StressCheck - 5000.1.13

StressCheck™ Software, Release 5000.1.13 Training Manual © 2014 Halliburton

Part Number 161778 Revision H

January 2015

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Contents Chapter 1: Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 What is the StressCheck™ Software? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Course Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Training Course and Manual Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Licensing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-1 1-2 1-3 1-3

Chapter 2: Theory, Calculations, and References . . . . . . . . . . . . . . 2-1 Casing Design Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2 Wellbore Temperatures and Casing Design. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4 Temperature Deration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Drilling Temperatures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Production Temperatures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Initial Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2-4 2-5 2-6 2-7

Basic Material Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9 Stress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9 Strain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9 Modulus of Elasticity (Young’s Modulus) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9 Yield Strength (Tensile) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10

Pipe Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11 Axial . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Burst . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Collapse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Yield Strength Collapse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Plastic Collapse. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Transition Collapse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Elastic Collapse. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Diameter to Wall Thickness Regions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Effect of Tension on Collapse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Effect of Internal Pressure on Collapse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Reduced Wall vs. Nominal Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

StressCheckTM Software Release 5000.1.13 Training Manual

2-11 2-12 2-12 2-13 2-13 2-14 2-14 2-15 2-16 2-16 2-18

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Contents

Tension due to Bending . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-19

Triaxial Stress Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-20 Von Mises Equation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-20 Triaxial Design Ellipse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-21

Buckling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23 Casing Buckling in Oil Field Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-24

API Connection Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-25 Preliminary Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-26 Why Should You Do A Preliminary Design?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . What Data is needed to perform a Preliminary Design? . . . . . . . . . . . . . . . . . Minimum Casing Diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Minimum Casing Shoe Setting Depth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2-26 2-26 2-26 2-27

Detailed Mechanical Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-28 Burst Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Drilling Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Production Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Collapse Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Drilling Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Production Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Axial Loads. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Running and Cementing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Service Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Load Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Automatic Load Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Design Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Design Factor Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Graphical Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Load Line Corrections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2-28 2-28 2-36 2-38 2-38 2-41 2-43 2-43 2-46 2-46 2-46 2-47 2-47 2-48 2-48

External Pressure Profiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-50 Mud and Cement Mix-Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Permeable Zones. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Poor Cement Disabled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Poor Cement Enabled – High Pressure Zone . . . . . . . . . . . . . . . . . . . . . . . . . . Poor Cement Enabled—Low Pressure Zone . . . . . . . . . . . . . . . . . . . . . . . . . . Minimum Formation Pore Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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2-50 2-51 2-51 2-52 2-53 2-54

Contents

TOC Inside Previous Shoe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TOC in Open Hole (with and without Mud Drop Enabled) . . . . . . . . . . . . . . . Pore Pressure w/ Seawater Gradient . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fluid Gradients w/ Pore Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mud and Cement Slurry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Frac @ Prior Shoe with Gas Gradient Above. . . . . . . . . . . . . . . . . . . . . . . . . . . . . Shoe/Mud Gradients w/ Pore Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hydrostatic Isolation Depth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2-54 2-55 2-56 2-57 2-58 2-59 2-59 2-61

Chapter 3: EDM™ and the Well Explorer . . . . . . . . . . . . . . . . . . . . . . . 3-1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2 Describing the Data Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3 Well Explorer Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4

Working with the Well Explorer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6 Drag-and-drop Rules. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6 Instant Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6 Import . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7 Export . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8 Attachments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9 Well Explorer Node Properties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11 Data Locking. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11 General Tab. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13 Audit Tabs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14

Datums . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15 Project Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . System Datum. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Elevation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Well Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Depth Reference Datum(s) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Design Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . General Tab (Design Properties Dialog Box). . . . . . . . . . . . . . . . . . . . . . . . . . Depth Reference Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Workflow—How to Set Up Datums for a Design . . . . . . . . . . . . . . . . . . . . . . . . . Changing the Datum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . How This Works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


3-15 3-15 3-15 3-15 3-16 3-19 3-19 3-20 3-20 3-22 3-22

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Concurrency and Multi-user Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-24 SAM in the Application Status Bar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SAM in the Well Explorer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Reload Notification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Reload . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ignore . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cancel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-24 3-25 3-26 3-26 3-26 3-27

Working with Catalogs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-28

Chapter 4: Getting Started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1 Workflow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2 Enter General Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2 Specify Design Parameters for a Casing String . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3 View Graphical Results and Perform Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3

Getting Started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5 Starting the StressCheck™ Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5

Files and Templates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7 What Type of Files Does the StressCheck™ Software Use? . . . . . . . . . . . . . . . . . . What is a Template File? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Opening an Existing Template File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Saving a Template File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4-7 4-7 4-8 4-9

Main Window Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10 Title Bar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Menu Bar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . File Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Edit Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Wellbore Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tubular Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . View Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Composer Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tools Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Window Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Help Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Wizard Toolbar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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4-11 4-11 4-11 4-11 4-11 4-11 4-12 4-12 4-12 4-12 4-12 4-12

Contents

Data Entry Forms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13 Dialog Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13 Spreadsheets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-14

Helpful Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-15 Online Help. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Setting Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Design Plots Group Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Spreadsheets and Tables Group Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Print Layout Group Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Depths Group Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Safety Factors Group Box. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MMS Report Group Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Other Group Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Configuring Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Using the Unit System Dialog Box. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Using the Convert Unit Dialog Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Using the Convert Unit Dialog Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Customizing Graphical Views . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Changing Plot Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Zooming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Configuring the Well Schematic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4-15 4-16 4-16 4-17 4-18 4-19 4-19 4-19 4-20 4-21 4-21 4-22 4-24 4-26 4-27 4-28 4-28

Accessing and Managing Pipe Inventory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-29 Selecting and Deleting Pipes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Modifying Existing Pipes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Inserting a New Pipe. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tubular Properties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Locking Tubular Properties and Password Security. . . . . . . . . . . . . . . . . . . . . Importing and Exporting Tubular Properties . . . . . . . . . . . . . . . . . . . . . . . . . . Grades . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Temperature Derations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4-31 4-33 4-34 4-34 4-35 4-36 4-36 4-38 4-40 4-41

Chapter 5: Well and Formation Information . . . . . . . . . . . . . . . . . . . . 5-1 Entering Well Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2 Creating a New Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2


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Design Properties Dialog Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2 Entering General Well Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6 Field and Controls. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7 Entering Pore Pressure Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8 Pore Pressure Spreadsheet Columns. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9 Entering Fracture Gradient Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-10 Fracture Gradient Spreadsheet Columns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-11 Defining a Squeezing Salt/Shale Zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-12 Squeezing Salt/Shale Spreadsheet Columns. . . . . . . . . . . . . . . . . . . . . . . . . . . 5-12 Managing Wellpath Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-14 Entering Wellpath Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-14 Import Wellpath File. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-15 Dogleg Severity Overrides Spreadsheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-16 Defining the Geothermal Gradient . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-19 Fields and Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-19 What Effect Does Temperature Have on the Analysis? . . . . . . . . . . . . . . . . . . 5-21 Define the Casing and Tubing Scheme. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-22 Fields and Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-23 Well Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-27 Defining Production Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-28 Fields and Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-28 Setting Up Tabs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-29 Splitting Windows into Panes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-30 Splitting the Tab into Vertical Panes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-31 Splitting the Tab into Horizontal Panes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-31 Changing the Contents of the Pane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-31

Chapter 6: Tubular Load Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1 Entering Design Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2 Specifying the Initial Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4 Defining Cementing and Landing Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4 Fields. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5 Defining the Starting Temperature Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-11

Specify Tool Passage Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-13 Defining Burst Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-15

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Selecting the Design Burst Loads and the External Pressure Profile . . . . . . . . . . . Defining the External Pressure Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Defining Burst Load Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Using the Multiple tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Viewing the Associated External Pressure Profile . . . . . . . . . . . . . . . . . . . . . . Specify Burst Load Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . View Burst Load Pressure Plots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Burst Design Load Line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6-16 6-16 6-17 6-17 6-19 6-20 6-22 6-23

Specifying Collapse Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-24 Selecting Collapse Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Selecting Different External Pressure Profiles for Each Load Case. . . . . . . . . . . . Defining Collapse Load Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Viewing Collapse Load Pressure Plots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Collapse Design Load Line. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6-24 6-25 6-25 6-26 6-27

Specifying Axial Loads Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-29 Defining Custom Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-30 Displaying the List of Existing Custom Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . Renaming a Custom Load. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Editing Custom Load Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Define the Pressure Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Including the Custom Load in the Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . Defining the Custom Load Temperature Profile . . . . . . . . . . . . . . . . . . . . . . . Viewing the Pressure Profiles Including the Custom Load . . . . . . . . . . . . . . .

6-30 6-31 6-31 6-31 6-33 6-33 6-35

Chapter 7: Graphical Design. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1 Performing an Automated Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2 Checking Burst Design Using the Burst Design Plot . . . . . . . . . . . . . . . . . . . . . . . . 7-2 Creating a Pipe Section. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3 Modifying a Pipe Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6 Comparing Burst and Collapse Design Checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-8 Checking Collapse Design Using the Collapse Design Plot. . . . . . . . . . . . . . . . . . . 7-8 What is the Collapse Design Load Line? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-9 What is the Pipe Rating Line? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-9 Adding a Section to Satisfy Design Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-11 Checking Axial and Service Load Profiles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-12


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Using the Axial Load Profiles Plot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Using the Axial Service Load Profiles Plots . . . . . . . . . . . . . . . . . . . . . . . . . . Using the Service Load Lines Plot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Checking Axial and Triaxial Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Using the Axial Design Plot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Using the Triaxial Design Plot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Using the Triaxial Design Limit Plot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Modify a Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7-13 7-14 7-15 7-16 7-16 7-18 7-22 7-23

Checking a Specific Casing Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-24 Compressional Load Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-25

Minimum Cost Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-27 Fields and Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Maximum Number of Sections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Minimum Section Length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cost of K-55 Steel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Minimum Cost Search . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Select API and Premium Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Define Premium Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7-27 7-27 7-27 7-27 7-29 7-30 7-32

Chapter 8: Analyzing Tabular Results and Reports . . . . . . . . . . . . 8-1 Input Data Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2 Tabular Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3 Viewing the String Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4 What is the Maximum Allowable Wear? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5

Reporting in the StressCheck™ Software and Microsoft Word . . . . . . . . . . 8-8 Generating StressCheck™ Software Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-8 Previewing and Printing StressCheck™ Software Reports . . . . . . . . . . . . . . . . . . 8-11

Chapter 9: Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1 StressCheck™ Software Exercise Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-2 Exercise 1: Reviewing/Creating the Data Hierarchy. . . . . . . . . . . . . . . . . . . . . 9-4

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Exercise 2: Preferences and Workspace Configuration . . . . . . . . . . . . . . . . . . 9-5 Exercise 2 Answers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-7

Exercise 3: Reviewing/Specifying General Data . . . . . . . . . . . . . . . . . . . . . . . 9-14 Exercise 3 Answers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-17

Exercise 4: The Design Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-23 Exercise 4 Answers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-28

Exercise 5: Minimum Cost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-53 Exercise 5 Answers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-54

Exercise 6: Analyzing Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-62 Exercise 6 Answers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-64

Exercise 7: Tables and Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-72 Exercise 7 Answers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-74

Exercise 8: Sensitivity Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-86 Special Pipe Tubular Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-86 Exercise 8 Answers: Special Pipe Tubular Properties . . . . . . . . . . . . . . . . . . . 9-91 Taper String Design Check. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-99 Exercise 8 Answers: Taper String Design Check . . . . . . . . . . . . . . . . . . . . . . 9-100 High Collapse Casing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-108 Exercise 8 Answers: High Collapse Casing . . . . . . . . . . . . . . . . . . . . . . . . . . 9-110

Exercise 9: Independent Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-114 Exercise 10: Template Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-115 Exercise 10 Answers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-116


ix

Contents

x


Chapter 1

Introduction What is the StressCheck™ Software? The Landmark® StressCheck™ software is an extraordinarily powerful and easy-to-use engineering tool for the design and analysis of casing strings. The StressCheck™ software was developed in cooperation with several major oil and gas exploration and production companies as one component of a next-generation system for well engineering. It is based on casing design principles that are well accepted and broadly employed in the industry. With the StressCheck software, sophisticated design methods can be routinely employed to develop minimum-cost, high-integrity casing design solutions with minimum expenditure of time and effort. The StressCheck software can be used to design casing strings that meet or exceed all relevant design criteria from top to bottom. The StressCheck software can yield significant savings in total casing costs by providing a variety of automated formulations for specifying realistic burst, collapse, and axial loads, rather than traditional worst-case maximum load profiles, and by optimizing the number and length of casing string sections. In some cases, as much as 40% can be saved in comparison to casing designs developed by conventional methods. With the Custom Loads feature, the StressCheck software also provides an easy-to-use spreadsheet facility for specifying, in exact detail, user-defined internal pressure, external pressure, and temperature profiles when more unique load-case formulations are required. Experienced engineers who understand the requirements of casing design developed the StressCheck software with features that facilitate thorough consideration of more sophisticated design issues. These issues include: •

Running, installation, and service loads, for more comprehensive axial design

•

Gas kick loads

•

External pressure profiles for good and poor cement


1-1

Chapter 1: Introduction

•

Permeable zones

•

Mud density deterioration

•

Annulus mud drop

•

Worst-case or user-entered temperature profiles

•

Temperature-dependent and pressure-dependent gas-density profiles

•

Overpull limits

•

Allowable wear

•

Pressure testing

•

Automated Minimum Cost API or triaxial design

The StressCheck software offers OLE to Microsoft™ Office applications such as Word, Excel, and PowerPoint, as well as other OLE-compliant products. The StressCheck software includes powerful and flexible unit systems, both standard (API and SI) and user-defined, which make it easy to customize input and output unit conventions to suit virtually any international need. The StressCheck software can be used in combination with the powerful Landmark WELLCAT™ package to solve the toughest design problems.

Course Objectives During this course you should become familiar with:

1-2

•

Fundamental casing design principles

•

Equations used to calculate casing ratings

•

Design criteria and data entry

•

Casing design and design checks

•

Documenting and analyzing results



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 the StressCheck software. If you require more technical information than what is presented in this manual, please ask your instructor. The training course begins with a quick introduction. Following the introduction, time is spent covering the theory, concepts, and features used in the StressCheck software.

Licensing For information regarding Licensing, please refer to the Help > Engineer’s Desktop Drilling Summary Level Release Notes > Licensing.


1-3


1-4


Chapter 2

Theory, Calculations, and References This section covers the fundamental theory basis for StressCheck™ software calculations and includes the design methodologies considered for workflows.


2-1

Chapter 2: Theory, Calculations, and References

Casing Design Methodology The following displays a list of StressCheck features in a basic workflow that follows a casing design methodology.

2-2




2-3


Wellbore Temperatures and Casing Design Temperatures affect casing design in the following ways: •

Influence pressure loads (PVT properties of gas)

•

Decrease the pipe rating (the yield strength is a function of temperature)

•

Result in axial thermal growth, which can lead to buckling in uncemented sections and may require triaxial analysis to determine combined loading effects

•

Affect cement slurry design

•

Result in annular pressure build-up

•

Influence corrosion

Temperature Deration A default schedule is provided in the StressCheck software that is based on a linear deration of 0.03% per degree °F. Temperature

Yield Strength

Fahrenheit (°F)

Celsius (°C)

Correction Factor

68

20

1.00

122

50

0.983

212

100

0.956

302

150

0.929

392

200

0.902

Wellbore temperatures during drilling, completion, production, and workover operations can vary considerably from the undisturbed profile. The StressCheck software uses worst-case estimates by default. To accurately predict wellbore temperatures, a thermal simulator such as the WELLCAT™ software is required.

2-4



Drilling Temperatures For drilling load cases such as a gas kick or lost returns with mud drop, the profile used to correct the design load line is based on the calculated API circulating temperature and a straight line drawn through the midpoint of the user-entered undisturbed temperature profile.

Drilling Temperature Profile

Undisturbed Temperature Profile

Depth

Mid-point of Undisturbed Profile

API Circulating Temperature Temperature

The calculation of the API circulating temperature is generally overconservative. If a more accurate profile is necessary, thermal simulation using WELLCAT - Drill should be used.


2-5


Production Temperatures For production load cases such as a tubing leak, the profile used to correct the design load line is based on maximum undisturbed reservoir temperature at the perforation depth from TD to the surface.

Depth

Production Temperature Profile

Undisturbed Temperature Profile

Temperature

This profile is generally over conservative depending on reservoir fluid, flow rates, and time after initial production. If a more accurate profile is necessary, thermal simulation using WELLCAT - Prod should be used.

2-6



Initial Conditions The temperature used in the StressCheck software does not necessarily lead to more conservative design. This data is used to define load cases, determine the initial state of the casing, and dictate design and analysis logic. Surface Ambient dT

UNCONSERVATIVE SCK

StressCheck Actual

injection temp

production temp

Depth

TOC

Actual StressCheck SCK

Temperature Initial conditions data is defined on a per-string basis; that is, different initial conditions data can be defined for each string in the Casing Scheme spreadsheet.


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Surface Ambient

After WOC

WellCat StressCheck

injection temp

production temp

Depth

TOC

WellCat StressCheck

Temperature The WELLCAT software can simulate a more accurate temperature profile for both production and injection, which can lead to a less conservative design criteria.

2-8



Basic Material Properties To define a material, the Young’s Modulus, Poisson’s Ratio, and density must be specified. Young’s Modulus (ratio of stress and strain) and Poisson’s Ratio (ratio of lateral contraction to elongation) are the two independent parameters that describe the mechanical behavior of an elastic material.

Stress • • •

The symbol for stress is: σ Stress is defined as: Load / Cross-sectional area You can compare stress with: Pressure = Force/Area

•

The symbol for strain is: ε

•

Strain is defined as: Change in Length / Initial Length

Strain

or •

You can define True Strain as: Ln (Final Length / Initial Length). True strain accounts for the material volume.

Modulus of Elasticity (Young’s Modulus) The symbol for Modulus of Elasticity is E . For any material, E is a constant which relates stress and strain as long as they are proportional. (that is, a straight line graph).

E = σ⁄ε


2-9


Yield Strength (Tensile) Yield strength is the stress above which irreversible plastic deformation occurs.

2-10



Pipe Ratings Axial, Burst, and Collapse loads are factors that directly affect the performance ratings for the selected pipe or connection. Other factors that affect pipe ratings include reduced wall thickness and tension due to bending.

Axial The axial strength of the pipe body is determined by the pipe body yield strength formula found in API Bulletin 5C3. Axial strength is the product of the cross-sectional area and the yield strength. Nominal dimensions are used. 2 π 2 F y = --- ( D – d )Y p 4 Where: Fy = pipe body axial strength, lb Yp = minimum yield strength of the pipe, lb/in2 D = nominal outside diameter, inches d = nominal inside diameter, inches


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Burst The following equation is commonly called the Barlow Equation and is applicable to thin wall pipes. It assumes that burst is imminent when the pipe begins to yield. The factor 0.875 appearing in the equation allows for minimum acceptable wall thickness due to piercing operations as per API specification 5CT.

2Y p t P = 0.875 ----------D Where: P = minimum internal yield pressure, lb/in2 Yp = minimum yield strength of the pipe, lb/in2 t = nominal wall thickness, inches D = nominal outside diameter, inches

Collapse

As per API Bulletin 5C3, collapse criteria consists of four collapse regimes. These regimes are determined by yield strength and D/t. Most oil field tubulars experience collapse in the plastic and transition regimes. Nominal dimensions are used in the collapse equations. Collapse strength is primarily a function of the material’s yield strength and the D/t ratio. Collapse strength as a function of D/t is shown in the preceding graphic.

2-12



Yield Strength Collapse Yield strength collapse is based on yield at the inner wall using the Lamé thick wall elastic solution.

(D ⁄ t) – 1 P Y = 2Y p ----------------------2 p D  --- t Where: t = nominal wall thickness, inches D = nominal outside diameter, inches Yp = minimum yield strength of the pipe, lb/in2 Plastic Collapse Plastic collapse is based on empirical data from 2,488 tests.

A P p = Y p ---------- – B – C D⁄t –5

A = 2.8762 + ( 0.10679 ×10 )Y P + ( 0.21301 ×10

– 10

2

)Y P – ( 0.53132 ×10

– 16

3

)Y P

–6

B = 0.026233 + ( 0.50609 ×10 )Y P –7

2

– 13

C = – 465.93 + 0.030867Y P + ( 0.10483 ×10 )Y P – ( 0.36989 ×10

3

)Y P

Where: t = nominal wall thickness, inches D = nominal outside diameter, inches Yp = minimum yield strength of the pipe, lb/in2


2-13


Transition Collapse Transition collapse is a numerical curve fit between the plastic and elastic regimes.

F P T = Y p ---------- – G D⁄t

B 3 3 --A 6 46.95 ×10 -----------------B 2 +  ---  A F = ---------------------------------------------------------------------------------------2B  3 B ---  3  ---  A   A  B Y P ------------------ –  --- 1 –  ------------------ B  A 2 + B ---  2 +  ---   A   A B G = F --A Where: t = nominal wall thickness, inches D = nominal outside diameter, inches Yp = minimum yield strength of the pipe, lb/in2 (A and B are defined in the section on Plastic Collapse.)

Elastic Collapse Elastic collapse is based on theoretical elastic collapse. This criteria is independent of yield strength and applicable to very thin wall pipe. 6

46.95 × 10 P E = ---------------------------------------------2 (D ⁄ t)((D ⁄ t) – 1)

2-14



Where: t = nominal wall thickness, inches D = nominal outside diameter, inches

Diameter to Wall Thickness Regions The four API collapse regimes depend on the diameter to wall thickness (D/t) ratio of the pipe of interest. Therefore:

Yield Collapse D D ---- ≤  ----  t   t  YP

Plastic Collapse D D D ---- <  ---- ≤  ----  t  YP  t   t  PT

Transition Collapse D D D ---- <  ---- ≤  ----  t  PT  t   t  TE

Elastic Collapse D D ---- >  ----  t   t  TE Where: 1 --2

D ----  t  YP

C 2 ( A – 2 ) + 8  B + ------ + ( A – 2 )  Y P = ----------------------------------------------------------------------------------C 2  B + ------  Y P


2-15


YP ( A – F ) D ---- = ---------------------------------- t  PT C + YP ( B – G ) B 2 + --A D = ----------------  t  TE B 3 --A (A, B, C, F, and G are defined in the sections discussing Transition and Plastic Collapse.)

Effect of Tension on Collapse The biaxial effect of tension is incorporated in design by reducing the design rating of the pipe. The reduced yield strength equation is based on the Hencky-Von Mises maximum strain energy of distortion theory of yielding or triaxial analysis. In this case, the radial stress is ignored. This theory only applies to elastic yield failure (the yield collapse regime), but the reduction is applied to all the collapse regimes. This tends to be a conservative assumption. The collapse rating is not increased with compression.

Y pa =

Sa  S a 2 1 – 0.75  ------ – 0.5 ------ Y p Yp  Y p

Where: Ypa = yield strength of axial stress equivalent grade, lb/in2 Yp = minimum yield strength of the pipe, lb/in2 Sa = axial stress, tension is positive, lb/in2 Effect of Internal Pressure on Collapse The biaxial effect of internal pressure (radial stress) is incorporated in design by increasing the design rating of the pipe. The API chose to increase the apparent applied collapse pressure instead of including P0 and P1 in the collapse formulations. (They are only a function of ΔP). For all collapse loads, Pe >= DΔP

2-16



This relationship can be derived for Hencky-von Mises and Lamé, if higher order terms are ignored.

2 2 P e = P o – 1 – ---------- P i = ΔP +  ---------- P i  D ⁄ t D⁄t Where: t = nominal wall thickness, inches D = nominal outside diameter, inches Pe = equivalent external pressure, lb/in2 Po = external pressure, lb/in2 Pi = internal pressure, lb/in2 ΔP = Po- Pi To provide a more intuitive understanding of this relationship, the equation can be rewritten as: PeD = PoD - Pid Where: d = nominal inside diameter, inches

Pi

Po



P=0


Pe

2-17


Reduced Wall vs. Nominal Dimensions

Axial uses nominal dimensions. The piercing process during manufacture may result in non-uniform wall thickness, but the cross-sectional area of the pipe will remain constant. The equation used in API Bulletin 5C3 to define the axial rating is based on the product of the cross-sectional area and the yield strength. Burst uses minimum section. This represents a permissible 12.5% wall loss due to acceptable tolerances in the piercing and rolling process of manufacturing seamless pipe. (API Spec. 5CT). Collapse uses nominal dimensions. The API formula for plastic, transition, and elastic collapse have been adjusted using regression analysis to account for API tolerances. No adjustment has been made in the yield strength collapse regime.

