well data can be saved in .XML format using the Export command in the Well Explorer; see page 45 for details.) Note: XML file naming... EDM Data Transfer File imports are not supported from paths containing apostrophes or filenames containing apostrophes. Make sure that you do not use apostrophes in filenames or directory names.

4. The well data will be imported into the database.

Importing a DEX File Into the Database To import a DEX file into the EDM database, follow these steps: 1. Select File > Data Exchange > Import. The following dialog box opens:

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2. Specify the filename for the well information in DEX format you want to import, and click Open. The following dialog appears.

3. Use the arrow buttons to move the desired data items into the lower list box. Single arrow buttons move the highlighted file(s). Double arrow buttons move all files. (Use the upward facing arrows to remove items from the desired selection.) 4. Click OK to start the import. Note: Data imported to memory... The data will be imported into memory and displayed in the main window. The data has not yet been saved to the database. You may make changes now, if you wish.

5. When you are ready to save the changes to the database, select File > Save. The Save As dialog opens, allowing you to specify where in the hierarchy to place the newly imported design, and to name the design. Click Save. The newly created design will appear in the Well Explorer tree.

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Exporting Data From the EDM Database You can export well data from the EDM database in .XML format; this data can then be imported directly into another EDM database. You can also export data in DEX format.

Exporting Data in XML Format To export well data for import into another database, follow these steps: 1. In the Well Explorer, select the company, project, site, well, wellbore, design, or case whose data you want to export and rightclick to open the pop-up menu. Select Export. The following dialog box opens:

2. Specify a filename for the information you want to export, and click Save. The parent and child data, and any linked pore pressures, fracture gradients, etc. will be saved to the .XML file you specified.

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Exporting Well Data in DEX Format 1. Select File > Data Exchange > Export from the main menu. The following dialog box opens:

2. Specify a filename for the well information you want to export in DEX format, and click Save. If this is the first time you have saved DEX data using the specified filename, the export is complete at this point. If the specified file already existed, the following dialog opens to allow you to specify which objects you want to export.

3. Use the arrow buttons to move the desired data items into the lower list box. Single arrow buttons move the highlighted file(s). Double arrow buttons move all files. (Use the upward facing arrows to remove items from the desired selection.)

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4. Click OK to start the export. The data will be saved to the .dxd file you specified.

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Using Datums in EDM Definition of Terms Associated With Datums Datum terms are defined below, and are grouped by the Properties dialog in which they are found.

Project Properties

System Datum: The System Datum is set in the Project Properties > General dialog, and represents absolute zero. It is the surface depth datum from which all well depths are measured, and all well depths are stored in the database relative to this datum. Usually the System Datum is Mean Sea Level, Mean Ground Level, or Lowest Astronomical Tide, but it can also be the wellhead, rigfloor, RKB, etc.

Elevation: The Elevation is set in the Project Properties/General dialog, and represents the elevation above Mean Sea Level. (If Mean Sea Level is selected as the System datum, Elevation is grayed out.)

Well Properties

Depth Reference Datum(s): The Depth Reference Datum represents zero MD. It is sometimes known as the local datum, and is measured as an elevation from the System Datum. You can define one or more Depth Reference Datums for a well in the Depth Reference Tab (Well Properties Dialog). For each Depth Reference Datum, you must specify the elevation above or below the System Datum. The selected default Depth Reference datum in the list box will be the viewing datum in all applications (the viewing datum can be changed ‘on the fly’ only in OpenWells and COMPASS.)

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You can’t delete or change the elevation of a Depth Reference datum once it is referenced by a Design.

Offshore check box: Check to indicate that this is an offshore well; leave unchecked to indicate a land well.

Subsea check box: (offshore well) Check to indicate that this offshore well is subsea.

Ground Elevation: (land well) This is the elevation of the ground above the System Datum; it is set in the Depth Reference Tab (Well Properties Dialog).

Water Depth: (offshore well) This is the total depth of the column of water (MSL to mudline); it is referenced to Mean Sea Level.

Mudline Depth: (only for offshore subsea well) This is the depth below system datum (MSL/LAT etc.) of the wellhead flange.

Wellhead Depth: (subsea well) This is the distance from the wellhead to the system datum, and is used in some calculations where this is the hanging depth for casing leads when set. To determine wellhead depth: Wellhead Depth (to rig floor) = Depth Reference Datum + Wellhead Depth Wellhead Depth (set in the Well Properties > Depth Reference tab) is positive for offshore subsea and negative for wellheads above MSL (i.e., onshore or offshore platform). So, it does not matter in the above calculation whether it is offshore or subsea. Depth Reference Datum is always positive. Both wellhead depth and wellhead elevation are distances from the system datum to the flange.

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Wellhead Elevation: (platform and land wells) This is the height above system datum (MSL/LAT) of the wellhead flange (surface casing). It may happen that for some land wells using ground level as the system datum that the user may have to enter a negative value because the wellhead 'cellar' is often below the ground.

Air Gap (calculated) This is the distance from the system datum to the rig floor, and is used in some calculations for hydrostatic head. Air Gap is always positive. To calculate air gap, the application uses: z

Air Gap (offshore wells) = Depth Reference Datum – Elevation

z

Air Gap (land wells) = Depth Reference Datum – Ground Level

Elevation is set on the Project Properties > General tab and ground level is set in the Well Properties > Depth Reference dialog.

Design Properties

Depth Reference Information: From the drop-down list of defined Depth Reference datums, select the datum you want to reference for this Design. Once you select a datum, the Datum Elevation, Air Gap, current System Datum, Mudline Depth, and Mudline TVD are all updated/calculated and displayed adjacent to the rig elevation drawing on the Well Properties > Design Properties tab.

Setting Up Datums for Your Design 1. Using the Project Properties > General dialog, select the System Datum you want to use. 2. Using the Project Properties > General dialog, in the Elevation field, enter the value the System Datum is above Mean Sea Level. If your System Datum is below Mean Sea Level, this number will be negative. If your System Datum is Mean Sea Level, Elevation is grayed out. 3. If the well is offshore, use the Well Properties > Depth Reference dialog to:

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a) Check Offshore, and enter the Water Depth below the System Datum. b) If the well is subsea, check Subsea and enter the Wellhead Depth below the System Datum. 4. If the well is a land well, use the Well Properties > Depth Reference tab, make sure Offshore is unchecked, and enter the Ground Level elevation above the System Datum. 5. Using the Well Properties > Depth Reference tab, define the Depth Reference Datum (s) you want to use, such as RKB or Rigfloor. Type the elevation above the System Datum in the Elevation field, and specify the effective Date for the datum. 6. Import or create a design for this well. 7. In the Design Properties dialog, General tab, select the Depth Reference Datum you want to use for this design from the dropdown list of datums you defined in Step 5.

Changing the Datum (WELLPLAN Only) If a Design was created using one Depth Reference datum, and the Depth Reference datum is changed, then when the Design is opened any depths that become negative will be changed to zero, and all depth-related properties will be adjusted accordingly. (StressCheck and CasingSeat Only) When you create a design and save it for the first time, the EDM database keeps track of the Depth Reference Datum that was set at the time. This "original" Depth Reference Datum is not displayed; however, if you or someone else changes the Depth Reference Datum in the Well Properties dialog, and you then attempt to open that design, a warning message will appear. You are warned that you are trying to change to a datum that is different from the datum in which you originally saved the data, and any calculations will be invalid unless you change your inputs (see details here). You are given the choice to open the design/case in the original datum, or to convert to the new datum. If you choose to convert your data, the data will be adjusted. However, the change is NOT saved to the database until you save the design, at which time the new datum becomes the "original" datum.

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How this works:

If datum is same as original datum: If you open a design or case where the Depth Reference Datum (set at the Design level) is the same as the datum the data was originally saved in, the design/case will open normally.

If datum is different than the original datum: If you open a design or case where the Depth Reference Datum (set at the Design level) is different from the original datum, the following occurs: 1. The application checks to see if the well is a slant hole. If positive inclination exists in wellpaths whose depths would become negative after the datum shift, the program cannot make the adjustments; a message pops up to inform you of this. Click Open to open the design in the original datum; if you click Cancel, the design will not open at all. 2. For wells other than slant holes, the program will issue this message: "The currently selected design datum is different to the datum with which the design was created. The application will then attempt to adjust the data, but some data might be shifted or removed. If you open the design, we strongly suggest that you review your input data; any changes will not be saved to the database until you explicitly save your data. Please select "Open" to review the design using the datum with which it was created." If you want to open the Design with the original elevation, select Open. If you want to convert the data to the new elevation, select Adjust. Open is the default. • If you enter "Open": Data is loaded to the original design datum, but the Depth Reference Datum set in the Design will NOT change to match the original datum. • If you enter "Adjust": Well Explorer loads the data to the new Wellbore datum and attempts to adjust the data; however, some data may be shifted or removed. The program will resolve the deltas in the first depths of column data (strings, wellpaths,

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columns, etc.) to adjust for the new gap and read zero depth on the first line. Note: After

Opening a Design...

Once you open the design you should review your input data; remember that the changes will not be saved to the database until you explicitly save your data.

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Chapter 3

Using the Well Explorer Overview In this chapter, you will become familiar with using the Well Explorer. You will expand your knowledge of the hierarchical levels of the EDM database you discussed in the last chapter. In this section of the course, you will become familiar with: Components of the Well Explorer Data levels accessible using the Well Explorer Items associated with each data level Creating a new company Creating a new project Creating a new site Creating a new well Creating a new wellbore Creating a new design Creating a new case Catalogs

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Chapter 3: Using the Well Explorer

Describing the Well Explorer The Well Explorer allows you to browse the Engineer’s Data Model (EDM) database at seven hierarchical levels: companies, projects, sites, wells, wellbores, designs, and cases. Using the tree-like interface, you can perform basic file management tasks within the Well Explorer. The Well Explorer display will vary slightly from one application to another. For example, Drilling applications that do not use Cases (such as StressCheck, CasingSeat, and COMPASS) will not display Cases in their Well Explorer. Production products (TOW, DSS, and ARIES) use the Desktop Navigator to navigate through production hierarchical entities. The Well Explorer is shown in the following figure. Click to display or hide the Well Explorer (located on the main toolbar) The Recent Bar displays the last selected data items; use it to quickly open recently used items.

Well Explorer

The currently selected data item is a Case in this example. The Associated Data Viewer displays items associated with the selected data item. (A case in this example.) You can open the associated item’s editor by double-clicking on the item in the viewer.

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Word document is linked to the selected Design as an “attached document”.

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Components of the Well Explorer The Tree The hierarchical tree functions much like the Microsoft Windows Explorer. You can view and manipulate different levels within the EDM data model hierarchy, in a fashion similar to a directory tree. Operations are: •

Left mouse button is used to expand or contract branches of the data tree and to select. Click the + sign to expand the hierarchy and click the - sign to contract it. Refresh the display with the F5 key.

•

The right mouse button has a context-sensitive menu. Depending on the hierarchical level you have highlighted (Company, Project, Site, Well, Wellbore, Design, Case, Wellpaths, Pore Pressure Groups, Fracture Gradient Groups, Geothermal Gradient Groups, Hole Section Groups, Assemblies, Fluids, and Catalogs) the menu will populate with all of the relevant options. (New data item, New Attachment, Copy, Paste, Delete, Properties, etc.)

•

On-Demand Editing: By double-clicking on the Wellpath, Pore Pressure, Fracture Gradient. or Geothermal Gradient, you can open their respective spreadsheets directly from the Well Explorer for editing. Alternatively, you can right-click on these items and select Open.

Associated Data Components Data components that are associated with a design or case are displayed in the Associated Data Viewer at the base of the Well Explorer.

Data Components Associated With a Design Data components that can be associated with a design are: Attached documents, Fracture Gradient Groups, Pore Pressure Groups, Geothermal Gradient Groups, and the Wellpath associated with the design. The data items associated to the design are used in all the cases below the design in the hierarchy. By double-clicking on the Geothermal Gradient, Wellpath, Pore Pressure, or Fracture Gradient, you can open their respective spreadsheets directly from the Well Explorer for editing. Alternatively, you can right-click on these items and select Open.

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Data Components Associated With a Case Data components that can be associated with a Case are: Attached Documents, Assemblies, Hole Sections, and Fluids. The associated items can be used in more than one case. WELLPLAN is the only Landmark Drilling software application that uses Cases, so associating data to a Case pertains only to WELLPLAN. Note: If you change a fluid, assembly, or hole section that is used in more than one case... the change affects all cases associated to that fluid, assembly, or hole section.

Attached Documents You can "attach" any kind of file or shortcut created in Windows to the selected data item (Design Case, etc.) in the Well Explorer tree. Attached documents are associated with the selected data item, will be displayed in the Associated Data Viewer at the base of the Well Explorer, and can be launched in their native applications by doubleclicking. You can attach Word documents, Excel spreadsheets, pictures (GIF, TIFF, JPG, PowerPoint, etc.), or other file types with a recognized extension. For example, if you have a Design selected in the Well Explorer, you can attach a map of the rigsite in JPG format. Attachments can be stored in the database as a copy, or as a link to a disk file. z

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Link: Only the link to the disk file is stored in the database. Any edits you make are saved to the original disk file. You can edit the document directly from the Well Explorer, or you can edit the disk file from it’s disk location; the changes are reflected in both places. When stored as a link the attachment can only be accessed by users whose contact to the attachment is not limited by their access to the machine or network access. Attachments stored as a link can be edited by any user with access to the original document through the link. When an attachment is added as a link, it can only be viewed on the machine in which the attachment was initially added. For all other users the shortcut is visible and acts as a placeholder to inform users that it exists. Any information on the shortcut should be placed in the properties page description field, since the properties of the shortcut are visible in the preview pane for all users. Landmark recommends use of UNC file paths to avoid problems with inconsistently mapped network drives. In the Associated Data Viewer, the icon representing a Linked document

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is shown as a paperclip with a small arrow in the lower left corner. This is the default behavior. z

Copy: The document is copied to the database. Once copied, the document has no relationship with the original disk file; if you make changes to the Well Explorer copy, those changes are not reflected in the disk file, and vice-versa. Attachments stored in the database cannot be directly edited. When a change is made to the attachment it is stored locally and must be re-added to the database and either renamed or the existing attachment replaced. In the Associated Data Viewer, the icon representing a Copied document is shown as a paperclip.

Attached documents can be copied from one data item to another using the right-click Copy option, saved to another name using Save As, and deleted (if copied) or detached (if linked) using Delete. To view the current properties of the attachment, select Properties from the rightclick menu.

To Attach a Document 1. With the selected data item (Design, for example) selected in the tree, right-click and select New Attachment. 2. A dialog box will open, allowing you type a Description of the document, and Browse for the Attachment path to the document’s location. Click the Save attachment as a link/shortcut only checkbox if you want to save the attachment as a link. If you leave this box unchecked the document will be copied. 3. Click OK. The attached document will appear in the Associated Data Viewer at the base of the Well Explorer.

To Delete an Attached Document 1. In the Associated Data Viewer, select the attachment you want to delete. 2. Right-click and select Delete. If it is a Copied attachment, the document will be deleted. If it is a Linked attachment, only the link will be deleted from the database; the disk file will still exist.

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To Copy an Attached Document to Another Data Item 1. In the Associated Data Viewer, select the attachment you want to copy. 2. Right-click and select Copy. In the Well Explorer, navigate to the desired data item (a Case, for example). Right-click and select Paste. (Or, drag and drop the attachment from one data item to another.) The Associated Data Viewer for that data item will display the copied attachment.

The Recent Bar To save time, you can use the Recent bar to select a recently used Design, Case, or Catalog, instead of browsing for the desired item in the Well Explorer.

The Recent bar is usually displayed near the top of the application window along with the rest of the toolbars. To display the list of recently used designs, cases, or catalogs, click on the drop-down list. Select the item you want to use from the list, and it will be displayed in the main window.

Displaying/Hiding the Well Explorer and Recent Bar By default, the Well Explorer and Recent Bar are displayed. To toggle between displaying and hiding the Well Explorer and Recent Bar, select View > Well Explorer, or click the icon on the Database toolbar.

Refreshing the Well Explorer Press the F5 key to refresh the Well Explorer.

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Positioning the Well Explorer By default, the Well Explorer is normally found just below the menu bar, on the left side on the main window. However, the Well Explorer is “undockable,” which means it can be moved around the application frame and adjusted to fit your needs. To undock the Well Explorer, click anywhere on the Well Explorer’s light gray border and drag it away from its present position. When the toolbar is attached to any edge of the application frame (such as the menu bar) and then moved away from it, its border changes. At this point you can release the mouse button. The Well Explorer resides in a palette window that “floats” above the application frame. You can move the Well Explorer to another portion of the screen by clicking anywhere in its light gray border or title bar and then dragging it. To re-dock the Well Explorer, drag it to any edge of the application frame. When the Well Explorer approaches a valid docking position, its border suddenly changes, at which point you can release the mouse button.

Tracking Data Modifications You can track modification of data using the Audit tab on the Properties dialog for each data type (using the Well Explorer, right click on Company, Project, Site, Well, Wellbore, Design, Case, Catalog,

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Wellpath, Pore Pressure, Fracture Pressure, Geothermal Gradient, Hole Section, Assemblies, or Fluids, then click the Audit tab). This information indicates who created the company, project, site, well, wellbore, design, etc. Also displayed is the date the item was created as well as the application that was used to create the item. This information indicates who modified the company, project, site, well, wellbore, design, etc. Also displayed is the date the item was modified as well as the application that was used to modify the item.

Type comments as desired to assist with tracking the use of the software. New comments are appended to existing comments.

Drag and Drop Rules "Drag and drop" in the Well Explorer functions somewhat like the Microsoft Windows Explorer. You can use drag and drop to copy Companies, Projects, Sites, Wells, Wellbores, Designs, Cases, as well as associated data items and attached documents. All drag and drop operations copy the data; data is never cut or moved. z

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To copy - Drag and drop the item to copy it from one location and paste it into another. The item and all associated data will be copied and pasted.

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You can drag and drop associated items (Wellpaths, Pore Pressures, Fracture Gradients, Geothermal Gradients, Hole Sections, Assemblies, etc.) into open Designs or Cases from the Associated Data Viewer at the base of the Well Explorer. The application will automatically update itself with the copied data. Some rules: z

You cannot drag and drop an Actual Design. However, if you copy a Wellbore, any Actual Designs under that Wellbore are copied. This is also true for copying done at the Well, Site, Project, and Company level.

z

You cannot drag a Wellpath from the Associated Data Viewer into an Actual Design.

z

If you drag a Planned or Prototype Design to a different Project, targets will not be copied with the Design. As a result, the plan will no longer have any targets associated with it.

z

Depending where a Design sidetrack Wellbore is dropped, Plan and Survey tie-on information may be lost, and as a result, survey program may be missing information.

z

(COMPASS only) If a Survey is dropped onto a Wellbore or Actual Design in another Company, the Survey will lose its tool information.

z

You cannot drag and drop Catalogs. Instead, you must use the rightclick menu Copy and Paste functions

Well Explorer Right-Click Menus When you click on something in the Well Explorer (a Well, Design, etc.), right-clicking brings up a menu of options pertinent to that

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hierarchical level. The options on each hierarchical level are discussed below.

Working at the Database Level When a Database is selected on the Well Explorer, the following rightclick menu items are available: Command

Description

New Company

Choosing this option displays the Company Properties dialog. (page 64)

Instant Case

Use Instant Case to quickly create a new case. Choosing this command displays the Instant Case dialog box, which allows you to quickly select the hierarchy you want Company, Project, Site, Well, Wellbore, Design, and Case- from drop-down lists of existing database entries. After making your selections, click OK to create the Case. (page 65)

Export

Use Export to make a copy of all libraries and write them to an XML file. This XML file can be sent to another user so that they can use any libraries you may have created. (page 66)

Import

The Import command allows you to import .xml files, libraries, and workspace files into the database that was exported using the Export command. See “Import (Database Level)” on page 66 for more information. (page 66)

Properties

The Properties command allows you to specify the real-time configuration information for the database.

Well Name

Choosing this option displays a sub menu from which you can select how to name the wells in your project. (page 67)

Wellbore Name

Choosing this option displays a sub menu from which you can select how to name the wellbores in your project. (page 68)

Refresh

Use this command to refresh (update) the Well Explorer tree with any changed information. Pressing the F5 key is another way to refresh. (page 68)

Expand All

To expand all levels below the Database level. (page 68)

Collapse All

Use this command to collapse all levels below the Database level. (page 68)

New Company (Database Level) To create a new company, select the database canister and right-click; select New Company. The Company Properties dialog opens. The fields and controls on the Company Properties dialog are explained in detail on page 71.

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If you want to “lock” the data and prevent changes to the company-only data, set the Company Level password; to prevent changes to the company data and all levels below it, set the Locked Data password. Toggle “Company is locked:” on after setting passwords.

Instant Case (Database Level) Use this dialog to quickly and easily create the hierarchy required to start a case, from the company all the way down to the design. This allows you to enter minimal information and the effort of going through the individual property dialogs at each level of the hierarchy. Select the Company, Project, and Site from the drop-down list of existing companies, projects, or sites. You can also enter a new name for the data level.

Enter the name of the Well, Wellbore, and Plan.

Specify datum information.

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Export (Database Level) The Export command allows you to export all libraries (fluid and string) that you have created to an xml file. You can provide the xml file to another user. That user can import the file containing the libraries and can then use the libraries you created. Refer to “Using Libraries” on page 148 for more information.

Import (Database Level) The Import command allows you to import a .xml file containing data, libraries, or workspaces into the database that was exported using the Export command. If the import file contains analysis data, the entire hierarchy of the Well (Company, Project, and Site, and well as any child data, such as Wellbore, Design, etc.) are included in the file. When you select Import, the Import well dialog opens, prompting for the XML filename to import. Type the filename, or browse for the file. Click Open. The Well hierarchical data will be imported into the EDM database.

Properties (Database Level) Use the Properties command to access the Real-Time Configuration tab. This tab is used to specify real-time mnemonics for log curves that are going into the EDM database via OpenWire for use in real-time Torque and Drag/Hydraulics analyses in WELLPLAN. When you set the realtime configuration properties at the database level, every company within the database will inherit those real-time properties. However, you can change the real-time properties for an individual company within the database by right-clicking on the company and selecting Properties > Real Time Configurations tab. Real-Time Configuration Properties... You must have correctly specified log mnemonics prior to initiating data transfer using OpenWire. If the mnemonics are not correctly specified, the data transfer will not occur.

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Real-Time Mnemonics are Case Sensitive... Real-time mnemonics are case sensitive. Be sure to type them into the Real-Time Configuration tab just as they will appear in the WITSML 1.2 data from your service provider.

Mnemonics are case sensitive! Be sure to type them just as they will appear in the WITSML 1.2 data.

Well Name (Database Level) Choosing this option displays a sub menu from which you can select how to name the wells in your project. The options are: z

Common Name - Short/abbreviated well name given to well for day-to-day reference.

z

Legal Name - Formal well name assigned for documentation purposes.

z

Universal Identifier - A coded well name that varies from region to region.

Note: You can choose only one of the naming options Common Name, Legal Name, or Universal Identifier. You can use Slot Name in conjunction with the other naming conventions.

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Wellbore Name (Database Level) Choosing this option displays a sub menu from which you can select how to name the wellbores in your project. The options are: z

Common Name - Short/abbreviated well name given to well for day-to-day reference.

z

Legal Name - Formal well name assigned for documentation purposes.

z

Universal Identifier - A coded well name that varies from region to region.

Note: You can choose only one of the naming options Common Name, Legal Name, or Universal Identifier.

Refresh (Database Level) Use this command to update the Well Explorer tree to show any additions, changes, and deletions.

Expand All (Database Level) This command expands all nodes below the selected level in the Well Explorer tree.

Collapse All (Database Level) This command collapses all nodes below the selected level in the Well Explorer tree.

Working at the Company Level In the Well Explorer, when you right click on a company, the right click menu displays the following choices:

Command

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Description

New Project

Create a new project for the selected company (page 69).

New Attachment

Displays the Attachment Properties dialog. (page 70)

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Paste

Paste copied company information from the Clipboard (page 70).

Rename

Activates the selected data item in the Tree, enabling you to edit the name. (page 70)

Delete

Delete the selected company and all associated child information (page 70).

Export

Export the selected company’s hierarchical information to an XML file (page 71).

Properties

View or edit the selected company’s properties (page 71).

Expand All

To expand all levels below the company level in the Well Explorer (page 74).

Collapse All

Collapses all levels below the company level in the Well Explorer. (page 74)

New Project (Company Level) To create a new project, select a Company and right-click; select New Project. The Project Properties dialog opens.

The fields and controls on the Project Properties dialog are explained in detail on page 77.

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New Attachment (Company Level) Use this dialog to associate a document or picture (Word, Excel, text file, JPG, etc.). Document can be of any type with a recognized extension. Enter text that provides detailed descriptive information about this attachment.

Use the Browse button to navigate to the location of the file. If you know the path, you can enter it without using the Browse button.

Check the Save attachment as a link/shortcut only box if you want to save the attachment as a link only. If you check this box, only the link to the disk file is stored in the database. Any edits you make are saved to the original disk file. You can edit the document directly from the Well Explorer, or you can edit the disk file from its disk location; the changes are reflected in both places. In the Associated Data Viewer, the icon representing a Linked document is shown as a paperclip with a small arrow in the lower left corner.

Paste (Company Level) Use this command to paste (insert) the contents of the Clipboard at the location currently selected in the Well Explorer. In order for this function to be effective you must have Copied (saved) company data to the Clipboard.

Rename (Company Level) Use this command to rename the item. You can also rename the data hierarchy item by highlighting it and the clicking once on it. Type the new name in the box that appears around the current name.

Delete (Company Level) Use this command to remove the selected Company from the database. A confirmation box will open, asking if you are sure you want to delete the company and all its associated data. Click Yes or No, as appropriate.

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Export (Company Level) Use this command to export the selected Company’s data in XML format. Includes any child information associated with the Company. A dialog will open, allowing you to supply a directory and filename for the XML file.

Properties (Company Level) Selecting this command allows you to view or edit Company properties. The Company Properties dialog opens.

Company Properties Dialog The Company Properties dialog is used to create a new company and to provide information regarding creation and modification of the company. This dialog contains three tabs: General, Real Time Configuration, and Audit.

General Tab (Company Properties Dialog) Use to specify a unique company name that identifies the company, and to provide additional information related to the company. This tab is also used to lock the company and/or associated data to protect against undesired changes to the data associated with the company. A company name is required. Additional information on this dialog is used for informational and reporting purposes and is not required.

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The following fields are present: Details •

Company—Type the name of the company. The company name uniquely identifies the company, and no two companies can have the same name. If the “Company is locked” box is checked... you will not be able to edit any of the fields.

•

Division—Type the division of the company.

•

Group—Type the company group.

Contact •

Representative—Type the name of the company representative.

•

Address—Type the company’s address.

•

Telephone—Type the telephone number of the company or the company representative.

Company is Locked Checkbox Check this box to prevent editing of the company data. If this box is checked and either a Company Level or Locked Data password has been specified, you will be prompted for the password before you can uncheck this box. Passwords •

Locked Data—Click to specify a password to “lock” all data associated with the company, including all projects, sites, wells, wellbores, scenarios, and cases. To change the locked data password: go to the Well Explorer and right click on the Company, select Properties, select General tab, and then click the Locked Data password button. Enter the old password and the new password (twice), then click OK.

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•

Company Level—Click to specify a password to “lock” only the company data. The company level password is only active if the “Company is locked” box is checked on the Company Properties > General tab.

Real Time Configurations Tab Use the Real-Time Configuration tab to specify real-time mnemonics for log curves that are going into the EDM database via OpenWire for use in real-time Torque and Drag/Hydraulics analyses in WELLPLAN. When you set the real-time configuration properties at the company level, only this company within the database will inherit those real-time properties. You can specify real time configurations for all companies within the database at the database level. Refer to “Properties (Database Level)” on page 66. Real-Time Configuration Properties... You must have correctly specified log mnemonics prior to initiating data transfer using OpenWire. If the mnemonics are not correctly specified, the data transfer will not occur.

Real-Time Mnemonics are Case Sensitive... Real-time mnemonics are case sensitive. Be sure to type them into the Real-Time Configuration tab just as they will appear in the WITSML 1.2 data from your service provider.

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Audit Tab (Company Properties Dialog) Use Audit Tab to display when the company was created and to identify the last modification date as well as the person that modified the data. The Audit tab fields are detailed in “Tracking Data Modifications” on page 61. You can re-open the Company Properties dialog at any time to view or edit the data by right-clicking on the company name in the Well Explorer and selecting Properties from the right-click menu.

Expand All (Company Level) Select this command to expand all nodes in the Well Explorer below the selected Company.

Collapse All (Company Level) Select this command to collapse all nodes in the Well Explorer below the selected Company.

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Working at the Project Level In the Well Explorer, when you right click on a project, the right click menu displays the following choices: Command

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Description

New Site

Create a new site for the selected project (page 76).

New Attachment

Displays the Attachment Properties dialog. Refer to “New Attachment (Company Level)” on page 70 for more information.

Copy

Copy the selected project data to the Clipboard (page 76).

Paste

Paste copied project information (page 76).

Rename


Delete

Delete the selected project and all associated child information (page 77).

Export

Export the selected project’s hierarchical information to an XML file (page 77).

Properties

View or edit the project properties (page 77).

Expand All

To expand all levels below the project level in the Well Explorer (page 79).

Collapse All

To collapse all levels below the project level in the Well Explorer. (page 79)

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New Site (Project Level) To create a new site, select a project and right-click; select New Site. The Site Properties dialog opens.

The fields and controls on the Site Properties dialog are explained in detail on page 81.

New Attachment (Project Level) Use this dialog to associate a document or picture (Word, Excel, text file, JPG, etc.). The document can be of any type with a recognized extension. Refer to “New Attachment (Company Level)” on page 70 for more information.

Copy (Project Level) Use this command to copy the selected project from the Well Explorer and save it to the Clipboard. This command is disabled if nothing has been selected.

Paste (Project Level) Use this command to paste (insert) the contents of the Clipboard at the location currently selected in the Well Explorer. In order for this function to be effective you must have Copied (saved) project data to the Clipboard.

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Rename (Project Level) Use this command to rename the item. You can also rename the data hierarchy item by highlighting it and the clicking once on it. Type the new name in the box that appears around the current name.

Delete (Project Level) Use this command to remove the selected project from the database. A confirmation box will open, asking if you are sure you want to delete the project and all its associated data. Click Yes or No, as appropriate.

Export (Project Level) Use this command to export the selected Project’s data in XML format. Includes the hierarchical information above and any child information associated with the Project. A dialog will open, allowing you to supply a directory and filename for the XML file.

Properties (Project Level) Selecting this command allows you to view or edit Project properties. The Project Properties dialog opens.

Project Properties Dialog The Project Properties dialog is used to create a new project and to provide information regarding creation and modification of the project. This dialog contains two tabs: General and Audit.

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General Tab (Project Properties Dialog) Use to specify a unique project name that identifies the project, and to provide additional information related to the project. This tab is also used to lock the project and/or associated data to protect against undesired changes to the data associated with the project. A project name is required. Additional information on this dialog is used for informational and reporting purposes and is not required. The following fields are present: Details •

Project—Type the name of the project. Project names must be unique within a company. If the “Project is locked” box is checked... you will not be able to edit any of the fields.

•

Description—Type a description of the project.

•

System Datum Description drop-down list—Select a system datum from the drop-down list or type a new datum. The system datum describes absolute zero height or depth for the project, and is the depth from which all wellbore depths are measured.

•

Elevation —This value indicates where the System Datum is relative to Mean Sea Level. For example, if you selected Lowest Astronomical Tide, the value would be negative because LAT would be below MSL. If you select Mean Sea Level, the Elevation field below is grayed out.

Project is Locked Checkbox Check this box to prevent editing of the project data. If this box is checked and a Locked Data password has been specified, you will be prompted for the password before you can uncheck this box. (See “Data Locking” on page 36 for details on data locking.)

Audit Tab (Project Properties Dialog) Use Audit Tab to display when the project was created and to identify the last modification date as well as the person that modified the data.

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The Audit tab fields are detailed in “Tracking Data Modifications” on page 61. You can re-open the Project Properties dialog at any time to view or edit the data by right-clicking on the Project name in the Well Explorer and selecting Properties from the right-click menu.

Expand All (Project Level) Select this command to expand all nodes in the Well Explorer below the selected Project.

Collapse All (Project Level) Select this command to collapse all nodes in the Well Explorer below the selected Project.

Working at the Site Level In the Well Explorer, when you right click on a site, the right click menu displays the following choices: Command

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Description

New Well

Create a new well for the selected site (page 80).

New Attachment


Copy

Copy the selected site data to the Clipboard (page 81).

Paste

Paste copied site information (page 81).

Rename


Delete

Delete the selected site and all associated child information (page 81).

Export

Export the selected site’s hierarchical information to an XML file (page 81).

Properties

View or edit the site properties (page 81).

Expand All

To expand all levels below the site level in the Well Explorer (page 84).

Collapse All


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New Well (Site Level) To create a new well, select a site and right-click; select New Well. The Well Properties dialog opens.

The fields and controls on the Well Properties dialog are explained in detail on page 87.

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New Attachment (Site Level) Use this dialog to associate a document or picture (Word, Excel, text file, JPG, etc.). The document can be of any type with a recognized extension. Refer to “New Attachment (Company Level)” on page 70 for more information.

Copy (Site Level) Use this command to copy the selected site from the Well Explorer and save it to the Clipboard.

Paste (Site Level) Use this command to paste (insert) the contents of the Clipboard at the location currently selected in the Well Explorer. In order for this function to be effective you must have Copied (saved) site data to the Clipboard.

Rename (Site Level) Use this command to rename the item. You can also rename the data hierarchy item by highlighting it and the clicking once on it. Type the new name in the box that appears around the current name.

Delete (Site Level) Use this command to remove the selected site from the database. A confirmation box will open, asking if you are sure you want to delete the site and all its associated data. Click Yes or No, as appropriate.

Export (Site Level) Use this command to export the selected Site’s data in XML format. Includes the hierarchical information above and any child information associated with the Site. A dialog will open, allowing you to supply a directory and filename for the XML file.

Properties (Site Level) Selecting this command allows you to view or edit Site properties. The Site Properties dialog opens.

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Site Properties Dialog The Site Properties dialog is used to create a new site and to provide information regarding creation and modification of the site.

General Tab (Site Properties Dialog) Use to specify a unique site name that identifies the site, and to provide additional information related to the site. This tab is also used to lock the site and/or associated data to protect against undesired changes to the data associated with the site. A site name is required. Additional information on this dialog is used for informational and reporting purposes and is not required. The following fields are present: Details •

Site—Type the name of the site. Site names must be unique within a project. The site name should not be the rig name because rigs are mobile. The site is not mobile. If the “Site is locked” box is checked... you will not be able to edit any of the fields.

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•

District—Type the district information for the site.

•

Block—Type the block for the site.

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Security •

Tight Group Name - This is the security designation for this Site, based on the current user’s access rights. UNRESTRICTED is the default. Be careful - if you restrict this field, certain users will not be able to view this Site. Tight groups are created in the EDM Administration Utility through the EDM Security plug-in. They are assigned in the Well Explorer at the site or well level.

Azimuth Reference •

North Reference - Indicate whether azimuth is specified from True North or Grid North.

Site is Locked Checkbox Check this box to prevent editing of the site data. If this box is checked and a Locked Data password has been specified, you will be prompted for the password before you can uncheck this box. (See “Data Locking” on page 36 for details on data locking.)

Location Tab (Site Properties Dialog) Use this Tab to specify site location information. All information on this tab is optional, and is used for general information and reporting purposes.

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Location •

Lease Name.—Type the name of the lease where the well is located.

•

County—Type the county where the well is located.

•

State/Province—Type the state or province where the well is located.

•

Country—Type the country where the well is located.

Audit Tab (Project Properties Dialog) Use Audit Tab to display when the site was created and to identify the last modification date as well as the person that modified the data. The Audit tab fields are detailed in “Tracking Data Modifications” on page 61. You can re-open the Site Properties dialog at any time to view or edit the data by right-clicking on the Site name in the Well Explorer and selecting Properties from the right-click menu.

Expand All (Site Level) Select this command to expand all nodes in the Well Explorer below the selected Site.

Collapse All (Site Level) Select this command to collapse all nodes in the Well Explorer below the selected Site.

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Working at the Well Level In the Well Explorer, when you right click on a well, the right click menu displays the following choices: Command

Description

New Wellbore

Create a new wellbore for the selected well (page 85).

New Attachment


Copy

Copy the selected well data, and all associated data, to the Clipboard (page 86).

Paste

Paste copied well information, including all associated data (page 86).

Rename


Delete

Delete the selected well and all associated child information (page 87).

Export

Export the selected well hierarchical information to an XML file (page 87).

Properties

View or edit the well properties (page 87).

Expand All

To expand all levels below the well level in the Well Explorer (page 92).

Collapse All


New Wellbore (Well Level) To create a new wellbore, select a well and click New Wellbore. The

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Wellbore Properties dialog opens.

The fields and controls on the Wellbore Properties dialog are explained in detail on page 95.

New Attachment (Well Level) Use this dialog to associate a document or picture (Word, Excel, text file, JPG, etc.). The document can be of any type with a recognized extension. Refer to “New Attachment (Company Level)” on page 70 for more information.

Copy (Well Level) Use this command to copy the selected well from the Well Explorer and save it to the Clipboard.

Paste (Well Level) Use this command to paste (insert) the contents of the Clipboard at the location currently selected in the Well Explorer. In order for this function to be effective you must have Copied (saved) well data to the Clipboard.

Rename (Well Level) Use this command to rename the item. You can also rename the data hierarchy item by highlighting it and the clicking once on it. Type the new name in the box that appears around the current name.

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Delete (Well Level) Use this command to remove the selected well from the database. A confirmation box will open, asking if you are sure you want to delete the well and all its associated data. Click Yes or No, as appropriate.

Export (Well Level) Use this command to export the selected Well’s data in XML format. Includes the hierarchical information above and any child information associated with the Well. A dialog will open, allowing you to supply a directory and filename for the XML file.

Properties (Well Level) Selecting this command allows you to view or edit Well properties. The Well Properties dialog opens.

Well Properties Dialog The Well Properties dialog is used to create a new well and to provide information regarding creation and modification of the well. This dialog contains the tabs: General, Depth Reference, and Audit.

General Tab (Well Properties Dialog) Use to specify a unique well name that identifies the well, and to provide additional information related to the well. This tab is also used to select the unit system, lock the well and/or associated data to protect against undesired changes to the data associated with the well. A well name is required. Additional information on this dialog is used for informational and reporting purposes and is not required.

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Well (Common)—Type the name the well is commonly known by. This name will be used to identify the well using this software. If the “Well is locked” box is checked... you will not be able to edit any of the fields.

•

Well (Legal)—Type the legal name of the well.

•

Description—Type a short description of the well.

•

Location String —Type, edit or view a short description of the geographic description.

Unique Well Identifier

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•

U.W.I.—Type the Universal Well identifier for the well.

•

Type—from the drop-down list, select the type of U.W.I: API, HES/TKT, IODAS, etc.

•

Well No.—Type the well number. WELLPLAN

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Security z

Tight Group Name - This is the security designation for this Site, based on the current user’s access rights. UNRESTRICTED is the default. Be careful - if you restrict this field, certain users will not be able to view this Site. Tight groups are created in the EDM Administration Utility through the EDM Security plug-in. They are assigned in the Well Explorer at the site or well level.

Active Unit System z

Well Units - Select the preferred well units for this well. When a Design or Case is opened below this Well level, those units will be used. You may choose from API or SI, plus any custom-defined unit systems. Note that once you hit Apply, the well units you selected will be applied to all designs and cases under that well, whether they are open or not.

Well is Locked Checkbox Check this box to prevent editing of the well data. If this box is checked and a Locked Data password has been specified, you will be prompted for the password before you can uncheck this box. (See “Data Locking” on page 36 for details on data locking.)

Depth Reference Tab (Well Properties Dialog) Use this Tab to specify datums for use in defining wellbore datums.

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Elevations above, Depths below: [System Datum] This read-only label indicates what the current System Datum is, and states that all elevations are measured ABOVE the System datum, and all depths are measured BELOW the System datum. (The System datum is specified on the General Tab (Project Properties).) A drop-down list box below the label contains all defined Depth Reference datums. Select the Depth Reference datum you want to use to view and calculate data. If you do not specify a Depth Reference datum here, a "Default Datum" with zero elevation above System datum will be used. Information about each datum includes: z

Datum - Type, edit or view the name of the datum.

z

Default - When checked on, indicates that this is the default datum. All Designs created below this Well will inherit the default datum.

z

Elevation - Type, edit or view the elevation above the System Datum (this must be a positive number). Note that if you have a design associated with this datum, you cannot edit this field. If no design is associated with this datum, you can edit the elevation.

z

Rig Name - Type, edit, or view the name of the rig.

z

Date - Type the date the datum was created. The program uses the date field to determine which is the newest datum, and then uses that datum as the default for new wellbores.

Configuration z

For a Land well - If the well is a land well, type the value for the Ground Elevation above the System Datum (must be a positive number). Leave Offshore unchecked.

z

For an Offshore well - If the well is an offshore well: • Check the Offshore checkbox to indicate it is an offshore well. • Type the Water Depth (MSL to mudline). This is the column of water. • Type the Wellhead Elevation (positive above the System Datum).

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Chapter 3: Using the Well Explorer z

For an Offshore well that is Subsea - If the well is an offshore well subsea: • Check the Offshore checkbox. • Check the Subsea checkbox (Offshore must be checked before this option becomes available). • Type the Water Depth (MSL to mudline). This is the column of water. • Type the Wellhead Depth. (positive below the System Datum specified on the General Tab (Project Properties)).

Summary In the Summary area, a graphic depicts the selected configuration (onshore, offshore, or offshore subsea), and displays current values. The following values are calculated and/or displayed: z

Datum - This is the default datum selected in the Well Properties/Depth Reference dialog.

z

Datum Elevation - This is the elevation of the default datum above the System Datum.

z

Air Gap - Air Gap measured to MSL is calculated and displayed. Air Gap is the distance from ground level/sea level to the rig floor, and is used in some calculations for hydrostatic head. Air Gap is always positive. The application calculates Air Gap as follows: • (Air Gap, offshore wells) = Datum Elevation – Elevation (of the System Datum relative to Mean Sea Level). • (Air Gap, land wells) = Datum Elevation – Ground Level (relative to the System Datum).

Elevation is set in the Project Properties > General dialog. Ground Level is set in the Well Properties > Depth Reference dialog. Datum Elevation is the elevation for the Depth Reference Datum. Datum Elevation is always positive. If you change the datum selection, the Air Gap updates automatically. Note that if you change the datum and it causes a negative air gap to be calculated, a warning message will appear, informing you that you cannot select this datum.

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[System Datum] - Display the current System Datum. Mudline Depth (MSL) - (Offshore only) Display the distance from MSL to the sea bed, which is Water Depth – Elevation (System Datum offset from MSL, which is set in the Project Properties dialog). Mudline TVD - (Offshore only) Display the distance from the Depth Reference Datum to the sea bed (datum Elevation + Water Depth).

Audit Tab (Well Properties Dialog) Use Audit Tab to display when the well was created and to identify the last modification date as well as the person that modified the data. The Audit tab fields are detailed in “Tracking Data Modifications” on page 61. You can re-open the Well Properties dialog at any time to view or edit the data by right-clicking on the Well name in the Well Explorer and selecting Properties from the right-click menu.

Expand All (Well Level) Select this command to expand all nodes in the Well Explorer below the selected Well.

Collapse All (Well Level) Select this command to collapse all nodes in the Well Explorer below the selected Well.

Working at the Wellbore Level In the Well Explorer, when you right click on a wellbore, the right click menu displays the following choices: Command New Design

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Description Create a new design for the selected wellbore (page 93).

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New Design/Case from OpenWells

Create a design or case based on an OpenWells report.

New Attachment


Copy

Copy the selected wellbore data to the Clipboard (page 94).

Paste

Paste copied wellbore information (page 94).

Rename


Delete

Delete the selected wellbore and all associated child information (page 95).

Export

Export the selected wellbore’s hierarchical information to an XML file (page 95).

Properties

View or edit the wellbore properties (page 95).

Expand All

To expand all levels below the wellbore level in the Well Explorer (page 97).

Collapse All


New Design (Wellbore Level) To create a new design, select a wellbore and right-click; select New Design. The Design Properties dialog opens.

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The fields and controls on the Design Properties dialog are explained in detail on page 99.

New Design/Case from OpenWells Use this dialog to bring a selected Casing Report, Fluids Report, or Daily Operations Report over from OpenWells to WELLPLAN and save the data as a case.

New Attachment (Wellbore Level) Use this dialog to associate a document or picture (Word, Excel, text file, JPG, etc.). The document can be of any type with a recognized extension. Refer to “New Attachment (Company Level)” on page 70 for more information.

Cut (Wellbore Level) Use this command to cut the selected wellbore from the Well Explorer and save it to the clipboard.

Copy (Wellbore Level) Use this command to copy the selected wellbore from the Well Explorer and save it to the Clipboard.

Paste (Wellbore Level) Use this command to paste (insert) the contents of the Clipboard at the location currently selected in the Well Explorer. In order for this function to be effective you must have Copied (saved) wellbore data to the Clipboard.

Rename (Wellbore Level) Use this command to rename the item. You can also rename the data hierarchy item by highlighting it and the clicking once on it. Type the new name in the box that appears around the current name.

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Delete (Wellbore Level) Use this command to remove the selected wellbore from the database. A confirmation box will open, asking if you are sure you want to delete the wellbore and all its associated data. Click Yes or No, as appropriate.

Export (Wellbore Level) Use this command to export the selected Wellbore’s data in XML format. Includes the hierarchical information above and any child information associated with the Wellbore. A dialog will open, allowing you to supply a directory and filename for the XML file.

Properties (Wellbore Level) Selecting this command allows you to view or edit Wellbore properties. The Wellbore Properties dialog opens.

Wellbore Properties Dialog The Wellbore Properties dialog is used to create a new wellbore and to provide information regarding creation and modification of the wellbore. This dialog contains two tabs: General and Audit.

General Tab (Wellbore Properties Dialog) Use to specify a unique wellbore name that identifies the wellbore, and to provide additional information related to the wellbore. This tab is also used to lock the wellbore and/or associated data to protect against undesired changes to the data associated with the wellbore. A wellbore name is required. Additional information on this dialog is used for informational and reporting purposes and is not required.

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Wellbore—Type the name that will be used to identify the wellbore. The name must be unique. If the “Wellbore is locked” box is checked... you will not be able to edit any of the fields.

Sidetrack from an Existing Wellbore •

Parent Wellbore—If the wellbore is a sidetrack, select the wellbore that contains the starting point.

Wellbore is locked checkbox Check this box to prevent editing of the wellbore data. If this box is checked and a Locked Data password has been specified, you will be prompted for the password before you can uncheck this box. (See “Data Locking” on page 36 for details on data locking.)

Audit Tab (Wellbore Properties Dialog) Use Audit Tab to display when the wellbore was created and to identify the last modification date as well as the person that modified the data. The Audit tab fields are detailed in “Tracking Data Modifications” on page 61.

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You can re-open the Wellbore Properties dialog at any time to view or edit the data by right-clicking on the Wellbore name in the Well Explorer and selecting Properties from the right-click menu.

Expand All (Wellbore Level) Select this command to expand all nodes in the Well Explorer below the selected wellbore.

Collapse All (Wellbore Level) Select this command to collapse all nodes in the Well Explorer below the selected Wellbore.

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Working at the Design Level In the Well Explorer, when you right click on a design, the right click menu displays the following choices: Command

Description

New Case

(WELLPLAN only) Create a new case for the selected design (page 98).

New Attachment


Copy

Copy the selected design data to the Clipboard (page 99).

Paste

Paste copied design information (page 99).

Rename


Delete

Delete the selected design and all associated child information (page 99).

Export

Export the selected design’s hierarchical information to an XML file (page 99).

Properties

View or edit the design properties (page 100).

Expand All

To expand all levels below the design level in the Well Explorer (page 102).

Collapse All


New Case (Design Level) To create a new case, select a design and right-click; select New Case. The Case Properties dialog opens.

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The fields and controls on the Case Properties dialog are explained in detail on page 104.

New Attachment (Design Level) Use this dialog to associate a document or picture (Word, Excel, text file, JPG, etc.). The document can be of any type with a recognized extension. Refer to “New Attachment (Company Level)” on page 70 for more information.

Copy (Design Level) Use this command to copy the selected design from the Well Explorer and save it to the Clipboard.

Paste (Design Level) Use this command to paste (insert) the contents of the Clipboard at the location currently selected in the Well Explorer. In order for this function to be effective you must have Copied (saved) design data to the Clipboard.

Rename (Design Level) Use this command to rename the item. You can also rename the data hierarchy item by highlighting it and the clicking once on it. Type the new name in the box that appears around the current name.

Delete (Design Level) Use this command to remove the selected design from the database. A confirmation box will open, asking if you are sure you want to delete the design and all its associated data. Click Yes or No, as appropriate.

Export (Design Level) Use this command to export the selected Design’s data in XML format. Includes the hierarchical information above and any child information associated with the Design. A dialog will open, allowing you to supply a directory and filename for the XML file.

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Properties (Design Level) Selecting this command allows you to view or edit Design properties. The Design Properties dialog opens.

Design Properties Dialog The Design Properties dialog is used to create a new design and to provide information regarding creation and modification of the design. This dialog contains two tabs: General and Audit.

General Tab (Design Properties Dialog) Use to specify a unique design name that identifies the design, and to provide additional information related to the design. This tab is also used to lock the design and/or associated data to protect against undesired changes to the data associated with the design. A design name is required. Additional information on this dialog is used for informational and reporting purposes and is not required.

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Design—Type the name that will be used to identify the design. The name must be unique. If the “Design is locked” box is checked... you will not be able to edit any of the fields.

•

Version—Type the version of the design.

•

Phase—Select the phase of the design from the drop-down list box (Prototype, Planned or Actual). The list of phases that appear in the combo box is filtered; you can only have one design marked as "Planned" and one marked as "Actual." The Planned or Actual option is removed from the drop-down list box if another design for the same Wellbore already has it set. You can have as many Prototype (the default) designs as desired.

•

Effective Date—Select the date from the drop-down list box. A calendar dialog will open. Use the arrow buttons on the calendar dialog to move to the desired month, then click on the day. The date you selected will populate the field.

Click arrows to change to desired month.

Click on the desired day

Depth Reference Information Select the Depth Reference datum you want to use for this Design from the drop-down list of Depth Reference datums that were defined at the Well level. All other fields are display-only or calculated:

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Design is locked checkbox Check this box to prevent editing of the design data. If this box is checked and a Locked Data password has been specified, you will be prompted for the password before you can uncheck this box. (See “Data Locking” on page 36 for details on data locking.)

Audit Tab (Design Properties Dialog) Use Audit Tab to display when the design was created and to identify the last modification date as well as the person that modified the data. The Audit tab fields are detailed in “Tracking Data Modifications” on page 61. You can re-open the Design Properties dialog at any time to view or edit the data by right-clicking on the Design name in the Well Explorer and selecting Properties from the right-click menu.

Expand All (Design Level) Select this command to expand all nodes in the Well Explorer below the selected design.

Collapse All (Design Level) Select this command to collapse all nodes in the Well Explorer below the selected Well.

Working at the Case Level (WELLPLAN Only) In the Well Explorer, when you right click on a case, the right click menu displays the following choices: Command

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Description

Open

Open the selected case (page 103).

Close

Close the currently open case (page 103).

Clear Active Workspace

Clear the active workspace (page 103).

New Attachment


Copy

Copy the selected case data to the Clipboard (page 103).

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Paste

Paste copied case information (page 99).

Rename


Delete

Delete the selected case and all associated child information (page 104).

Export

Export the selected case’s hierarchical information to an XML file (page 104).

Properties

View or edit the case properties (page 104).

Open (Case Level) Use this command to open the selected Case.

Close (Case Level) Use this command to close the currently open Case. When prompted, click Yes or No to indicate whether or not to save changes made to the case.

Clear Active Workspace (Case Level) Use this command to clear the active workspace. The active workspace is stored in the database and contains the configuration and layout of the tabs. If you are using a Module Workspace, this option will not remove the workspace. If you no longer want to use the Module Workspace, you must right-click on it in the Well Explorer, and select Delete from the right-click menu.

New Attachment (Case Level) Use this dialog to associate a document or picture (Word, Excel, text file, JPG, etc.). The document can be of any type with a recognized extension. Refer to “New Attachment (Company Level)” on page 70 for more information.

Copy (Case Level) Use this command to copy the selected case from the Well Explorer and save it to the Clipboard.

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Paste (Case Level) Use this command to paste (insert) the contents of the Clipboard at the location currently selected in the Well Explorer. In order for this function to be effective you must have Copied (saved) design data to the Clipboard.

Rename (Case Level) Use this command to rename the item. You can also rename the data hierarchy item by highlighting it and the clicking once on it. Type the new name in the box that appears around the current name.

Delete (Case Level) Use this command to remove the selected case from the database. A confirmation box will open, asking if you are sure you want to delete the case and all its associated data. Click Yes or No, as appropriate.

Export (Case Level) Use this command to export the selected Case’s data in XML format. Includes the hierarchical information above and any child information associated with the Case. A dialog will open, allowing you to supply a directory and filename for the XML file.

Properties (Case Level) Selecting this command allows you to view or edit Case properties. The Case Properties dialog opens.

Case Properties Dialog The Case Properties dialog is used to create a new case and to provide information regarding creation and modification of the case. This dialog contains four tabs: General, Job, Contact, and Audit.

General Tab (Case Properties Dialog) Use to specify a unique case name that identifies the case, and to provide additional information related to the case. This tab is also used to lock the case and/or associated data to protect against undesired

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changes to the data associated with the case. A case name is required. Additional information on this dialog is used for informational and reporting purposes and is not required.


Case—Type the name that will be used to identify the case. The name must be unique. If the “Case is locked” box is checked... you will not be able to edit any of the fields.

•

Description—Type a description of the case.

Case is locked checkbox Check this box to prevent editing of the case data. If this box is checked and a Locked Data password has been specified, you will be prompted for the password before you can uncheck this box. (See “Data Locking” on page 36 for details on data locking.)

Job Tab (Case Properties Dialog) Use to specify information about the case, particularly for cementing jobs. Additional information on this dialog is used for informational and reporting purposes and is not required.

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The following fields are present: Job Details •

Date—You must select the date from the calendar. To enable the calendar, click the downward arrow or press F4. A calendar dialog will open. Use the arrow buttons on the calendar dialog to move to the desired month, then click on the day. The date you selected will populate the field. If this case is a cement job, this will be the date the cement job was run.

Click arrows to change to desired month.

Click on the desired day

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•

Description—Type a short description of the job.

•

Pipe Size—Type the pipe size. Although the pipe size can be specified independent of the String Editor, the pipe size will default from the outside diameter of the first casing listed in the String Editor.

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Contact Tab (Case Properties Dialog) Use to specify contact information about the case. Additional information on this dialog is used for informational and reporting purposes and is not required.

The following fields are present: Contact Details •

Company—Type the name of the company associated with this case.

•

Representative—Type the name of the person to contact about this case within the company.

•

Address—Type the address of the representative or the address of the company for this case.

•

Telephone—Type the telephone number for the representative or the company.

Audit Tab (Case Properties Dialog) Use Audit Tab to display when the case was created and to identify the last modification date as well as the person that modified the data. The Audit tab fields are detailed in “Tracking Data Modifications” on page 61.

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You can re-open the Case Properties dialog at any time to view or edit the data by right-clicking on the Case name in the Well Explorer and selecting Properties from the right-click menu.

Working With Design- and Case-Associated Components There are several data components that are associated at either the Design or Case level; they are used to define the drilling problem that you want to analyze. Associated components include: • • • • • • •

Wellpaths Pore Pressure Groups Fracture Gradient Groups Geothermal Gradient Groups Hole Section Groups Assemblies Fluids

The components listed above are associated to a Design or a Case. One component can be associated to multiple designs or cases. You can copy and paste components from one case to another using the item's right-click menu. For conceptual information and associated rules, see “Associated Components” on page 32 and “Rules for Associating Components” on page 34.

About Associated Items and Well Explorer All of these associated items, with the exception of fluids, are automatically created and associated ("linked") by Well Explorer to the design or case. (You cannot manually create or link these items.) Fluids can be created/linked in WELLPLAN only, using the Fluid Editor. However, all these items are visible in Well Explorer so that you can copy and paste them using the right-click menu. For example, when you copy a wellpath and paste it into a different design, the wellpath that currently exists for the target design is deleted. Well Explorer replaces the old wellpath with the copy of the new one. Again, fluids are the exception. Only the WELLPLAN Fluid Editor can delete fluids, so after pasting a fluid, the original fluid still exists. The original fluid is no longer linked to anything. This can’t be seen in Well Explorer, but WELLPLAN can access this. Note that if the destination

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case, or the fluid you are trying to replace, is locked, a message appears and the paste is not completed.

Wellpaths A wellpath is a series of survey tool readings that have been observed in the same wellbore and increase with measured depth. All Cases within the same design use the same wellpath.

Pore Pressure Groups A Pore Pressure group is a set of pore pressures that define the pore pressure regime over a depth range from surface to some vertical depth. All Cases within the same design use the same pore pressure.

Fracture Gradient Groups A Fracture Gradient is a set of fracture pressures that define the fracture gradient regime over a depth range from surface to some vertical depth. All Cases within the same design use the same fracture gradient.

Geothermal Gradient Groups A Geothermal Gradient is a set of undisturbed earth temperatures that define the temperatures over a depth range from the surface to some vertical depth. All Cases within the same design use the same geothermal gradient.

Hole Section Groups A Hole Section defines the wellbore as the workstring would see it. For example, a hole section may contain a riser, a casing section, and an open hole section. A hole section can also have a tubing section or a drill pipe section depending on the situation. Multiple cases may use the same hole section or every case can have a different hole section.

Assemblies An Assembly defines the workstring. There are several types of workstrings, including coiled tubing, casing, drillstrings, liners, and tubing strings. Multiple cases may use the same assembly or every case can have a different assembly.

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Fluids A Fluid defines a drilling, cementing, or spacer fluid. A Fluid is linked to a Case and a Case can have more than one fluid linked to it. One fluid can be linked to multiple cases. You can also create a fluid directly in WELLPLAN, using the Fluid Editor.

Creating a New Fluid 1. From the WELLPLAN main menu, select Case > Fluid Editor. The Fluid Editor dialog displays. 2. Click New. A dialog prompts you to provide the fluid name. 3. Specify the name of the fluid and click OK. The Fluid Editor, populated with default data, displays. 4. Enter fluid data as needed. 5. Activate the fluid by selecting it and clicking Activate. 6. Save the Case. 7. Go to the Well Explorer and press F5 go refresh. You should see the fluid is now listed in the Associated Data Viewer for that Case.

Associating a Fluid to a Case You can associate an existing fluid to a case by highlighting the fluid and using the right-click menu. On the right-click menu, select Copy. Next, click on the case you want and use the right-click menu to Paste (link) the fluid to the case.

Working With Catalogs Catalogs are used as a selection list to design a casing, tubing, liner or drillstring. Catalogs are not linked to a Design or Case. Read-only catalogs are distributed with the software. Additional catalogs can be created and these catalogs will allow changes. You can copy and paste a catalog (including read-only catalogs) using the right-click menu; copied catalogs are editable and can be customized. Custom catalogs are useful because the catalog content can be customized to the

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available pipes or other drilling products. You can also lock a catalog to prevent changes. You can create, copy, delete, export, and import catalogs, as well as view their properties. Additionally, in WELLPLAN only, you can open, save, or close a catalog. The following catalogs are available: • • • • • • • • • • • • • • • • • • • • • •

Accelerator Bits Casing Shoes Casing/Tubing Casing/Tubing Connectors Coiled Tubing Centralizer Coiled Tubing Drill Collar Drill Pipe Eccentric Stabilizer Heavy Weight Hole Openers Jar Mud Motor Mud Pumps MWD Packers Port Collars/Diverter Subs/Circulating Subs Stabilizer Subs Underreamers

For details about the fields in the various catalogs, see the online Help.