2-18



Tension due to Bending Bending loads are superimposed onto the axial load distribution as a local effect. The bending load formulation is included in all axial load cases. Bending “force” is a convenient representation for design. Bending stress is a function of the local radius of curvature in the string component. Stress at the pipe’s outer diameter due to bending can be expressed as:

ED σ bending = -------2r Where: σbending = stress at the pipe’s outer surface E = elastic modulus D = nominal outside diameter r = radius of curvature Expressed as a force in English units, this can be simplified to: Fbending = 7.272 x 10-6EDφAs Where: Fbending = bending force, lb φ = dogleg severity (o/100 ft) D = nominal outside diameter, inches As = cross-sectional area, in2 E = Young’s Modulus, lb/in2 For steel pipe where E = 30 x 10-6 lb/in2, then: Fbending = 2186DφAs


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Triaxial Stress Analysis Triaxial stress is not a true stress. It is a way of comparing a generalized three-dimensional stress state to an uniaxial failure criteria (the yield strength). The triaxial stress is often called the von Mises equivalent (VME) stress. If the triaxial stress exceeds the yield strength, a yield failure is indicated. The triaxial safety factor is the ratio of the material’s yield strength to the triaxial stress.

Von Mises Equation 2 2 2 1⁄2 1 Y p ≥ σ VME = ------- [ ( σ z – σ Θ ) + ( σ Θ – σ r ) + ( σ r – σ z ) ] 2 Where: Yp = minimum yield strength of the pipe, lb/in2 σVME = triaxial stress σz = axial stress σθ = tangential or hoop stress σr = radial stress

2-20



Triaxial Design Ellipse Plotting the loads on this ellipse allows a direct comparison of the triaxial criteria with the API ratings. Loads that fall within the design envelope meet the design criteria.

Region of non-conservative uniaxial design

Region of more efficient design

Triaxial limit not applicable in Collapse region

Combined compression and burst loading corresponds to the upper left quadrant of the design envelope. This region is where triaxial analysis is most critical because reliance on the uniaxial criteria alone would not predict several possible failures.


2-21


Combined tension and burst loading corresponds to the upper right quadrant of the design envelope. This region is where reliance on the uniaxial criteria alone may result in a design which is more conservative than necessary. For most pipes used in the oilfield, collapse is an instability failure independent of material yield. The triaxial criteria is based on elastic behavior and the yield strength of the material and hence, should not be used with collapse loads. The one exception is for thick wall pipes with a low D/t ratio, which have an API rating in the yield strength collapse region. This collapse criteria along with the effects of tension and internal pressure (which are triaxial effects) result in the API criteria being essentially identical to the triaxial method in the lower right quadrant of the triaxial ellipse for thick wall pipes. For high compression and moderate collapse loads experienced in the lower left quadrant of the design envelope, the failure mode is permanent corkscrewing due to helical buckling. It is appropriate to use the triaxial criteria in this case.

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Buckling All service loads should be evaluated for changes in the axial load profile, triaxial stress, pipe movement, and the onset and degree of buckling. Buckling will occur if the buckling force, Fbuckling, is greater than a threshold force, Fp, known as the Paslay buckling force.

F buckling = – F a + p i A i – p o A o Where: Fa = actual axial force (tension positive) pi = internal pressure po= external pressure

Fp =

4w ( sin Θ ) ( ( EI ) ⁄ r )

Where: w = distributed buoyed weight of casing θ = hole angle EI = pipe bending stiffness r = radial annular clearance


2-23


Casing Buckling in Oil Field Operations Buckling should be avoided in drilling operations to minimize casing wear. Buckling can be reduced or eliminated by: •

Applying a pickup force after cementation before landing the casing

•

Holding pressure while WOC (Wait-on-Cement) to pre-tension the string (subsea wells)

•

Raising the top of cement

•

Using centralizers

•

Increasing pipe stiffness

In production operations, casing buckling is not normally a critical design issue. However, a large amount of buckling can occur due to increased production temperatures in some wells. A check should be made to ensure that plastic deformation or corkscrewing will not occur. This check is possible by using triaxial analysis and including the bending stress due to buckling. In high temperature applications, the intermediate and surface casings should also be checked for possible buckling occurring. Permanent corkscrewing will only occur if the triaxial stress exceeds the yield strength of the material.

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API Connection Ratings Connection ratings for 8 round (STC and LTC) and buttress (BTC) casing connections are based on four failure criteria given in API Bulletin 5C3: •

Burst (Internal Yield) - The internal pressure which will initiate yield at the root of the coupling based on connection geometry and yield strength.

•

Leak - The internal pressure which exceeds the contact pressure between the connection’s seal flanks.

•

Fracture - The axial force which causes either the pin or coupling to fracture based on the ultimate tensile strength. This is not consistent with the pipe body axial strength, which is based on yield strength.

•

Jump Out - The axial force at which an 8 round pin “jumps” or “pulls” out of the box without fracturing. This criteria only applies to STC and LTC connections.

The StressCheck software always reports the minimum safety factor based on pipe body or connection. If the connection is limiting the design, then the criteria with which the API connection fails will be presented. This does not indicate that the connection is failing to meet the failure criteria, but purely that it is the limiting part on the tubular. An example of a string summary is shown below: Production Casing

Burst

Collapse

Axial

Triaxial

9 5/8”, 47.00, N-80 STC

1.47

2.61

1.45J

1.48

9 5/8”, 53.50, N-80 LTC

1.77

1.68

2.13J

1.61

9 5/8”, 58.40, P-110 BTC

2.18L

1.28

5.03

1.80

L: Leak J: Jump Out


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Preliminary Design The largest opportunity for cost savings can be achieved during this stage of the well design. Preliminary design includes: • • • •

Data gathering and interpretation Determination of shoe depths and number of casing strings Selection of hole and casing sizes Mud weight and top of cement (TOC) design

Why Should You Do A Preliminary Design? The Landmark® CasingSeat™ software can offer the drilling engineer a selection of optimal casing ODs and setting depths based on geological, lithological properties and various drilling operations conditions. • • •

The design can be used as input data for detailed design (cannot yet order casings). Maximum savings are achievable at this stage. Standard designs (received wisdom) can be challenged.

What Data is needed to perform a Preliminary Design? • • • • •

Number of casing strings Pipe diameters Hole sizes Shoe and hanger depths Cement tops and mud program

Minimum Casing Diameter Driven by well operational requirements: • • • • •

2-26

Required well configuration Reservoir description Completion design Tubing size Minimum production casing/liner



Minimum Casing Shoe Setting Depth • • • • • •

Isolate overlying unstable formations Isolate overlying shallow hydrocarbons Isolate overlying lost circulation (‘thief’) zones Isolate overlying fresh water horizons Prevent failure of formations by induced circulating pressures during drilling operations Prevent failure of formations by induced circulating pressures during well control when closing in and circulating out an influx


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Detailed Mechanical Design Design loads represent the worst case loads that a particular casing string could experience during the life of a well.

Burst Loads Drilling Loads

Displacement to Gas This drilling load case models displacement of the drilling mud in the casing by gas. It applies only to burst design. Gas Gradient

Limit load case by the fracture pressure at the shoe. Fracture pressure at the shoe. Pore Pressure Internal Casing Pressure

2-28


Influx depth


By default, the gas column extends from the shoe depth (above open hole TD) to the wellhead, but you can specify the depth of a gas/mud interface, where the mud column is on top of the gas column. This load case represents a shut-in condition following a large kick. It is commonly used as a worst-case burst criterion for protective (intermediate) and surface casing. It is sometimes described as the “maximum anticipated surface pressure,” or MASP. Load and the load-case formulation is consistent with so-called “maximum load” casing design principles. The internal pressure profile is based on a mud density, a gas gradient, and the pore pressure at the influx depth. It is normally constrained by the fracture pressure at the shoe above the open hole TD. If you do not want to limit the internal pressure to the fracture pressure at the shoe, deselect the Limit to Fracture Shoe check box in the Tabular > Design Parameters > Analysis Options tab.

Gas Kick Profile This drilling load case creates an internal pressure profile that simulates the maximum pressures imposed on the current string while circulating a gas kick to the surface. This “limited kick” burst criterion is less conservative than the full Displacement to Gas load case. It applies only to burst design.

The internal pressure profile is determined based on specification of a kick volume and intensity at a kick depth, where kick intensity is the difference between the EMW for the kicking interval and the mud density in the open hole interval from whence the gas kick evolves. It is


2-29


normally constrained by the fracture pressure at the shoe above the open hole TD. If you do not want to limit the internal pressure to the fracture pressure at the shoe, deselect the Limit to Fracture at Shoe check box in the Tabular > Design Parameters > Analysis Options tab.

Fracture @Shoe w/ Gas Gradient Above This drilling load case applies only to burst design and commonly used as a worst-case burst criterion for protective (intermediate) and surface casing. This drilling load case models a shut-in well, after taking a large kick, where the formation fracture pressure at the shoe depth for the string above the open hole interval from whence the kick evolves is exceeded, and the mud in the casing is completely displaced by gas. The internal pressure profile is based on a gas gradient and the fracture pressure at the shoe above the open hole TD. This load case is very similar to the Displacement to Gas load case, except that pressure at the shoe above the open hole TD is always controlled by the fracture pressure. The Displacement to Gas load case is normally only controlled by fracture pressure if the calculated pressure at the shoe above the open hole TD exceeds the fracture pressure.

Fracture @ Shoe w/ 1/3 BHP at Surface This drilling load case applies only to burst design where drilling load case models a shut-in well, after taking a kick, where the formation fracture pressure at the shoe depth for the string above the open hole interval from whence the kick evolves is exceeded. The pressure at the surface is taken to be equal to 1/3 of the pore pressure at the open hole TD. This construct for burst design is based on observation in the Gulf of Mexico that pressures greater than 1/3 bottom hole pressure (BHP) are infrequently seen at the surface. The internal pressure profile for the load case is linear between the surface pressure and fracture @ shoe

2-30



boundary conditions. This load case is less conservative than the Displacement to Gas and Fracture @ Shoe w/Gas Gradient Above load cases.

Lost Returns with Water This drilling load case models a condition of partial or full loss of subsurface well control where, following a kick event and consequential loss of circulation at the shoe above the open hole TD, water is displaced down the casing-drillstring annulus in an attempt to avoid further deterioration of hydrostatic well control, to a condition of frac @ shoe and water to surface, by maintaining the highest-possible fluid level in the annulus. It applies only to burst design.

The internal pressure profile is determined from the fracture pressure at the shoe above the open hole TD, and water in the annulus.

Surface Protection (BOP) This drilling load case is used as a criterion for the design of surface pressure control (BOP) equipment and the upper portion of the casing and applies only to burst design of casing strings (not available for liners). The Surface Protection (BOP) load case is based on full displacement to gas, with a surface boundary condition equal to the surface pressure that would result from fracture pressure at the shoe above the deepest open hole interval for which the current string is exposed to drilling loads and a seawater gradient back to surface (that is, the default construct for the Lost Returns with Water load case). This load case develops relatively high design pressures at shallow depths, but is less conservative than Lost Returns with Water or Displacement StressCheckTM Software Release 5000.1.13 Training Manual

2-31


to Gas while providing a more conservative design pressure at shallow depths than that which would obtain from the Gas Kick Profile load case. Casing designed using the Surface Protection (BOP) burst criterion would be expected to incur a ductile burst failure deep in the string before a shallow failure would occur. The internal pressure profile is computed from the fracture pressure at the shoe above the open hole TD, seawater density, and gas density (deriving from either gas gravity or gas gradient).

Pressure Test This drilling load case generates an internal pressure profile based on mud density, applied pressure at the wellhead, and an option for specifying a plug depth other than the shoe depth for the current string. If an alternative plug depth is specified, the applied pressure is only seen above that depth. This load case applies only to burst design.

Green Cement Pressure Test This drilling load case models an internal pressure test immediately after bumping the plug during a single-stage primary cementing. The cement, still acting as a fluid, does not yet serve as a constraint over the cemented interval against casing-string length changes due to the combination of piston and Poisson effects. This load case is available for both burst and axial design, and can be selected in both the Tabular > Burst Loads and Tabular > Axial Loads dialog boxes. To consider Green Cement Pressure Test as a load for axial design, the load case must be selected in the Tabular > Axial Loads > Select tab. This load case formulation includes a particular external pressure profile that is used irrespective of the external pressure profile selected on the Select tab, and irrespective of whether or not the Single External

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Pressure Profile check box is marked in the Tabular > Design Parameters Analysis Options tab for the current string. The values specified on the Tabular > Initial Conditions > Cementing and Landing tab are used to construct the external and internal pressure profiles that arise from fluid hydrostatics alone. The specified test pressure is applied down to the float collar depth (also specified on the Tabular > Initial Conditions > Cementing and Landing tab). A Green Cement Pressure Test is often performed to save operational time and to prevent the formation of a micro-annulus caused by applying a high-test pressure after the cement has hardened. This load case can also be used to increase the cemented-and-landed hang-off tension of casing landed with mandrel-type hanger systems (for example, in subsea wellheads), where the application of a pickup load prior to setting of slips is not feasible. In such cases, the test pressure must be maintained until the cement has developed sufficient compressive and bond strength to resist relaxation of test-pressure–induced axial strains on test-pressure release. Selecting this load case and specifying a test pressure generates the axial load distribution that develops, with the casing at the current-string shoe depth specified in the Casing Scheme spreadsheet, immediately after completing the cement job (top plug landed and cement still a fluid) and on applying a surface pressure. Since the casing string is not yet constrained from movement over the cemented length by hardened cement, the piston force resulting from the test pressure acting on the top plug causes a significant increase in the axial load. The following factors are considered: •

The specified test pressure, applied to the inside of the casing and acting on a cross-sectional area corresponding to the casing ID at the float collar depth, which is specified on the Tabular > Initial Conditions Cementing and Landing tab of the Initial Conditions dialog box.

•

The buoyed weight of the casing, based on the mud at shoe value specified for the current string on the Casing Scheme spreadsheet, and the displacement and cement slurry densities specified on the Tabular > Initial Conditions > Cementing and Landing tab.


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•

Wellbore inclination, which will only be considered if the Deviated check box is marked on the Wellbore > General > Options tab and a valid well trajectory is defined in the Wellpath Editor spreadsheet.

•

Any bending-related axial pseudo-loads due to dogleg severities defined in the Wellpath Editor or Dogleg Severity Overrides spreadsheets. These loads are superimposed on the axial load distribution as a local effect using the formulation presented in the Running in Hole load case description.

Drill Ahead This drilling load case captures temperature profile and updated internal mud density for various string types. This load case will represent mud weight up / mud weight down after casing landing for drilling a new hole section. This particular load is required for strings that are not fully cemented in order to quantify how much buckling would occur on the uncemented section (prevents casing wear). This case can be used for any string except the last string (exception is protective casing or liner). Selecting this load case to visualize internal pressure profile which is defined with the heaviest mud weight used to drill the next hole section while the drill string is inside the current casing string, plus an ECD (Equivalent Circulating Density) value.

Gas Over Mud Ratio This drilling load case illustrates the ratio of well control gas to drilling mud. This is a burst load case that is enabled for all casing strings associated to a next open hole section. The Gas Over Mud Ratio load case allows a user to define the gas over mud interface based on a wellbore fluid column occupied by drilling fluid, expressed as a fraction of the greatest open-hole TVD, measured from RKB (Rotary Kelly Bushing) or the hanger depth, to which the string is exposed to drilling loads.

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The internal pressure profile is based on mud density, a gas gradient, fracture pressure at shoe, fracture pressure margin, gas over mud ratio, gas/mud interface depth and the pore pressure at the influx depth (the default influx depth is the TD of the deepest open hole section associated to the string of interest). The gas property shall be defined based on gradient or gravity. This load case temperature profile (drilling temperature profile) is used as the basis for determining a temperature and pressure dependent gas compressibility factor using a modified Redlich-Kwong cubic equation of state, the internal pressure profile can (or may not be) contained by the deepest fracture at shoe of the current string or string associated to the current string.


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Production Loads

Tubing Leak This production load case applies only to burst design and models a surface pressure applied to the top of the production annulus as a consequence of a tubing leak near the wellhead. The internal pressure profile is based on produced (reservoir) fluid gravity (gas), or gradient (gas/oil) and reservoir pressure data (that is, pore pressure at the perforation depth specified in the Production Data dialog box).

Above the production packer, for which the depth is specified in the Production Data dialog box, the internal pressure profile is based on a surface pressure equal to the reservoir pressure minus the produced fluid’s hydrostatic pressure (from wellhead to perforation depth) applied to a packer fluid density entered in the Production Data dialog box. From the production packer down to the perforation depth, the internal pressure profile corresponds to that which would develop for full displacement of this section to the produced fluid (that is, reservoir pressure minus the produced fluid hydrostatic pressure from packer to perforation depth). From the perforation depth down to the well TD, the internal pressure profile is based on reservoir pressure applied to the selected packer fluid density.

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Stimulation Surface Leak This production load case applies only to burst design and models an injection pressure applied to the top of the production annulus as a consequence of a tubing leak near the wellhead during injection.

The internal pressure profile is based on produced (reservoir) fluid gravity (gas) or gradient (gas/oil) and injection pressure data. Above the production packer, for which the depth is specified in the Production Data dialog box, the internal pressure profile is based on a wellhead injection pressure specified on the Tubular > Burst Loads > Edit tab. It is applied to a packer fluid density entered in the Production Data dialog box. Below the production packer, the internal pressure profile corresponds to that which would develop for the wellhead injection pressure and wellhead-to-shoe displacement to the injection fluid.


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Injection Down Casing This production load case models the internal pressure profile resulting from an injection operation down the casing. Frictional pressure losses are ignored. It applies only to burst design.

Gas Migration This production load case models the effect of a gas bubble migrating upward in the annulus between the production casing and the protective casing. The gas is constrained against expansion as it rises unless the fracture pressure at the shoe for the protective casing is exceeded, and the gas bubble pressure and volume remain unchanged with upward migration. This load case applies only for burst design, and is only available for strings of name-type “Protective” and type “Casing” or “Tieback”. This “gas bubble inversion” results in reservoir pressure at the wellhead and can occur in a subsea completion where the outer annuli are permanently sealed at the wellhead. Gas migration behind production casing is normally as a result of primary cementing failure.

Collapse Loads Drilling Loads

Full/ Partial Evacuation This load case should be considered if drilling with air or foam. It may also be considered for conductor or surface casing where shallow gas is encountered. This load case would represent all of the mud being

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displaced out of the wellbore (through the diverter) before the formation bridged off.

Lost Returns with Mud Drop This drilling load case models evacuation of the casing due to lost circulation. It applies only to collapse design.

The internal pressure profile corresponds to a mud drop that can occur due to drilling below the shoe. This mud drop is calculated by assuming the hydrostatic column of mud in the hole equilibrates with a specified pore pressure at a specified depth. The default depth corresponds to the depth with a pore pressure resulting in the lowest EMW in the open hole section. For prospects where there is uncertainty about the pore pressure profile, a seawater or normal pressure gradient is often used to calculate the mud drop depth.


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Cementing The external pressure profile for this drilling load case is self-described, modeling the differential pressure due to the higher lead and tail cement slurry densities on the outside of the casing, from the top of cement (TOC) to the shoe, immediately after the cement is displaced. It is unaffected by external pressure profile selections made on the Tubular > Collapse Loads > Select tab. This load case applies only to collapse design.

If a displacement fluid is used that has a lesser density than the current-string value for Mud at Shoe in the Casing Scheme spreadsheet (for example, seawater), the addition to collapse loading is considered both above and below the top of cement (TOC).

Drill Ahead The Drill Ahead load case is explained earlier. (“Drill Ahead” on page 2-34)

Collapse Well Containment Screening Tool (WCST) This load case should be considered to determine if a well can be contained via a capping stack in the event of a worst case discharge scenario. The capping stack helps in bringing a well under control in case of a blowout. It is essentially a lighter, specialized version of a blowout preventer that uses similar components to stop or control the flow of oil and gas. The Collapse (WCST) load case applies to collapse design and is specified in the Tabular > Collapse Loads > Select tab. Loads Collapse (WCST) option must be checked to obtain a permit to drill in the Gulf of Mexico deep-water scenarios.

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Production Loads

Full Evacuation This production load case models total evacuation of the casing due to the complete loss of workover or packer fluid into the formation, a large drawdown of a low permeability or low pressure production zone, or gas lift operations. It applies only to collapse design.

The internal pressure profile corresponds to an air column whose density profile is calculated with a temperature-dependent and pressure-dependent compressibility factor. Despite the similarity of this load case to the Full/Partial Evacuation drilling collapse load case, it is included to account for worst-case production temperature effects.

Above/Below Packer This production load case represents a combination of internal pressure profiles above and below the packer that can occur during different operations. It applies only to collapse design. Above the packer during production, it is assumed that the casing will never see the fully evacuated pressures that can occur below the packer because the production annulus is never in pressure communication with the open perforations. In this case, the internal pressure profile consists of a hydrostatic gradient due to the packer fluid density above the packer and a fully evacuated profile below. However, during completion or workover operations where the workover or packer fluid is exposed to a depleted zone, a fluid drop may occur corresponding to the hydrostatic head of the fluid equilibrating with the depleted pressure at the perforations.


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This second scenario is modeled by specifying a reduced pressure at the perforations and enabling the fluid drop above packer. This load case uses the worst-case collapse pressures from both scenarios (that is, a partial evacuation above the packer and full evacuation below) and represents a less severe alternative to a full evacuation.

Gas Migration Unlike the burst version of this production load case, the collapse version uses a self-described external pressure profile regardless of which external pressure profile was specified on the Tabular > Collapse Loads > Select tab, and irrespective of whether or not the Single External Pressure Profile check box was marked. This load case applies only to collapse design. It is only enabled for strings whose Casing Scheme spreadsheet reads Production in the “Name” cell and either Casing or Tieback in the “Type” cell. An analogous load case applies to burst design. This load case models a gas bubble migrating upward in the annulus behind the production casing. Since the bubble is not allowed to expand unless the fracture pressure at the previous casing's shoe is exceeded (that is, the pressure is not bled off at the wellhead), the bubble's pressure and volume do not change as it migrates upward. This “gas bubble inversion” results in reservoir pressure at the wellhead and can occur in a subsea completion where the outer annuli are permanently sealed at the wellhead, allowing the operator no means to monitor or relieve pressure. Gas migration is normally caused by channels in the cement between the production casing and a permeable reservoir. The internal pressure profile is based on the packer fluid density. The external pressure profile corresponds to the reservoir pressure applied at the casing hanger depth to the annulus fluid hydrostatic head, but limited to the fracture pressure at the prior shoe. If you do not want to limit the internal pressure to the fracture pressure at the shoe, you can disable the Limit to Fracture at the Shoe option.

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Axial Loads Running and Cementing

Running in Hole - Avg. Speed This axial load profile does not represent a load distribution seen by the pipe at one particular time. Instead, it is constructed by calculating the maximum tension seen at each point on the casing string while running the casing in the hole. The maximum tension experienced by a joint of casing is normally the tension when picking up out of the slips immediately after making up the joint. The assigned axial pseudo-load arising from dogleg-induced bending stress can cause the maximum tension to occur at depths where local well curvature (dogleg severity) was defined in either the Survey Editor or Dogleg Severity Overrides spreadsheets. The following factors are considered: •

The buoyed weight of the casing, based on the Mud at Shoe value specified for the current string on the Wellbore > Casing and Tubing Scheme spreadsheet.

•

The wellbore inclination if a valid well trajectory was defined in the Wellbore > Wellpath Editor spreadsheet.