Creating a New Catalog To create a new catalog: 1. In the Well Explorer, right click on the catalog category (Accelerators, Centralizers, etc.) and select New. The Catalog Properties dialog displays. 2. Specify the name of the catalog on the Catalog Properties dialog. You may enter data into the new catalog using the drilling software,

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or the Catalog Editor (to access Catalog Editor, select Start > Programs > Landmark Engineer’s Desktop > Tools > Catalog Editor.)

Copying a Catalog To copy an existing catalog (read-only or otherwise) and paste it as a new, customizable catalog: 1. Right click on the catalog you want to copy and select Copy. 2. Navigate back to the root of the catalog type, and right click; select Paste. 3. The catalog will be copied to this location, and the contents will be editable. By default, the name will be the same as the original, except for the number one appended to the end of the name. This number increments with subsequent copies. To change the default name, right-click on the catalog and select Properties from the right-click menu. In the Properties dialog, type the desired catalog name in the Name field.

Deleting a Catalog You cannot delete catalogs that are locked, and you can never delete API catalogs. Be careful not to delete a catalog other database users may need. To delete a catalog: 1. In the Well Explorer, right-click on the catalog you want to delete and select Delete. 2. You will be asked to confirm the delete; click Yes to proceed. The catalog will be deleted.

Exporting a Catalog A catalog can be exported in XML format. You can then import it into a different database EDM database. 1.

In the Well Explorer, right-click on the catalog you want to export and select Export.

2. A dialog appears, allowing you to provide a directory and filename for the catalog, which will be saved as an XML file.

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3. Click Save to proceed with the export.

Importing a Catalog You can import a catalog that has been exported in XML format from a EDM database. 1.

In the Well Explorer, navigate to the root of the catalog tree and right click; select Import.

2. A dialog appears, allowing you to provide a directory and filename for the catalog, which will be saved as an XML file. 3. Click Save to proceed. The catalog will be imported. File naming... EDM Data Transfer File imports are not supported from paths containing apostrophes or filenames containing apostrophes. Make sure that you do not use apostrophes in filenames or folder names.

Opening a Catalog To open a catalog (WELLPLAN only): 1. In the Well Explorer, select the catalog you want to open and rightclick; select Open. 2. The catalog will open in the main window. You can open a catalog in the Catalog Editor. To do so, select Start > Programs > Landmark Engineer’s Desktop > Tools > Catalog Editor.

Saving a Catalog To save a catalog (WELLPLAN only): 1. With the catalog you want to save open in the main window, go to the Well Explorer and right-click; select Save. 2. The catalog will be saved to the database.

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Closing a Catalog To close a catalog (WELLPLAN only): 1. With the catalog open in the main window, go to the Well Explorer and right-click; select Close. 2. If you have not yet saved the changes, you will be prompted to save before closing. 3. The catalog will be closed.

Catalog Properties Dialog The Properties dialog for ALL catalogs contains the two tabs: General and Audit. These tabs are the same for all catalogs. The example below shows the Properties dialog for an API Drill Collar catalog.

General Tab (Catalog Properties Dialog) Use to specify a unique name that identifies the catalog, and to provide additional information related to the catalog. This tab is also used to lock the catalog to protect against undesired changes to the data associated with the catalog. A catalog name is required.

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The following fields are present on the General tab for all Catalog Properties dialogs: Details •

Name—Type the name of the catalog. This must be unique.

•

Description—Type a short description of the catalog.

Catalog is locked checkbox The default catalogs distributed with the software are read-only and locked. (A blue key beside the name of the catalog indicates that it is locked.) The contents of the default catalogs cannot be changed. Catalogs are exempt from the locked data password.

Audit Tab (Catalog Properties Dialog) Use Audit Tab to display when the catalog was created and to identify the last modification date as well as the person that modified the data. The Audit tab fields are detailed in “Tracking Data Modifications” on page 61. You can re-open the Properties dialog for the catalog at any time to view or edit the data by right-clicking on the catalog name in the Well Explorer and selecting Properties from the right-click menu.

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Chapter 4

Concepts and Tools Overview In this chapter, you will become familiar with using basic WELLPLAN features. In this section of the course, you will become familiar with: Accessing the online documentation and tools Menus and menu bars Toolbars Configuring units Converting MD to TVD, or TVD to MD using the Convert Depth dialog Converting Field or Cell Units using the Convert Unit dialog Defining tubular properties Workspaces Libraries Using the Data Dictionary to change field names and descriptions Viewing and configuring plots Accessing the online help

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Chapter 4: Concepts and Tools

Accessing Online Documentation and Tools WELLPLAN is installed with online documentation to assist you with using the product. This documentation can be found by using the Start Menu. The default installation will create a program group titled Landmark Engineer’s Desktop 2003.11. From there, you can select the software you want to use, the Documentation sub-group, or the Tools sub-group. Using the Documentation sub-group, you may select:

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Help - This selection provides access to the online help for all the EDT software applications. The online help is also accessible from all windows, and dialogs in the software.

z

Release Notes - This selection provides access to the release notes for all the EDT software applications. Release notes provide useful information about the current release, including: new features, bug fixes, known problems, and how to get support when you need it.

z

User Guides - This selection provides access to the EDT Installation Guide.

z

Integrated EDM Workflows - There are several documented workflows involving WELLPLAN. Refer to this document for suggested workflow steps.

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Using the Main Window The WELLPLAN Main Window is shown below. In this example, the Well Explorer is displayed on the left. The Well Schematic on the right is not displayed because the Case data has yet to be specified. In many cases, data entry and reviewing analysis are performed in separate windows that you can view simultaneously within the Main Window. There are several distinct areas within the Main Window as shown in the following figure. Title Bar

Wizard Toolbar Standard Toolbar

Module Toolbar Window Title Bar

Graphic Toolbar

Menu Bar

Associated Data Viewer

Tabs

Status Bar

Using the Well Explorer For information on the Well Explorer, refer to “Using the Well Explorer” on page 55.

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Using the Menu Bar After a case has been created or opened, the menu bar has more selections. We will begin to look at these options more closely The menu bar provides access to all tools available within the software. It is organized as follows: Select...

To...

File

Use the File Menu to create new companies, projects, wells, wellbores, designs, cases and catalogs, delete projects, wells, cases and catalogs, access import/export functions, access print functions, and exit WELLPLAN.

Edit

Use the Edit Menu to undo changes; cut, copy, and paste information, and also specify or view information related to the active window’s contents. Use the Report Header Setup option to specify the title to use on the output, and to specify the logo (bitmap) to place on the output.

Modules

Use the Modules Menu to access the various WELLPLAN modules, including: Torque Drag, Hydraulics, Well Control, Surge, Cementing-OptiCem, Critical Speed, Bottom Hole Assembly, Stuck Pipe and Notebook.

Case

Use the Case Menu to enter data that will be used for all analysis modes associated with the selected analysis module. Therefore, the contents of the Case Menu will vary depending on the module chosen (i.e. Torque Drag, Hydraulics, Surge, Well Control, etc.). The Case Menu has dialogs and spreadsheets for gathering information pertaining to the case you are defining. Most of the information entered in this menu’s options will be used for many or possibly all modules and module analysis modes. Some Case menu options are only available for gathering information pertaining to specific WELLPLAN modules. Also, the menu options available may vary by analysis mode. You must enter information on all dialogs visible in the Case menu for the selected analysis mode before you can proceed with the analysis.

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Select...

To...

Parameter

Use the Parameter Menu to enter analysis parameters for the chosen analysis mode. The contents of the Parameter Menu vary depending on the analysis mode chosen.The Parameter Menu will be discussed in detail later in the course.

Hole Section

The Hole Section Menu is only available when the Case > Hole Section Editor is active. Use this menu to access catalog details for a hole section.

String

The String Menu is only available when the Case > String Editor is active. Use this menu to display the catalog or specific information about a workstring component.

View

The View menu is used to calculate results or toggle auto-calculation; toggle on and off several window components; display plots, tables, and reports for analysis; and display schematics, fluid plots, and survey plots.

Tools

The Tools Menu is used to add, remove, edit, and select unit systems. You can also use this menu to specify grade, material, and class tubular properties.

Help

Access the online Help, current version info.

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Working With Units Configuring Unit Systems Use the Tools > Unit System dialog to add, remove, edit, and switch unit systems. The unit system for the design is stored at the Well level. All unit systems are stored in the database. The Unit System dialog always contains two or more tabs arranged along its upper left corner, one for each available unit system stored in the database. The two left-most tabs are always API and SI. When this dialog is opened, the tab containing the unit system associated with the active well highlights. Most numerical dialog fields and spreadsheet cells are associated with a physical parameter such as depth, stress, or temperature, and each physical parameter is expressed in a unit. To switch to a different unit system, simply select another tab and then click OK. The status bar at the bottom of the screen displays the name of the unit system currently in use. Unit system is set at the Well level, and affects all wellbores, designs, and cases below it.

Active unit set is selected using the drop-down list. Click New to create a unit system.

Click Edit to edit a unit set you have created. You can not edit the API or SI unit sets. Click Delete to delete a unit set that you have created.

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Converting MD to TVD, or TVD to MD Use the Convert Depth dialog to convert between measured depth (MD) (TVD). All conversions are based on the deviation specified in the Case > Wellpath > Wellpath Editor. To access the Convert Depth dialog, press the F9 key while using any spreadsheet or dialog within WELLPLAN, except for the dialogs associated with the Well Explorer (Company properties, well properties, etc.) Using the Convert Depth Dialog will not change your data... The converted value is view-only, and therefore will not be written to the cell/field after the dialog is closed.

Using the Convert Depth Dialog: 1. Access a spreadsheet of dialog within WELLPLAN. For this example, access Case > Hole Section Editor. 2. Click in the Hole Section Depth (MD) field, or any other field. 3. Press F9. The Convert Depth dialog is displayed. 4. Type a depth into the MD field to convert MD to TVD, or type the depth into the TVD field to convert a TVD to MD. 5. Click the MD to TVD if you are converting MD to TVD button, or click the TVD to MD button if you are converting TVD to MD. 6. If you were converting MD to TVD, the TVD associated with the specified MD is displayed. Otherwise, the MD associated with the specified TVD is displayed. 7. Click the X in the upper-right corner of the dialog to close the Convert Depth dialog.

Converting Field or Cell Units Use this dialog to view data entered into a field or cell in another unit. This process does not change the unit system. To change the unit system, use Tools > Unit Systems.

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Access the Convert Unit dialog by pressing F4 when an editable spreadsheet cell or dialog field is selected.

Using the Units Dialog: 1. Access a spreadsheet of dialog within WELLPLAN. For this example, access Case > String Editor. 2. Click in an OD field, or any other field. For this example, click in the OD field.

3. Press F4. The Convert Units dialog is displayed. Note that the default value and unit is based on the entry in the String Editor.

4. Select another unit and the converted value will be displayed. Click OK to close the dialog. The value in the String Editor will not be changed.

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Defining Tubular Temperature Deration, Grade, Material and Class Tubular properties can be changed using the Tools menu. Tubular properties include temperature deration, material, grade and class. These properties are used to describe the well tubulars and other components used in the wellbore and workstring editors. You can add additional properties, edit existing properties, or delete entire rows as you can with any spreadsheet in the system.

Temperature Deration Use the Tools > Tubular Properties > Temperature Deration spreadsheet to specify the temperature deration schedules for materials by specifying temperatures and their associated yield correction factors.

Material Use the Tools > Tubular Properties > Material dialog to compile a list of material types and associated properties. Material is used to define the density of the material, Young’s modulus and Poisson’s ratio for tubular and other components. This list is used as a selection list while defining a grade on the Tools > Tubular Properties > Grade spreadsheet. You must enter a unique name to identify the material. To define this material, enter a description of the material, and the Young’s Modulus, Poisson’s Ratio, and density of the material.

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To insert a row add to the bottom of the existing list. You must enter data in each column.

Tubular Grades The Tools > Tubular Properties > Grade spreadsheet consists of two spreadsheets. Use the grades section of the spreadsheet to compile a list of grades and associated properties. This list is used as a selection list while defining a component using catalogs. Use the Section Types dropdown list to select the section types that have this material grade. You must enter a unique name to identify the grade. To define the grade, specify the material, minimum yield strength, fatigue endurance limit, and ultimate tensile strength. Rows cannot be inserted into or deleted from the Grades section of the spreadsheet.

To Insert a Row into the Section Types List: Enter data in the last blank row of the list, or highlight a row in the list and use Edit > Insert Row(s).

To Delete a Row in the Section Types List: Highlight the row in the list you want to delete and use Edit > Delete Row(s).

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The section types listed can use the selected grade.

Select section type from this drop-down list.

Class Use Tools > Tubular Properties > Class dialog to compile a list of tubular classes and associated properties. This list is used as a selection list while defining a component using catalogs. You must enter a unique name to identify the class. To define the class, you must specify the wall thickness, and enter a short description. The wall thickness percentage is used to calculate the existing outside diameter of the tubular using the Pipe Wall Thickness Modification Due to Pipe Class Calculations.

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To insert a row add to the bottom of the existing list. You must enter data in each column

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Using Halliburton Cementing Tables Click Tools > Halliburton Cementing Tables to access an online version of the traditional Redbook. You can use the Cementing Tables to determine hole capacities, tubular/casing displacements, tubing/casing strength and dimensions, volumes between tubing and casing, etc.

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Configuring Sound Effects Use Tools > Sound Effects to toggle (on or off) any sound effects related to WELLPLAN program operation. When the menu option is checked, sound effects are on. When the menu option is unchecked, sound effects are off.

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Using the Online Help The Help Menu has several available options. Help can be accessed by pressing the F1 key, selecting Help from the Menu bar, or by clicking the Help button available on many dialogs. Contents displays the online help topics grouped together in a logical format. Use About WELLPLAN to determine what version and build number you are using. This is very helpful information if you are contacting WELLPLAN support.

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Using Tool Bars After a case has been created or opened, you can see that the toolbar choices on the Main Window have been expanded. Toolbars have buttons you can use to quickly perform common operations, such as file management commands and engineering functions. There are several toolbars. Each toolbar is outlined by a single line, so you can tell what is included in each toolbar. Toolbars are normally found just below the menu bar, but they can be “undocked” and moved to other areas within the application window. They can also be removed from view using View > Toolbars. Toolbar buttons are grayed out when they are not applicable to what you are currently doing.

Enabling Toolbars Use View > Toolbars command to enable or disable the Standard, Module, Wizard and Graphics toolbars. To enable or disable a toolbar, simply click the appropriate check box, which will either add it or remove it from the screen. Click to turn on the toolbar.

By default, all toolbars are normally displayed directly below the menu bar. Although the print preview toolbar will not be displayed until you select File > Print Preview. However, all toolbars are dockable, which means they can be moved around the screen and adjusted to fit your needs. To move a toolbar, click anywhere on the toolbar’s light grey border and drag it away from its original position. After you release the mouse button, the toolbar resides in a palette window which “floats” above the application frame. After a toolbar has been undecked, it can be moved to another portion of the screen by clicking anywhere in its light gray border, or title bar and then dragging it. To re-dock an undocked toolbar, simply drag it to any edge of the application frame. When the toolbar approaches a valid docking position, its border will suddenly change. At this point, you can release the mouse button. After you release the

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mouse button, the positions of any overlapping toolbars will be adjusted to accommodate the new toolbar.

Using the Standard Toolbar The Standard toolbar provides easy access to common file management and printing commands.

Help

Print Preview Undo

Print

Copy

Cut

Paste

Calculate Auto Calculate

New Open Case

Maximize/Restore

Save Active Case or Catalog

Toggle Status Message Window Well Explorer Recent Bar

Using the Module Toolbar The Module toolbar provides access to the engineering modules. You can also access the engineering modules by using the Modules Menu.

Notebook Well Control

OptiCem - Cementing Critical Speed Bottom Hole Assembly

Hydraulics

Stuck Pipe

Torque Drag

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Using the Graphics Toolbar The Graphics toolbar provides access to graphical functions and is only available when a plot is active in the current window. If the Graphics Toolbar is grey, click once on the plot and the toolbar selections will become available. Refer to “Configuring Plot Properties” on page 138 for more information.

Legend Line

Grid View Data Reader Rescale

Swap Axis

Properties

Turns off the functions enabled by some Graphics toolbar buttons

Using the Wizard Toolbar The Wizard toolbar provides access to analysis modes, and data entry forms. Mode drop-down list to select desired analysis mode.

Wizard drop-down list to guide you through data entry.

Previous Next

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Using Wellpath Plots and Schematics Using Well Schematics The Well Schematics are accessed using View > Schematics. There are three schematics to choose from including full-scale and not-to-scale. The Schematic is a tool to display a graphical image of the active wellbore and workstring defined using the case menu. On the Schematic, the workstring components will be defined, and casing shoes will be indicated. By default the well schematic is displayed when you open a case.

Right-click anywhere on the schematic and select Header On/Off to turn display or remove the heading information.

Riser

Casing

Open hole section

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Viewing Wellpath Plots Several different wellpath plots are available, regardless of the engineering analysis you are performing. These plots include: • • • • • • • • •

Vertical section Plan view Dogleg severity Inclination Azimuth Absolute tortuosity Relative tortuosity Build-plane curvature Walk-plane curvature

Accessing Wellpath Plots Wellpath plots can be accessed by: • •

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Right-click on the Case > Wellpath > Editor and select a survey plot. Similarly, you can right-click on the Case > Wellpath > View w/Interpolation or Case > Wellpath > View w/Tortuosity editors to view the survey plots. Use View > Wellpath Plots and select the desired plot.

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Printing and Print Preview Printing or preview printing of output is very similar to other software you are probably familiar with. Use File > Print to print the current plot or view. Use File > Print Preview to preview the item prior to printing it. Use File > Page Setup to set the margins of the page prior to printing. Use File > Print Setup to select and configure the printer, sand to select the page size and orientation.

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Configuring Plot Properties

Plot toolbar Properties button

Changing Curve Line Properties To alter the appearance of a curve on the plot, click the right mouse button when the cursor is on the curve line. Using the menu that opens, you can hide the line, freeze the line, or change the appearance of the line. When you hide a line, it disappears from the plot. Freeze line is a useful feature for sensitivity analysis. When you freeze the line, and then alter some of the analysis data that the plot is based on, the frozen line will be displayed along with the analysis data.

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Use line properties to change line color, width, and style.

Using Freeze Line Freeze Line is a very useful feature for sensitivity analysis. When a line is “frozen”, you can specify a unique name for the line that will be displayed in the legend. When the analysis data is changed, the frozen line will remain on the plot along with the new curve data. This enables easy comparison of results for sensitivity analysis.

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Using the Plot Properties Tabs This Plot Properties dialog has tabs for customizing the currently active pane or the currently active view within the pane, such as plots or tables. You must have a view currently active before you can select this option. Use the Plot Properties tabs to change many aspects of an active plot or table.

Accessing the Plot Properties Tabs This section describes how to configure, and customize plots. There are seven property tabs containing many different configuration options. You may also customize a line or curve on the plot by moving the cursor over the line, and clicking the right mouse button. You can access the Plot Properties tabs four ways: z

Click the right mouse button on the plot (but not over a line) a list of the associated plots, maximize/minimize options, graph/grid and an option to access plot properties will appear for your selection.

z

Double-click on any plot.

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Use Edit > Properties when a plot is active.

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Click on the plot and then selecting the Properties button on the Plot toolbar.

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Changing the Scale Use the Plot Properties > Scale tab to define axis limits. Click Auto to allow the axis range to be calculated based on the limits of the data being displayed. This is the default.

Click Fixed Scale to specify a fixed number of units per inch (or cm) on the printed page for the X and Y axis. Click Fixed Range to specify range limits.

Click Use the same scale for both axes to choose the largest of the two specified (X and Y) scales, and use this scale for both axis.

Configuring the Axis Use the Plot Properties > Axis tab to define how and where the axis will be displayed.

Click Draw axis at the edges of the graph to keep the axis lines at the edges of the graph.

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Changing the Grid Use the Plot Properties > General/Grid tab to define the grid, tick marks, and graph border. Mark Show Grid to display a grid on the plot.

Specify the number of minor tick marks.

Specify the spacing of the major tick marks when printing the plot.

Mark Border around the graph to include a thin black line around the outside of the plot area.

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Changing the Axis Labels Use the Plot Properties > Labels tab to specify axis labels (text).

Type labels for the X and Y axes in their respective fields.

Changing the Font Use the Font tab to specify fonts for axis labels, and tick labels. Click Axis Label to specify axis label font. Click Tick Label to specify tick font. Click Data Labels to specify data label font.

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Changing the Line Styles Use the Plot Properties > Line Styles tab to specify color, style and width of lines used for the axis and the grid.

You can specify one set of lines for displaying on the screen and another set for printing.

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Click... to display available colors.

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Using Data Markers Use the Plot Properties > Markers tab to specify the use, size and frequency of data point markers.

Mark Show Data Markers to turn on data markers or symbols. The default setting is unchecked (no data symbols).

Click Every to specify the frequency of the data markers. You must specify a numeric value to indicate the frequency to place data markers.

Mark Always one at the end to assure the last point on the curve always has a marker even if the frequency specified means the point would not have a marker.

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Configuring the Legend Use the Legend tab to specify whether a legend should be displayed, and to customize legends, including title, font, and location.

Mark Show Legend to display a legend. Specify the number of columns the legend box should use. This is only relevant if several curves are represented in the legend.

Specify the title displayed in the legend.

Click Font to customize the font used for the legend.

Mark Show all lines to specify that all lines should be shown.

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Changing the Plot Background Color Use the Plot Properties > Background tab to specify the background color or a bitmap for plots. This tab is only available when a plot is the currently active view. Check this box if you want the background color or bitmap applied only to the grid area of the plot.

Click Color to select a color for the background.

Click Bitmap to use a bitmap as the background. You must specify the location of the bitmap.

Mark Center to display the bitmap in the center of the plot. Mark Stretch to Fit to stretch the bitmap to fill the plot.

Mark Maintain Aspect Ratio if you want to stretch the bitmap to fit the grid or graph but maintain the same dimension ratio.

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Using Libraries What is a Library? A Library (Libraries) is a WELLPLAN tool. You can use this tool to store work strings or fluids for future use. Once a work string or fluid is stored in a library, you can retrieve (import) it quickly and easily to create a new fluid or work string based on the retrieved string or fluid. For example, you can use a workstring library to store commonly used assemblies. Once a workstring is imported from a library, you can edit it to meet your current objectives. A library should not be confused with a catalog. A catalog contains a collection of similar workstring components that can be used to build a workstring. For example, there are jar catalogs, or drill pipe catalogs. A library is used to store the complete workstring, not a certain type of workstring component. You can use the fluid library to store commonly used fluids. Each fluid entry in the library includes all the data required to define that fluid, such as rheological model, weight, gel strength, etc. As with workstring library entries, once you have imported a fluid from a library into the case you are working with, you can edit the data as desired.

Using String Libraries Creating or Deleting a String Library Entry 1. Using the Case > String Editor, input the string. 2. Click the Export button to export the string to the library. This will not remove the string from the String Editor. A copy of the string is added to the string library.

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3. Specify the Assembly Name in the dialog that appears and click Export.

Click the Delete button to delete the highlighted string library entry.

Retrieving a String From the String Library 1. Using the Case > String Editor, click the Import button to export the string to the library. 2. A message will appear indicating that any current string data will be overwritten. Click Yes to continue.

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3. Highlight the string that you want to use from the list of string library entries.

4. Click Import and the String Editor will be filled with data from the library entry you selected.

Using Fluid Libraries Importing, Exporting, Deleting, and Renaming a Fluid Library Entry 1. Using the Case > Fluid Editor, input the fluid. 2. Click the Library button. 3. Using the Import/Export Fluids dialog, select the wellbore fluids you want to move to the library, or select the library fluid(s) you

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want to move to the wellbore fluids. Use the arrows to move the fluids after you have selected them.

Click the Delete key to delete the highlighted fluids from either the library or the wellbore fluid list. Click the Rename key to rename the highlighted fluids from either the library or the wellbore fluid list.

Exporting a Library Libraries can be shared with other users by exporting them at the database level. 1. Right-click on the database icon in the Well Explorer. 2. Select Export from the menu. 3. Specify the file name of the library export file. 4. Click Save. The file will be saved with the extension .lib.xml.

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Using Workspaces What is a Workspace A workspace is a template for how you want tabs, panes, arrangement of plots within panes, etc. to appear in WELLPLAN. No default data is stored in workspace. There are three types of workspaces: z

System Workspace - System Workspaces are read-only, and are shipped with the EDM database. You may apply them, but not alter them. There is a separate System Workspace for each module.

z

Module Workspace - Module Workspaces will apply automatically when you activate a given module (Hydraulics, Surge, etc.). To save a workspace as a Module Workspace, select File > Workspace > Save As Default. It will automatically apply the module tool tip name as the default module workspace name. You may import new module workspaces or delete them, but you cannot edit the name of any module workspace. Module workspaces are stored on a per-user basis. There is one module workspace per module. To delete a module workspace, right-click on it in the Well Explorer and select Delete from the right-click menu.

z

User Workspace - You can save any workspace as a User Workspace, so long as it has a unique name. Workspaces always have a .ws.xml extension. To save a workspace as a user workspace, select File > Workspace > Save, or right-click on the workspace in the tree and select New. Provide a name and click OK. You can import and export user workspaces. Importing user workspaces is an add/replace function; that is, if the name already exists on the target, the imported workspace will overwrite it. When exporting, you must give the workspace a .ws.xml extension.

Applying a Workspace Any of the three workspaces can be applied to the currently opened case. Workspaces can only be applied to open cases. To apply a workspace, select File > Workspace > Apply. You can also apply a workspace by double-clicking on the workspace in the Well Explorer.

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Configuring a User Workspace A user workspace is configured by creating and populating tabs using windows and window panes. This section discusses this process.

Using a Window Each open case occupies one window, and each window belongs to one case. A window can contain one or more screen layers, which are selected using the tabs along the bottom edge of the window. Each layer contains one or more window panes, and each pane can contain different contents. In addition, each pane may contain scroll bars, which become active when the contents are too large to fit inside the frame. The frame governs the amount and location of the screen space taken up by each window. It is the thin gray border around each pane and around the window. Windows exist in one of three states: • • •

Maximized - the window takes up all of the available space within the application frame Minimized - an icon within the application frame Restored - original size and position

If a window is in its restored state, it will have a Title Bar. The Title Bar is the thick colored band along the top of the window. The center of the title bar contains the name of the active spreadsheet, table, plot, or schematic, and the name of the case to which the window belongs. The left edge of the title bar contains the Window Control Menu, and the right edge contains three buttons. The first is the Minimize button, the second is the Maximize button, and the third is the close button. At any given time there is one and only one active window, and it belongs to the active case. A colored title bar denotes the active window; all others are gray.

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Window Title Bar

Tabs

Window panes (2)

Window splitter

Scroll bar

Scroll bar

Using Window Panes Each window contains one or more layers, and each layer can contain different information. A pane frames information, such as a well schematic, spreadsheet, table or plot. Light gray dividers denote panes. By default, each layer contains only one pane, but you can split this into up to four panes using the window splitters located at the ends of the scroll bars. To vertically split the screen, the splitter is in the lower left corner of the windowpane. To horizontally split the screen, the splitter is in the upper right corner of the windowpane

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Using Tabs Each window contains one or more layers (tabs), and each layer can contain different information. Only one layer is visible at any given time. To switch between layers, use the mouse to select the associated tab. Tabs are arranged along the lower left edge of the window, a region that they share with the window's horizontal scroll bars. You can control the amount of space allocated to each using a splitter. As you drag this splitter left and right, the amount of room available in which to display tabs grows and shrinks. If there is not enough room to display all of the tabs, you can scroll through them using the tab scroll buttons. Note that you can add, delete, rename and re-order tabs using the View > Tabs dialog. You can also double-click the tab, and the Rename Tab dialog opens.

Adding and Naming Tabs Use View > Tabs to add, delete, rename, and rearrange window tabs. .

Use the arrow buttons to move the highlighted tab to another position in the tab list.

To Add a Tab 1. Use View > Tabs to access the Tab Manager dialog. 2. Click New. The new tab appears at the bottom of the list and is highlighted. It also appears as the right-most tab at the bottom of the well file window. 3. Repeat steps 1 and 2 for each tab you want created. 4. When finished, click OK.

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Renaming a Tab 1. Use View > Tabs to access the Tab Manager dialog. 2. Double-click the tab you want renamed. The Rename Tab dialog appears. 3. Type the new name in the Tab Name field. 4. Click OK. The Rename Tab dialog closes.

Repositioning a Tab 1. Use View > Tabs to access the Tab Manager dialog. 2. Highlight the tab name in the list to be repositioned. 3. Do one of the following:

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Click to move the tab to the top of the list. The tab will be placed in the left-most position of the active window.

•

Click to move the tab up one level in the list. Each level up places the tab one position to the left in the active window.

•

Click to move the tab down one level in the list. Each level down places the tab one position to the right in the active window.

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Click to move the tab to the bottom of the list. The tab will be placed in the right-most position of the active window.

4. Repeat steps 2 and 3 for each tab you want repositioned. 5. When finished, click OK.

Saving the User Workspace Configuration After you have configured the workspace, you can save the configuration for future use with the File > Workspace > Save option.

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Using Data Status Tooltips and Status Messages Click View > Status Messages to toggle the functionality between active and inactive. If the option is active, a check mark will be visible beside the option. If this option is active, the last engineering analysis error (if any) will be displayed as a tooltip when the mouse is placed over a calculated field in a Quick Look section of a dialog. If the dialog doesn’t have a Quick Look section, this option does not apply. When View > Status Messages is active, a message window at the bottom of the active window indicating any error messages generated from analysis results.

Status messages and Tool Tips indicate that Pump Pressure can not be zero.

Tool Tip

Status Message

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Configuring Tool Tips and Field Descriptions You can configure the tool tip and descriptions for many fields in WELLPLAN. This is a convenient feature that can be used to re-label fields in another language, or to change the description for other reasons. For example: 1. Access the Case > Geothermal Gradient dialog. 2. Place the cursor in the Surface Ambient field.

Notice the field name.

3. Press F7. 4. Using the Data Dictionary dialog that appears, change the Custom Description and Custom Label for this field.

Change the field description and label.

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5.

Notice the field label as changed on the Case > Geothermal Gradient dialog.

6.

Notice the tool tip for this field has also changed.

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Chapter 5

Describing the Case Using the Case Menu Overview In this section of the course, you will become familiar with entering data that describes the general characteristics of the Case. Data input using the Case menu will be used in all analysis modes of a particular analysis module. Therefore, the contents of the Case menu vary depending on the analysis module you are using. In this chapter, only the Case menu items that are used in more than one analysis module will be discussed. The Case menu options that are available in only one analysis module will be covered during the discussion of that particular module. The Case is defined or created using the Well Explorer. Please refer to “Working at the Case Level (WELLPLAN Only)” on page 102 for more information on creating a Case. After a Case is created, use the Case menu to describing the Case. This chapter discusses the use of the Case menu to define some of the properties of the Case. In this section of the course, you will become familiar with: Defining the hole section Defining the workstring Managing wellpath data Defining and activating drilling fluids Specifying circulating system equipment Specifying pore pressure data Specifying fracture pressure data Specifying geothermal temperature data Defining string eccentricity

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Chapter 5: Describing the Case Using the Case Menu

Entering Case Data The Case menu (a selection on the menu bar) is used to enter data including hole sections, workstring, fluid, etc. The contents of the Case menu will change depending on the module you have selected because modules require different information about the well. Later, we will use the Parameter menu to enter additional data specific to the analysis type you are performing. It is recommended that you begin entering data in the first menu item available on the case menu and work your way down the menu selections. You can use the Wizard Toolbar to enter data in the proper order.

Defining the Hole Section Geometry The Case > Hole Section Editor is used to define the inner configuration of the well including the components of the hole section and the material properties of the components. Open hole sections are also defined using the Hole Section Editor. The well configuration can be entered entirely using the Hole Section Editor or can be copied from another Case using the Well Explorer. Refer to “Working With Designand Case-Associated Components” on page 108 for more information about copying associated items. The Hole Section is associated to a particular Case. Refer to “Associated Data Components” on page 57 for more information concerning the Well Explorer and linked data items. Since a Design (as defined in the Well Explorer, “Working at the Design Level” on page 98) can have multiple Cases, you need to enter data into the Hole Section Editor to define the well profile and well depth of a particular Case for analysis. The hole section configuration is common for all WELLPLAN modules while analyzing the Case the hole section is associated to. You must enter the hole section information from the surface down to the bottom of the well. When you make a selection from a Section Type cell (other then Open Hole), a dialog specific to that section type appears. You must fill in the data in the dialog in order for that section type to be recorded in that cell. You also must fill in all editable cells in the spreadsheet row.

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Each row defines a section of the hole. For cased sections, specify the effective hole diameter of the hole into which the casing is inserted. (Do NOT enter the casing OD.) This diameter is used for surge calculations to compute elastic properties. For open hole sections, the effective hole diameter is used to represent the actual size of the hole.

Volume Excess % is calculated based on effective hole diameter.

Note: Using the effective hole diameter... For cased sections, specify the effective hole diameter of the hole into which the casing is inserted. (Do NOT enter the casing OD.) This diameter is used for surge calculations to compute the elastic properties. For open hole sections, the effective hole diameter is used to represent the actual size of the hole. Volume Excess % is calculated based on effective hole diameter. If you import a caliper log into WELLPLAN, you should double-check the values for any rows labeled Open Hole. The Import Caliper Log function takes the number of blocks specified by the user and creates the same number of rows in the spreadsheet, averaging the individual measured hole diameters into each section described in the spreadsheet. Logs that start at the bottom of the casing may not continue all the way to the top of the well, in which case the first geometry may need to be added to the top of the outer geometry table after performing the import. Washed out portions of a well may cause the caliper to record values such as -999.0, which represents an unknown value. If any value is blank, you must enter an appropriate diameter by typing it into the spreadsheet.

Hole Section Editor Menu When the Hole Section Editor is visible, the menu bar has an additional menu option available. This menu option titled Hole Section is used to access the catalog.

Defining a Work String The Case > String Editor is used to define all types of tubular work strings and their components. Casing, liner, tubing, coiled tubing, and

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drill strings are all defined using this spreadsheet. Strings can be entered from the top down or from the bottom up. You must specify the length of the section and several other defining properties of the section that will be used in further analysis. String depth is an important item on this form, and indicates the bit depth used in many of the analysis modes. When you make a selection from a Section Type cell, a dialog specific to that section type appears. You must fill in the data in the dialog in order for that section type to be recorded in that cell. You also must fill in all editable cells in the spreadsheet row. Workstrings can be entered entirely, or can be copied from another Case using the Well Explorer. Refer to “Associated Data Components” on page 57 for more information. Since a Design (as defined in the Well Explorer, “Working at the Design Level” on page 98) can have multiple Cases, you need to enter data in this editor to define the workstring of a particular Case. The workstring configuration is used for all WELLPLAN modules while analyzing the Case the workstring is associated to.

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Select string entry order. Select from Top-to-Bottom, or Bottom-To-Top. Click on a component, then use String > Click the Export button to export a string Catalog to access the catalog for a to the library. Click the Import button to component or use String > Data to edit import the string from the library. The the data for a component. String Name field on this spreadsheet is the unique identifier for the string when Enter string depth. It will importing or exporting from/to a library. be used in many analysis Refer to “Using Libraries” on page 148. modes.

To edit or view information concerning a particular component, click any data cell pertaining to the component and then use String > Data.

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Use Tools > Tubular Properties to edit the tubular material types, material properties, grades, or classes available for selection on the drop-down list.

You can change much of the information describing the component on the Data dialog, however these changes are not made to the catalog entry corresponding to the component. You must use the Well Explorer to change the catalog entry. Refer to “Working With Catalogs” on page 110 for more information. On the component data dialog there are some material property cells that can not be edited. This information is related to the grade, class and material selected for the component from the drop-down lists. Use Tools > Tubular Properties to add or edit component material types, grades, or class.

Managing Wellpath Data The Case > Wellpath menu item has a submenu. Use these menu choices to enter wellpath data, apply tortuosity to the wellpaths, and define survey calculation methods.

Importing Wellpath Files You can import survey data points using File > Import > Wellpath File. This is useful if you have wellpath data from a source other than another Landmark software product. A wellpath file must meet the following requirements to be imported using this option. •

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The data must be in ASCII format or reside in the Windows Clipboard.

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•

• •

The data must be in columns, each separated by a comma, tab, or blank space. If you are using the Clipboard to import from Excel, use “Tab” as the column delimiter. Each row must have the same format. The measured depth, inclination and azimuth must be in a supported unit.

Specify data units. Specify data order.

Import from a file or from the Clipboard.

Entering Wellpath Data Use Case > Wellpath > Editor to enter wellpath data points. You must specify measured depth, inclination, and azimuth. The rest of the information displayed in the non-editable cells will be calculated for you. Wellpath data is calculated using the minimum curvature method. The checkbox is disabled for non-actual designs. For actual designs, you can click on the box and WELLPLAN generates a definitive survey path from actual surveys (i.e. enter surveys in OpenWells and use this to generate from this entered data). After selecting the box, the definitive survey becomes locked (since it is calculated). If the box is not checked, the definitive survey editor returns to its previous state.

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Setting Wellpath Options Use Case > Wellpath > Options to add tortuosity to a wellpath, or to interpolate between data points. You can add tortuosity to wellpath data points. Tortuosity is designed to apply a “rippling” to a planned wellpath to simulate the variations found in actual surveys. Tortuosity should never be applied to actual survey data. The three tortuosity methods available are sine wave, random inclination dependent azimuth, and random inclination and azimuth. The sine wave modifies the inclination and azimuth of the survey based on the concept of a sine wave shaped ripple running along the wellbore. The random methods apply random variation to the inclination and azimuth. This method is based on SPE 19550. Refer to the online help or to “Tortuosity” on page 244 for more information.

Magnitude is the maximum variation of angle that will be applied to the inclination and azimuth of the native (untortured) wellpath.

Select one tortuosity method. For the Sine Wave method this is the wavelength of the ripple. For the Random methods, the Angle Change Period is used to normalize the measured depth distance between wellpath points.

Wellpath data is calculated at the interval specified.

Viewing Wellpaths w/Tortuosity Case > Wellpath > View w/Tortuosity data is only available if tortuosity has been applied using the Case > Wellpath > Options dialog. This spreadsheet displays a read-only view of the wellpath that had tortuosity applied.

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Most cells in this spreadsheet are read-only.

Viewing Wellpath w/Interpolation The survey data displayed using Case > Wellpath > View w/Interpolation is a read-only view of the interpolated survey data set. If interpolation is not applied in the Case > Wellpath > Options dialog, a default interval of 30 ft will be used. Interpolated survey data is added to the surveys specified in the Case > Wellpath > Editor.

Most cells in this spreadsheet are read-only.

Defining the Active Fluid and Fluid Properties Defining Drilling Fluids Use Case > Fluid Editor to define drilling fluids, including muds, cements, spacers, etc. All fluids analyzed using WELLPLAN must be defined using this editor. Most analysis modules will use the fluid marked as active on this editor. Surge and Cementing have the option of

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using more than one fluid in the analysis by specifying the fluids used on the Parameter > Job Data dialog. However, the fluids must be defined using Case > Fluid Editor before the fluid can be selected using the Parameter > Job Data dialog. Refer to “Defining the Wellbore Fluids and Specifying Pump Rates” on page 415 for the use of the Parameter > Job Data dialog in Surge. Refer to “Defining the Cement Job Fluids” on page 460 for the use of the Parameter > Job Data dialog in Cementing. Four rheology models are available, including: Power Law, Bingham Plastic, Newtonian, and Herschel Bulkley. For each model you can choose to enter PV/YP data or Fann data. For more information on rheology models, refer to “Power Law Model” on page 332, “Bingham Plastic Model” on page 331, or “Herschel Bulkley Model” on page 332.

Click Activate to activate the selected fluid. Data for the selected fluid is displayed in the dialog.

Check the Cement box to define a cement.

Click Library to access the fluid library. Refer to “Using Libraries” on page 148 for more information.

Refer to the online help for detailed field descriptions.

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Specify Circulating System Equipment Use the two tabs on the Case > Circulating System dialog to specify surface equipment and mud pumps data. On the Surface Equipment tab, you may choose one of four pre-defined surface equipment configurations.

Enter the rated maximum working pressure.

To enter the expected pressure loss through the surface equipment, click Specify Pressure Loss. To calculate it, click Calculate Pressure Loss.

To calculate the pressure loss, you must select/specify the surface equipment configuration.

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Select the category of surface equipment that you want to use from the dropdown list. You don’t need to select or specify a surface equipment configuration if you specify the pressure loss.

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Use the Case > Circulating System > Mud Pumps tab to enter information pertaining to all pumps available. You may indicate which pump(s) are currently active by clicking the Active check box.

Rather than input all the data for the mud pump, you can select a pump from the catalog. Click Add from Catalog to select a pump from the catalog.

Check this box to specify active pump. Insert a new row by entering data in the next empty row, or by highlighting a row and pressing the Insert key on your keyboard. Delete a row by highlighting it and pressing the Delete key on your keyboard.

Specifying Circulating System for Cementing Analysis When using the OptiCem Analysis module, the circulating system dialog is different than the dialog used for the other analysis modules. When using OptiCem, use the Case > Circulating System dialog to specify whether you want to include surface iron in the analysis, and if

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so, to specify information about the surface iron. This dialog is also used to specify the pump volume per stroke.

Specifying Pore Pressure Data Use the Case > Pore Pressure spreadsheet to define the pore pressure profile as a function of vertical depth. You may enter either pressure or EMW (ppg) for a vertical depth and the other value will be calculated based on vertical depth. You may enter several rows of data to define many pore pressure gradients. The depths specified on this spreadsheet are automatically used as depths of interest on the plots. Note: Defining Pore Pressure... Although pore pressure are defined using the Case menu, pore pressures are linked to the Design level. Therefore, any changes to the pore pressure for one Case will affect all Cases linked to the same Design. Refer to “Working With Design- and Case-Associated Components” on page 108 for more information.

You can copy/paste pore pressure data from an Excel spreadsheet or from another case within WELLPLAN. Enter Pore Pressure and EMW is calculated. or Enter EMW and Pore Pressure is calculated.

Specifying Fracture Gradient Data Use the Case > Frac Gradient spreadsheet to define the fracture pressure profile as a function of vertical depth. You may enter either Landmark

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pressure or EMW (ppg) for a vertical depth and the other value will be calculated based on vertical depth. You may enter several rows of data to define many fracture gradients.The depths specified on this spreadsheet are automatically used as depths of interest on the plots. Note: Defining Fracture Gradients... Although fracture gradients are defined using the Case menu, fracture gradients are linked to the Design level. Therefore, any changes to the fracture gradient for one Case will affect all Cases linked to the same Design. Refer to “Working With Design- and Case-Associated Components” on page 108 for more information.

You can copy/paste pore fracture gradient data from an Excel spreadsheet or from another case within WELLPLAN.

Enter Frac Pressure and EMW is calculated. or Enter EMW and Frac Pressure is calculated.

Specifying Geothermal Gradient Data Use the Case > Geothermal Gradient tabs to define the geothermal temperature profile as a function of depth. The Standard tab is used to specify basic formation temperature data. The well temperature at total depth can be specified, or it can be calculated from a gradient.

Click here to specify temperature at TD. Click here to specify a gradient to use to calculate temperature.

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The Additional tab can be used to add temperatures to characterize a non-linear formation or seawater profile. These temperatures must be entered on a true vertical depth basis. Intermediate temperatures are linearly interpolated between specified points.

Enter temperatures based on TVD.

Defining String Eccentricity Use the Case > Eccentricity spreadsheet to specify the eccentricity ratio of the annuli at different depths. Eccentricity reduces the pressure drop for annular flow. The Hydraulics module will automatically calculate eccentricity using the tool joint diameter regardless of what is entered in the eccentricity spreadsheet. If you specify eccentricity in the spreadsheet, and the calculated tool joint eccentricity is less than the specified eccentricity, the calculated tool joint eccentricity will be used for the engineering calculations. If you check the Concentric Annulus box, the string will be centered in the wellbore regardless of the wellbore deviation or the calculated tool joint eccentricity. An eccentric annulus ratio is defined by specifying the displacement from the centerline divided by the radial clearance outside the moving pipe. First define the eccentricity for each annular section and then its eccentric value. Define the annular section by specifying a depth in the Depth cell for the row, and then specify an eccentric value for the section. A value of zero is concentric and a value of 1 is fully eccentric. You can use the WELLPLAN Torque Drag module Position Plot to determine the position of the string in the wellbore. The position in the wellbore can be used to determine the eccentricity. Remember, you must use a stiff string analysis to generate a Position plot. Landmark

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Check the Concentric Annulus box to indicate the entire string is concentric in the annulus. If this box is checked, data in the spreadsheet will not be used.

Enter eccentricity = 1 to indicate string positioned against the wellbore

Note: Defining Eccentricity... The Eccentricity spreadsheet is only available when you are using the Herschel Bulkley rheology model. Select the rheology model on the Case > Fluid Editor > Standard Muds tab. If you are using the Herschel Bulkley rheology model, and the Eccentricity spreadsheet is still not available, try opening the Hole Section Editor and then reopening the Eccentricity spreadsheet.

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Chapter 6

Torque Drag Analysis Overview Torque Drag Analysis predicts and analyzes the torque and axial forces generated by drill strings, casing strings, or liners while running in, pulling out, sliding, backreaming and/or rotating in a three-dimensional wellbore. The effects of mud properties, wellbore deviation, WOB and other operational parameters can be studied. At the end of this chapter you will find the methodology used for each analysis mode. The methodology is useful for understanding data requirements, analysis results, as well as the theory used as the basis for the analysis. Supporting calculations and references for additional reading are also included in this chapter. In this section of the course, you will become familiar with all aspects of using the Torque Drag Analysis module, including: Available analysis modes Defining operating parameters Calibrating coefficients of friction using field data Using drag charts to predict the maximum measured weight and torque expected for a depth range Analyzing critical measured depths where torque and drag may be a problem

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Chapter 6: Torque Drag Analysis

Workflow The following is a suggested workflow. Many other workflows can be used. Open a Case using the Well Explorer. Refer to “Using the Well Explorer” on page 55 for instructions on using the Well Explorer. Define the hole section geometry and friction factors. (Case > Hole Section Editor) Use advanced friction factors (click Advanced button on Parameters > Run Parameters dialog) to specify different friction factors for different operations in cased and open hole. Define the workstring. Use the same dialog to define all workstrings (drillstrings, tubing, liners, and so forth) (Case > String Editor) Enter deviation (wellpath) data. (Case > Wellpath > Editor) Define the fluid used. (Case > Fluid Editor) Specify calculation methods, weight indicator corrections, and mechanical limitations to analyze. (Case > Torque Drag Setup Data) Optional: Specify fluid columns if more than one fluid is present in the string, the fluid system is circulating, there is surface pressure applied to the string, or different fluid densities exist in the annulus and string. (Parameter > Fluid Columns) Optional: Record actual load data recorded while drilling. This information is useful for calibrating coefficients of friction or for comparing to predicted data. (Parameter > Actual Loads) Optional: Specify standoff device parameters. (Parameter > Standoff Devices) Optional: Calibrate coefficients of friction if actual load data is available. Calibrating coefficients of friction is recommended if actual load data is available.

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1.) Access the Calibrate Friction analysis mode. (Select Calibrate Friction from the Mode drop-down list.) 2.) Specify actual load information and view calculated coefficients of friction. (Parameter > Calibration Data) Determine the maximum measured weight and torque expected over a depth range. 1.) Access the Drag Chart analysis mode. (Select Drag Chart from the Mode drop-down list.) 2.) Specify the analysis parameters. (Parameter > Run Parameters) 3.) Evaluate measured weights to determine if string tensile limit is exceeded. (View > Plot > Tension Point Chart) 4.) Evaluate string torque to determine if make-up torque is exceeded. (View > Plot > Torque Point Chart) 5.) Use the View > Plot > Sensitivity Plot Tension plot to quickly view the measured weights using various friction factors. If you have actual data, you can use this plot to determine which friction factor best matches the actual data. Use advanced friction factors (click Advanced button on Parameters > Run Parameters dialog) to specify different friction factors for different operations in cased and open hole. Analyze in detail the depths that encounter high measured weights or torques. 1.) Access the Normal Analysis or Top Down Analysis mode. (Select Normal Analysis from the Mode drop-down list. If this is a coiled tubing operation, select Top Down Analysis from the drop-down list instead.) 2.) Specify the operating modes and parameters to analyze. (Parameter > Mode Data) 3.) Determine if buckling, fatigue, exceeding of torque limit, exceeding 100% of yield, or exceeding the yield strength safety factor occurs. (View > Table > Summary Loads) 4.) Investigate the loads occurring at specific depths during an operation. (View > Table > Load Data > Tripping In, Tripping

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Out, Rotating On Bottom, Rotating Off Bottom, Sliding or Backreaming) 5.) Investigate the stresses occurring at specific depths during an operation. (View > Table > Stress Data > Tripping In, Tripping Out, Rotating On Bottom, Rotating Off Bottom, Sliding or Backreaming) 6.) Determine if the forces in the string are near the tensile limit or if the string is buckling. (View > Plot > Effective Tension) 7.) Determine if the string torque is near the make-up torque limit. (View > Plot > Torque Graph)

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Introducing Torque Drag Analysis The Torque Drag Analysis module predicts the measured weights and torques while tripping in, tripping out, rotating on bottom, rotating off bottom, slide drilling, and backreaming. This information can be used to determine if the well can be drilled or to evaluate hole conditions while drilling a well. The module can be used for analyzing drillstrings, casing strings, liners, tieback strings, tubing strings, and coiled tubing. The Torque Drag Analysis module includes both soft string and stiff string models. The soft string model is based on Dawson’s cable model. In this model, the work string is treated as an extendible cable with zero bending stiffness. Friction is assumed to act in the direction opposing motion. The forces required to buckle the string are determined, and if buckling occurs, the mode of buckling (sinusoidal, transitional, helical, or lockup) is indicated. The stiff string model includes the increased side forces from stiff tubulars in curved hole, as well as the reduced side forces from pipe wall clearance. For more information, refer to “Supporting Information and Calculations” on page 217 or “References” on page 250.

Starting Torque Drag Analysis There are two ways to begin the Torque Drag module: z

Select Torque Drag from the Modules menu, and then select the appropriate analysis mode.

z

Click the Torque Drag button and then select the appropriate analysis mode from the drop-down list.

The contents of the Case and Parameter menus vary depending on the analysis mode you select.

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Choose Torque Drag Analysis from the Module menu or by clicking the Torque Drag Module button.

Select desired Torque Drag Analysis mode from submenu or from Mode drop-down list.

Available Analysis Modes The Torque Drag Module has four available analysis modes. The analysis modes are described in the following text.

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Normal Analysis: Use the Normal Analysis mode to calculate the forces, torques, and stresses acting on the work string while the bit is at a particular depth in the wellbore for a number of common drilling load conditions. This analysis calculates surface loads based on bit forces you specify. Refer to “Normal Analysis” on page 209 for more information.

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Calibrate Friction: Use the Calibrate Friction analysis mode to calculate the coefficient of friction for cased and open hole sections using actual load data acquired while drilling. The calculated coefficient of friction can be used the torque and drag analysis. If you have access to actual load data, it is recommended that you calibrate the coefficients of friction and

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use the calibrated coefficients in your analysis. Refer to “Calibrate Friction Analysis” on page 211 for more information.

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Drag Chart: Use the Drag Chart analysis mode to plot the surface torque and measured weight from drilling operations while the bit traverses a range of depths in the wellbore. Refer to “Drag Chart Analysis” on page 212 for more information.

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Top-Down Analysis: Use Top-Down Analysis to calculate the string forces based on loads and torque applied at the surface or at the bottom of the string. (When loads are applied at the bottom of the work string, this analysis is very similar to the Normal Analysis but there is more flexibility over movement and end conditions.) If the surface loads are input, the bit forces are calculated and vice versa. You can specify if the string is rotating, and reciprocating during tripping operations. Refer to “Top Down Analysis” on page 214 for more information.

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Defining the Case Data Refer to “Entering Case Data” on page 162 for instructions on entering data into the Case menu options.

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Defining Operating Parameters Specifying Weight Indicator Corrections, Analytical Models and Reporting of Mechanical Limitations Use Case > Torque Drag Setup to specify weight indicator corrections, analytical models and to select reporting of mechanical limitations.

Check this box to include sheave friction in all measured weight calculations. If you want to enable this model, you must also specify the Lines Strung and the Mechanical Efficiency values.

Check box to use Bending Stress Magnification corrections. The Stiff String model computes the additional side force from stiff tubulars bending in a curved hole as well as the reduced side forces from pipe straightening due to pipe/hole clearance. Check box to select the viscous fluid torque and drag model. The viscous fluid effects cause differing torque and drag on the string depending on the pipe rotation and trip speeds. The magnitude depends strongly on the fluid rheology model chosen in the fluid editor. Specify the length that you want the contact forces reported for. Check boxes for limitations you are interested in.

Enabling Sheave Friction Corrections When the Enable Sheave Friction Correction model, it is applied to all measured weight calculations. You must specify the lines strung and the mechanical efficiency. Friction estimates from pick-up and slack-off

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loads are underestimates because uneven distribution of dynamic loads to drilling lines are caused by friction in the block sheaves. Martin-Decker–type deadline weight indicators do not account for this problem. Actual pick-up loads are therefore always greater than indicated while slack-off loads are always less than indicated. When you use pick-up or slack-off hook load measurements as the basis for friction factor determinations, this error source results in pick-up friction factors that are too low and slack-off friction factors that are too high. Errors in hook-load determination can be of the order of 20 percent due to this error source (depending on lines strung), and the effect on friction factor determinations can therefore be significant and worth correcting. Refer to “Sheave Friction” on page 234 for more information.

Why Use Bending Stress Magnification Factor? In both tensile and compressive axial load cases, the average curvature between the tool joints is not changed, but the local changes of curvature due to straightening effects of tension or the buckling effects of compression may be many times the average value. Therefore to accurately calculate the bending stress in the pipe body requires the determination of these local maximum curvatures. The quantity bending stress magnification factor (BSMF) is defined as the ratio of the maximum of the absolute value of the curvature in the pipe body divided by the curvature of the hole axis. This factor can be applied as a multiplier on the bending stress calculations to more accurately calculate the bending stress in a work string that has tool joints with outside diameters (OD) greater than the pipe body. This modified bending stress is then used in the calculation of the von Mises stress of the pipe. BSMF is useful because when a drill string with tool joint OD greater than the body OD is subjected to either a tensile or compressive axial load, the maximum curvature of the drillpipe will exceed that of the hole axis curvature. The drillpipe sections conform to the wellbore curvature primarily through contact at the tool joints. BSMF is applied to the calculated bending stresses when you mark the Use Bending Stress Magnification check box on the Case > Torque Drag Setup dialog. Refer to “Bending Stress Magnification Factor” on page 250 for more information.

Why Use the Stiff String Model? On the Case > Torque Drag Setup Data dialog, check the Use Stiff String Model to use the stiff string model in the calculations. The stiff

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string model computes the additional side force from stiff tubulars bending in a curved hole as well as the reduced side forces from pipe straightening due to pipe/hole clearance. This model is complex, and therefore takes a significantly longer time to run than the Soft String model. The Normal Analysis Position Graph plots and the Single Position plot are only available with the Stiff String model because the soft string model assumes that the pipe is always positioned at the center of the hole. For more information, refer to “Stiff String Model” on page 237.

Including Viscous Drag Calculations On the Case > Torque Drag Setup Data dialog, check the Use Viscous Torque and Drag to include viscous fluid effects in the calculations. The viscous fluid effects cause differing torque and drag on the string depending on the pipe rotation and trip speeds. The magnitude depends strongly on the fluid rheology model chosen in the fluid editor. Refer to “Viscous Drag” on page 247 for more information.

Specifying Multiple Fluids or Surface Pressure The Parameter > Fluid Columns tabs are used to define the density of the fluids in the annulus and the string. Data entered on these tabs overrides data entered on the Case > Fluid Editor. You can also define a surface pressure to apply to the annulus. If you are not applying pressure at the surface, and you are using one fluid in the string and annulus, enter the fluid information on the Case > Fluid Editor. Use the Fluid Columns tabs if:

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There is more than one fluid in the annulus

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There is surface pressure applied to the annulus

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The fluid density in the annulus and string are different

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Tabs for entry of fluid columns in string and annulus.

Define a surface pressure to be applied to the annulus. Define a flow rate. This flow rate will be applied to all analysis modes.

Use this tab is used to define the density of the fluids in the annulus. You can also define a surface pressure to be applied to the annulus. If you do not enter data here, the mud weight entered in the Fluid Editor dialog becomes the default entry.

How does Fluid Flow Change the Forces and Stresses on the Workstring? Fluid flow changes the forces and stresses on the work string in three ways.

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The calculated Pump Off Force is an additional compressive force at the end of the string caused by the acceleration of fluid through the bit jets. The calculations for bit impact force are used to determine this force.

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Forces and stresses in the drill string are caused by the differential between the pipe and annulus fluid pressures from the hydraulic system, including bit and MWD / motor pressures losses.

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Fluid shear forces act on the work string as a result of shear stresses caused by the frictional flow in the pipe and annulus.

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How Does Surface Pressure Change the Forces And Stresses On the Workstring? z

Surface pressure in the string acts as an additional axial force.

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Surface pressure in the annulus acts as an additional compressive force.

Using Standoff Devices Use the Parameter > Standoff Devices dialog to describe standoff devices. You must check the Use Standoff Devices box to use these devices in the analysis. If the box is not checked, the devices will not be used. WELLPLAN can model both rotating and non-rotating devices. The model assumes that accurate placement of the devices has been determined so that the drillstring does not contact the wellbore in the interval where the devices are used. Each row of the table refers to a single type of device placed on consecutive sections of pipe. If more than one type of device is used, define each type on a separate row in the table. Note: Wellbore to string friction in sections where standoff devices are used is relative... For example, assume the wellbore friction (input using Case > Hole Section Editor) is 0.2. If the standoff device friction is 0.5, then the friction factor used in the calculations would be 0.2 X 0.5 = 0.1. This approach allows for accurate friction determination when using drag charts and moving the string between cased and open hole sections with different wellbore friction factors.

Note: Standoff Device Placement... The model assumes the devices have been placed so that the string does not contact the wellbore in the interval where the devices are used. The analysis does not determine device placement.

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Check box if you want to use standoff devices.

Use Frequency columns to specify the number of devices per joint. (A unit is a joint.)

Each row of the table refers to a single type of standoff device placed on consecutive sections of pipe. If more than one type of device is used, define each type on a separate row in the table. The unit weight is added to the string weight for analysis purposes.

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Calibrating Coefficients of Friction Using Field Data Coefficients of friction along the wellbore can be calculated from actual data collected while drilling. This provides a means of calibrating the model against actual field results. In order to use this analysis mode, you must collect a series of weights and torques at the wellsite. Some of this data is obtained with the string inside the casing shoe, and other information is obtained in the open hole section. When gathering actual field data, it is best if friction reduction devices are not being used. Over the sections where the devices are used, the effects of the friction devices must included in the calibrated friction factors. You must calculate the coefficient of friction in the cased hole section first, then the open hole. This is required because data recorded in the open hole section includes the combined effects of friction between the string and the casing as well as the friction between the string and the open hole. Therefore, the coefficient of friction for the cased hole must be determined before that of the open hole. The reliability of the data collected is important. Spurious values for any weight may prevent calculating a solution or may result in an inaccurate solution. It is important that the drillstring is completely inside the casing shoe when you are recording weights for calculating the coefficient of friction inside the casing. It is also important that the string is not reciprocated while recording rotating weights, and vice versa. You may not want to rely on one set of data, but make a decision based on a number of weight readings taken at different depths inside the casing and in the open hole section. It is important to realize that hole conditions may also effect the coefficient of friction calculated. If the actual weights recorded include the effects of a build up of cuttings, the BHA hanging up downhole, or other hole conditions. Because the recorded weights include these effects, the calculated coefficient of friction will also.