•

Any bending-related axial pseudo-loads due to dogleg severities defined in the Wellbore > Wellpath Editor or Wellbore > Dogleg Severity Overrides spreadsheets. These loads are superimposed on the axial load distribution as a local effect.

Overpull Force Selecting this load case and specifying an overpull force generates an axial load profile that reflects this incremental force above the current hookload when running the casing string in the hole. Like the Running in Hole load profile, this axial load profile does not represent a load distribution seen by the pipe at one particular time while running the pipe (that is, the overpull force is not just applied when the casing is on bottom). Instead, the case is considered at each stage of the running operation (that is, with the casing shoe at a range of depths from the surface to the setting depth).


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The load profile is constructed by using the maximum force seen at each point on the pipe during the entire running operation. If overpull force is not specified, this case is identical to the Running Load case with no shock loads. The following factors are considered: •

The overpull force is applied at the surface, with the stuck point always assumed to be the bottom of the string.

•

The buoyed weight of the casing, based on the Mud at Shoe value specified for the current string on the Wellbore > Casing and Tubing Scheme spreadsheet.

•

Wellbore inclination if a valid well trajectory was defined in the Wellbore > Wellpath Editor spreadsheet.

•

Any bending-related axial pseudo-loads due to dogleg severities defined in the Wellbore > Wellpath Editor or Wellbore > Dogleg Severity Overrides spreadsheets. These loads are superimposed on the axial load distribution as a local effect using the formulation presented in the Running in Hole load case description.

If an alternate axial design factor is specified on the Tubular > Axial Loads > Options tab, this design factor is also used as the criterion for determining the allowable overpull as a function of depth presented in the View > Tabular Results > Maximum Allowable Overpull table.

Pre-Cement Static Load This load case generates the buoyed axial load distribution with the casing at the current-string shoe depth specified in the Casing Scheme spreadsheet, just prior to performing the cement job. The following factors are considered:

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•

The buoyed weight of the casing, based on the mud at shoe value specified for the current string on the Casing Scheme spreadsheet.

•

A force in addition to casing buoyed weight applied at the surface over the entire string length. For this axial load case, the applied surface force must be a pickup (positive) force.

•

Wellbore inclination, which is only considered if the Deviated check box is marked on the Wellbore > General > Options tab and a valid well trajectory is defined in the Wellpath Editor spreadsheet.



•

Any bending-related axial pseudo-loads due to dogleg severities defined in the Wellpath Editor or Dogleg Severity Overrides spreadsheets. These loads are superimposed on the axial load distribution as a local effect using the formulation presented in the Running in Hole load case description. Note The applied force as defined in this 6 for Pre-Cemented Static Load is applied prior to performing the cement job from the surface to the bottom of the string. It is independent of the pickup force specified in the Cementing and Landing tab, which is only considered in axial design when Service Loads is selected on the Axial Loads > Select tab. Pickup force in the Cementing and Landing tab represents an incremental upward force (above static string weight) applied at the surface after the cement has hardened, and results in increased tension above the TOC depth.

Similarly, the applied force as defined in this dialog box for Pre-Cement Static Load is independent of the slackoff force landing data in the Cementing and Landing tab, which is only considered in axial design where Service Loads is selected on the Tubular > Axial Loads > Select tab. Slackoff force landing data in the Tubular > Initial Conditions > Cementing and Landing tab represents a reduction to the current string axial load profile (immediately after cementing) by lowering of the casing before landing in the wellhead assembly. This force results in reduced tension both above and below the TOC depth as specified for the current string in the Casing Scheme spreadsheet.

Post-Cement Static Load) This load case generates the buoyed axial load distribution with the casing at the current-string Shoe depth specified in the Wellbore > Casing and Tubing Scheme spreadsheet, immediately after performing the cement job.

Green Cement Pressure Test The Green Cement Pressure Test is explained earlier. (“Green Cement Pressure Test” on page 2-32)


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Service Loads

Ballooning / Reverse Ballooning due to burst / collapse loading Service Loads models axial loads caused by in-service drilling and production burst and collapse loads (selected on the Tubular > Burst Loads > Select tab and Tubular > Collapse Loads > Select tab) that occur after the casing string is cemented in place.

Load Lines A single load line of maximum burst and collapse differential pressures is generated. A burst load line example is shown below. It is formed from two load cases used as burst criteria.

Automatic Load Generation The StressCheck software calculates internal pressure profiles based on the user input. A common external pressure is also selected and calculated, which provides the StressCheck software with a set of differential pressures. For each load: Internal Pressure – External Pressure = Differential Pressure In the preceding example, two burst loads have been selected and differential pressure has been calculated. The upper section of the casing

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design is driven by the Displacement to Gas load and the bottom by the Tubing Leak load. A load line is then compiled of the maximum differential pressure at any depth. In this case, the load line will be made up of both load cases.

Design Factors To make a direct graphical comparison between the load line and the pipe’s rating line, the design factor must be considered. Design Factor = Minimum Acceptable Safety Factor.

PipeRating DF = SF min ≤ SF = ---------------------------------AppliedLoad Where: DF = Design factor (the minimum acceptable safety factor) SF = Absolute safety factor

Design Factor Selection Design factor selection is inextricably linked to the design method. •

The more conservative the design assumptions, the lower the design factor may be to result in the same level of risk.

•

The higher the load uncertainty, the greater the design factor (for example, all else being equal, exploration wells should be designed using higher design factors than development wells).

The three most important aspects of the design method that will have a direct effect on the appropriate design factor value are: •

Selection of load cases and the assumptions used with the load cases (for example, use of a limited kick criterion vs. a full displacement to gas, the kick volume and intensity used, whether bending due to doglegs or shock loads are considered, and so on).

•

The assumptions used to calculate the pipe’s load resistance or rating (for example, whether a nominal or minimum wall section is


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used and whether yield stress is derated as a function of temperature). •

How wear and corrosion are considered in the design.

Graphical Design

Multiplying the actual load line by the burst design factor results in the design load line.

The burst rating of 9 5/8” 40 lbm/ft N80 pipe exceeds the burst load line at all depths. Hence, the burst design criteria has been satisfied for the production casing.

Load Line Corrections Normally, you derate the casing rating by the Design Factor: Maximum Allowable Load = Design Pipe Rating / Design Factor Similarly, you can increase the load, which is how the StressCheck software handles it: Minimum Design Rating = Design Load x Design Factor Apart from the design factor, two other effects which impact the design can be considered in graphical casing design by increasing the load line:

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•

The reduction of collapse strength due to tension (a biaxial effect). The load line is increased as a function of depth by the ratio of the uniaxial collapse strength to the reduced strength.

•

The deration of material yield strength due to temperature. Like the effect of tension on collapse, the load line is increased by the ratio of the standard rating to the reduced rating.


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External Pressure Profiles Mud and Cement Mix-Water

The Mud and Cement Mix-Water external pressure profile is based on the mud density (current-string Mud at Shoe value in the Wellbore > Casing and Tubing Scheme spreadsheet) from the hanger to the top of cement (TOC), and the cement mix-water density (from current-string Tubular > Initial Conditions > Cementing and Landing tab) from the top of cement (TOC) to the shoe.

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Permeable Zones Poor Cement Disabled

This external pressure profile is based on the permeable zones data in the Wellbore > Pore Pressure spreadsheet, mud density (current-string Mud at Shoe value in the Wellbore > Casing and Tubing Scheme spreadsheet), top of cement (TOC), and the cement mix-water density (from the current-string Tubular > Initial Conditions > Cementing and Landing tab). To use this profile assuming the cement job is good, do not select the Poor Cement check box on the Tubular > Burst Loads > Edit or the Tubular > Collapse Loads > Edit tabs for external profile). The permeable zones considered in this external pressure profile formulation are those that lie between the shoe depths for the current and prior strings. If, in the Wellbore > Pore Pressure spreadsheet, no permeable zones are specified within this interval, the Permeable Zones profile is identical to the Mud and Cement Mix-Water profile. For a


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more detailed explanation of this external pressure profile, review the “Mud and Cement Mix-Water” on page 2-50.

Poor Cement Enabled – High Pressure Zone

This external pressure profile is based on the permeable zones data in the Wellbore > Pore Pressure spreadsheet, mud density (current-string Mud at Shoe value in the Wellbore > Casing and Tubing Scheme spreadsheet), top of cement (TOC), and the cement mix-water density (from the current-string Tubular > Initial Conditions > Cementing and Landing tab). To use this profile assuming the cement job is poor, select the Poor Cement check box on the Tubular > Burst Loads > Edit or the Tubular > Collapse Loads > Edit tabs for external profile). This profile is used when the permeable zones have a higher pressure than the surrounding formations. The permeable zones considered in this external pressure profile formulation are those that lie between the shoe depths for the current and prior strings. If, in the Wellbore > Pore Pressure spreadsheet, no

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permeable zones are specified within this interval, the Permeable Zones profile is identical to the Mud and Cement Mix-Water profile. For a more detailed explanation of this external pressure profile, review “Mud and Cement Mix-Water” on page 2-50.

Poor Cement Enabled—Low Pressure Zone

This external pressure profile is based on the permeable zones data in the Wellbore > Pore Pressure spreadsheet, mud density (current-string Mud at Shoe value in the Wellbore > Casing and Tubing Scheme spreadsheet), top of cement (TOC), and the cement mix-water density (from the current-string Tubular > Initial Conditions > Cementing and Landing tab). To use this profile assuming the cement job is poor, select the Poor Cement check box on the Tubular > Burst Loads > Edit, or the Tubular > Collapse Loads > Edit tabs for external profile). This profile is used when the permeable zones have a lower pressure than the surrounding formations.


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The permeable zones considered in this external pressure profile formulation are those that lie between the shoe depths for the current and prior strings. If, in the Wellbore > Pore Pressure spreadsheet, no permeable zones are specified within this interval, the Permeable Zones profile is identical to the Mud and Cement Mix-Water profile. For a more detailed explanation of this external pressure profile, review “Mud and Cement Mix-Water” on page 2-50.

Minimum Formation Pore Pressure TOC Inside Previous Shoe This external pressure profile is based on the pore pressure profile specified on the Wellbore > Pore Pressure spreadsheet, mud density, top of cement (TOC), and cement mix-water density. To use this profile, the top of cement (TOC) must be inside the previous casing. This profile is only available as a burst criterion for casing strings (not liners).

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The Minimum Formation Pore Pressure external profile always uses a pressure profile reflecting the EMW corresponding to the minimum pore pressure gradient in the open hole interval (that is, the interval below the prior shoe depth).

TOC in Open Hole (with and without Mud Drop Enabled) This external pressure profile is based on the specified pressure profile defined on the Wellbore > Pore Pressure spreadsheet, mud density, top of cement (TOC), and cement mix-water density. This profile assumes the top of cement (TOC) is in open hole. To allow the mud level to drop, the Allow Mud Drop check box should be selected on the Tubular > Burst Loads > Edit tab for the load case. From the Apply Minimum EMW in Open Hole drop-down list on the Tubular > Burst Loads > Edit tab, select Previous Shoe (default) or Top of Cement.

Discontinuity at TOC w/o Mud Drop (if TOC selected).

With Mud Drop enabled, hydrostatic pressure equates to EMW of Minimum Formation Pressure applied to prior shoe or at TOC.

This profile is only available as a burst criterion for casing strings (not liners). The options on the Tubular > Burst Loads > Edit tab are only available if the top of cement (TOC) is in open hole (that is, the interval below the shoe of the previous string).


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The Minimum Formation Pore Pressure external profile always uses a pressure profile reflecting the EMW corresponding to the minimum pore pressure gradient in the open hole interval (that is, the interval below the prior shoe depth, either applied from prior shoe depth or current top of cement (TOC)).

Pore Pressure w/ Seawater Gradient This burst external pressure profile is based on a seawater gradient from MSL to the mudline and a linear pressure profile from the pressure at the mudline to the pore pressure at the shoe depth for the current string.

Linear gradient connecting mudline pressure and pore pressure at shoe of current string.

Pore pressure at casing shoe

If this profile is selected for an onshore well, the profile simplifies to a linear pressure profile from 0 psig at MGL (Mean Ground Level) to the pore pressure at the shoe depth for the current string. This external pressure profile has the greatest applicability for surface and conductor strings in offshore wells.

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Fluid Gradients w/ Pore Pressure This external pressure profile is constructed from a mud density above the top of cement (TOC), a fluid gradient from the top of cement (TOC) to the prior shoe (when applicable), and in open hole, either the fluid gradient below the top of cement (TOC) or the pore pressure profile.

This is the only external pressure profile available for Tieback strings.


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Mud and Cement Slurry This external pressure profile is based on the mud density from the hanger to the top of cement (TOC) and the cement slurry density from the top of cement (TOC) to the shoe.

It is identical to the external profile used with the Cementing load case, but it can be used with any of the other load cases. This is the most conservative external pressure profile and has the most applicability to operations associated with inner-string cementing jobs.

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Frac @ Prior Shoe with Gas Gradient Above This external pressure profile is constructed from the fracture pressure at the prior shoe, a gas gradient extending upward from that depth, and a mud gradient extending downward. It represents a worst-case collapse external profile where gas flow has occurred behind the casing.

Fracture pressure at prior shoe.

Mud gradient to current shoe.

Shoe/Mud Gradients w/ Pore Pressure This external pressure profile combines a mud weight pressure column if top of cement is at or shallower than prior shoe setting depth, a pressure discontinuity with an equivalent mud weight pore pressure gradient at the prior shoe setting depth, and pore pressure in the open hole. This profile supports two scenarios: •

Top of cement (TOC) below prior shoe depth

•

Top of cement (TOC) above prior shoe depth.

For offshore wells, this burst profile is based on a seawater gradient from MSL to the mudline, however 0 psig is used above sea level. StressCheckTM Software Release 5000.1.13 Training Manual

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For onshore wells, 0 psig is used above ground level (MGL). Below mudline or ground level, the profile used depends on the top of cement (TOC) for the current string.

If TOC is above the prior shoe: •

EMW pore pressure gradient between top of cement (TOC) and the top of the prior shoe is displayed (read only) on the Burst Loads > Edit tab.

•

Mud weight gradients above top of cement (TOC) are defined on the Tabular > Burst Loads > Edit tab.

•

Pore pressure profile below the prior shoe is defined using the Wellbore > Pore Pressure spreadsheet.

If TOC is below the prior shoe:

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•

EMW pore pressure gradient above the prior shoe is defined on the Burst Loads > Edit tab.

•

Mud weight gradients above TOC are displayed (read only) on the Burst Loads > Edit tab.

•

Pore pressure profile between the prior shoe and top of cement (TOC) is defined using the Wellbore > Pore Pressure spreadsheet.

•

Pore pressure profile below top of cement (TOC) is defined using the Wellbore > Pore Pressure spreadsheet.



Hydrostatic Isolation Depth This external profile is based on the Collapse Well Containment Screening Tool (WCST) load. Hydrostatic Isolation Depth (HID) is effectively the assumed top of good cement where hydraulic isolation is achieved in the annulus. HID is specified in the Tabular > Collapse Loads > Select tab. This profile supports two scenarios: •

Above the Hydrostatic Isolation Depth (HID), the Fracture Gradient at previous casing shoe and setting mud weight.

•

Below the Hydrostatic Isolation Depth (HID), the local pore pressure.


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Chapter 3

EDM™ and the Well Explorer Located by default on the left side of the application window, the Well Explorer functions much like the Microsoft Windows Explorer. Specifically, it is organized as a hierarchical data tree, and you can browse the EDM™ database at seven descending levels, though this varies between applications. This section familiarizes you with the basic Well Explorer functionality available in the StressCheck™ software.


3-1

Chapter 3: EDM™ and the Well Explorer

Overview In this chapter, you will become familiar with Landmark® software common features—the Engineer’s Data Model™ (EDM) database, and how the data structure is exposed via the Well Explorer. Currently, CasingSeat™ software, COMPASS™ software, OpenWells® software, StressCheck software, Well Cost™ software, WELLCAT™ software, and WELLPLAN™ software use the common database and data structure. In this section of the course, you will:

3-2

•

Learn about the EDM data structure, common data, data locking, and how to import and export data

•

Become familiar with the Well Explorer components and how to access data levels

•

Understand how datums are handled by the database

•

Learn about the Simultaneous Activity Monitor (SAM) and concurrent use of data in EDM

•

Learn how to access Catalogs from the StressCheck software



Describing the Data Structure Shown below, the EDM database hierarchical data structure supports the different levels of data required by drilling suite applications. Database Company

Hierarchical database structure of the EDM database.

Project Site Well Wellbore Design Case

Note The Case level applies only to the WELLPLAN software and is not discussed in this manual.


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The EDM database structure is exposed through a common Well Explorer, which is shared by drilling applications such as StressCheck (see the following figure).

Database level (filtered) Company level Project level Site level Well level Wellbore level Design level

Rig Contractors level

Templates Tubular Properties Catalogs

Well Explorer Components In addition to the Well Explorer “tree” previously shown, components of the Well Explorer (shown below) include the Filter, Recent Bar,

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Associated Data Viewer, and the Well Configuration and Reference Datum diagrams. Filter Shows currently selected filter (notice the “funnel” on the database node that indicates a filter is applied). It is used to provide a filtered look of the overall design. Recent Bar Shows the last selected data items; it is used to quickly open recently used items.

Hierarchical “Tree” The selected node shows the currently open Design.

Associated Data Viewer Components “associated with” the selected data item (the Design, in this example). Double-clicking on Pore Pressure, Frac Gradient, or Wellpath opens the respective editor on demand.

Well Configuration Diagram Shows the current Well configuration for the selected Design, including sidetracks for complex Wellbores.

Reference Datum Diagram Shows the current reference datum information for the selected Design.

For more information about the specific Well Explorer components and associated features, see the StressCheck Help.


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Working with the Well Explorer In this section, you will learn some basic operations performed with the Well Explorer. For a detailed list of all features available in the Well Explorer, see the StressCheck Help.

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 Projects, Sites, Wells, Wellbores, and Designs, as well as associated data items and attached documents. All drag-and-drop operations copy the data; data is never cut or moved. To copy data, drag-and-drop the item from one location and paste it into another. The item and all of its associated data are copied and pasted. You can drag and drop associated items (Wellpaths, Pore Pressures, Fracture Gradients, Geothermal Gradients, Hole Sections, Assemblies, and so on) into open Designs from the Associated Data Viewer at the base of the Well Explorer. The application automatically updates itself with the copied data. For more information, including the rules associated with drag-and-drop functionality, see the StressCheck Help.

Instant Design To access the Instant Design dialog box, select File > New > Instant Design; or right-click the Database level and select Instant Design from the drop-down menu. This dialog box allows you to quickly and easily create the hierarchy required to start a Design, from the Company to the

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Design. Instant Design allows you to enter minimal information rather than creating individual nodes for each level of the hierarchy.

Select the Company, Project, and Site from the pull-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 Design.

Specify datum information.

Import The Import command allows you to import selected data files in the StressCheck software. These files can either be transfer files in Extensible Markup Language (XML) format, StressCheck (SCK) format files or wellpath data files in text (TXT) format. Select File > Import > Transfer File or right-click the Database node in the Well Explorer and select Import from the drop-down menu. The Import dialog box opens. Enter the file name or browse for the file, and then click Open. The file is imported in the EDM database and contains the entire hierarchy (Company, Project, Site, Well, Wellbore, Design and any child data associated with the specific node). Select File > Import > SCK File to import StressCheck SCK files. The Import SCK File dialog box opens. Enter the file name or browse for the file, and then click Open. At this point, the data is available in the StressCheck software, but is not saved in the EDM database. Select File


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> Save to save the imported data as a Design in the database. The Save As… dialog box opens. Select a site for the Design, and specify a Design name in the New Design Name field. Click Save. The Well Explorer updates to display the Design. Select File > Import > WellPath to import and load delimited text wellpath data in the Wellbore > Wellpath Editor. The Import Wellpath File dialog box opens. Enter the file name or browse for the file, and click Open. The Wellpath data becomes available in the StressCheck software, but is not saved in the EDM database. Select File > Save to save the imported wellpath data. Note The Wellpath command is only available in the File > Import menu if a Design is open and the Wellpath is not read-only. For more information on importing Wellpath files, see “Import Wellpath File” on page 5-15.

Export The Export command allows you to export the selected node’s data in XML format. It also allows you to export the currently open Design in SCK (.sck) format. For exporting the Database, select the database node from the Well Explorer and select File > Export > Transfer File or right-click the Database node and select Export from the drop-down menu. The Export Library Transfer File dialog box opens. Enter a name for the file in the File name field, select the file type from the Save as type box and click Save. For exporting the Company and its associated data, select the company node from the Well Explorer and select File > Export > Transfer File or right-click the company node and select Export from the drop-down menu. The Export dialog box opens. Enter a name for the file in the File name field, select the file type from the Save as type box and click Save. Note You can export data at any level under the company node, using the method available for exporting Company data.

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For exporting a Design, open the Design and Select File > Export > SCK File. The Export SCK File dialog box opens. Enter a name for the file in the File name field and click Save.

Note The SCK File option is only available in the File > Export menu if a Design is open in StressCheck.

Attachments You can associate a folder or a file, such as a document, picture (Word, Excel, text file, JPG, and so on). Attached files can be of any type with a recognized extension. Folder attachments will open any accessible directory and display the contents of the folder. To access the


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Attachment Properties dialog box, right-click any data hierarchy node and then select New Attachment from the menu. Enter text that provides detailed descriptive information about the attachment.

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

Select the Save attachment as a link/shortcut only check box if you want to save the attachment as a link only. If you select this check 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.

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Well Explorer Node Properties Right-click any Well Explorer data node and select Properties from the drop-down menu to view or edit the selected node’s properties in a dialog box, such as the Company Properties dialog box shown below.

A brief description of data locking features is provided below. Details of the differences between the properties dialog boxes for each node, such as the specific tabs and content, is discussed in StressCheck Help.

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 must 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.


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By default, passwords are not set, and the Locked check box on all Properties dialog boxes can be toggled on and off with no security to prevent users from doing something they should not. 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 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 box for the company whose data you want to protect, there are two buttons, Company Level and Locked Data, and a Company is locked check box. 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. After the password is set, select the Company is locked check box 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 box, you are prompted to set a password. This password will then be 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 does not mean that anything below it is locked. After 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 box for the data level you want to lock and select the Locked check box. (For example, to lock a Wellbore,

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open the Wellbore Properties dialog box and select the Wellbore is locked check box.) Note When a design is locked, all associated items (Pore Pressure, Fracture Gradient, Geothermal Gradient, and Wellpath) are locked with it.

General Tab On the General tab of the Company Properties dialog box, the Company is locked check box and Locked Data and Company Level password buttons are discussed below. All Well Explorer node Properties dialog boxes, with the exception of the Database level, contain the “[Node Type] is locked” check box.

Company is Locked Check Box Select this check box to prevent editing of the Company data. If this check 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 deselect this check box.

Passwords •

Locked Data—Click this button to specify a password to lock all data associated with the Company, including all Projects, Sites, Wells, Wellbores, and Designs.

•

Company Level—Click this button to specify a password to lock only the Company data. The Company level password is only active if the Company is locked check box is checked.


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Click Locked Data to specify a password to lock all data associated with the Company.

Select the Company is Locked check box to prevent editing the company level data.

Click Company Level Locked Data to specify a password to lock Company data.

Audit Tabs In dialog boxes that contain the Audit Tab, information such as when the Company was created and last modified (and by whom) is displayed.

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Datums Datum terms are defined below and are grouped by the Properties dialog box in which they are found.

Project Properties The Project Properties dialog box contains a General tab in which you can specify System Datum and Elevation.

System Datum The System Datum 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, rig floor, RKB, and so on.

Elevation The Elevation represents the elevation above Mean Sea Level. (If Mean Sea Level is selected as the System datum, Elevation is grayed out.)

Well Properties The Well Properties > General tab is used to specify the Well name, Unique Well Identifier (UWI), and other descriptive properties of the well. You can also set tight group security, activate the unit system for the Design, and specify and define the Depth Reference datums.