Starting the Calibrate Friction Analysis Mode

Select Calibrate Friction from Mode drop-down list.

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Recording Actual Load Data Use the Parameter > Actual Loads dialog to record actual load data encountered at certain depths. This information can be used to calculate coefficients of friction using the Calibrate Friction analysis or it can be displayed in the Drag Chart analysis graphs to compare actual values with calculated values. The actual load data consists of rows or information with one row per measured depth. You can record data for any measured depth. It may be useful to record this information just inside the casing shoe, or at total depth just prior to setting casing. It is not necessary to specify all values for each row. However, the measured depth must always be specified, and must always increase. The trip in and trip out measured weights, and rotating off bottom torque values are required to calibrate the coefficient of friction. Other values are input for plotting actual load data on applicable plots.

Required input for calibrating coefficient of friction

Calibrating Coefficients of Friction Use the Parameter > Calibration Data dialog to specify the parameters required to calibrate the coefficients of friction. You may calculate the coefficient of friction using the following two methods. The difference between the methods is that one method used an actual load input on the Parameter > Actual Loads dialog and the other method requires the input of the load directly onto the Parameter > Calibration Data dialog. z

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Be sure the use actual load check box is not checked and enter a bit MD. You must also enter at least one of the following: tripping out measured weight, tripping in measured weight, or rotating off bottom torque. The calculated coefficient of friction is based on the selected measured weights and/or torque values you entered for the specified bit MD.

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Chapter 6: Torque Drag Analysis z

Be sure the Use Actual Load check box is marked and select an actual load. You can select, deselect, or alter any of the measured weight or torque values recorded for this actual load. The calculated coefficient of friction is based on the selected measured weights and/or torque values.

The coefficient of friction can be calculated for the cased hole section, the open hole section, or be combined for both open and cased hole. When selecting from actual loads (entered on actual loads editor), be sure box is checked and select desired depth from drop-down list.

View the calculated average coefficient of friction used in analysis. The average coefficient of friction is calculated for the cased, open hole, or combined hole section selected.

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Predicting Maximum Measured Weight and Torque The Drag Chart Analysis predicts the measured weights and torques that will be experienced while operating the work string over a range of depths. The calculations performed for this analysis are similar to those used in the Normal Analysis except the calculations are performed over a range of depths. (A Normal Analysis calculates results for a single bit depth.) As in the Normal Analysis, you may select the operational modes by checking appropriate boxes on the Run Parameters dialog. Refer to “Drag Chart Analysis” on page 212 for more information. You can use coefficients of friction that you calculated using Calibrate Friction, the coefficients specified on the Hole Section Editor, or those entered on the Run Parameters dialog.

Starting Drag Chart Analysis

Select Drag Chart from drop-down list.

Defining Operating Conditions and the Analysis Depth Interval The Parameter > Run Parameters dialog is used to specify the analysis parameters for a Drag Chart Analysis. On this dialog you indicate the depth interval that you want to analyze. You also select the operational modes you want to analyze, and the forces acting at the bottom of the work string for each of the operational modes. You must also indicate the coefficient of friction that you want to use. Typically the depth range chosen would correspond to the expected run of a given string, or to a complete hole section if the drill string configuration was to remain unchanged throughout the hole section. Keep in mind that the drag chart analysis assumes that only one string,

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and only one set of operating parameters (fluid, WOB, and so forth) are used through the entire analysis depth range.

Be sure to enter interval to analyze. Use Torque/tension Point Distance From Bit to specify the depth along the drill string, expressed as the distance from the bit, for any point of interest in the string. The torque or tension at this point is displayed on the drag chart torque and tension plots. If you do not specify a depth, the torque or tension will be calculated at the surface. For example, if you are interested in the torque in a component that is 80 feet from the bit, enter 80 into this field. In this example, the torque generated in this component will be displayed in the graph.

Click Advanced to specify coefficients of friction associated with different operating modes.

Advanced Options Click the Advanced button to specify coefficients of friction associated with different operation modes. You must specify both cased and open hole friction factors for each operating mode. Only those operations specified on the Parameter > Mode Data dialog (Normal Analysis

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mode), the Parameter > Run Parameters dialog (Drag Chart Analysis mode) are accessible on the Advanced Options dialog.

Analyzing Drag Chart Results There are no reports available for a drag chart analysis. All output is in graphical form.

Tension Point Chart The View > Plot > Tension Point chart shows tension at the point in the string (as indicated by the Torque/Tension Point Distance from Bit specified on the Parameters > Run Parameters dialog) or the surface measured weight for all operating modes selected on the Parameter > Run Parameters dialog. This analysis covers only the measured depth interval specified on the Parameter > Run Parameters dialog. Use this plot to determine how much overpull you can place on the string before the string will fail. Similarly, you can determine how much compressive force can be applied to the string before the string will yield as a result of buckling. From the graph, you can determine the load that will fail the work string, but you will not be able to determine where the failure occurred.

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Buckling occurs in sliding and rotating on bottom operating modes at the corresponding bit depths.

Minimum measured weight to avoid buckling

Slackoff while tripping in at 3500 ft MD.

Overpull while tripping out when the bit is at 4,000 ft MD.

Torque Point Chart The View > Plot > Torque Point chart displays the maximum torque found at the surface or at a user specified point in the work string for all rotary operating modes selected on the Parameters > Run Parameters dialog. The Torque Point chart covers only the measured depth interval specified on the Run Parameters dialog. For reference, the makeup torque limit is displayed on the graph. The torque limit is derated for tension.

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Makeup torque as input on Case > Hole Section Editor for each component.

Using the Sensitivity Plot This plot displays the measured weights using different friction factors for the operations selected on the Run Parameters dialog. One operation is displayed on the plot at a time. The measured weights for all other operations selected in the Run Parameters Dialog can be viewed through the right-click mouse option. If the operation is not selected in the Run Parameters dialog, the respective right-click option will be disabled (greyed out). Only the measured depth interval specified on the Run Parameters dialog is covered. The plot displays the measured weights over the specified interval using the friction factors specified on the Case > Hole Section Editor. In addition, the measured weight is calculated using a friction factor that is twenty percent greater and twenty percent less than the cased hole

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friction factor specified on the Hole Section Editor while the open hole friction factor is varied between 0.1 and 0.4. Note: In order to display this plot... To display this plot, you must check the Enable Sensitivity Plot box on Parameter > Run Parameters dialog. If this box is not checked, the View > Plot > Sensitivity Plot Tension plot will not be available.

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Analyzing Critical Measured Depths Normal Analysis calculates the torque, drag, normal force, axial force, buckling force, neutral point, stress and other forces and stressed for a work string in a three-dimensional wellbore. With a Normal Analysis, all calculations are performed with the bit at one position in the wellbore (as indicated on Case > String Editor), and with one set of operational parameters. You may choose to perform the analysis using either the soft or stiff string model. Normal Analysis mode calculates the forces acting along the string and at the surface for several operating conditions, including: z

Tripping in (with and without rotating)

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Tripping out (with and without rotating)

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Rotating on bottom

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Rotating off bottom

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Backreaming

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Sliding drilling

Based on the API material specifications of pipe class, material, and grade, the following special load cases are also calculated. z

Maximum weight on bit to avoid sinusoidal buckling

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Maximum weight on bit to avoid helical buckling

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Maximum overpull to not exceed yield with the utilization factor while tripping out of hole

Start Normal Analysis Select Normal Analysis from dropdown list.

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Defining Operating Conditions Use the Parameter > Mode Data dialog to specify many of the analysis parameters required to perform a Normal Analysis. You may specify which operating mode you want to analyze by checking the appropriate box. The operating modes available include tripping in, tripping out, rotating on bottom, rotating off bottom, sliding, and backreaming. Depending on the operating modes selected, you will be required to specify operating parameters related to that operating mode. The operating parameters may include WOB or Overpull, torque at bit, tripping speed, or rotational speed while tripping.

Specify the operating mode you want to analyze by checking the appropriate box or boxes.

Trip speed is not used in the analysis unless a non-zero RPM is entered. Specify the coefficient of friction you want to use.

Click Advanced to specify coefficients of friction associated with different operating modes. Refer to “Advanced Options” on page 195 for more information.

Analyzing Normal Analysis Results Results for a Normal Analysis are presented in tables, plots, and reports. All results are available using the View Menu. In many cases, the same analysis results are presented in more than one form. For example, string tension data can be found in reports, plots, and tables. In general, the plots or tables present the data in a clearer, more concise format than the reports do. Depending on the number of operating modes selected, the reports can get very long and difficult to read unless you print them.

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Because of time restraints, this course does not discuss every available report, table and plot. If you have specific questions about a plot, table or report, ask your instructor or refer to the online help for more detail.

Analyzing Normal Analysis Results Using Plots There are several plots containing analysis results for a normal analysis. These include: • • • • • • •

Effective Tension True Tension Graph Torque Graph Side Force Graph Fatigue Graph Stress Graphs (for all operating modes) Position Graphs (only available if using stiff string model)

Using the Effective and True Tension Plots The Effective Tension plot displays the tension as calculated using the buoyancy method. Use this plot to determine when buckling may occur.

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The True Tension plot displays the tension as calculated using the pressure area method. Use this data for stress analysis.

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Using the Effective Tension Plot The View > Plot > Effective Tension graph displays the tension in all sections of the work string for the operating modes specified on the Normal Analysis Mode Data dialog as calculated using the buoyancy method. (Refer to “Buoyancy Method” on page 219 for more information.) The graph includes data for measured depths from the surface to the string depth specified on the Case > String Editor. The effective tension can be used to determine when buckling may occur. On the plot are curves indicating the loads required to buckle (helical or sinusoidal) the work string. When the effective tension load line for a particular operation mode crosses a buckling load line, the string will begin to buckle in the buckling mode corresponding to the buckling load line. The plot also indicates the tension limit for the work string component at the corresponding measured depth. If the effective tension curve for a particular operating mode exceeds the tension limit curve, the work string is in danger of parting at that point.

Using the True Tension Plot The View > Plot > True Tension graph displays the tension in all sections of the work string for the operating modes specified on the Normal Analysis Parameter > Mode Data dialog as calculated using the pressure area method. The graph includes data for measured depths from the surface to the string depth specified on the Case > String Editor. This data should only be used for stress analysis. If you want to determine when a worksting will fail due to tension, refer to the View > Plot > Effective Tension Graph.

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Using the Torque Graph

Component torque is input on the Case > String Editor.

The View > Plot > Torque Graph displays the torque in all sections of the workstring for the operating modes specified on the Parameter > Mode Data dialog for Normal Analysis. Data is included for measured depths from the surface to the string depth specified on the Case > String Editor spreadsheet. Make-up torque limit is also specified on this plot. The make-up torque is derated for tension and will therefore change with string depth. If the torque curve for a particular operating mode exceeds the torque limit at the same measured depth, the tool joints for the workstring are liable to over-torque or break. Torque limits for workstring components are specified on the Case > String Editor spreadsheet. Drilling fluid information is specified on the Case > Fluid Editor dialog, unless fluid information was specified on the Fluids Column dialog. The analysis also uses information specified on the Case > Wellpath Editor and Case > Hole Section Editor, and the Case > Torque Drag Setup Data and Parameter > Mode Data dialogs.

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Using the Fatigue Plot The View > Plot > Fatigue Graph presents the bending or buckling stress as a ratio of the fatigue limit.

High level of bending or buckling stresses

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Using Tables to Analyze Results Tables are a very useful form of viewing analysis results. Tabular results are organized in a way that makes it easy to quickly find the information you are looking for.

Using the Summary Loads Table The View > Table > Summary Loads table contains information pertaining to all sections of the work string and is a good place to begin your analysis. This table contains a load summary for the operating modes specified on the Normal Analysis Mode Data dialog. The View > Report > Summary Report contains similar information. For each operating mode, the following information is provided: stress mode indicator, buckling mode indicator, torque at rotary table, windup, surface measured weight, total stretch, and neutral point.

Stress column. An S indicates VonMises stress failure, a T indicates exceeding make-up torque and an F indicates fatigue.

Buckling Column. An H indicates helical buckling and an S indicates sinusoidal buckling.

What are the Loads For a Particular Operating Mode? For information on an individual operating mode, use View > Table > Load Data. The View > Report > Detail Report contains similar data. Information presented on the table includes measured depth, component type, distance from bit, internal pressure, external pressure, axial force (pressure area and buoyancy method), drag, torque, twist, stretch,

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sinusoidal buckling force, helical buckling force, buckling mode flag, and stress mode flag. The data in this table pertains to only one operating mode. In this case, it is the Tripping In operating mode.

The data in this table represents calculations at various depths.

What are the Stresses For a Particular Operating Mode? Use View > Table > Stress Data and select an operating mode.This table contains information pertaining to all sections of the work string. Data for each operating mode is specified on a separate table. This table contains information similar to the View > Plot > Stress Graph, including; measured depth, component type, distance from bit, hoop stress, radial stress, torsional stress, shear stress, axial stress, buckling

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stress, bending stress, BSMF, von Mises stress, von Mises stress ratio, and fatigue ratio. The data in this table pertains to only one operating mode. In this case, it is the Tripping In operating mode.

The data in this table represents calculations at various depths.

Analyzing Results Using Reports Reports are another form of presenting normal analysis results. However, if you will be analyzing more than one operating mode, using plots or tables is an easier way to view the results.

Using the Detailed Report Most of the information presented on the View > Report > Detail Report is available on tables, or in graphical form on plots. However, the Detail Report also includes the operating parameters and case data (as specified on the report options dialog) used in the analysis. Plots and tables do not include this information. When you are generating a report for an analysis of several operating modes, the information for each operating mode is separate from all other operating modes. For example, all tripping in analysis is kept separate from the tripping out analysis. Because there is a lot of data presented on the Detailed Report, it is recommended that reports be limited to analysis of one or two operating modes at a time. Otherwise the reports can get very long and difficult to read.

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Analysis Mode Methodology Each of the next four sections covers one of the analysis modes available in the Torque Drag module. In each section, the major analysis steps for the analysis mode are discussed. Within the analysis steps there may be a reference to a calculation. The name of the calculations are presented in italic for recognition. Many calculations apply to more than one analysis mode. To avoid duplicating information, the calculations are presented alphabetically in the section titled Supporting Information and Calculations. If you require more information about a particular calculation, please refer to “Supporting Information and Calculations” on page 217.

Normal Analysis In a Normal Analysis the calculations are performed for a work string, in a three-dimensional wellbore, at one bit depth, and with one set of operational parameters. If any of these items change (different bit depth, different work string, different mud weight, and so forth) then the Normal Analysis must be re-run. A Normal Analysis can investigate six load cases or operating conditions. These six load cases consist of tripping out, tripping in, rotating on bottom, rotating off bottom, sliding, and backreaming. During the analysis the following steps are performed. 1. The first step is to initialize all load cases with the loads at the bit, including torques and axial force. These parameters are input on the Normal Analysis Mode Data dialog. For a Normal Analysis, the loads at the bit must be input, so the surface loads can be calculated. 2. For both soft and stiff string models, the work string is broken into segments (elements) with a length equal to either a minimum of 30 feet or to the component length. This defines the segment to be analyzed. After the analysis of a segment is complete, the segment above is analyzed. This procedure is repeated until the entire string has been analyzed. For each segment, the following steps are performed: a) Interpolate the survey data at start and end of segment using the surveys entered in the Survey Editor (on the Case menu). Calculate the build rate, turn rate and dogleg severity. The

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minimum curvature method is used for all survey calculations. If the surveys had tortuosity applied, the “tortured” surveys are used. b) Determine the wellbore at this depth, and modify the tubular wall thickness based on the Pipe Wall Thickness Modification Due to Pipe Class calculations (page 233). c) Compute the weight per foot of the segment in fluid and at the wellbore angle using the Buoyed Weight calculations (page 221). Because the work string is lying in a wellbore surrounded by fluids, there are resultant hydrostatic pressures acting on all interior and exterior surfaces of the pipe. The Buoyed Weight calculations determine the resultant weight of the segment considering the hydrostatic pressures acting on it. d) Determine the force required to buckle the segment in the wellbore using the Critical Buckling Force calculations (page 222). The critical buckling force is the axial force required to be exerted on a work string to initiate buckling. Buckling first occurs when compressive axial forces exceed a critical buckling force. The axial force computed using the Buoyancy Method (Axial Force calculations, page 218) is used to compare with the critical buckling force to determine the onset of buckling. This is because the critical buckling force calculations are based on the same assumptions regarding hydrostatic pressure. e) Calculate the normal (side) force using the Side Force calculations for the Soft String Model (page 235), or for the Stiff String Model (page 237). The side force or normal force is a measurement of the force exerted by the wellbore onto the work string. f) Calculate the drag acting on the segment using the Drag Force calculations (page 226). The magnitude of the drag force is influenced by the selection of Friction Factor. g) Determine the axial forces acting on the segment using the Axial Force calculations (page 218). Axial forces act along the axis of the work string. h) If buckling occurs, determine the additional side force due to buckling by using the Additional Side Force calculations (page 217).

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i) Calculate string torque using the Torque calculations (page 244). Any input bit torque will be added to calculated torque. j) Determine stresses using the Stress calculations (page 239). k) Perform Fatigue calculations (page 228). l) Perform Twist calculations (page 246) and Stretch calculations (page 242). 3. Apply Sheave Friction Correction calculations (page 234) to tension at the surface. This correction is only made if specified on the Torque Drag Setup dialog. 4. Compute pick up and slack off for tripping load cases. 5. Calculate maximum weight on bit to buckle (sinusoidal and helical) the work string, and maximum allowable overpull.

Calibrate Friction Analysis Calibrate Friction Analysis calculates the coefficient of friction along the wellbore using actual (field) data collected while drilling. This provides a means of calibrating the program model against actual field results. The following are an overview of the calculations performed. 1. The work string is broken into the minimum of 30 feet, or the component length. This is the segment to be analyzed. After the analysis of a segment is complete, the segment above it will be analyzed. This procedure is repeated until the entire string has been analyzed. a) Interpolate survey at start and end of segment. Calculate build rate, turn rates and dogleg severity. The minimum curvature method is used for all survey calculations. If the surveys had Tortuosity (page 244) applied, the “tortured” surveys are used. b) Determine the wellbore at this depth, and apply Pipe Wall Thickness Modification Due to Pipe Class calculations (page 233). c) Compute the weight per foot of the segment in fluid and at the wellbore angle using the Buoyed Weight calculations (page 221). Because the work string is lying in a wellbore surrounded by fluids, there are resultant hydrostatic pressures acting on all

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interior and exterior surfaces of the pipe. The Buoyed Weight calculations determine the resultant weight of the segment considering the hydrostatic pressures acting on it. d) Estimate the coefficient of friction for either the cased hole, or the open hole, or both. For each of the load cases, the following steps (1 through 5) are performed until the calculated torque and hookloads match the input or field values. If the values don’t match, another coefficient of friction is estimated, and the following steps are performed again. 1. Calculate the normal (side) force using the Side Forcepage 235 calculations for the soft string model or for the stiff string model. The side force or normal force is a measurement of the force exerted by the wellbore onto the work string. 2. Calculate the drag acting on the segment using the Drag Force calculations (page 226). The magnitude of the drag force is influenced by the selection of the Friction Factor. 3. Determine the axial forces acting on the segment using the Axial Force calculations (page 218). Axial forces act along the axis of the work string. 4. Calculate string torque using the Torque calculations (page 244). 5. Apply Sheave Friction Correction calculations (page 234) to tension at the surface. This correction is only made if specified on the Torque Drag Setup dialog.

Drag Chart Analysis Drag Chart Analysis performs essentially the same analysis steps as performed in the Normal Analysis. However, in a Drag Chart analysis, you can specify a range of bit depths. (A Normal Analysis is performed at a single bit depth.) For each bit depth in the Drag Chart Analysis, the largest torque or measured weight occurring anywhere in the work string is recorded. This information is then available in graphical output. The following is a brief overview of the calculations.

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1. Begin with the first bit depth. The first step is to initialize all load cases with the loads at the bit, including torques and axial force. These parameters are input on the Run Parameters Data dialog. 2. Next, the work string is broken into the minimum of 30 feet, or the component length. This is the segment that will be analyzed. After the analysis of a segment is complete, the segment above it will be analyzed. This procedure is repeated until the entire string has been analyzed. a) Interpolate survey at start and end of segment. Calculate build, turn rates, and dogleg severity. The minimum curvature method is used for all survey calculations. If the surveys had tortuosity applied, the “tortured” surveys are used. b) Determine the wellbore at this depth, and apply Pipe Wall Thickness Modification Due to Pipe Class calculations (page 233). c) Compute the weight per foot of the segment in fluid and at the wellbore angle using the Buoyed Weight calculations (page 221). Because the work string is lying in a wellbore surrounded by fluids, there are resultant hydrostatic pressures acting on all interior and exterior surfaces of the pipe. The Buoyed Weight calculations determine the resultant weight of the segment considering the hydrostatic pressures acting on it. d) Determine the force required to buckle the segment in the wellbore using the Critical Buckling Force calculations (page 222). The critical buckling force is the axial force required to be exerted on a work string to initiate buckling. Buckling first occurs when compressive axial forces exceed a critical buckling force. The axial force computed using the Buoyancy Method is used to compare with the critical buckling force to determine the onset of buckling. e) Calculate the normal (side) force using the Side Force calculations for the Soft String Model (page 235), or for the Stiff String Model (page 237). The side force or normal force is a measurement of the force exerted by the wellbore onto the work string. f) Calculate the drag acting on the segment using the Drag Force calculations (page 226). The magnitude of the drag force is governed by the selection of Friction Factor (page 232).

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g) Determine the axial forces acting on the segment using the Axial Force calculations (page 218). Axial forces act along the axis of the work string. h) If buckling occurs, determine the additional side force due to buckling by using the Additional Side Force calculations (page 217). i) Calculate string torque using the Torque calculations (page 244). 3. Apply Sheave Friction Correction calculations (page 234) to tension at the surface. This correction is only made if specified on the Torque Drag Setup dialog. 4. Determine the measured weight at the surface, and the maximum torque at any point in the work string with the bit at the specified depth. Repeat the calculations with the next bit depth.

Top Down Analysis Top Down Analysis allows the specification of string forces from the surface. You can use this mode to determine downhole forces acting on the work string when you know the surface forces. This analysis mode is in many ways the opposite of the Normal Analysis. A Normal Analysis calculates the forces at the surface based on known forces acting at the bit. You may want to use this analysis mode to analyze coiled tubing operations. In the case of coiled tubing, you are driving tubing into the hole with known injector forces at the surface. This analysis mode provides a means of determining the tension or compression forces acting on the tubing downhole. You can specify a tension (positive) or compressive (negative) injector force at the surface. You can also use this analysis mode to analyze stuck pipe situations. When a pipe is stuck downhole, you know the forces at the surface, but the downhole loads must be estimated. You may want to know the required surface forces to achieve a specific force to trip a jar. You may want to apply a tension or torque at the surface, and from the resulting pipe stretch or twist, you can calculate the stuck point.

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1. The first step is to initialize with the loads at the surface, including torques and axial force. These parameter are input on the Top Down Analysis Mode Data dialog. 2. Next, the work string is broken into the minimum of 30 feet, or the component length. This is the segment that will be analyzed. After the analysis of a segment is complete, the segment below it will be analyzed. This procedure is repeated until the entire string has been analyzed (from the surface down the string). a) Interpolate survey at start and end of segment. Calculate build and turn rates, and the dogleg severity. The minimum curvature method is used for all survey calculations. If the surveys had tortuosity applied, the “tortured” surveys are used. b) Determine the wellbore at this depth, and apply Pipe Wall Thickness Modification Due to Pipe Class calculations (page 233). c) Compute the weight per foot of the segment in fluid and at the wellbore angle using the Buoyed Weight calculations (page 221). Because the work string is lying in a wellbore surrounded by fluids, there are resultant hydrostatic pressures acting on all interior and exterior surfaces of the pipe. The Buoyed Weight calculations determine the resultant weight of the segment considering the hydrostatic pressures acting on it. d) Determine the force required to buckle the segment in the wellbore using the Critical Buckling Force calculations (page 222). The critical buckling force is the axial force required to be exerted on a work string to initiate buckling. Buckling first occurs when compressive axial forces exceed a critical buckling force. The axial force computed using the Buoyancy Method is used to compare with the critical buckling force to determine the onset of buckling. e) Calculate the normal (side) force using the Side Force calculations for the Soft String Model (page 235), or for the Stiff String Model (page 237). The side force or normal force is a measurement of the force exerted by the wellbore onto the work string. f) Calculate the drag acting on the segment using the Drag Force calculations (page 226). The magnitude of the drag force is governed by the selection of Friction Factor (page 232).

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g) Determine the axial forces acting on the segment using the Axial Force calculations (page 218). Axial forces act along the axis of the work string. h) If buckling occurs, determine the additional side force due to buckling by using the Additional Side Force calculations (page 217). i) Calculate string torque using the Torque calculations (page 244). Any input bit torque will be added to the calculated torque. j) Determine stresses using the Stress calculations (page 239). k) Perform Fatigue calculations (page 228). l) Perform Twist calculations (page 246) and Stretch calculations (page 242). 3. Apply Sheave Friction Correction calculations (page 234) to tension at the surface. This correction is only made if specified on the Torque Drag Setup dialog. 4. Compute the pick up and slack off. 5. Calculate maximum weight on bit required to buckle (sinusoidal and helical) the work string, and maximum allowable overpull.

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Supporting Information and Calculations The calculations and information in this section are presented in alphabetical order using the calculation or topic name. The material contained in this section is intended to provide you more detailed information and calculations pertaining to many of the steps presented during the descriptions of the analysis mode methodologies. If the information in this section does not provide you the detail you require, please refer to “References” on page 250 for additional sources of information pertaining to the topic you are interested in.

Additional Side Force Due to Buckling Once buckling has occurred, there is an additional side force due to increased contact between the wellbore and the work string. For the soft string model, the following calculations are used to compute the additional side force. These calculations are not included in a stiff string analysis because the stiff string model considers the additional force due to buckling in the derivation of the side force.

Sinusoidal Buckling Mode No additional side force due to buckling is added.

Helical Buckling Mode

Fadd =

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rFaxial 4 EI

2

217


Where:

Fadd

= Additional side force

Faxial

= Axial compression force calculated using the buoyancy method

E I r

= Young’s modulus of elasticity = Moment of Inertia = Radial clearance between wellbore and work string

Axial Force There are two calculation methods to determine the axial force: the buoyancy method and the pressure area method. In checking for the onset of buckling, the buoyancy method is used. This is because the Critical Buckling Force calculations (page 222) are based on the same assumptions regarding hydrostatic pressure. For stress calculations, the pressure area method is used. Both methods predict the same measured weight at the surface because there is no hydrostatic force acting at the surface. Below the surface, the axial force calculated using each method will be different. Consider a work string “hanging in air,” or more specifically, in a vacuum. Some of the string weight is supported at the bottom by a force (specifically, the weight on bit). In this situation, the upper portion of the string is in axial tension, and the lower portion of the string is in axial compression. Somewhere along the string there is a point where the axial force changes from tension to compression, and the axial stress is zero. This is the neutral point. In this simple case, the distance from the bottom of the string up to the neutral point can be calculated by dividing the supporting force at the bottom (specifically, the weight on bit) by the weight of the string per unit length. In other words, the weight of the string below the neutral point is equal to the supporting force. In a normal drilling environment, the string is submerged in a fluid. The fluid creates hydrostatic pressure acting on the string. Two different neutral points can be calculated as a result of the handling of the hydrostatic forces. The buoyancy method includes the effects of buoyancy, while the pressure area method does not.

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The pressure area method computes the axial forces in the work string by calculating all the forces acting on the work string, and solving for the neutral point using the principle of equilibrium. Using this method, the axial force and axial stress is exactly zero at the neutral point. Using the buoyancy method, the axial force at the neutral point is not zero. The axial force and stress is equal to the hydrostatic pressure at the depth of the neutral point. Because hydrostatic pressure alone will never cause a pipe to buckle, the buoyancy method is used to determine if and when buckling occurs.

Buoyancy Method The buoyancy method is used to determine if buckling occurs.

[

]

Faxial = ∑ LWair Cos (Inc ) + Fdrag + ∆Farea − Fbottom − WWOB + FBS

Pressure Area Method The pressure area method is used to calculated stress.

[

]

Faxial = ∑ LWair Cos (Inc ) + Fdrag + ∆Farea − Fbottom − WWOB

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L W air

= Length of drillstring hanging below point (ft)

Inc F bottom

= Inclination (deg)

= W eight per foot of the drillstring in air (lb/ft)

W WOB

= Bottom pressure force, a com pression force due to fluid pressure applied ov er the cross sectional area of the bottom com ponent = Change in force due to a change in area at junction between two com ponents of different cross sectional areas, such as the junction between drill pipe and heav y weight or heav y weight and drill collars. If the area of the bottom com ponent is larger the force is a tension, if the top com ponent is larger the force is com pression. = W eight on bit (lb) (0 for tripping in & out)

F drag

= Drag force (lb)

FBS

= Buckling Stability Force = PressExternal*AreaExternal – PressInternal*AreaInternal

F area

Pipe:

Area External = π/4*(0.95*BOD*BOD + 0.05*JOD*JOD) AreaInternal = π/4*(0.95*BID*BID + 0.05*JID*JID) AreaExternal = π/4*(BOD*BOD) Collar: AreaInternal = π/4*(BID*BID) PressExternal = AnnulusSurfacePress + Σ (AnnulusPressGrad * TVD) PressInternal = StringSurfacePress + Σ (StringPressGrad * TVD)

Bending Stress Magnification (BSM) Bending stress magnification (BSM) will be applied to the calculated bending stresses if you have checked the BSM box on the Torque Drag Setup Data dialog. The magnitude of the BSM is reported in the stress data table of the Normal Analysis Detail Report, and in the Top Down Analysis Detail Report. When a drill string is subjected to either tensile or compressive axial loads, the maximum curvature of the drillpipe body exceeds that of the hole axis curvature. The drillpipe sections conform to the wellbore curvature primarily through contact at the tool joints. In both tensile and compressive axial load cases the average curvature between the tool joints is not changed, but the local changes of curvature due to

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straightening effects of tension or the buckling effects of compression may be many times the average value. Therefore, to accurately calculate the bending stress in the pipe body requires the determination of these local maximum curvatures. The bending stress magnification factor (BSM) is defined as the ratio of the maximum of the absolute value of the curvature in the drillpipe body divided by the curvature of the hole axis. The BSM is applied as a multiplier on the bending stress calculation. This modified bending stress is then used in the calculation of the von Mises stress of the drillpipe.

Buoyed Weight The surface pressure and mud densities input on the Fluids Column tabs, or the mud weight input on the Fluid Editor are used to determine the pressure inside and outside of the work string. Using the equations listed below, these pressures are used to determine the buoyed weight of the work string. The buoyed weight is then used to determine the forces and stresses acting on the work string in the analysis.

WBuoy = WAir − WFluid

WFluid = (MWAnnular ∗ AExternal) − (MWInternal ∗ AInternal )

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For components with tool joints

A External

= π 4 ∗ [0.95 ∗ (OD Body

A Internal = π 4 ∗ [ 0 .95 ∗ (ID Body

)

2

)

2

+ 0.05 ∗ (OD Jo int

+ 0 . 05 ∗ (ID Jo int

)2 ]

)2 ]

Note: The constants 0.95 and 0.5 are used to assume that 95% of the component length is pipe body, and 5% is tool joint.

For components without tool joints A Internal = π 4 ∗ (ID Body

AExternal = π 4 ∗ (OD Body

) ) 2

2

Where:

OD Body = Outside diameter of component body

OD Jo int = Outside diameter of tool joint ID Body = Inside diameter of component body

ID Jo int = Inside diameter of tool joint AExternal = External area of the component AInternal = Internal area of the component WFluid = Weight per foot of displaced fluid W Buoy = Buoyed weight per foot of component

MW Annular = Annular mud weight at component depth in the wellbore MWInternal = Internal mud weight at component depth inside the component

Critical Buckling Forces The critical buckling force is the axial force required to be exerted on a work string to initiate buckling. Buckling first occurs when compressive axial forces exceed a critical buckling force. The axial force computed using the Buoyancy Method is used to compare with the critical buckling force to determine the onset of buckling.

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The critical buckling forces can be found listed by component type and measured depth in the sinusoidal buckling and helical buckling columns of the Normal Analysis Detail Report or the Top Down Analysis Detail Report. The values in these two columns can be compared to the Drill String Axial Force - Buoyancy column to determine if the component is bucked at that depth. If the compressive force indicated in the Buoyancy column exceeds that of either the sinusoidal buckling or helical buckling column, the component is buckled. If buckling occurs, an S indicating sinusoidal buckling, an H indicating helical buckling, or an L indicating lockup will be listed in the B column. Different critical buckling forces are required to initiate the sinusoidal and helical buckling phases. Calculations for the critical buckling force also vary depending on the analysis options selected on the Torque Drag Setup Data dialog.

Straight Model Calculations The Straight Model divides the work string into 30 foot sections. The inclination and azimuth of these sections change along the well as described by the wellpath data and the approximate 3D well shape. However, each 30 foot section is assumed to be “straight” or of constant inclination. By contrast, the curvilinear model takes into account the inclination (build or drop) change within each 30 foot section.

Critical Inclination to Select Buckling Model

[

Θ c = Sin −1 (1 . 94 2 ) ∗ r ∗ (W EI ) If

(Inc

2

13

]

> Θ C ) , then: F S = 2[Sin (Inc )EIW / r ]

12

If

(Inc

< Θ C ) , then:

(

F S = 1 .94 EIW

)

2 13

Curvilinear Model For a torque drag analysis, the work string is divided into 30 foot sections. The straight model assumes each section is of constant inclination. The curvilinear model takes into account the inclination (build or drop) change within each 30 foot section. Landmark

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In hole sections where there is an angle change, compression in the pipe through the doglegs causes extra side force. The additional side force acts to stabilize the pipe against buckling. An exception is when the pipe is dropping angle.

In a build section of the well:

EIW Sin (Inc )  2 EI κ   EI κ  FS =  +2   + r  r   r  2

In a drop section of the well:

κ test = if

rW Sin (Inc ) EI

(κ ≥ κ test ) then, EIW Sin ( Inc )  2 EI κ   EI κ  FS =  −2   − r  r   r  2

if

(κ < κ test ) then,

EIW Sin (Inc )  2 EI κ   EI κ  FS = −  +2   + r  r   r  2

Loading and Unloading Models In SPE 36761, Mitchell derives the loading method. The idea presented is that for compressive axial loads between 1.4 and 2.8 times the sinusoidal buckling force, there is enough strain energy in the pipe to sustain helical buckling, but not enough energy to spontaneously change from sinusoidal buckling to helical buckling. If you could reach in and lift the pipe up into a helix, it would stay in the helix when you let go. In an ideal situation without external disturbances the pipe would stay in a sinusoidal buckling mode until the axial force reached 2.8 times the sinusoidal buckling force. At this point, the pipe would transition to the helical buckling mode. This is the “loading” scenario. Once the pipe is in the helical buckling mode, the axial force can be reduced to 1.4 times the sinusoidal buckling force, and the helical mode will be maintained. If the axial force falls below 1.4 times the sinusoidal buckling force, the pipe will fall out of the helix into a sinusoidal buckling mode. This is the “unloading” scenario.

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In the figure above, in stage 1 the compressive load is increased from the force required for sinusoidal buckling to the threshold force where the pipe snaps into a helically buckled state. This is the “loading” force. Stages 2 and 3 represent the reduction of the compressive load to another threshold force to snap out from helically buckled into a sinusoidal buckled state. This is the “unloading” force. Taking friction into consideration, we can imagine buckling friction acts a bit like glue. It gives resistance when the pipe is pushed into buckling (loading) and it also provides resistance to release the pipe from buckling (unloading). But when the pipe is rotating the “glue” bond is broken, and gives no resistance. Where friction is effective, the transitions from sinusoidal to helical and vice versa are more explosive because the pipe picks up more spring energy because the friction prevents free pipe movement until the stored energy is enough to break the friction bond.

Loading Model

FH = 2.828427 FS

Unloading Model

FH = 1.414FS

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225


Where:

FS

= C o m p r e s s io n fo r c e to in d u c e o n s e t o f s in u s o id a l b u c k lin g

FH I E W Inc κ r

= C o m p r e s s io n fo r c e to in d u c e o n s e t o f h e lic a l b u c k lin g = M o m e n t o f in e r tia l fo r c o m p o n e n t = Y o u n g ’s m o d u lu s o f e la s tic ity = T u b u la r w e ig h t in m u d = W e llb o r e in c lin a tio n = C u r v a tu r e in th e v e r tic a l p la n e ( b u ild o r d r o p ) = R a d ia l c le a r a n c e b e tw e e n w e llb o r e a n d w o r k s tr in g , in

ID C asin gInOpenHole OD ToolJoint r = --------------------------------------------- – ---------------------------2 2

Drag Force Calculations The drag force acts opposite to the direction of motion. The direction of the drag force is governed by the type of analysis being performed. The drag force may be acting up the axis of the pipe, down the axis of the pipe, or acting in a tangential direction resisting the rotation of the pipe. The drag force is calculated using the following equation.

FD = FN ∗ µ ∗

T V

Where:

T

226

= Trip speed

diameter ∗ π ∗

RPM 60

A

= Angular speed =

V

= Resultant speed =

FN

= Side or norm al force

µ

= Coefficient of friction (friction factor)

FD

= Drag force

WELLPLAN

(T

2

+ A2

)

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The side force or normal force is a measurement of the force exerted by the wellbore onto the work string. In the diagram below, the forces acting on a small segment of work string lying in an inclined hole are shown. In this simple diagram, the segment is not moving. From this diagram we can see that the normal force acts in a direction perpendicular to the inclined surface. The weight of the work string acts downward in the direction of gravity. Another force, the drag force, is also acting on the segment. The drag force always acts in the opposite direction of motion. The segment does not slide down the inclined plane because of the drag force. The magnitude of the drag force depends on the normal force, and the coefficient of friction between the inclined plane and the segment. The coefficient of friction is a means to define the friction between the wellbore wall and the work string.

Where: FN = Normal Force FD = Drag Force W = Weight of segment Landmark

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Fatigue Calculations WELLPLAN torque drag includes fatigue analysis because it is a primary cause of drilling tubular failure. A fatigue failure is caused by cyclic bending stresses when the pipe is run in holes with doglegs. The source of fatigue failure is micro fractures between the crystal structures of the material caused in the construction of the material. These cracks are widened by successive stress reversals (tensile/compressive) in the body of the cylinder. The following five steps are applied in the Torque Drag analysis of fatigue loading and prediction. Cyclic stresses are those components of stress that change and reverse every time the pipe is rotated. In Torque Drag, only bending and buckling stresses go through this reversal. In the stiff string model the buckling stresses are integrated with the pipe curvature and hence included in bending; the soft string model treats buckling stress independent to bending stress and adds the two together for fatigue analysis. Bending stresses are caused by pipe running through a curved hole. On one side of the pipe is bent into tension and the other side of the pipe is bent into compression (see diagram following). Bending stresses are a maximum at the outside of the pipe body and undergo a simple harmonic motion as the pipe rotates.

Apply Bending Stress Magnification Factor calculations (page 220). Bending stress concentrates close to the tool joints in externally upset pipe when the pipe is in tension. This magnifies the bending radius in the section of pipe close to the tool joints.

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Establish A Fatigue Endurance Limit For The Pipe Fatigue endurance limit is not a constant value that is related to the yield strength of the pipe. It cannot be associated with the material grade of the pipe. There are also bending stress concentrations in the tubular due to the design of tool-joints and the shape of upsets in the body of the pipe apart from those considered in the bending stress magnification factor.

Drillpipe

25-35 Kpsi This is a general value for continuous tubular steel.

Heavy Weight

18-25 Kpsi More stress concentration in tool joint

Drill Collars

12-15 Kpsi Includes drill collars and other non upset BHA components, like jars, stabilizers, MWD, and so forth.

Casings

5-20 Kpsi Depends on connectors: 5 for 8 round, 20 for premium

Non externally upset tubulars like collars and casing will have maximum concentration of bending stress at the tool joint. The fatigue endurance limit needs to be reduced if the steel is used in a corrosive environment like saline (high chloride) or hydrogen sulfide environment.

Derate The Fatigue Endurance Limit For Tension The crack widening mechanism that causes fatigue is strongly influenced by tension in the pipe. A simple empirical mechanism is used to reduce the fatigue endurance limit for tensile stress as a ratio of the tensile yield stress. This is known as the Goodman relation.

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F AY = σ MY AE If F AB > 0.0 then,



FAB FAY

σ FL = σ FEL 1 − 

  (Tension) 

Else,

σ FL = σ FEL

(Compression)

R F = (σ BEND + σ BUCK

AINTC =

)σ

FL

(ID ) 4

π

2

B

AE = AEXT − AINT AEXTP = AINTP = AEXTC = AINTC =

230

π 4

π 4

(0.95OD (0.95 ID

2 B

2 B

+ 0.05OD J

+ 0.05 ID J

2

2

)

)

(OD ) 4

π

2

B

(ID ) 4

π

2

B

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Where:

F AY

= Axial force required to generate the yield stress, (lb)

F AB

= Axial force (Buoyancy M ethod), (lb)

σ FL

= Fatigue lim it, (psi)

σ MY

= M inim um yield stress specified by G rade , (psi)

σ FEL

= Fatigue endurance lim it, (psi) (For pipe and heav y weight,

σ BEND

= Bending stress, (psi) (Corrected by BSM F)

σ BUCK

= Buckling stress, (psi) (only if buckling occurs)

RF

= Fatigue Ratio

AE

= Effectiv e sectional area, in

A EXT

= External area of pipe, heav y weight or collar com ponent, in

this is input. All other com ponents assum e = 35,000 psi

2

A INTC

( ) = Internal area of pipe, heav y weight, or collar com ponent, (in ) = Pipe and heav y weight external area, (in ) = Pipe and heav y weight internal area, (in ) = Collar external area, (in ) = Collar external area, (in )

OD B

= Body outside diam eter, (in)

OD J

= Joint outside diam eter, (in)

ID B

= Body inside diam eter, (in)

ID J

= Joint inside diam eter, (in)

A INT A EXTP A INTP A EXTC

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( )

2

2

2

2

2 2

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231


Compare The Cyclic Stress Against The Derated Fatigue Endurance Limit The fatigue ratio is the combined bending and buckling stress divided by the fatigue endurance limit. Some judgment is required in using the fatigue endurance limit (FEL), because the limit is normally determined for a number of cycles of pipe rotation. The number of cycles for the fatigue endurance limits is approximately taken at 107 rotations; this is the level of cyclic stress beyond which the material is immune to fatigue failure. This is normally equivalent to the pipe drilling for 100000' at 60ft/hr at 100 rpm. The relationship between fatigue stress (S) and number of cycles to failure (N) is known as the S-N curve. The following chart is an idealized S-N curve for G105 pipe that has a yield of 105 Kpsi and a fatigue endurance limit of 30 Kpsi.

Using the chart you can see that a pipe may yield at a lower number of cycles at an intermediate stress between the fatigue endurance limit and the tensile stress limit.

Friction Factors A friction factor is sometimes referred to as the coefficient of friction. The friction factor represents the prevailing friction between the wellbore or casing and the work string. Higher coefficients of friction

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result in greater resistance to the movement of the work string as it is run in, pulled out, or rotated in the wellbore. A friction factor of zero implies there is no friction in the well, which is an impossible situation. A friction factor of one suggests all of the normal (contact) force has been translated into drag force. Refer to the Drag Force calculations (page 226) for related information. Friction depends on the two surfaces in contact, as well as the lubrication properties of the drilling fluid. In addition to friction, the results of physical mechanisms acting on the work string are reflected in the selection of the friction factor. There are a number of physical mechanisms, including stabilizer gouging, key seats, and swelling formations, that contribute to the torque and drag of the work string. These mechanisms can cause the hook loads and torques to be higher or lower than expected. The wellbore path (doglegs or tortuosity) can also contribute to the loading forces on a work string. Refer to Tortuosity in this section (page 244) for more information.

Models The Torque Drag module offers you the choice of two methods to use to model the string in the wellbore. The soft string model has been the basis of the WELLPLAN Torque Drag analysis for years. This model is commonly used throughout the industry for this type of analysis. The stiff string model was added to the module with the latest release of the software. Both models analyze the string in 30-foot sections. The primary difference between the models is the method of calculating the normal force acting on the string as a result of the string placement in the wellbore. Each of the models are described in the following sections.

Pipe Wall Thickness Modification Due to Pipe Class Drill pipe wall thickness is modified according to the class specified for the pipe on the String Editor. The class specified indicates the wall thickness modification as a percentage of the drillpipe outside diameter. Drill pipe classes can be entered or edited on the Class option of the Tubular Properties submenu of the Tools Menu. The outside diameter is modified as follows:

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ODnew = c ∗ ODold + IDold (1 − c ) Where:

OD new = Calculated outside diam eter based on pipe class c

=

%WallThickn ess and is based on pipe class specified 100

OD old = O utside diam eter as specified on the String Editor ID old

= Inside diam eter as specified on the String Editor

Sheave Friction Sheave friction corrections are applied to all measured weight calculations when you have indicated on the Torque Drag Setup Data dialog that you want to apply this correction.

Lr =

Ll =

n(e − 1)(H r + Wtb ) 1   e1 − n   e 

n(1 − e )( H l + Wtb ) 1 − en

(

)

Where:

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Lr

= Weight indicator reading while raising

Ll

= Weight indicator reading while lowering

Hr

= Hook load while raising, calculated in analysis

Hl

= Hook load while lowering, calculated in analysis

Wtb n e

= Weight of travelling block, user input = Number of lines between the blocks = Individual sheave efficiency

Side Force for Soft String Model The side force or normal force is a measurement of the force exerted by the wellbore onto the work string. In the diagram below, the forces acting on a small segment of work string lying in an inclined hole are shown. In this simple diagram, the segment is not moving. From this diagram we can see that the normal force acts in a direction perpendicular to the inclined surface. The weight of the work string acts downward in the direction of gravity. Another force, the drag force, is also acting on the segment. The drag force always acts in the opposite direction of motion. The segment does not slide down the inclined plane because of the drag force. The magnitude of the drag force depends on the normal force, and the coefficient of friction between the inclined

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235


plane and the segment. The coefficient of friction is a means to define the friction between the wellbore wall and the work string.

FN =

(FT ∆α Sin(Φ ))2 + (FT

∆Θ + WL Sin(Φ ))

2

Where:

FN

= Normal or side force

FT

= Axial force at bottom of section calculated using Buoyancy Method

∆α Φ ∆Θ L W

= Change in azimuth over section length = Average inclination over the section = Change in inclination over section length = Section length = Buoyed weight of the section

Where: FN= Normal Force FD = Drag Force W = Weight of segment

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Soft String Model The soft string model is based on Dawson’s cable model, or soft string model. As the name implies, in this model the work string (such as drillstring or casing, and so forth) is considered to be a flexible cable or string with no associated bending stiffness. Since there is no bending stiffness, there is no standoff between the BHA and the wellbore wall due to stabilizers or other upsets. When determining contact forces, the work string is assumed to lie against the side of the wellbore. However, within the soft string analysis it is actually considered to follow the center line of the wellbore. When determining the contact or normal force, the contact between the string and the wellbore is assumed to occur at the midpoint of each string segment.

Stiff String Model The stiff string model uses the mathematical finite element analysis to determine the forces acting on the string. This model considers the tubular stiffness and the tubular joint-to-hole wall clearance. The model modifies the stiffness for compressive forces. Like the soft string model, it calculates single point weight concentrations so determining the contact force per unit area is not possible. Stiff String analysis should be used to complete the following tasks: • • • •

Evaluate a work string containing stiff tubulars run in a well with an build rate of at least 15 deg/100 ft. Analyze running stiff casing in a well. Observe buckling using the Position Plot. Analyze work string containing upsets found on stabilizers or friction reduction devices.

The stiff string model analyzes the string by dividing it into sections (elements) equal to the lesser of the component length or 30 feet. The model computes the side force at the center point of each element. The side force is used to compute the torque and drag change from one element to the next element. The analysis of each element involves analyzing the nodes defining the end points of each element. The detailed analysis of each node involves creating a local mesh of 10 to 20 elements around the node. Each

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237


element is given the same dimensions and properties as the corresponding full drill string portion. If the node length exceeds the maximum column-buckling load for the section, the node is further broken into fractional lengths to keep each section below the buckling threshold. This is why the analysis may take considerably longer when large compressive loads are applied. This short section is solved by solving each individual junction node for moments and forces, then displacing it to a point of zero force. If this position is beyond the hole wall, a restorative force is applied to keep it in the hole. This process is repeated for each node in the short beam until they reach their “relaxed” state. The stiff string produces slightly different results when run “top down” or “bottom up.” The difference is explained because the direction of analysis is reversed. The length of beam selected for each stiff analysis has been selected to optimize speed while maintaining reliable consistent results. The following illustrations depict an inclined beam section with length L. P is the axial force, and Fv, F1, and F2 are the calculated ends or contact forces caused by weight W.

M = End Moment Fv = End Force

I L P Fv

M1

M2 W

F1

F2 L

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Stress In the analysis, many stress calculations are performed using the following equations. These calculations include the effects of: z

Axial stress due to hydrostatic and mechanical loading

z

Bending stress approximated from wellbore curvature

z

Bending stress due to buckling

z

Torsional stress from twist

z

Transverse shear stress from contact

z

Hoop stress due to internal and external pressure

z

Radial stress due to internal and external pressure

Calculated stress data is available on the Stress Graph, Summary Report or Stress Data table.

σ ij = stress

j = location

i = stress type

Stress types: r = Radial s = Transverse shear h = Hoop t = Torsion a = Axial

Location: 1 = outside pipe wall 2 = inside pipe wall

Von Mises Stress

σ VM =

(σ

− σ hj ) + (σ aj − σ rj ) + (σ hj − σ aj ) + 6σ sj + 6σ tj 2

rj

2

2

2

2

2

Note: The von Mises stress is calculated on the inside and outside of the pipe wall. The maximum stress calculated for these two locations is presented in the reports, graphs, and tables.

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239


Radial Stress

σ r1 = − Pe σ r 2 = − Pi

Transverse Shear Stress

σ s1 = σ s 2 =

2 Fn A

Hoop Stress

[ = [(r

( ) ] (r )P − 2 r P (r

σ h1 = 2 ri Pi − ri + ro Pe σ h2

i

2

2

2

+ ro

2

2

2

i

o

e

2

− ri

2

− ri

o

o

2

2

) )]

Torsional Stress

σ t 1 = 12 ro T J σ t 2 = 12 ri T J

Bending Stress

σ bend 1 = ro EκM 68754.9 σ bend 2 = ri EκM 68754.9

Buckling Stress (only calculated if buckling occurs)

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σ buck 1 = ro R c Fa 2 I σ buck 2 = − ri R c Fa 2 I

Axial Stress (tension + bending + buckling)

σ a 1 = F a A + σ bend 1 + σ buck 1 σ a 2 = F a A + σ bend 2 + σ buck 2

Where:

ri

= Inside pipe radius (in)

ro

= O utside pipe radius (in), as m odified by the pipe class

Fn

= Norm al (side) force, (lb)

Fa

= Axial force (lb) as calculated with pressure area m ethod

T E Pi

= Torque (ft-lb)

Pe

= Pipe external pressure (psi)

κ

= M odulus of elasticity (psi) = Pipe internal pressure (psi)

= W ellbore curv ature as dogleg sev erity (deg/100ft) for soft string m odel. Stiff string m odel calculates local string curv ature.

J = Polar m om ent of inertia W here:

( 32 (J

J body = π 32 B od − B id J

jo int

=π

4

4 od

− J id

4 4

) )

B od = body outside diam eter, in B id = body inside diam eter, in J od = joint outside diam eter, in J id = joint inside diam eter, in

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A I Rc

= Cross sectional area of component

M

= Bending Stress Magnification Factor

= Moment of inertia = Maximum distance from workstring to wellbore wall (in)

Stretch Total stretch in the work string is computed as the sum of three components. These three components consider the stretch due to axial load, buckling, and ballooning. Ballooning is caused by differential pressure inside and outside of the work string. Total Stretch = ∆LHL + ∆LBuck + ∆LBalloon

Stretch due to axial load This term is based on Hooke’s Law. The first term reflects the constant load in the string, while the second term reflects the linear change in the load.

∆LHL =

∆F ∗ L F ∗L + A∗ E 2∗ A∗ E

Where:

∆LHL F ∆F A E

= Change in length due to the Hooke’s Law mechanism = Axial force as determined by the pressure area method = Change in pressure area axial force over component length = Cross sectional area of component = Young’s Modulus of component

Stretch due to buckling If buckling occurs, the additional stretch in the buckled section of the work string is calculated using the following equation.

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∆LBuck =

r 2 ∗ F ∗ L r 2 ∗ ∆F ∗ L + 4∗ E ∗ I 8∗ E ∗ I

Where:

∆L Buck = Change in length due to buckling F ∆F E I r

= Axial force as determined by the pressure area metho = Change in pressure area axial force over component l = Young’s Modulus of component = Moment of Inertia = Clearance between the wellbore wall and the work string component

Stretch due to ballooning Stretch due to ballooning is caused by differential pressure inside and outside of the work string, and is defined by the following equation.

∆LBalloon =

[(

−v∗L ∗ ρ s − R 2 ∗ ρ a ∗ L + 2 ∗ Ps − R 2 ∗ Pa 2 E ∗ R −1

(

)

)

(

)]

Where:

∆LBalloon = Change in length due to ballooning mechanism L = Length of work string component element R = Ration of component outside diameter/inside diameter E = Young’s Modulus of component

ν ρs ρa

Landmark

= Poisson’s Ratio of component = Mud density inside work string component = Mud density in annulus at depth of work string component

Ps

= Surface pressure, work string side

Pa

= Surface pressure, annulus side

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243


Tortuosity Wellbore tortuosity is a measure of the random meandering that occur in a well during drilling operations. In designing a well, tortuosity or rippling is not normally modeled during directional well path planning. Typically, a wellpath file is generated based on “ideal” trajectories which follow smooth paths governed by the wellpath calculation method. WELLPLAN uses the minimum curvature method. Similarly, during actual drilling operations, “wiggle” may occur between consecutive stations, even though the actual well path appears to match the “ideal” plan at the station measurement point. The recording of the well’s precise tortuosity can be captured only through the use of closer and closer stations, although this may be impractical. In both the design case and the operational case, the degree of tortuosity is a factor on the overall loading (both torque and drag) on a particular work string. The “smoother” the well, the less the frictional effects. Modelling of wellbore tortuosity has been recognized as especially significant at the planning stage, enabling more realistic load predictions to be established.

Torque Torque is calculated using the following equation.

τ = FN ∗ r ∗ µ ∗

A V

Where:

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T

= Trip speed

A

= Angular speed = diameter ∗ π ∗

V

= Resultant speed =

FN

= Side or normal force

µ r

FD

τ

(T

2

+ A2

)

RPM 60

= Coefficient of friction = Radius of component (for collars the OD of the collar is used for drill pipe, heavy weight and casing, the OD of the tool joint is used for stabilizers the OD of the blade is used) = Drag force = Torque

The side force or normal force is a measurement of the force exerted by the wellbore onto the work string. In the diagram below, the forces acting on a small segment of work string lying in an inclined hole are shown. In this simple diagram, the segment is not moving. From this diagram we can see that the normal force acts in a direction

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245


perpendicular to the inclined surface. The weight of the work string acts downward in the direction of gravity. Another force, the drag force, is also acting on the segment. The drag force always acts in the opposite direction of motion. The segment does not slide down the inclined plane because of the drag force. The magnitude of the drag force depends on the normal force, and the coefficient of friction between the inclined plane and the segment. The coefficient of friction is a means to define the friction between the wellbore wall and the work string.

Where: FN = Normal Force FD = Drag Force W = Weight of segment

Twist Twist in the work string is calculated along the string for each segment, and is accumulated along the length of the work string. Twist is reported as “windup” on the reports.

Θ=

TL JG

Where:

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Θ L T E

= Angle of twist (radians)

G

= M odulus of rigidity =

ν

= Poisson’s ratio

J

= Length of com ponent = Torque (ft-lb) = M odulus of elasticity (psi)

E 2 + 2ν

= Polar m om ent of inertia W here: Pipe:

( 32 (J

J body = π 32 B od − B id J

=π

jo int

4

4 od

− J id

4 4

) )

B od = Body outside diam eter, in B id = Body inside diam eter, in J od = Joint outside diam eter, in J id = Joint inside diam eter, in J =

(J

(.95 J

)

body

∗J

jo int

+ . 05 J body

jo int

)

Collar:

J =

π 32

(B

4 OD

4 − B ID

)

Viscous Drag Viscous drag is additional drag force acting on the work string due to hydraulic effects while tripping or rotating. The fluid forces are determined for “steady” pipe movement, and not for fluid acceleration effects. You can elect to include viscous drag on the Torque Drag Setup Data dialog. The additional force due to viscous drag is calculated as follows. Note that this drag force is added to the drag force calculated in Drag Force Calculations.

∆Force =

Landmark

∆P.π .( Dh2 − D p2 ).D p 4.( Dh − D p ).

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247


There are no direct computations of fluid drag due to pipe rotation. The method shown here derives from the analysis of the Fann Viscometer given in Applied Drilling Engineering. Compute the Shear Rate in the Annulus due to pipe rotation.

SR =

4.π .RPM / 60 D . 1 / D p2 − 1 / Dh2 2 p

(

)

Given the shear rate, the shear stress is computed directly from the viscosity equations for the fluid type. The 479 in the equations below is a conversion from Centipoise to equivalent lb/100 ft2.

Bingham Plastic

τ t = YP + PV .SR / 479 Power Law

τ t = K .SR n / 479

if K is Cp or 4.79 if K is dyn/cm

Herschel Bulkley

τ t = ZG + K .SR n / 479 if K is Cp or 4.79 if K is dyn/cm No consideration is made to laminar or turbulent flow in this derivation. Additionally the combined hydraulic effects of trip movement and rotation are ignored, which would accelerate the onset of turbulent flow. Given the shear stress at the pipe wall (in lb/100ft2), the torque on the pipe is computed from the surface area of the pipe and the torsional radius.

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∆Torque = τ t .2.π .L.( D p / 24) 2 / 100 In the case of rotational torque the forces are equal and opposite between the pipe and the hole, although we are interested in the torque on the pipe and not the reaction from the hole. Where:

Landmark

Dh

= H ole D iam eter (in)

Dh

= P ipe D iam eter (in)

∆P

= A nnular pressure loss calculated according to rheological m odel selected

Vp

= Linear S peed of P ipe (ft/m in)

RPM YP PV ZG

= = = =

R otational S peed of P ipe (rev olutions/m in) Y ield P oint (lbs/100ft2) P lastic V iscosity (cp) Z ero G el Y ield (lbs/100ft2)

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249


References General “The Neutral Zones in Drill Pipe and Casing and Their Significance in Relation to Buckling and Collapse”, Klinkenberg, A., Royal Dutch Shell Group, South Western Division of Production, Beaumont, Texas, March 1951. “Drillstring Design for Directional Wells, Corbett, K.T., and Dawson, R., IADC Drilling Technology Conference, Dallas, March 1984. “Uses and Limitations of Drillstring Tension and Torque Model to Monitor Hole Conditions”, Brett, J.F., Bechett, A.D., Holt, C.A., and Smith, D.L., SPE 16664. “Developing a Platform Strategy and Predicting Torque Losses for Modelled Directional Wells in the Amauligak Field of the Beaufort Sea, Canada”, Lesso Jr., W.G., Mullens, E., and Daudey, J., SPE 19550.