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Depth Reference Datum(s) The Depth Reference Datum represents zero MD. It is sometimes known as the local datum, and it 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 (in the Well Properties dialog box). For each Depth Reference Datum, you must specify the elevation above or below the System Datum.

Elevations above, Depths below: [System Datum] This read-only label identifies the current System Datum. It also 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 pull-down list 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:

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•

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

•

Default - When selected, this check box indicates that this is the default datum. All Designs created below this Well inherit the default datum.



•

Elevation - Type, edit, or view the elevation above the System Datum (this must be a positive number). 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.

•

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

•

Date - Type the date on which 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 •

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 the Offshore check box deselected.

•

For an Offshore Well - If the Well is an offshore Well: — Select the Offshore check box 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).

•

For an Offshore Well that is Subsea - If the Well is an offshore Well subsea: — Select the Offshore check box. — Select the Subsea check box. (The Offshore check box must be selected 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)).


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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: •

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

•

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

•

Air Gap - This is the distance from ground level/sea level to the rig floor. It 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 box. Ground Level is set in the Well Properties > Depth Reference tab. 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. If you change the datum and it causes a negative air gap to be calculated, a warning message appears to inform 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 box).

•

Mudline TVD - (Offshore only) Display the distance from the Depth Reference Datum to the sea bed (datum Elevation + Water Depth).



Design Properties The Design Properties dialog box is used to specify a unique name for the Design. You can also select the Design phase, Depth Reference Datum for the Design and Lock the Design level data.

General Tab (Design Properties Dialog Box) Use this tab 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 box is used for informational and reporting purposes and is not required.

The following fields are present: In the Details section: •

Design - Type the name that will be used to identify the Design. The name must be unique. Note If the Design is locked check box is selected, you cannot edit any of the fields.


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•

Version - Type the version of the Design.

•

Phase - Select the phase of the Design from the pull-down list (Prototype, Planned, or Actual). The list of phases that appears 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 pull-down list 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 box will open. Use the arrow buttons on the calendar dialog box to move to the desired month, then click the day. The date you select populates the field. Click arrows to change to desired month. Click on the desired day

Depth Reference Information From the pull-down list of defined Depth Reference datums, select the datum you want to reference for this Design. After you select a datum, the Datum Elevation, Air Gap, current System Datum, Mudline Depth, and Mudline TVD are all recalculated and display the updated values adjacent to the rig elevation drawing on the Design Properties dialog box.

Workflow—How to Set Up Datums for a Design 1. Access the Project Properties > General tab and select the System Datum you want to use. 2. Access the Project Properties > General tab. 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 is negative. If your System Datum is Mean Sea Level, Elevation is grayed out.

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3. Access the Well Properties > Depth Reference tab. •

If the Well is offshore, select the Offshore check box and enter the Water Depth below the System Datum.

•

If the Well is subsea, select the Subsea check box and enter the Wellhead Depth below the System Datum.

4. Access the Well Properties > Depth Reference tab. If the Well is a land Well, make sure the Offshore check box is unchecked and enter the Ground Level elevation above the System Datum. 5. Access the Well Properties > Depth Reference tab. Define the Depth Reference Datum(s) you want to use, such as RKB or Rig floor. 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 > General tab, select the Depth Reference Datum you want to use for this Design from the pull-down list of datums you defined in Step 5.


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Changing the Datum 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 box, and you then attempt to open that Design, a warning message appears. 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 (details provided below). You are given the choice to open the Design in the original datum, or to convert to the new datum. If you choose to convert your data, the data is 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.

How This Works

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

If datum is different than the original datum If you open a Design in which the Depth Reference Datum (set at the Design level) is different from the original datum, the following occurs:

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•

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 and 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.

•

For Wells other than slant holes, the program issues 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 click 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 click Open, data is loaded to the original Design datum, but the Depth Reference Datum set in the Design does not change to match the original datum. — If you click Adjust, the 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 resolves the deltas in the first depths of column data (strings, wellpaths, columns, and so on) to adjust for the new gap and read zero depth on the first line.

Note After you open the Design, you should review your input data. Remember that the changes are not saved to the database until you explicitly save your data.


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Concurrency and Multi-user Support EDM supports full concurrency for multiple applications that are using the same data set. The SAM (Simultaneous Activity Monitor) server moderates the activity. This messaging server notifies a user of all data items currently open by other applications and users sharing the same database.

SAM in the Application Status Bar The SAM icon appears in the application Status Bar as follows: Message

Description A green SAM icon in the status bar indicates that the Messenger Service is active. If a tooltip is available, the message “SAM-Connected” displays. A green SAM icon with a red X in the status bar indicates that the Messenger Service is not currently active. If a tooltip is available, the message “SAM-Disconnected” displays. A red SAM icon in the status bar indicates the SAM service is enabled but has lost connectivity. Hover over the icon to display the tooltip “SAM - No longer responding”.

No icon

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



SAM in the Well Explorer If a data item is open, one of the following icons appears on the node icon. Icon

Description A red SAM icon indicates that one or more users on other PCs 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 database have this item open, but the current user still has full read-write access. A user must be careful when making changes to the data, though this method enables data to automatically flow between applications. Intentional updates to other live applications should be anticipated before saving changes.

The first user to open a data item becomes the data item’s owner. When another user opens the data item through an EDM application, that user can see that the data item is currently being accessed by the first user, who is the owner. Hover the mouse over the item to display a data listing tooltip as seen below.

RW indicates that the current user has read-write access. RO indicates that the current user has read-only access.


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Reload Notification A Reload Notification dialog box appears when the owner of the active data item saves changes to the database. SAM then notifies any other EDM applications of the changes. The Change Notification dialog box is then offered to the user to reload or ignore the data owner’s changes, or cancel the dialog box. The dialog box displays the user name for the owner and the application in which the changes were made. This enables the user to identify the source of the change that has been posted.

Reload The Reload option results in the owner’s changes being uploaded into the current application.

Ignore The Ignore option gives you the ability to ignore the owner’s changes and continue working with the current data item. You may choose to ignore the updates if you own the data item in another application. In this instance, you may choose to save later and overwrite changed data in the other application as a result. The user with read-only access to the data item may choose to ignore the owner’s changes in order to continue looking at the previous state of the data. The user may also perform a Save As operation to save the current data before reloading the changes. The WELLPLAN software does not support Save As functionality for read-only access.

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Select the Do not ask the question again check box to avoid receiving any other reload notifications. This check box option is not remembered between sessions. If you restart an application, you must select the check box the first time it appears in order to stop the appearance of the reload notifications.

Cancel The Cancel option gives you the opportunity to cancel the dialog box. If this option is selected, the Do not ask the question again check box is ignored. Complete details about SAM settings can be found in EDM Administration Utility Help.


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Working with Catalogs Catalogs are used as a selection list to design a casing, tubing, liner, or drillstring. Catalogs are editable and can be customized by using Start > Programs > Landmark Engineer’s Desktop 5000.1 > Tools > Catalog Editor or by right-clicking the catalog node and select Open from the drop-down menu. For more information, see the Catalog Editor Help.

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Chapter 4

Getting Started When you first enter the StressCheck™ software, a blank application window displays beneath the menu bar and toolbars. Normally at this point, you would either create a new Design or open an existing Design. However, particularly in multi-user environments, you may want to specify different data files (for example, report format files, default bit sizes, default design factors, default cost factors, or template files) to be used during this StressCheck session.


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Chapter 4: Getting Started

Workflow The workflow in the StressCheck software is broken up into three stages, which are outlined below.

Enter General Data

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•

Open the Design with which you want to work or create a Design using the Instant Design feature. (“Instant Design” on page 3-6)

•

Enter general information, including the well name, description, and total depth. (Wellbore > General) (“Enter General Data” on page 4-2)

•

Enter wellpath deviation (wellpath) data. (Wellbore > Wellpath Editor) (“Entering Wellpath Data” on page 5-14)

•

Enter dogleg overrides (imposed doglegs independent of deviation). (Wellbore > Dogleg Severity Overrides) (“Dogleg Severity Overrides Spreadsheet” on page 5-16)

•

Define the pore pressure regime. (Wellbore > Pore Pressure) (“Entering Pore Pressure Data” on page 5-8)

•

Define the fracture pressure regime. (Wellbore > Fracture Gradient) (“Entering Fracture Gradient Data” on page 5-10)

•

Optional: Define any squeezing salt or shale sections for collapse design. (Wellbore > Squeezing Salt/Shale) (“Defining a Squeezing Salt/Shale Zone” on page 5-12)

•

Specify the formation temperatures. (Wellbore > Geothermal Gradient) (“Defining the Geothermal Gradient” on page 5-19)

•

Define the Casing Scheme, including casing name, type, pipe ODs, hole size, shoe, hanger and TOC depths, and the mud weight at the shoe. (Wellbore > Casing and Tubing Scheme) (“Define the Casing and Tubing Scheme” on page 5-22)

•

Enter completion and production data. (Wellbore > Production Data) (“Defining Production Data” on page 5-28)



Specify Design Parameters for a Casing String •

Specify the design factors and other design parameters to use for the casing design. (Tubular > Design Parameters) (“Entering Design Parameters” on page 6-2)

•

Specify the maximum tool length for a specified tool OD that can freely pass through the casing. (Tubular > Tool Passage) (“Specify Tool Passage Requirements” on page 6-13)

•

Describe the cement and landing forces. (Tubular > Initial Conditions > Cementing and Landing tab) (“Specifying the Initial Conditions” on page 6-4)

•

Specify the temperature profile for the current string. (Tubular > Initial Conditions > Temperature tab) (“Specifying the Initial Conditions” on page 6-4)

•

Select standard load cases for burst, collapse and axial loads. (Tubular > Burst Loads, Tubular > Collapse Loads, Tubular > Axial Loads) (“Defining Burst Loads” on page 6-15, “Specifying Collapse Loads” on page 6-24, and “Specifying Axial Loads Details” on page 6-29)

•

Optional: Design additional custom loads. (Tubular > Custom Loads) (“Defining Custom Loads” on page 6-30)

View Graphical Results and Perform Design •

Review formation plots including pore pressure, fracture gradient, pore/fracture/mud weight, and geothermal gradient. (View > Formation Plots)

•

Review and analyze temperature profiles, pressure profiles, internal pressures and differential pressure plots for burst and collapse loads. (View > Burst Plots and View > Collapse Plots)

•

Review and analyze design load line, graphical interactive weight, and grade selection, including design review, graphical design, and minimum cost design. (View > Design Plots) (“Checking Burst Design Using the Burst Design Plot” on page 7-2, “Checking Collapse Design Using the Collapse Design Plot” on page 7-8, and “Checking Axial and Triaxial Design” on page 7-16)


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•

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Review and analyze advanced results, including triaxial design limit plot, and maximum allowable wear tables. (View > Triaxial Check and View > Tabular Results) (“Tabular Results” on page 83, “Checking Axial and Triaxial Design” on page 7-16)



Getting Started Starting the StressCheck™ Software Title Bar Work Area

Menu Bar Toolbars

Filter Recent Bar

Hierarchical “Tree”

Associated Data Viewer

Well Configuration

Reference Datum Diagram


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You can start the StressCheck software in two ways: •

Select the Windows menu path Start > Programs > Landmark Engineer’s Desktop 5000.1 > StressCheck.

•

Double-click the StressCheck desktop shortcut.

The first window to appear when you start the StressCheck software looks similar to the one in the previous graphic. At this time, few menu options are available and most of the toolbar icons are not available for use. You can select an item from the menu by using the mouse or the keyboard quick keys. To use the quick keys to select an item, press and hold the Alt key while pressing the underlined character in the menu item. For example, to open the File menu, press Alt-F. You must open an existing Design or create a new Design to expand the menu bar options or to activate additional toolbar buttons.

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Files and Templates What Type of Files Does the StressCheck™ Software Use?

File Extension

File Type Purpose

*.DXT

Data exchange (DEX) template file

*.DXD

Data exchange (DEX) import/export files

*.SCK

Well files created using the StressCheck software. Also called “flat files”.

*.SCT

Template files created using the StressCheck software

*.TXT

Data files for importing directional data

*.XML

Extensible Markup Language (XML) file used to transfer data

What is a Template File? Templates contain common data that can be used and reused as defaults for future casing designs. You can use templates as the basis for creating Designs. Default data can be entered and saved in the template to a file or to the EDM™ database. A template typically contains no specific well data or data that is dependent on depth. Templates are used to describe generic practices and parameters for general cases. For example, templates can be used to set up default load cases for specific casing string types typically used by an operating company. A special group of default data already exists, which is the definition of casing strings by name and type as specified in the Wellbore > Casing and Tubing Scheme spreadsheet. This information provides you with a selection of design limits, load cases (burst, collapse, and axial), as well as other tubular data. All combinations of casing strings can be defined in this manner and saved in the template.


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Some menu items and parameters are disabled when a template is defined. In template mode, no calculations are performed, so some results are displayed as “N/A”. Furthermore, some restrictions on accessing various dialog boxes and entering data do not apply in template mode. For example, you do not need to create pore pressure data and fracture gradient data to access Tubular > Burst Loads.

Opening an Existing Template File Templates can be opened from the EDM database or as a file from a local or network drive. Templates are applied only once, when initially creating or opening a Design, and cannot be reapplied. A company may provide templates to users to set policy for certain materials, inventories, casing schemes, and so on. Select File > Template > Open From File or File > Template > Open From Database to open an existing template file.

When opening a template file, navigate to the location and select from a list of existing templates

When opening a template from the EDM database, select from the pull-down list.

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Saving a Template File After you have opened and perhaps changed a template, you can save it with the same name or with a new name. By saving the template with a new name, you can create different templates to meet various requirements. All templates are saved to the EDM database. Select one of the following commands: •

File > Template > Save to save the template with the same name. No dialog box appears. The template is saved to the database.

•

File > Template > Save As to save the template with a different name as shown below.

•

File > Template > Save As System Template to save the template as a System Template that is available to all StressCheck users. The dialog box is the same one that appears for the File > Template > Save As command shown below. The Save As System Template command may not be available due to Company policy.

Specify the name of the template file.


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Main Window Layout The StressCheck main window is shown below. In this window, the well schematic is currently displayed. The main window is used to display data entry dialog boxes and spreadsheets. It is also used to display results. The main window has several distinct areas, as shown below. Most of these options do not become available until after you open a template file or Design. Name of open Design

Plot Toolbar

Wizard Toolbar

Template Toolbar

Menu Bar Main Toolbar Engineering Toolbar

Well Explorer Hierarchical “Tree”

Associated Data Viewer Well Configuration Diagram

Reference Datum Diagram

Tabs

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Work area with Well Schematic displayed


Status Bar


Title Bar The Title Bar is located at the top of the main window. The Title Bar displays the name of the active Design and the name of the active spreadsheet, table, plot, or schematic (if the active window is maximized).

Menu Bar After a Design has been opened or created, the menu bar has a number of options available.

File Menu The File menu has commands to manage files and templates, import Wellpath .txt files, import or export StressCheck .sck and Transfer .xml files, access DEX data transfer, send StressCheck .sck files via email, print documents, and exit the StressCheck software.

Edit Menu The Edit menu has commands used to undo changes; cut, copy, and paste information; manipulate OLE objects; view/edit spreadsheet properties; and find data in the Well Explorer tree.

Wellbore Menu The Wellbore menu is used to define data not related to a specific casing string, such as well depth; wellbore deviation; and pore pressure, fracture pressure, and geothermal gradients.

Tubular Menu The Tubular menu is used to define data related to a specific casing string, such as design parameters, cementing and landing data, string-section descriptions, connections, and load cases. This menu also manages inventory items used with the current Design, such as pipe inventory, special connections, and pipe grade properties.


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View Menu The View menu is used to display/hide the Well Explorer; display wellbore, load case, and design plots; and display tabular reports.

Composer Menu The Composer menu is used to add, edit, and configure Wall Plot objects. The commands are only available when a Wall Plot is active in the work area.

Tools Menu The Options menu is used to customize the StressCheck software (set up toolbars, status bars, tabs, defaults, options), and configure the unit system.

Window Menu The Window menu has commands to arrange and select windows.

Help Menu The Help menu has commands to access online Help and obtain information about the StressCheck software.

Wizard Toolbar The Wizard toolbar provides easy access to common data selection and form selection commands. It is used to select the current casing string. The Wizard provides you with a predetermined sequence of entry forms to help ensure that all necessary information is specified. Go to the previous form in the Wizard list of entry forms. Current data entry form. Go to the next form in the Wizard list.

All entry forms accessible using the Wizard can also be selected from the Wellbore and Tubular menus.

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Data Entry Forms The dialog box and spreadsheet are the two types of entry forms available in the StressCheck software. They may all be accessed from the Wellbore and Tubular menus, and most from the Wizard, depending on how you are entering the well data.

Dialog Box The first type of entry form is a dialog box, as seen in the example below. When selected, the dialog box opens over the current window contents. Dialog boxes are used to enter data such as design parameters and load cases that cannot be conveniently presented in a spreadsheet. All dialog boxes in the StressCheck software are modal, which means you cannot access any other spreadsheets or dialog boxes until the current dialog box is closed.


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The following control buttons may be found in dialog boxes: Select

To Update the well with the current changes and close the dialog box. Disregard any changes made since the last update and close the dialog box. Update the well with the current changes and keep the dialog box open. Display Help for the dialog box.

Spreadsheets The second type of entry form is the spreadsheet, as seen in the example below. When selected, it fills the current StressCheck window pane. Spreadsheets are used to enter depth and inventory data. Spreadsheets remain in view until they are replaced by another spreadsheet or view. Data is automatically applied when a further action occurs.

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Helpful Features Online Help The context-sensitive Help system can be accessed in several ways: •

Press F1 to view Help on the active spreadsheet, plot, table, or dialog box.

•

Select Contents from the Help menu.

•

Click the

•

Click the context-sensitive Help icon ( ) and then click on the portion of the window for which you desire Help (such as a toolbar icon or menu item). This feature is not available if a dialog box is open.

button on an open dialog box.

The Help Contents is shown in the following graphic. Click Back to go to the previous help topic.

Click Print to print the current help topic.

Select the tabs to view the Index and Glossary, Search the entire help system, or bookmark topics as Favorites.

Click Hide or Show to toggle on and off the Table of Contents.

Click a book to view the help topics associated with that item. Then click a help topic to view it.


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Setting Options Options are not stored as part of the active Design and affect all Designs analyzed with the StressCheck software until the options are changed. Select Tools > Options to access the Options dialog box. Control the appearance of printed documents.

Control the appearance of the graphical views.

Select MD or TVD to determine how depths are displayed in plots, spreadsheets, and tables.

Control the appearance of spreadsheets and tables.

Specify how safety factors display.

Control options for Permit to Drill report (APD).

Design Plots Group Box

Grid Select the Grid check box to display grid lines on all plots. These lines are used only as cues to help guide the eye when visually analyzing data.

Font Button Click the Font button to display the Font dialog box so you can change the font, style, and text size used along the axes of all plots.

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Markers Select the Markers check box to display individual symbols to denote each set of data displayed on all plots. Markers are usually drawn at known or well-defined points, while the envelope lines connecting these markers are generally interpolated.

Lines Button Click the Lines button to display the Lines dialog box so you can set the color and thickness for each line marking each set of data on every plot.

Legend Select the Legend check box for the appropriate legend to appear in all plots. When the legend obscures a relevant portion of the plot, click the legend and drag it elsewhere.

Font Button Click the Font button to display the Font dialog box so you can change the font, style, and size of text used in all plot legends.

Spreadsheets and Tables Group Box

Grid in Tables Select the Grid in Tables check box to draw grid lines and row labels on all results tables, such as the Well Summary table.

Font Button Click the Font button to display the Font dialog box so you can change the font, style, and size of text used in all spreadsheets and tables. Fonts for plots are customized by clicking the View Title Font button in the Other group box.


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Printing Font Button Click the Printing Font button to display the Font dialog box to specify the font used when printing spreadsheets and tables. It is useful for printing a small font on wide spreadsheets and tables.

Print Layout Group Box

Headers and Footers Select the Headers and Footers check box to display headers and footers when a document is displayed by using the Print or Print Preview commands. •

The file name displays in the upper left corner.

•

The date and time at which the document was displayed and the page number displays in the upper right corner.

•

The software version displays in the lower right corner.

•

The well’s description displays in the lower left corner.

Page numbers do not display when the Page Numbering check box is not selected.

Page Numbering Select the Page Numbering check box to display page numbers in the upper right corner of each page when a document is displayed by using the Print or Print Preview commands. This check box is disabled if the Headers and Footers check box is not selected.

Margins Select the Margins check box to add margins to the top, bottom, left, and right sides of each page when a document is displayed by using the Print or Print Preview commands. If this check box is not selected, the document is drawn out to the edges of every page.

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Depths Group Box

MD and TVD MD and TVD are a pair of mutually exclusive option buttons that determine whether depths in applicable plots, spreadsheets, and tables are displayed by using measured (MD) or true vertical depth (TVD). Alternatively, you can switch between depths by clicking the MD/TVD icon ( ) on the Engineering toolbar.

Safety Factors Group Box

Absolute and Normalized Safety Factors Absolute and Normalized are a pair of mutually exclusive option buttons that determine whether the safety factors reported in the various tabular results are absolute or normalized to the appropriate design factor. In essence, the normalized safety factor is the absolute safety factor divided by the design factor that is specified on the Design Parameters dialog box, or the design factor that is specified on the Options tab of the Tubular > Axial loads, Tubular > Burst loads, and Tubular > Collapse Loads dialog boxes. Alternatively, you can switch between safety factors by clicking the Normalized > Absolute Safety Factors icon ( ) on the Engineering toolbar.

MMS Report Group Box

Default Calculation Method Select the MASPfrac or MASPbhp option from the Default Calculation Method drop-down to calculate MASP values displayed in the MMS reports. You can also select the Default option to use the lesser MASP value of the two methods.

Default Depth Reference Point Select the RKB option to use the Rotary Kelly Bushing location as the Depth Reference Point. Select the Hanger option to use the pipe string hanger location as the Depth Reference Point.


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Other Group Box

Detailed Wizard List Select the Detailed Wizard List check box to add several dialog boxes, spreadsheets, and design plots to the standard Wizard list. When this check box is selected, the following items are added to the Wizard: • • •

Dogleg Severity Overrides Squeezing Salt/Shale Geothermal Gradient

View Title Font Button Click the View Title Font button to access the Font dialog box so you can change the title’s font, style, and size displayed in plot legends.

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Configuring Units Using the Unit System Dialog Box Select Tools > Unit System to add, remove, edit, and switch unit systems. You can also import and export custom unit systems. The unit system for the Design you are working on is stored at the Well level. All unit systems are stored in the database. The API, SI, API - US Survey Feet, and Mixed API unit systems are included with the StressCheck installation. Select the unit system you want to use in the analysis from the pull-down list.

Click Import to import a unit system. Click New to create a unit system.

The Unit Systems Editor dialog box always contains three or more tabs arranged along its upper left corner—one for each available unit system stored in the database. The three left-most tabs are always API, SI, and API - US Survey Feet. The Mixed API unit set is shipped with the StressCheck software, but it can be deleted. If you create custom unit systems, they are also present as tabs. When this dialog box is opened, the tab containing the unit system associated with the active Design opens. Most numerical dialog box 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.


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To look at the values for a different unit system, select another tab and click OK. To switch to another unit system, select the desired unit system from the Active Viewing Unit System pull-down list, and click OK. All open Designs are presented in this unit system. The Status Bar at the bottom of the main screen displays the name of the unit system that is currently in use. Unit system is set at the Well level and affects all Wellbores and Designs below it. For more information, refer to Unit System Help. CAUTION Be careful when you delete. Other users may want to use the unit system you are planning to delete.

Creating a Unit System To create a unit system: 1. Open the Unit Systems Editor dialog box by selecting Tools > Unit System. 2. Click New. 3. Enter a name for the unit system.

Select the basis for the unit system from the pull-down list.

4. Click OK. You can now choose from a large variety of unit options for all physical parameters used in the StressCheck software.