Bending Stress Magnification Factor “Bending Stress Magnification in Constant Curvature Doglegs With Impact on Drillstring and Casing”, Paslay, P.R., and Cernocky, E.P., SPE 22547.

Buckling “A Buckling Criterion for Constant Curvature Wellbores”, Mitchell, R., Landmark Graphics, SPE 52901. “A Study of the Buckling of Rotary Drilling Strings, Lubinski, A., API Drilling and Production Practice, 1950. “Drillpipe Buckling in Inclined Holes”, Dawson,R., and Paslay, P.R., SPE 11167, September 1982. “Buckling Behavior of Well Tubing: The Packer Effect, by Mitchell, R.F., SPE Journal, October 1982.

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“Frictional Forces in Helical Buckling of Tubing”, Mitchell, R.F., SPE 13064. “New Design Considerations for Tubing and Casing Buckling in Inclined Wells”, Cheatham, J.B., and Chen, Y.C., OTC 5826, May 1988. “Tubing and Casing Buckling in Horizontal Wells”, Chen, Y.C., Lin, Y.H., and Cheatham, J.B., JPT, February 1989. “Buckling of Pipe and Tubing Constrained Inside Inclined Wells”, Chen, Y.C., Adnan, S., OTC 7323. “Effects of Well Deviation on Helical Buckling”, Mitchell, R.F., SPE Drilling & Completions, SPE 29462, March 1997. “Buckling Analysis in Deviated Wells: A Practical Method,” SPE Drilling & Completions, SPE 36761, March 1999.

Fatigue “Deformation and Fracture Mechanics of Engineering Materials”, by Richard W.Herzberg, 3rd Edition 1989, Wiley.

Sheave Friction “The Determination of True Hook and Line Tension Under Dynamic Conditions”, by Luke & Juvkam-Wold, IADC/SPE 23859. “Analysis Improves Accuracy of Weight Indicator Reading”, by Dangerfield, Oil and Gas Journal, August 10, 1987.

Side Force Calculations “Torque and Drag in Directional Wells – Prediction and Measurement”, Johancsik, C.A., Friesen, D.B., and Dawson, Rapier, Journal of Petroleum Technology, June 1984, pages 987-992. “Drilling and Completing Horizontal Wells With Coiled Tubing”, Wu, Jiang, and Juvkam-Wold, H.C., SPE 26336.

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Stiff String Model “Background to Buckling”, Brown & Poulson, University of Swansea, Section 3.4 Analysis of Elastic Rigid Jointed Frameworks (with sway). “Engineering Formulas”, Gieck, Kurt, Fourth Ed. McGraw Hill 1983, Section P13, Deflection of Beams in Bending.

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Chapter 7

Hydraulics Analysis Overview Hydraulics can be used to simulate the dynamic pressure losses in the rig’s circulating system, and to provide analytical tools to optimize hydraulics. In this chapter, you will become familiar with using the Hydraulics module and with interpreting analysis results. To reinforce what you learn in the class lecture, you will complete several exercises designed to prepare you for using the module outside of class. The information in this chapter can be used not only as a study guide during the course, but also be used as a reference for future analysis. At the end of this chapter you will find the methodology used for each analysis mode. The methodology is useful for understanding data requirements and analysis results, as well as the theory used as the basis for the analysis. Supporting calculations and references for additional reading are also included in this chapter. In this section of the course, you will become familiar with all aspects of using the Hydraulics module, including: Available analysis modes Defining operating parameters Optimizing Bit Hydraulics Determining the Minimum Flow Rate Determining the Maximum Flow Rate Determining the Bit Nozzle Sizes to Achieve Flow Rate

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Workflow Open a Case using the Well Explorer. Define the hole section geometry. (Case > Hole Section Editor) Define the workstring. Use the same dialog to define all workstrings (drillstrings, tubing, liners, and so forth). (Case > String) Enter wellpath (survey) data. (Case > Wellpath > Editor) Define the fluid used. (Case > Fluid Editor) Specify formation temperatures. (Case > Geothermal Gradient) Optional Step: Specify the eccentricity ratio of the annuli at different measured depths. Eccentricity reduces the pressure drop for annular flow. This information is useful for evaluating the effects of eccentricity on a vertical well. For a deviated well, the pipe is automatically assumed to be fully eccentric in the deviated sections. (Case > Eccentricity) Specify the circulating system configuration. (Case > Circulating System) Define the pore pressure gradients. (Not required for all analysis modes.) (Case > Pore Pressure) Define the fracture gradients. (Not required for all analysis modes.) (Case > Fracture Gradient) Determine bit total flow area for optimized hydraulics. • Access the Graphical Analysis mode. (Select Graphical Analysis from the Mode drop-down list.) • Optional: Specify placement and frequency of standoff devices. (Parameter > Standoff Devices) • Specify the pump limits. (Parameter > Pump Limits) • Determine the optimal bit nozzle total flow area for the optimization method of your choice. (View > Plot)

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Determine the minimum flow rate required to clean the wellbore. • Access the operational hole cleaning model. (Select Hole Cleaning - Operational from the Mode drop-down list.) • Enter operational and cuttings data. (Parameter > Transport Analysis Data) • Determine the minimum flow rate that will clean the hole. (View > Plot > Operational) Determine the maximum flow rate. • Access the Annular Velocity Analysis mode. (Select Annular Velocity Analysis from the Mode drop-down list.) • Optional: Specify placement and frequency of standoff devices. (Parameter > Standoff Devices) • Enter operational data. (Parameter > Rates) • Determine the maximum flow rate that will not result in turbulent annular flow. (View > Plot > Annular Pump Rate) Determine the bit nozzle sizes. • Access the Pressure: Pump Rate Range analysis mode. (Select Pressure: Pump Rate Range from the Mode drop-down list.) • Optional: Specify placement and frequency of standoff devices. (Parameter > Standoff Devices) • Enter the minimum and maximum flow rates you determined in the previous steps. (Parameter > Rates) • Optional: Specify up to five depths you want ECD calculated at. (Parameter > ECD Depths) • Analyze bit hydraulics for the range of flow rates and specified bit nozzle sizes. (View > Report > Pressure Loss) This step may need to be repeated until the bit nozzle configuration is optimized. Determine the tripping schedule that will not exceed a specific pressure change while tripping the work string. (Select Swab/Surge Tripping Schedule from the Mode drop-down list.)

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Calculate pressures and ECD occurring while tripping. (Select Swab/Surge Pressure and ECD from the Mode drop-down list.) Fine tune hydraulics. (Select Pressure: Pump Rate Fixed from the Mode drop-down list.)

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Introducing Hydraulic Analysis When analyzing fluid hydraulics for a wellbore section, there are two fundamental issues to investigate: hole cleaning and rate of penetration. Hole cleaning is usually directly related to the flow rate and drilling fluid properties. Rate of penetration is usually directly related to the bit nozzle sizes. PDC bits are an exception where a specific flow rate is required for acceptable rate of penetration, rather than hydraulic horsepower. Because these drilling hydraulic parameters are interrelated and affect each other, designing hydraulics can be very complicated. The WELLPLAN Hydraulics module is designed to assist the engineer with the complicated issue of designing hydraulics. The module can be used to optimize bit hydraulics, determine the minimum flow rate for hole cleaning, determine the maximum flow rate to avoid turbulent flow, analyze hydraulics for surge and/or swab pressures and to quickly evaluate rig operational hydraulics. The module provides several rheological models, including Bingham Plastic, Power Law, Newtonian, and Herschel Bulkley. The chosen rheological model provides the basis for the pressure loss calculations. Refer to “Herschel Bulkley Model” on page 332, “Power Law Model” on page 332, or “Bingham Plastic Model” on page 331 for more information.

Starting Hydraulics Analysis There are two ways to begin the Hydraulics Module:

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You can select Hydraulics from the Modules Menu, and then select the desired analysis mode.

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You can also click the Hydraulics Button and then select the appropriate desired mode from the drop down list.

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Choose Hydraulics Analysis from Module menu, or by clicking the Hydraulics Module button.

Select desired Hydraulic Analysis mode from submenu, or from Mode drop-down list.

Available Analysis Modes

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Pressure: Pump Rate Range: Calculate pressure losses for each section in the workstring, annulus, the surface equipment and bit, and ECDs for a specified range of flow rates. Refer to “Pressure Loss Analysis Calculations” on page 324 for more information.

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Pressure: Pump Rate Fixed: Calculate pressure losses for each section in the workstring, annulus, the surface equipment and bit for one pump rate. Refer to “Pressure Loss Analysis Calculations” on page 324 for more information.

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Annular Velocity Analysis: Calculate annular velocities at specified flow rates and the critical flow rates for each section in the work string.

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Swab/Surge Tripping Schedule: Calculate a tripping schedule that will not exceed a specified pressure change while moving the work string in or out of the hole. Refer to “Swab/Surge Calculations” on page 327 for more information.

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Swab/Surge Pressure and ECD: Calculate the actual pressure and ECD that occurs when the work string is tripped in or out of the hole. Refer to “Swab/Surge Calculations” on page 327 for more information.

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Graphical Analysis: Examine the effects of changing flow rate and TFA on a number of hydraulics parameters.

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Optimization Planning: Calculate the flow rate and nozzle configuration to optimize bit hydraulics based on several common criteria. Refer to “Optimization Planning Calculations” on page 315 for more information.

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Optimization Well Site: Determine nozzle configuration for optimal hydraulics using recorded rig circulating pressures. These calculations use Scott’s method, and only data specified on the input dialog are used in the calculations. Refer to “Optimization Well Site Calculations” on page 316 for more information.

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Weight Up: Calculate the amount of weight up or dilution material required to adjust mud weight to a specific value. Refer to “Weight Up Calculations” on page 330 for more information.

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Hole Cleaning Operational: Determine the cutting concentration percentage, bed height, and critical transport velocity flow rate in the wellbore using the current string, hole section, fluid and survey. Refer to “Hole Cleaning Methodology and Calculations” on page 307 for more information.

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Hole Cleaning Parametric: Determine the cuttings concentration percentage, bed height, and critical transport velocity flow rate for a range of pump rates for all inclinations from 0 to 90 degrees (in five degree increments). This mode uses data specified on the input dialog, and does not use the current string, hole section, or survey. Refer to “Hole Cleaning Methodology and Calculations” on page 307 for more information.

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Optimizing Bit Hydraulics Using the Graphical Analysis mode, you can determine the optimum flow rate and TFA resulting from specified criteria by examining a series of available graphs. The range of flow rates over which to perform the analysis begins at a very low flow rate and is limited on the high end by the specified pump limits. Bit TFA (total flow area) is determined by using a calculated pressure loss at the bit and the flow rate. The impact force, nozzle velocity, and the hydraulic horsepower at the bit are calculated once the TFA, pressure loss at the bit, and the flow rate are determined. Refer to “Optimization Planning Calculations” on page 315 for more information.

Using Graphical Analysis Mode

Select Graphical Analysis from drop down list.

Entering Pump Specifications Enter data in the Parameter > Pump Limits dialog box to specify the pump constraints that is used as a basis for the Graphical Analysis. The Maximum Pump Pressure is the total system pressure loss. This pressure loss will be used to determine the flow rate based on the pressure loss calculations that pertain to the rheological model you have selected. Refer to “Pressure Loss Analysis Calculations” on page 324 for more information. The Maximum Pump Power establishes a boundary condition that will be displayed as a line on the graphical output from this analysis. Click the Default from Pump Data button to use the Maximum Pump Pressure, and Maximum Pump Power calculated from the information entered on the Circulating System, Mud Pumps tab. Refer to the “Pump

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Power Calculations” on page 325 for more information. The Default from Pump Data button is available when you have specified a surface equipment configuration on the Circulating System > Surface Equipment tab and indicated at least one active pump on the Circulating System > Mud Pumps tab.

Click Default from Pump Data button to default from active pumps listed on Case > Circulating System > Mud Pumps.

Analyzing Results

Analyzing Results Using Plots All Graphical Analysis results are displayed in plots.

Using the Velocity @ Bit Plot Use the View > Plot > Velocity @ Bit plot to determine the velocity of the fluid through the bit for a range of flow rates and varied total flow area (TFA). The following steps can be used to determine the TFA for a specified flow rate or vice versa. 1. Look at the plot and determine the pump rate (x axis) and corresponding TFA (right side Y axis). Keep in mind the pump rate your pump(s) can produce. 2. Determine the velocity (left side Y axis) that corresponds to the pump rate and TFA determined in Step 1. The pump rate begins at zero and increases until the flow rate results in parasitic pressure losses equal to 100% of the total system pressure loss. (Essentially this case results in zero pressure loss at the bit.) The bit velocity is calculated by first determining the pressure loss through the bit. Pressure loss calculations are based on the rheological model selected on the Case > Fluid Editor and assumes the total system pressure loss is equal to the maximum pump pressure entered on the Parameter > Pump Limits dialog. Based on the total system pressure

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loss, as well as the workstring, fluid, and hole section information entered into the Case > String Editor, Case > Fluid Editor, and Case > Hole Section Editor, we can determine the pressure loss at the bit. Knowing the pressure loss at the bit, the flow rate and TFA can be calculated. The velocity at the bit can be determined.

This plot is used to determine the bit velocity and required flow rate or TFA given a flow rate or TFA.

Using the Power Per Area Plot Use the View > Plot > Power Per Area plot to determine the power per area through the bit for a range of flow rates and varied total flow area (TFA). The following steps can be used to determine the TFA, and pump rate required to maximize bit power per area. 1. Look at the plot and determine the pump rate (x axis) corresponding to the TFA in the legend. 2. Determine the Power/Area (right side Y axis) that corresponds to the pump rate determined in Step 1. If the pumps you are using are not capable of producing this pump rate, use the maximum pump rate the pumps can produce. The pump rate begins at zero and increases until the flow rate results in parasitic pressure losses equal to 100% of the total system pressure loss. (Essentially this case results in zero pressure loss at the bit.) The power per area is calculated by first determining the pressure loss through the bit. Pressure loss calculations are based on the rheological Landmark

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model selected on the Case > Fluid Editor, and assume the total system pressure loss is equal to the maximum pump pressure entered on the Pump Limits dialog. Based on the total system pressure loss, as well as the workstring, fluid, and wellbore information entered into the Case > String Editor, Case > Fluid Editor, and Case > Hole Section Editor, we can determine the pressure loss at the bit. Knowing the pressure loss at the bit and the flow rate, the TFA can be calculated. From this, the power per area of the bit can be determined.

Read maximum power per area and corresponding pump rate from plot.

Read the TFA for the maximum power/area in the legend. Using this TFA, read the pump rate. Use this pump rate to read the power/area.

Using the Impact Force Plot Use the View > Plot > Impact Force plot to determine the impact force of the fluid through the bit for a range of flow rates and varied total flow area (TFA). The following steps can be used to determine the TFA and pump rate required to maximize the impact force at the bit.

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1. Look at the plot and determine the pump rate (x axis) corresponding to the TFA in the legend. (This TFA is the TFA to maximize impact force.) 2. Determine the impact force (right side Y axis) that corresponds to the pump rate determined in Step 1. If the pumps you are using are not capable of producing this pump rate, use the maximum pump rate the pumps can produce. The pump rate begins at zero and increases until the flow rate results in parasitic pressure losses equal to 100% of the total system pressure loss. (Essentially this case results in zero pressure loss at the bit.) The impact force is calculated by first determining the pressure loss through the bit. Pressure loss calculations are based on the rheological model selected on the Case > Fluid Editor and assume the total system pressure loss is equal to the maximum pump pressure entered on the Pump Limits dialog. Based on the total system pressure loss, as well as the workstring, fluid, and wellbore information entered into the Case > String Editor, Case > Fluid Editor, and Case > Hole Section Editor, we can determine the pressure loss at the bit. Knowing the pressure loss at the bit and the flow rate, the TFA can be calculated. From this, the impact force at the bit can be determined.

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Read maximum impact force and corresponding pump rate from plot using the TFA in the legend.

Read the TFA for the maximum impact force in the legend. Using this TFA, read the pump rate.

Using the Power Plot Use the View > Plot > Power plot to determine the power of the fluid through the bit for a range of flow rates and varied total flow area (TFA). The following steps can be used to determine the TFA and pump rate required to maximize power at the bit. 1. Look at the plot and determine the pump rate (x axis) corresponding to the TFA in the legend. 2. Determine the Power (right side Y axis) that corresponds to the pump rate determined in Step 1. If the pumps you are using are not capable of producing this pump rate, use the maximum pump rate the pumps can produce. The pump rate begins at zero and increases until the flow rate results in parasitic pressure losses equal to 100% of the total system pressure loss. (Essentially this case results in zero pressure loss at the bit.)

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The power at the bit is calculated by first determining the pressure loss through the bit. Pressure loss calculations are based on the rheological model selected on the Case > Fluid Editor and assume the total system pressure loss is equal to the maximum pump pressure entered on the Parameter > Pump Limits dialog. Based on the total system pressure loss, as well as the workstring, fluid, and wellbore information entered into the String Editor, Fluid Editor, and Hole Section Editor, we can determine the pressure loss at the bit. Knowing the pressure loss at the bit and the flow rate, the TFA can be calculated. Knowing the flow rate and TFA, the power at the bit can be determined.

For any given flow rate, the parasitic pressure loss plus the bit pressure loss is equal to total system pressure loss.

Using the TFA in the legend, read the flow rate. Use this flow rate to determine the maximum bit power.

Using the Pressure Loss Plot Use the View > Plot > Pressure Loss plot to determine the pressure loss through the bit for a range of flow rates and varied total flow area (TFA). The following steps can be used to determine the TFA as well as the pump rate required to achieve a certain pressure loss at the bit. 1. Look at the plot and determine the pump rate (x axis) corresponding to the desired pressure loss at the bit (left side Y axis). 2. Determine the TFA (right side Y axis) that corresponds to the pump rate determined in Step 1.

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The pump rate begins at zero and increases until the flow rate results in parasitic pressure losses equal to 100% of the total system pressure loss. (Essentially this case results in zero pressure loss at the bit.) On this particular plot, the combined pressure loss through the bit plus the parasitic pressure loss should equal the total system pressure loss. The first step in this analysis is determining the pressure loss through the bit. Pressure loss calculations are based on the rheological model selected on the Case > Fluid Editor, and assume the total system pressure loss is equal to the maximum pump pressure entered on the Case > Pump Limits dialog. Based on the total system pressure loss, as well as the workstring, fluid, and hole section information entered into the Case > String Editor, Case > Fluid Editor, and Case > Hole Section Editor, we can determine the pressure loss at the bit. Knowing the pressure loss at the bit and the flow rate, the TFA can be calculated.

For any flow rate the parasitic pressure loss plus bit pressure losses equal the total system pressure loss.

Using the desired bit pressure loss, read the required flow rate and TFA- or use the TFA and read the required flow rate and pressure loss.

Using the Power vs. Impact Force Plot Use the View > Plot > Power vs Impact Force plot to determine the maximum impact force, or bit power per area for a range of flow rates. 1. Look at the plot and determine the pump rate (X axis) corresponding to the maximum impact force, or bit power per area. 2. Read the corresponding impact force or bit power per area from the other curve on the plot.

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The pump rate begins at zero and increases until the flow rate results in parasitic pressure losses equal to 100% of the total system pressure loss. (Essentially this case results in zero pressure loss at the bit.) The first step in this analysis is determining the pressure loss through the bit. Pressure loss calculations are based on the rheological model selected on the Case > Fluid Editor and assume the total system pressure loss is equal to the maximum pump pressure entered on the Pump Limits dialog. Based on the total system pressure loss, as well as the workstring, fluid, and hole section information entered into the Case > String Editor, Case > Fluid Editor, and Case > Hole Section Editor, we can determine the pressure loss at the bit. Knowing the pressure loss at the bit and the flow rate, the TFA can be calculated. Knowing the flow rate and TFA, the impact force or bit power per are can be calculated.

Read maximum bit power/area and corresponding impact force and pump rate.

Read maximum impact force and corresponding bit power/area and pump rate.

Numerical Optimization This analysis mode is used for determining the flow rate and nozzle configuration so you can achieve optimization with respect to one of the following methods: z

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Maximum bit jet impact force

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Maximum nozzle velocity

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Percent system pressure loss at the bit

This method is one of three analysis modes used by the Hydraulics module for optimizing hydraulics. Graphical Analysis and Optimization Well Site are the other two methods. The flow rate and nozzles are calculated to fully use the available pump pressure. Pump pressure is considered to be the sum of parasitic losses (losses in the workstring, annulus, and surface lines) and the pressure drop over the bit, and it is equal to the maximum pump pressure. After the true optimum flow rate is determined, it can be increased slightly to use all available pump pressure. You can specify a minimum annular velocity to serve as a lower boundary for the flow rate. At no point in the annulus will the flow rate be lower than the specified minimum flow rate. The minimum annular velocity will occur in the widest annulus section. Imposing this rule on the optimization may result in a flow rate that does not generate the optimum bit hydraulics. You can also specify that turbulence in the annulus is not allowed, which will put a limit on the maximum flow rate. Specifying that turbulence is not allowed always limits the calculated flow rate, even if the flow rate is less than the true optimum or if it forces a velocity that is less than the specified minimum annular velocity. Imposing this rule on the optimization may result in a flow rate that does not generate the optimum bit hydraulics. The calculation determines the nozzle sizes based on the number of nozzles specified that will as closely as possible provide the required TFA. You can restrict the freedom in nozzle selection by specifying a non-zero value for minimum nozzle size, or by specifying another number of nozzles. The final TFA may not be the exact optimal TFA after the nozzle configuration is determined. As discussed earlier, the result of the calculations (flow rate and nozzles) may not necessarily match the optimum solution, but may be restricted by the imposed limitations. To remove all restrictions that you can control, you can specify the following in the Solution Constraints dialog. z

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Mark the Allow Turbulence in the Annulus check box.

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Specify zero in the Minimum Annular Velocity field.

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Specify zero in the Minimum Nozzle Size field.

You can view a brief numerical summary of the optimization results for each optimization method by looking in the Quick Look group box on the Solution Constraints dialog (This is the same dialog that you entered data pertinent to the analysis.). This information is presented in a tabular format. For each optimization method, the optimal flow rate, nozzle configuration, and TFA is presented.

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Determining the Minimum Flow Rate The minimum flow rate is the rate that will clean the wellbore for a specified rate of penetration, rotary speed, pump rate, bed porosity, cuttings diameter, and size. The Hydraulics module offers two hole cleaning analysis modes. These modes are Hole Cleaning-Parametric and Hole Cleaning-Operational. Although both modes are based on the same theory, the results and usage of the modes are different. You should use the Hole CleaningOperational analysis first to analyze your current Case. After performing the Operational analysis, you may want to study the effects of varying parameters using the Hole Cleaning-Parametric analysis mode. The operational analysis determines the percentage of cuttings in the annulus of the current active case. The cuttings concentration percentage, bed height, and minimum flow rate to avoid bed formation is determined from the current inclination, annular diameters, and other Case data. Information entered on the Case > Fluid Editor, Case > String Editor, Case > Wellpath Editor, and Case > Hole Section Editor will be used to calculate annular volumes and hole inclination.

Starting the Hole Cleaning Operational Analysis

Select Hole Cleaning Operational from the drop down list.

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Entering Analysis Data The Parameter > Transport Analysis Data dialog is used to specify the analysis parameters that will be used in the Hole CleaningOperational analysis.

Normal range is 0.1 to .25 inches. A typical estimate of the porosity of the cuttings bed is 36%.

Enter the specific gravity of the formation being drilled.

Analyzing Results Analyzing Results Using Plots

Using the Operational Plot The View > Plot > Operational plot presents the following for each measured depth in the wellbore: • • • •

Inclination Minimum flow rate to avoid cuttings formation Suspended cuttings volume Bed height

The bed height and cuttings volume portions of the plot are calculated using the flow rate specified on the Parameter > Transport Analysis Data dialog (Operational). The minimum flow rate, and inclinations portions of the plot are independent of the specified flow rate. If there is a bed height forming, the total cuttings volume will begin to become greater than the suspended cuttings volume in that portion of the

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wellbore. Also, you will notice that the bed height begins to form when the minimum flow rate to avoid bed formation for a section of the well is greater than the flow rate specified on the Transport Analysis Data dialog (Operational). In order to avoid the formation of a cuttings bed in that portion of the well, you must increase the specified flow rate to a rate greater than the minimum flow rate to avoid bed formation. Use the Rate of Penetration slider control to specify the rate at which the formation is being drilled. This value is used to determine the amount of cuttings produced per time increment — in effect a cuttings flow rate. When you specify a value here it has the same effect as specifying a value in the Rate of Penetration field in the Parameter > Transport Analysis Data dialog. The new value you specify with the slider will appear in the Rate of Penetration field the next time you open the Transport Data dialog. This analysis uses the data input on the Fluid Editor, String Editor, Wellpath Editor, Hole Section Editor and the Transport Analysis (Operational) Data dialog.

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Read each plot using the same Y axis.

Rate of Penetration slider can be used to change the ROP and immediately view the results in the plots. The ROP used in the plots is specified here.

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Pump Rate slider can be used to change the pump rate and immediately view the results in the plots. The rate used in the plots is specified here.

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Analyzing Results Using the Operational Report

Configuring Report Options The View > Report Options dialog is used to specify additional information to include on the report. Using this dialog, you can include or exclude much of the information defining the case you are analyzing.

Check boxes to include desired information on the report.

Using the Operational Report The View > Report > Operational report is a representation, in table form, of the information available on the View > Plot > Operational plot, as well as some additional information. From the report, you can determine the minimum pump rate (flow rate when a cuttings bed will begin to form). For the flow rate specified on the Parameter > Transport Analysis Data dialog (Operational), you can also determine the cuttings volume, bed height, and equivalent mud weight over the entire wellbore using the MD Calculation Interval you specify on the Transport Analysis Data dialog (Operational).

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Determining the Maximum Flow Rate Annular Velocity can be used to determine the flow regime and critical velocity for each section in the annulus for a range of flow rates. Critical velocity is the velocity resulting from the critical flow rate. For the Power Law and Bingham Plastic rheology models, the critical flow rate is the flow rate required to produce a Reynold’s number greater than the critical Reynold’s number for laminar flow. The Reynold’s number is dependent on mud properties, the velocity the mud is traveling, and on the effective diameter of the work string or annulus the mud is flowing through. Based on the calculated Reynold’s number and the rheological model you are using, it is possible to determine the flow regime of the mud. For regimes where the Reynold’s number lies between the critical values for laminar and turbulent flow, a state of transitional flow exists. For the Herschel Bulkley rheology model the critical flow rate is the flow rate required to exceed the Ga number corresponding to laminar flow. The Ga number is dependent on mud properties, the velocity the mud is traveling, and on the effective diameter of the work string, or annulus the mud is flowing through. Based on the calculated Ga number and the rheological model you are using, it is possible to determine the flow regime of the mud. For regimes where the Ga number lies between the critical values for laminar and turbulent flow, a state of transitional flow exists.

Starting Annular Velocity Analysis Mode

Select Annular Velocity from drop down list.

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Defining Pump Rates Use the Parameter > Rates dialog to enter the range of flow rates to analyze.

When specifying the range and increment, keep in mind that up to 15 flow rates can be analyzed at a time.

Analyzing Results The analysis results are available using the View Menu.

Analyzing Results Using Plots

Using the Annular Velocity Plot Use the View > Plot > Annular Velocity plot to determine the velocity of the fluid in the annulus for any measured depth in the wellbore for the range of flow rates you specified on the Parameter > Rates dialog. This graphical analysis calculates the annular velocity across each annulus section and compares the profile with the critical velocity. Note that when an annular velocity curve crosses the critical velocity curve, then the flow regime for that annulus section moves from laminar to either transitional or turbulent flow. The fluid velocity is calculated based on the rheological model selected on the Case > Fluid Editor. Cross-sectional flow areas are determined from information input on the Case > String Editor and the Case > Hole Section Editor.

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Annular Velocity vs Measured Depth for each flow rate analyzed

Annular velocity exceeding laminar flow

Using the Annular Pump Rate Plot Use the View > Plot > Annular Pump Rate plot to determine the pump rate that causes fluid flow outside of the laminar flow regime for any depth in the wellbore. Pump rates greater than the critical flow rate curve at any depth indicate that the flow regime moves out of laminar flow and into transitional or turbulent flow. The plot does not distinguish transitional from turbulent flow. The calculations are based on the rheological model selected on the Case > Fluid Editor. Cross-sectional flow areas are determined from information input on the Case > String Editor and the Case > Hole Section Editor.

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Pump rates (at a given measured depth) greater than the Critical Pump Rate will result in transitional or turbulent flow.

Analyzing Results Using Tables

Using the Annulus Information Table Use the View > Table > Annulus Information table to view pressure losses, and critical flow rates for a range of specified flow rates. You can use this table to determine the flow regime, critical pump rate, annular velocity, and pressure loss for all annular cross-sectional areas. This table presents information calculated based on the range of flow rates specified on the Parameter > Rates dialog, Case > Fluid Editor, Case > String Editor, Case > Wellpath > Editor and the Case > Hole Section Editor.

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Flow rates are specified on the Rates dialog.

Pressure Loss, Average Velocity and Reynolds number are calculated using the rheology model specified on Fluid Editor.

Flow regimes can be turbulent, laminar, or transition.

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Determining the Bit Nozzle Sizes You have determined the minimum and maximum flow rates as well as an idea of the bit total flow area you would need to optimize bit hydraulics. The next step is to determine the actual bit nozzle sizes to achieve the most efficient bit hydraulics yet still maintain the flow rate within the minimum and maximum rates you determined.

Starting the Pressure: Pump Rate Range Analysis Mode

Select desired mode from drop down list.

Defining the Pump Rate Range The Parameter > Rates dialog is used to specify pump information to calculate system pressures losses for a range of pump rates. The range of pump rates is determined by the Minimum, Maximum, and Increment Pump Rate specified in the Pump Rate section of the dialog. The Minimum Pump Rate specifies where the pressure loss analysis calculations begins. This rate will be increased by the Increment Pump Rate until the Maximum Pump Rate is reached or five rates (including the Minimum and Maximum Rates) have been analyzed. In the Pumping Constraints control group of the dialog, enter the maximum pump discharge pressure of which the pump is capable. If you are using more than one pump, enter the minimum of all active pump’s maximum pump pressures. You must also enter the Maximum Pump Power the pump can produce. Refer to the “Pump Power Calculations” on page 325 for more information. Press the Default from Pump Data button to use the Maximum Pump Pressure, and Maximum Pump Power calculated from the information

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entered on the Circulating System > Mud Pumps tab. Refer to the “Pump Pressure Calculations” on page 326 for more information. The Default from Pump Data button is available when you have specified a surface equipment configuration on the Circulating System > Surface Equipment tab, and indicated at least one active pump on the Circulating System > Mud Pumps tab. Check the Include Tool Joint Pressure Losses box to include tool joint pressure losses in the calculations. Tool joint pressure losses are sometimes referred to as minor pressure losses. Pressure losses due to tool joint upset in the annulus are accounted for in the calculations by considering the cross-sectional area change in the annulus regardless of whether or not this box is checked. However, in these calculations the length of the tool joint is not considered. Refer to “Tool Joint Pressure Loss Calculations” on page 329 for more information. Check the Use String Editor box to use the nozzle configuration entered for the bit component on the Case > String Editor. Click the Nozzles button to gain access to the Nozzles dialog. On the Nozzles dialog, you may view the nozzle configuration currently on the Case > String Editor or you may enter a different nozzle configuration for use in this analysis

Specify the range of pump rates to analyze.

Enter pump data.

Check box to include tool joint pressure losses Mark this check box to update the fluid rheology using the formation temperature defined in the Geothermal Gradient dialog.

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Check box to use String Editor nozzles, or click the Nozzles button to use other nozzles.

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Roughness affects friction pressure losses in turbulent flow only. The nominal value of surface roughness for new steel pipe is 0.0018 inches. Old or corroded pipe can have values up to .0072 inches. This factor is more important in deep wells using old tubulars.

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Specifying the Nozzle Configuration The Nozzles dialog is accessible via the Nozzles button. The Nozzles dialog consists of two tabs. One tab displays the current nozzle configuration specified on the Case > String Editor, and the other tab allows specification of different nozzle configurations for analysis. If a tested nozzle configuration results are favorable, you may copy this configuration to the bit specified in the String Editor.

Four nozzles sizes can be specified and the Total Flow Area will be calculated.

Specify the Total Flow Area if you want to use a certain TFA rather than nozzles sizes.

The Local tab can be used to specify any nozzle configuration you want to analyze. If you determine this configuration is optimal, then you may copy the nozzle configuration to the String Editor. The advantage to changing the nozzles using this tab rather than the String Tab is that the String Editor nozzles will not be altered unless you click the Copy to String button.

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Four nozzles sizes can be specified and the Total Flow Area will be calculated.

Specify the Total Flow Area if you want to use a certain TFA rather than nozzles sizes. Click Copy to String to copy nozzles to String Editor.

Specifying Depths to Calculated ECD On the Parameter > ECD Depths dialog, enter up to five measured depths you would like ECD (equivalent circulating density) calculated. ECD may be calculated at any depth. Commonly ECD is calculated at the last casing shoe. The ECD of the mud is the mud weight that would exert the circulating pressures under static conditions at the specified depth.

Enter up to five depths to calculated ECD.

Analyzing Results Results for the Pressure: Pump Rate Range analysis are presented in a plot and a report. All results are available using the View Menu.

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Using the Pressure Loss Plot The View > Plot > Pressure Loss plot displays the system pressure loss, as well as bit, string and annulus pressure losses for the range of flow rates specified on the Parameter > Rates dialog. Each curve on the graph represents one type of pressure loss. Pressure loss calculation are based on the rheological selected on the Case > Fluid Editor. Annular volumes are calculated based on information entered on the Case > String Editor and the Case > Hole Section Editor.

Maximum pump pressure is indicated on plot. The maximum pump pressure is input on the Case > Circulating System > Mud Pumps tab.

Separate curves for bit, string, annulus, and system pressure losses

Check these boxes to include the effects of tool joint pressure losses and/or mud temperature effects. You can also indicate if you want to include these effects and pressure losses by checking the appropriate boxes on the Parameter > Rates dialog.

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Using the Pressure Loss Report

Configuring Report Options The View > Report Options dialog is used to specify what additional information to include on the report. Using this dialog, you can include or exclude much of the information defining the case you are analyzing.

Check boxes to include desired information on the report.

The View > Report > Pressure Loss report will sum the total pressure loss and the hydraulic power across each work string section, both inside the string and in the annulus. For example, inside the work string the total pressure loss across the entire drill pipe section is calculated, then across the HWDP section, then the drill collar section. Similarly, in the annulus, it calculates the pressure drop across the entire drill pipe section, the HWDP section and so forth. The pressure losses through the surface equipment are shown along with the total system pressure loss at the specified flow rate. Finally, the report splits the annulus into separate sections based on a change in either the wellbore effective diameter and/or a change in the outside diameter of the work string. For each annular section, the report displays the following information: • • • • • • •

Hole OD Pipe OD Pressure loss Average velocity Reynolds number Critical flow rate Flow regime (laminar, transitional, or turbulent)

This information is presented for each of the flow rates you specify on the Parameter > Rates dialog.

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Fine Tuning Hydraulics The pressures in the circulating system will be calculated at the flow rate specified on the Rate Dialog using the rheological model selected on the Fluid Editor. You can analyze the pressure (dynamic and static pressures combined) at any depth from surface to TD in the work string, annulus or at the bit. The static pressure losses are those due to the hydrostatic pressure of the mud. The dynamic pressure losses are the frictional pressure losses that occur during circulation of the mud at a specified flow rate. You can analyze these pressure losses in the Pressure Pump Rate Range report also. You can also analyze the ECD (Equivalent Circulating Density) at any depth.

Starting Pressure Pump Rate Fixed Analysis Mode

Select Pump Rate Fixed from drop down list.

Defining the Pump Rate to Analyze Pump Rate is the only input required and is the only flow rate used to calculate the pressure losses. Pressure loss information can be used to optimize hydraulics based on several optimization criteria. A summary of the analysis results is displayed in the Quick Look section of the Parameter > Rate dialog. For more information on the data presented in the Quick Look section, refer to the online help.

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Enter flow rate to analyze.

The Quick Look section displays a summary of the analysis.

Use String Editor nozzles, or specify your own using the Nozzles Button.

Use this slider control to specify the pump rate instead of entering a value in the Pump Rate field located at the top of this dialog. You can specify any value between 1 and 2,500 gpm. The value you define with this control is displayed in the Pump Rate field.

Use this slider to specify the total flow area, rather than use the total flow area of the bit specified on the String Editor Spreadsheet. The slider range is from 0 to 4 square inches of flow area. If the Use String Editor Bit Nozzles box is checked, using this slider will not impact the calculations.

Analyzing Results In addition to the information in the Quick Look section, there are two plots available: • •

Pressure Loss vs. Measured Depth ECD vs. Depth.

These plots are available via the View menu.


Using the Pressure vs. Depth Plot You can use the View > Plot > Pressure vs Depth plot to display the combined (hydrostatic and frictional) pressure losses through the workstring, annulus, or through the bit at any depth in the wellbore.

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However, this graph does not show what portion of the pressure loss is due to static versus dynamic losses. The plot also indicates the casing shoe setting depth, as well as the pore pressure and fracture gradients for all measured depths in the wellbore. The information presented on the plot pertains to the flow rate you specified on the Parameter > Rate dialog. The pressure losses are calculated based on the rheological method specified on the Case > Fluid Editor. The shoe setting depth is retrieved from the Case > Hole Section Editor, and the pore pressure and fracture gradient information is found on the Case > Pore Pressure and Case > Fracture Gradient spreadsheets.

Annular pressure is between the pore and fracture pressures.

Casing shoe Use the slider to change flow rate if you want to analyze another rate. When you specify a value here, it has the same effect as specifying a value in the Pump Rate field in the Rate dialog. The new value you specify with the slider will appear in the Pump Rate field the next time you open the dialog.

Bit pressure loss

Changing the Display of Data on This Plot Right-click anywhere on the plot, and select the alternate view from the right-click menu. You can also display the ECD vs. Depth plot by using View > Plot > ECD vs Depth.

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To display the pressure loss plot versus TVD, or if you want to view the data expressed as ECD rather than pressure, right-click anywhere on the plot and select the alternate view you want to display from the right-click menu.

Using the ECD vs. Depth Plot Use the View > Plot > ECD vs Depth plot to determine the equivalent circulating density (ECD) in the annulus at any measured depth in the wellbore. The plot displays the pore pressure and fracture gradient expressed as a density for all measured depths. The shoe setting measured depth is also be indicated. The ECD is the density that will exert the circulating pressure under static conditions. The pore pressure and fracture gradients are displayed as densities to facilitate comparison. The pressure losses are calculated based on the rheological method specified on the Case > Fluid Editor. The shoe setting depth is retrieved from the Case > Hole Section Editor and the pore pressure and fracture gradient information is found on the Case > Pore Pressure and Case > Fracture Gradient spreadsheets. You can change the way the data is presented on this plot by selecting another view from the right-click menu. Refer to “Changing the Display of Data on This Plot” on page 290.

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ECD in the annulus for the current flow rate.

Pore pressure

Casing shoe

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Calculating a Tripping Schedule The Swab/Surge Tripping Schedule analysis assists with determining the rate to trip in or out of the hole without exceeding a pressure change (Allowable Trip Margin) you specify. The surge or swab pressure changes in the well can be calculated with or without flow through an open-ended workstring or without flow through a closed-ended workstring. You must specify the length of a stand of drill pipe or casing, and the Allowable Trip Margin. The Allowable Trip Margin is the maximum change in ECD at the bit or casing shoe that you are willing to accept. Specifying a large value allows large tripping speeds, whereas a low value only allows low tripping speeds. Moving a work string is accompanied by a displacement of the mud in the hole that can result in pressure changes. Depending on the direction of the string movement, and the resulting mud displacement, these changes may add to the pressure exerted by the mud. If the pipe movement is downward, this may result in a surge pressure. If the pipe movement is upward, this may result in a swab pressure. These pressure changes may impair the stability of the hole through removal of the filter cake or may result in a blowout by dropping below the pore pressure, or may cause lost circulation by exceeding the fracture pressure and fracturing the formation.

Starting Swab/Surge Tripping Schedule Analysis

Select Swab/Surge Tripping Schedule from drop down list.

Defining Analysis Constraints Enter data in the Parameter > Operations Data dialog box to specify the conditions you want to use to calculate a Surge/Swab Tripping Schedule. For both swab and surge analysis, you can use a closed or open ended string by checking the appropriate boxes. You may perform

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an analysis with the end open and closed at the same time. If you are using an open ended string, you may also specify a flow rate. The stand length is used to used to calculate the tripping schedule as time per stand. Check the Use String Editor box to use the nozzle configuration entered for the bit component on the Case > String Editor. Press the Nozzles button to gain access to the Nozzles dialog. On this dialog, you may view the nozzle configuration currently on the Case > String Editor, or you may enter a different nozzle configuration for use in this analysis.

Enter the maximum pressure change that you will allow during tripping out of the hole.

Enter the length of a stand of drillpipe. Use String Editor nozzles, or specify your own using the Nozzles button.

Analyzing Results Using Reports to Analyze Results

Using the Swab/Surge Report The View > Report > Swab/Surge report indicates the minimum allowable trip time per stand of pipe based on an allowable trip margin specified in ppg or psi. Depending on the situation, there could be one value for all stands or there could be a number of values for different sets of stands. If you specify a high value for the allowable trip margin, it is possible that the minimum time per stand (10 seconds) will not reach the

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allowable trip margin. In that case, the trip schedule produced will indicate that all stands can be tripped at the minimum time per stand. Conversely, if you specify a very small value for the allowable trip margin, it is possible that even at the maximum time per stand (200 seconds), the allowable trip margin will still be exceeded. In that case, the trip schedule will show that all stands should be tripped at the maximum time per stand (200 seconds). In order to maintain a .5 ppg trip margin, the stands should be tripped at the time/stand indicated.

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Analyzing Pressures and ECDs While Tripping The Swab/Surge Pressure and ECD analysis assists with determining the pressures and ECD at the bit, casing shoe and bottom of the hole as the pipe is tripped in or out of the hole at speeds ranging from 10 seconds per stand to 200 seconds per stand. The pressure and ECD calculations can be performed with or without flow through an open ended workstring, or without flow through a closed ended workstring. You must specify the length of a stand of drill pipe. Moving a work string causes a displacement of the mud in the hole that can result in pressure changes. Depending on the direction of the string movement, and the resulting mud displacement, these changes may add to the pressure exerted by the mud. If the pipe movement is downward, this may result in a surge pressure. If the pipe movement is upward, this may result in a swab effect. These pressure changes may impair the stability of the hole through removal of the filter cake, or may even result in a blowout by dropping below the pore pressure or may cause lost circulation by exceeding the fracture pressure and fracturing the formation.

Starting Swab/Surge Pressure and ECD Analysis Mode

Select Swab/Surge Pressure and ECD from mode data drop down list.

Defining Operations Constraints Enter data in the Parameter > Operations Data dialog box to specify the conditions you want to use to analyze Surge/Swab Pressures and ECDs. For both swab and surge analysis, you can use a closed or open ended string by checking the appropriate boxes. You may perform an analysis with the end open and closed at the same time. If you are using an open ended string, you may also specify a flow rate. The stand length is used to used to calculate the tripping schedule as time per stand.

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Check the Use String Editor box to use the nozzle configuration entered for the bit component on the String Editor. Press the Nozzles button to gain access to the Nozzles dialog. On this dialog, you may view the nozzle configuration currently on the Case > String Editor or you may enter a different nozzle configuration for use in this analysis.

Check closed if you don’t want fluid flow through the pipe.

Enter the length of a stand of drillpipe. Use String Editor nozzles, or specify your own using the Nozzles Button.

Analyzing Results Using Plots to Analyze Results There are four available plots: • • • •

Swab Open End Swab Closed End Surge Open End Surge Closed End

Use these plots to determine the pressures and ECD (equivalent circulating density) to expect for trip speeds ranging from zero to 200 seconds per stand while tripping in or out. These plots pertain to swabbing or surging with an open or closed ended workstring. If the workstring is open ended, you may specify a flow rate through the string on the Parameter > Operations Data dialog. If you specified a flow rate greater than zero, the calculated pressure and ECD will include the effects of this flow rate. These plots will display the pressure and ECD at the bit, at the casing shoe (as the bit passes the shoe) and at total depth (TD).

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If the bit is at total depth (TD), the curves will overlay, and it may appear that the curves are missing from the plot. The bit depth is obtained from the Case > String Editor, and the stand length is specified on the Operations Data Dialog. The casing shoe depth is retrieved from the Case > Hole Section Editor. You may want to review the Swab/Surge report for additional information.

ECD values read on this scale.

Read pressure on this scale.

Using Reports to Analyze Results

Using the Swab/Surge Report This report indicates the minimum allowable trip time per stand of pipe. Depending on the situation, there could be one value for all stands or there could be a number of values for different sets of stands. If you specify a high value for the allowable trip margin, it is possible that the minimum time per stand (10 seconds) will not reach the allowable trip margin. In that case, the trip schedule produced will indicate that all stands can be tripped at the minimum time per stand. Conversely, if you specify a very small value for the allowable trip margin, it is possible that even at the maximum time per stand (200 seconds), the allowable trip margin will still be exceeded. In that case,

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the trip schedule will show that all stands should be tripped at the maximum time per stand (200 seconds).

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Supporting Information and Calculations The calculations and information contained in this section provide details pertaining to many of the steps previously presented during the descriptions of the analysis mode methodologies. These calculations and information are presented in alphabetical order using the calculation or topic name. If the information in this section does not provide you the detail you require, please refer to “References” on page 331 for additional sources of information pertaining to the topic you are interested in.

Backreaming Rate (Maximum) Calculation   Qcrit | DP  BR max = ROP max  (Qcrit | DP − Qmud )  Where: BR max ROP max Qcrit Qmud DC DP

= Maximum backreaming rate (ft/hr) = Maximum rate of penetration (ft/hr) = Critical flow rate (gpm) = Mud flow rate (gpm) = Drill collar ID (in) = Drill pipe ID (in)

Bingham Plastic Rheology Model Shear Stress – Shear Rate Model

τ = τ y + Kγ

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Average Velocity in Pipe

 4  Q  V p =   2   π  D 

Average Velocity in Annulus

 Q  4   Va =   2 2  π   DH − DP 

Apparent Viscosity for Annulus

PVaa

 DH 2 − DP 2 = PV + 62.674773(YP)(DH − DP ) Q 

   

Apparent Viscosity for Pipe

 D3   PVap = PV + 62.674773(YP)  Q 

Modified Reynolds Number for Annulus  Q Ra = 1895.2796( ρ )(DH − DP )  PV D 2 − D 2 P  aa H

(

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301


Modified Reynolds Number for Pipe

 Q   R p = 1895.2796( ρ )  PV D   ap 

Pressure Loss in Annulus

If Ra > 2000 , then

Pa =

.0012084581(ρ .75 )(PV .25 )(Q1.75 )L

( DH

− DP )

1.25

(D

2 H

− DP

)

2 1.75

If laminar flow, then

  YP Pa = (.053333333)  DH − DP 

  .0008488263(PV )Q  +  2 2 2    (DH − DP ) DH − DP

(

)

  L  

Pressure Loss in Pipe

If R p > 2000 , then

Pp =

.0012084581(ρ .75 )(PV .25 )(Q 1.75 )L D 4.75

If laminar flow, then

  YP   .0008488263(PV )Q  Pp = (.053333333)  +   L D4 D   

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Critical Velocity and Flow in Annulus

(2000 + PVx ) + Rc Vca =

 ρ 2 PV x + 1.066(YPx )  gc ρ 2(DH − DP ) gc

 ( D H − D P )2  2 Rc 

π  2 Qca = Vca  (DH − DP ) 4

Critical Velocity and Flow in Pipe

(2000 + PV x ) + Rc Vca =

 ρ 2 PV x + 1.066 (YPx )  gc 2D

ρ

 D2   2 Rc

gc

π  Qca = Vca   D 2 4 Where:

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D DP DH K Vp

= Pipe inside diameter (ft) = Pipe outside diameter (ft)

Va Vca Vcp

= Average fluid velocity for annulus (ft/sec)

= Annulus diameter (ft)

(

2

= Consistency factor lb ft sec

n

)

= Average fluid velocity for pipe (ft/sec)

= Critical velocity in annulus (ft/sec) = Critical velocity in pipe (ft/sec)

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L = Section length of pipe or annulus (ft) P = Pressure loss in pipe or annulus lb ft 2

(

Q = Fluid flow rate ( ft 3 sec )

)

Qca = Critical flow rate in annulus ( ft 3 sec )

(

Qcp = Critical flow rate in pipe ft 3 sec

γ

= Shear rate (1/sec)

τ

= Shear stress lb ft

ρ

= Weight density of fluid lbm ft

Rp

= Reynolds number for pipe

Ra

= Reynolds number for annulus

(

2

)

(

3

)

)

PVaa = Apparent viscosity for annulus

PVap = Apparent viscosity for pipe (cp ) PV = Plastic viscosity (cp )

PV x = Plastic viscosity (lb sec ft 2 ) = (PV 47880.26)

( = Yield point (lb

YP = Yield point lb 100 ft 2

YPx

ft 2 )

)

Bit Hydraulic Power Bit Hydraulic Power is calculated using the flow rate entered in the input section of the Rate dialog. Bit Hydraulic Power can be used to select nozzle sizes for optimal hydraulics. Bit Hydraulic Power is not necessarily maximized when operating the pump at the maximum pump horsepower. Bit Hydraulic Power is calculated using the following equation:

Bit Hydraulic Power (hp) =

QPb . 1714

Where:

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Q

= Circulation rate, gpm

Pb

= Pressure loss across bit nozzles, psi

Bit Pressure Loss Calculations Bit Pressure Loss represents the pressure loss through the bit, and is calculated as follows.

∆Pbit =

ρV 2 2C d2 g c

Where:

(lb

ρ

= Fluid density,

V

= Fluid velocity, (ft/sec)

Cd

= Nozzle coefficient, .95

gc

= 32.17

P

= Pressure

ft 3

)

( ft / sec 2 )

(lb

ft 2

)

Derivations for PV, YP, 0-Sec Gel and Fann Data Derive PV, YP, and 0-Sec Gel from Fann Data

PV = Θ 600 − Θ 300 YP = 2Θ 300 − Θ 600 0 − SecGel = Θ 3

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Derive Fann Data from PV, YP, and 0-Sec Gel Θ 300 = PV + YP Θ 600 = 2 PV + YP Θ 3 = 0 − SecGel

ECD Calculations

ECD =

Ph + Pf

.052( Dtvd )

Ph = Wmud Dtvd (.052)

Pf = ∑

∆P (∆Dmd ) ∆L

Where: ECD

Wmud Ph Pf ∆P ∆L

= Equivalent circulating density, (ppg) = Fluid weight, (ppg) = Hydrostatic pressure change to ECD point. (psi) = Frictional pressure change to ECD point (psi) = Change in pressure per length along the annulus section (psi/ft). This is a function of the pressure loss model chosen.

Dtvd

= True vertical depth of point of interest, (ft)

∆Dmd = Annulus section length (ft) 0.052

306

= conversion constant from (ppg)(ft) to psi

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Graphical Analysis Calculations Although the Graphical Analysis and Optimization Planning analysis modes both optimize bit hydraulics, the methods used are different. Because the methods are different, the results may also be different. The following steps outline the general procedure used to perform a Graphical Analysis. 1. A total system pressures loss is specified on the Pump Limits dialog. 2. A maximum flow rate is determined that will cause the parasitic pressure loss to equal the total system pressure loss. (This will represent zero pressure loss through the bit, or infinite bit TFA.) 3. The increment flow rate is established as the maximum flow rate divided by 100. 4. The initial analysis flow rate is set to 0.1 gpm. 5. At the analysis flow rate, the pressure loss through the drillstring, annulus and surface equipment is calculated. These combined pressure losses are the parasitic pressure losses at this flow rate. 6. The parasitic pressure loss is subtracted from the maximum pump pressure to determine the pressure loss at the bit. 7. The pressure loss through the bit and the flow rate are used to calculate the bit TFA (total flow area). 8. The Impact Force, Nozzle Velocity, and Bit Hydraulic Power are calculated from the bit TFA, pressure loss at the bit, and the flow rate. 9. The next analysis flow rate is determined by adding the increment flow rate to the existing analysis flow rate and then steps five through nine are repeated. 10. The results are presented in several graphical formats via the Hydraulics Analysis View Menu.

Hole Cleaning Methodology and Calculations The Hole Cleaning model is based on a mathematical model that predicts the critical (minimum) annular velocities/flow rates required to

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remove or prevent a formation of cuttings beds during a directional drilling operation. This is based on the analysis of forces acting on the cuttings and its associated dimensional groups. The model can be used to predict the critical (minimum) flow rate required to remove or prevent the formation of stationary cuttings. This model has been validated with extensive experimental data and field data. By using this model, the effects of all the major drilling variables on hole cleaning have been evaluated and the results show excellent agreement between the model predictions and all experimental and field results. The variables considered for hole cleaning analysis include • • • • • • • • • • • • •

Cuttings density Cuttings load (ROP) Cuttings shape Cuttings size Wellpath Drill pipe rotation rate Drill pipe size Flow regime Hole size Mud density Mud rheology Mud velocity (flow rate) Pipe eccentricity

Calculations and equation coefficients to describe the interrelationship of these variables were derived from extensive experimental testing.

Calculate

n, K,τ y , and Reynold’s Number

(3.32)(log10)(YP + 2 PV ) (YP + PV ) (PV + YP) K=

n=

511 τ y = (5.11K )n

RA =

308

ρVa ( 2−n ) (DH − DP )

n

(2 3)G fa K

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Concentration Based on ROP in Flow Channel

Co =

(V D

(V D r

r

2

B

2

)

1471

)

B

1471 + Qm

Fluid Velocity Based on Open Flow Channel

Va =

24.5Qm

DH − DP 2

2

Coefficient of Drag around Sphere

If Re < 225 then,

CD =

22

Ra

else,

C D = 1.5

Mud carrying capacity

CM

D  4 g  c ( ρ c − ρ ) 12  =  3 ρC D

Settling Velocity in the Plug in a Mud with a Yield Stress 1

 4 gDc1+ bn ( ρ c − ρ  2 − b ( 2 − n ) U sp =   1− b  3 aK b ρ c 

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Where: a = 42 .9 − 23 . 9 n b = 1 − 0 . 33 n

Angle of Inclination Correction Factor

C a = (sin (1.33α ))

1.33

 5   DH

  

0.66

Cuttings Size Correction Factor

C s = 1.286 − 1.04 Dc

Mud Weight Correction Factor

If

( ρ < 7.7)

then

C m = 1.0 else C m = 1.0 − 0.0333( ρ − 7.7 )

Critical Wall Shear Stress

τwc = [ag sin(∝)( ρc − ρ ) Dc ρ b / 2 ] 1+ b

2n 2n − 2b + bn

Where:

310

a

= 1.732

b

= -0.744

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Critical Pressure Gradient

Pgc = 2τwc ro 2 rh [1− (

rh

) ]

Total Cross Sectional Area of the Annulus without Cuttings Bed

AA =

(

2 2 π DH − DP

4

)

144

Dimensionless Flow Rate

n 1 b rp 2 rp 2−( 2−n )b 2(1 + 2n) 2−( 2− n )b ∏ g c = ∏[8 × ] × (1 − ( ) )(1 − ( ) ] 1 rh rh (a) b

Where: a

= 16

b

=1

Critical Flow Rate (CFR)

Qcrit = r h [ 2

ρgc1 / c rh Kρ

(

(

1 c ) c + n 2−c( 2− n)

1 ) c −1

]

∏ gc

Correction Factor for Cuttings Concentration

C BED = 0.97 − (0.00231µ a )

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Cuttings Concentration for a Stationary Bed by Volume

 Q C bonc = C BED 1.0 − m Qcrit 

 (1.0 − φ B )(100) 

Where:

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DB DH DP DTJ

= Bit diameter

DC

= Cuttings diameter

τy

= Mud yield stress

G fa

= Power law geometry factor

RA

= Reynolds number

ρ ρc Va VR

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= Annulus diameter = Pipe diameter = Tool joint diameter

= Fluid density = Cuttings density = Average fluid velocity for annulus = Rate of penetration, ROP

VCTV Vso VSV VCTFV

= Cuttings travel velocity

VTC K n a, b, c

= Total cuttings velocity

YP PV QC

= Yield point = Plastic viscosity = Volumetric cuttings flow rate

Qm

= Volumetric mud flow rate

Qcrit Co CD Cm

= Critical flow rate for bed to develop

= Original slip velocity = Slip velocity = Critical transport fluid velocity

= Consistency factor = Flow behavior index = Coefficients

= Cuttings feed concentration = Drag coefficient = Mud carrying capacity

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CA CS C mud C BED

= Angle of inclination correction factor

Cbonc U sp

= Cuttings concentration for a stationary bed by volume

Us U mix

= Average settling velocity in axial direction

α φB µa λp

= Cuttings size correction factor = Mud weight correction factor = Correction factor for cuttings concentration

= Settling velocity

= Average mixture velocity in the area open to flow

= Wellbore angle = Bed porosity = Apparent viscosity = Plug diameter ratio

g

= Gravitational coefficient

r0

= Radius of which shear stress is zero

rp

= Radius of drill pipe

rh

= Radius of wellbore or casing

Pgc

= Critical frictional pressure gradient

τ wc

= Critical wall shear stress

Bit Impact Force Impact force is calculated using the flow rate entered in the input section of the Rate dialog. Impact force is a parameter that can be used to select nozzle sizes for optimal hydraulics. Impact force is calculated using the following equation:

 ρ   g VQ  c

Im pact Force (lbf) = 

Where:

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(

)

ρ Q gc

= Density of fluid lb ft

V

= Velocity through the bit (ft/sec)

3

3

= Circulation rate ( ft / s ) = Gravitational constant, 32.17 ft sec

2

Nozzle Velocity Velocity is calculated using the flow rate entered in the input section of the Rate Dialog. This is not necessarily the maximum velocity that can be achieved through the bits. Nozzle velocity is a parameter that can be used to select nozzle sizes for optimal hydraulics. Velocity is calculated using the following equation.

Nozzle Velocity (ft/sec) =

Q 2.96A

Where:

Q A

= Circulation rate, gpm 2 = Total flow area of bit, in

Optimization Planning Calculations Although the Graphical Analysis and Optimization Planning analysis modes both optimize bit hydraulics, the methods used are different. Because the methods are different, the results may also be different. The following steps outline the general procedure used to perform a Optimization Planning. 1. Determine the optimum flow rate. 2. If the optimum flow rate is below the minimum annular velocity specified on the Solution Constraints dialog, increase it until all annulus sections have a velocity greater than, or equal to, the minimum allowed. Landmark

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3. If turbulent flow is not allowed (as specified on the Solution Constraints dialog), and any annulus section is in turbulent flow, decrease the optimum flow so that no annulus sections are in turbulent flow. This may place the optimum flow rate below the minimum annular velocity. If there is a conflict between the minimum velocity and the flow regime, the controlling factor is the flow regime. 4. Select the actual bit jets from the optimum TFA (total flow area), and the number of nozzles and minimum nozzle diameter specified on the Solution Constraints Dialog.This will almost always result in a TFA greater than the optimum. 5. If the total system pressure drop is less than the maximum pump pressure specified on the Solution Constraints Dialog, increase the flow rate to use 100% of the allowed pump pressure. If the increase will violate the annular flow regime, it is ruled that the increase is not allowed. (The flow regime is controlling.)