Using the Convert Unit Dialog Box With a spreadsheet cell selected, press F4 or select Tools > Convert Unit to enter or view data in any equivalent unit without changing the

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unit systems currently in use. Only the value in the active cell/field is affected. When you close this dialog box, any new numerical value chosen is written to the field, but the value is displayed in the unit system already in use. If you want a new unit system used, you must use Tools > Unit Systems, which changes the unit systems for all fields. To use the Convert Unit dialog box, a spreadsheet cell or a dialog box field that is editable must be selected, and it must have a value associated with a physical parameter (Tools > Unit Systems). For default values, the program displays the value appropriate for the units selected. The Convert Unit dialog box contains the following:

Value By default, this is the value displayed in the field or cell from which the Convert Unit dialog box was invoked. You can type or paste a new value into this cell, and it will be converted to the current unit system after you click OK.

Unit The Unit list box has the units in which the value can be expressed. Select the appropriate unit from this list and its value displays in the Value field. Note Be aware that when this dialog box is invoked, its name varies according to the cell selected. For example, when it is invoked from the Zone Top cell in the Squeeze Salt/Shale spreadsheet, the dialog box is titled Convert Depth Units. When it is invoked from the Overburden Pressure cell, it is titled Convert Pressure Units.

After you click OK, the dialog box closes, and the value is placed in the field or cell from which the Convert Unit dialog box was invoked. Before the value is placed, it is converted back to the units used by the active unit system. If the dialog box was invoked from a field or cell in which the Paste command does not work, the value is ignored. The Undo command can be used if a new value was entered.


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Example In the following example, the Mix-Water Density units are changed.

Click in the cell or field that you want to convert the units from. The Convert Unit dialog box displays. Select the new unit from the Unit list. View the converted value in the Value field.

1. Click a cell or field that contains the units you want to convert, from the active spreadsheet or dialog box. 2. Select Tools > Convert Unit, or press F4 to display the Convert Unit dialog box. 3. Select the desired unit from the Unit list. 4. View the converted value in the Value field.

Using the Convert Unit Dialog Box With a Design open, press F9 or select Tools > Convert Depth to calculate True Vertical Depth (TVD) from Measured Depth (MD) or vice versa.

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To calculate TVD from MD: 1. Enter a value in the ft MD field. 2. Click MD to TVD ->.

To calculate MD from TVD: 1. Enter a value in the ft TVD field. 2. Click <- TVD to MD.

Note The Convert Depth dialog box uses values from the Wellpath to convert MD to TVD and vice versa. If a Design does not contain Wellpath values such as Inclination or Azimuth, then Convert Depth will not calculate correct value.


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Customizing Graphical Views To change the properties of a plot or schematic, right-click the object when the plot or schematic is active. The choices available vary depending on the nature of the object.

Right-click on the plot, then select Properties.

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Changing Plot Properties All plots can be modified by right-clicking while a plot is active and then selecting Properties. The StressCheck software uses two plot engines. Each plot engine displays different properties dialog boxes, as seen below.

Older plot engine Properties dialog box

Newer plot engine Properties dialog box

For details about configuring plot display, see StressCheck Help.


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Zooming The older plot engine right-click menu features a Zoom facility. You can zoom in as many as 10 times to investigate specific features. A Restore feature allows the view to be restored to its last setup. Select the desired magnification.

Select Restore to return to the previous magnification.

Configuring the Well Schematic On the Well Schematic, the right-click menu Properties command allows the display of various markers on the schematic, including Cement, Tapered String, Reference Depths, Fluid, Casing Float Shoe, TOC for Liners and Casing Strings, TOL, and a Non-Deviated schematic view.

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Accessing and Managing Pipe Inventory When the Tubular > Pipe Inventory spreadsheet is accessed for the first time, it displays an inventory of casing for the OD corresponding to the OD designation in the Wellbore > Casing and Tubing Scheme spreadsheet for the string that is currently selected. The pipe inventory for a different OD can be selected using the Select OD pull-down list on the Template toolbar. The entire pipe inventory for all sizes can be displayed by selecting All at the top of this list box. Select the OD that you want to view data for using this selection list.

The pipe inventory is automatically sorted on the basis of the three keys specified in the Sorting dialog box. The default key settings are OD (primary), weight (secondary), and grade (tertiary) which are accessed from View > Sorting dialog box.

The Pipe Inventory Catalog (accessed by using the Edit > Import from Catalog and Edit > Export to Catalog commands when the current view is the Pipe Inventory spreadsheet) contains a built-in API catalog


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that contains all API casing, as listed in Table 1 of API Bulletin 5C2, as well as API line-pipe in the range of 22-42 inches OD.

Default performance properties for API line pipe are calculated on the basis of API Bulletin 5C3 formulations for internal yield pressure (burst), pipe body yield strength (axial), and collapse pressure. For collapse pressure ratings determined by this method, be aware that the API Bulletin 5C3 collapse pressure formulations are, in large part, empirically derived from testing on materials of greater minimum yield strength and tubes of lesser D/t (diameter-to-wall thickness) ratio than are typical of API casing. API does not recommend using the 5C3 collapse formulations for line pipe, but it does state in § 2.4 of 5C3 that “For line pipe having a yield strength and D/t falling within the limits of the sizes and thickness listed in API Specification 5CT, application of the formulas in 2.2 (the API collapse formulas) should yield reasonable estimates of minimum collapse pressure.” Sound engineering judgment is recommended when using these line pipe ratings. Each valid entry (or row) in the Tubular > Pipe Inventory spreadsheet defines a pipe that is available for manual, graphical, or minimum-cost design. To be considered a valid entry, every cell in a row, except “In Inven.”, must contain a legitimate value. By default, the initial contents

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of the Tubular > Pipe Inventory spreadsheet for a given Design are identical to the contents of the API catalog in the Pipe Inventory spreadsheet. However, immediately after the Design is created, supplemental entries can be made to the Pipe Inventory as required. Pipe Inventory entries that you want excluded from consideration in the Design can, and should, be deleted from the inventory. These inventory changes only affect available casing in the current Design, and the API catalog in a Design remain unchanged. Note The only Tubular > Pipe Inventory entries that cannot be modified or removed are those that are currently included in the design of one or more strings by virtue of their selection in a Tubular > String Sections spreadsheet. If you attempt to modify or remove them, the status bar displays the message “This pipe is in use and cannot be modified.”

Select the View > Selection dialog box to facilitate selecting casings you want removed from the current pipe inventory, or you want added to that used in a different Design. In the dialog box, specify an OD, one or more weights, and one or more grades, and then click OK. All pipe inventory entries matching the selection criteria are highlighted and can then be deleted or copied.

Selecting and Deleting Pipes The Selection dialog box is useful when deleting pipes from an inventory or when selecting multiple entries to be copied from one spreadsheet to another.


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Select View > Selection to access the Selection dialog box.

The Selection dialog box is only enabled when the Tubular > Pipe Inventory spreadsheet is active. After specifying an OD, one or more weights, and one or more grades, click OK to highlight all spreadsheet entries that match the selection criteria. Multiple entries can be deleted by first selecting them from the Selection dialog box located on the View menu. In the preceding example, all the 9-5/8” pipe with the following grades are selected: H-40, L-80 and Q-125. Click OK to close the dialog box. The selected pipe is highlighted on the spreadsheet. Use Edit > Delete Row to delete the selected items. Note Deleting a string currently being used in a Design removes this pipe section’s grade, weight, or both from the Tubular > String Sections spreadsheet. It must be reentered into the Tubular > Pipe Inventory for it to be used again.

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Modifying Existing Pipes If the pipe type is defined as a Standard pipe, the burst, collapse, and axial ratings are calculated by using the standard API formula. These ratings can be overwritten by defining this particular pipe as being a Special pipe type.

Click in the cell to display the pull-down list. Select Special if you want to overwrite the calculated values for burst, collapse, and axial strength.

The Standard pipe type uses API Alternate (“special”) Drift diameter by default. To specify an API Minimum Drift, select the Min. API Pipe Type. Note If the pipe is being used in a Design, the properties cannot be modified until that pipe is temporarily removed from the string sections spreadsheet.


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Inserting a New Pipe You can insert a pipe into the spreadsheet by using either the Edit or right-click menu commands. Click the row below where you want to insert a new row. Select Edit > Insert Row (or right-click and select Insert Row from the drop-down menu) to insert the row. Add the information needed to define the pipe.

Refresh the spreadsheet for the Standard ratings to be calculated after the data is entered. The pipe type can then be modified to Special, and the customized ratings can be entered.

Tubular Properties The Tubular Properties node contains items that allow you to define the physical properties of any unusual pipe grades or special materials (such as corrosion resistant alloys), as well as the deration of the material's yield strength as a function of temperature. Tubular Properties is available from the Well Explorer tree. To open a specific spreadsheet, double-click the desired Tubular Properties item, or right-click it and select Edit from the drop-down menu.

Tubular Properties spreadsheets are not included in the Wizard list.

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Locking Tubular Properties and Password Security All Tubular Properties spreadsheets contain a Locked check box. Select this check box to prevent editing of the tubular properties data. When locked, users can open the respective dialog box in read-only mode, but cannot save any changes. If this check box is selected and a Tubular Properties password has been specified, you are prompted for the password before you can deselect this check box. To change or remove password security applied to locking or unlocking Tubular Properties, right-click the Tubular Properties node in the Well Explorer and select Change Tubular Properties Password from the menu.

A security token is available in the EDM Administration utility to enable this command and allow users to initially set and then change the Tubular Properties password. The Old Password field is enabled when changing an existing password. If the old password is entered but the new password field is left blank, password security is removed and Tubular Properties are unlocked without the need for a password.

CAUTION Use caution when applying Tubular Property security because EDM Administrators need the old password to reset a forgotten password. Passwords are encrypted and require Database Administrators to use a SQL or Oracle tool to clear.


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Importing and Exporting Tubular Properties Import and Export right-click menu commands are available from the Tubular Properties node in the Well Explorer. Custom (user) defined class, material, derations, and grades are exported as a Tubular Transfer (*.tub.xml) file. Once exported, the *.tub.xml file can then be imported into a different EDM database.

Grades The Grade spreadsheet is used to define the physical properties of all pipe grades or special materials (such as corrosion-resistant alloys) used in the pipe inventory and catalog. The grades you define will be used as a selection list when defining a component using catalogs; for example, when you select a grade in the Tubular > String Sections spreadsheet. You must enter a unique name to define the grade. Specify the yield strength, the ultimate tensile strength, and the underlying material behavior (mechanical and thermal properties).

Specify grades on the Tubular Properties > Grade spreadsheet.

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Notes •

Material behavior is further defined by the selection of a Material name leading to two additional spreadsheets (Materials Properties Spreadsheet and Temperature Deration Spreadsheet).

•

Changes made to grade properties affect the current design only (localized change). If the selected grade exists in the Tubular Properties Summary table, this grade will be associated with the string section and used in calculations. Thus, all pipes with the same grade use the same properties.

•

If a grade is API, it is read only and cannot be altered or deleted.

Grade Spreadsheet Columns

Grade This cell contains the name of the specified pipe grade. No two grades should have the same name.

Material This cell contains a pull-down list of available material types. The material is defined in a separate spreadsheet (Material Properties) to capture the mechanical and thermal properties of the underlying material from which the pipe grade has been manufactured.

Minimum Yield Strength This editable cell contains the yield strength of the pipe grade. This information is echoed within the pipe inventory and is used to default the pipe ratings (burst, collapse, and axial). Additionally, triaxial stress analysis is compared to this value for determination of sufficiency in design. Note Analysis for anisotropic materials is not presently implemented in the StressCheck software. All material-strength properties are assumed to be isotropic.


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Fatigue Endurance Limit Enter the fatigue endurance limit of the pipe. This value is used in the Torque Drag analysis. Fatigue endurance limit is not a constant value that is related to the yield strength of the pipe. 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.

Ultimate Tensile Strength (UTS) This editable cell contains the ultimate tensile strength (UTS) of the pipe grade. This information is also echoed within the pipe inventory, and it is used under special conditions to default the axial ratings of API connections made of this grade.

Materials The Materials spreadsheet is used to define the physical properties of all alloys used in the pipe inventory and catalog. Materials are defined by a unique name. Each material name is then further characterized by several mechanical and thermal properties. The Steel (default) entry can be edited but not deleted. The properties in this entry represent those of low-alloy carbon steel, which is used in nearly all casing applications for oil and gas wells. Most of the time, the default option is all you will need when creating new grades and linking to the material choice. However, if you are using CRA materials, such as austenitic alloys (for example, Incoloy 825, Hastelloy G-3, or Sanicro 28), which have significantly different mechanical and thermal properties than the Steel (default), you should add additional entries to this spreadsheet characterizing their behavior. In addition to the typical mechanical and thermal properties characterizing a material’s behavior, this spreadsheet allows for the specification of a schedule used to determine how a material’s (and ultimately a grade’s) minimum yield strength is affected by temperature. Currently, the temperature deration schedule only applies to the pipe body and not to the connections employing the material choice.

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Material Properties Spreadsheet Columns

Material Name This cell contains the name of the material whose properties are being specified. No two entries should have the same material name. The Steel (default) material may have its properties edited, but the entry cannot be deleted.

Young’s Modulus This cell contains Young’s modulus for the material from which pipes of this material are made.

Poisson’s Ratio This cell contains Poisson’s ratio for the material from which pipes of this material are made.

Density This cell contains the density for the material in pounds per cubic foot. The density of steel (490 lbm/ft^3) is the default value.

Expansion Coefficient This cell contains the thermal expansion coefficient for the material from which pipes of this material are made.


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Radial Yield Factor This cell contains the radial yield factor of the material from which pipes of this material are made. For certain pipe materials—notably the corrosion-resistant alloys (CRAs)—the minimum yield strength (MYS) may be anisotropic (that is, not be the same in all directions). In this case, the MYS is based on the axial MYS, and factors are used to reduce the MYS in the radial and hoop directions.

Hoop Yield Factor This cell contains the hoop yield factor of the material from which pipes of this material are made. For certain pipe materials—notably the corrosion-resistant alloys (CRAs)—the minimum yield strength (MYS) may be anisotropic (that is, not the same in all directions). In this case, the MYS is based on the axial MYS, and factors are used to reduce the MYS in the radial and hoop directions.

Temperature Deration Schedule Name This cell contains a pull-down list of available temperature deration schedules. The schedule is defined in a separate spreadsheet (Temperature Deration) to capture the deration of the material’s yield strength as a function of temperature.

Class Click to expand the Tubular Properties node in the Well Explorer, and then double-click Class to open the Class spreadsheet. You can also right-click Class and select Edit from the drop-down menu to open the spreadsheet. This spreadsheet is used to compile a list of tubular classes and associated properties. This list is used as a selection list while defining a component using catalogs.

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Class Spreadsheet Columns

Service Class Enter a unique name to identify the class. The defined classes are used as a selection list for defining the class of some components using catalogs.

Wall Thickness (%) Enter the percentage of the total wall thickness that is associated with the specified service class. The wall thickness percentage is used to calculate the existing outside diameter of the tubular.

Description Type a short description of the class.

Temperature Derations Click to expand the Tubular Properties node in the Well Explorer, and then double-click Temperature Derations to open the Temperature Deration spreadsheet. This spreadsheet is used to define the schedule used to derate the minimum yield strength of a material as a function of the temperature. Temperature deration schedules are defined by a unique name. Each schedule name is then further characterized by a multi-linear decay of the yield strength versus temperature. The default schedule entry can be edited but not deleted. This default schedule corresponds to a linear reduction in yield strength of 0.03% per ° F. This schedule is used for the Steel (default) material that describes the low-alloy carbon steels represented by the typical API pipe grades in the inventory. Any new schedule created should have at least two temperature deration points defined, as shown in the following graphic, to capture the linear decay behavior.


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Temperature Deration Spreadsheet Columns

Temperature Deration Schedule Name This cell contains the name of the temperature deration schedule whose properties are being specified. No two entries should have the same name. You may edit the default schedule properties, but you cannot delete the entry.

Temperature Deration Points Up to ten pairs of points can be specified to characterize the deration of the material’s yield strength as a function of temperature. Each pair of points consists of a temperature and a correction factor associated with that temperature. The default schedule corresponds to a linear reduction in yield strength of 0.03% per °F. This pair is entered in the spreadsheet as the following two points: Temperature (°F)

Correction Factor

68

1.00

500

0.87

The default schedule can be modified (edited) if desired but not deleted.

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Chapter 5

Well and Formation Information The first stage of well design is to define the general well configuration and formation information, which defines the overall parameters governing the well conditions. All the subsequent casing strings will use this global definition of the well.


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Chapter 5: Well and Formation Information

Entering Well Data This section shows the process of creating a new Design and entering general well data, pore pressure/fracture gradient/geothermal gradients, pressure and fracture and geothermal gradients in the StressCheck™ software. Next, a simple casing scheme is defined, and then the data can be viewed graphically in a Well Schematic.

Creating a New Design To create a new Design, select a wellbore and right-click, then select New Design. The Design Properties dialog box opens.

Design Properties Dialog Box The Design Properties dialog box is used to create a new Design and to provide information regarding creation and modification of the Design. This dialog box contains three tabs: General and Audit info and Change History.

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General Tab (Design Properties Dialog Box) Use the General tab 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 in this dialog box is used for informational and reporting purposes and is not required. The following fields are present: In the Details section: •

Design - Type the name that will be used to identify the Design. The name must be unique. Note If the Design is locked check box is selected, you cannot edit any of the fields.

•

Version - Type the version of the Design.

•

Phase - Select the phase of the Design from the pull-down list (Prototype, Planned, or Actual). The list of phases that appears 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 pull-down list 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 pull-down list. A calendar dialog box will open. Use the arrow buttons in the calendar dialog box to move to the desired month, and then click the day. The date you select populates the field. Click arrows to change to desired month.

Click on the desired day.


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

Datum Elevation - This shows a read-only display of the elevation entered for the selected Depth Reference datum (set in the Well Properties dialog box).

•

Air Gap (MSL) or (Ground) - Air Gap is calculated from MSL and displayed. Air Gap is the distance from ground level/sea level to the rig floor. It is used in some calculations for hydrostatic head. 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 MSL). Elevation and Ground Level are set on the Depth Reference tab in the Well Properties dialog box. 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 If you change the datum and it causes a negative air gap to be calculated, a warning message appears to inform you that you cannot select this datum.

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•

[System Datum] - This is the current System Datum.

•

Mudline Depth (MSL) - (Offshore only) This is 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 box.

•

Mudline TVD - (Offshore only) This is the distance from the Depth Reference Datum to the sea bed (datum Elevation + Water Depth).



Select the Design is locked check box to prevent editing of the Design data. If this check box is selected and a Locked Data password has been specified, you will be prompted for the password before you can deselect this check box. For more information, see “Data Locking” on page 3-11.

Audit Info Tab (Design Properties Dialog Box) The Audit tab displays when the Design was created, the last modification date, and the person who changed the data. Audit tabs are available on all data node properties dialog boxes. You can track modification of data by using the Audit Info tab in the Properties dialog box for each data type. Using the Well Explorer, right-click on Company, Project, Site, Well, Wellbore, or Design, and then click the Audit Info tab. This information indicates who modified the Company, Project, Site, Well, Wellbore, Design, and so on. Also displayed is the date the item was modified and the application that was used to modify the item.

This information indicates who created the Company, Project, Site, Well, Wellbore, Design, and so on. Also displayed is the date the item was created and the application that was used to create the item.

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


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Change History Tab (Design Properties Dialog Box) The Change History tab provides historical audit information related to Wellbores, Designs, and Cases in the associated Properties dialog boxes. The Change History tab is populated by Engineer’s Desktop applications whenever additions, deletions, or modifications to design entered data are made. Specifically, changes are recorded when a user adds to, updates, deletes, runs (WELLPLAN™ and COMPASS™ software only), and copies data within EDM™.

Note Use Change History Logging systems setting in the EDM Administration Utility to enable or disable the recording of Change History. See EDM Administration Utility Help for details.

Entering General Well Information Select the Wellbore > General > Options tab to specify:

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•

A description of the well

•

Well depth (MD)

•

Vertical section definition and local reference information (when the well is deviated)


Chapter 5: Well and Formation Information Select the Comments tab to enter additional Well information such as location. Comments are optional.

Well Depth is required to access most of the remaining data entry forms. The depth should be greater than or equal to the shoe of the deepest string defined in the Wellbore > Casing and Tubing Scheme spreadsheet.

Field and Controls

Description The Description can include general remarks about the Well, such as the name, field, and lease. This description is included on the bottom of all printed documents if the Headers and Footers check box is selected in the Tools > Options dialog box.

Well Depth (MD) The Well Depth is the along-hole measured depth (MD) of the Well. This depth should be greater than or equal to the shoe of the deepest string defined in the Wellbore > Casing and Tubing Scheme spreadsheet. When the well depth is defined as a depth greater than the setting depth for the last casing (or liner) string, the assumption of drill-out in the resulting final open-hole interval is made in the formulation of load cases. This depth is required as a reference point for automatically generating data, such as the undisturbed temperature, pore pressure, fracture pressure, and wellbore deviation profiles. It is also used to determine whether drilling loads will be enabled for a selected string in the Tubular > Burst Loads and Tubular > Collapse Loads dialog boxes.


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Origin N The Origin N value describes the North distance from the wellhead to the local origin. The default value for Origin N is 0.0 (the wellhead is positioned at the local origin). Non-zero values for Origin N cause a displacement of the wellpath origin (wellhead) from the local origin (plot origin) on View > Deviation Plots > Section View and View > Deviation Plots > Plan View deviation plots. It also affects the VSection data in the Survey Editor spreadsheet; positive values for Origin N indicate North displacements from wellhead to local origin, while negative values indicate South displacements.

Origin E The Origin E value describes the East distance from the wellhead to the local origin. The default value for Origin E is 0.0 (the wellhead is positioned at the local origin). Non-zero values for Origin E cause a displacement of the wellpath origin (wellhead) from the local origin (plot origin) on View > Deviation Plots > Section View and View > Deviation Plots > Plan View deviation plots. It also affects the VSection data in the Wellbore > Wellpath Editor spreadsheet; positive values for Origin E indicate East displacements from wellhead to local origin, while negative values indicate West displacements.

Azimuth The Azimuth value describes the orientation of a vertical plane onto which the wellpath vertical section is projected. The default value for Azimuth is 0.0 (due north).

Entering Pore Pressure Data Select the Wellbore > Pore Pressure spreadsheet to define the pore pressure or gradient profile as a function of true vertical depth. This data is used to calculate external pressure profiles and to provide default values for load cases specified in the Burst Loads and Collapse Loads dialog boxes. This spreadsheet is always included in the Wizard list.

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Pressures can only be entered on a TVD basis and can be specified as either a pressure or an equivalent mud weight (EMW). The StressCheck software automatically calculates the other value.

You can specify the location of permeable zones on this form. The base of the zone is assumed to be the depth of the next data point. Permeable zone data can be used to calculate external pressure profiles.

Enter pore pressure data from top down on this spreadsheet.

The pore pressure profile can be viewed graphically by using View > Formation Plots > Pore Pressure or View > Formation Plots > Pore, Fracture & MW Plot. In the latter case, pore pressure is characterized as an effective mud weight (EMW) gradient.

Pore Pressure Spreadsheet Columns Abrupt escalations or regressions in the pore pressure profile can be established by entering two depths separated by one depth unit on successive lines, along with respective pore pressure or EMW entries.

Vertical Depth Use the Vertical Depth cell to specify a TVD (true vertical depth) corresponding to a given pore pressure. Between depth entries, the pore pressure profile is constructed by linear interpolation. The Vertical Depth cell for the first line is initialized to the depth corresponding to MGL (mean ground level) for land wells, or the depth corresponding to ML (mudline) for platform and subsea wells. It reflects the System Datum set in the Project Properties dialog box and elevation specifications set on the General tab of the Well Properties dialog box.

Pore Pressure Use the Pore Pressure cell to specify a pore pressure corresponding to a TVD in the Vertical Depth cell. When a value is changed in the Pore


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Pressure cell, the EMW cell value is automatically calculated, and vice versa.

EMW Use the EMW cell to specify an effective mud weight pore pressure gradient corresponding to a TVD in the Vertical Depth cell. When a value is changed in the EMW cell, the value in the Pore Pressure cell value is automatically calculated, and vice versa.

Permeable Zones The Permeable Zone cell is used in association with the external pressure method for burst or collapse load generation. If the wellbore is exposed to a permeable zone at the specified depth, click Yes for the setting in this cell. When selected, the permeable zone begins at the depth for the entry and continues until the next specified depth in the Wellbore > Pore Pressure spreadsheet.

Entering Fracture Gradient Data Select the Wellbore > Fracture Gradient spreadsheet to define the fracture pressure or gradient profile as a function of true vertical depth. The fracture pressure profile can be viewed graphically using View > Formation Plots > Fracture Gradient Plot or View > Formation Plots > Pore, Fracture & MW Plot. In the View > Formation Plots > Pore, Fracture & MW Plot, fracture pressure is characterized as an EMW gradient. Pressures can only be entered on a TVD basis and can be specified as either a pressure or an equivalent mud weight (EMW). The StressCheck software automatically calculates the other value.

Enter fracture gradient data from top down on this spreadsheet.

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Note The data entered on the Fracture Gradient spreadsheet are used as boundary conditions in the calculation of certain external pressure profiles and to provide default values for load cases specified in the Tubular > Burst Loads and Tubular > Collapse Loads dialog boxes.

Fracture Gradient Spreadsheet Columns Abrupt escalations or regressions in the fracture gradient profile can be established by entry of two depths separated by one depth unit on successive lines, along with respective fracture pressure or EMW entries.

Vertical Depth Use this cell to specify a TVD (True Vertical Depth) corresponding to a given fracture pressure. Between depth entries, the fracture pressure profile is constructed by linear interpolation. Abrupt escalations or regressions in the fracture pressure profile can be established by entering two depths separated by one depth unit on successive lines, along with respective fracture pressure or EMW entries. The Vertical Depth cell for the first line in this spreadsheet is initialized to the depth corresponding to MGL (mean ground level) for land wells, or the depth corresponding to ML (mudline) for platform and subsea wells. It reflects the System Datum set on the General tab of the Project Properties dialog box and elevation specifications on the Depth Reference tab of the Well Properties dialog box.

Fracture Pressure Use the Frac Pressure cell to specify a fracture pressure corresponding to a TVD in the Vertical Depth cell. When a value is entered or changed in the Fracture Pressure cell, the value in the EMW cell is automatically calculated, and vice versa.

EMW Use the EMW cell to specify an effective mud weight fracture pressure gradient corresponding to a TVD in the Vertical Depth cell. When a value is entered or changed in the EMW cell, the value in the Fracture Pressure cell is automatically calculated, and vice versa.


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Defining a Squeezing Salt/Shale Zone Select the Wellbore > Squeezing Salt/Shale spreadsheet to define squeezing salt or shale sections for collapse design. This spreadsheet is used to enter collapse loads due to formations, such as salt zones that exhibit plastic flow or creep behavior. Over the depth interval(s) for which they are specified, these loads will replace the external pressure profile specified in the Tubular > Collapse Loads dialog box. The external collapse load is normally assumed to be equal to the overburden pressure and this load is applied uniformly to the pipe OD. To define a zone, the Zone TVD and Base TVD values are required. Data is only entered for TVD values, either as a pressure or a pressure gradient/EMW.

If no specific pressures are known, then 1.0 psi/ft is used through the salt zone.

Pressures must be specified at both the top and base of a zone. The pressures at intermediate depths within a zone are determined by linear interpolation.

Squeezing Salt/Shale Spreadsheet Columns

Zone Top Use the Zone Top TVD cell to specify the TVD (true vertical depth) to the top of the salt zone. The portion of the string exposed to this high collapse load is defined by the values specified for Zone Top and Zone Base.

Zone Base Use the Base TVD cell to specify the TVD (true vertical depth) corresponding to the base of the salt zone. The portion of the string exposed to this high collapse load is defined by the values specified for Zone Top and Zone Base.

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Overburden Pressure at Top, (psi) Use the Overburden Pressure at Top (psi) cell to specify the collapse pressure to which the string will be exposed at the top of the zone. When data in this cell is entered or changed, the corresponding value in the (ppg) cell is automatically calculated, and vice versa.

Overburden Pressure at Top, (ppg) Use the Overburden Pressure at Top (ppg) cell to specify the collapse effective mud weight gradient to which the string will be exposed at the top of the zone. When data in this cell is entered or changed, the corresponding value in the (psi) cell is automatically calculated, and vice versa.

Overburden Pressure at Base, (psi) Use the Overburden Pressure at Base (psi) cell to specify the collapse pressure to which the string will be exposed at the base of the zone. When data in this cell is entered or changed, the corresponding value in the (ppg) cell is automatically calculated, and vice versa.

Overburden Pressure at Base, (ppg) Use the Overburden Pressure at Base (ppg) cell to specify the collapse pressure to which the string will be exposed at the base of the zone. When data in this cell is entered or changed, the corresponding value in the (psi) cell is automatically calculated, and vice versa.


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Managing Wellpath Data Entering Wellpath Data Select the Wellbore > Wellpath Editor spreadsheet to define a wellbore trajectory description for planar and three-dimensional directional wells. The three preferred methods (MD-INC-AZ, INC-AZ-TVD, and INC-AZ-DLS) can be used in any combination at different depths.

For all data entry types, a larger dogleg can be specified in the Max Dogleg field for build and drop sections. These Max Doglegs are utilized in bending analysis. Additional doglegs can be specified on the Wellbore > Dogleg Severity Overrides (independent of deviation) spreadsheet. Maximum Dogleg values do not affect the well trajectory.

When data values are entered, calculation of those values not entered is performed.

StressCheck versions prior to V3.1 used direct linear interpolation between depths in the wellpath trajectory definition in order to map MD and TVD at particular depths that are points-of-interest from a computational point-of-view, a methodology with inherent error (particularly for sparse well trajectory definitions). With implementation of the Wellbore > Wellpath Editor, the StressCheck software now uses minimum curvature interpolation for all point-ofinterest mapping of MD and TVD, except where the MD-TVD data input format has been used. There are three preferred methods used to specify a well profile. These methods are used in the preceding example. These can be used in any combination at different depths: • •

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Measured Depth, Inclination, and Azimuth (MD-INC-AZ) Inclination, Azimuth, and True Vertical Depth (INC-AZ-TVD)



•

Inclination, Azimuth, and Dogleg Severity (INC-AZ-DLS)

Note You must use type 1 (MD-INC-AZ) as the starting type, and not INC-AZ-TVD or INC-AZ-DLS types.

There is a fourth data entry method that cannot be mixed with the previous three: •

Measured Depth and True Vertical depth pairs. Any attempt to mix this type with the other types will produce a warning message. Note Because the MD-TVD method does not calculate dogleg severity, stress calculations are not performed.

Import Wellpath File Select File > Import > Wellpath to open the Import Wellpath File dialog box. It is used to import and load delimited text survey files created by a different program (for example, the Landmark COMPASS software) into the Wellpath Editor.


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File format must be ASCII text, and it must be formatted as specified below.

The format for survey files to be imported into the Wellbore > Wellpath Editor with this utility command are indicated below. •

The file must be tabular delimited text, and use any combination of spaces, tabs, or commas as field delimiters.

•

Column 1 is reserved for measured depth, and measured depth values must be in increasing order and positive values.

•

Column 2 is reserved for inclination.

•

Column 3 is reserved for azimuth, and azimuth values must be 0.0° < AZ < 360.0°.

Dogleg Severity Overrides Spreadsheet Select the Wellbore > Dogleg Severity Overrides spreadsheet to define intervals of wellbore curvature independent of the deviation profile defined in the Survey Editor. This spreadsheet is used to enter dogleg severity (DLS) data, as a function of measured depth interval, that will be used (if greater) to override DLS or Max DLS data in the Wellbore > Wellpath Editor spreadsheet for the purpose of bending stress calculation.

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Additional tension due to bending is superimposed onto the axial load profile based on the maximum local value of doglegs specified on this form and the Wellbore > Wellpath Editor spreadsheet.

Dogleg Severity Overrides can be used to include consideration of bending in vertical wells.

Dogleg Severity Overrides Spreadsheet Columns

Top Use the Top cell to specify the measured depth at which the interval for which the dogleg severity override will apply begins.

Base Use the Base cell to specify the measured depth at which the interval for which the dogleg severity override will apply ends.

Dogleg Severity Use the DLS cell to specify a dogleg severity override to be used over the measured depth interval defined by Top and Base. Note The DLS intervals specified in Wellbore > Dogleg Severity Overrides can overlap intervals for which DLS and Max DLS are defined in the Wellbore > Wellpath Editor spreadsheet. At any depth, the greater of the three will prevail in the determination of bending stress. Dogleg Severity Overrides will be reflected, where they prevail over other local DLS definitions (DLS or Max DLS in the Survey Editor spreadsheet), in the View > Deviation Plots > Dogleg Severity Profile plot.


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Viewing the Dogleg Overrides Graphically You can view the dogleg severity overrides using the View > Deviation Plots > Dogleg Severity Profile plot.

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Defining the Geothermal Gradient Select the Wellbore > Geothermal Gradient > Standard tab to specify basic formation temperature data.

The Mudline field displays only when the Offshore check box is selected in the Well Properties dialog box.

The default values are 80 °F at the surface, 40 °F at the mudline, and a 1.5° F/100 ft gradient to the well TD. You can add additional intermediate temperature points on the Wellbore > Geothermal Gradient > Additional tab. Use the Additional tab to specify additional formation temperature which can be used to characterize a more complex formation.

Fields and Controls

Surface Ambient The Surface Ambient temperature for an onshore well is the temperature at MGL. For an offshore well (select the Offshore check box in the Well Properties dialog box), the surface ambient temperature represents the


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air temperature above MSL. The default surface ambient temperature is 80° F.

Mudline The Mudline temperature field displays if the Offshore check box is selected in the Well Properties dialog box. The water temperature profile will be linear between the surface ambient temperature at MSL and the specified temperature at the mudline. The default mudline temperature is 40 °F. Temperature at Well TD Options

Temperature The temperature at the well TD can be explicitly specified or calculated from a gradient specification. To enter the value explicitly, select the Temperature option and enter the temperature at the TVD corresponding to the well TD. The well TD is specified on the Wellbore > General > Options tab as MD, but it is displayed on this tab as TVD for convenient reference. The Temperature and Gradient options are mutually exclusive. The Temperature field is disabled if the Gradient option is selected, and vice versa. The default temperature value at the well TD is computed using a 1.5° F/ 100 ft gradient. If the Temperature option is selected, the calculated gradient changes with variation in temperature at the surface for an onshore well or mudline for an offshore well, a change in TVD at the mudline or well TD, or a change in wellbore deviation.

Gradient The temperature at the well TD can be calculated from a gradient or specified explicitly. To calculate the value from a gradient, select the Gradient option and enter the gradient value. The temperature at the well TD is then calculated based on the gradient and the surface ambient temperature at MGL for an onshore well, or the mudline temperature at the mudline depth for an offshore well. The default gradient is 1.5° F/100 ft. If the Gradient option is selected, the calculated temperature changes with variation of temperature at the

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surface for an onshore well or mudline for an offshore well, a change in TVD at the mudline or well TD, or a change in wellbore deviation.

What Effect Does Temperature Have on the Analysis? Changing the temperature profile affects the worst-case temperature profiles calculated for each burst and collapse load case. Temperatures have the following effects in the StressCheck software: •

Influence axial load distributions for all burst and collapse loads based on an undisturbed initial temperature and a worst-case temperature profile.

•

Derate yield strength, and therefore, the pipe rating. To include temperature deration, select the Temperature Deration check box on the Tubular > Design Parameters > Analysis Options tab.

•

Influence the temperature and dependent gas density profiles in some burst load cases.


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Define the Casing and Tubing Scheme Select the Wellbore > Casing and Tubing Scheme spreadsheet to create and modify the preliminary well design. Each row specifies basic information about a single casing string. Pipes should be entered in the order in which they are run in the well (for example, The pipe Name and Type Conductor, Surface, Intermediate, and so on with pull-down lists contain industry-standard terms. respect to their Outer Diameter).

The default Hanger depths for casing and tieback strings are based on whether the well is an onshore, offshore platform, or subsea well. The hanger depths can be modified.

The Hole Size pull-down list contains common bit sizes that can be modified or added to by selecting Tools > Defaults > Bit Sizes.

The Mud at Shoe density field contains the density values of the mud in which the casing string was run and cemented.

The OD pull-down list is populated by the ODs in the current Tubular > Pipe Inventory spreadsheet.

The data entered on this spreadsheet is used to provide default values when specifying load cases in the Tubular > Burst Loads, Tubular > Collapse Loads, and Tubular > Axial Loads dialog boxes, and when graphically designing casing strings in the View > Design Plots > Burst Design, View > Design Plots > Collapse Design, View > Design Plots > Axial Design, and View > Design Plots > Triaxial Design plots.

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To enter and modify more detailed data about each string, use the commands under the Tubular menu. To view the casing scheme graphically, use View > Well Schematic. Note Production load cases can only be specified for strings whose Name has been designated as Production.

Fields and Controls

OD (Outer Diameter) This cell has a pull-down list that has all ODs found in the pipe inventory. If the required OD is not in this list, at least one pipe with this OD must be added to the Tubular > Pipe Inventory spreadsheet. Note The StressCheck software permits the entry of tapered (multiple OD) strings. However, tapered strings cannot be specified explicitly on this spreadsheet. To design a tapered string, use the Tubular > String Sections spreadsheet to add additional detail to the string design following the entry of the OD of the smallest tapered string on the Wellbore > Casing and Tubing Scheme spreadsheet.

Name The Name cell is used for reference and to determine applicable load cases. For this reason, it must be selected from the choices on the pull-down list for the cell. The available choices are Conductor, Surface, Intermediate, Drilling, Protective, and Production. For a particular string, you must select Production to enable most production loads on the Tubular > Burst Loads and Tubular > Collapse Loads dialog boxes.

Type Use the Type cell to open a list containing casing, liner, and tieback string types. The Type selection dictates default values used on this spreadsheet and when selecting load cases in the Tubular > Burst Loads and Tubular > Collapse Loads dialog boxes.


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When the Casing or Tieback types are specified, the Hanger cell is immediately assigned a default value. This feature is provided to help ensure data consistency, but the hanger depth default can be subsequently modified; the default hanger depth is intended to closely approximate the depth of the wellhead. For onshore wells, the default depth is the depth corresponding to MGL (that is, the elevation value specified in the Project Properties dialog box). The default depth is zero for platform wells and the mudline depth for subsea wells. For strings of type Liner, the hanger depth cell remains undefined until a value is entered. Note If the Type cell contents are modified after data is entered in the Hanger cell, the contents of the Hanger cell may automatically change to maintain data consistency. For example, if a casing or tieback is changed to a liner, the Hanger cell is automatically cleared, and requires the entry of a hanger depth. Similarly, if a liner is changed to a casing or tieback, the previously entered hanger depth is also changed to the default wellhead depth.

Hole Size Use the Hole Size cell to specify an open hole size greater than the diameter specified in the OD cell. The Hole Size cell contains a pull-down list having common bit sizes, which are specified in the Tools > Defaults > Bit Sizes dialog box. The list of available hole sizes can be supplemented with entries in the Bit Sizes dialog box. This cell is disabled if Tieback is specified in the Type cell for the string, because tiebacks are not run in open hole.

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Hanger Use the Hanger cell to specify the depth corresponding to the top of the string. When the Casing or Tieback types are specified, the Hanger cell is immediately assigned a default value. This feature is provided to help ensure data consistency, but the hanger depth default may be subsequently modified. For casing and tiebacks, the default hanger depth is intended to closely approximate the depth of the wellhead. For onshore wells, the default hanger depth is the depth corresponding to MGL (that is, the elevation value specified in the Project Properties dialog box). The default depth is zero for platform wells and the mudline depth for subsea wells. For strings of type Liner, the Hanger cell remains undefined until a value is entered. Note The contents of the Hanger cell may automatically change to maintain data consistency if the content of the Type cell is altered. For additional information, refer to the discussion on the Type cell.

Shoe Use the Shoe cell to specify the depth corresponding to the base of the casing string. For a tieback, a shoe depth must be specified that corresponds to the hanger depth for a liner.

TOC (Top of Cement) Use the TOC cell to specify the top of cement (TOC) that will affect the external pressure profile, the axial load profile for service loads, and the triaxial analysis. For a fully cemented string, set the TOC value equal to the depth specified in the Hanger cell. For a partially cemented string, set the TOC value greater (deeper) than the hanger depth. Note For an uncemented string, set the TOC value equal to the string shoe depth. Do not specify a value less than hanger depth for any string.


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Mud at Shoe Use the Mud at Shoe cell to specify the density of the mud in which the casing string was run and cemented. This density is used to calculate a hydrostatic external pressure profile outside the casing above TOC. It is also used in certain burst and collapse load cases as the mud density used during drilling below the prior string. Deteriorated mud densities can be specified on the Tubular > Burst Loads > Options and Tubular > Collapse Loads > Options tabs.

Note The mud at the shoe is the mud in which the casing string was run. If a different density fluid is used to displace the cement during the cement job, enter this fluid on the Tubular >Initial Conditions > Cementing and Landing tab.

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Well Schematic Select View > Well Schematic to display a graphical representation that characterizes the casing strings and other information specified on the Wellbore > Casing and Tubing Scheme spreadsheet. This schematic can also be displayed in any tab by selecting it from the View menu. The Well Schematic can be plotted as a function of either MD or TVD.

For this example, select the 9 5/8” production casing. You can select it by selecting it from the pull-down list or by highlighting it on the schematic.

To display cement, rightclick the schematic, and select Properties. In the Well Schematic Properties dialog box, select the Cement check box, and click OK.

The current casing string is highlighted in red. The name, OD, and shoe depth are shown at the shoe of each string. Most commands found under the Tubular menu apply only to the current string.


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To select a casing string for Design or analysis, click the string section. Alternatively, use the Wizard toolbar pull-down list of casing strings, or select Tubular > Current String.

Defining Production Data Select the Wellbore > Production Data dialog box to specify the packer depth and packer fluid density as well as the perforation depth and properties of the produced fluid. This information is used when defining the internal pressure profiles for production load cases in the Tubular > Burst Loads and Tubular > Collapse Loads dialog boxes.

Fields and Controls

Fluid Density Use the Fluid Density field to specify the density of the packer fluid. To facilitate what-if investigations and the construction of worst-case collapse load scenarios, the packer fluid density specified here can be independently overridden for the production collapse load case by selecting the Above/Below Packer check box on the Tubular > Collapse Loads > Edit tab. The default value is 8.60 ppg (seawater density).

Packer Depth Use the Packer Depth field to enter the measured depth the packer will be set in a production casing or liner. The default value is the well depth specified on the Wellbore > General > Options tab.

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Perforation Depth, MD Use the Perforation Depth field to enter the measured depth of the perforations. The default value is the well depth specified on the Wellbore > General > Options tab.

Gas Gravity Select Gas Gravity to use it as the means for gas density characterization. When Gas Gravity is used, a temperature-dependent and pressure-dependent compressibility factor is determined based on a simple gas composition for the specified gravity. This compressibility factor is used to calculate a gas density profile and surface pressure if the Tubing Leak load case is selected in the Tubular > Burst Loads dialog box. The default value of 0.70 is used for gas gravity.

Gas/Oil Gradient When Gas/Oil Gradient is selected as the means for gas density characterization, the specified gradient is used to calculate the surface pressure when the Tubing Leak load case is selected on the Tubular > Burst Loads > Edit tab. The default value of 0.1 psi/ft is used for the gas/oil gradient.

Setting Up Tabs Tabs allow you to view text and graphical data in multiple window layers. These results may be organized in logical groups. Select the Tools > Tabs dialog box to set up Tabs.


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Tabs can be created, deleted, renamed, and ordered from the Tabs dialog box on the View menu. The Lock Tab check box disables the Delete and Rename buttons and places a small Lock icon on the tab. After a tab is locked, the contents of the view cannot be changed. Any user can unlock a locked tab.

Splitting Windows into Panes Each tab can be split into panes. You can change the size of the pane as needed. Plots and spreadsheets can be opened in the panes. Panes are used in the StressCheck software to place input and output data for quick reference and printing.

Use this bar to split the window horizontally.

Use this bar to split the window vertically.

The maximum number of panes set horizontally or vertically is two.

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Splitting the Tab into Vertical Panes •

Double-click the split button located on the far left of the horizontal scroll bar.

•

Alternatively, you can drag the vertical splitter bar into position using the mouse.

By default, the well schematic always appears in a new pane.

Splitting the Tab into Horizontal Panes •

Double-click the split button located on the top right of the vertical scroll bar.

•

Alternatively, you can drag the horizontal splitter bar into position by using the mouse.

Changing the Contents of the Pane To change the contents of the pane, select the pane by clicking inside it. Then, select the spreadsheet, table, or plot you want to display from the menu bar.


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Chapter 6

Tubular Load Data Now you have entered all the general and formation information. The Wizard has grown to the maximum size, allowing you to continue to enter the specific tubular and loading information for the casing you wish to design.


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Chapter 6: Tubular Load Data

Entering Design Parameters Use Tubular > Design Parameters > Design Factor to specify tubular design factors and analysis options. This data is used in the definition of load cases and in the control of design and analysis logic.

Enter the Pipe Design Factors as specified here.

Connection design factors are optional and default to the default pipe body values if left blank.

Select these options for this section of the training.

Min Internal Drift diameter defaults based on the next hole OD defined in Wellbore > Casing and Tubing Scheme. No pipe with a Min Internal Drift diameter smaller than the value shown here will be

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Design parameters are defined for the Current String, and can therefore be specified independently for each string defined in the Casing Scheme spreadsheet. To change the currently selected string, use Tubular > Current String or the Select String pull-down list on the Wizard toolbar.


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Specifying the Initial Conditions Select the Tubular > Initial Conditions dialog box to define initial conditions for the current string to be used with load cases selected in the Tubular > Burst Loads, Tubular > Collapse Loads, and Tubular > Axial Loads (service loads only) dialog boxes. You can define: •

Cementing and landing conditions, such as fluid densities, applied surface pressure, whether the float failed, and pickup and slackoff forces

•

Initial-condition temperature profiles (default or user-defined)

This data is used to define load cases, determine the initial state of the casing, and dictate design and analysis logic. Initial conditions data is defined on a per-string basis; that is, different initial conditions data can be defined for each string in the Casing Scheme spreadsheet. To change strings, use the Tubular > Current String dialog box or the Select String pull-down list on the Wizard toolbar. The Cementing and Landing and Temperature tabs are used to specify these conditions.

Defining Cementing and Landing Data Cementing and landing data are entered on the Tubular > Initial Conditions > Cement and Landing tab to establish, for the current string, the post-cementing hydrostatic profile for certain burst (for example, Green Cement Pressure Test), collapse (for example, Cementing), and axial (for example, Post-Cement Static) load cases. Also use it to establish hydrostatic and applied loads for cemented and landed casing as an initial condition to subsequent loads and displacements that may develop from load cases selected on the

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Tubular > Burst Loads > Select, Tubular > Collapse Loads > Select, and Tubular > Axial Loads > Select tabs. Initial conditions are entered on a per string basis.

The default Mix-water Density is based on fresh water.

The default slurry densities are based on Class G neat cement.

The default Displacement Fluid Density and Float Collar Depth values are based on data entered on the Wellbore > Casing and Tubing Scheme spreadsheet.

This data is defined on a per-string basis. Different Cementing and Landing data can be defined for each string in the Wellbore > Casing and Tubing Scheme spreadsheet. To change strings, use the Tubular > Current String dialog box or the Select String pull-down list on the Wizard toolbar. The Tubular > Initial Conditions > Cement and Landing tab is always accessible from the Wizard List by using the Tubular > Initial Conditions dialog box.