Optimization Well Site Calculations ∆PparaL = ∆PsysL − ∆PbitL

∆PparaH = ∆PsysH − ∆PbitH

∆PbitH =

∆PbitL =

S=

316

ρQ H 2 2g cC 2 A2

ρQ L 2 2 g cC 2 A2

log(∆PparaH ∆PparaL ) log(QH QL )

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K=

∆PparaH QH

s

=

∆PparaL QL

s

∆P = KQ s

1

QHP

 ∆Pmax  S  =   K (S + 1) 

QIF

 2∆Pmax  S  =   K (S + 2 ) 

1

Calculate parasitic pressure loss for optimum power

∆PparaHP @ QHP

Calculate parasitic pressure loss for impact force

∆PparaIF @ QIF

Calculate pressure loss allowed for bit @ optimum flow rates

∆PbitoptHP = ∆Pmax − ∆PparaHP

∆PbitoptIF = ∆Pmax − ∆PparaIF

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Calculate bit total flow area (TFA) for each bit pressure loss at optimum flow rates

AHP =

AIF =

ρQHP 2 2 g c C 2 ∆PbitopHP

ρQIF 2 2 g c C 2 ∆PbitopIF

Using the maximum number of nozzles and the minimum Nozzle size, determine the number and size of the nozzles to equal the two total flow area values. Where:

QH

( ft = High flow rate, ( ft

Q HP

= Flow rate at optim um horsepower,

QL

3 3

sec )

sec )

Q IF

( ft = Flow rate at optim um im pact force, ( ft

A

= Bit TFA used for the pressure tests,

ρ

( ft ) = Bit TFA for im pact force, ( ft ) = Fluid weight, (lbm ft )

C

= Shape factor, .95 for bit

A HP A IF

318

= Low flow rate,

sec )

3 3

sec )

( ft ) 2

2

= Bit TFA for optim um power,

2

3

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( ft

sec 2

)

gc

= Gravitational constant,

S K

= Power law exponent for parasitic pressure loss = Power law coefficient for parasitic pressure loss,

(lbf

)(

ft 2 sec ft 3

)

S

(

∆ Pmax = Maximum allowed total system pressure loss, lbf

(

∆ Ppara = Parasitic pressure loss at specific flow rate, lbf

ft 2 ft 2

)

( = Bit pressure loss at pressure test high flow rate, (lbf = Bit pressure loss at pressure test low flow rate, (lbf

∆ Psys

= Total system pressure loss at specific flow rate, lbf

∆ PbitH ∆ PbitL

)

) ft ) ft ) ft 2

2

2

∆ PparaH = Parasitic pressure loss at pressure test high flow rate,

(lbf

ft 2

)

∆ PparaL = Parasitic pressure loss at pressure test low flow rate,

(lbf

ft 2 )

∆ PparaHP = Parasitic pressure loss at flow rate Q HP , (lbf ∆ PparaIF = Parasitic pressure loss at flow rate Q IF , (lbf

ft 2 )

ft 2 )

Power Law Rheology Model Rheological Equation

τ = Kγ n

Flow Behavior Index

 YP + 2 PV  n = 3.32192809 log   YP + PV 

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Consistency Factor

K=

YP + 2 PV (100) 1022 n

(

)

Average Velocity in Pipe

 4  Q  V p =   2   π  D 

Average Velocity in Annulus  Q  4   Va =   2 2   π  DH − DP 

Geometry Factor for Annulus

 (2n + 1)  n −1 G fa =   (8)  2n  n

Geometry Factor for Pipe  (3n + 1)  n −1 G fp =   (8)  4n  n

Reynolds Number for Pipe

Rp =

320

ρV p (2−n ) (D n ) g c G fp K

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Reynolds Number for the Annulus

RA =

ρV a ( 2 − n ) ( D H − D P )

n

g c (2 3)G fa K

Critical Reynolds Number for Pipe

Laminar Boundary = 3470 – 1370n Turbulent Boundary = 4270 – 1370n

Critical Reynolds Number for Annulus

Laminar Boundary = 3470 – 1370n Turbulent Boundary = 4270 – 1370n

Friction Factor for Pipe

Laminar

Fp =

16 Rp

Transition

a=

log(n ) + 3.93 50

b=

1.75 − log(n ) 7

RL = 3470 − 1370n

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 16   ( RP − RL )   a  +  F p =    b  RL   800   RT

  16   −    R    L 

Turbulent

a=

log(n ) + 3.93 50

b=

1.75 − log(n ) 7

Fp =

a RP

b

Friction Factor for Annulus

Laminar

Fa =

24 RA

Transition

322

a=

log(n ) + 3.93 50

b=

1.75 − log(n ) 7

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RL = 3470 − 1370n

 24   ( R A − RL )   a  +  Fa =    b  RL   800   RT

  24   −    R    L 

Turbulent

a=

log(n ) + 3.93 50

b=

1.75 − log(n ) 7

Fa =

a b RA

Pressure Loss in Pipe

P=

ρ

2 2 V p F p L  gc D

Pressure Loss in Annulus

P=

ρ

  2 2  Va Fa L gc  DH − DP 

Where:

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D DP

= Pipe outside diameter (ft)

DH

= Annulus diameter (ft)

Vp

= Average fluid velocity for pipe (ft/sec)

Va

= Average fluid velocity for annulus (ft/sec)

L P

= Pipe or annulus section length (ft)

Q

= Fluid flow rate

τ

= Shear stress on walls lb ft

n

= Flow behavior index

K

= Consistency factor  2 sec   ft 

ρ

= Fluid density (lbm ft 3 )

RP

= Reynolds number for pipe

RA

= Reynolds number for annulus

RL

= Reynolds number at Laminar flow boundary

Fp

= Friction factor for pipe

Fa

= Friction factor for annulus

Gp

= Geometry factor for pipe

Ga

= Geometry factor for annulus

PV YP

= Plastic viscosity = Yield point

gc

= Acceleration due to gravity, 32.174 (ft/sec)

= Pipe inside diameter (ft)

(

= Pipe or annulus pressure loss lb ft

( ft

sec )

3

(

 lb

2

n

2

)

) 

Pressure Loss Analysis Calculations The following general analysis steps are used to determine pressure losses in the various segments of the circulating system. The annular velocity or critical velocity calculations are performed within the pressure loss calculations. 1. The first step is to Calculate PV, YP, 0-Gel and Fann Data as required. The Bingham Plastic and Power Law pressure loss

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calculations require PV/YP data. If Fann data is input, PV/YP/0-Sec Gel can be calculated. Herschel Bulkley requires Fann data. If Fann data not is input on the Fluid Editor, it can be calculated from PV/YP/0-Sec Gel data. 2. Calculate work string and annular pressure losses are based on the rheological model selected using the Bingham Plastic rheology model calculations, Power Law rheology model calculations or Herschel-Bulkley rheology model calculations. 3. Calculate the bit pressure loss. 4. Calculate tool joint pressure losses, if required as specified on the Rate Dialog or the Rates Dialog. 5. Determine mud motor, or MWD pressure losses as input on the Mud Motor Catalog or the MWD Catalog. 6. Calculate the pressure losses in the surface equipment using the pipe pressure loss equations for the selected rheological model. 7. Calculate the total pressure loss by adding all pressure losses together. 8. Calculate ECD if required.

Pump Power Calculations If you are using more than one pump, the maximum pump power should be calculated as follows.

HPs = ∑

(HPN )(Pmin ) Pmax

Where:

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N Pmin

= 1 to num ber of pum ps = M inim um pum p pressure of all m axim um pum p discharge pressure ratings for pum ps activ e in the system and the surface equipm ent.

Pmax

= M axim um pum p pressure rating for each pum p, 1 thru n

HP s

= M axim um pum p horse power for the system

Pump Pressure Calculations If you have more than one active pump specified on the Circulating System, Mud Pumps tab, the Maximum Pump Pressure will be set equal to the minimum value entered for Maximum Discharge Pressure for any of the active pumps.

Shear Rate and Shear Stress Calculations Shear Stress

τ .. = (0.01065)Θ

Shear Rate

γ = (1.70333)RPM Where:

 lbf 

τ =  2   ft   1  γ =   sec  Θ RPM

326

= Fann dial reading, (deg) = Fann Speed, (rpm )

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Swab/Surge Calculations The WELLPLAN Swab/Surge model calculates the annulus pressures caused by the annular drilling fluid flow induced due to the movement of the string. During tripping operations, the pressures throughout the well will increase or decrease depending on whether the work string is being lowered or raised. A pressure increase due to a downward pipe movement is called a surge pressure, whereas the pressure increase due to an upward pipe movement is called a swab pressure. The swab/surge calculations do not model fluid wave propagation or consider gel strength of the mud.

Vtrip =

Ls tan d Ttrip

If the pipe closed, then Q pipe = 0.0 If the pipe is open and the pumps off, then

Aratio =

(A

Aopen

open

+ Aann )

Q pipe = (Vtrip )( Aclosed − Aopen )( Aratio )

If there is a surge situation, then Q pipe

is negative (up the string).

If there is a swab situation, then Q pipe is positive (down the string). If the pipe is open, and the pumps are on then,

Q pipe = Qrate

The flow rate induced by the pipe movement is:

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Qinduce = Vtrip Aclosed

If there is a surge situation, then Qinduce is positive (up the annulus). If there is a swab situation, then Q is negative (down the induce annulus).

Qann = Qinduce + Q pipe

The annular flow rate, Qann , is then used to perform frictional pressure loss calculations to determine the annulus pressure profile. If the first component is a bit then,

Aopen = ATFA

Aclosed

π

 =  ODbit  4 

2

If the first component is not a bit then,

Aopen

Aclosed

π

 =  ID pipe  4 

π

2

 =  OD pipe  4 

2

Where:

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V trip

= Trip v elocity

L s tan d = Stand length V trip

= Trip tim e per stand

Q pipe = Pipe flow rate

Q induce = Flow rate induced by pipe m ov em ent Q rate = Pum p flow rate

Q ann

= Annular flow rate

A closed = Pipe closed area A open = Pipe open area

A ratio = Ratio of pipe open area to com bined pipe and annulus ope ATFA = Bit total flow area, TFA

Tool Joint Pressure Loss Calculations

∆P =

ρKV 2 2

Where:

ρ V K R

= F luid density = F luid v elocity in the pipe = T ool-joint loss coefficient as a function of the R eynolds num ber (R ) in the pipe body = R eynold’s num ber for the pipe

If R < 1000; K = 0.0

If 1000 < R <= 3000;

K = (1.91) log( R ) − 5.64

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If 3000 < R <= 13,000;

K = 4.66 − (1.05 log( R ))

If R > 13,000; K = 0.33

Weight Up Calculations

Va = Vi

D f − Di Da − D f

Where:

330

Va

= Additive volume

Vi

= Initial volume

Di

= Initial density

Df

= Final density

Da

= Additive density

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References General Lubinski, A., et. al., “Transient Pressure Surges Due to Pipe Movement in an Oil Well”, Revue de L’Institut Francais du Petrole, May – June 1977. White, F. M., “Fluid Mechanics”, McGraw Hill, Inc., 1979. Wilkinson, W.L., “Non-Newtonian Fluids”, Pergamon Press, 1960.

Bingham Plastic Model Bourgoyne, A. T., Chenevert, M. E., Millheim, K. K., Young Jr., F. S. “Applied Drilling Engineering”, SPE Textbook Series: Volume 2.

Coiled Tubing McCann, R. C., and Islas, C. G. “Frictional Pressure Loss during Turbulent Flow in Coiled Tubing.” SPE 36345.

Hole Cleaning Clark, R. K., Bickham, K. L. “A Mechanistic Model for Cuttings Transport.” SPE paper 28306 presented at the SPE 69th Annual Technical Conference and Exhibition, New Orleans, September 25–28. Luo, Yuejin and P. A. Bern, BP Research Centre; and D. B.Chambers, BP Exploration Co. Ltd. “Flow-Rate Predictions for Cleaning Deviated Wells.” IADC/SPE 23884. Luo, Yuejin, P. A. Bern, D. B.Chambers, BP Exploration. “Simple Charts to Determine Hole Cleaning Requirements in Deviated Wells.” IADC/SPE 27486. Peden, J. M., Heriot-Watt U., Yuejin Luo. “Settling Velocity of Various Shaped Particles in Drilling and Fracturing Fluids.” SPE/IADC 16243.

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Rabia, H. Rig Hydraulics. Entrac Software: Newcastle, England (1989): Chapter 5.

Herschel Bulkley Model “The YPL Rheology Model.” BPA Research Note PRN9303, 93085ART0027. “Improved Hydraulic Models or Flow in Pipe and Annuli Using the YPL Rheology Model.” BPA Bluebook Report F93-P-12, 93026ART0243.

Optimization Well Site Scott, K.F., "A New Approach to Drilling Hydraulics", Petroleum Engineer, Sept. 1972.

Power Law Model Milheim, Keith K., Amoco Production Co.; Said Sahin Tulga, DRD Corp. “Simulation of the Wellbore Hydraulics While Drilling, Including the Effects of Fluid Influxes and Losses and Pipe Washouts.” SPE 11057 (1982). Schuh, F., Engineering Essentials of Modern Drilling, Energy Publications Division of HBJ.

Rheology Thermal Effects Annis, M. R. Journal of Petroleum Technology, August 1967. Chapman, A. J., Heat Transfer. McMillan Press. 1967. Combs, G. D. and Whitmire, L. D. Oil & Gas Journal, 30 September 1968. Dropkin, E. and Omerscales, S. “Heat transfer by Natural Convection by Fluid Confined by Parallel Plates.” ASME, February 1965. Hiller, K. H. Journal of Petroleum Technology, July 1963. Sorelle, J. Ardiolin, Bukley. “Mathematical Field Model Predicts Downhole Density Changes in Static Drilling Fluids.” SPE 11118. 332

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Wilhite G. P. “Overall Heat Transfer Coefficients in Stem and Hot water Injection Wells.” Journal of Petroleum Technology, May 1967.

Surge Swab Burkhardt, J. A. “Wellbore Pressure Surges Produced in Pipe Movement.” Journal of Petroleum Technology, June 1961. Clark, E. H. Jr. “Bottom-Hole Pressure Surges While Running Pipe.” Petroleum Engineering, January 1955. Fontenot, J. E., Clark R. K. “An Improved Method for Calculating Swab and Surge Pressures and Circulating Pressures in a Drilling Well.” SPE 4521 (1974). Schuh, F. J. “Computer Makes Surge-Pressure Calculations Useful.” Oil & Gas Journal, 3 August 1964.

Tool Joint Pressure Loss Denison, Pressure Losses Inside Tool Joints Can Alter Drilling Hydraulics", E.B., Oil & Gas Journal, Sept. 26, 1977, pg. 66. Milheim, Keith, Amoco Production Co., Tulga, Sahin, DRD Corporation, Tulsa, OK., “Simulation of the Wellbore Hydraulics While Drilling, Including the Effects of Fluid Influxes and Losses and Pipe Washouts”, SPE 11057, 1982.

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Chapter 8

Well Control Analysis Overview Well Control Analysis calculates the expected influx volume, assists with casing design in terms of shoe settings depths and expected conditions resulting from an influx, generates kill sheets, determines maximum safe drilling depth, and determines the maximum allowable influx volume. Well Control Analysis analyzes three different influx types: oil, water, and gas. The default influx type is gas. If the influx type is gas, the analysis assumes the influx is a single, methane gas bubble. Dispersed gas influxes are not modeled. The influx density is the density of methane at the current temperature and pressure. The compressibility factor, Z, is based on the critical temperature and pressure of methane. Refer to “General Assumptions and Terminology” on page 364 for more information. At the end of this chapter you will find the methodology used for each analysis mode. The methodology is useful for understanding data requirements, analysis results, as well as the theory used as the basis for the analysis. Supporting calculations and references for additional reading are also included in this chapter. In this section of the course, you will become familiar with all aspects of using the Well Control Analysis module, including: Available analysis modes Defining operating parameters Calculating the expected influx volume. Simulating the circulation of a kick Generating a kill sheet.

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Chapter 8: Well Control Analysis

Workflow The following is a suggested workflow. Many other workflows can be used. Open a Case using the Well Explorer. Refer to “Using the Well Explorer” on page 55 for instructions on using the Well Explorer. Define the hole section geometry. (Case > Hole Section Editor) Define the workstring. Use the same dialog to define all workstrings (drillstrings, tubing, liners, and so forth) (Case > String) Enter deviation (wellpath) data. (Case > Wellpath > Editor) Define the fluid used. (Case > Fluid Editor) Define the geothermal gradient. (Case > Geothermal Gradient) Specify the circulating system equipment. (Not required for all modes.) (Case > Circulating System) Specify the pore pressure gradient. (Not required for all modes.) (Case > Pore Pressure) Specify the fracture gradient. (Not required for all modes.) (Case > Fracture Gradient) Specify the choke and kill line usage, the kill method, and the slow pump information. (Case > Well Control Setup - All of this information is not required for each analysis mode. The Well Control Setup dialog has three tabs and all tabs are not required for all analysis modes.) Specify the circulating temperature. (Parameter > Temperature Distribution) Determine the type of kick and bottom hole pressure at the time of influx. (Parameter > Kick Class Determination) Calculate the expected influx volume. (Parameter > Influx Volume Estimation)

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Simulate the circulation of a kick, including pressure analysis, safe drilling depths, etc. (Parameter > Kick Tolerance) Then use the plots or animation available on the View menu. Generate a kill sheet. (Parameters > Kill Sheet) Then use the Kill Sheet or Kill Graph available using the View menu.

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Introducing Well Control Analysis The Well Control Analysis Module can be used to calculate the expected influx volume, assist with casing design in terms of shoe setting depths to handle pressures associated with controlling an influx (kick), expected conditions resulting from an influx, generate kill sheets, determine maximum safe drilling depth, and maximum allowable influx volume. Well Control Analysis analyzes three different influx types: oil, water, and gas. The default influx type is gas. If the influx type is gas, the analysis assumes the influx is a single, methane gas bubble. Dispersed gas influxes are not modeled. The influx density is the density of methane at the current temperature and pressure. The compressibility factor, Z, is based on the critical temperature and pressure of methane.

Starting Well Control Analysis There are two ways to begin the Well Control module:

338

z

You can select Well Control from the Modules Menu, and then select the appropriate analysis mode.

z

You can also click the Well Control button and then select the appropriate analysis mode from the drop down list.

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Select desired Well Control Analysis mode from submenu, or from Mode drop-down list.

Choose Well Control Analysis from the Modules Menu, or by clicking the Well Control Button.

Available Analysis Modes The Well Control Module has three available analysis modes. Each analysis mode will be discussed in this course.

Landmark

z

Expected Influx Volume: Use this analysis mode to predict the volume of an influx while drilling or after pump shut down.

z

Kick Tolerance: Use this analysis mode to simulate the circulation of a kick while drilling, a swab kick or after the pumps have shut down.

z

Kill Sheet: Use this analysis mode to quickly generate a standpipe pressure schedule.

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Calculating the Expected Influx Volume The Expected Influx Volume analysis mode predicts the volume of an influx while drilling or after the pumps have been shut down. The calculation is a function of bottom hole pressure, crew reaction times, equipment performance (closing BOPs and so forth), drilling rate of penetration, and reservoir properties. Refer to “General Assumptions and Terminology” on page 364 for more information.

Starting Expected Influx Volume Analysis Mode Select Expected Influx Volume from drop-down list.

Specify Choke and Kill Line Use For the Expected Influx Volume analysis mode, the Case > Well Control Setup dialog contains only the Choke/Kill tab. Use the Choke/Kill tab to specify choke and kill line usage, and sizes. This tab is not accessible unless the well is specified as offshore and as subsea on the Well Properties dialog. Choke and kill line information is used to calculate pressure loss in these areas. Only on subsea wells is the pressure loss in the choke and kill lines significant. If the well is a land well, you do not need to enter data into the Choke/Kill tab to use the Expected Influx Volume analysis mode. For other Well Control analysis modes, the Case > Well Control Setup dialog contains additional tabs. These tabs are not applicable to the Expected Influx Volume analysis, so these tabs are absent when using this analysis mode. Click the radio button to indicate to indicate the choke mode configuration you are using. If you are not using a kill line, do not enter the kill line ID. You only need to enter the ID of the lines in use. The Choke/Kill Line Length defaults to the length of the riser (specified on the Case > Hole Section Editor) plus the air gap specified on the

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Design Properties > General tab. You many enter another value if you wish.

Click here to indicate choke and/or kill line pressure loss.

Choke/Kill line length defaults to riser length plus elevation, but you can change it. Enter ID of lines in use.

Defining the Circulating Temperature Profile Use the Parameter > Temperature Distribution dialog to select the temperature model you want to use for the temperature calculations. The calculated temperatures are used to calculate gas pressures and volumes, but are not used to modify the density or rheology parameters of the drilling mud. The Steady State Circulation model performs a heat transfer calculation between the fluids in the annulus and the fluids in the string to determine their respective temperature profiles. This model is the most realistic temperature model offered. Refer to “Steady State Temperature” on page 403 for more information. The Geothermal Gradient model assumes the annulus and string temperature profiles are identical to the formation temperature profile. This selection uses the temperatures specified on the Case > Geothermal Gradient The Constant Temperature model assumes the mud is one temperature through the entire wellbore and string. This model is the least accurate.

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Steady State Circulation model is the most realistic model offered.

Geothermal Gradient uses temperature data input on the Case > Geothermal Gradient dialog.

Determining the Type of Kick The information on the Parameter > Kick Class Determination dialog is used to calculate the bottom hole pressures, influx volume, and kick tolerance and kick type at the moment an influx occurs. The initial mud gradient refers to the mud in the well when the kick occurred. The circulation flow rate is the pump rate during drilling prior to the influx and the kick interval gradient is the pore pressure gradient for the area of the formation that produced the kick. The Quick Look section displays the calculated kick type as determined from the bottom hole pressures. The Quick Look section also displays the circulating and static bottom hole pressures, and the calculated pressure at the depth where the kick occurred.

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The three types of kicks are a kick while drilling, a kick after pump shut down, and a swab kick. Initial Mud Gradient defaults from Case > Fluid Editor. Kick Interval Gradient defines the pore pressure where the kick occurred Quick Look section displays the type of kick that occurred. In this case, it is a “Kick While Drilling”.

Kick While Drilling

When a kick is taken while drilling, the pore pressure is higher than the dynamic bottom hole pressure.

Kick After Pump Shut Down

When a kick is taken after the circulation pumps have been shut down, the pore pressure is lower than the dynamic bottom hole pressure but higher than the static bottom hole pressure.

Swab Kick

When a kick is taken while tripping out of the hole, the pore pressure is lower than the static bottom hole pressure.

Estimating Influx Volume The Parameter > Influx Volume Estimation tabs are used to specify information required to determine the volume of the influx. The volume of the influx depends on the kick detection method, reservoir properties, crew reaction times, and the kick class determined using the Parameter > Kick Class Determination dialog.

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Setup Tab

The information displayed on the Parameter > Influx Volume Estimation > Setup tab is a summary of the results from the Kick Class Determination dialog. You can not edit the information displayed on this tab. This tab is not available when the kick is determined to be a “kick while swabbing”.

This tab displays a summary of the results from the Parameter > Kick Class Determination dialog. You can not edit the information displayed on this tab.

Kick Detection Method Tab

Use the Parameter > Influx Volume Estimation > Kick Detection Method tab to define the type of kick detection in use. You can choose from flow rate or volume variation methods. This information is used to help determine the influx size. This tab will not be available when the kick is determined to be a “kick while swabbing”. If you are using the Flowrate Variation method, you must enter the minimum flow difference that can be detected between the flow rate in and the flow rate out. For the Volume Variation method, you must enter the minimum increase in pit volume that can be practically detected. Because the change in volume is not instantaneous, you must also specify a Detection Time Delay. Detection time delay occurs primarily due to the performance of the shale shakers being used. Detection time is a function of flow rate, screen size, mud density, plastic viscosity, and expected cuttings removal performance. Flow rate detection methods have no detection time delay because the change in flow rate is noticed immediately.

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Enter the minimum Flowrate or Volume Variation that can be detected. Detection Time Delay applies only to the Volume Variation method.

Reservoir Tab

The Parameter > Influx Volume Estimation > Reservoir tab defines the reservoir properties used to determine the size of the influx. This tab is not be available when the kick is determined to be a “kick while swabbing.”

Enter the total measured depth thickness of the reservoir. This is used if the kick occurs while drilling or after pump shutdown. Enter the measured depth length of the reservoir that has been drilled. This is only used if the kick is determined to occur after pump shutdown. Because this is a kick while drilling, this field is not accessible.

Reaction Times Tab

The Parameter > Influx Volume Estimation > Reaction Times tab is used to specify crew reaction times during various events typical after taking a kick. This tab will not be available if the kick is determined to be a “kick while swabbing.” These reaction times will be used to determine influx size. You may set some of these reaction times to zero to model certain types of events. An example might be a hard shut-in.

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Enter the reaction times for the various activities.

Analyzing Results The only results available for the Expected Influx Volume analysis model are displayed on the Parameter > Influx Volume Estimation > Results tab. There are no plots, reports, or tables that display analysis results. However, there is a View > Temperature Distribution plot available for viewing wellbore temperatures.

Influx Volume Estimation Results Tab

The Parameter > Influx Volume Estimation > Results tab displays the results of the influx size estimation based on the information entered on other Influx Volume Estimation tabs.

Total influx volume after detection and closing the well in. Influx volume when first detected using the specified Kick Detection Method. The Detection Time is the calculated time to detect the influx.

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Using Plots

Temperature Distribution Plot

The Temperature Distribution plot indicates the temperature profile as calculated based on the temperature model specified on the Parameter > Temperature Distribution dialog. If you are using the steady state circulation model, this plot will display separate curves indicating the geothermal gradient, as well as the calculated string temperature and annular temperature.

The Title Bar indicates the temperature model used.

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Circulating the Kick The Kick Tolerance analysis mode is used to simulate the circulation of a kick while drilling, a swab induced kick, or a kick after the pumps have shut down. This analysis provides several plots to analyze the results. Using these plots, you can: •

Determine wellbore pressures for depths of interests while circulating a kick. • Determine the maximum pressure at each point in the wellbore. • Determine the allowable influx volume based on formation breakdown pressure. • Calculate the maximum pressure for various influx sizes at several wellbore depths. • Estimate shoe setting depth based on formation breakdown gradients. • Calculate the wellbore pressures in the well assuming all mud in the well has been displaced by gas. You can select the Kick Tolerance analysis mode from the Modules menu, or from the Mode drop-down list.

Choose Kick Tolerance analysis mode from Modules Menu, or from Mode drop-down list.

Specifying Kill Method, and Choke/Kill Line Data For the Kick Tolerance analysis mode, the Case > Well Control Setup dialog contains two tabs. Other Well Control analysis modes may contain different tabs on this dialog.

Specify Choke and Kill Line Data

The information entered into the Case > Well Control Setup dialog for the Expected Influx Volume analysis will continue to be used for the Kick Tolerance analysis. Since both analysis modes use the information entered into this tab, remember that if you change the information, it will be changed for all analysis modes.

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Select Kill Method and Enter Operational Data

The Case > Well Control Setup > Operational tab is used to specify kill method, BOP and casing pressure rating, and leakoff test results. You can choose to use either the Driller’s Method, or the Wait and Weight Method. If you choose to use the Driller’s Method, a message is added to the reports advising the pressure data is based on the assumption it is only valid for the second circulation when the kill mud is pumped down the string to the bit. For the Wait and Weight Method, the pressure data is based on the assumption the kill mud is pumped down the string while the kick is circulated out.

Select kill method.

Specify Kill Rate and Kick Data The information input on the Parameter > Kick Tolerance dialog is used to simulate the circulation of an influx taken while drilling or after pump shutdown. For a swab kick, tripping the work string back to the bottom of the hole is simulated. In this scenario, a worst case situation of passing the influx bubble with the BHA is analyzed at every depth. The information presented in the Setup section of the Kick Tolerance dialog was determined based on information input on the Parameter > Kick Class Determination dialog. The Kill Rate is the flow rate that will be used to circulate out the influx. The influx volume can be determined using the Estimated Influx Volume analysis mode or you can input another volume. The Depth of Interest is the depth in the well that you are interested in analyzing. Usually this will be a casing shoe depth. The Depth Interval to Check

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pertains to the Safe Drilling Depth analysis. This is the depth interval past the current measured depth that you want to analyze.

WELLPLAN uses corresponding density and viscosity, depending on the type of influx you select. Kill rate to circulate out the influx

Setup section is based on Kick Class Determination dialog results. The Swab Analysis Options are only available for swab kicks.

Influx volume can be determined using the Estimated Influx Volume analysis mode.

Enter measured depth that you are interested in analyzing.

Analyzing Results The Kick Tolerance analysis mode has several plots that can be used to analyze the results. These plots can be used to analyze annular pressure as the influx is circulated, allowable kick volumes, safe drilling depths, as well as pressure resulting from fully evacuating the annulus and filling it with gas. The Kick Tolerance analysis also provides a schematic to view the position and size of the kick as it is circulated out.

Using Plots

Pressure at Depth Plot

The View > Plot > Pressure at Depth plot displays how the pressure at a specified depth of interest in the annulus varies as the kill mud is pumped into the well. This plot assumes the bit is at the string depth specified on the Case > String Editor. You may choose one Depth of Interest on the Parameter > Kick Tolerance dialog. The plot also

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assumes a constant influx volume, which is specified on the same dialog. The various peaks and valleys on the plot reflect the different annular areas that result in changing lengths of annular fluids and the impact on the pressure calculations.

Depth of interest

Fracture pressure at depth of interest.

Pore pressure at depth of interest.

Changing the Data Displayed on This Plot

To change the data displayed on the View > Plot > Pressure at Depth, right-click anywhere on the plot (except on a curve), and select a different plot from the right-click menu. Using the right-click menu, you can display the pressure or EMW at the surface, mud line or ground

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level, shoe, and at the depth of interest specified on the Parameter > Kick Tolerance dialog.

Maximum Pressure Plot

The View > Plot > Maximum Pressure plot depicts the annular pressures that will occurs at any measured depth with an influx of constant volume in the well. Although you can determine from this plot what the maximum pressure will be at all measured depths, you can not determine when the high pressure was encountered as the influx was circulated out of the well. You may use this plot to determine casing burst service loads or shoe setting depths.

Casing shoe depth

The maximum annular pressure is less than fracture pressure.

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To Display This Plot Using EMW

Right-click anywhere on the plot (except on a curve), and select EMW from the right-click menu.

Allowable Kick Volume Plot

The View > Plot > Allowable Kick Volume plot displays the maximum pressure encountered during kick circulation at a specified depth of interest for a range of influx volumes. The pore pressure and fracture pressure at the depth of interest are also displayed on the plot for reference. This curve indicates annular pressure at specified depth as a function of influx volume.

The maximum allowable kick volume is displayed at the bottom of the plot.



Safe Drilling Depth Plot

The View > Plot > Safe Drilling Depth plot shows the maximum pressure at a depth of interest using a constant influx volume as the wellbore depth is increased using the specified depth interval past the current measured depth. You may want to use this plot to determine how far ahead you can drill with the casing shoe depth specified as the depth of interest. The plot includes pore pressure and fracture gradients to assist with determining maximum allowable pressures.

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Depth of interest

Maximum annular pressure at depth of interest.



Formation Breakdown Gradient Plot

The View > Plot > Formation Breakdown Gradient plot displays the maximum annular pressure, expressed as a gradient, that occurs as a result of the specified influx size. You can use this plot to determine the

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maximum pressure (expressed as a gradient) that you can encounter without exceeding the formation fracture gradient. Maximum pressure

Fracture gradient

Full Evacuation to Gas Plot

The View > Plot > Full Evacuation to Gas plot displays the pressure that will occur at any measured depth in the well as a result of entirely filling the annulus with methane. You can use this plot to determine if

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the annular pressure resulting from fully evacuating the wellbore with methane will fracture the open hole section.

Casing shoe

Notice the open hole annular pressure exceeds the fracture pressure.

Animation

Schematics

The View > Animation > Schematic is an animated simulation of the process of circulating the influx to the surface. In this animation, you can “see” the influx occurring, and then watch as the influx is circulated out of the well.

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Use these buttons to start or stop the animation and to move between animation points.

This information displays the data represented in the animation.

Kick in original position

Grid Data

Use View > Animation > Grid Data to view several calculations as a function of the volume pumped while circulating the influx.

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Generating a Kill Sheet The Kill Sheet analysis can help pre-plan a course of action in the event of a kick. This can be very helpful, especially since taking a kick can be a very serious and stressful time. It is recommended that as much of the information required for the Kill Sheet analysis is entered prior to taking a kick. This significantly reduces the information that will be required to gather and input after a kick has occurred. The Kill Sheet analysis can quickly generate a standpipe pressure schedule and a report of useful information.

Select Kill Sheet from Mode dropdown list.

Specify Kill Method, Operational Data, Slow Pumps and Choke/Kill Line Use For the Kill Sheet analysis mode, the Case > Well Control Setup dialog contains three tabs.

Specify Choke and Kill Line Data

The information entered into the Case > Well Control Setup > Choke/Kill Line tab for the Expected Influx Volume and Kick Tolerance analysis will continue to be used for the Kill Sheet analysis. Because the analysis modes use the information entered into this tab, remember that if you change the information, it will be changed for all analysis modes.

Selecting Kill Method and Entering Operational Data

The Case > Well Control Setup > Operational tab is used to specify kill method, BOP and casing pressure rating, and leakoff test results. You can choose to use either the Driller’s Method, or the Wait and Weight Method. If you choose to use the Driller’s Method, a message is added to the reports advising the user that the pressure data is based on the assumption it is only valid for the second circulation when the kill mud is pumped down the string to the bit. For the Wait and Weight Landmark

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Method, the pressure data is based on the assumption the kill mud is pumped down the string while the kick is circulated out.

Specifying Slow Pump Data

Use the Case > Well Control Setup > Slow Pumps tab to specify the slow pump information. Slow pump data can be entered only for those pumps entered on the Case > Circulating System dialog.

The pumps available in the drop-down list were defined using Case > Circulating System.

Entering Kill Sheet Data The Parameter > Kill Sheet tabs are used to collect information that will be used to generate a kill sheet.

Specifying Kick Analysis Parameters

Use the Parameter > Kill Sheet dialog to specify analysis parameters to use in the kill sheet calculations. On this dialog, specify:

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Kick Parameters: Including the measured depth of the kick, pit gain, trip margin, and shut-in drillpipe and casing pressures. This information will be used to generated the kill sheet, and pump schedule.

z

Mud Weight Up Data: Specify mud volumes (other than inside the string or in the annulus), and information defining the weight material and mixing capacities. This data will be used in the kill sheet generation.

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String and Annular Volumes: Specify the string and annular volumes. You can enter the volumes on this tab, or you can click the Default from Editors button to have this information automatically calculated from data input on the Case > String Editor and Case > Hole Section Editor.

z

String Volumes: Specify the string volumes. You can specify these directly, or you can copy them automatically from the Case > String Editor.

z

Pump Details: Identify the slow circulation data for the pump used to kill the well. This section of the dialog displays, in read only format, the information chosen from data entered on the Case > Well Control Setup > Slow Pumps tab. If the pump information you want to use is not available by clicking the button, then you must enter pump information on the Slow Pumps tab first. After the pump information is entered, you may view and select the appropriate pump on this dialog.

Enter the shut-in drill pipe and casing pressure after the well has been closed.

Enter the amount of weighting material that can be mixed per unit of time.

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Analyzing Results Plots

The View > Plot > Kill Graph plot indicates the desired stand pipe pressure as the kill mud is pumped down the string until it reaches the annulus. This plot changes based on the kill method selected.

Initial circulating pressure

Final circulating pressure

Reports

Kill Sheet Report

The View > Report > Kill Sheet report summarizes much of the input information. It also reports many additional types of information including:

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Summary of weak links

z

Weight up requirement for kill mud and trip margin

z

Pump stroke schedule

z

Volumes and capacities

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The pump stroke schedule can be used in well control operations to use drillpipe pressure schedules to maintain the bottomhole pressure at the proper value. During well control operations, the bottomhole pressure must be maintained at a value slightly higher than the formation pressure during kill operations.

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Analysis Mode Methodology The first section in this chapter discusses general analysis assumptions, and terminology used in the Well Control Module. The remaining sections cover one of the analysis modes available in the Well Control Analysis Module. In each section, the major analysis steps for the analysis mode are discussed. Within the analysis steps there may be a reference to a calculation. The title of the calculations is presented in italics for recognition. Many calculations apply to more than one analysis mode. To avoid duplicating information, the calculations are presented in alphabetical order in the section titled “Supporting Information and Calculations” on page 372. While reading through the methodology for a particular analysis mode you will notice calculation titles/names in italic. If you require more information about a particular calculation, please refer to the Supporting Information and Calculations section for additional information.

General Assumptions and Terminology Initial Influx Volume

Initial influx volume refers to the influx volume taken from the time a kick first develops through the time the kick has been brought under control (that is, when the well has been shut in). In designing for the “worst case,” the initial influx volume is the maximum expected influx volume. Of course, the volume of the influx changes once well kill procedures are instigated and the circulation of the influx up the annulus begins. Naturally, the size of the initial influx volume is dependent on how quickly the kick is detected and controlled. Smaller kicks will result in lower pressures exerted within the wellbore as the kick is circulated out of the well. Designing the well to withstand the appropriate maximum initial influx volume minimizes the risk to the well.

Influx Properties Assumptions

The type of influx can be oil, gas, or salt water. If this influx type is Gas or unspecified, WELLPLAN Well Control assumes the influx is a single bubble of “pure” methane gas. Assuming the influx to be composed of entirely methane gas is a conservative or “worst case” assumption. Methane is the lightest gas likely to be encountered in any great 364

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quantities. Methane gas exhibits the fastest gas migration up the wellbore annulus because of the large difference in its density compared with the significantly heavier drilling mud. In practice, a gas influx disperses into separate bubbles as it expands and rises through the well. WELLPLAN Well Control assumes the influx remains a single gas bubble in order to predict the worst possible pressure conditions. WELLPLAN does not model soluble gas kicks. In soluble gas kicks, the gas initially goes into solution with the drilling fluid (mud), and remains in solution until near the surface. These types of kick are difficult to detect, and are not handled by the Well Control Module.

Influx Annular Volume and Height

Smaller annular capacities between the work string and the wellbore have “longer” influx lengths for a given initial influx volume. This reduces the overall effect of the hydrostatic column on the bottom of the hole. In order to maintain a constant bottom hole pressure, higher choke pressures are required at the surface. The height of the influx equates to the overall length of the influx in the annulus. It is affected by the annular volume and the gas compressibility (expansion). The length and location of the influx in the wellbore impacts the combined effect of the hydrostatic gas/mud column in the annulus. An influx located high in the annulus, or a large (“long”) influx has higher associated choke pressures.

Choke Pressure and Influx Position

The position of the top of the influx also affects the choke pressure requirements. As the influx rises, the hydrostatic effect of the mud column above the gas influx reduces. As the influx rises in the annulus, higher choke (surface) pressures are required to maintain the bottom hole pressure. This effect is combated by allowing the gas to expand by opening the choke. A constant bottom hole pressure is required to prevent further influxes into the wellbore.

Kill Methods

The initial mud weight and the bottom hole pressure affect the choice of kill method. The common methods used are the “Driller’s Method” and

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the “Wait and Weight Method.” Both of these methods maintain constant bottom hole pressure. The safest method is the “Wait and Weight” method which can circulate the influx out of the well and kill the well in one circulation. However, concerns about gas migration can result if the “wait” period is too long. In this situation, the “Driller’s Method” may be used instead. The “Driller’s Method” kills the well in a minimum of two circulations. The first circulation circulates out the influx, and the second circulation fills the wellbore with kill mud. Higher choke pressures are required during the first circulation of the “Driller’s Method” to maintain a constant bottom hole pressure.

Expected Influx Volume During the drilling of a reservoir, a “kick” is taken when the pore pressure of the formation being drilled exceeds the effective bottom hole (circulating or hydrostatic) pressure exerted by the drilling mud. This results in formation fluids entering the well. The Expected Influx Volume analysis can be used to determine the volume of the influx. It is important to point out that the influx is assumed to be a single, methane gas bubble. The maximum size of the influx depends on several factors, including: •

• • • •

The pressure difference between the reservoir formation pressure and the effective bottom hole pressure. Based on this pressure difference, the Kick Classification calculations are used to determine the kick type. The reservoir characteristics, including porosity, permeability, and so forth The rate of penetration through the reservoir which determines how much of the reservoir is exposed The type and accuracy of the equipment used to detect the influx (flowrate or volume change detection) How quickly the well is shut in based on crew reaction times

The following are general steps performed during the analysis to determine the size of the influx. After you have determined the influx size, you can determine the effects a kick this size will have by using the Kick Tolerance analysis mode.

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1. The first step is to determine the temperature profile in the well. You can choose from three temperature profiles on the Temperature Distribution > Temperature Model tab. a) The Steady State Circulation model is the most realistic as the effect of circulation is included in the model. Refer to “Steady State Circulation Temperature Model” on page 397 for details. b) The Geothermal Gradient model assumes the temperature profile of the drilling fluid to be the same as the surrounding rock formation. The profile is based on specified surface and total depth temperatures, or on a surface temperature combined with a geothermal gradient. c) The Constant Temperature model is the least realistic and assumes one temperature throughout the well. 2. The next step is to determine the type of kick that is occurring. The type of kick is determined by the pressure difference between the reservoir formation pressure specified on the Pore Pressure dialog and the effective bottom hole pressure. The dynamic bottom hole pressures are determined by the same algorithms used by Pressure Loss Analysis calculations. The rheological model and fluid parameters that impact the analysis are specified on the Fluid Editor. WELLPLAN Well Control analysis defines three Kick Classifications including: Kick While Drilling, Kick After Pump Shutdown, and Swab Kick. Estimated influx volumes can be determined for a “Kick While Drilling” or for “Kick After Pump Shutdown.” If the kick is determined to be a “Swab Kick,” an estimated influx volume can not be determined. Refer to Kick Classification for more information. 3. Based on the kick class, the volume of influx is calculated using either the Kick While Drilling Influx Estimation calculations, or the Kick After Pump Shut Down Influx Estimation calculations.

Kick Tolerance Use this analysis mode to simulate the circulation of a kick while drilling, a swab induce kick or after the pumps have shut down.

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1. The first step is to determine the temperature profile in the well. You can choose from three temperature profiles on the Temperature Distribution > Temperature Model tab. a) The Steady State Circulation model is the most realistic as the effect of circulation is included in the model. Refer to “Steady State Circulation Temperature Model” on page 397 for details. b) The Geothermal Gradient model assumes the temperature profile of the drilling fluid to be the same as the surrounding rock formation. The profile is based on specified surface and total depth temperatures, or on a surface temperature combined with a geothermal gradient. c) The Constant Temperature model is the least realistic and assumes one temperature throughout the well. The next step is to determine the type of kick that is occurring using the Kick Classification calculations. WELLPLAN Well Control analysis defines three kick classifications including: Kick While Drilling, Kick After Pump Shutdown, and Swab Kick. The type of kick is determined by the pressure difference between the reservoir formation pressure specified on the Pore Pressure Dialog and the effective bottom hole pressure. The dynamic bottom hole pressures are determined by the same algorithms used by Pressure Loss Analysis calculations. The rheological model and fluid parameters that impact the analysis are specified on the Fluid Editor. 2. After the kick class is determined, you can choose from several analysis related to wellbore pressures during a kick. For the kicks while drilling or kicks after pump shutdown, the Pressure Loss calculations are performed by the same method used in WELLPLAN Hydraulics. Pressure loss calculations are required for these kick types to determine the annular and choke frictional pressure losses resulting from pumping kill mud through the annulus. The following analyses are available. •

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Pressure at Depth: This analysis determines the pressure at a specified depth as well as the volume of kill mud pumped. This analysis is not available for Swab Kicks because this type of kick is circulated without pumping kill mud. The results of this analysis are available on the Pressure at Depth Plot. To determine the volume of pumped, and the influx volume as the influx is circulated, the Influx Circulation Model for Kick While Drilling or Kick After Pump Shutdown calculations are performed. After the volume of the influx (and therefore the

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height of the influx in the annulus) is known, the Pressure at Depth of Interest calculations can be performed. The analysis uses several parameters input on the Kick Tolerance Dialog, including Kill Rate, Total Influx Volume, Depth of Interest, and Kill Mud Gradient. Total Influx Volume can be calculated using the Expected Influx Volume Analysis Mode. Fracture Gradient and Pore Pressure data at the Depth of Interest when plotted if available. This plot can be used to determine if the pressure at the Depth of Interest will remain within the wellbore pore and fracture pressures.

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•

Maximum Pressure: This analysis determines the maximum pressure at points along the wellbore along with the associated measured depth (from surface to maximum measured depth). The results of this analysis are available on the Maximum Pressure Plot. To determine the pressures in the well as a function of volume pumped, and the influx volume as the influx is circulated, the Influx Circulation Model for Kick While Drilling or Kick After Pump Shutdown or Influx Circulation Model for Swab Kicks calculations are performed. The analysis use several parameters input on the Kick Tolerance Dialog, including: Kill Rate, Total Influx Volume, and Kill Mud Gradient. Total Influx Volume can be calculated using the Expected Influx Volume Analysis Mode. Fracture Gradient and Pore Pressure data at the Depth of Interest are plotted when available, and the measured depth location of the last casing shoe.This plot can be used to determine if the pressure at any wellbore depth below the last casing shoe will remain within the wellbore pore and fracture pressures.

•

Allowable Kick Volume: This analysis determines the pressure for several influx volumes. The influx volume increment is calculated as the annulus volume from the kick measured depth to the measured depth of the shoe, divided by eight. The first influx volume used in the calculations is equal to the influx volume increment. Each succeeding influx volume is the last influx volume plus the influx volume increment. The analysis continues until the last influx volume fills the annulus from the kick measured depth to the measured depth of the last casing shoe. The results of this analysis are available on the Allowable Kick Volume Plot. To determine the pressures resulting from the various influx volumes, the Influx Circulation Model for Kick While Drilling or Kick After Pump Shutdown or the Influx Circulation Model for Swab Kicks calculations are performed. The analysis used several parameters input on the Kick Tolerance dialog, including: Kill Rate, Depth of Interest, and Kill Mud Gradient. Fracture Gradient and Pore Pressure data at WELLPLAN

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the Depth of Interest are plotted when available. The Allowable Kick Volume plot can be used to determine the maximum influx volume taken at the current bit measured depth that will not exceed the wellbore fracture gradient at the depth of interest. •

Safe Drilling Depth: This analysis determines the pressure resulting from an influx taken at several measured depths as the well is drilled past the current measured depth. The results of this analysis are available on the Safe Drilling Depth Plot. This analysis is performed by moving the bit location ahead, taking a kick and performing an Influx Circulation Model for Kick While Drilling or Kick After Pump Shutdown or Influx Circulation Model for Swab Kicks. The analysis uses several parameters input on the Kick Tolerance dialog, including Kill Rate, Total Influx Volume, Depth Interval to Check, and Kill Mud Gradient. Total Influx Volume can be calculated using the Expected Influx Volume Analysis Mode. Fracture Gradient and Pore Pressure data at the Depth of Interest are plotted when available. This plot can be used to determine the maximum depth where pressures related to the Total Influx Volume will remain within the wellbore pore and fracture pressures.

• Formation Breakdown Gradient: This analysis determines the pressure gradient in the wellbore at depths in the wellbore between the casing shoe measured depth and the kick measured depth. Influx Circulation Model for Swab Kicks or Influx Circulation Model for Kick While Drilling or Kick After Pump Shutdown calculations are performed to determine the pressures. The results of this analysis are available on the Formation Breakdown Gradient Plot. This plot can be used to determine if the pressure gradient at any location in the wellbore below the casing shoe will be outside the safety zone between the wellbore pore and fracture pressure gradients. For this analysis the Kill Rate, Total Influx Volume, and Kill Mud Gradient parameters input on the Kick Tolerance dialog. Total Influx Volume can be calculated using the Expected Influx Volume Analysis Mode. In addition to the measured depth location of the last casing shoe, Fracture Gradient and Pore Pressure data will be plotted if available. This plot can be used to determine if the pressure gradient at any location in the wellbore below the casing shoe will be outside the safety zone between the wellbore pore and fracture pressure gradients. •

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Full Evacuation to Gas: This analysis determines the pressure in the wellbore assuming the entire wellbore annulus is filled with methane gas. The pressure in the wellbore is due to the hydrostatic pressure of the gas as determined by the gas density WELLPLAN

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resulting from the wellbore temperature at that depth. The results of this analysis are available on the Full Evacuation to Gas plot. The analysis does not any parameters input on the Kick Tolerance dialog. Fracture gradient and pore pressure data are plotted when available.

Kill Sheet Refer to the “Kill Sheet” on page 392.

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Supporting Information and Calculations Allowable Kick Volume Calculations This analysis determines the pressure for several influx volumes. The influx volume increment is calculated as the annulus volume from the kick measured depth to the measured depth of the shoe, divided by eight. The first influx volume used in the calculations is equal to the influx volume increment. Each succeeding influx volume is the last influx volume plus the influx volume increment. The analysis continues until the last influx volume fills the annulus from the kick measured depth to the measured depth of the last casing shoe. The results of this analysis are available on the allowable kick volume plot. To determine the pressures resulting from the various influx volumes, the Influx Circulation Model for Kick While Drilling or Kick After Pump Shutdown or the Influx Circulation Model for Swab Kicks calculations are performed. The analysis uses several parameters input on the Kick Tolerance Dialog, including Kill Rate, Depth of Interest, and Kill Mud Gradient.

Estimated Influx Volume and Flow Rate Calculations The influx model is:

tD =

kt φµcRw2

If (t D > 10 ) then,

 4πhk∆P   t  V =  D   ln(t D )  µ   1 1  4πhk∆P    − Q =  2   ln(t D ) ln(t D )  µ 

else

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 2  t V =    t D0.5 + D  π  2 

2    1  1.5  t D    2πRw2 hφc  +  0.5 t D +         6π   16   

(

0.5  1 tD   t   Q =  0.5 0.5 − 0.5  +  0.5 + D  tD π 8 4π   

)

  2πhk∆P       µ 

Refer to the Viscosity And Compressibility Of Methane calculations. Where:

Q

( ) = Flow rate, (m s )

tD

= Dim ensionless tim e factor

k

= Perm eability, m

= Influx v olum e, m

V

3

3

( ) 2

t

= Tim e, one tim e step is 5 seconds, (sec)

φ

= Porosity

µ

= Gas v iscosity, Nsm

∆P

= Pressure difference between annulus fluid and form ation

h

= Height of penetration into form ation, (m )

c

= Gas com pressibility, 

Rw

= Annulus radius (m )

(

2

)

 m2  N

  

Gas Compressibility

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Tr =

T Tc

Pr =

P Pc

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A = Ωa

B = Ωb

Pr Tr ..

2.5

Pr Tr

C1 = − AB

(

)

C2 = A − B 2 − B q = −(C 2 − 0.333333)

C   r = − C1 + 2 − 0.0740740  3  

(

t = 27.0 ∗ r 2 − 4.0q 3

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If (t>0) If (q>0)

  3  1 .5  r   Φ = a cosh    ∗     q   2   

 2   Z =   3

( q ) cosh Φ3  + 0.333333 



If (q<0)

  3  1 .5  r    ∗   Φ = a sinh     − q   2   

 2  Z =    3

(

)

Φ  − q  sinh  + 0 .333333 3 

If (q=0)

Z = r . 0.333333 + 0 .333333

If (t<=0)

  3  1 .5  r   Φ = a cos    ∗     q   2   

 2  Z =    3

( q ) cos Φ3  + 0.333333 



Where: Acosh = Inverse hyperbolic cosine Asinh = Inverse hyperbolic sine Cosh = Hyperbolic cosing Sinh = Hyperbolic sine

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Ωa

= 0.427480233548

Ωb

= 0.0866403499633

T P

= Gas temperature = Gas pressure

Tc

= 207.98 K ° , critical temperature of methane

Pc

= 4601000 Pa, critical pressure of methane

Z

= Gas compressibility factor (Z factor)

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Influx Circulation Model for Kick While Drilling or After Pump Shutdown In the Influx Circulation Model for Kick While Drilling or After Pump Shutdown circulation model, the analysis is performed in a number of discrete steps with each representing a volume of mud pumped. The basic algorithm is to pump one volume increment of mud, and then determine the location of the influx and influx properties such as height, volume, and density. The mass remains constant until the influx begins to exit the annulus. By comparing the change in influx volume from one step to the next, an influx expansion factor is determined. This expansion factor is used to calculate the acceleration (beyond the pump rate) of the mud flowing above the influx in the annulus. The following equations and descriptions are a simplification of the actual algorithms employed in the software. Additional complexity arises due to the arbitrary complexity of the wellbore. Over the length of an influx bubble, the annulus cross sectional area and curvature may change multiple times. The influx circulation algorithm divides each influx solution into multiple problems distributed over constant annulus cross sections. The curvature over these sections dictates the complexity of relating measured depth to true vertical depth, which is a controlling factor in the determination of influx height. The solution is further divided into sections or reasonably constant temperature and compressibility factor (Z).

Determine influx volume

The initial influx volume (V) is input as “Total Influx Volume” on the Kick Tolerance Dialog. This volume is calculated in the case of the Allowable Kick Volume analysis.

Determine initial height of the influx

The true vertical depth length (h) of the influx is determined from the wellpath data based on the measured depth length in the annulus occupied by the initial influx volume.

Determine initial pressure

The initial pressure Pk of the influx is the “Kick Interval Pressure” specified on the Kick Class Determination Dialog.

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Pbot = Pk

Determine the influx mass

 V  P M =   bot  h  g c

λ=

  1 − e λ 

(

)

− gch ZRT

Determine the initial density

ρ=

Pbot ZRT

Determine initial influx gradient

G = ρg c

Determine initial surface pressure Ps = Pbot − ( ρg c h ) − ( ρ dm g c hdm ) − Pfchoke

Determine the mud pumped increment

Vinc = [(Va +Vs ) 80]E

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Circulate the influx out of the annulus

The following calculations are repeated until the influx has been circulated out of the annulus. Pump one increment of mud and determine the new location of the bottom of the influx. The bottom of the influx will move up the annulus by the measured depth required to hold one mud increment of volume in that annulus section.

Vinc A = MD bot − prev − MD inc

MD inc = MD bot

Determine the hydrostatic pressure of the drilling mud column below the influx. For “Wait and Weight” method, the kill mud will not enter the annulus until the total volume of mud pumped is greater than, or equal to the string volume. For the “Driller’s” method, kill mud will never enters the annulus until the influx is circulated out.

Phdm = hdm ρ dm g c Phkm = hkm ρ km g c

Determine the new pressure at the bottom of the influx

Pbot = PK − Phdm − Phkm − Pfchoke Once the bottom of the influx is moved to its new position, determine if the last volume will place the top of the influx outside of the annulus.

If the top of the influx is inside the annulus

To determine the new volume and height of the influx, a new influx height is assumed. Iteration is performed until the following sets of dependent simultaneous equations converge to a solution. The mass is a constant until the influx starts to exit the annulus.

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 V  P M =   bot  h  g c

ρ= V =

  1 − e λ 

(

)

Pbot ZRT M

ρ

If the top of the influx is outside the annulus

In this case, the volume and height are known.  V  P M =   bot  h  g c

ρ=

  1 − e λ 

(

)

Pbot ZRT

Determine the new influx gradient

G = ρg c

Determine the new surface pressure

Ps = Pbot − ( ρg c h ) − ( ρ m g c hm ) − ( ρ km g c hkm ) − Pfchoke Refer to the Gas Compressibility and Z Factor calculations.

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Where: Pbot = P r e s s u r e a t b o tto m o f in flu x

PK = In itia l k ic k p r e s s u r e Phdm = H y d r o s ta tic p re s s u re o f th e m u d fr o m th e w e ll b o tto m to th e in flu x b o tto m

Phkm = H y d r o s ta tic p re s s u re o f th e k ill m u d fr o m th e w e ll b o tto m to th e in flu x b o tto m

P fchoke = F ric tio n a l p re s s u re lo s s th ro u g h th e c h o k e a n d k ill lin e s . T h is is c a lc u la te d u s in g th e p ip e p r e s s u r e lo s s e q u a tio n s fo r th e m u d rh e o lo g y m o d e l G = In flu x p r e s s u r e g r a d ie n t M = M a s s o f in flu x V = V o lu m e o f in flu x

V a = A n n u lu s v o lu m e V s = S trin g v o lu m e V inc = M u d p u m p e d v o lu m e in c r e m e n t h

= T V D h e ig h t o f in flu x

h dm = T V D h e ig h t o f th e d r illin g m u d in th e a n n u lu s h km = T V D h e ig h t o f th e k ill m u d in th e a n n u lu s g c = G ra v ita tio n a l c o n s ta n t Z R T

ρ

= = = =

C o m p re s s ib ility fa c to r G a s c o n s ta n t In flu x te m p e ra tu re , d e te rm in e d fro m a n n u la r te m p e ra tu re p ro file In flu x d e n s ity

ρ dm

= D rillin g m u d d e n s ity

ρ km

= K ill m u d d e n s ity

A

= A n n u lu s c r o s s s e c tio n a l a r e a

MD

inc

= M e a s u re d d e p th in c re m e n t

MD

bot

= M e a s u r e d d e p th lo c a tio n o f th e in flu x b o tto m

MD i = In itia l m e a s u re d d e p th o f b it MD E

bot − prev

= P r e s s u r e m e a s u re d d e p th o f in flu x b o tto m

= P u m p E ffic ie n c y

Influx Circulation Model for Swab Kicks In this circulation model, mud circulation is not performed. The influx is removed in a number of discrete steps. The influx is moved to the top and exits the annulus as the string is moved up the annulus. As the bit is moved up, the bottom of the influx is always kept at the same depth as the bit. Each step is represented by a new bit location. At each depth, the influx properties, such as height, volume, and density are determined. The mass remains constant until the influx begins to exit the annulus. By comparing the change in influx volume from one step

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to the next, an influx expansion factor is determined. This expansion factor is used to calculate the acceleration of the mud being pushed above the influx. The following equations and descriptions are a simplification of the actual algorithms employed in the software. Additional complexity arises due to the arbitrary complexity of the wellbore. Over the length of an influx bubble, the annulus cross sectional area and curvature may change multiple times. The influx circulation algorithm divides each influx solution into multiple problems distributed over constant annulus cross sections. The curvature over these sections dictates the complexity of relating measured depth to true vertical depth, which is a controlling factor in the determination of influx height. The solution is further divided into sections or reasonably constant temperature and compressibility factor (Z).

Determine influx volume

The initial influx volume (V) is input as “Total Influx Volume” on the Kick Tolerance dialog. This volume is calculated in the case of the Allowable Kick Volume analysis.

Determine initial height of the influx

The true vertical depth length (h) of the influx is determined from the wellpath data based on the measured depth length in the annulus occupied by the initial influx volume.

Determine initial pressure

The initial pressure Pk of the influx is the “Kick Interval Pressure” specified on the Kick Class Determination Dialog.

Pbot = Pk

Determine influx mass

 V  P M =   bot  h  g c

Landmark

  1 − e λ 

(

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)

381


λ=

− gch ZRT

Determine initial density

ρ=

Pbot ZRT

Determine initial influx gradient

G = ρg c

Determine initial surface pressure

Ps = Pbot − ( ρg c h ) − ( ρ dm g c hdm )

Determine the measured depth increment

MDinc = MDi 80

Circulate the influx out of the annulus

The following calculations are repeated until the influx has been circulated out of the annulus. Move the bit and bottom of the influx up one measured depth increment.

MDbot = MDbot − prev − MDinc

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Determine the hydrostatic pressure of the drilling mud column below the influx. Kill mud will not enter the annulus because kill mud is not pumped for “Swab Kicks.”

Phdm = hdm ρ dm g c Determine the new pressure at the bottom of the influx. There is no choke frictional loss because mud is not being pumped.

Pbot = PK − Phdm Once the bottom of the influx is moved to its new position, determine if the last volume will place the top of the influx outside of the annulus. If the top of the influx is inside the annulus: To determine the new volume and height of the influx, a new influx height is assumed. Iteration is performed until the following sets of dependent simultaneous equations converge to a solution. The mass is a constant until the influx starts to exit the annulus.

 V  P M =   bot  h  g c

ρ=

Pbot ZRT

V=

M

  1 − e λ 

(

)

ρ

If the top of the influx is outside the annulus: In this case, the volume and height are known.

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 V  P M =   bot  h  g c

ρ=

  1 − e λ 

(

)

Pbot ZRT

Determine the new influx gradient

G = ρg c

Determine the new surface pressure

Ps = Pbot − ( ρg c h ) − ( ρ dm g c hdm ) Refer to the “Gas Compressibility (Z Factor) Model Calculations” on page 403. Where:

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Pbot

= Pressure at bottom of influx

PK

= Initial kick pressure

Phdm = Hydrostatic pressure of the drilling m ud from well bottom to influx bottom G M V h

= = = =

Influx pressure gradient M ass of influx Volum e of influx TVD height of influx

h dm = TVD height of the drilling m ud in the annulus gc

= G rav itational constant

Z R T

= = = =

ρ ρ dm

Com pressibility factor G as constant Influx tem perature, determ ined from annular tem perature profile Influx density

= Drilling m ud density

MD inc = M easured depth increm ent MD bot = M easured depth location of the influx bottom MD i = Initial m easured depth of bit MD bot − prev = Pressure m easured depth of influx bottom

Kick Classification WELLPLAN Well Control analysis defines three kick classifications including Kick While Drilling, Kick After Pump Shutdown, and Swab Kick. Estimated influx volumes can be determined for a “Kick While Drilling” or for “Kick After Pump Shutdown.” If the kick is determined to be a “Swab Kick”, an estimated influx volume can not be determined.

Kick While Drilling

Pore Pressure > Dynamic BHP > Static BHP A Kick While Drilling will occur if the formation pore pressure exceeds the dynamic circulating pressure exerted by the drilling fluid. In this case, the kick is circulated out by pumping kill mud for “Weight & Wait Method”, or by pumping drilling mud during the first circulation of the “Driller’s Method.”

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Kick After Pump Shutdown

Dynamic BHP > Pore Pressure > Static BHP A Kick After Pump Shutdown occurs if the formation pore pressure is lower than the circulating pressure of the drilling mud, and sufficient over balance exists. However, when the pumps are shut down and the circulation stops, the hydrostatic pressure of the mud alone is insufficient to counteract the pore pressure exerted. In this case, the kick is circulated out by pumping kill mud for “Weight & Wait Method”, or by pumping drilling mud during the first circulation of the “Driller’s Method”.

Swab Kick

Dynamic BHP > Static BHP > Pore Pressure With the formation pore pressure lower than the hydrostatic pressure of the mud, a kick can occur through swabbing of the formation. Swabbing can occur while pulling the work string out of the hole. In this case, the annulus pressure profile is modeled by moving the string with the influx, and mud is not pumped to move the influx. The bottom of the influx is kept even with the bottom of the bit. Expected Influx calculations are not allowed.

Kick After Pump Shut Down Influx Estimation The sequence of events during the inflow period is divided into three time periods.

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Time Period A

During Time Period A, indications of the kick are apparent by use of the rig’s kick detection equipment on surface. The sensitivity of this equipment is a factor in how much influx is taken during this period. The Estimated Influx Volume and Flow Rate Calculations are used to determine the volume of the influx and the flow rate of the mud above the influx in the annulus at the end of Time Period A. These calculations are performed for a series of five-second time steps until either the calculated volume or flow rate is detectable. For these calculations, the following conditions apply. a) The rate of penetration, ROP, is zero because there is no rotation. b) The flow rate is zero because the pumps are shut down. c) The pressure difference, ∆P , between the formation and the drilling fluid column is between the pore pressure and the calculated dynamic bottom hole pressure. The pressure difference is due to hydrostatic pressure of the mud column. Frictional pressure loss is not generated because the mud pumps are off. d) The height of penetrated reservoir, h, is constant based on the “Exposed Height” specified on the Influx Volume Estimation Reservoir tab. The values for volume of influx, V, and flowrate, Q, are calculated for each five-second time step until the end of Period A is determined based on the following conditions related to kick detection equipment.

For kicks detected by “Flowrate Variation”

Perform the calculations until the calculated flowrate, Q, is greater than or equal to the magnitude of the detectable flowrate variation.

For kicks detected by “Volume Variation”

Perform the calculations until the calculated influx volume, V, minus the flowrate, Q, times the specified “Detection Time Delay” is greater than or equal to the magnitude of the detectable volume variation.

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Time Period B

Time Period B does not apply to “Kicks After Pump Shut Down” because there is no circulation.

Time Period C

During Time Period C, the well is secured. The BOP and choke valves are made ready before the well is finally closed in. How quickly this can be achieved depends on the crew reaction times specified on the Influx Volume Estimation Reaction Times Tab. Only at this stage are further formation fluids prevented from entering the well. The initial influx volume is at a maximum. The Estimated Influx Volume and Flow Rate Calculations are used to determine the volume of the influx and the flow rate of the mud above the influx in the annulus at the end of Time Period C. These calculations are performed for a series of five-second time steps until the accumulated time steps exceed the time span of Period C. For these calculations, the following conditions apply. a) The rate of penetration, ROP, is zero because rotation has stopped. b) The mud flow rate is zero because the pumps are stopped. c) The pressure difference, ∆P , between the formation and the drilling fluid column is between the pore pressure and the calculated dynamic bottom hole pressure. The pressure difference is due to hydrostatic pressure of the mud column. Frictional pressure loss is not generated because the pumps are off. d) The height of penetrated reservoir, h, is now a constant value equal to “Exposed Height” specified on the Influx Volume Estimation Reservoir tab.

Results

The total influx volume is the sum of the influx volumes calculated for Time Period A and Time Period C. The influx volume at the time of detection is equal to the influx volume at the end of Time Period A. The kick detection time is equal to the length Time Period A.

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Kick While Drilling Influx Estimation The sequence of events during the inflow period is divided into three time periods.

Time Period A

During Time Period A, indications of the kick are apparent by use of the rigs kick detection equipment on surface. The sensitivity of this equipment is a factor in how much influx is taken during this period. The Estimated Influx Volume and Flow Rate Calculations are used to determine the volume of the influx and the flow rate of the mud above the influx in the annulus at the end of Time Period A. These calculations are performed for a series of five-second time steps until either the calculated volume or flow rate is detectable. For these calculations, the following conditions apply. a) The rate of penetration, ROP, is set to the ROP specified on the Influx Volume Estimation - Reservoir Tab. b) The flow rate is set to the drilling flow rate. c) The pressure difference, ∆P , between the formation and the drilling fluid column is between the pore pressure and the calculated dynamic bottom hole pressure. The pressure difference is due to hydrostatic pressure of the mud column, and the frictional pressure loss in the annulus.

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d) The height of penetrated reservoir, h, begins at zero, and increases based on ROP and elapsed time until the time has exceeded the length of Time Period A. For each five-secondtime step, h will increase by a factor of (5 ∗ ROP) . The values for volume of influx, V, and flowrate, Q, are calculated for each five-second time step until the end of Period A is determined based on the following conditions related to kick detection equipment.

For kicks detected by “Flowrate Variation”

Perform the calculations until the calculated flowrate, Q, is greater than or equal to the magnitude of the detectable flowrate variation.

For kicks detected by “Volume Variation”

Perform the calculations until the calculated influx volume, V, minus the flowrate, Q, times the specified “Detection Time Delay” is greater than or equal to the magnitude of the detectable volume variation.

Time Period B

During Time Period B, the drilling is stopped, the bit is pulled offbottom and the pumps are shut down. How quickly this can be achieved depends on the crew reaction times specified on the Influx Volume Estimation > Reaction Times tab. The Estimated Influx Volume and Flow Rate Calculations are used to determine the volume of the influx and the flow rate of the mud above the influx in the annulus at the end of Time Period B. These calculations are performed for a series of five-second time steps until the accumulated time steps exceed the time span of Period B. For these calculations, the following conditions apply. a) The rate of penetration, ROP, is zero because rotation has stopped. b) The flow rate is set to the drilling flow rate. c) The pressure difference, ∆P , between the formation and the drilling fluid column is between the pore pressure and the calculated dynamic bottom hole pressure. The pressure difference is due to hydrostatic pressure of the mud column and the frictional pressure loss in the annulus.

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d) The height of penetrated reservoir, h, is now a constant value equal to the time spent in Period A multiplied by the ROP specified on the Influx Volume Estimation Reservoir tab.

Time Period C

During Time Period C, the well is secured. The BOP and choke valves are made ready before the well is finally closed in. This time calculation depends on the crew reaction times specified on the Influx Volume Estimation > Reaction Times tab. Only at this stage are further formation fluids prevented from entering the well. The initial influx volume is at a maximum. The Estimated Influx Volume and Flow Rate Calculations are used to determine the volume of the influx and the flow rate of the mud above the influx in the annulus at the end of Time Period C. These calculations are performed for a series of five-second time steps until the accumulated time steps exceed the time span of Period C. For these calculations, the following conditions apply. a) The rate of penetration, ROP, is zero because rotation has stopped. b) The mud flow rate is zero because the pumps are stopped. c) The pressure difference, ∆P , between the formation and the drilling fluid column is between the pore pressure and the calculated dynamic bottom hole pressure. The pressure difference is due to hydrostatic pressure of the mud column. Frictional pressure loss is not generated because the pumps are off. d) The height of penetrated reservoir, h, is now a constant value equal to the time spent in Period A multiplied by the ROP specified on the Influx Volume Estimation Reservoir tab.

Results

The total influx volume is the sum of the influx volumes calculated for the three time periods. The influx volume at the time of detection is equal to the influx volume at the end of Time Period A. The kick detection time is equal to the length of Time Period A.

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Kill Sheet Initial Circulating Pressure

PICP = PSIDP + PP + PO

Final Circulating Pressure

ρ PFCP = PP  KM  ρ DM

  

Kill Mud Weight





P

SIDP  + ρ DM ρ KM =  D  KTVD ∗ 0.052 

Final Mud Weight

ρ FM = ρ KM + ρ TM

Kill Mud Weight Increase ρ KM = ρ KM − ρ DM

ρ KM =

392

PSIDP (0 .052 D KTVD

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Final Mud Weight Increase

∆ ρ FM = ρ FM − ρ KM ∆ ρ FM = ρ TM

Kill Mud Weighting Material Required

WTW = VT ρ W

( ρ KM − ρ DM ) ( ρ W − ρ KM )

Final Mud Weighting Material Required

WFW = VT ρ W

( ρ FM − ρ KM ) ( ρ W − ρ FM )

Formation Pressure

PF = PSIDP + PHDM

Formation Equivalent Mud Weight

ρ FEQM =

PF 0.052 DKTVD

Leak Off Equivalent Mud Weight

ρ LEQM =

Landmark

PLO + ρ LM 0.052 DSTVD

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Casing Maximum Allowed Pressure PCM = (ρ LEQM − ρ DM )DSTVD (0.052 )

Drill Pipe Pressure

PDP = PICP − ∆PHDM + ∆PFR − POC

Total Delta Frictional Pressure

ρ ∆PTFR = PP  KM  ρ DM

  − 1 

Delta Hydrostatic Pressure

∆PHD = ( ρ KM − ρ DM )(0.052)( DKMTVD )

Delta Frictional Pressure

D ∆PFR = ∆PTFR  KMMD  D KM

  

Overkill Pressure Correction

D POC = PO  KMTVD  DKTVD

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Where: PICP

= Initial circulating pressure

PSIDP

= Shut in drill pipe pressure

PP

= Pump pressure

PO

= Overkill pressure

PFCP

= Final circulating pressure

PF

= Formation pressure

PHDM

= Hydrostatic drill mud pressure at total depth

PFEQM = Formation equivalent mud weight PLO

= Leak off pressure

PCM

= Maximum casing pressure allowed

PDP

= Drill pipe pressure

PFR

= Frictional pressure

POC

= Overkill pressure correction

W TW

= Total weight of weighting material

WW

= W eight of weighting material

W FW

= Final weight of weighting material

ρ KM

= Kill mud density

ρ DM

= Drill mud density

ρ FM

= Final mud density

ρ TM

= Trip margin density

ρ LEQM

= Leak off equivalent mud density

ρ LM

= Leak off mud density

ρW

= W eighting material density

D KTVD = True vertical depth of kick

DSTVD

= True vertical depth of shoe

D KM

= Kill mud depth

D KMTVD = True vertical depth of kill mud D KMMD = Measured depth of kill mud VT

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= Total mud volume

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Pressure at Depth of Interest Pd = PP + ∆Pmf − ∆Pg − ∆Pmh Where: Pd

= P re s s u re a t th e d e p th o f in te re s t

PP

= F o rm a tio n p o re p re s s u re a s s p e c if ie d b y th e “K ic k In te rv a l P re s s u re ” o n th e K ic k C la s s D e te rm in a tio n d ia lo g

Pmf

= F ric tio n a l p re s s u re lo s s d u e to th e m u d f lo w f ro m th e d e p th o f in te re s t to th e s u rf a c e . T h e f ric tio n a l p re s s u re lo s s e s in c lu d e th e c h o k e a n d k ill lin e p re s s u re lo s s . T h e s a m e a lg o rith m s a s u s e d b y W E L L P L A N H y d ra u lic s p e rf o rm th e f ric tio n a l p re s s u re lo s s c a lc u la tio n s . T h e s e a lg o rith m s a re b a s e d o n th e rh e o lo g y m o d e l s p e c if ie d o n th e f lu id e d ito r a s w e ll a s m u d p a ra m e te rs s u c h a s P V /Y P /0 -S e c G e l o r F a n n d a ta .

Pg

= H y d ro s ta tic p re s s u re o f th e g a s c o lu m n f ro m th e b o tto m

Pmh

= H y d ro s ta tic p re s s u re o f th e m u d c o lu m n f ro m th e b o tto m

h o le lo c a tio n to th e d e p th o f in te re s t. h o le lo c a tio n to th e d e p th o f in te re s t. T h e s e in c lu d e a ll d rillin g m u d a n d k ill m u d .

Pressure Loss Analysis The following general analysis steps are used to determine pressure losses in the various segments of the circulating system. For more information concerning the pressure loss calculations, refer to the Hydraulics Analysis section in this book. 1. The first step is to Calculate PV, YP, 0-Gel and Fann data as required. The Bingham Plastic and Power Law pressure loss calculations require PV/YP data. If Fann data is input, PV/YP/0-Sec Gel can be calculated. Herschel-Bulkley requires Fann data. If Fann data not is input on the Case > Fluid Editor, it can be calculated from PV/YP/0-Sec Gel data. 2. Calculate work string and annular pressure losses based on the rheological model selected using the Bingham Plastic rheology model calculations, Power Law rheology model calculations or Herschel-Bulkley rheology model calculations. 3. Calculate the bit pressure loss.

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4. Calculate tool joint pressure losses, if required as specified on the Parameter > Rate dialog or the Parameter > Rates dialog. 5. Determine mud motor or MWD pressure losses as input on the Mud Motor Catalog or the MWD Catalog. 6. Calculate the pressure losses in the surface equipment using the pipe pressure loss equations for the selected rheological model. 7. Calculate the total pressure loss by adding all pressure losses together. 8. Calculate ECD if required.

Steady State Circulation Temperature Model To determine the temperatures along the entire wellbore length, the wellbore is divided into several sections. The following calculations are performed for each section, beginning at the annulus surface.

Set initial parameter values for first section

a =1 b=0 Tag = T0

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Calculate constants for this section

B  4 1 + 1 +  B  2 A  B  4  C2 = − + 1 1 B  2 A  B 4 C3 = 1 + 1 + 1 +  B 2 B 4 C 4 = 1 + 1 − 1 +  B 2 mc p A= 2πrpU p C1 =

B=

raU a rpU p

Calculate K parameters for this section

α= β=

e (C2 L ) (aC 4 − 1) e (C1L ) (1 − aC 3 )

GL(a − 1) + GA + (a − 1)T0 + b (1 − aC3 )e (C1L )

K2 =

Tag − T0 − βC 3

αC 3 + C 4

K 1 = αK 2 + β

Estimate annulus temperature for next section

Tag = K1C3 e (C1L ) + K 2 C 4 e (C2 L ) + GL + T0

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Calculate parameters for next section

a= b=

α +1 αC3 + C 4

(β + T0 − GA)(αC3 + C 4 ) − (βC3 + T0 )(α + 1) (αC3 + C 4 )

Repeat calculations for C constant parameters for this section. Repeat cycle for all sections.

Calculate workstring and annulus temperatures

When all depth section parameters (all K and all C) have been determined, calculate the following annulus and workstring temperatures for all depth sections.

Workstring Temperature

TP = K1e C1L + K 2 e C2 L + To + GL − GA

Annulus Temperature Ta = K 1C 3 e C1L + K 2 C 4 e C2 L + GL + To

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Where: Tp

= W orkstring tem perature at depth L, (K)

Ta

= Annulus tem perature at depth L, (K)

T ag

= Estim ate annulus tem perature at depth L, (K)

To

= Flow line m ud tem perature, (K)

G

= Geotherm al gradient based on tem perature data input on Undisturbed Tem perature tabs ,or is interpolated using the data from the Undisturbed −1 Tem perature – Additional tab . Km

(

−1

(

)

)

m

= Massflux, .kgs

cp

= Heat capacity of m ud, . Jkg .

Up

= Ov erall heat transfer coefficient through workstring, 1680 Js

Ua

= Ov erall heat transfer coefficient through annulus, 170 . 3 Js

rp

= W orkstring radius, (m )

ra L

= Annulus radius, (m )

(

−1

K −1

)

(

(

−1

−1

−2

m K −1 −2

m K −1

)

)

= Measured depth section length, (m )

Viscosity and Compressibility of Methane Calculate the viscosity of methane at temperature and pressure

P Pc T Tr = Tc Pr =

(

)

f = A 0 + A1 Pr + A 2 Pr + A 3 Pr3 + 2

T r (A 4 + A 5 Pr + A 6 Pr + A 7 Pr ) + 2

Tr

2

Tr

3

(A (A

400

+ A 9 Pr + A10 Pr 2 + A11 Pr3 ) +

8

12

µ =ef

3

+ A13 Pr + A14 Pr2 + A15 Pr3 )

µ base Tr

This value is used in the Estimated Influx Calculation

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Calculate the compressibility of methane at temperature and pressure

f 1 = 0.07408

Pr Tr3.5

P 0.4275 − 0.01501 r − 0.08664 1.5 Tr Tr Z N = f1 − f 2 Tr P 0.4275 r1 = − 0.007506 r − 0.08664 1.5 Tr Tr r D = 3Z 2 − 2 Z + Pr 1 Tr N 1 r2 = − Pr DZ f2 =

c=

r2 This value is used in the Estimated Influx Calculation Pc

Use the “Gas Compressibility (Z Factor) Model Calculations” on page 403.

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Where:

µ c

(

= Gas Viscosity at T and P, Nsm

2

(

)

= Gas compressibility at T and P, m

2

N)

T P Tc

= Kick temperature (deg Kelvin) = Kick Pressure , (Pa) = Critical temperature of methane at 207.98 deg Kelvin

Pc Tr Pr

= Critical pressure of methane at 4,602,000 Pa = Reduced temperature = Reduced pressure

µ base = Base viscosity for methane, 0.016 ∗ 10 −3 cp Z = Gas compressibility factor Constants: A0 = −2.46211820 ∗ 10 −00

A1 = −2.97054714 ∗ 10 −00 A2 = −2.86264054 ∗ 10 −01 A3 = 8.05420522 ∗ 10 −03

A4 = 2..80860949 ∗ 10 −00 A5 = −3.49803305 ∗ 10 −00 A6 = 3.60373020 ∗ 10 −01 A7 = −1.04432413 ∗ 10 −02 A8 = −7.93385684 ∗ 10 −01 A9 = 1.39643306 ∗ 10 −00 A10 = −1.49144925 ∗ 10 −01

A11 = 4.41015512 ∗ 10 −03 A12 = 8.39387178 ∗ 10 −02 A13 = −1.86408848 ∗ 10 −01 A14 = 2.03367881 ∗ 10 −02 A15 = −6.09579263 ∗ 10 −04

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References General Hage, J.I., Shell Research Rijswijk, Surewaard, J.H.G., Shell Research Rijswijk, Vullinghs, P.J.J., “Application of Research in Kick Detection and Well Control”, SIPM Paper presented at the IADC European Well Control Conference, Noordwijkerhout, June 2-4, 1992. Rabia, H., “Fundamentals of Casing Design”, Graham and Trotman, 1987.

Estimated Influx Volume and Flow Rate Van Everdingen, A.F. and Hurst, W., “The Application of the Laplace Transformation to Flow Problems in Reservoirs”, Trans. AIDE 186, 305-324, 1949.

Gas Compressibility (Z Factor) Model Calculations Redlich, O. and Kwong, J.N.S., Chem. Rev., 44,233,(1949).

Steady State Temperature Swift, S.C. and Holmes, C.S., “Calculation of Circulating Mud Temperatures”, JPT, June 1970.

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Chapter 9

Surge Analysis Overview The Surge module can be used for finding surge and swab pressures throughout the wellbore caused by pipe movement. This analysis can be useful for well planning operations when surge pressures need to be controlled and when well problems occurred that were related to pressure surges. It can also be useful for critical well designs when other surge pressure-calculation methods are not sufficiently accurate. Some specific operations when Surge is useful include: z

Tripping drill strings in deep hot holes, especially while drilling below liners

z

Running long casing strings, especially those with low clearance

z

Running liners, especially for larger sizes run in holes with minimal clearance

z

Analyzing pressure surges due to pipe movement during cementing of long strings and liners, especially where high pressure gas zones could be effected by surge pressures

z

Optimizing the selection of drilling fluid densities and pipe motions for wells with narrow margins between pore pressure and fracture gradients

z

Evaluating differential fill equipment

z

Evaluating pressure surges induced by vessel motions while drilling or running casing from a floating rig

At the end of this chapter you will find the methodology used for each analysis mode. The methodology is useful for understanding data requirements, analysis results, as well as the theory used as the basis for the analysis. Supporting calculations and references for additional reading are also included in this chapter.

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Chapter 9: Surge Analysis

In this section of the course, you will become familiar with all aspects of using the Surge module, including: Available analysis modes Defining operating parameters Defining surge operations Analyzing results

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Workflow Open the Case using the Well Explorer. Define the wellbore. (Case > Hole Section Editor) Define the workstring. Use the same dialog to define all workstrings (drillstrings, tubing, liners, and so forth) (Case > String) Enter deviation (wellpath) data. (Case > Wellpath > Editor) Define the fluids used. The fluids can be either mud or cement. You must define the fluid rheological properties, select a rheology model, and specify the temperature. You can define as many fluids as you want. (Case > Fluid Editor) If you are using more than one fluid, or you are pumping while tripping, you must specify the fluids in use on the Parameter > Job Data dialog. Define the pore pressure gradients. (Case > Pore Pressure) Define the fracture gradients. (Case > Fracture Gradient) Specify formation temperatures. (Case > Geothermal Gradient) Optional Step: Specify the formation properties if you know the elastic properties of the wellbore formations. This information will result in a more accurate analysis. (Case > Formation Properties) Optional Step: Enter the properties of the set cement. The default value for elastic modulus is 3 X 106 psi. The default value for Poisson’s ratio is 0.35. (Case > Cement Properties) Optional Step: Specify the eccentricity ratio of the annuli at different measured depths. Eccentricity reduces the pressure drop for annular flow. This information is useful for evaluating the effects of eccentricity on a vertical well. For a deviated well, the pipe is automatically assumed to be fully eccentric in the deviated sections. (Case > Eccentricity) If you are cementing or pumping while tripping: specify the fluids in the wellbore and the flowrate. (Parameter > Job Data) Otherwise, the fluid specified on the Case > Fluid Editor will be

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used. A fluid must be defined using Case > Fluid Editor before it can be used on the Parameter > Job Data dialog. Optional: Specify the use of standoff devices. (Parameter > Standoff Devices) Analyze Surge operations.

a) Select the Surge/Swab analysis mode from the Mode dropdown list. b) Using Parameter > Operations Data: — Click the Surge radio button to indicate you want to analyze for surge pressures. — Specify analysis details, including: additional depth of interest for analysis, length of stand pipe, pipe acceleration and deceleration. You must also specify the pipe depths you want to analyze, as well as the speed the pipe is moving. — Indicate whether you want to optimize the trip speeds, or if you want to use the low clearance calculations. — Specify the circulating fluid and flow rate, and whether or not you want to include mud temperature effects.

c) Analyze results. You will want to review the Surge Limit, and Transient Response plots. Use the Surge and Swab Limit plots to determine if the maximum surge pressures exceed the pore or fracture pressure gradients. Use the Transient Response plot to determine if the fluctuating pressures exceed the pore or fracture pressures. Sometimes a surge operation may experience pressures below pore pressure, or a swab operation will experience pressures above the fracture pressure. You will need to review the Transient Response plots to notice this. Analyze Swab operations

a) Select the Surge/Swab analysis mode from the Mode dropdown list. b) Using Parameter > Operations Data: — Click the Swab radio button to indicate you want to analyze for surge pressures. — Specify analysis details, including: additional depth of interest for analysis, length of stand pipe, pipe acceleration and

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deceleration. You must also specify the pipe depths you want to analyze, as well as the speed the pipe is moving. — Indicate whether you want to optimize the trip speeds, or if you want to use the low clearance calculations. — Specify the circulating fluid and flow rate, and whether or not you want to include mud temperature effects.

c) Analyze results. You will want to review the Swab Limit, and Transient Response plots. Use the Swab Limit plots to determine if the maximum swab pressures exceed the pore or fracture pressure gradients. Use the Transient Response plot to determine if the fluctuating pressures exceed the pore or fracture pressures. Sometimes a surge operation may experience pressures below pore pressure, or a swab operation will experience pressures above the fracture pressure. You will need to review the Transient Response plots to notice this. Analyze Reciprocation operations.

a) Select the Reciprocation analysis mode from the Mode dropdown list. b) Using Parameter > Operations Data: — Specify analysis details, including: additional depth of interest for analysis, length of stand pipe, pipe acceleration and deceleration, and the reciprocation length and rate. You must also specify the pipe depths you want to analyze, as well as the speed the pipe is moving. — Indicate whether you want to use the low clearance calculations. — Specify the circulating fluid and flow rate, and whether or not you want to include mud temperature effects.

c) Analyze results. You will want to review the Surge Limit, Swab Limit, and Transient Response plots. Use the Surge and Swab Limit plots to determine if the maximum surge or swab pressures exceed the pore or fracture pressure gradients. Use the Transient Response plot to determine if the fluctuating pressures exceed the pore or fracture pressures. Sometimes a surge operation may experience pressures below pore pressure, or a swab operation will experience pressures above the fracture pressure. You will need to review the Transient Response plots to notice this.

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Introducing Surge Analysis What is the Surge Module? The Surge module is a transient pressure model that can be used for finding surge and swab pressures throughout the wellbore caused by pipe movement. This analysis can be useful for well planning operations when surge pressures need to be controlled and when well problems occurred that were related to pressure surges. It can also be useful for critical well designs when other surge pressure calculation methods are not sufficiently accurate. Surge is based on a fully dynamic analysis of fluid flow and pipe motion. (Refer to “Supporting Information and Calculations” on page 439, and the “References” on page 453sections of this chapter for more information.) This analysis solves the full balance of mass and balance of momentum for pipe flow and annulus flow. Surge solutions consider the compressibility of the fluids, the elasticity of the system, and the dynamic motions of pipes and fluids. Also considered are surge pressures related to fluid column length below the moving pipe, compressibility of the formation, and axial elasticity of the moving string. In-hole fluid properties are adjusted to reflect the effects of pressure and temperature on the fluids. Surge uses the wellbore, fluid, wellpath, workstring, and other parameters specified in the Case menu options. Operational, depths of interest, and moving pipe depth parameters are specified in the Parameter menu options. The analysis results (output) can be displayed on several plots, tables, and reports, which are accessed through the View menu.

What is the Difference Between a Transient and Steady-State Model? The calculation of steady-state surge pressures is much easier and faster than the calculation of transient surge pressures. The transient pressure model included in the Surge module has several features that a steadystate model does not have. These features include: z

410

Compressibility: A transient model accounts for the compressibility and expansion of the wellbore and fluids.

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Chapter 9: Surge Analysis z

Storage: Fluids entering the well do not necessarily mean that fluids are exiting the well. For example, when viscous forces are extremely high, the surge pressure will be more related to the water compression and wellbore expansion than the steady state frictional pressure drop would indicate.

z

Elasticity: Because the drillstring can deform, the bit speed is not necessarily the draw works speed. For high yield points, pipe elasticity reduces swab pressures to an important degree.

z

Inertia: Fluid movement may be started or stopped. Therefore, positive and negative pressures may be developed in the same pipe movement. For high mud weights, fluid inertia results in higher swab pressures.

When Should I use the Transient Surge Model? Under what circumstances are the more complex transient pressure calculations justified? Generally, more accurate estimates for surge pressures are required when there is a small margin for error. Some specific operations when Surge is useful include: z

Tripping drill strings in deep hot holes, especially while drilling below liners

z

Running long casing strings, especially those with low clearance

z

Running liners, especially for larger sizes run in holes with minimal clearance

z

Analyzing pressure surges due to pipe movement during cementing of long strings and liners, especially where high pressure gas zones could be effected by surge pressures

z

Optimizing the selection of drilling fluid densities and pipe motions for wells with narrow margins between pore pressure and fracture gradients

The following examples illustrate the advantage a transient surge model can offer. z

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Example 1: Assume that the wellbore pressure is close to the fracture pressure at one point in the open hole section. In other sections of the well there is a healthy margin relative to the pore

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pressure. Using a steady state model, surge pressures would clearly need to be controlled to prevent fracture, but the swab pressures would not be a consideration. Transient analysis of swab pressures would show that rebound pressures at the end of the swab could exceed the fracture pressure and cause unexpected lost returns. z

Example 2: If the bit is nearing the casing setting depth, the wellbore pressure will be close to both the fracture pressure (top of the open hole) and the pore pressure (bottom of the open hole). surge pressures when tripping in should be maintained below the fracture pressure and above the pore pressures. In this case, there is little margin for error, so the most accurate calculation is needed.

z

Example 3: Running low clearance liners has the potential to generate large surge pressures because of the high pressure drop in the narrow annulus between the liner and wellbore. In this case, the transient model helps by including an effect not considered in a steady-state calculations: the elasticity of the work string. Steadystate models usually assume that the liner moves at the same speed as the draw works. In this case, the resistance to movement may be so high that the liner doesn’t move at all, at least not initially. As the fluid flow develops transiently, the liner will slowly descend, almost independent of the draw works speed.

Starting Surge Analysis There are two ways to begin the Surge module:

412

z

Select Surge from the Modules menu.

z

Click the Surge button

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Choose Surge from Module menu or by clicking the Surge Module button.

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Defining the Case Data Refer to “Entering Case Data” on page 162 for instructions on entering data into the Case menu options that are not discussed in this chapter.

Defining Formation Properties Use Case > Formation Properties to specify the properties of the formation if you have this information available. These data are used to calculate the compressibility of the formation. If you don’t specify data in this spreadsheet, default values of 1.45 X 106 psi for Elastic Modulus, and 0.3 for Poisson’s Ratio will be used. Most of the time you will not have this information available, and the default values are sufficient. In those situations where you have information regarding the elastic properties of the wellbore material, you can use this dialog to obtain a more accurate analysis. For most formations, the Elastic Modulus ranges between 1 X 106 and 2 X 106 psi. Poisson’s Ratio ranges between 0.2 and 0.3 for most formations. Specify the top and bottom of the formation layer, the Elastic Modulus, and Poisson’s Ratio.

Defining the Properties of the Set Cement Use the Case > Cement Properties dialog to specify the elastic properties of the set cement behind the casing, if you have this information available. These data help provide more accurate calculated results of the analysis. If you don’t specify the Cement Properties using this dialog, the analysis will use the formation properties input on the Case > Formation Properties dialog. Use this dialog to specify the properties of the set cement (behind the casing).

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Specifying Analysis Parameters Common to Surge, Swab, and Reciprocation Analysis Defining the Wellbore Fluids and Specifying Pump Rates Use the Parameter > Job Data dialog to define the fluids in the wellbore. Fluids must be defined using the Case > Fluid Editor before the fluid is accessible on this dialog. Refer to the online help for additional information about this dialog. Select the wellbore fluid from the drop-down list. The fluid must be defined on the Case > Fluid Editor before you can select in on this dialog.

It is not necessary to enter a Rate. If you are pumping and want to include this in the analysis, you must specify the flow rate on the Parameter > Job Data dialog.

Using Standoff Devices Specifying standoff devices is an optional part of the analysis. If you are using these devices, refer to “Using Standoff Devices” on page 189 for more information.

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Analyzing Surge and Swab Operations The data required for surge and swab operations is identical. The analysis plots for surge and swab are also identical. Therefore, description of both surge and swab analysis will be combined within this manual. Reciprocation analysis requires different input data, and the analysis plots are also slightly different. Because of these slight differences, reciprocation analysis will be discussed separately.

Selecting the Surge/Swab Analysis Mode Use the Mode drop-down list box to select the Surge/Swab analysis mode. By default, the Mode drop-down list is located with the menu bars. You can move the Mode drop-down list to another location if desired.

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Defining Analysis Parameters

Select the Operation Type by clicking the appropriate radio button.

Specify the depths where the bottom of the moving pipe is located. Calculations are performed at the depths specified in these columns assuming that the bottom of the moving pipe is at these depths. Specify the speed the pipe is moving when it is at these depths.

Specify one additional depth you are interested in analyzing.

If you want to include a flow rate in the analysis, specify the fluid and the flow rate on this dialog.

Check the Optimize Trip Time box to calculate the maximum speed the pipe can be tripped by increasing the calculation time. Trip time is optimized by calculating the fastest times where surge and swab pressures do not exceed the input constraints for fracture pressures and pore pressures (as specified in their respective spreadsheets). When the formation limits are exceeded, the speed is reduced until the limits are satisfied. Note: Low

Clearance Analysis Option...

The low clearance analysis is an improved analysis model that tightly couples the fluid forces with the axial forces. The low clearance analysis can take a considerable amount of time to calculate. Therefore, when you use this analysis option, it is recommended that you analyze one operation at a time, and that you limit the analysis to two moving pipe depths.

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Analyzing Surge and Swab Analysis Results Results for the Surge analysis are presented in plots, tables and a report. All results are available using the View menu.

Analyzing Results Using Plots The Surge module has several plots that will assist you while analyzing results. The plot data can be displayed as a table. Right-click inside the plot to display its context menu, and then click Graph/Grid. Each plot represents results for tripping one stand of pipe. The stand length is specified on the Parameter > Operations dialog.

Using Operation Plots

Trip Speed vs Moving Pipe Depth (Surge or Swab Analysis)

Use the View > Operation Plot > Trip Speed vs Moving Pipe Depth plot to display the trip speed at a moving pipe depth for either the surge or swab operation you are analyzing as defined on the Parameter > Operations dialog.

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Trip speeds are specified on the Parameter > Operations > Data dialog. The line will be horizontal if all trip speeds are the same.

Limit Plot (Surge or Swab Analysis)

Use the View > Operation Plot > Limit plot to view the maximum pressures at a depth of interest for either the surge or swab operation you are analyzing as defined on the Parameter > Operations dialog. Due to dynamic sloshing and backflow effects, maximum pressures during a swab may exceed the fracture pressure, and minimum pressures during a surge may drop below the pore pressure. To help you obtain a

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complete evaluation of the operation, you should review both the surge and swab limit plots.

This is an example of a limit plot for a surge analysis. The plot for swab analysis is similar.

Note: Determining if the pressure is likely to exceed the fracture

gradient, or fall below the pore pressure... You must observe the pressures on the Limit plot and compare the maximum or minimum pressure to the fracture gradient or pore pressure at the corresponding depth. Pore pressure and fracture gradient curves are not displayed on this plot. Refer to the Case > Pore Pressure or Case > Fracture Gradient spreadsheets. If the calculated pressure is greater than the fracture gradient, you should be concerned about fracturing the formation. If the calculated pressure is less than the pore pressure, you should be concerned about taking a kick.


If you prefer to display this plot as Moving Pipe Depth vs Pressure, you can use the right-click menu and select the alternate view. To access the right-click menu, right-click anywhere on the plot except on a data curve or legend.

Transient Response Plot (Surge or Swab Analysis)

Use the View > Operation Plot > Transient Response plot to display the transient pressure responses at one depth of interest for all moving pipe depths versus the time to trip one stand of pipe.

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Why use transient pressure analysis instead of steady-state?

Pressures on this plot can be compared to the specified formation pore and fracture pressure limits displayed as red areas on the plot. This plot can easily display a significant advantage of using a transient pressure analysis rather than a steady-state model. The relatively constant pressure displayed on the plot is the “steady-state” pressure. Notice the pressures above and below this steady-state pressure. These pressure changes can be significant, and are calculated using the transient pressure model. What is this plot telling me?

The pressure fluctuations at the left side of this plot display the sloshing and damping effects on the pressure behavior. This behavior is caused by the acceleration and deceleration of the pipe as the pipe motion begins and ends. As an example, during a tripping in (surge) operation, the fluid will begin to compress. As a result, the pressure will increase. Eventually the fluid will begin to flow from the annulus, and the pressure will decrease. This cycle will continue until the pressure fluctuations dampen as a result of the friction in the fluid. As this occurs, the curve flattens to a relative constant, or “steady-state” pressure as displayed on the plot. The relatively constant pressure continues until the pipe motion begins to stop. As the motion stops, the fluid continues to flow from the annulus, and therefore the pressure will decrease. Some pressure fluctuations will occur as the pipe and fluid motion ceases. The reverse of this explanation holds for a tripping out (swab) operation.

Initial movement of pipe.

Curves flatten as the initial fluid movement is taking time to reflect back. This is the “steady-state” pressure.

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Hook Load vs. Trip Time Plot (Surge or Swab Analysis)

Use the View > Operation Plot > Hook Load vs. Trip Time plot to display the hook load for a moving pipe versus trip time using the operation data specified on the Parameter > Operations Data dialog.

This is a surge operation. Tripping in has a negative change in hook load.

The rate of change in hook load decreases as you near the end of a stand.

Limit Plot @ Moving Pipe Depth (Surge or Swab Analysis)

Use the Limit Plot @ Moving Pipe Depth plot to view the maximum pressures at a moving pipe depth for surge or swab operations compared to the fracture pressure. Moving pipe depth and other analysis data is defined in the Parameter > Operations Data dialog. Due to dynamic sloshing and backflow effects, maximum pressures during a swab may exceed the fracture pressure, and minimum pressures during a surge may drop below the pore pressure. To help you obtain a complete evaluation of the operation, you should review both the surge and swab limit plots.

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Notice that the pressure during the surge operation comes very close to the fracture gradient.

Transient Response @ Moving Pipe Depth Plot (Surge or Swab Analysis)

Use the View > Operation Plot > Transient Response @ Moving Pipe Depth plot to view the transient pressure response over the time interval required to move the string the length of one stand. This plot assumes the moving pipe depth is the depth of interest. Operational parameter, including stand length, are specified on Parameter > Operations Data. The sloped portions of each curve correspond to accelerating or decelerating the pipe.

2.5 minutes is the time required to move one stand of pipe. Time begins when the pipe is at the indicated moving pipe depth. The depth increases the pipe stand length.

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Using the Miscellaneous Plots

Geothermal Gradient (Surge or Swab Analysis)

The View > Miscellaneous Plots > Geothermal Gradient plot displays the geothermal gradient based on basic formation temperature data specified in the Case > Geothermal Gradient > Standard tab and additional temperature data specified in the Case > Geothermal Gradient > Additional tab.

Surface Results Plot (Surge or Swab Analysis)

The View > Miscellaneous Plots > Surface Results plot displays the standpipe pressure, and block speed vs the time to move the string the length of one stand. Operating parameters are defined using Parameter > Operations Data. On the block speed curves, the slope of the curve at the beginning and ending of the time interval is due to pipe acceleration and deceleration.

The standpipe pressure will be zero unless you are circulating.

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Annulus Return Flowrate (Surge or Swab Analysis)

Use the View > Miscellaneous Plots > Annulus Return Flowrate plot to view the return flowrate over the time interval required to move the string the length of one stand of pipe. Operating parameters, including stand length, are defined using Parameter > Operations Data.

Transient Results (Surge or Swab Analysis)

Use the View > Miscellaneous Plots > Transient Results plot to view the velocity of the bit, or the bottom of the casing or liner, over the time interval required to move the string one stand length. Operating

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parameters, including stand length, are defined using Parameter > Operations Data.

Analyzing Results Using the Report

Report Options

The View > Report Options dialog is used to specify what additional information will be included on the report. Using this dialog, you can include or exclude much of the information defining the case you are analyzing.

Surge/Swab Report

The Reports > Surge/Swab report describes drill string and wellbore input data, mud properties, and booster pump properties.

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Analyzing Reciprocating Operations Reciprocation analysis requires different input data than surge or swab analysis, and the analysis plots are also slightly different. Because of these slight differences, reciprocation analysis will be discussed separately in this section of the manual.

Selecting the Reciprocation Analysis Mode Use the Mode drop-down list box to select the Reciprocation analysis mode. By default, the Mode drop-down list is located with the menu bars. You can move the Mode drop-down list to another location if desired.

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Defining Analysis Parameters Specify the depths where the bottom of the moving pipe is located. Calculations are performed at the depths specified.

Specify one additional depth you are interested in analyzing.

Specify the length the pipe is moved up and down for each stroke.

Specify the number of strokes rates per minute. One stroke consists of an up-and-down cycle.

Note: Low

Specify the circulation or displacement fluid to use in the analysis. The drop-down list contains the fluids defined in the Fluid Editor dialog.

Clearance Analysis Option...

The low clearance analysis is an improved analysis model that tightly couples the fluid forces with the axial forces. The low clearance analysis can take a considerable amount of time to calculate. Therefore, when you use this analysis option, it is recommended that you analyze one operation at a time, and that you limit the analysis to two moving pipe depths.

The criteria you specify here include acceleration rates, and deceleration rates. Keep in mind when you define the velocity profile data (stroke length and rate), that if the moving pipe approaches within 20 feet of the current measured depth of the well, the analysis depth is backed off from the well bottom by 20 feet plus the length of one stroke before the reciprocation analysis begins. Also, 60 seconds of circulation is simulated before the reciprocation analysis begins to ensure that steadystate circulation is achieved.

Analyzing Results Results for the Surge analysis are presented in plots, tables and a report. All results are available using the View menu.

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The Surge module has several plots that will assist you while analyzing results. The plot data can be displayed as a table. Right-click inside the plot to display its context menu, and then click Switch. Each plot represents results for reciprocating pipe the reciprocation length specified on the Parameter > Operations dialog.

Using Operation Plots

Trip Speed vs Reciprocation Depth (Reciprocation Analysis)

Use the View > Operation Plot > Trip Speed vs Reciprocation Depth plot to display the reciprocation speed at a moving pipe depth for the reciprocation operation you are analyzing as defined on the Parameter > Operations dialog.

Trip speeds are specified on the Parameter > Operations > Data dialog. The line will be horizontal if all trip speeds are the same.

Surge Limit Plot (Reciprocation Analysis)

Use the View > Operation Plot > Surge Limit Plot (Reciprocation) plot to view the maximum pressures at a depth of interest for the surge portion of the reciprocation operation you are analyzing as defined on the Parameter > Operations dialog.

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Due to dynamic sloshing and backflow effects, maximum pressures during a swab may exceed the fracture pressure, and minimum pressures during a surge may drop below the pore pressure. To help you obtain a complete evaluation of the operation, you should review both the surge and swab limit plots.

This is an example of a limit plot for the surge portion of the reciprocation analysis. The plot for swab analysis is similar.

Note: Determining if the pressure is likely to exceed the fracture

gradient, or fall below the pore pressure... You must observe the pressures on the Limit plot and compare the maximum or minimum pressure to the fracture gradient or pore pressure at the corresponding depth. Pore pressure and fracture gradient curves are not displayed on this plot. Refer to the Case > Pore Pressure or Case > Fracture Gradient spreadsheets. If the calculated pressure is greater than the fracture gradient, you should be concerned about fracturing the formation. If the calculated pressure is less than the pore pressure, you should be concerned about taking a kick.


If you prefer to display this plot as Moving Pipe Depth vs EMW, you can use the right-click menu and select the alternate view. To access the right-click menu, right-click anywhere on the plot except on a data curve or legend.

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Swab Limit Plot (Reciprocation Analysis)

Use the View > Operation Plot > Swab Limit Plot (Reciprocation) plot to view the maximum pressures at a depth of interest for the swab portion of the reciprocation operation you are analyzing as defined on the Parameter > Operations dialog. Due to dynamic sloshing and backflow effects, maximum pressures during a swab may exceed the fracture pressure, and minimum pressures during a surge may drop below the pore pressure. To help you obtain a complete evaluation of the operation, you should review both the surge and swab limit plots.

This is an example of a limit plot for the swab portion of the reciprocation analysis. The plot for surge analysis is similar.

Transient Response Plot (Reciprocation Analysis)

Use the View > Operation Plot > Transient Response plot to display the transient pressure responses at one depth of interest for all moving pipe depths versus the time to reciprocate the string the reciprocation length specified on the Parameter > Operations Data dialog. Why use transient pressure analysis instead of steady-state?

Pressures on this plot can be compared to the specified formation pore and fracture pressure limits displayed as red areas on the plot. This plot can easily display a significant advantage of using a transient pressure analysis rather than a steady-state model. The relatively constant pressure displayed on the plot is the “steady-state” pressure. Notice the pressures above and below this steady-state pressure. These pressure changes can be significant, and are calculated using the transient pressure model.

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What is this plot telling me?

For reciprocation operations, refer to the portion of the plot displaying the peaks and valleys, or sine wave shape. The overall shape of the curve displays the pressure fluctuations resulting from each stroke. (Note that if you are optimizing trip time, the strokes per minute could be adjusted.) Imposed on the overall curve shape are some “wiggles” or smaller fluctuations in pressure as the curve follows the general sine wave pattern. These “wiggles” are caused by the transient pressure changes as the fluid is opposing the motion of the string. Spikes in the reciprocation curve indicate the pressure changes resulting from the strokes.

For a reciprocation operation, this plot is modified two ways.

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z

Most of the initial circulation used to reach a steady-state prior to reciprocation is deleted from the plot. Therefore, the time scale should be viewed as incremental time, and not absolute time.

z

The reciprocation event is cut off from the plot so that only the rise/fall pressure is drawn. In other words, for slow-stroke speeds, the flat constant pressure portions of the curves are extracted from the plots. Therefore, the accelerations and decelerations along with maximums and minimums are presented for consecutive strokes, and the full transient response is cut off to allow the key information to be presented as a single plot.

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Hook Load vs. Trip Time Plot (Reciprocation Analysis)

Use the View > Operation Plot > Hook Load vs. Reciprocation Time plot to display the hook load for all moving pipe depths versus the time required to move the string the reciprocation length for the specified strokes per minute using the operation data specified on the Parameter > Operations Data dialog.

Peaks correspond to strokes. The upward string motion results in positive hookload and the downward string motion is represented by negative hookload.

Surge Limit Plot @ Reciprocation Depth (Reciprocation Analysis)

Use the View > Operation Plot > Surge Limit Plot @ Reciprocation Depth plot to view the maximum pressures at a moving pipe depth for surge operations compared to pore and fracture pressure. Moving pipe depth and other analysis data is defined in the Parameter > Operations Data dialog. Due to dynamic sloshing and backflow effects, maximum pressures during a swab may exceed the fracture pressure, and minimum pressures during a surge may drop below the pore pressure. To help you obtain a complete evaluation of the operation, you should review both the surge and swab limit plots.

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Notice that the pressure during the surge operation exceeds the fracture gradient.

Swab Limit Plot @ Reciprocation Depth (Reciprocation Analysis)

Use the View > Operation Plot > Swab Limit Plot @ Reciprocation Depth plot to view the maximum pressures at a moving pipe depth for swab operations compared to pore and fracture pressure. Moving pipe depth and other analysis data is defined in the Parameter > Operations Data dialog. Due to dynamic sloshing and backflow effects, maximum pressures during a swab may exceed the fracture pressure, and minimum pressures during a surge may drop below the pore pressure. To help you obtain a complete evaluation of the operation, you should review both the surge and swab limit plots.

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Notice that the pressure during the swab operation falls below the pore pressure.

Transient Response @ Moving Pipe Depth Plot (Reciprocation Analysis)

Use the View > Operation Plot > Transient Response @ Reciprocation Depth plot to view the transient pressure response over the time interval required to reciprocate the string the length specified. This plot assumes the moving pipe depth is the depth of interest. Operational parameter, including reciprocation length, are specified on Parameter > Operations Data. The peaks correspond to a stroke.

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Using the Miscellaneous Plots

Geothermal Gradient (Reciprocation Analysis)

The View > Miscellaneous Plots > Geothermal Gradient plot displays the geothermal gradient based on basic formation temperature data specified in the Case > Geothermal Gradient > Standard tab and additional temperature data specified in the Case > Geothermal Gradient > Additional tab.

Surface Results Plot (Reciprocation Analysis)

The View > Miscellaneous Plots > Surface Results plot displays the standpipe pressure, and block speed vs the time to move the string the length of one stand. Operating parameters are defined using Parameter > Operations Data.

The standpipe pressure will be zero unless you are circulating.

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Annulus Return Flowrate (Reciprocation Analysis)

Use the View > Miscellaneous Plots > Annulus Return Flowrate plot to view the return flowrate over the time interval required to reciprocate. Operating parameters, including reciprocation length, are defined using Parameter > Operations Data.

Transient Results (Surge or Swab Analysis)

Use the View > Miscellaneous Plots > Transient Results plot to view the velocity of the bit, or the bottom of the casing or liner, over the time interval required to reciprocate the string. Operating parameters, including reciprocation length, are defined using Parameter > Operations Data.

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Analyzing Results Using the Report

Report Options

The View > Report Options dialog is used to specify what additional information will be included on the report. Using this dialog, you can include or exclude much of the information defining the case you are analyzing.

Reciprocation Report

The View > Report > Reciprocation report describes drill string and wellbore input data, mud properties, and booster pump properties.

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Supporting Information and Calculations The material contained in this section is intended to provide you more detailed information and calculations pertaining to many of the steps presented during the descriptions of the analysis mode methodologies. If the information in this section does not provide you the detail you require, please refer to “References” on page 453 for additional sources of information pertaining to the your topic of interest.

Methodology The surge calculations are divided into two regions: the interval from the surface to the end of the pipe and the interval from the end of the pipe to bottomhole. In the upper region, pipe pressures are coupled to annulus pressures through the radial elasticity of the pipe. The interpolated method of characteristics is used to solve the fluid flow and pipe dynamics for these “Coupled Pipe-Annulus” and “Pipe-ToBottomhole” regions. The fluid flow and pipe velocity equations are solved subject to the boundary conditions given below. The maximum time step allowed is the minimum grid spacing divided by the sonic velocity. For a drill string near bottomhole, the minimum gird spacing will be the distance off bottom. In order to avoid very small time-step sizes for surges near bottomhole, a “near bottomhole” element has been defined for this special case that neglects inertia. Many of the mass equations have terms that relate the flow crosssectional area to the fluid pressures. For instance, in the “Coupled PipeAnnulus” region, increasing tubing pressure increases the tubing crosssectional area and decreases the annulus cross-sectional area. Expansion of the pipe cross-sectional area is governed by “thick-wall” pipe elastic solutions.

Pressure and Temperature Behavior of Water Based Muds Temperature and pressure behavior of water-based muds is very complex and dependent on mud composition and chemistry. There are two water-based mud models in Surge. The simplest water-based mud model used by Surge is the results from Annis combined with a comprehensive water viscosity correlation.

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The more generalized water-based mud model uses Alderman, Gavignet, Guillot, and Maitland to provide a pressure-temperature correlation for user-supplied viscometer data as well as an improved model for low shear-rate flow. The fluid model is based on the Casson equation for non-Newtonian fluids.

Viscosity Correlations of Oil Based Muds Temperature and pressure behavior of oil-based muds is equally complex and dependent on mud composition and chemistry. As for water-based muds, there are two oil-based mud models in Surge. For the simplest model, viscosity correlations for oil-based muds are based on the work of Combs and Whitmire. The more generalized oil-based mud model uses Houwen and Geehan for improved pressure-temperature correlation to viscometer data, as well as an improved model for low shear-rate flow. The fluid model is based on the Casson equation for non-Newtonian fluids.

Surge Analysis Two Analysis Regions

The dynamic surge analysis considers two distinct regions:

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z

Coupled-pipe/annulus region

z

Pipe-to-bottomhole region

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These two regions are visible in the following picture.

The Coupled-Pipe/Annulus Region Features:

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The full balance of mass and balance of momentum for pipe and annulus flow are solved.

z

Pipe and annulus pressures are coupled through the pipe elasticity. Annulus pressures caused by pipe pressures may be significant.

z

Longitudinal pipe elasticity and fluid viscous forces determine pipe displacement. Referring to the following picture, we can see that the velocity of the pipe end is not necessarily equal to the velocity

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imposed at the surface. Therefore, the block speed does not necessarily equal the speed of the bit.

z

Frictional pressure drop is solved for laminar flow in an annulus with a moving pipe for power-law fluids. Turbulent-flow frictional pressure drop uses the Dodge and Metzner friction factor for power-law fluids.

z

Fluid properties vary as a function of pressure and temperature. Plastic viscosity and yield point can vary significantly with temperature.

z

Formation elasticity, pipe elasticity and cement elasticity are all considered in determining the composite elastic response of the wellbore. For the case of a pipe cemented to the formation, use of only the pipe elasticity will not give conservative surge pressures.

The Pipe-To-Bottomhole Region Features:

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z

Balance of mass and balance of momentum for the pipe-tobottomhole flow are solved.

z

Frictional pressure drop is solved for laminar flow in the pipe-tobottomhole region for power-law fluids. Turbulent flow frictional pressure drop uses the Dodge and Metzner friction factor for power-law fluids.

z

Fluid properties vary as a function of pressure and temperature.

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Chapter 9: Surge Analysis z

Formation elasticity, pipe elasticity and cement elasticity are all considered in determining the composite elastic response of the wellbore.

Connecting the Coupled-Pipe/Annulus and the Pipe-to-Bottomhole Regions

The two regions are connected through a comprehensive set of force and displacement compatibility relations.

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The elastic force in the moving pipe is equal to the pressure below the pipe times the pipe-end area. This means that a sufficiently high pressure below the pipe could retard the pipe motion.

z

Mass-flow balances are calculated for flow through the pipe nozzle, the annulus return area and into the pipe bottomhole region. The surge force and displacement and compatibility relations are illustrated in the following diagram.

z

Pressure drops are calculated through the pipe nozzle and annulus return area on the basis of cross-sectional area changes with appropriate discharge coefficients.

z

Boundary conditions for floats were chosen to allow one-way flow through the float. Fluid is allowed to flow out of the float, otherwise the float is treated as a closed pipe.

z

Surface boundary conditions set the fluid pressures in the tube and the annulus to atmospheric pressure. The bottomhole boundary

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condition assumes a rigid floor, which requires a zero fluid velocity.

Open Annulus Calculations Mass Balance

The Mass Balance consists of three parts: z

Expansion of the hole caused by internal fluid pressure (dA/dP).

z

Compression of the fluid resulting from the changes in fluid pressure.

z

Influx (or outflux) of the fluid.

Hole expansion is a impacted by the elastic response of the formation and any casing cemented between the fluid and the formation. The fluid volume change is given by the bulk modulus, K. For drilling muds, K is a function of the composition, pressure, and temperature of the mud. K is the reciprocal of the compressibility.  1 dA 1  dP 1 ∂ + +  q=0   A dP K  dt A ∂z

Momentum Balance

This equation consists of four parts. The left side of the equation represents acceleration of the fluid. The acceleration of the fluid equals the sum of the forces on the fluid. The forces on the fluid are represented by the three terms on the right side of the equation. The first fluid force term represents the pressure or viscous force. The middle term on the right side is the drag and is a function of the fluid velocity. The final term is the gravitational force.

ρ d A dt

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q=−

∂P + h(q ) + ρg cos Θ ∂z

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Where: A P K q

ρ

= Cross-sectional area = Pressure = Fluid bulk modulus = Fluid volume flow rate = Fluid density

h = Frictional pressure drop g = Gravitational constant Θ = Angle of inclination of annulus from vertical

Coupled Pipe Annulus Calculations Four partial differential equations define this region. These balance equations are similar to the equations for the Open Annulus. However, there are two important differences. z

In the balance of mass equations, an extra term is added to account for the pressures both inside and outside of the pipe. For example, increased annulus pressure can decrease the cross-sectional area inside the pipe and increased pipe pressure can increase the crosssectional area because of pipe elastic deformation.

z

The second major difference is the effect of pipe speed on the frictional pressure drop in the annulus as given by the frictional pressure drop term.

Pipe Flow

Mass Balance

 1 dA1 1  dP1  1 dA1  dP2 1 ∂    + + +  q1 = 0 A1 ∂z  A1 dP1 K1  dt  A1 dP2  dt

Momentum Balance

∂P ρ1 d q1 = − 1 + h(q1 − A1v3 ) + ρ1 g cos Θ A1 dt ∂z

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Annulus Flow

Mass Balance

 ρ1 dA2  dP1  1 dA2 1  dP2 1 ∂    +  + + q2 = 0 A2 ∂z  A2 dP1  dt  A2 dP2 K 2  dt

Momentum Balance

ρ2 d A2 dt

q2 = −

∂P2 + h2 (q 2 , v3 ) + ρ 2 g cos Θ ∂z

Pipe Motion

The following equation is the balance of momentum for the pipe. The pipe inertia is represented by the left side of the equation. The first term of the right side is the longitudinal elasticity of the pipe (using Young’s modulus, E). The second and third items provide the hoop-stress effect (increased inside pressure shortens the pipe and increased outside pressure lengthens the pipe). The final three terms define the effect of viscous drag on the pipe. Variations in fluid velocity, relative to the pipe velocity, inside the pipe and in the annulus affect the shear stress at the pipe.

Momentum Balance

ρ3

446

d2 dt

2

v3 = E

∂ 2 v3 ∂z

2

+ f1

∂ dP1 ∂ dP2 d d d + f2 + f 3 q1 + f 4 q 2 + f 5 v3 ∂ z dt ∂z dt dt dt dt

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Where:

A1 K1 P1 q1 h

= Pipe flow area

A2 K2 P2 q2 h2

= Annulus flow area

= Pipe fluid bulk modulus = Pipe fluid pressure = Pipe fluid volume flow rate = Pipe frictional pressure drop = Pipe fluid density

ρ1

= Annulus fluid bulk modulus = Annulus fluid pressure = Annulus fluid volume flow rate = Annulus frictional pressure drop

ρ2

= Annulus fluid density

E v3

= Pipe elastic modulus = Pipe velocity

ρ3 f1 , f 2 f3 , f4 , f5 g Θ

= Pipe density = Hoop strain coefficients = Fluid shear stress coefficients = Gravitational constant = Angle of inclination from vertical

Closed Tolerance The dynamic surge fluid pressures and velocities are determined by solving two coupled partial differential equations, the balance of mass and the balance of momentum

Balance of Mass  1 dA 1  dp ∂v  A dp + K  dt + ∂z = 0  

A-1

The balance of mass consists of three effects: the expansion of the hole due to internal fluid pressure, the compression of the fluid due to changes in fluid pressure, and the influx or outflux of the fluid. The Landmark

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expansion of the hole is governed by the elastic response of the formation and any casing cemented between the fluid and the formation. The fluid volume change is given by the bulk modulus K. For drilling muds, K varies as a function of composition, pressure, and temperature. The reciprocal of the bulk modulus is called the compressibility.