Fields

Mix-Water Density Enter the density of the mix-water used to prepare lead and (if selected) tail cement slurries for single-stage primary cementation of the current string. This fluid density is used in the formulation of certain burst- and collapse-load external profiles over cemented intervals (for example,


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Mud and Cement Mix-Water, and Permeable Zones). The default value for Mix-Water Density is 8.33 ppg.

Lead Slurry Density Enter the density of the lead cement slurry used for single-stage primary cementation of the current string. This fluid density is used in the formulation for determining the initial axial load distribution of the current string after cement placement, but before applying pickup or slackoff landing loads. The length of the cemented interval is established separately by the specification of Top of Cement (TOC) for the current string in the Wellbore > Casing and Tubing Scheme spreadsheet. The default value for lead slurry density is 15.8 ppg (neat API Class G cement).

Tail Slurry Density Select the Tail Slurry Density check box if both lead and tail slurries are used for single-stage primary cementation of the current string, and enter the tail slurry density. The Tail Slurry Length must also be specified. The length of the lead slurry is established separately by the specification of TOC for the current string in the Wellbore > Casing and Tubing Scheme spreadsheet. These values, along with the lead slurry density, are used in the formulation for determining the initial axial load distribution of the current string after cement placement, but before application of pick-up or slack-off landing loads. The Tail Slurry Length field is disabled if this check box is not selected.

Tail Slurry Length Use the Tail Slurry Length field to enter the final placement length of the tail slurry column if both lead and tail slurries are used for singlestage primary cementation of the current string. This value is used in the formulation for determining the initial axial load distribution of the current string after cement placement, but before application of pick-up or slack-off landing loads. The Tail Slurry Length field is disabled if the Tail Slurry Density check box is not selected.

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Displacement Fluid Density Enter the Displacement Fluid Density used for single-stage primary cementation of the current string. Normally, the fluid used to displace the cement slurry during such a cement job is the drilling mud in which the current string was run. The default value for this field is, therefore, taken from the current-string entry for Mud at Shoe in the Wellbore > Casing and Tubing Scheme spreadsheet. An alternative value can be specified when required. Low-density displacement fluids, such as seawater, can have a significant effect on the initial axial load distribution (due to the piston force on the float collar) as well as the collapse load imparted to the current string.

Float Collar Depth Enter the MD of the float collar. The default value is the current-string shoe depth taken from the Wellbore > Casing and Tubing Scheme spreadsheet.

Applied Surface Pressure Select the Applied Surface Pressure check box and enter the required pressure if surface pressure will be applied to the current string after bumping the upper plug and held for the duration of the wait-on-cement (WOC) period. If it is not selected, the corresponding data field is disabled. The application of surface pressure during the WOC period is used to pretension the string when a pickup force cannot be applied before landing the string in the wellhead. This typically occurs in applications where a mandrel-type casing hanger is used (for example, a subsea well or a production casing string in a high-pressure well). The desired pretensioning is only achieved where wellbore-casing friction forces do not prevent the required axial displacement. For wellbore inclinations where casing will not slide of its own weight (generally, greater than 65 to 70 degrees), the ability to develop the desired axial displacement requires validation. To avoid data compatibility problems, the Float Failed check box is deselected when the Applied Surface Pressure check box is selected, and vice versa.


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Float Failed If the Float Failed check box is selected, the differential pressure normally developed across the float collar (due to the hydrostatic disequilibrium between fluids inside and outside the casing) will instead be held as a casing back-pressure at the surface in order to prevent U-tubing of cement back inside the casing from the annulus. This option should normally be selected only for sensitivity analysis after an otherwise satisfactory design for the current casing string has been obtained. To avoid data compatibility problems, the Applied Surface Pressure check box is disabled if the Float Failed check box is selected, and vice versa.

Pickup Force Select the Pickup Force option to enter a pickup force. Pickup force is the incremental upward force (above static string weight) applied to the casing string at the surface before landing the string in a slip-type casing hanger within the wellhead. Applied after the cement has hardened, the pickup force results in increased tension above the TOC depth, as specified for the current string in the Casing Scheme spreadsheet. The axial load profile below the TOC remains unchanged by a pickup force specification. The force is only considered in axial design when the Service Loads check box is selected on the Tubular > Axial Loads > Select tab. This force is typically applied to prevent thermal or hydrostatic induced buckling while drilling below the current string, or during subsequent production operations. If the Buckling check box is selected on the Tubular > Design Parameters > Analysis Options tab, buckling results are available in the View > Tabular Results > Triaxial Results

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table, including the required pickup load to eliminate buckling for the selected individual load case.

If buckling is a concern, the indicated pickup load requirement should be evaluated by selecting the Pickup Force option to verify design integrity under the increased axial loading. To specify a pickup force, select the Pickup Force option and enter the required upward force. Note Pickup force, as defined in this dialog box, is only considered in axial design when the Service Loads check box is selected on the Tubular > Axial Loads > Select tab. The pickup force is independent of the Applied Force defined in the PreCement Static Load in the Tubular > Axial Loads > Select tab.

Slackoff Force Select the Slackoff Force option to enter a slackoff force. Slackoff force is a reduction to the current-string axial load profile, immediately after cementing, by lowering of the casing before landing in the wellhead assembly. This force results in reduced tension both above and below the TOC depth, as specified for the current string in the Wellbore > Casing and Tubing Scheme spreadsheet.


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Slackoff force is only considered in axial design when the Service Loads check box is selected on the Tubular > Axial Loads > Select tab. This force is typically applied to land a tieback string in a liner-top polished bore receptacle (PBR). The additional compression at the PBR can serve several purposes, including: • •

energizing a metal seal. providing sufficient compression to prevent seal movement in the PBR during production or stimulation operations. Note The StressCheck™ software does not model the movement of uncemented tiebacks in PBRs. Nevertheless, if the Buckling check box is selected in the Tubular > Design Parameters dialog box, the effect of slackoff force on buckling above the TOC only can be evaluated for a particular load case using the View > Tabular Results > Triaxial Results table. To specify a slackoff force, select the Slackoff Force option and enter the required reduction in axial force.

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Defining the Starting Temperature Profile Select the Tubular > Initial Conditions > Temperature tab to specify the starting temperature profile for the current string. This data is defined on a per-string basis; therefore, different initial-condition temperature data can be defined for each string in the Wellbore > Casing and Tubing Scheme spreadsheet.

Select the Default temperature to use the temperature profile specified using Wellbore > Geothermal Gradient. Select User-entered to define an alternate temperature profile.

The following two temperature profiles are available. •

Select Default to use the temperature profile entered in the Wellbore > Geothermal Gradient dialog box.

•

Select User-entered to define an alternate temperature profile to establish the cemented-and-landed initial condition that serves as the baseline for assessing the effects on axial load profiles of thermal strains. These strains may arise from temperature-profile changes from the initial condition to that associated by default or user entry with a particular burst or collapse load cases, or the axial service-loads case.

This data is defined on a per-string basis; therefore, different initial-condition temperature data can be defined for each string in the Wellbore > Casing and Tubing Scheme spreadsheet. To change


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strings, use Tubular > Current String or the Select String pull-down list on the Wizard toolbar. Unlike temperature data in the Wellbore > Geothermal Gradient dialog box, user-entered temperature data on the Temperature tab are referenced to either MD or TVD. Note If you are copying temperature data from another source, be sure to verify whether the data is based on MD or TVD. Before you copy the data into this tab, be sure you have selected the correct option for MD or TVD.

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Specify Tool Passage Requirements Select the Tubular > Tool Passage dialog box to determine the maximum tool length for a specified tool OD, such that the tool (when considered as a rigid body) can freely pass through the casing (based on drift diameter) at the depth of greatest casing curvature. Alternatively, tools of a specified OD and length can be entered to determine whether they will pass through the casing under load conditions described in the design load cases. The severity of bending and buckling can have an effect on the ability of future tubulars to be freely run in the existing casing or liner. Enter the maximum length of the tool.

Enter the OD of the tool.


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The View > Tabular Results > Tool Passage Summary table displays the tool passage data entered in the Tool Passage dialog box. The results reported in this tabular summary are dynamic when Tool Passage Summary is the current view and then the Tool Passage dialog box is opened and data are entered or edited.

In this example, a 3.5” OD tool that is 100 ft long cannot pass in the well at 10,400 ft. The maximum tool length that can pass through this section is 63.40 ft.

The minimum force required for the tool to pass is 19.37 lbf.

Tubular > Tool Passage dialog box.

Results are displayed as they are entered if the View > Tabular Results > Tool Passage Summary window is open before using the Tubular > Tool Passage dialog box.

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Defining Burst Loads The Tubular > Burst Loads dialog box has several tabs to define burst loads that will serve as the basis for the current string’s burst design. The design load line is determined from the aggregate worst-case burst loading as a function of depth, with design factors and temperature deration of minimum yield strength considered for all selected burst loads. Load case data specified in this dialog box are for the current string only. Load cases must be selected and specified independently for each string entered in the Wellbore > Casing and Tubing Scheme spreadsheet. To change strings, use the Tubular > Current String command or the Select String pull-down list on the Wizard toolbar. The Burst Loads dialog box always appears in the Wizard list. The Tubular > Burst Loads dialog box has several tabs for defining these data and viewing pressure profile results.


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Selecting the Design Burst Loads and the External Pressure Profile Use the Tubular > Burst Loads > Select tab to select the burst loads you want to use in the design. Production loads can be selected only if the casing name is production.

Drilling loads can be selected if the casing shoe is shallower than the well TD.

This method will be used for all the burst load cases if a Single External Pressure Profile is selected on the Tubular > Design Parameters > Analysis Options tab.

All the burst loads are discussed in detail in the online help system.

Defining the External Pressure Profile For burst design, there are five methods of calculating external pressure profiles. For information about external pressure profiles, refer to “External Pressure Profiles” on page 2-50.

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Defining Burst Load Details Use the Tubular > Burst Loads > Edit tab to specify or view parameters for each load case and external pressure profile enabled on the Tubular > Burst Loads > Select or Tubular > Burst Loads > Custom tabs. These parameters are used to construct a specific load case or external pressure profile. The parameters available vary depending on the current load case selected. Using the data of this dialog box, the StressCheck software creates an internal pressure profile consisting of the maximum pressure seen by the casing while circulating a gas kick to the surface.

Select desired burst load or pressure profile from the drop-down list.

BHA dimensions are used to calculate bubble height as the kick is circulated out of the well.

The gas gravity and equivalent pressure gradient in psi at the depth of the influx is based on the Redlich-Kwong equation of state.

Using the Multiple tab Use the Tubular > Burst Loads > Multiple tab to apply liner(s) internal pressure test load(s) and external overlapped pressure profile(s) as internal pressure profile to other associated liner(s), casing and tieback strings set above the current string in the casing scheme.


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Pressure test load cases from any liner can be shared. Tubing or tieback pressure test load cases cannot be shared.

The Multiple tab displays a list of other strings (liners) having pressure test loads that may apply to the current string. After a pressure test load is associated to the current string other tabs, such as Edit, Temperature, Plot and Option, will support the new pressure test load. From the Multiple Tab, you can view details of a pressure test load internal pressure profile and overlapped pressure profile intervals, and can select an external pressure profile. The pressure tests are named based on the source string name and type. Each pressure test load is named by the string OD, function of the string, and the load type (pressure test).

Constraints Note how overlapping strings and user-defined temperature data are handled for multiple loads: •

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Overlap: Intermediate liner(s) overlapped pressure profile intervals will be ignored if the corresponding liner strings do not include a pressure test load.



•

Temperature: Multiple loads pressure test applied to the string of interest do not inherit user-entered temperature profile from the source liner string.

Viewing the Associated External Pressure Profile The data used in the remaining load cases or pressure profiles can be accessed by selecting the pull-down list from the Tubular > Burst Loads > Edit tab.

Select the desired load case or pressure profile from the pull-down list.

For every selected burst load case, an appropriate external pressure profile must be selected so the StressCheck software will correctly


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calculate the differential pressure. In this example, the Mud & Cement Mix Water profile is used. When the Single External Pressure Profile check box is selected on the Tubular > Design Parameters > Analysis Options tab, the selected external pressure will be used for all burst load cases

View the defining parameters for the external pressure profile from this dialog box. All load cases will use this external pressure profile because the Single External Pressure Profile check box was selected on the Tubular > Design Parameters > Analysis Options tab.

Specify Burst Load Temperature Select the Tubular > Burst Loads > Temperature tab to specify the temperature profile you want to use for the load case selected in the pulldown list at the top of this tab. You can only select load cases enabled in the Tubular > Burst Loads > Select or Tubular > Burst Loads > Custom tabs. Select the Default option to use the temperature profile as defined by the StressCheck software for that particular load case. Select the User-entered option to define an alternate temperature profile. Select the Geothermal option to use the temperature profile defined on

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the Geothermal Gradient dialog box. You can only edit temperature data if you select the User-entered option.

Select the Default option to use the temperature profile as defined by the StressCheck software for that particular load case. Select the Userentered option to enter your own temperature data. This can be in the form of output from the WELLCAT program or text file, either typed in or pasted in from a text or spreadsheet. Select the Geothermal option to use the temperature profile defined on the Wellbore > Geothermal Gradient dialog box.

Unlike temperature data in the Wellbore > Geothermal Gradient dialog box, the user-entered temperature data on this tab can be referenced to MD or TVD. Note If you are copying temperature data from another source, be sure to verify whether the data is based on MD or TVD. Before you copy the data into this tab, be sure you have selected the correct option for MD or TVD.


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View Burst Load Pressure Plots Burst load pressure plots can be graphically viewed by selecting several burst plots available from the View > Burst Plots submenu.

The View > Burst Plots > Pressure Profiles and View > Burst Plots > Differential Pressures plots characterize the internal and external pressure profiles as a function of either MD or TVD for all selected burst and custom burst load cases.

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Burst Design Load Line Burst load data can be graphically viewed by selecting several burst plots available from the View > Burst Plots menu.

The corrections conventionally applied to the nominal pipe ratings when performing a manual calculation will be applied to the Actual Load Line to create the Design Load Line. The Burst Design Load Line is corrected for temperature if the Temperature Deration check box is selected on the Tubular > Design Parameters > Analysis Options tab.


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Specifying Collapse Loads Selecting Collapse Loads Use the Select tab to enable and disable applicable collapse load cases, and to select external pressure profiles.

Select the Tubular > Collapse Loads > Edit tab to change the default parameters for each load case selected.

String name.

Drilling loads can be selected if the casing shoe is shallower than the well TD.

Production loads can be selected if the casing name is production. Five methods of calculating external pressure profiles are included for collapse design.

When the Single External Pressure Profile check box is selected on the Tubular > Design Parameters > Analysis Options tab, the selected external pressure is used for all collapse load cases.

Most drilling collapse-load cases can only be selected for strings in which the setting depth (shoe depth in Wellbore > Casing and Tubing Scheme spreadsheet) is less than the well TD, as defined in the Wellbore > General dialog box. All the collapse loads are discussed in detail in the online help system. Most production collapse load cases can only be selected for production strings (those strings in the Wellbore > Casing and Tubing Scheme

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spreadsheet for which the Name cell contents are Production). Exceptions to this rule are: •

Cementing drilling collapse load case can be selected for all strings.

•

Gas migration production collapse load case is unavailable for liners. Note The Cementing drilling collapse load case and the Gas Migration production collapse load case have self-described external pressure profiles, and are unaffected by the Single External Pressure Profile option and external pressure profile selections. The external pressure profile for collapse Custom load cases is entirely user-defined, and is similarly unaffected.

The Internal Profiles list box contains the names of the selected load cases. As load cases are enabled and disabled, this list box updates automatically, and the currently selected load case is highlighted.

Selecting Different External Pressure Profiles for Each Load Case If the Single External Pressure Profile check box is not selected on the Tubular > Design Parameters > Analysis Options tab, external pressure profiles can be independently selected for each load case. Highlight a load case in the Internal Profile list box, and select the corresponding external pressure profile from the External Profile box. If the Single External Pressure Profile check box is selected, only one external pressure profile can be selected for use with all of the selected load cases.

Defining Collapse Load Details Select the Tubular > Collapse Loads > Edit tab to specify or view parameters for each load case and external pressure profile enabled on the Tubular > Collapse Loads > Select and Tubular > Collapse Loads > Custom tabs. The tab parameters are used in constructing a specific load case or external pressure profile. The parameters available


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vary depending on the current selection. Some parameter values are editable, while others are listed for information purposes only.

Edit the default parameters for the Fluid Gradients w/ Pore Pressure load case. Set the Fluid Gradient Above and Below TOC to the same mud weight to model a poor cement job with a continuous column of mud behind the casing.

Viewing Collapse Load Pressure Plots Collapse load data can be graphically viewed by selecting several collapse plots available from the View > Collapse Plots menu.

In this case, the Lost Returns w/ Mud Drop load case represents the design basis for collapse. In the case of production loads, analysis of the Above/ Below Packer load case is beneficial to determine the highest collapse pressure.

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Collapse Design Load Line The View > Collapse Plots > Load Line plot characterizes the actual and design load lines as a function of either MD or TVD for all selected collapse and custom collapse load cases.

The collapse load line is corrected for temperature, tension, and internal pressure. The correction for tension constantly updates the load line when different weights of casing are selected.

The design load line on this plot is the same as (and always consistent with) the design load line on the collapse View > Design Plots > Collapse plot. This plot is used for interactive graphical design and visual comparison of current-string API collapse rating with design collapse loads. The design load line for collapse represents the maximum design collapse pressure as a function of depth based on consideration of all


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selected collapse and custom collapse load cases for the current string, and after the following adjustments: •

Correcting the applied collapse pressure to an effective collapse pressure based on the effect of internal pressure on collapse resistance

•

Applying to each load case the appropriate collapse design factor from the Tubular > Design Parameters dialog box (the default) or from a load-case specific alternate design factor specification on the Tubular > Collapse Loads > Options tab

•

Adjusting the design load line to compensate for the effect of elevated temperature on minimum yield strength (and, hence, collapse rating) when the Temperature Deration check box is selected on the Tubular > Design Parameters > Analysis Options tab for the current string

•

Considering the effect of tensile axial loading on collapse resistance

The actual load line for collapse represents the maximum actual differential pressure (effective collapse pressure due to effect of internal pressure on collapse resistance) as a function of depth based on the load case or cases that dominate in construction of the design load line.

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Specifying Axial Loads Details Select the Tubular > Axial Loads > Select tab to enable or disable axial loads against which the current string is evaluated. To enable the load case, select the corresponding check boxes. After they are enabled, the load case variables, such as overpull force or casing running speed, can be edited.

Select axial load cases on the Select tab.

Running and cementing loads that can be considered include: •

Running loads that consider shock loads due to instantaneous deceleration from a running speed

•

A required incremental overpull force when running casing

•

A pressure test performed when bumping the plug while the cement is in its fluid state, creating a large piston force

In addition, you can include in the axial design all the axial load profiles resulting from the burst and collapse load cases by selecting the Service Loads check box on the Tubular > Axial Load > Select tab. All of the axial loads are discussed in detail in the online help.


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Defining Custom Loads In addition to the selection of load cases that automatically create internal and external pressure, the StressCheck software allows you to customize a load scenario and apply it as a burst or collapse criterion in the design process together with the automated loads.

Displaying the List of Existing Custom Loads Use Tubular > Custom Loads dialog box to access the list of defined custom loads contained in the current library, define new custom loads, and display and manage your custom loads spreadsheets.

List of existing custom load cases.

Click the buttons on the right side of the dialog box to create, delete, or rename custom load cases.

Important! This dialog box has no Cancel button, so any changes made through this dialog box cannot be undone. Pressing Esc instead of clicking Close writes all your changes to the catalog, but the currently selected custom load is not activated.

The Custom Loads dialog box manages a library of custom loads spreadsheets that are saved with the current Design. Each spreadsheet contains a custom load profile consisting of external pressures and internal pressures at given depths. Temperature data for custom loads are recorded as a user-entered temperature profile for the selected custom load on the tab in the Tubular > Bust Loads > Temperature or Tubular > Collapse Loads > Temperature tabs, as appropriate to the nature of the custom

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load. The default temperature profile is geothermal on the Temperature tab when a custom load is selected as the current load.

Renaming a Custom Load Click Rename in the Tubular > Custom Loads dialog box to change the name of the currently selected custom load. Rename the custom load RTTS.

Click Close to close the dialog box and begin editing load data.

Editing Custom Load Data Define the Pressure Profile Select the Tubular > Custom Loads spreadsheet to define custom load internal and external pressure profiles as a function of measured depth. Create a custom load when none of the internal and external pressure profiles automatically generated (for example, the Gas Migration


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internal profile and the Mud and Cement Mix-Water external profile) satisfy design requirements.

Custom load profiles can be selected as burst, collapse, and axial service loads from the Tubular > Burst Loads > Custom and Tubular > Collapse Loads > Custom tabs, respectively. Custom loads are only considered as axial service loads when the Service Loads check box is selected on the Tubular > Axial Loads > Select tab. They are also taken into account in triaxial and minimum cost design.

Loads are defined on a per string basis; therefore, different loads can be defined for each string in the Wellbore > Casing and Tubing Scheme spreadsheet. To change strings, use the Tubular > Current String command or the Select String pull-down list on the Wizard toolbar. Specify and edit numerous custom loads by using the Select Custom Load pull-down list and custom load buttons on the Template toolbar. Depth values on this spreadsheet are always expressed as MD. When data are entered for a deviated well, and hydrostatic pressures are calculated for use in a custom load case, recall that the pressures must be calculated for the TVD corresponding to the MD of interest for the

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line entry. The relationship between MD and TVD for the current well can be reviewed by using the Deviation Profile table. Even though depths are entered on a MD-basis, the pressure data are interpolated and extrapolated on a TVD-basis (a reasonable convention, because almost all pressure loads applied to casing strings are hydrostatic in nature). If an extrapolated pressure value is less than zero, it is assigned the value zero.

Including the Custom Load in the Analysis Select the Tubular > Burst Loads > Custom tab to specify the custom load pressure profile(s) you want to use as a burst load case for the active string.

Select the box to include this pressure profile as a burst load case.

Defining the Custom Load Temperature Profile Use the Tubular > Burst Loads > Temperature tab to specify the temperature profile you want to use for the load case selected in the pulldown list at the top of this tab. You can only select load cases enabled on the Select and Custom tab in the Burst Loads dialog box. Select the Default option to use the temperature profile as explained in Burst Load Case Methodologies. Select the User-entered option to define an alternate temperature profile. Select the Geothermal option to use the


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temperature profile defined in the Geothermal Gradient dialog box. You can only edit temperature data if you select User-entered.

Select the desired custom load case.

Select the temperature profile you want to use.

The temperature profile for a particular load case can also be viewed as a plot using Burst Plots > Temperature Profiles. Unlike temperature data in the Wellbore > Geothermal Gradient dialog box, the temperature data on this tab can be referenced to MD or TVD.

Shut-in Load Cases Select the Shut-in check box as the load case on the Tubular > Burst Loads > Select tab. Proceed to the Edit tab and select Shut-In from the list. Select the Hot check box, if you want the bottom hole temperature to be continuously applied to the surface. Deselect the Hot check box if

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the surface temperature needs to be continuously applied to the base of the tubing.

Note If you are copying temperature data from another source, be sure to verify whether the data is based on MD or TVD. Before you copy the data into this tab, be sure you have selected the correct option for MD or TVD.

Viewing the Pressure Profiles Including the Custom Load You can view the burst load plots including the custom load just as you did for the predefined burst loads.

Plots include the custom load (RTTS) profile.


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Chapter 7

Graphical Design You can use the StressCheck™ software in three ways during your casing design process. This section of the course discusses each of these options in the following order. •

Use the StressCheck software to perform an automated design using either a full API casing list or a user-defined inventory.

•

Use the StressCheck software to verify an existing string weight and grade.

•

Use the minimum cost tool for an automated optimization for uniaxial, biaxial, and triaxial casing design.