Balance of Momentum

ρ

dv ∂p = − + F( v) ∂z dt

A-2

The balance of momentum equation consists of three terms. The first term in equation (A-2) represents the inertia of the fluid, i.e. the acceleration of the fluid (left side of equation A-2) equals the sum of the forces on the fluid (right side of equation A-2). The last two terms are the forces on the fluid. The first of these terms is the pressure gradient. The second is the drag on the fluid due to frictional or viscous forces. The drag is a function of the type of fluid and the velocity of the fluid and is given by the function F. Gravity terms have been left out for simplicity. The hydrostatic pressure due to gravity can be added directly to the dynamic solution to get the total pressure. For the open hole below the moving pipe, the fluid motion is governed by:

1 0 0 C vz 0 0 ρ 1 0 vt F = a 1 0 0 p z Dv / Dt 0 0 a 1 p t Dp / Dt

A-3

where the first two equations are (A-1) and (A-2) from above with C equal to the wellbore-fluid compressibility, and the last two equations describe the variation of p and v along the characteristic curve = x ± at, where a is the acoustic velocity. The capital D derivatives indicate differentiation along the characteristic curve. Subscripts here denote partial derivatives, e.g. vz = δv/δz. This system of equations is over determined, which requires:

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det

1 0 0 C 0 ρ 1 0 a 1 0 0 0 0 a 1

A-4

=0

Evaluating the determinant (A-4) defines the acoustic velocity:

a=±

1 ρC

A-5

The condition that (A-3) has a solution requires:

det

1 0 0 0 ρ 1

0 F

a 1 0 Dv / Dt 0 0 a Dp / Dt

=0

A-6

The resulting differential equations along the characteristic curve are:

Dp Dv ± ρa = ±aF Dt Dt

A-7

Equation (A-7) can be solved by integrating along the characteristic:

∆p ± ρ a ∆v = ± a ∫ F dt

A-8

The difficulty in evaluating equation (A-8) is that the integral is along the characteristic and we do not know the values of the fluid velocity along the characteristic. To better explain what this means, we will solve equation (A-8) without the frictional pressure drop term F. There are a series of grid points, xk, separated by distance a∆t. We have a wave

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moving in the positive x direction form point xk-1 and a wave moving in the negative x direction from point xk+1. On the positive characteristic:

∆ p + ρ a ∆ v = ( p kt + ∆ t − p kt −1 ) + ρ a ( v kt + ∆ t − v kt −1 ) = 0

A-9

while along the negative characteristic:

∆ p − ρ a ∆ v = ( p kt + ∆ t − p kt +1 ) − ρ a ( v kt + ∆ t − v tk +1 ) = 0

A-10

where the superscripts indicate the time of the pressures and velocities, and the subscripts indicate the grid positions. If we solve equations A-9 and A-10 simultaneously:

p tk+ ∆ t = 12 [p kt +1 + p kt −1 + ρ a ( v kt −1 − v kt +1 )] v kt + ∆ t = 12 [ v kt +1 + v kt −1 + (p tk +1 − p kt −1 ) / ρa ]

A-11

While we have the value of the function p±ρav along the characteristic from t to t+∆t, we do not know the value of either p or v until we solve at the intersection of two characteristic curves. One solution has been to assume that the frictional pressure drop does not vary much along the characteristic curve, so we can hold it constant. Equation (A-8) takes this form, using this assumption:

∆p k + ρ a ∆v k = aF( v kt −1 ) ∆t ∆p k − ρ a ∆v k = −aF( v kt +1 ) ∆t

A-12

This method works well as long as the frictional pressure drop term is small relative to the dynamic force terms, in other words, if the system is under-damped. This means that the right hand side of equation (A-12) is small relative to the right hand side of equation (A-11). If the frictional pressure drop term is large relative to the right hand side term of equation (A-11), then we say that the system is over-damped. The solution proposed in equation (A-12) is disastrous for an over-damped

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system. For instance, if the velocity changes direction along the characteristic curve, then the friction term is both too large and of the wrong sign in equation (A-12). This sort of error propagates throughout the solution system, causing dramatic instabilities. The water hammer literature recognizes this problem, called line-packing. Solution, is to make the friction term depend on the velocity at the point of calculation:

∆p k + ρ a ∆v k = aF( v kt + ∆t ) ∆t ∆p k − ρ a ∆v k = −aF( v

t + ∆t k

A-13

) ∆t

Typically, they choose a friction factor form for F:

F( v) = − 12

f ρvv Dh

A-14

This results in a quadratic equation solution for equation (A-13), assuming f stays relatively constant. If we want to include both the initial and final values of the friction term, we need to assume something about the variation of F along the characteristic curve. If we assume that F varies roughly linearly along the curve, then equation (A-8) takes the form:

∆p k + ρ a ∆v k = 12 a[F( v tk+ ∆t ) + F( v tk −1 )] ∆t ∆p k − ρ a ∆v k = − a[F( v 1 2

t + ∆t k

) + F( v

t k +1

A-15

)]∆t

If we assume that the velocity varies linearly along the curve, we need a more complex formulation, since F is assumed to be non-linear in velocity (e.g.: non-Newtonian fluid and turbulent flow). On possibility is a three-point integration formula:

∆p k + ρ a ∆v k = 14 a[F( v tk+ ∆t ) + 2F(~ v ) + F( v kt −1 )] ∆t ~ v = 1 ( v t + ∆t + v t ) 2

k

k −1

A-16

∆p k − ρ a ∆v k = − 14 a[F( v kt + ∆t ) + 2F( vˆ) + F( v kt +1 )]∆t vˆ = 12 ( v kt + ∆t + v kt +1 )

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in practice, equation (A-15) works well enough, especially with some attention paid to meshing the problem. Most errors in (A-15) can be resolved by using a finer mesh. Notice, also, that equations (A-15) or (A-16) all must be solved numerically for any realistic function F.

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References Transient Pressure Surge Mitchell, R. F. “Dynamic Surge/Swab Pressure Predictions.”, SPE Drilling Engineering, September 1988, (pages 325-333). Lal, Manohar. “Surge and Swab Modeling for Dynamic Pressures and Safe Trip Velocities.” Proceedings, 1983 IADC/SPE Drilling Conference, New Orleans (427-433). Lubinski, A., Hsu, F. H., and Nolte, K. G. “Transient Pressure Surges Due to Pipe Movement in an Oil Well.” Fevue de l’Inst. Franc. Du Pet., May — June 1977 (307-347). Wylie, E. Benjamin, and Streeter, Victor L. Fluid Transients, Corrected Edition (1983). FEB Press, Ann Arbor, Mich., (1982).

Validation Rudolf, R.L., Suryanarayana, P.V.R., Mobil E&P Technical Center, “Field Validation of Swab Effects While Tripping-In the Hole on Deep, High Temperature Wells “, SPE 39395. Samuel, G.R., Sunthankar, A., McColpin, G., Landmark Graphics, Bern, P., BPAmoco, Flynn,T., Sperry Sun, “Field Validation of Transient Swab/Surge Response with PWD Data”, SPE 67717.

Pipe and Borehole Expansion Timoshenko, S. P., and Goodier, J. N., “Theory of Elasticity”, McGrawHill Book Company, New York, 1951.

Frictional Pressure Drop Savins, F. J. “Generalized Newton (Pseudo-plastic) Flow in Stationary Pipes and Annuli.” Pet. Trans. AIME (1958). Dodge, D.W., and Metzner, A. B. “Turbulent Flow of Non-Newtonian Systems,” AIChEJ (June 1959).

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Fontenot, J. E., and Clark, R. E.: “An Improved Method for Calculating Swab and Surge Pressures and Calculating Pressures in a Drilling Well, “Society of Petroleum Engineering, October 1974 (451-462). Schuh, F. J. “Computer Makes Surge-Pressure Calculations Useful.” Oil and Gas Journal, August 1964 (96).

Pressure and Temperature Fluid Property Dependence Annis, Max R. “High Temperature Flow Properties of Water-Base Drilling Fluids.” J. Pet. Tech., August 1967. Alderman, N. J., Gavignet, A., Guillot, D., and Maitland, G. C.: “High Temperature, High Pressure Rheology of Water-Based Muds,” SPE 18035, 63rd Annual Technical Conference and Exhibition of the SPE., Houston, (1988 (187-196). Combs, G. D., and Whitmire, L. D. “Capillary Viscometer Simulates Bottom Hole Conditions.” Oil and Gas Journal, September 30, 1968 (108-113). Houwen, O. H. and Geehan, T.:”Rheology of Oil-Based Muds.” SPE15416, 61st Annual Technical Conference and Exhibition of the SPE, New Orleans (1986). Uner, D., Ozgen, C., and Tosun, I. “Flow of a Power-Law Fluid in an Eccentric Annulus” SPEDE, September 1989 (269-272). Johancsik, C. A., Friesen, D. B., and Dawson, R. “Torque and Drag in Directional Wells — Prediction and Measurement.” J. Pet. Tech., June 1984 (987-992).

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Chapter 10

Cementing-OptiCem Analysis Overview Cementing can be used to optimize cementing operations and minimize the possibility of costly cementing errors. In this section of the course, you will become familiar with all aspects of using the Cementing-OptiCem module, including: Available analysis modes Defining operating parameters Defining cement fluids Calculating centralizer placement Defining the cement job Defining analysis parameters Analyzing results

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Chapter 10: Cementing-OptiCem Analysis

Workflow Activate Cementing by clicking the

button.

Open the Case using the Well Explorer. Define the wellbore. (Case > Hole Section Editor) Define the workstring. Use the same dialog to define all workstrings (drillstrings, casings, liners, etc.) (Case > String) Enter wellpath data. (Case > Wellpath > Editor) Define the fluids used. You can define as many fluids as you want. (Case > Fluid Editor) Define the pore pressure gradients. (Case > Pore Pressure) Define the fracture gradients. (Case > Fracture Gradient) Define the geothermal gradient. (Case > Geothermal Gradient) Define the cement circulating system. (Case > Cement Circulating System) Specify centralizer information. (Parameter > Centralizer Placement) Specify cement job data including volumes, fluids used, back pressure and whether or not this is a foam job. (Parameter > Job Data) If this is a foam job, specify the foam job data. (Parameter > Foam Data) Specify wellbore temperatures, depths of interest and whether or not returns are taken at the sea floor. (Parameter > Additional Data) Specify additional pressure that may be required to seat the plug and the eccentricity (standoff) to be used in the calculations. (Parameter > Analysis Data) Analyze the results.

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Introducing Cementing Analysis What is Cementing? The Cementing module can be used to predict what occurs in the well during cementing operations. Cementing can be used to evaluate the effects of various conditions on the simulated cementing operation. You can use Cementing to calculate: • • • • • • •

Safe pump rates Surface pressure Downhole pressures Nitrogen concentration Foam volume Downhole rheology Temperature thinning of fluids

Starting Cementing Analysis There are two ways to start the Cementing Module.

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Select Cementing from the Modules menu.

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Click the Cementing button.

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Choose Cementing-OptiCem Analysis from Modules menu, or by clicking the Cementing-OptiCem Module button.

Select desired Cementing-OptiCem Analysis mode from submenu, or from Mode drop-down list.

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Defining the Case Data Refer to “Entering Case Data” on page 162 for instructions on entering data into the Case menu options. Case data specific to cementing will be covered in this chapter.

Specify the Volume Excess % The Case > Hole Section Editor is used to define the wellbore as the current workstring sees it. You can also use the Case > Hole Section Editor dialog to specify the extra percentage of annular cement volume required for an enlarged wellbore. This volume will be based on the Effective Hole Diameter field. For open hole sections, the Effective Hole Diameter is used to represent the actual size of the hole. If you specify the Effective Hole Diameter, the Volume Excess % is calculated based on Effective Hole Diameter. Similarly, if you specify the Volume Excess %, the Effective Hole Diameter will be calculated. For example, if you are drilling an 8.5 inch hole that is 10% overgauge, enter 8.5 for Hole Diameter and 10 for Volume Excess %. The extra volume will be calculated. Do not use the Volume Excess % field to raise the cement top. Use Parameter > Job Data to raise the cement top. Note: Specifying Volume Excess...

Be careful that you don’t enlarge the wellbore in the Hole Diameter field and then again using the Volume Excess % field.

Enter the Volume Excess % and the Effective Hole Diameter is calculated.

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Defining the Cement Job Defining the Cement Job Fluids Defining Spacers

Use Case > Fluid Editor to define cement spacers by specifying the basic characteristics of the fluid. You don’t need to activate the spacer. Spacer use is specified using Parameter > Job Data.

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To define a spacer, select Spacer from the Type drop-down list.

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Defining Cement Slurries

Use Case > Fluid Editor to define cement slurries by specifying the basic characteristics of the fluid. You don’t need to activate the cement. Cement use is specified using Parameter > Job Data.

To define a cement, check the Cement box.

Specify the Standoff or Calculate the Centralizer Placement Use the Parameter > Centralizer Placement dialog to calculate the spacing between multiple centralizers and/or the variable standoff between the casing and wellbore. Alternately, you can enter a manual standoff value that applies to the entire well. Before using this dialog, you should use the Centralizer catalog to specify all centralizers if you plan on using centralizers not already in the catalog. Access the Centralizer catalog using the Well Explorer. Refer to “Working With Catalogs” on page 110 for more information. Centralizer placement calculations are typically performed before wellbore simulation. These calculations can also be performed

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independently using the Centralizer Placement mode. Refer to the online help for more details concerning this dialog. The Wellbore Fluid defaults from the active fluid indicated on the Case > Fluid Editor.

You can specify a measured depth and standoff above the top of the centralized interval.

Enter the maximum and minimum distance that can be used when calculating centralizer spacing.

Defining the Cement Job Use the Parameter > Job Data dialog to define crucial job information such as tracer fluid types, rate, volume, and placement for each fluid in the cementing job. Refer to the online help for more information about this dialog.

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Note: Mud

Erodibility

Mud Erodibility as used in cementing and WELLPLAN’s Cementing-OptiCem refers to the ability of the wellbore fluid to be eroded away by a different fluid passing by it in the annulus of the well. The Mud Erodibility option is available only to Halliburton users. If you need this calculation performed, please contact your local Halliburton Zonal Isolation Group.

Defining Temperatures, Depths of Interest and Offshore Returns Information The Parameter > Additional Data dialog is used to enter data for the Wellbore Simulator mode in the Cementing module (OptiCem). This dialog allows you to enter and manage offshore, zone depth, and temperature information.

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Do not check this box because we are not taking returns at the sea floor.

Reservoir Zone and Fracture Zone are the same in this case.

Temperature can be defined in several ways. If the Bottom Hole Circulating Temperature is known, you can specify it. You can calculate the API BHCT based on mud outlet temperature and BHST. You can specify a profile based on depth. You can import a temperature profile from WellCat.

Define the temperature profile to be used or import a temperature profile.

Specifying Additional Analysis Parameters The Parameter > Analysis Data dialog provides supplemental control of several values before performing the Wellbore Simulator calculations. If Eccentricity is turned off, then the wellbore simulator performs its calculations assuming 100% standoff. If you want the eccentricity calculations at a particular standoff, select the Entered Standoff option on the Centralizer Placement Dialog. Otherwise, it will run with an actual standoff profile.

To ensure proper plug seating, additional pressure may be applied to the casing immediately after the plug is landed.

Erodibility is only available to Halliburton personnel. If you need this option, contact your local Zonal Isolation Group. Check Calculate Automatically for automatic calculation of step size. Usually you will want to check this box.

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Analyzing Results Results for the Cementing analysis are presented in plots, tables and a report. All results are available using the View menu.

What is the Circulating Pressure Throughout the Cement Job?

Use the View > Plot > Circ Pres and Den - Frac Zone plot to determine the circulating pressure fluid volume pumped at the fracture zone specified on Parameter > Additional Data. The circulating pressure during the displacement stage exceeds the fracture pressure. These lines indicate when the various stages occur.

Fracture pressure

The formation breakdown pressure at this depth is indicated by one of the curves on this plot. If the Automatic Rate Adjustment option was selected (on Parameter > Job Data), then a second curve indicates the safety factor. If the circulating pressure exceeds the fracture zone pressure, the fluid can fracture the formation and result in lost circulation from the wellbore. If the circulating pressure exceeds the fracture zone pressure, reduce the pump rates or turn on the Automatic Rate Adjustment option. If reducing the pump rates does not completely solve the problem, decrease the density of one or more fluids (with foamed fluids, or by

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increasing the nitrogen concentration), or decrease the volume of the heaviest stages. If you prefer, you can view this information as ECD versus volume pumped. Click the right mouse button anywhere on the plot to open the plot selection box. Highlight the plot you want displayed and click the left mouse button.

Observe the circulating density as a function of volume pumped.

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Is There Free Fall?

The View > Plot > Comparison of Rates In and Out plot displays the total annular return rate and corresponding pump rate versus the fluid pumped into the well. This data may be correlated with information in the Volume and Rates Calculations table in the Cementing Report. (View > Report) Differences between the two rate curves indicates free fall without nitrogen injection. If free fall occurs and the well goes on vacuum, the rate out will initially exceed, and then fall below, the planned pumped rate.

Notice that cement free fall does occur because rate out initially exceeds the rate in, but then falls below the pump rate in.

Notice the rate out initially exceeds the rate in.

After initial high, rate out then falls below rate in.

What is the Surface Pressure?

Use the View > Plot > Calculated Wellhead/Surface Pressure plot to view the pressure changes as varying density fluids are pumped at varying rates through the well. If the Surface Iron option was selected (on the Case > Cement Circulating System dialog) this graph is titled Calculated Surface Pressure. This data may be correlated with information in the Volume and Rates Calculations table on the cementing report. The calculated wellhead pressure is lower than pump pressure because of the hydrostatic head and friction in the lines between the pump and cementing head.

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A horizontal graph line along the x-axis indicates free fall. Often, as the majority of the cement moves from the casing to the annulus, the slope of this curve beings to increase. Usually, it continues to increase as the heavier cementing fluids are forced up the annular gap.

Free Fall indicated when pressure is constant.

Automatically Adjusting the Flowrate

Because the circulating pressure exceeds the fracture pressure using the rates specified on the Parameter > Job Data dialog, you can allow the

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software to automatically adjust the pump rates. Click the Automatic Rate Adjustment box on the Parameter > Job Data dialog. Click Automatic Rate Adjustment to have the rate adjusted to avoid exceeding the fracture pressure. If you allow automatic rate adjustment, you must specify a Safety Factor.

These rates will be adjusted.

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Using automatic rate adjustment, the maximum circulating pressure is less than the fracture pressure. Notice the safe pressure (based on safety factor) is indicated on the plot.

What Are the Adjusted Rates?

The View > Plot > Comparison of Rates In and Out plot displays the total annular return rate and corresponding pump rate versus the fluid pumped into the well. This data may be correlated with information in

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the Volume and Rates Calculations table in the Cementing Report. (View > Report) You can view the adjusted rates using this plot. Rates have been decreased to reduce the circulating pressure as a result of checking the Automatic Rate Adjustment box on the Parameter > Job Data dialog. Refer to the Job Data dialog to view the rates specified prior to the rate adjustment.

Using Foamed Cement

Using foamed cement is another means to reduce the circulating pressures. The Parameter > Foam Data dialog is available only if you check the Use Foam Schedule box on the Parameter > Job Data dialog while using the Wellbore Simulator analysis mode. This dialog lets you

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describe calculation methods and stages when simulating foam in a cement job. Select Constant or Staged Gas Flow to keep the nitrogen constant for a segment.The foam density will follow the pressure gradient, and thus decreases from the bottom to the top of the segment. The longer the segment, the greater the density variance.

Type concentrations for Surfactant, Stabilizer.

Select this option if the nitrogen ratio will be adjusted to offset pressure changes and thus hold density more constant. Use this option only with automated nitrogen pumping equipment.

Click the stage you want to define using the bottom portion of this dialog.

This information is read-only. It is defaulted from the Job Data dialog. The Gas Rate Stage Number is used to tell how many different gas rates are to be used under the Stage Gas option and where each of the rates are used.

In order to foam a segment, you must check the Foam box.

Enter Foam Density and Quality (the volume percentage of gas in the foam) is calculated. or

Enter Quality (the volume percentage of gas in the foam) and Foam Density is calculated.

Using the Foam Schedule

Use View > Foam Schedule dialog to calculate and view the Foam Pumping Schedule. This dialog lists liquid volume and gas rates of the fluids left in the annulus at the end of the simulation. The calculated hydrostatic pressure for the frac zone and reservoir zones are displayed at the bottom of the table. The frac zone and reservoir zones are specified using the Parameter > Additional Data dialog.

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Notice that some of these fluids may not be foamed. Some fluids may not appear in this report if they were pumped completely out of the annulus. If an error occurs during the calculation process, an error dialog appears displaying a description of the error. When you finish reading it, click OK. The Error dialog and the Calculate dialog close so you can begin working on solving the source of the error.

These are design depths (as specified on the Job Data dialog) and may not be the actual depths. Review the View > Final Density and Hydrostatic plot for accurate cement locations. Click Calculate to ensure you are looking at accurate results.

Adjusted Liquid Volume and Adjusted Gas Rate sliders adjust the cement tops or placement.

These are the calculated hydrostatic pressure gradients for the depths of interest specified on the Additional Data dialog.

Final Gas Rate and Adjusted Final Gas Rate do not apply when you are using constant or stage gas flow.

To check results of the foam schedule calculation: 1) Check the Fluid Animations Schematic to see whether the desired top of cement was achieved, check the Final Positions of Stages table in the reports, or downhole density plot. 2) Check the circulation Pressure and Density-Fracture Zone graph and the Circulation Pressure and Density-Reservoir Zone graphs to see if the density is acceptable. 3) Adjust, rerun, and recheck the job as follows:

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Checking Results If TOC is....

and ECD is....

then do this:

Low

Light

1. Increase density or decrease quality. 2. Rerun the Foam Schedule. 3. Use the slider bar (top of Foam Data dialog) to increase the Adjusted Liquid Volume. 4. Click the Calculate button. 5. Check the Fluid Animation Schematic and the Circ Pres and Den plots.

Low

Acceptable

1. Use the slider bar (top of Foam Data dialog) to increase the Adjusted Liquid Volume. 2. Repeat steps 4 and 5 above.

Low

Heavy

1. Use the slider bar (top of Foam Data dialog) to increase the Adjusted Gas Rate. 2. Repeat steps 4 and 5 above.

Low

Light

1. Increase the density or decrease quality. 2. Rerun the Foam Schedule. 3. Repeat steps 4 and 5 above.

Acceptable

Acceptable

Do nothing.

Acceptable

Heavy

1. Decrease density or increase quality. 2. Rerun the Foam Schedule. 3. Repeat steps 4 and 5 above.

Acceptable

Heavy

1. Decrease density or increase quality. 2. Rerun the Foam Simulator. 3. Repeat steps 4 and 5 above.

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Checking Results (Continued) High**

Light

1. Manually decrease N2 in the Adjusted Start Gas Rate column. 2. If calculation method is constant density, also manually decrease N2 in the Adj. Final Gas Rate column. 3. Repeat steps 4 and 5 above.

High**

Acceptable

1. Manually decrease liquid volume in the Adj. Liq. Vol. column.* 2. Repeat steps 4 and 5 above.

High**

Heavy

1. Decrease density or increase quality. 2. Rerun the Foam Simulator. 3. Repeat steps 4 and 5 above.

* To estimate the percentage by which to change the volume, use the percentage by which the simulated foamed length differs from the desired length. (If the foamed length 1,500 feet and the desired length is 2,000 feet, increase by 33%.) ** This scenario is unlikely because the Fluid Placement calculations should prevent excessive top of cement. Repeat these steps until you are satisfied with the results. Round the slurry and gas rate quantities before running the Wellbore Simulator.

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References Ravi, K.M., and Sutton, D.L., “New Rheological Correlation for Cement Slurries as a Function of Temperature,” SPE 20449. Shah, Subhash, N., and Sutton, David, L., “New Friction Correlation for Cements from Pipe And Rotational-Viscometer Data,” SPE 19539.

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Chapter 11

Critical Speed Critical Speed Course Overview The Critical Speed Analysis module assists with the determination and prediction of critical rotation speeds that may results in damaging downhole vibrations. The analysis begins with a static structural analysis to determine where the drillstring is in contact with the wellbore and to determine what forces are acting on the drillstring. The next step is the vibrational analysis. The program predicts the relative stresses the drillstring will be subjected to based upon a range of rotational speeds (RPMs) input by the user. During the Critical Speed segment of your WELLPLAN training you will learn the basic functionality of the Critical Speed Analysis module. The class exercises are designed to mimic a typical Critical Speed Analysis workflow. In the future, you can refer to these workflows to assist you with using WELLPLAN. By the end of the Critical Speed course you will know how to complete the following tasks: Input required data for the analysis. Create analysis plots. Predict critical rotational speeds that may cause damaging vibrations. Investigate the effect of changing input parameters on the vibrational response of the string. Recognize drilling parameters that are likely to cause vibration.

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Chapter 11: Critical Speed

Workflow The following steps are designed to be a general guide to the steps involved in using the Critical Speed Analysis module. This workflow is not intended to suggest that you must follow these steps when using the module. There are certainly other workflows that may meet your analysis requirements. Open a Case using the Well Explorer. Refer to “Using the Well Explorer” on page 55 for instructions on using the Well Explorer. Select the Critical Speed Analysis module by clicking

.

Define the wellbore. (Case > Hole Section) Define the workstring. Use the same dialog to define all workstrings (drillstrings, tubing, liners, and so forth) (Case > String Editor) Enter wellpath data. (Case > Wellpath > Editor) Define the fluids used. You can define as many fluids as you want. Only one fluid can be used at a time. (Case > Fluid Editor) Define the analysis parameters. (Parameter > Analysis Parameters) Optional: You may want to change the boundary conditions. This is not normally recommended. (Parameter > Boundary Conditions) Optional: You may want to change the mesh zone. This is not normally recommended. (Parameter > Mesh Zone) Analyze the results. First, determine the critical rotational speeds. (View > Rotational Speed Plots > Resultant Stresses) Next, determine where in the string the greatest relative stress is occurring at the critical rotational speeds. (View > Position Plots > Resultant Stresses) You may also want to determine what type of stress is causing the large relative stresses. (View > Position Plots > Stress Components)

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Introducing Critical Speed Analysis What is the Critical Speed Module? The Critical Speed Analysis module is used to identify critical rotary speeds and areas of high stress concentration in the drillstring. The analysis uses an engineering analysis technique called Forced Frequency Response (FFR) to solve for resonant rotational speeds (RPMs). The Critical Speed Analysis module is based on a nonlinear finite element solution written to include intermittent contact/friction, finite displacement, buoyancy and other effects that occur while drilling. Refer to “Vibrational Analysis” on page 491 for more information. The Critical Speed Analysis module is designed to analyze the 3D lateral bending vibrational responses of a bottom hole assembly. The analysis can model axial vibrations (vibrations parallel to the drillstring axis), lateral vibrations (perpendicular to the drillstring axis) and torsional (twist) vibrations. The Critical Speed Analysis module includes damping and mass effects in order to more accurately represent the downhole environment. Refer to “Mass Matrix” on page 494 and “Damping Matrix” on page 494 for more information.

Why Use the Critical Speed Module? All drillstrings have natural axial, lateral, and torsional modes of vibration. This vibration is at a natural frequency that depends on many drillstring parameters, including geometry, material properties, weight, and length. In the downhole environment, a drillstring is subjected to forced vibrations or excitations. Excitations can be in the form of displacements or contact forces at the bit, stabilizers, or along the string. The Critical Speed Analysis module models excitations using displacements instead of contact forces. A well known and documented excitation is due to the tricone drill bit rolling over high and low spots in the formation. This type of excitation produces primarily axial bit displacements having frequencies of three cycles per revolution. Another source of excitation can result from stabilizers rubbing against the wellbore. When stabilizers contact the wellbore, frictional forces develop as a result of the contact and rotation and can produce

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vibrations. Refer to “Excitation Factors” on page 495 for more information. Resonance can occur when a drillstring’s natural vibration is subjected to a forced vibration. Resonance is an increase in amplitude that results when a drillstring is exposed to a periodic force or displacement (excitation) whose frequency is equal to, or very close to the natural frequency of the system. Resonance is nearly always accompanied with severe high dynamic stresses that can cause drillstring damage or failure. The Critical Speed Analysis module indicates resonant frequencies for a drillstring rotating in a wellbore, as well as nonrotating steerable assemblies. The effects of hole angle, curvature, collar size, contact locations, and BHA displacement due to rotational friction effects can be modeled. Drill string rotation will affect the results of this analysis, to some degree, due to additional torque at the contact points that are generated due to friction forces.

Critical Speed Limitations A rotating drillstring is subject to intermittent contact, impact, and friction effects as well as many other highly nonlinear and transient phenomena. Since the Critical Speed Analysis module assumes cyclic behavior, transient effects typical for drillstring dynamics cannot be modeled. The analysis assumes all drillstring components are free of stress fractures. Ideally, this type of analysis is run along with downhole sensors, or at the least with careful surface observations. Isolating and identifying the principal excitation mechanism responsible for drillstring vibrations has proven to be challenging. The literature contains many studies undertaken to acquire and analyze experimental and field-derived data to determine the dynamic characteristics of drillstring systems. Many excitation mechanisms have been identified, including bit forces, stabilizer forces, mass imbalances, and walk and whirl mechanisms. It is important to realize that the Critical Speed Analysis module does not provide an exact solution for critical frequencies. The results from the Critical Speed Analysis are relative stresses, indicating those frequencies that are likely to cause damaging vibrations. The Critical Speed Analysis module can be used prior to drilling, or can be use in conjunction with downhole sensors. Vibration control is a multi-step process. It involves planning and analysis, monitoring during drilling, and interpreting control through observations.

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Using Critical Speed A typical critical speed analysis consists of an initial “frequency sweep,” in which the drillstring is analyzed over a user-specified range of operating speeds. The program repeatedly analyzes the drillstring by incrementally stepping though the given range. At each step the program computes the excitation frequency for that step from the current rotational speed (RPM) and the excitation factor. It then applies the excitation to the drillstring at the computed frequency and solves for the response in the entire model. For this analysis, response means any component of displacement, force, or stress. The maximum response at each step is saved. After the entire range has been analyzed, the maximums can be plotted against the operating speed range. These plots are then used to determine the critical operating speeds for the drillstring or assembly. Once the critical speeds are determined, the analysis can be repeated at each critical speed and the response of the total drillstring model can be examined. This type of analysis is used to determine the exact nature of the resonant behavior at a particular critical speed.

Starting the Critical Speed Module There are two ways to begin the Critical Speed Analysis module:

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Select Critical Speed from the Modules menu.

z

Click the

button.

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Choose Critical Speed Analysis from Module menu, or by clicking the Critical Speed Module button.

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Determining Critical Rotational Speeds Defining Analysis Parameters Use the Parameter > Analysis Parameters dialog to input parameters needed to perform the critical speed calculations.

Type the rate you want the forcing function to be applied (number of excitation per revolution). A general rule of thumb is to use 3.0 for tricone bits and 6.0 to 9.0 for PDC bits. The nature of forcing functions is still an area of study in the industry. Refer to “Excitation Factors” on page 495 for more information.

Normally, you will type values of 0.0 (zero) and 99999.9 for the Mesh Begins At Depth From Bit and Max Total Length of Mesh, respectively, in order to analyze the entire string starting at the bit (or as much as can be meshed by the number of nodes available). If you want to study an limited portion of the string, type a smaller range. Use measured depth to estimate the distance in feet.If you get an error message indicating an “Non Converged Solution,” this means the critical speed analysis was unable to solve the structural solution, usually because the of a complex drillstring (many small components) and hole geometry. If this happens, shorten the mesh length, and run the analysis again.

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Type the actual torque at the bit. Obtain typical bit torque values from the bit manufacturer, or provide an estimate based on your own experience.

Check this box to turn on the calculation of the nodal torque due to friction. The nodal torque affects the initial static solution of the displaced shape of the BHA. If you don’t check this box, the only torque that will be used is the torque you entered for Torque at Bit.

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Specifying the Boundary Conditions Use the Parameter > Boundary Condition dialog to determine the physical constraints on the top and bottom nodes of the mesh. Note: Using Default Boundary Conditions is Advised...

Use the default values as presented here, unless you are familiar with Finite Element Analysis methods.

Fix w/Axial Slider prevents all movement except for sliding movement along the longitudinal axis of the string.

Fix Axial prevents sliding movement along the longitudinal axis of the string, but allows all other types of movement.

Specifying the Mesh Zone Use the Parameter > Mesh Zone dialog to alter the default values for the mesh zones in special situations. You may consider changing the mesh if you are particularly interested in what is happening at a particular section of the workstring. Otherwise, the defaults provide adequate analysis of most situations. Refer to “Defining the Finite Element Mesh” on page 525 for more information.

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Analyzing the Results All critical speed analysis results are presented as graphs, and can be selected from the View menu. Calculations will be performed automatically when you select a plot from the View menu.

What are the Critical Rotational Speeds?

You can determine the critical rotational speeds by reviewing the Equivalent Resultant Stress curve on the View > Rotational Speed Plots > Resultant Stresses plot. The peaks indicate a critical rotational frequency at certain rotational speeds. You should avoid the rotational speeds associated with a large relative stress. This frequency should be analyzed further. Note that you cannot determine the actual resultant stress by reviewing this plot. You can only determine that the stresses at the peaks are greater than the stresses at other rpms.

What are Relative Stresses....

It is important to remember that the stress values are relative stresses and not actual stresses. The stresses are relative in magnitude to each other also. You cannot determine from the plot what the actual stress is. You can only compare relative magnitudes.

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For example:

If two stresses are calculated to be 5,000 and 10,000 psi, the stresses may not be exactly equal to the calculated value. Because the stresses are relative in magnitude, the stresses may really be 4,000 and 8,000 psi. All peaks represent stresses above and beyond steady state stresses caused by vibrations. They are relative to the magnitude of the forcing function used and should be used only to assist with the location of critical rotating speeds. The forcing function is a periodic displacement or force (the Critical Speed Analysis module uses displacement) at a point on the drillstring that is assumed to occur a regular number of times per revolution. The forcing function (displacement) can be lateral, axial, or torsional.

Non-Converged Solutions

Notice there is not data to display in the following plot. The Status Message indicates there is a “Non-Converged Solution”. A “nonconverged” solution sometimes occurs when the length of the mesh is too long and a solution can’t be calculated.

Status Message indicates a problem calculating the solution.

What To Do When The Solution Doesn’t Converge z

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Change the length of the mesh: Refer to “Defining Analysis Parameters” on page 483 for more information on using this dialog. Refer to “Supporting Information and Calculations” on page 491 in this chapter, and “Supporting Information and Calculations” on

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page 525 in the Bottom Hole Assembly Analysis chapter in this manual for more information on finite element analysis and the implementation in WELLPLAN. The defaults values of 0 for Mesh Begins at Dist From Bit and 99999 for Max Total Length of Mesh will mesh the entire length of the drillstring from the bit because the 0 entered for Mesh Begins at Dist From Bit indicates the mesh begins at the bit and the 99999 entered for Max total Length of Mesh. Because no drillstring is longer than 99999, the interval beginning at 0 and ending at 99999 includes the entire string. Assume your string is 15,000ft long. To mesh (analyze) the entire length of the drillstring, you could specify that the Max total Length of Mesh is 15,000 (rather than the default 99999) because 15,000 is the length of the string. If the solution does not converge, you must shorten the length of the mesh by typing a smaller value into the Max total Length of Mesh field. You may consider reducing the value in this field in 1,000 ft intervals until the results converge. i.e. specify 14,000ft for Max total Length of Mesh. If the solution doesn't converge, try 13,000ft and so on. z

Simplify the string: Because the finite element analysis places nodes at the points in the string where the components change, you may consider simplifying the string by removing smaller components or by combining components in order to reduce the number of nodes. Exercise caution when simplifying the string in this manner to ensure you do not change the string design significantly or the analysis may not reflect a true analysis of your string.

z

Change the mesh zone: If you are knowledgeable about finite element analysis, you may consider changing the mesh zone as described on page 484.

Where in the BHA are the Large Relative Stresses Occurring?

Now that you know what rotational speeds are causing large relative stresses, you may want to know where in the bottom hole assembly (BHA) these stresses are occurring. Use the View > Position Plots >

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Resultant Stresses plot to determine where in the BHA the large stresses are occurring. At 110 rpm, the maximum equivalent stress is acting on the bottom hole assembly 31 feet from the bit. Refer to Case > String Editor to determine what component is at the specified distance from the bit.

Use the slider bar to change the rotational speed you want to analyze.

What Kind of Stress is Causing the Large Relative Stress?

You may want to know what type of stress (axial, bending, torsional, shear) is causing the large relative resultant stresses to occur in a certain

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part of the BHA. Use the View > Position Plots > Stress Components plot. Bending stress is the most significant stress acting on the bottom hole assembly 31 feet from the bit while rotating at 110 rpm.

How Do I View the Large Relative Stress at Any Position on One Plot?

We used one plot to tell us what rotational speeds have a large relative stress and then referred to a position plot to tell us where in the bottom hole assembly these stresses were occurring. You can use the View > 3D

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Plots > Resultant Stresses > Equivalent plot to view this information on one plot if you prefer.

Click and hold down the left mouse button anywhere on the plot and then move the mouse to rotate the plot.

Read Distance from Bit on this axis.

Read Rotational Speed on this axis. The peaks correspond to the critical rotational speeds.

Read the Equivalent Stress on this axis.

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Supporting Information and Calculations Structural Solution The Critical Speed Analysis module begins by performing a structural solution to determine the displaced shape of the drillstring and the forces acting on it. The structural solution is accomplished through the use of the mathematical Finite Element Analysis method. The static structural solution is completed to determine where the drillstring is in contact with the wellbore. This information is passed on to the vibrational analysis segment of the analysis. Any contact points found during the structural solution are assumed to remain in contact during the vibrational analysis. Other points of contact between the string and the wellbore may occur due to vibration. These contact points may lead to displacements outside of the wellbore. In reality, displacements outside of the wellbore do not occur. This is a limitation in the analysis. As a result of this limitation, the analysis predicts a relative critical frequency (RPM), and does not model or predict the actual magnitude of a critical frequency. The steps performed in the structural solution analysis step are the same as those performed in the WELLPLAN Bottom Hole Assembly analysis module. The only exception is that the Critical Speed Analysis module meshes the drillstring into 150 nodes. (The Bottom Hole Assembly Analysis module will mesh the BHA into 40 nodes.) Refer to the Bottom Hole Assembly module chapter in this manual for more details concerning the structural solution.

Vibrational Analysis Following the completion of the structural solution, the vibrational portion of the analysis is begun. After the shape of the drillstring is determined and the structural solution has been performed, the Critical Speed Analysis module calculates the critical frequencies, or RPMs. The critical frequencies are determined from the response of the BHA to some user specified harmonic excitation usually, but not limited, to the bit. The Critical Speed Analysis module assumes that at a critical rotational speed, or RPM, excitations at the bit, stabilizer, or other contact points cause large displacements and stresses elsewhere in the drillstring. Because the Critical Speed Analysis module is a harmonic

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vibration analysis, it does not model the reaction of the drillstring if it is rotating about an axis that is not centered on the drillstring axis (bit whirl). The Critical Speed Analysis module solves for a range of frequencies to determine the sensitivity of the BHA to the excitation frequency. Because the analysis applies the boundary conditions only during the static structural solution, it may yield displacements outside of the wellbore during the vibrational analysis. The Critical Speed Analysis module is not a transient analysis, and does not solve the analysis related to time. As a result, any contact points occurring as a result of the vibrational analysis are allowed to penetrate the wellbore. The full transient dynamic response analysis of any non-linear finite element model involves the finite integration of the equations of motion found in Equation 1. In Equation 1, P(t) is a vector quantity indicating the periodic displacement at a point on the drillstring that occurs at a regular number of times per revolution. This displacement (or force) can be lateral, axial, or torsional. {P(t)} = {I(u,t)} + [C]{ú(t)} + [M]{Ü(t)} (equation 1) where: {P(t)} = {u(t)} = {I(u,t)}= [C] = [M] = {} [] ()

Applied Load Vector (or forcing function) at time t Displacement Vector at time t Internal Force Vector at time t and Displacement State {u} Damping Matrix Mass Matrix indicates a vector quantity indicates a matrix quantity indicates differentiation with respect to time t

To utilize this equation for solving drilling mechanics problems, it must be formulated to include the following factors common to drilling. • • • •

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The need for large displacement and finite rotation beam theories in modeling drillstring and BHA components Dealing with intermittent contact and the friction effects involved The need to model a tortuous 3D curved wellbore surface Representing the structural behavior of certain drillstring components (motors and so forth)

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The approach utilized in the analysis solves a linearized form of the above equation for the case of vibration in which all displacements and forces are varying harmonically in time at the same frequency. In order to develop the harmonic formula, two assumptions are made: • •

First, it is assumed that the response is at the same frequency as the excitation, but not necessarily the same phase. Second, it is assumed that the excitation is a function and response of the sin and cosine terms at the same phase. Since the analysis assumes cyclic behavior, transient effects, such as impact forces that may have a significant impact on the service life of a component, can not be modeled with the Critical Speed module.

The solution is based upon an imposed load or force vector excitation {P}, and it is assumed the BHA is subjected to a harmonically varying form of the excitation {P} given by: {P(t)} = {Ps}sin ωt + {Pc}cos ωt (equation 2) which yields a resulting steady state displacement response of: {u(t)} = {us} sin ωt + {uc} cos ωt (equation 3) The angular frequency (ω) of the excitation is directly related to the rotary speed through the use of an excitation factor. The excitation factor designates how many times per revolution a given excitation occurs. Combining the three previous equations and implementing concepts from complex vector algebra, it is apparent that the steady state displacement field arising from the applied harmonic loading can be determined by solving for the solution of the linearized system of complex force-displacement relation given by: {Pc} + i{Ps} = ([J] - ω2[M] + iω[C])({uc} + i{us}) (equation 4) where: i [J] [M] [C]

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During the vibration portion of the analysis, the previous equation is solved for a range of operating (RPM) speeds. At a critical rotary speed, small forced excitations at the point of application will cause large displacements and stresses elsewhere in the drillstring. Therefore, ωcr is said to locate a point of structural instability of the BHA. The Critical Speed Analysis module generates many graphics to illustrate this phenomena.

Mass Matrix The mass matrix implemented in the Critical Speed Analysis module is a lumped mass matrix. From the composition of the matrices, it is evident that the material component descriptions (ID, OD, weight, material), and fluid descriptions are important data for correctly determining vibrational response. In the previous equation, the mass matrix is denoted by [M], and contains terms based on the following four classes of effects: z

Structural - This is the primary mass matrix, and is based on the dimensions and material of the drillstring.

z

Fluid - Additional term included to account for the weight of the fluid inside the drillstring.

z

Inertial - Includes the effects of acceleration of mud outside the drillstring.

z

Nonstructural mass - Includes miscellaneous masses that may be attached to the drillstring and are not accounted for in any other way.

Damping Matrix The Critical Speed Analysis module includes damping in predicting the response of the drillstring to the specified excitations. Damping primarily limits the magnitude of the response to the excitation. An important implication of including damping in the model is that while the response of the BHA will be at the same frequency as the excitation, it may not be in phase with it. Damping includes the effects of interaction with the formation, drilling fluid effects, inertial effects of acceleration of mud outside the drillstring and mass damping produced by the BHA structure.

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To account for the damping, or energy losses that drillstring vibration is subjected to, the Critical Speed includes the following three damping mechanisms. z

Structural Damping - Accounts for energy losses due to mechanical means.

z

Fluid Damping - Accounts for energy losses due to fluid movement on the drillstring. This damping does not use fluid viscosity, and applies to the axial and torsional directions only.

z

Lateral Fluid Damping - Accounts for energy losses due to viscous fluid damping, and is applied to lateral direction only. This type of damping is based on the work done by Chen (refer to the Reference section) and uses flow equations for fluid moving around a cylinder in a confined space.

The damping matrix terms are a function of beam element length, outer diameter, and constant fluid damping coefficients. Discrete fluid damping coefficients are also assigned for lateral, axial, and torsional DOF. All damping coefficients are defaulted and are not user input items. Including damping is an important part of the vibrational analysis. Referring to Equation 4, if the damping matrix is removed, the equation is simplified. However, if damping is not included, the plots of amplitude vs. frequency cause the critical states to appear as extremely steep and relatively narrow spikes of infinite amplitude. A steep, narrow spike could mislead a user into concluding that the analysis calculates an exact value for the critical frequency (RPM). In reality, the analysis can only predict a range of critical frequencies, but can not provide an exact critical frequency.

Excitation Factors The frequency of the excitation mechanism is designated by the use of the excitation factor. This factor is simply the number of times the excitation is applied for each revolution of the drillstring. Although excitations are usually at the bit, this analysis can model excitations at other locations. The Critical Speed Analysis module can also model multiple excitations at multiple locations. These excitations can be out of phase with one another, but they will all be assumed to be excited at the same number of excitations per revolution. This can be a

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problem if a tricone bit (normally 3 excitations/revolution) is combined with a four blade stabilizer (perhaps 4 excitations/revolution). Experience has shown the following excitation factors: z

Tricone Bits: EF = 3, as expected from the three lobed geometry

z

PDC Bits: EF for PDC Bits vary depending on the bit design. There is no specific rule for selecting the EF for PDC bits. However a general rule obtained from laboratory experience is:

EF= (n)(#Blades) + 1; where n = 1 or 2

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The following table presents several primary and secondary excitation factors that may occur during drilling. For more information concerning this information, refer to the references presented at the end of this chapter. Physical Mechanism

Primary Excitation(s)

Secondary Excitation(s)

Mass Imbalance or Bent Pipe

1 X RPM Lateral

2 X RPM Axial or 2 X RPM Torsional or 2 X RPM Lateral

Misalignment

Tricone Bit

1 X RPM Lateral or

2 X RPM Axial or

2 X RPM Lateral

2 X RPM Axial

3 X RPM Axial

3 X RPM Torsional or 3/2 X RPM Lateral

Very Soft Formation, Low WOB, Causing a Loose Drillstring

1,2,3,4,5, X RPM Axial, Torsional, Lateral

Rotational Walk (precessional)

dh /(dh - dd) X RPM Lateral

2(dh (dh -dd)) RPM Axial or 2(dh (dh -dd)) RPM Torsional

Rotational Walk (backward whirl)

dd /(dh - dd) X RPM Lateral

2(dd (dh -dd)) RPM Axial or 2(dd (dh -dd)) RPM Torsional

Non synchronous Walk or Whirl

Drillstring Whip

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(0.8 to 1.0)(dh(dh - dd)) X RPM Lateral (0.6 to 2.0)(dh(dh - dd)) X RPM

(0.6 to 2.0)(dh(dh - dd)) X RPM Axial or

RPM Harmonics (1X, 2X, 3X) Lateral

RPM Harmonics Axial, Torsional

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References Field, D.J., DRD Corp., Swarbrick, A.J., Halliburton MWD, and Haduch, G.A., DRD Corp., “Techniques for Successful Application of Dynamic Analysis in the Prevention of Field-Induced Vibration Damage in MWD Tools,” SPE #25773, 1993. Apostal, M.C., Haduch, G.A., and Williams, J.B., DRD Corp., “A Study to Determine the Effect of Damping on Finite-Element-Based, ForcedFrequency-Response Models for Bottomhole Assemble Vibration Analysis”, SPE #20458, 1990. Besaisow, A.A. and Payne, M.L., ARCO Oil and Gas Co., “A Study of Excitation Mechanisms and Resonances Inducing BHA Vibrations”, SPE #15560, 1986. Nicholson, J.W., Shell Research B.V., “An Integrated Approach to Drilling Dynamics Planning, Identification, and Control”, IADC/SPE #27537, 1994. Defourny, P., Security DBS, and Abbassian, F., BP Exploration, “Flexible Bit: A New Anti-Vibration PDC Bit Concept”, SPE #30475, 1995. Gallagher, J., Baker Hughes INTEQ, Waller, M., Shell (U.K.) E&P, and Ruszka, J., Baker Hughes INTEQ, “Performance Drilling: A Practical Solution to Drillstring Vibration”, IADC/SPE 27538, 1994. Behr, S.M., Warren, T.M., Sinor, L.A., Brett, J.F., Amoco Production Co., “Three-Dimensional Modeling of PDC Bits”, SPE #21928, 1991. Behr, S.M., Warren, T.M., Brett, J.F., Amoco Production Co., “Bit Whirl: A New Theory of PDC Bit Failure”, SPE 19571, 1989. Dykstra, M.W.; Chen, D. C-K.; Warren, T.M.; Azar, J.J., “Drillstring Component Mass Imbalance: A Major Source of Downhole Vibrations”, SPE #29350, 1996.

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Chapter 12

Bottom Hole Assembly Overview The Bottom Hole Assembly module predicts the directional drilling performance of a bottom hole assembly. The module provides an accurate representation of the forces acting on the assembly as it lies in the wellbore. This analysis can be useful for explaining unexpected performance or for determining the causes of tool failures. In addition, the module can solve a “drillahead” scenario representing the expected behavior of the bottom hole assembly as it drills new hole. During the Bottom Hole Assembly segment of your WELLPLAN training you will learn the basic functionality of the Bottom Hole Assembly module. The exercises are designed to follow a typical workflow using the module. In the future, you can refer to these workflows to assist you with using WELLPLAN. First we are going to analyze the current position of the bottom hole assembly. We will investigate the position of the bottom hole assembly in the wellbore and we will determine the side forces acting on the bottom hole assembly where it is in contact with the wellbore. Later we will analyze the bottom hole assembly as it drills ahead. By the end of the Bottom Hole Assembly course you will know how to: Input required data. Create analysis plots and report. Analyze plots to predict string behavior over a range of operating parameters. Analyze a static bottom hole assembly. Predict how an assembly will drill ahead.

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Chapter 12: Bottom Hole Assembly

Workflow The following steps are designed to be a general guide for using the Bottom Hole Assembly module. This workflow is not intended to suggest that you must follow these steps when using the module. There are other workflows that may meet your analysis requirements. Open a Case using the Well Explorer. Refer to “Using the Well Explorer” on page 55 for instructions on using the Well Explorer. Select the Bottom Hole Assembly module by clicking

.

Define the wellbore. (Case > Hole Section) Define the workstring. (Case > String Editor) Enter wellpath data. (Case > Wellpath > Editor) Define the fluids used. (Case > Fluid Editor) Define the analysis parameters. (Parameter > Analysis), and specify the temperature. You can define as many fluids as you want. Only one fluid can be used at a time. (Case > Fluid Editor) Optional: You may want to change the mesh zone. This is not normally recommended. (Parameter > Mesh Zone) Analyze the results using the Quick Look section of the Parameter > Analysis dialog or by using the more detailed View > Report > BHA. You can analyze the expected build/drop and walk rates for the bottom hole assembly. You can also analyze the contact forces acting on the BHA, which may assist you with determining why the bottom hole assembly is performing as it is.

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Introducing Bottom Hole Assembly Analysis What is the Bottom Hole Assembly Module? The Bottom Hole Assembly module analyzes a bottom hole assembly (BHA) in a static “in-place” condition or in a “drillahead” mode. Many different factors influence the behavior of a bottom hole assembly. These factors include more controllable parameters such as WOB, and drillstring component size and placement, as well as less controllable items such as formation type. Because the performance of a bottom hole assembly is impacted by such a wide and varied range of parameters, predicting the behavior of a bottom hole assembly can be very complex. Engineers in other fields have often relied on the Finite Element Analysis Method to solve complex problems. The Finite Element Analysis (FEA) method solves a complex problem by breaking it into smaller problems. Each of the smaller problems can then be solved much easier. The individual solutions to the smaller problems can be combined to solve the complex problem. Depending on the number of elements (smaller problems) that the complex structure (overall problem) is comprised of, the solution can become very laborious. Fortunately, the combination of the increasing speed of computing power and creative mathematics have significantly simplified FEA analysis. Refer to “Three Fundamental Requirements of Structural Analysis” on page 525 for more information. Because a bottom hole assembly is composed of many different elements of varying dimensions, it lends itself quite well to the FEA method. The following sections describe the major steps performed by the Bottom Hole Assembly module while solving for an “in-place” solution, as well as a “drillahead” prediction. For more technical information, refer to “Supporting Information and Calculations” on page 525.

Why Should I Use the Bottom Hole Assembly Module? There are many times where the Bottom Hole Assembly module can be useful. Among these are: z

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Chapter 12: Bottom Hole Assembly z

Study previous directional failures through analysis of contact forces on tools.

z

Predict the directional behavior (including build, walk, and drop) of a bottom hole assembly as it drills ahead through a specified interval.

z

Predict the transient effect when new assembly is run in hole.

z

Adjust operating parameters to affect bottom hole assembly performance.

z

Study effects of bent assemblies, collar size, stabilizer placement, eccentric stabilizers, stabilizer wear, hole enlargement, operating parameters for optimal performance.

z

Select proper bent sub to achieve desired build or drop rate.

z

Estimate the additional torque drawn from a motor due to lateral forces at bit.

z

Determine the downhole mechanism controlling the bottom hole assembly.

z

Determine the orientation of a bottomhole assembly (0 - 180 degrees left or right of high side) for achieving optimum performance in a well deflection scenario.

z

Compare a rotary versus steerable assembly performance for a given well trajectory analysis.

z

Optimize the design of a steerable system through modeling of number of bends and eccentric contact points in the bottom hole assembly.

Bottom Hole Assembly Module Limitations The Bottom Hole Assembly module does not model formation dip.

Starting Bottom Hole Assembly Analysis There are two ways to begin the Bottom Hole Assembly module: z

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Select Bottom Hole Assembly from the Modules menu.

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Click the Bottom Hole Assembly Analysis button

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Choose Bottom Hole Assembly Analysis from Module menu, or by clicking the Bottom Hole Assembly Analysis Module button.

Select analysis mode from submenu, or from Mode drop-down list.

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Analyzing a Static Bottom Hole Assembly Static in-place analysis of the bottom hole assembly is used to determine the contact forces and displaced shape of a bottom hole assembly, including bit tilt, side forces, and wellbore contact points.

Defining Analysis Parameters for Static Analysis Use Parameter > Analysis to input parameters needed to perform the calculations. Check to turn on the calculation of the nodal torque due to friction. The nodal torque affects the initial static solution of the displaced shape of the bottom hole assembly. If you do not check this box, the only torque that will be applied to the string is the specified torque at bit. Check this box to solve a “drillahead” scenario to represent the expected behavior of the bottom hole assembly as it drills new hole.

An analysis summary is presented in the Quick Look section. Other results are available using the View menu.

For more information regarding data required for this dialog, refer to the online help.

7

Drillahead Solution

Check the Enable Drillahead box to solve a “drillahead” scenario to represent the expected behavior of the bottom hole assembly as it drills new hole. The “drillahead” solution advances the bit depth, in 5-foot intervals, through the drill interval specified below. At each

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of the 5-foot intervals, a static solution is performed. The drillahead solution assumes the following: • The bit will drill in the direction it is pointed. • The bit will cut sideways due to the presence of side forces generated in the inclination and direction axes. • The formation has isotropic rock properties.

Specifying the Mesh Zone Use the Parameter > Mesh Zone dialog to alter the default values for the mesh zones in special situations. You may consider changing the mesh if you are particularly interested in what is happening at a particular section of the workstring. Otherwise, the defaults provide adequate analysis of most situations. Refer to “Defining the Finite Element Mesh” on page 525 for more information.

Analyzing Results for the Static (in-place) Position Using the Quick Look Section of the BHA Analysis Data Dialog

Information in the Quick Look section describe what is happening at the bit in the inclination and direction planes as well as build and walk rates. The inclination plane is the vertical plane. The direction plane is rotated 90 degrees to the vertical plane. A positive (+) value indicates the force is acting in a up or right direction while a negative (-) value indicates the force is acting in a down or left direction.

Inclination

Refer to “Bit Tilt and Resultant Side Force” on page 535 for an illustration and more description of the inclination angles and forces.

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Wellbore

This angle indicates the inclination of the wellbore relative to the vertical plane. String

This angle indicates the inclination of the string or the bit face relative to the vertical plane. Tilt

This angle indicates the bit tilt. Force

This indicates the magnitude of the force in the inclination plane acting perpendicular to the bit.

Direction

Refer to “Bit Tilt and Resultant Side Force” on page 535 for an illustration and more description of the direction angles and forces. Wellbore

This angle indicates the direction of the wellbore relative to the direction plane. String

This angle indicates the direction of the string or the bit face relative to the direction plane. Tilt

This angle indicates the bit tilt (in the direction plane). Force

This indicates the magnitude of the force in the direction plane acting perpendicular to the bit. This force is FD in the above figure.

Rates Build Rate

The build rate is the average expected build rate over the entire drillahead interval. Walk Rate

The walk rate is the average expected walk rate over the entire drillahead interval.

Weight on Bit Slider

Use the slider bar to vary the weight on bit. The results in the Quick Look section will be updated automatically as the weight on bit changes.

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Using Plots

Two plots are available for analysis. The View > Plot > Displacement plot allows you to determine how the bottom hole assembly is lying in the wellbore. The View > Plot > Side Force plot tells you the side force acting on the bottom hole assembly as it lies in the wellbore.

Displacement Plot

The View > Plot > Displacement plot displays the displacement from the centerline versus measured depth. Three measures of displacement are used. In all measurements, positive results are to the right or highside of the wellbore. Negative results are to the left or low-side of the wellbore. • • •

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Inclination - the displacement of the BHA in the inclination plane (up and down from high side) Directional - the displacement of the BHA in the directional plane (side to side) Clearance - the displacement of the BHA from the closest point on the wellbore wall

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A positive value for Direction indicates the string displacement from the wellbore centerline is towards the right side of the wellbore.

The string is in contact with the wellbore wall when the clearance is zero.

A negative value for Inclination indicates the string displacement from the wellbore centerline is towards the low side of the wellbore.

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Side Force Plot

The View > Plot > Side Force plot displays the calculated side force (at each node analyzed) versus distance from bit. This information is also displayed in table form in the BHA Forces section of the report.

In this example, the maximum side force is in the BHA.

Using Predicted Plots

The View > Predicted Plot plots include a number of plots that provide information about the current wellbore, as well as the “drill ahead” interval where you are analyzing how the BHA will drill in the future.

Dogleg Plot

Use View > Predicted Plot > Dogleg Severity to determine the dogleg at any depth in the wellbore, including the “drill ahead” interval. If you do not have the Enable Drillahead box checked on the Parameter > Analysis dialog, this plot is not available. To check the dogleg for the

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existing wellbore (not including the “drillahead” interval) use the View > Wellpath Plots > Dogleg Severity plot.

All depths below the indicated wellbore depth are predicted values in the drillahead interval.

Inclination Plot

Use View > Predicted Plot > Inclination to determine the inclination at any depth in the wellbore, including the “drill ahead” interval. If you do not have the Enable Drillahead box checked on the Parameter > Analysis dialog, this plot is not available. To check the inclination for

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the existing wellbore (not including the “drillahead” interval) use the View > Wellpath Plots > Inclination plot.


Azimuth Plot

Use View > Predicted Plot > Azimuth to determine the azimuth at any depth in the wellbore, including the “drill ahead” interval. If you do not have the Enable Drillahead box checked on the Parameter > Analysis dialog, this plot is not available. To check the azimuth for the existing

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wellbore (not including the “drillahead” interval) use the View > Wellpath Plots > Azimuth plot.


Build Plane Curvature

Use View > Predicted Plot > Build-Plane Curvature to determine the build rate at any depth in the wellbore, including the “drill ahead” interval. If you do not have the Enable Drillahead box checked on the Parameter > Analysis dialog, this plot is not available. To check the build-plane curvature for the existing wellbore (not including the

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“drillahead” interval) use the View > Wellpath Plots > Build-Plane Curvature plot.


Walk Plane Curvature

Use View > Predicted Plot > Walk-Plane Curvature to determine the walk rate at any depth in the wellbore, including the “drill ahead” interval. A positive value indicates a walk to the right, and a negative means a walk to the left. If you do not have the Enable Drillahead box checked on the Parameter > Analysis dialog, this plot is not available. To check the walk-plane curvature for the existing wellbore (not

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including the “drillahead” interval) use the View > Wellpath Plots > Walk-Plane Curvature plot.


Using the BHA Report

Report Options

The Report Options dialog is used to specify what additional information will be included on the report. Using this dialog, you can include or exclude much of the information defining the case you are analyzing.

Using the Report

The BHA report (View > Report > BHA) contains information regarding the forces acting on the bottom hole assembly and the resulting displacements. The BHA report provides information concerning the forces acting on each element and node as well. Using the report, you can: • • • •

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• • •

Determine the stresses acting at each node. Determine the principal stresses acting at each node. Determine the inclination and azimuth of the drill sting.

What is Happening at the Bit?

The BHA report includes a section indicating bit tilt in both inclination and direction planes. This information pertains to the bit only. It is possible to have a negative bit tilt, yet build angle. If this should occur, it is probable that the bit is momentarily tilted downward, and that the assembly is influenced by a positive side force. Always consider all the information presented when analyzing a bottom hole assembly performance.

What are the Forces Acting on the Bottom Hole Assembly?

The BHA Forces section of the report displays the contact force and torque acting on components of the bottom hole assembly. This section indicates where the bottom hole assembly is in contact with the wellbore along with the corresponding side force at the contact point. This information can assist with determining why the assembly is not building or dropping as expected. Perhaps there is no contact between stabilizers for a build assembly, or the contact point is not in the proper location. The BHA Forces information may also be useful in determining areas where casing wear may become a problem commonly in areas where the string contacts the casing in the cased hole section. The Bottom Hole Assembly module will not determine if casing wear is a problem, only that the bottom hole assembly is in contact with the inside of the casing.

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You can determine the contact forces acting on any portion of the string that was analyzed.

If you do not check the Dynamics box on the Analysis Parameters dialog the torque is always equal to the value for torque at bit that you specified.

Where is the Bottom Hole Assembly Located in the Wellbore?

The BHA Displacements section of the report displays how the bottom hole assembly is lying in the wellbore. This information is also displayed in the View > Plots > Displacement plot. This information is also available in the Displacement plot you viewed earlier.

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Clearance is the minimum distance between the drillstring and the wellbore.

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What Force and Moment is Acting at Each Node?

The Element Forces Table contains information regarding the magnitudes of the forces and moments (associated with each degree of freedom) acting on each node. Refer to “Analysis Methodology” on page 525 for more information.

You can determine the forces and moments acting on each element and node.

Notice the assembly is divided into 39 elements using 40 nodes. The force and moment at each node is displayed.

A summary of this information is displayed in the Element Forces Table Summary of the BHA Report. This table displays the minimum and maximum magnitudes of each force and moment along with the corresponding nodes at which these forces or moments occur.

What are the Stresses at Each Node?

The Component Stress Table displays the magnitudes of each stress type (axial, bending, torsion, shear and equivalent) along with the corresponding nodes at which they occur.

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Stress information is reported based on stress type. Notice that several stress types are reported at each node.

What are the Principal Stress Acting at Each Node?

The Principal Stress Table displays the magnitudes of the maximum principal, minimum principal, maximum shear and equivalent stress at each node analyzed.

You can determine the principal stress acting at each node.

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What is the Inclination and Azimuth of the Drillstring or Wellbore?

The final section of the BHA Report—the Hole Section vs. Drillstring Angle Table—contains information related to the inclination and azimuth directions of each node for the string and the wellbore.

You can determine the inclination and azimuth of the string and wellbore at any node.

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Predicting How a Bottom Hole Assembly Will Drill Ahead Drillahead analysis predicts the directional behavior of a bottom hole assembly during the planning stages. Drillahead analysis makes it possible to study the effects of various components, including bent assemblies, collar sizes, stabilizer placement, hole enlargement, and component wear. During well operations, drillahead analysis can be used to adjust operating parameters to optimize performance. The drillahead analysis first performs the same analysis as in the static analysis. The program then drills ahead in 5-foot increments to predict the bottom hole assembly behavior over the user specified drillahead interval. Data is presented on the reports in increments specified by the user. The report generated for the drillahead analysis is similar to the static analysis except that information for the user specified drillahead interval is included.

Defining Analysis Parameters for Drillahead Analysis Use Parameter > Analysis to input parameters needed to perform the calculations. Check Enable Drillahead to analyze how a bottom hole assembly will perform as it makes new hole.

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Analyzing Drillahead Results The reports and plots available for a drillahead analysis are the same as those available for the static analysis discusses previously.

Using the BHA Analysis Data Quick Look Results

The Parameter > Analysis dialog presents a summary of the results in the Quick Look section.

How Will the BHA Drill Ahead?

Refer to the Weight on Bit Study Report section of the BHA Report (View > Report > BHA) to determine how the BHA performs over the specified drillahead interval.

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Predicted wellpath data is appended to the existing wellpath based on the drillahead parameters specified.

Predicted wellpath data is appended to the existing wellpath over the drillahead interval specified.

Why is the BHA Building or Dropping?

To determine why the BHA is performing as it is, use the BHA Forces table on the BHA Report (View > Report > BHA).

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You can determine where the BHA is in contact with the wellbore and the amount of contact force.

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Supporting Information and Calculations The material contained in this section is intended to provide you more detailed information and calculations pertaining to many of the steps presented during the descriptions of the analysis mode methodologies. If the information in this section does not provide you the detail you require, please refer to the section titled “References” on page 541 for additional sources of information pertaining to the topic you are interested in.

Analysis Methodology Three Fundamental Requirements of Structural Analysis

The Finite Element Analysis (FEA) method used in the Bottom Hole Assembly module adheres to three basic conditions of structural analysis: • •

•

First, the internal forces must balance the external forces. Second, the solutions for each separate element must be compatible with the next element. This is necessary so that the deformed structure fits together. Third, the laws of material behavior must be followed.

Defining the Finite Element Mesh

The first step of the analysis divides the drillstring into a 40 element mesh. This 40 element mesh is divided into three sections or “zones.” The Bottom Hole Assembly module has preset defaults for the total length of the mesh, the lengths of the individual zones, and for the elements within the zones. The defaults for lengths of zones 1 and 2 are 500 and 2500 feet, respectively. The length of zone 3 varies depending on the remaining length of drillstring and the remaining number of available nodes. The Aspect Ratios for zones 1, 2 and 3 default to 20, 100, and 500 respectively. The following example explains how Aspect Ratios determine element lengths. Assume there is an 8" collar in zone 1. The maximum element length in zone 1 for an 8" collar would be: 8" X 20 (default for Aspect Ratio 1) = 160" or 13.3 ft. Landmark

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An exception to this is in the bottom 12 feet of zone 1 where there is a 3-foot limit for element length. The 3-foot limit is included because the drillstring closest to the bit has a significant impact on the bottom hole assembly behavior.

Compute the Local Stiffness Matrix and the Global Stiffness Matrix

After the drillstring has been divided into elements, each element is closely examined in terms of geometrical and physical properties. The correct representation of geometrical and physical properties— including component weight, dimensions, moment of inertia and modulus of elasticity—is very important in order to accurately represent the component for the remaining analysis. The Bottom Hole Assembly module has a catalog containing much of the information, but it is important that the user carefully selects each component to model the drillstring as closely as possible. The user should verify that all selected component properties accurately reflect the component. The local stiffness matrix [K] is an important piece of the analysis as it represents how rigid or bendable a component is. The relationship between the stiffness matrix [K], and the nodal forces, displacements, rotations, and moments is defined in Equation 1. (Equation 1) {F} = [K] {δ} where: {F} = vector of nodal loads, and moments [K] = stiffness matrix {δ} = vector of nodal displacements, and rotations

The stiffness matrix [K] is composed of the following:

526

E

= Young’s Modulus (lb/in2)

I

= Moment of Inertia (in4)

L

= Length between nodes (in)

G

= Modulus of Rigidity = E/2 (1+v)

J

= Polar Moment of Inertia = 2I

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v

= Poisson’s Ratio

Young’s Modulus (E) varies with material type. Young’s Moduli for a few common materials are listed below. Material

Young’s Modulus

Steel

29 X 106 psi

Aluminum

10.3 X 106 psi

Monel

26 X 106 psi

Tungsten

87 X 106 psi

Beryllium-copper alloy 19.5 X 106 psi The Moment of Inertia (I) varies based on the cross-section of the element in question. The Moment of Inertia for a tubular element is given in Equation 2. (Equation 2) I= π/64 (OD4 - ID4) where: OD = Outside diameter (in) ID = Inside diameter (in) Equations 1 (page 526) and 2 (above) clearly present the importance of accurately representing the bottom hole assembly components. An incorrect material type or tubular dimension can make a significant difference. Figure 1 (on the following page) is the expanded form of Equation 1 (above), and contains more complete descriptions of the vectors and matrix. The forces and moments acting on the single element in Figure 4 (page 531) are calculated using the matrix algebra illustrated in Figure 1 (page 528). The data in this matrix is for the element between node “n” and node “n+1.” Note that each element is defined by two nodes. There are similar matrices for the element between node “n+1” and node “n+2.”

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(12EI)/L3

Fx(n)

(6EI)/L2 (12EI)/L3

Fy(n) Fz(n)

(-12EI)/L2

(-6EI)/2

(-6EI)/L2 =

θx(n)

(2EI)/L (2EI)/L

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GJ/L (-12EI)/L3

(-6EI)/L2 (-12EI)/L2

(-6EI)/L2 (6EI)/L2

X GJ/L

(12EI)/L3

(6EI)/L2

(-6EI)/L2 (12EI)/L3

-AE/L

Mx(n+1)

Mz(n+1)

Y(n) Z(n)

(-6EI)/L2

4EI/L

Fz(n+1)

My(n+1)

(-6EI)/L2

(6EI)/L2

4EI/L

(6EI)/L2

Fy(n+1)

X(n)

-AE/L

Mz(n) Fx(n+1)

(6EI)/L2

AE/L

Mx(n) My(n)

(-12EI)/L3

(6EI)/L2 (-6EI)/L2

2EI/L GJ/L

θz(n) X(n+1)

(6EI)/L2

Y(n+1)

AE/L 2EI/L

θy(n)

Z(n+1) θx(n+1)

4EI/L

θy(n+1)

4EI/L GJ/L

θz(n+1)


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Figure 1: Expanded Stiffness Matrix Equation

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The individual matrices for all the element are combined to form one matrix for the entire bottom hole assembly. The expanded matrix [K] containing data for all 40 nodes included in the analysis is structured as in the Figure 2 (below). Matrix Structure Stiffness matrix [K] for element between nodes 1 and 2 Nodes 2 and 3 Nodes 3 and 4

Nodes 37 and 38 Nodes 38 and 39 Nodes 39 and 40

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Simplified Beam Element Length L

Y(n)

Y(n+1) Deflected Position

Figure 3 (above) is a simplified beam element to illustrate the angle θ as it is used in Figure 4 (page 531). The angle θ is used to measure the deflection of the element from the reference axis. The individual element stiffness matrices are computed and combined to form the global stiffness matrix. This is a necessary step towards ensuring a complete solution for the entire bottom hole assembly, rather than a number of individual solutions for several elements. The global matrix is a necessary step towards satisfying the fundamental requirements of structural analysis mentioned earlier.

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Degrees of Freedom Single Beam Element

X

Fx(n+1) M x(n+1)

Z

Fz(n+1) M z(n+1) Fx(n) M z(n)

Fy(n+1) M y(n+1)

Fz(n) Node n + 1

Mz(n) Fy(n) Node n

M y(n)

Y

Refer to Figure 4 (above) for an illustration of a single beam element. This particular illustration shows one element with six degrees of freedom (DOF). A DOF is an unknown displacement that can occur at a point, or node. As shown in Figure 4, each node can move along the X, Y and Z axes, constituting three DOF—one DOF along each axis. In addition, there can also be a rotation around each axis. This is an additional three DOF, for a total of six at each node. Notice the forces and moments acting on the beam at each node. During the mesh generation step, the entire bottom hole assembly is divided into 39 similar single beam elements and analyzed.

Boundary Conditions

Boundary conditions are the physical constraints acting on the bottom hole assembly. Boundary conditions are important to the analysis to set how the structure is supported and constrained. Boundary conditions

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make it possible to solve the finite element analysis. The Bottom Hole Assembly module provides six default boundary conditions that can be selected for the top and bottom nodes. The Bottom Hole Assembly module’s system defaults do not apply boundary conditions to nodes between the top and bottom nodes. An experienced user familiar with FEA (and with assistance from Landmark) can define additional boundary conditions and can enforce boundary conditions at additional nodes. It is recommended that the defaults be used unless the user is familiar with finite element analysis methods. The following list defines the seven default boundary conditions selections available for the top and bottom nodes.

532

z

Full pin: All three translations are specified and rotations are free.

z

Full Fix: All three translations and rotations are specified.

z

Pin with Axial Slider: Two lateral translations (X, Y) are specified. Z translation is free, and all three rotations are specified.

z

Fix with Axial Slider: Two lateral translation (X, Y) are specified. Z translation is free, and all three rotations are specified.

z

Fix Axial: Two lateral translations (X, Y) are free. Z is specified, and X,Y, and Z rotations are free.

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Fix Torsion: All three translations (X, Y, Z) are free, two rotations (X, Y) are free, and Z rotation is specified.

z

Fix Rotations: All three translations are free (X, Y, Z) and two lateral rotations (X, Y) are specified, and Z rotation is specified.

Displacements

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Rotations

Description

X

Y

Z

X

Y

Z

Full Pin

Set

Set

Set

Free

Free

Free

Full Fix

Set

Set

Set

Set

Set

Set

Pin with Axial Slider

Set

Set

Free

Free

Free

Free

Fix with Axial Slider

Set

Set

Free

Set

Set

Set

Fix Axial

Free

Free

Set

Free

Free

Free

Fix Torsion

Free

Free

Free

Free

Free

Set

Fix Rotation

Free

Free

Free

Set

Set

Free

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For each of the seven previous types, it is possible to modify the radius, angle, axial displacement, and twist for each type.

z

Radius: Determines the string position from the center of the wellbore. A large value places it against the wellbore.

z

Angle: Locates the string relative to the high side of the hole. A radius of 1.0 unit and an angle of 90 degrees places the string one unit (inch, mm, or so forth) to the right of the center of the hole.

z

Axial Displacement: Used to initially displace the string.

z

Twist: The rotation from the high side of the hole. This is used to impart an initial twist to the string.

Constructing the Wellbore and Bottom Hole Assembly Reference Axis

Wellpath data and wellbore diameters are important pieces of information supplied by the user. The Bottom Hole Assembly module uses this information to construct the wellbore. Each wellpath data point supplied by the user is used to calculate location reference coordinates for each wellpath point of the wellbore using the wellpath calculation method supplied by the user (that is, Radius of Curvature and so forth). Next, the coordinates of the bottom hole assembly nodes are determined as if the bottom hole assembly is lying along the centerline of the wellbore, with the bit at the depth specified by the user. A bottom hole assembly reference axis (Z) is established by using the inclination and direction as interpolated at the bit location. The Z reference axis is tangent to the wellbore and points toward the surface.

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The X and Y reference axes are also established. The X axis points toward the surface (vertical) and theY-axis is parallel to the surface (lateral). Hole diameters are assumed to be constant over the interval specified by the user in the WELLPLAN Wellbore Editor.

Calculating the Solution

Using the information from the previous steps of the analysis, the force/contact solution can be calculated. This is a complex, iterative procedure. First, the drillstring finite element model is laid out along the z-axis described above. Unless the wellbore is straight, the drillstring finite element model penetrates the wellbore described by the wellpath. At this point, the program begins to determine the force acting between the wellbore and the drillstring. The boundary conditions are enforced on the nodes specified. All other nodes have no boundary conditions applied. The program determines where the drillstring has (theoretically) penetrated the wellbore and calculates the restoring force necessary to move the node back into the wellbore. If the node is already inside the wellbore, no force or displacements are applied to the node. These steps are repeated until the changes in displacements at all nodes fall below a set tolerance. The objective is to determine the forces necessary to move the nodes along the reference axis to the corresponding nodal position lying along the wellbore centerline. When this is accomplished, the solution is considered complete. At this point, the axial forces, torque, stresses and coordinates (X, Y, and Z) of each node are known.

Bit Tilt and Resultant Side Force

The following two figures are inclination and directional views of the forces acting on a bit. In these figures, the following nomenclature is used.

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Inclination Forces

FI

FR FA

φΑ φI

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φR

TAN

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Direction Forces N

TAN

θD θA

FR

FA

θR FD

FI = Inclination Force FD = Direction Force FRI = Resultant Inclination Force FR = Resultant Direction Force

φI

= Wellbore Inclination

φA = Bit Inclination Angle φR = Resultant Force Inclination Angle θD = Wellbore Direction Angle θA = Bit Direction Angle θR = Resultant Force Direction Angle These figures can be somewhat misleading because the inclinational (FI) and directional (FD) side forces compared to the axial force (FA) in the diagrams are represented approximately equal in magnitude. In normal operating conditions, the axial force (FA) is usually 10 to 100 times the magnitude of the side forces.

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The bit tilt is defined as the angle between the centerline of the wellbore and the centerline of the bit. As shown, there is a bit tilt in both the inclination and azimuth directions. Bit tilt is a result of the bending characteristics of the bottom hole assembly and the resulting force acting on the bit. The resultant force is a vector solution of all the forces acting on an individual node, and it is this force that determines the magnitude of the displacement from the center line. The bit trajectory is determined by the resultant force acting on the bit and by the bit tilt.

Drillahead Solutions

The Bottom Hole Assembly module is capable of two analysis modes: z

The static or “in-place” solution has been explained in the previous discussion. A static solution assumes the bit is stationary at the user specified depth.

z

The “drillahead” solution advances the bit depth, in 5 foot intervals, through the interval specified by the user. At each of the 5 foot intervals, a static solution is performed. The drillahead solution assumes: • The bit will drill in the direction it is pointed. • The bit will cut sideways due to the presence of side forces generated in the inclination and direction axes. • The formation has isotropic rock properties.

Although side cutting is affected by penetration rate, it is not entirely a function of the same parameters that affect penetration rate. Lateral penetration rates do not always vary with penetration rate. One reason for this can be attributed to the variety of bits available. Different bits have different side cutting abilities. To calculate the lateral penetration rate, the Bottom Hole Assembly module uses the Warren Penetration Rate Model.

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(Equation 3)

Warren Penetration Rate Model CS Ri =

A (S2)(D3)

C +

(RSB)(Fi2)

(RS) (D)

Where: Ri = Lateral penetration rate (ft/hr) CS = Side cutting coefficient = bit coefficient /10.0 S

= Rock strength = formation hardness / 10.0

D

= Bit diameter (in)

Rs = Rotary speed (rpm) Fi

= Lateral side force at the bit (kips)

A

= Bit constant = 0.03

B


C


Bit Coefficient

Bit coefficients indicate how efficient a bit will cut sideways. Values for bit coefficient range from 1 - 100. Note that a value of 0 indicates the bit does not cut sideways, and the wellbore trajectory will be based solely on bit tilt. The following table includes suggested bit coefficients for roller cone bits. Typically range for this type of bit is 20 - 80, with 20 used for soft formations, and 80 used for hard formations. IADC Series

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Bit Coefficient

8

20-30

3,7

30-40

2,6

40-60

1,4,5

60-80

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The values for fixed cutter bit coefficients are more difficult to determine from the IADC classification system. Cutter size, density, and placement impact the determination of bit coefficient. Fixed Cutter Bits

Bit Coefficient

Flat Faced Diamond

0-5

Step Profile/Small Cutters

10-20

Bladed/Small Cutters

20-40

Step Profile/Large Cutters

40-60

Bladed/Large Cutters

60-80

Formation Hardness

Formation hardness is used in Equation 3 (page 539) to model the formations resistance to the bit side cutting capability. Formation hardness is a number between 0 and 60, with the larger numbers indicating the relative hardness of the formation. The table below correlates formation hardness to rate of penetration and formation description. Formation Description

540

Formation Hardness

ROP (ft/hr)

ROP (m/hr)

Soft

10

100+

30+

Medium Soft (Shallow Gulf Coast)

20

75

23

Medium (Above 10,000 feet)

30

50

15

Medium Hard (Below 10,000 feet)

40

30

9

Hard (Granite)

50

20

6

Rigid (Igneous Rock)

60

10

3

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References Millheim, K.K., Jordan, S., and Ritter, C.J., “Bottom Hole Assembly Analysis Using the Finite Element Method,” Journal of Petroleum Technology, February, 1978, 265-74. Warren, T.M., “Factors Affecting Torque for a Roller Cone Bit,” Journal of Petroleum Technology, September 1984, 1500-08. Rockey, K.C., Evans, H.R., Griffiths, D.W., and Nethercot, D.A., “The Finite Element Method,” Granada Publishing Limited, 1975. Williams, J.B., Apostal, M.C., Haduch, G.A., “An Analysis of Predicted Wellbore Trajectory Using a Three-dimensional Model of a Bottomhole Assembly with Bent Sub, Bent Housing, and Eccentric Contact Capabilities,” SPE 19545, 1989. Millheim, K., Jordan, S., Ritter, C.J., “Bottom Hole Assembly Analysis Using the Finite Element Method,” SPE 6057, 1978. Millheim, K., “Directional Drilling” (an 8 part series), Oil and Gas Journal, 1979.

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Chapter 13

Stuck Pipe Analysis Overview During the Stuck Pipe Analysis segment of your WELLPLAN training you will learn the basic functionality of the Stuck Pipe module. The class exercise and workflow are designed to follow a typical workflow using the module. In the future, you can refer to these workflows to assist you with using WELLPLAN. By the end of the Stuck Pipe course you become familiar with the following tasks: Input required data for the analysis. Determine the stuck point. Determine the measured weights required to activate the jar. Determine if the required surface loads with yield the pipe. Determine surface actions to backoff a connection.

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Chapter 13: Stuck Pipe Analysis

Workflow The following steps are designed to be a general guide to the steps involved in using the Stuck Pipe module. This workflow is not intended to suggest that you must follow these steps when using the module. There are certainly other workflows that may meet your analysis requirements. Open a Case using the Well Explorer. Refer to “Using the Well Explorer” on page 55 for instructions on using the Well Explorer. Select the Stuck Pipe module by clicking

.

Define the wellbore. (Case > Hole Section Editor) Define the workstring. Use the String Editor to define all workstrings (drillstrings, tubing, liners, and so forth). (Case > String Editor) Enter deviation (wellpath) data. (Case > Wellpath > Editor) Define the fluids used. You must define the fluid rheological properties, select a rheology model, and specify the temperature. You can define as many fluids as you want. Only one fluid can be used at a time. (Case > Fluid Editor) Specify operational parameters for the analysis. (Case > Stuck Pipe Setup) Optional: Specify standoff device parameters. (Parameter > Standoff Devices) Determine the stuck point if it is not know. Select Stuck Point Analysis from the Mode drop-down list. Use Parameter > Analysis to input stretch test information and calculated stuck point. Determine the loads that can be applied without yielding the string. Select Yield Analysis from the Mode drop-down list. Use Parameter > Analysis to input a range of measured weights and to determine it the string will fail. Determine the surface actions required to set, trip and reset the jar. Select Jar Analysis from the Mode drop-down list. Use

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Parameter > Analysis to input required jar functions and to review the analysis results. Determine the surface actions required to backoff a joint in the string. Select Backoff Analysis from the Mode drop-down list. Use Parameter > Analysis to input the depth to backoff at and the required forces to backoff the joint. Review the analysis results on this dialog.

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Introducing Stuck Pipe Analysis What is the Stuck Pipe Module? Stuck Pipe analysis calculates the forces acting on the drillstring at the stuck point. It can be used to determine the location of the stuck point, the overpull possible without yielding the pipe, the measured weight required to set the jars and the surface action required to achieve the desired conditions at the backoff point. The Stuck Point Module assumes that the pipe is in good condition, has not suffered fatigue damage and that the stresses due to bending are not significant. In the Yield Analysis mode, the drill pipe and heavy weight outside diameters are de-rated according to the pipe class and all principal stresses are calculated. Refer to “Pipe Wall Thickness Modification Due to Pipe Class” on page 233 for more information. Fatigue damage is not considered in the yield analysis. The Stuck Pipe Module includes the following analysis modes: z

Stuck Point Calculations Mode

z

Yield Load Analysis Mode

z

Jar Analysis Mode

z

Backoff Analysis Mode

Why Should I Use the Stuck Pipe Module? Using the Stuck Point Module is superior to hand calculations because hand calculations assume the wellbore is vertical, frictionless and that the drill string is all drill pipe. The Stuck Pipe Module includes the frictional effects of the drill string in a three-dimensional wellbore and adjusts for stretch when the string is buckled. Stuck Pipe uses the WELLPLAN Torque Drag Analysis calculations, including: equilibrium equations and stress, stretch and buckling calculations. Yield load limits are based on the calculated effective yield stress.

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Starting Stuck Pipe There are two ways to begin the Stuck Pipe module: z

Select Stuck Pipe from the Modules menu and then select the appropriate analysis mode.

z

Click the Stuck Pipe Analysis button and then select the appropriate analysis mode from the drop-down list.

Choose Stuck Pipe from Module menu, or by clicking the Stuck Pipe Module button.

Select analysis mode from submenu, or from Mode dropdown list.

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Adding a Jar to the Workstring Workstring are defined using the Case > String Editor. The current string does not have a jar, so it must be added to the string in order to perform Stuck Pipe analysis. Double-click on a noneditable field associated with the jar to access the String Data dialog.

Use the String Data dialog to specify jar setting and tripping forces.

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Determining the Location of the Stuck Point The Stuck Point calculations are similar to those that are provided in a number of drilling engineering text books, hand books, and stretch charts. The difference is that the simple equations used in text books and handbooks assume that the wellbore is vertical and frictionless and the the drill string is all drill pipe. WELLPLAN Stuck Pipe includes the frictional effects of the work string being in the actual three-dimensional wellbore and adjusts the stretch when the pipe is buckled. The Stuck Point Algorithm assumes that the pipe is in good condition, has not suffered fatigue damage, and that stresses due to bending are not significant. In the yield analysis calculations, however, the drill pipe and heavy weight OD is de-rated according to the pipe class and all principal stresses are calculated. Fatigue damage is not considered in the yield analysis.

Defining Analysis Parameters and Viewing Results of Stuck Point Analysis Use Parameter > Analysis to input parameters required to determine the location of the stuck point.

Calculated measured depth of stuck point. 7

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Determining the Surface Measured Weight Required to Activate the Jar After the stuck point has been determined, the next step is to calculate the surface measured weight required to trip and reset the jar. Use the Jar Analysis mode to determine the surface force required to set and trip the jar.

Describing the Jar Analysis Mode One of the major reasons jars are reported as having "failed" is not because they have actually failed, but because of their incorrect use. Often proper consideration is not given to the friction forces that need to be overcome to apply a given force to fire or set a jar. Or the time dependant nature of hydraulic jars is not being taken into account. The same friction affects that create drag and torque losses while drilling deviated wells also affect the loads required to trip a jar. Probably the major reason that a jar does not trip is that the force that is required to be applied to the jar, either compressional or tensional force, is not transmitted to the jar. Due to friction losses the force that is actually applied to the jar can be a fraction of the force that is applied at the surface. The Jar Analysis mode in Stuck Pipe is designed to determine the force that is transmitted to the jar for a given force that is applied at the surface. It is important to remember that this analysis only calculates the forces that are applied to the jar by the application of a given measured weight. It does not calculate the forces generated by the jarring action. The Jar Analysis performs the following calculations: z

Measured weight to set the jar for the first firing, relative to the current measured weight and drag imposed on the drill string.

z

Measured weight to then trip the jar.

z

Measured weight to reset the jar for a subsequent firing in the same direction.

The force that is transmitted from the surface to the jar and the load that causes the jar to trip is dependant on several factors. The factors that are

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specific to the jar being used and the wellbore are entered on the Case > String Editor and the Case > Hole Section Editor, respectively. Other operating parameters are entered on the Parameter > Stuck Pipe Setup Data dialog.

Selecting the Jar Analysis Mode Select the Jar Analysis mode from the drop-down list.

Defining Analysis Parameters and Viewing Results of Jar Analysis Use the Parameter > Analysis dialog to input the data required to determine the surface measured weight required to supply the jar with enough force to trip or reset. The results are displayed on this dialog also. The jar operating forces are specified on the String Data dialog.

Input the measured weight when stuck.

Indicate the direction the jars fire. Select Pumps Off to indicate there is no circulation, or click Pumps On to indicate there is circulation.

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The surface measured weights to set, trip and reset the jar are presented here.

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Analyzing the Output Section

Jar Operating Force Jar Set Force

For mechanical jars, this indicates the force that must be applied to reset the springs into a position to be re-tripped. For hydraulic jars, this is the Jar Seal Friction Force. The Jar Seal Friction force is the force required to move a hydraulic jar from the tripped position to the reset position so it can be tripped again. It represents the force needed to overcome any internal friction forces that exist within hydraulic jars. Exact values should be obtained from the jar manufacturer. There is no set force required for hydraulic jars. When calculating the pick up or set down required to reset a hydraulic jar, the reset measured weight is that measured weight which will place the jar in a neutral position, i.e., set the axial force in the jar equal to zero, whereby a load can be reapplied to re-trip the jar. So, in practice, for hydraulics jars, the jar seal force replaces the jar set force that you enter for mechanical jars. For example, when resetting a jar to trip down, if it is required to put the jar in tension by 100 lbs, enter 100 lbs for the Jar Seal Force (String Editor). The reset measured weight will be calculated which places the jar in 100 lbs tension.The Jar Seal Friction is not required for analyzing mechanical jars. Jar Trip Force

For mechanical jars, this is the force required to trip the jar upwards. Hydraulic jars do not have a specified load at which they trip. A hydraulic jar will trip a finite time after the Jar Set Force is applied. The magnitude of the jar force achieved by the jar is proportional to the rate the Jar Set Force is applied. Time and load cycles are available from the jar manufacturer.

Jar Operating Measured Weight Set (Initial) – Measured Weight

This is the measured weight required to achieve the Jar Set Force in the center of the jar (compressive force). This value is calculated if the input Initial Hookload is not sufficient to set the jar. Set (Initial) - Change

This is the Set (Initial) Measured Weight minus the Measured Weight When Stuck. Set (Initial) - Buckling

This indicates if buckling is occurring at the Set (Initial) Measured Weight and if so, what type of buckling. Buckling is not occurring

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unless an S (Sinusoidal buckling), a T (Transition buckling), an H (Helical buckling) or an L (Lockup) is displayed. A ~ indicates there is no buckling. Trip – Measured Weight

This is the measured weight required to achieve the Jar Trip Force in the center of the jar (tensile force). Trip - Change

This is the measured weight equal to the Trip Measured Weight minus the Set Measured Weight. Trip - Buckling

This indicates if buckling is occurring at the Trip Measured Weight and if so, what type of buckling. Buckling is not occurring unless an S (Sinusoidal buckling), a T (Transition buckling), an H (Helical buckling) or an L (Lockup) is displayed. A ~ indicates there is no buckling. Reset – Measured Weight

This is the measured weight to reset the jar to the Set (Initial) Measured Weight after tripping the jar. This is the force required to set the center of the jar in compression. Reset - Change

This is the measured weight equal to the Reset Measured Weight minus the Trip Measured Weight. Reset - Buckling

This indicates if buckling is occurring at the Reset Measured Weight and if so, what type of buckling. Buckling is not occurring unless an S (Sinusoidal buckling), a T (Transition buckling), an H (Helical buckling) or an L (Lockup) is displayed. A ~ indicates there is no buckling.

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Determining if the Required Measured Weight Yields the String After the stuck point has been determined and the surface measured weight required to trip and reset the jar has been determined, the next step is to determine if the required measured weights will yield the string. Use the Yield Analysis mode to determine if the pipe will yield under the required measured weights.

Describing the Yield Analysis Mode Yield Load Analysis determines the forces acting on the pipe and the formation at the stuck point. The program will apply the specified minimum measured weight and then determine the force in the pipe at the stuck point, the torque required to yield the pipe, and the force that the pipe is applying to the formation at the stuck point. The applied measured weight will be increased by the specified amount and another analysis done. This process repeats until the maximum measured weight specified is analyzed or until it is determined that the pipe has yielded, whichever comes first. As with the stuck pipe calculations, Yield Load Analysis determines when the pipe is buckled and, when it is, applies additional contact forces that affect the axial forces and stretch. In addition, the outside diameters of the drill pipe and heavy weight is de-rated according to the pipe class.

Selecting the Yield Analysis Mode Select the Yield Analysis mode from the drop-down list.

Defining Analysis Parameters and Viewing Results of Yield Analysis Use the Parameter > Analysis dialog to input the data required to determine if the surface measured weight required to supply the jar with

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enough force to trip or reset will yield the string. The results are displayed on this dialog also.

Specify the minimum measured weight to use in the yield analysis. The analysis will apply this measured weight and then determine the force in the pipe at the stuck point, the torque required to yield the pipe, and the force that the pipe is applying to the formation at the stuck point. The minimum measured weight will be increased by the increment and calculated the forces at the stuck point. This process repeats until the maximum weight is analyzed or until it is determined that the pipe has yielded, whichever comes first.

The string does not yield in this analysis. If it did, the component and depth would be displayed here. (DP at 0 MD is the default for indicating yield did not occur.)

These data refer to the stuck point.

Analyzing the Output

Initial Status at Surface Rotary Table Torque

The rotary table torque is calculated using the Torque Drag Normal Analysis General Analysis Steps. This analysis assumes the axial force at the bottom of the string is known and calculates the forces up the string to the surface.

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Initial Status at Stuck Point Force in Drill String (PA)

This is the axial force in the drillstring at the stuck point calculated using the pressure area method. Refer to Axial Force Calculations for more information. Force in Drill String (BUOY)

This is the axial force in the drillstring at the stuck point calculated using the buoyancy method. Refer to Axial Force Calculations for more information. Torque in Drill String

This value is always zero. Force at the Stuck Point

This is the calculated force at the stuck point. Torque at the Stuck Point

This is the calculated torque in the drillstring at the stuck point.

Minimum Overpull to Load Stuck Point Measured Weight

This is the calculated overpull measured weight. During the analysis, if the operating measured weight is greater than the overpull measured weight calculated during the reference solution, the corrected solution will be performed and the overpull measured weight will be set equal to the operating condition measured weight. Overpull

This is the final calculated overpull measured weight minus the measured weight when stuck.

Minimum Slackoff to Load Stuck Point Measured Weight

This is the calculated slackoff measured weight. During the analysis, if the operating condition measured weight is less than the overpull measured weight calculated during the reference solution, the corrected solution will be performed and the slackoff measured weight will be set equal to the operating condition measured weight. Slackoff

The final calculated slackoff measured weight minus the measured weight when stuck.

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Output Applied Weights Applied Measured Weight

The applied measured weight is the measured weight used in the analysis. The applied measured weight range used in the analysis is determined by the Minimum, the Maximum, and the Increment. Maximum Rotary Torque

This value is the calculated maximum torque required to increase the von Mises stress to the failure limit using the corresponding Applied Measured Weight and assuming all other stresses are constant. If the Applied Measured Weight is between the calculated values of minimum overpull and maximum slackoff, it is unknown which direction the drag forces are acting. The directions of the drag forces are necessary to calculate the forces along the string. The maximum torque to fail the drillstring cannot be calculated without calculating the forces along the string first. Overpull/Slackoff

This value is the Applied Measured Weight minus the Measured Weight When Stuck. Yield Point - Section

This is the workstring component where the induced yield occurred as a result of the calculated Maximum Rotary Torque. Yield Point – Measured Depth

This is the measured depth of the workstring component that yielded as a result of the calculated Maximum Rotary Torque. Force in Drill String – Pressure Area

This is the calculated axial force in the drill string using the pressure area method. Force in Drill String – Buoyancy

This is the calculated axial force in the drill string using the buoyancy method. Stuck Point - Force

This is the force required to hold the string in place at the stuck point. Stuck Point - Buckling

This indicates the type of buckling occurring. The buckling modes are: ~ - No buckling, S – Sinusoidal, H – Helical, L – Lockup. Torque

This is the calculated torque at the stuck point. This torque is equal to the Maximum Rotary Torque minus the accumulated string torque from the surface to the stuck point.

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Determining if the Required Force at Backoff Connection Can be Achieved Describing the Backoff Analysis Mode The optimum conditions for performing a back off is to ensure the joint in question are in a neutral position, zero axial force, or slightly in tension. It is also beneficial to place a small amount of left hand torque at the connection to be backed off. The Backoff Analysis mode determines the amount of pick up or slack off force and torque required at the surface to achieve the specified axial force and torque at the connection to be backed off.

Selecting the Backoff Analysis Mode

Select the Backoff Analysis mode from the drop-down list.

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Defining Analysis Parameters and Viewing Results of Backoff Analysis Use the Parameter > Analysis dialog to input the data required to determine if the surface actions required to backoff at a specified depth. The results are displayed on this dialog also.

Analyzing the Output

Condition Prior to Backoff

This section analyzes the forces at the backoff point and the surface condition just prior to becoming stuck (Before Stuck) and just before the backoff operation (Current). The assumption is that the driller will have worked the pipe after becoming stuck and both states need to be analyzed. The section calculates the Before Stuck measured weight, rotary table torque, force and torque at the backoff point based on the Operating Mode When Stuck. Then the Current Measured Weight is calculated if it was not input as the Measured Weight When Stuck. The rotary table torque and the force and torque at the backoff point just prior to starting the backoff operation are also calculated. Measured Weight – Before Stuck

This is the measured weight before becoming stuck and is based on the Operating Mode Before Stuck. Measured Weight – After Stuck

This is the measured weight after becoming stuck and is calculated based on the Operating Mode Before Stuck.

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Rotary Table Torque – Before Stuck

This is the rotary table torque before becoming stuck and is based on the Operating Mode Before Stuck. For tripping cases, the rotary table torque will be zero. Rotary Table Torque – After Stuck

This is the rotary table torque after becoming stuck and is calculated based on the Operating Mode Before Stuck. For tripping cases, the rotary table torque will be zero. Force At Backoff MD (PA) – Before Stuck

This force is equal to the calculated Measured Weight Before Stuck minus the hoisting equipment weight and the tripping out axial force at the backoff point. This force is calculated using the pressure area method. Refer to Axial Force Calculations for more information. Force At Backoff MD (PA) – After Stuck

This force is equal to the calculated Measured Weight Current minus the hoisting equipment weight and the tripping out axial force at the backoff point. This force is calculated using the pressure area method. Refer to Axial Force Calculations for more information. Force At Backoff MD (BUOY) – Before Stuck

This force is equal to the calculated Measured Weight Before Stuck minus the hoisting equipment weight and the tripping out axial force at the backoff point. This force is calculated using the buoyancy method. Refer to Axial Force Calculations for more information. Force At Backoff MD (BUOY) – After Stuck

This force is equal to the calculated Measured Weight Current minus the hoisting equipment weight and the tripping out axial force at the backoff point. This force is calculated using the buoyancy method. Refer to Axial Force Calculations for more information. Torque At Backoff MD – Before Stuck

The torque is calculated based on the side force of the component acting on the wellbore, the coefficient of friction entered for the corresponding hole section, and the length of the string section. Torque At Backoff MD – After Stuck

The torque is calculated based on the side force of the component acting on the wellbore, the coefficient of friction entered for the corresponding hole section, and the length of the string section.

Initial Surface Action for Set Up

This section displays the surface action required to leave the pipe above the backoff point in tension after the backoff force has been reached. When the pipe became stuck, if the force at the backoff

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point is less than the desired backoff force, the string will have to be picked up to reached the desired backoff force. In this case, no other surface is necessary and the Initial Surface Action for Setup section will not be displayed. However, when the pipe became stuck, if the force at the backoff point is greater than the desired backoff force, the string will have to be slacked off to reach the desired backoff force, thus leaving at least part of the string above the backoff point in compression. In this case, in order to leave the string above the backoff point in tension, the driller will have to slack off enough to overcome the drag forces above the stuck point, then pick up until the desired backoff force is reached. Measured Weight

This is the measured weight required to place the pipe above the backoff point in tension prior to performing the backoff. This action is necessary if the force at the backoff point when the pipe became stuck is greater than the desired backoff force. If this is the case, the string must be slacked off to reach the desired backoff force. It is necessary to slack off enough to overcome the drag forces above the stuck point, and then pick up until the desired backoff force is reached. This information will not be reported if the force at the backoff point when the pipe became stuck is less than the desired backoff force. In this case, the only action required will be to pick up until the desired backoff force is achieved. Minimum Initial Overpull (+ve) / Slackoff (-ve)

This is the Initial Surface Action for Set Up minus the Measured Weight When Stuck. If this is a positive number, it is overpull. If it is a negative number, it is slackoff.

Final Surface Action for Backoff

This section lists the surface action that will need to be taken in order to achieve the desired backoff force and torque. Measured Weight

This is the trip out force to the backoff measured weight plus the backoff force and the hoisting equipment weight. Rotary Table Torque

This is the calculated rotary table torque necessary to achieve the required backoff torque. Overpull (+ve) / Slackoff (-ve) from Set Up Measured Weight

This is the Final Surface Action for Set Up minus the Initial Surface Action for Set Up. If this is a positive number, it is overpull. If it is a negative number, it is slackoff.

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Supporting Information and Calculations The material contained in this section is intended to provide you more detailed information and calculations pertaining to many of the steps presented during the descriptions of the analysis mode methodologies. If the information in this section does not provide you the detail you require, please refer to the section titled “References” on page 567 for additional sources of information.

Stuck Point Algorithm The stuck point measured depth is defined as the measured depth where the total string change in length (during the stretch test) is equal to the observed change in length at the surface. The change in length is induced during the stretch test. The calculations consider the three-dimensional wellbore and the forces acting on the string in the wellbore, including drag, buckling and ballooning. The calculations begin at the surface by applying an axial force equal to the measured weight minus the hoisting equipment weight. The analysis proceeds down the string by calculating the change in length due to Hooke’s Law, buckling and ballooning. When the difference in string length change matches the input value of stretch (on the Stuck Pipe Stuck Point Analysis Dialog, the measured depth of the stuck point is determined as the depth having the same stretch as input stretch.

Stuck Pipe Yield Analysis Algorithm The following is a general outline of the calculations performed during a Stuck Pipe Yield Analysis. 1. If the measured depth of the stuck point is not specified, it is determined by using the Stuck Point Algorithm. 2. The next step in the analysis is to determine the forces acting at the stuck point and to determine the rotary table torque. To accomplish this, the analysis begins by assuming that the forces at the bottom of the string are known. A Torque Drag Normal Analysis is performed using the analysis outlined in Normal Analysis General Analysis

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Steps on page page 209. During this analysis, the setup data specified on the Stuck Pipe Setup Data dialog is used, rather than those specified on the Mode Data dialog (Normal Analysis). 3. The analysis assumes the forces at the stuck point are known (as calculated in the previous step) and calculates an overpull measured weight. This is the measured weight when all of the drag forces between the stuck point and the surface are directed downward and the string is being pulled out of the hole and generating overpull. This information is reported in the Minimum Overpull To Load Stuck Point section on the Stuck Pipe - Yield Analysis dialog. 4. Again the analysis assumes the forces at the stuck point are known (as calculated in the previous step and calculates an slackoff measured weight. This is the measured weight when all of the drag forces between the stuck point and the surface are directed upward, and therefore the string is being lowered into the wellbore and generating slackoff. This information is reported in the Minimum Slackoff To Load Stuck Point section on the Stuck Pipe - Yield Analysis dialog. 5. This step is omitted unless the measured weight at the stuck point (calculated in step two) does not fall between the measured weights calculated in steps three and four, then a Torque Drag Top Down Analysis is performed assuming the forces at the surface are known. Refer to Top-Down Analysis General Analysis Steps on page 214 for more information about the Top Down Analysis. 6. Using the measure weight range and increment specified in the Applied Load Measured Weights section of the Stuck Pipe - Yield Analysis Dialog, various measured weights are analyzed. For each measured weight, points along the string from the stuck point to the surface are analyzed. The analysis considers the forces acting at each point along the string, the wellbore geometry, drillstring configuration, and wellbore curvature. At each point analyzed, the radial, shear, hoop, bending, buckling and axial stresses are determined. Using the appropriate material yield stress for the component located at the point in the string being analyzed, the failure stress is calculated. The torsional stress required to increase the von Mises stress to the failure limit is calculated. This procedure is repeated at various points up the string until failure occurs. Results are displayed in the Output Applied Weights section of the Stuck Pipe - Yield Analysis Dialog.

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Stuck Pipe Jar Analysis Calculations The Stuck Pipe Jar Analysis mode determines the change in measured weight (from the current weight) to set, trip and reset a jar. This module uses the Torque Drag Normal Analysis General Analysis Steps on page 209 to determine the axial forces acting on the string from the jar up to the surface. The analysis considers the wellbore three-dimensional geometry, annular cross sectional area, and drillstring configuration when determining the axial force. After the measured weight required to set or trip a jar is determined, the Jar Analysis mode can help determine if the force can actually be applied to the jar. The analysis calculates the buckling tendency and determines if buckling will occur. Based on this analysis, the correct positioning and selection of a jar can be made.

Up Jar Operation Mechanical Jar:

Effective Up Jar Set Force = Up Jar Set Force Hydraulic Jar:

Effective Up Jar Set Force = Jar Seal Friction Force Hydro-Mechanical Jar:

Effective Up Jar Set Force = Jar Seal Friction Force

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Set:

FS = FTI − FSU − FP + WH

Trip:

FT = FTO + FTU − FP + WH

Reset:

FR = FS

Down Jar Operation Mechanical Jar:

Effective Up Jar Set Force = Down Jar Set Force Hydraulic Jar:

Effective Down Jar Set Force = Jar Seal Friction Force Hydro-Mechanical Jar:

Effective Down Jar Set Force = Down Jar Set Force

Set:

FS = FTO + FSD − FP + WH

Trip: FT = FTI − FTD − FP + WH

Reset:

FR = FS Where:

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FTI= Trip In Axial Force FTO = Trip Out Axial Force DM = Measured Depth FW = Weight Force Gradient FD = Drag Force Gradient FS = Set Measured Weight FSU = Effective Up Jar Set Force FP = Pump Open Force WH = Hoisting Equipment Weight FT = Trip Measured Weight FTO = Up Jar Trip Force FR = Reset Measured Weight FSD = Down Jar Set Force FTD = Down Jar Trip Force

Stuck Pipe Backoff Analysis Calculations The Stuck Point Backoff Analysis mode uses the calculations outlined in the Torque Drag Normal Analysis General Analysis Steps. Refer to “Normal Analysis” on page 209 for more information on the Torque Drag Normal Analysis.

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References G.A. Haduch, R.L. Procter, and D.A. Samuels, "Solution of Common Stuck Pipe Problems Through the Adaptation of Torque/Drag Calculations", SPE 27490. Marcus R. Skeem, Morton B. Friedman, and Bruce H. Walker, "Drillstring Dynamics During Jar Operation", SPE 7521. W.E. Askew, "Computerized Drilling Jar Placement", SPE 14746 M.S. Kaisi and J.K. Wang, "Transient Dynamic Analysis of the Drillstring Under Jarring Operation Using Finite Element Method", SPE 13446. T.V. Aarrestad, Statoil, Stavanger, "Drag Calculations Improve Efficiency of Hydraulic Jars", OIL AND GAS JOURNAL, Mar 29, 1993.

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Chapter 14

Notebook Overview Notebook provides a wide range of simple operational calculations. The calculations in Notebook are divided into three categories, including: Miscellaneous, Fluids, Analysis, and Hydraulics In this section of the course, you will become familiar with all aspects of using the Notebook module. To reinforce what you learn in the class lecture, you will have the opportunity to complete several exercises designed to prepare you for using the program outside of class. The information presented in this chapter can be used as a study guide during the course, and can also be used as a reference for future torque and drag analysis.

Starting Notebook You must have a Case open to use the Notebook module even though case data will not be used in any analysis within the Notebook module. There are two ways to launch the Notebook module.

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z

Select Notebook from the Modules Menu

z

Click the Notebook button

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on the Modules Toolbar.

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Chapter 14: Notebook

Choose Notebook from Module menu, or by clicking the Notebook button.

Select desired analysis mode from submenu or from Mode drop down list.

Notebook Analysis Modes Notebook offers four analysis modes. The analysis mode are essentially a grouping of similar operational calculations. The analysis modes or groups are:

570

z

Miscellaneous - This group of calculations include: determining the linear weight (in air and buoyed) of a component or a section of pipe, calculating the block line cut off length and analyzing leak off test data.

z

Fluids - This group of calculations can be used to achieve the desired fluid weight by mixing fluids, diluting, or weight up. You can also determine the compressibility of a water or oil based mud.

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Hydraulics - This group of calculations can be used to determine the pump output, annular and pipe volumes, nozzle TFA or sizes, and buoyancy factors.

z

Analysis - This group of calculations can be used to determine workstring length, elongation, and weight. It is also used to determine string volumes and fluid heights, as well as spotting pills, block line work, and rig capacity.

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Miscellaneous Mode To access the Miscellaneous mode, select Miscellaneous from the Mode drop down list. The Miscellaneous mode calculates: z

Linear Weight

z

Blockline Cut Off Length

z

Leak Off Test

Linear Weight Use the Parameter > Linear Weight dialog to quickly calculate the weight-in-air and buoyed-weight of a component based on a specified OD, ID, and mud weight. To calculate the linear weight, specify the components ID and OD, its length, the density of the mud, and whether it is a steel or aluminum component.

Click in output section to calculate and view results

Specify component material.

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Blockline Cut Off Length Use the Parameter > Blockline Cut Off dialog to quickly calculate the recommended cut-off length for rotary drilling lines. These calculation values are based on API RP 9B.

Select a Drum Diameter from the list of drum

Click a radio button to select Drum Type.

diameters suitable for the respective mast height.

Select a Mast Height from the list.

View results

Leak Off Test Use the Parameter > Leak Off Test dialog to quickly calculate the formation breakdown pressure and equivalent mud gradient from a leak off test (LOT).

The air gap and sea depth can be set to zero for a land rig.

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Fluids Mode To access the Fluids analysis mode, select Fluids from the Mode drop down list. The Fluids Mode calculates: z

Mix Fluids

z

Dilute / Weight Up

z

Fluid Compressibility

Mix Fluids Use the Parameter > Mix Fluids dialog to quickly calculate the density and volume of a fluid when two fluids with different densities and volumes are mixed. Specify initial volume and density of one fluid. Specify the density and volume of the second fluid. Click in output to view results.

Dilute /Weight Up Use the Parameter > Dilute/Weight Up dialog to calculate the resulting volume when the density of a fluid is increased or decreased to a different density. You can opt to keep the volume constant. In this case, the required dump volume is determined. To calculate a volume, specify the volume and density of the initial fluid, the density of the final fluid mixture, and the density of the heavier fluid you want added. If you mark the Maintain total volume check box,

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the total volume of the final mixture will not be allowed to exceed the volume specified in the Initial Volume field. You must specify volumes in all fields in order for a resulting volume to be calculated.

Enter the volume and density of your original fluid.

Specify the density of the fluid you are using to dilute or weight up the original fluid with.

Required operation achieve required density will be indicated.

Check box to keep volume constant. If this box is checked, the Initial Dump Volume will be calculated.

Fluid Compressibility Use the Parameter > Fluid Compressibility dialog to quickly calculate the volume of mud that must be pumped to overcome the compressibility of the fluid.

Click in output section to view results.

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Hydraulics Mode To access the Hydraulics Mode, select Hydraulics from the Mode drop down list. The Hydraulics mode calculates: z

Pump Output

z

Annular capacity, volume and velocity

z

Pipe capacity, volume and velocity

z

Nozzle TFA or sizes based on TFA

z

Buoyancy factors

Pump Output Use the Parameter > Pump Output dialog to quickly calculate the flow rate and volume-per-stroke for a user-defined pump configuration.

Rod diameter is not required for a triplex pump.

Annular Use the Parameter > Annular dialog to calculate the capacity, volume, and velocity for two annular sections.

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Total annular volume

Enter data for first annular section.

Calculated data for sections.

Enter data for second annular section.

Pipe Use the Parameter > Pipe dialog to calculate the linear capacity, volume, linear displacement, total displacement and velocity for two pipe sections.

Total pipe capacity Total fluid displacement

Enter data for one pipe section.

Calculated results for each section. Enter data for second pipe section.

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Nozzles Use the Parameter > Nozzles dialog to calculate the nozzle sizes required to produce a desired total flow area (TFA) or to calculate the TFA based on a specified number and sizes of nozzles. Click Nozzles to calculate nozzle sizes base on specified TFA.

Input size and number of nozzles to calculate TFA.

Click Total Flow Area to calculate TFA based on specified nozzle sizes

Buoyancy Use the Parameter > Buoyancy dialog to quickly calculate the buoyancy factor based on the specified mud density. Specify mud weight Click in output section to calculate the buoyancy factor

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Analysis Mode To access the Analysis Mode, select Analysis from the Mode drop down list. The Analysis mode calculates: z

Workstring length, elongation, and weight

z

String volumes and fluid heights

z

Spotting pills

z

Block line work

z

Rig capacity

WorkString Maximum String Length

Use this analysis to determine the maximum length of drill pipe that can be used before it fails under its own weight. The wellbore is assumed to be vertical. To determine the Maximum String Length

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Define the active Drillstring/BHA in the Case > String Editor spreadsheet.

z

Define the fluid in the Case > Fluid Editor.

z

Specify either the Margin of Overpull (MOP) or the Safety Factor to be applied.

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Note: Component grade...

The grade of the component defined in the active Drill String is considered by the calculations. If the active component defined in the Case > String Editor Spreadsheet is a grade other than E, X, G, or S grade, then the system will automatically assume the grade to be G grade for the purpose of the calculations.

String Weight

The String Weight Analysis allows the calculation of the Weight in Air and the Buoyed Weight of the current active Drillstring (as defined in the Case > String Editor spreadsheet.). The Wellbore is assumed to be a vertical. To Determine the String Weight: z

Define an active workstring using the String Editor Spreadsheet.

z

Specify the bit depth of the active work string. (The bit depth can be specified in the String Weight Analysis window of Notebook.)

z

Enter the mud weight. (The mud weight can be specified in the String Weight Analysis window of Notebook.)

Elongation

Use this analysis to calculate the elongation of the BHA described in the Case > String Editor spreadsheet. The BHA is assumed to be in a vertical wellbore.

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Volumes and Heights The volumes and heights dialog allows the calculation of: z

End position of a certain volume, given the start position, in either the annulus or the string

z

Start position of a certain volume, given the end position, in either the annulus or the string

z

Volume of fluid required fill between two depths in either the annulus or the string

Each of these three options is calculated by selecting the appropriate radio button. The option that is selected by the radio button is the one that will be calculated. The remaining two fields that are not selected by the radio buttons require data to be input. The String and Annulus radio buttons determine whether the results apply to the string or the annulus sections respectively. The valid values for Start and End Position are limited by:

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Maximum string depth if the String option has been selected

z

Maximum wellbore depth if the Annulus option has been selected

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Note: Volumes...

It is possible that a volume is specified that can not fit in the available space (Start Position > 0, End Position < String Depth or Well bore depth). If this occurs, the volume will be automatically adapted to the maximum value that can be contained.

Lag Times The Lag Time calculator determines the number of strokes (based on a user defined pump configuration) to circulate a sample from a specified depth. The calculations are performed using the workstring defined in the Case > String Editor Spreadsheet and the wellbore defined in the Case > Hole Section Editor. To specify the depth range, enter the start depth, end depth and interval that the calculations will be performed over. Define the pump configuration in the Lag Strokes input window by clicking the Pump Equipment button. This will display the Pump Output window where the type and configuration of the pump must be defined. To calculate the lag strokes, click the Close button after the pump data and the depth range and interval have been defined. The results will be displayed in the output window. For each depth the number of strokes to return the sample/fluid from that depth to the surface is reported.

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Note: Assumes bit is on bottom...

In each case it is assumed that the bit is on bottom for each calculation depth. For example if you specify a range 5000 ft- 6000 ft in 100 ft increments, the results will report the number of strokes to circulate the sample from 5000ft to surface whilst the bit is on bottom at 5000 ft. The next calculation assumes the bit is now on bottom at 5100 ft and the calculations now compute the number of strokes to circulate from 5100 ft to surface. This is repeated for each depth increment.

Spot a Pill This analysis calculates the volume of fluid that needs to be pumped to Spot a Pill so that the bottom of the pill is at the depth specified. The calculations are performed based on the workstring defined in the String Editor Spreadsheet and Wellbore defined in the Hole Section Editor. Simply enter the depth at which the bottom of the pill is to be placed. The volume of fluid to be pumped is reported in the output section.

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Block Line Work These calculations use the active data as defined in the Workstring and Wellbore Editor. The well is assumed to be vertical To calculate the Block Line Work for drilling, tripping or coring, first specify the Hoisting Equipment details then enter the input data on the Drilling Block Line Work Window.

Note: Dialog behavior...

This dialog behaves differently depending on whether the active drillstring defined is a BHA or casing string.

Rig Capacity Determines the loads applied to the rig based on the Active Workstring and Active Wellbore. The calculations assumes a vertical wellbore.

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Before any calculations are performed it is necessary to define the Hoisting Equipment configuration.

Note: Dialog behavior...

This dialog behaves differently depending on whether the active drillstring defined is a BHA or casing string.

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Calculations Block Line Cut Off Length

Length = Laps × Drum Diameter ×

Π 12

Dilute/Wt Up Fluid V1 D1 +V 2D 2 = V 3 D 3 Where:

V1 D1 V2 D2 V3

= Volume of second material to be mixed

D3

= Density of total volume

= Volume of one material to be mixed = Density of V1 material = Density of V 2 material = Total volume

Fluid Buoyancy

Buoyancy = 1 −

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Fluid Compressibility

Vol to Pump [bbl ] =

Test Pressure [ psi ] × Hole Volume [bbl ] Constant

where:

Constant for oil-based mud Constant for water-based mud

= 2.2e5 = 3.16e5

Leak Off Test Formation Breakdown Pressure = TVD × 0.052 × Mud Density + Test Pressure Density Equivalent Mud Gradient =

Formation Breakdown Pressure TVD

Formation Breakdown Gradient =

Formation Brekdown Pressure − Sea Depth × Seawater Gradient TVD − AirGap − Sea Depth

Mix Fluids V1 D1 +V 2D 2 = V 3 D 3 Where:

V1 D1 V2 D2 V3

D3

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= Volume of one material to be mixed = Density of V1 material = Volume of second material to be mixed = Density of V 2 material = Total volume = Density of total volume

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Pump Output

For a duplex pum p

Q = 1 . 568 e −6 × L ( 2 × d r − d y ) × N × η 2

2

W here:

L

= stroke length

dl

= liner diam eter

dr

= rod diam eter

N

= stroke rate

η

= volum etric efficiency

For a triplex pum p:

Q = 2 . 3555 e − 6 × L × d l × N × η 2

Nozzle Area

Π d  TFA = ∑ ni  × ( i )   4 32  i =1 n

2

Where:

di

= Size of the nozzle

ni

= Number of nozzles in each group

i = Number of groups

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Manual Well Plan

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