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Chapter 7: Graphical Design

Performing an Automated Design Checking Burst Design Using the Burst Design Plot Select the View > Design Plots > Burst plot to perform graphical burst-load casing design, or to check the burst design of a string specified on the Tubular > String Sections spreadsheet. Depth is on the vertical axis and burst pressure (effective burst load) is on the horizontal axis. Initially, the design load line is constructed from the maximum burst loads based on selected load cases.

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The Pipe Rating curve is not displayed on the plot because a pipe section has not yet been created.



Creating a Pipe Section A string section that meets all pipe-body burst design criteria has a pipe rating line that is at all points (over the string section length) to the right of the design load line.

Click the pipe section. (Notice the cursor has changed.)

Read pipe description here.

1. To specify a casing string to begin your Design, double-click anywhere on the design view. A rating line corresponding to the highest rated pipe in the inventory for the current OD is displayed. 2. To quickly view a description of the pipe that the StressCheck software selected, click the rating line. The pipe description is displayed on the left corner of the status bar. Since a pipe section has been created, two lines are shown. One line is


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the burst design load line, and the other line is the burst pipe rating line. Note The Burst Design plot does not reflect the implications for burst design integrity of connection selections for string sections in the current string. After a pipe-body design is performed, the effect of connection selections on design integrity can be assessed directly in the Tubular > Connections spreadsheet.

What is the Burst Design Load Line? The burst design load line reflects the maximum burst differential pressure experienced by the casing as a function of depth. It is based on the load cases selected on the Tubular > Burst Loads > Select tab. This pressure was multiplied by the burst design factor specified for the current string on the Tubular > Design Parameters > Design Factors tab, or the burst load case-specific alternate design factors specified on the Tubular > Burst Loads > Options tab. When different (that is, alternate) burst design factors are used for different selected burst load cases, the design factor reflected in the design load line may vary with depth as a function of the burst load case having local control over burst design.

Effects of Temperature Deration When the Temperature Deration check box is selected for the current string on the Tubular > Design Parameters > Analysis Options tab, the local minimum yield strength (MYS) of the casing in each string section and the local burst rating are derated as a function of local temperature. This effect is considered in the burst design plot by increasing the local design load line values by the local ratio of original to temperature-derated MYS, and not by decreasing the burst rating line. The default (worst-case) or user-entered temperature profiles specified on the Tubular > Burst Loads > Temperature tab are used to determine MYS temperature deration for each load case selected on the Tubular > Burst Loads > Select and Tubular > Burst Loads > Custom tabs.

What is the Pipe Rating Line? The constant burst ratings displayed in this curve correspond to the burst rating values specified in the Tubular > Pipe Inventory spreadsheet for the one or more pipes listed in the current string’s Tubular > String Sections spreadsheet. Showing the effect of MYS temperature deration on the design load line allows the burst rating lines to remain constant

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(vertical), and they can be more easily manipulated with a mouse. A string section that meets all pipe-body burst design criteria has a pipe rating line that is at all points (over the string section length) to the right of the design load line. Note The pipe rating line does not appear until you have created a pipe section. Double-click anywhere on the design plot to create a pipe section.


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Modifying a Pipe Section The current string’s weight and grade can be changed by manipulating (dragging) the pipe rating line. Each vertical section of the pipe rating line represents a different string section. String sections can be created, deleted, or modified by clicking, pointing, and dragging the rating line. Changes made to the current-string design by manipulating the line(s) are reflected on the View > Design Plots > Collapse, View > Design Plots > Axial, and View > Design Plots > Triaxial design plots as well as in the current string’s Tubular > String Sections and Tubular > Connections spreadsheets, and vice versa.

Click the pipe you want to change, and drag to the left, towards the load line.

1. To modify the casing design to economically meet the design criteria, place the mouse pointer over the rating line. The pointer changes shape and becomes two vertical bars with arrows pointing left and right.

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2. Click and drag the rating line toward the load line. 3. Release the button when the rating line begins to intersect the load line (that is, the safety factor equals the design factor at the intersection point). 4. The StressCheck software adjusts the location of the rating line to correspond with the pipe in the current inventory that has the closest greater burst rating. The basic premise of graphical design is that pipe with a lower rating is probably more economical. Designs with a rating line close to the load line are usually more economical.

The pipe selection was changed and the burst criteria is still met.


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Comparing Burst and Collapse Design Checks A side-by-side comparison of Burst and Collapse loads provides a way to quickly determine if the pipe rating line adjustment satisfies collapse criteria for the selected string.

The collapse criteria are not met in the lower portion of the string.

Checking Collapse Design Using the Collapse Design Plot Use View > Design Plots > Collapse plot to perform graphical collapse-load casing design or to check the collapse design of a string specified on the Tubular > String Sections spreadsheet. Depth is on the vertical axis, and collapse pressure (effective collapse load) is on the horizontal axis. Two lines are shown: the collapse design load line and the collapse pipe rating line. When the design load line remains to the left of the pipe rating line, the design for collapse is taken to be acceptable based on the current string’s collapse design criteria.

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What is the Collapse Design Load Line? The design load line for collapse represents the maximum design collapse pressure as a function of depth based on consideration of all selected collapse and custom collapse load cases for the current string. The design load line also includes: •

Correcting the applied collapse pressure to an effective collapse pressure based on the effect of internal pressure on collapse resistance.

•

Applying the appropriate collapse design factor to each load case, either from the Tubular > Design Parameters > Design Factors tab (the default) or from a load case–specific alternate design factor specification on the Tubular > Collapse Loads > Options tab

•

Adjusting the design load line to compensate for the effect of elevated temperature on minimum yield strength (and, hence, collapse rating) when the Temperature Deration check box is selected on the current string’s Tubular > Design Parameters > Analysis Options tab.

•

Considering the effect of tensile axial loading on collapse resistance.

What is the Pipe Rating Line? The constant collapse ratings shown in this plot correspond to the collapse rating values specified in the Tubular > Pipe Inventory spreadsheet for the one or more pipes listed in the current string’s Tubular > String Sections spreadsheet. Showing the effect of axial tension loads and MYS temperature deration on the design load line allows the collapse rating lines to remain constant (that is, vertical), and more easily manipulated with a mouse. A string section that meets all pipe-body collapse design criteria has a pipe rating line that is at all points (over the string section length) to the right of the design load line.


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To summarize, the effects on collapse resistance of both tension and MYS temperature deration are considered in this plot by calculating a reduced collapse rating for each string section, as a function of depth and local tension and temperature. API Bulletin 5C3 collapse formulation is used with derated yield strength due to tension and temperature (when the Temperature Deration check box is selected on the Tubular > Design Parameters > Analysis Options tab for the current string). The load line (API Bulletin 5C3 effective collapse pressure) is adjusted to reflect the appropriate design factor (possibly as a function of depth, when using alternate design factors), and then multiplied by the ratio of the nominal API collapse rating to the reduced collapse rating as a function of depth. Reduction in collapse rating for tension and MYS temperature deration is shown by increasing the load line and not by decreasing the rating line. The current string’s weight and grade can be changed by manipulating (dragging) the pipe rating line. Each vertical section of the pipe rating line represents a different string section. String sections can be created, deleted, or modified by clicking, pointing, and dragging the rating line. Changes made to the current-string design by manipulating the pipe rating line(s) are reflected on the View > Design Plots > Collapse, View > Design Plots > Axial, and View > Design Plots > Triaxial design plots as well as in the current string’s Tubular > String Sections and Tubular > Connections spreadsheets, and vice versa.

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Adding a Section to Satisfy Design Criteria A new section can be added graphically from the Collapse Design plot.

Notice the new section. Sections are marked with an X at each end.

1. To create an additional pipe section that will meet design criteria, position the mouse pointer near the depth you want to create a new section (but not directly on the pipe rating line). 2. Double-click to create a new section at the pointer depth. An “X” marker denotes the section change.


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3. Move the rating line until you satisfy the design criteria as described on “Modifying a Pipe Section” on page 7-6.

Notice the two pipe sections. The change is applied to the burst design plot also.

Checking Axial and Service Load Profiles The following example shows a comparison of the Axial Load Profiles and the Service Load Profiles, with consideration for bending. The axial load profile displays an overall view of the axial load profile as a function of either MD or TVD, while the Service Load Profiles plots characterize the axial load with bending-induced pseudo-loads for all burst and collapse load cases (including custom load cases) selected for the current string.

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The View > Axial Plots > Load Profiles > Apparent w/Bending plot shows the axial load profile for each axial load case selected for the current string. The aggregate Service Loads Profile is included if the Service Loads check box is selected on the Tubular > Axial Loads > Select tab.

The View > Axial Plots > Service Load Profiles > Apparent w/Bending plot illustrates how this Service Loads Profile is constructed. It is formed from the absolute maximum values of axial load produced by the pressure effects of the burst and collapse load cases selected for the current string.

Using the Axial Load Profiles Plot The View > Axial Plots > Load Profiles plot characterizes the axial load profile as plots that display the following axial load profile plots as a function of either MD or TVD, depending on the final selection from the View > Axial Plots > Load Profiles submenu: •

Apparent (with bending-induced pseudo-loads included)

•

Actual (without bending-induced pseudo-loads)

•

All apparent and actual axial load cases are displayed for the current string, including the aggregate service load profile (if Service Loads is a selected axial load case), burst load cases, and collapse load cases


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The aggregate service load profile is shown when service loads is a selected axial load case for the current string. The aggregate service load profile includes the effect of: •

Thermal strain due to temperature change

•

Ballooning due to differences between internal and external pressure profiles

•

Piston forces at end areas and cross-section changes

•

Pick-up and slack-off loads specified on the Tubular > Initial Conditions > Cementing and Landing tab

•

Buckling (if the Buckling check box is selected on the Tubular > Design Parameters > Analysis Options tab)

•

Top of cement (TOC)

Each effect may apply to the individual burst or collapse case specific service load profiles and yield the maximum service load line when adjusted with design factors for temperature deration and taken in the aggregate.

Using the Axial Service Load Profiles Plots The View > Axial Plots > Service Load Profiles plots characterize the axial load with bending-induced pseudo-loads and without bending-induced pseudo-loads for all burst and collapse load cases (including custom load cases) selected for the current string. The actual load profile displayed depends on the final selection from the View > Axial Plots > Service Load Profiles submenu. The apparent and actual axial load cases include the effects of:

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•

Thermal strain due to temperature change

•

Ballooning due to differences between internal and external pressure profiles

•

Piston forces at end areas and cross-section changes

•

Pick-up and slack-off loads specified on the Tubular > Initial Conditions > Cementing and Landing tab



•

Buckling (if the Buckling check box is selected on the Tubular > Design Parameters > Analysis Options tab)

•

Top of cement (TOC)

Each effect may apply to the individual burst or collapse service load case. This plot explicitly traces the concatenation of service load profile segments used to construct this composite profile plot.

Using the Service Load Lines Plot This plot displays when the Service Loads check box is selected as an axial load case for the current string on the Tubular > Axial Loads > Select tab. It represents all service load profiles from the View > Axial Plots > Service Load Profiles plot after adjustment with the respective design factors and the effect of elevated temperature on minimum yield strength (temperature deration). Plot data is derived from either the Tubular > Design Parameters > Design Factors tab, or from the alternate design factors specified for each respective load case on the Tubular > Burst Loads > Options or Tubular > Collapse Loads > Options tabs. This plot is provided to facilitate user insight into the process by which this Service Loads profile plot is determined. This concatenation of service load profile segments, as a function of depth, corresponds to the service load line segments that define the composite maximum load line that can be traced in the View > Axial Plots > Service Load Profiles plot.


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Checking Axial and Triaxial Design The following example shows a comparison of the Axial and Triaxial design plots. The Axial plot allows you to perform graphical axial-load casing design or to check the axial design of a string. The Triaxial plot allows you to perform graphical casing design based on triaxial stress analysis or to check the triaxial design of a string.

Burst and collapse considerations control most Designs. If an adjustment is necessary based on axial or triaxial design, it can be made from the Axial Design plot.

For this string selection, both axial and triaxial design meet the criteria.

Using the Axial Design Plot Select the View > Design Plots > Axial plot to perform graphical axial-load casing design or to check the axial design of a string specified on the Tubular > String Sections spreadsheet. Depth is on the vertical axis and axial force (effective axial load) is on the horizontal axis. The axial design load line and the axial pipe rating line are displayed on this plot. When the design load line remains to the left of the pipe rating line, the design for tension and compression is taken to be acceptable based on the current string’s axial design criteria.

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What is the Axial Design Load Line? The axial design load line reflects the maximum apparent axial load experienced by the casing as a function of depth, based on the load cases selected in the Tubular > Axial Loads dialog box. The line is adjusted by adding an axial pseudo-load to reflect bending-induced increases in axial stress. When different (alternate) axial design factors are used for different selected axial-load and axial service-load cases, the design factor reflected in the design load line may vary with depth as a function of the axial load case or service-load case having local control over axial design.

Effects of Temperature Deration When the Temperature Deration check box is selected for the current string on the Tubular > Design Parameters > Analysis Options tab, the local minimum yield strength (MYS) of the casing in each string section (and hence, the local axial rating) is derated as a function of local temperature. This effect is considered in the axial design plot by increasing the local design load line values by the local ratio of original to temperature-derated MYS, and not by decreasing the axial rating line. Default temperature profiles for the axial running and installation are used to determine MYS deration for each load case selected on the Tubular > Axial Loads > Select tab. Default or user-entered temperature profiles for service loads are determined using the Tubular > Burst Loads > Select, Tubular > Burst Loads > Custom, Tubular > Collapse Loads > Select, or Tubular > Collapse Loads > Custom tabs. For service loads, the temperature profile for each selected burst or collapse load (including custom loads) can be specified and reviewed on the Tubular > Burst Loads > Temperature or Tubular > Collapse Loads > Temperature tab, and can be viewed on the burst and collapse temperature profile plots. In the StressCheck software, the local tension loading for service loads is based on the actual axial load distribution for all selected burst and collapse service load cases (including custom loads). It includes the effect of temperature change, ballooning due to burst pressure or reverse ballooning due to collapse pressure, piston forces due to end areas, area changes, plugs, wellbore deviation, and pickup or slackoff loads specified on the Tubular > Initial Conditions > Cementing and Landing tab. TOC depth is specified in the Wellbore > Casing and Tubing Scheme spreadsheet.


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What is the Axial Pipe Rating Line? The constant axial ratings shown in this plot correspond to the axial rating values specified in the Tubular > Pipe Inventory spreadsheet for one or more pipes listed in the current string’s Tubular > String Sections spreadsheet. Showing the effect of MYS temperature deration on the design load line allows the axial rating lines to remain constant (vertical), and they can be more easily manipulated with a mouse. A string section that meets all pipe-body axial design criteria has a pipe rating line that is at all points (over the string section length) to the right of the design load line. Reduction in axial rating for MYS temperature deration is shown by increasing the load line and not by decreasing the rating line. The current string’s weight and grade can be changed by manipulating (dragging) the pipe rating line. Each vertical section of the pipe rating line represents a different string section. String sections can be created, deleted, or modified by clicking, pointing, and dragging the rating line. Changes made to the current-string design by manipulating the pipe rating line(s) are reflected on the burst, collapse, and triaxial design plots as well as in the current string’s Tubular > String Sections and Tubular > Connections spreadsheets, and vice versa. Note The Axial Design plot does not reflect the implications for axial design integrity of connection selections for string-sections in the current string. After a pipe-body design is performed, the effect of connection selections on design integrity can be assessed directly in the Tubular > Connections spreadsheet.

Using the Triaxial Design Plot Select the View > Design Plots > Triaxial command to perform graphical casing design based on triaxial stress analysis or to check the triaxial design of a string specified on the String Sections spreadsheet. Depth is on the vertical axis and von Mises’ equivalent (VME) stress is on the horizontal axis.

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Because the design load line is to the left of the pipe rating line, the design for triaxial loading is acceptable.

Two lines are shown: the triaxial design load line and the triaxial pipe rating line (that is, the minimum yield strength for each string section). When the design load line remains to the left of the pipe rating line, the design for triaxial loading is taken to be acceptable based on the triaxialdesign-criteria for the current string.


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The triaxial design load line reflects the maximum state of combined loading experienced by the casing as a function of depth, based on the current-string load cases selected in the Burst Loads, Collapse Loads, and Axial Loads dialog boxes. All effects considered in the formulation of their respective unfactored load lines—temperature deration, as with the burst, collapse, and axial design plots—is considered as an adjustment to the factored triaxial load line. The triaxial design factor is specified in the Design Parameters dialog box. When different (that is, alternate) triaxial design factors are specified for selected burst, collapse, axial, and axial service-load cases in the Options tab of the Load Case dialog box, the design factor reflected in the triaxial design load line may vary with depth as a function of the load case having local control over triaxial design. Triaxial analysis does not specifically address design considerations such as buckling and collapse, both of which must be addressed separately. When the Buckling check box is selected in the Design Parameters dialog box for the current string, buckling data is included in the results available in the Triaxial Results. The available data includes the overall buckled length (inclusive of both sinusoidal and helical buckling modes), the overpull required to eliminate buckling, and the buckling-induced bending stress (included with the bending stress inferred on the basis of local wellbore curvature). Except for thick-walled pipe, API collapse behavior is an elastic or inelastic instability problem rather than one of precollapse yield. Triaxial analysis should not be used in tracing the collapse integrity of casing strings. The constant ratings shown in this plot correspond to the minimum yield strength values specified in the Pipe Inventory spreadsheet for the one or more pipes listed in the String Sections spreadsheet for the current string. Showing the effect of MYS temperature deration on the design load line allows the triaxial rating lines to remain constant (that is, vertical), and they can be more easily manipulated with a mouse. A string section that meets all pipe-body triaxial design criteria has a pipe rating line that is at all points (over the string section length) to the right of the design load line. Again, reduction in effective yield strength for MYS temperature deration is shown by increasing the load line, and not by decreasing the rating line.

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In this plot, and in contrast to the convention employed in the burst, collapse, and axial design plots, the current string’s weight and grade can be changed by manipulating (dragging) both the design load and pipe rating lines, respectively. Manipulating the design load line pages through available inventory as a function of weight (for constant grade), while manipulation of the pipe rating line pages through available inventory as a function of grade (for constant weight). Each vertical section of the pipe rating line represents a different string section. String sections can be created, deleted, or modified by clicking, pointing, and dragging the rating line. Changes made to the current-string’s design by manipulating the load line and/or the pipe rating line(s) are reflected on the Burst, Collapse, and Axial design plots as well as in the current-string’s String Sections and Connections spreadsheets, and vice versa. Note This plot does not reflect the implications for design integrity of connection selections for string section in the current string. After a pipe-body design is performed, the effect of connection selections on design integrity can be assessed directly in the Connections spreadsheet.


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Using the Triaxial Design Limit Plot The View > Triaxial Check > Design Limits plot is a representation of the VME stress with API ratings. The plot shows one string section at a time. In this example, the plot displays data for the active string section.

All load cases for the upper string are within the uniaxial design criteria and also the triaxial design envelope. Note Temperature deration is not considered in the Triaxial Design Limit plot.

To view data for another string section, select the string from the Wizard.

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Modify a Design The Tubular > String Sections spreadsheet allows you to manually modify an existing design or enter a design you would like to check using the StressCheck software. A cost summary is displayed on this spreadsheet.

This string has two sections.

Cost summary.

The current depths, ODs, weights, and grades can be changed from this spreadsheet. Any changes made here are reflected in the design plots and vice versa.


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Checking a Specific Casing Design You can also analyze a specific string rather than allowing the StressCheck software to suggest a string. First, you must delete any strings that may already exist. Then, you must enter the string you want to analyze. Because the string is defined as a 9 5/8” Protective Casing, you must first define the string size as 9 5/8”.

1. Access the Tubular > String Sections spreadsheet. 2. Delete any existing rows. 3. Enter the weight, grade, and depth of string section. Double-click on a cell to access the available pipe sections. Enter one line for each pipe section. To create a Tapered String, enter another section, and then enter the depth at which the second section starts. Specify the weight and grade of the new string.

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Compressional Load Check Select the Tubular > Compression Load Check dialog box to compute the compressive loads at the wellhead for the conductor and surface casing.

This calculation is only a check. It is not used by the StressCheck software to calculate minimum cost designs. The compressive forces and absolute safety factors are displayed as results. Conductor and surface string section data must be entered. If the conductor and surface string data is not present, the following dialog box appears:


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You can view the results by selecting View > Tabular Results > Compression Load Check. Note The compression load check results reflect values for a vertical well even if the well being analyzed is a deviated well. Therefore, the results are always the maximum values.

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Minimum Cost Design Use the Tubular > Minimum Cost > Parameters tab to specify basic minimum-cost solution constraints.

The Cost of K-55 Steel is used in conjunction with cost factors in the Tubular > Pipe Inventory to rank the cost of steel during the automated design. Modifying this value updates all the plain end costs of pipe in the current inventory.

Fields and Controls Maximum Number of Sections In the Maximum Number of Sections field, enter the maximum number of string sections that have different weight and grade that can be tolerated in the minimum-cost casing design.

Minimum Section Length In the Minimum Section Length field, enter the minimum tolerable length to be considered for a particular string section in the minimum-cost casing design solution.

Cost of K-55 Steel In the Cost of K-55 Steel field, specify the baseline reference cost, per unit mass, for API grade K-55 plain-end casing. This value, in


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combination with the grade-specific default factors entered in the Tools > Default > Cost Factors dialog box, is used to cost all casing in the minimum-cost casing design solution. Note The StressCheck defaults for the cost of K-55 steel and the related grade-specific cost factors are based on information available at the time of release and may not accurately reflect grade-related differences in the cost of plain-end casing. The costs for oil-country tubular goods (OCTGs) are determined, in general, within the context of a commodity- and inventory-driven marketplace. The baseline cost for plain-end K-55 casing, as well as the default cost factors found in the Tools > Defaults > Cost Factor dialog box, should be validated against your understanding of prevailing casing costs within your organization.

Select the Tubular > Minimum Cost > Design tab to select regions of the API design envelope and triaxial design ellipse within which minimum-cost design solutions must reside. Click an area to include it or remove it from the analysis. All gray areas will be included in the minimum cost design. In this example, the minimum cost design will be governed by these criteria and not take advantage of the increased burst capability with increased tension or fall into undesirable triaxial areas, such as the bottom left quadrant.

The API design envelope is bounded by the burst limit state at the top; the compression and tension limit states to left and right, respectively; and the collapse limit state at the bottom. The triaxial design ellipse is bounded by the projected Von Mises failure surface for the minimum yield limit state.

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Gray-shaded areas within either the API design envelope or the triaxial design ellipse indicate portions of either or both design regions that you selected as legitimate domains for evolution of minimum cost designs. The gray zone (design domain) can be made larger or smaller by clicking various parts of the plot. Click a gray area changes the area to white, which excludes that area from the design domain. Note The design domain is of a generalized form; that is, no burst, collapse, axial, or triaxial design factors are explicitly stated. Design factors used in association with minimum-cost design within the selected design domain are specified in the Design Parameters dialog box, or on the Options tab for each selected load case in the Burst Loads, Collapse Loads, or Axial Loads dialog boxes.

Minimum Cost Search Select View > Design Plots > Minimum Cost to open the Minimum Cost Search dialog box. This dialog box automatically finds a minimum-cost design solution for the current string using available inventory, grade-dependent costs per unit mass, all boundary conditions, load-case constructs, design criteria and constraints, and minimum-cost search parameters specified by the user.

Status of the cost search is displayed.

You can monitor the progress of the minimum-cost search, and cancel or end the search at any time.


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Select API and Premium Connections Select the Tubular > Connections spreadsheet to select regular 8 round (STC or LTC) or buttress (BTC) couplings if they are available for the current OD and weight. If a premium connection has been specified on the Tubular > Special Connections Inventory spreadsheet for the current OD, weight, and grade, it can also be selected from the pulldown list. The asterisk (*) indicates the connection does not meet design criteria.

Select connection from pull-down list.

When a connection is selected, the corresponding safety factors are displayed so you may evaluate its suitability. A default price of the pipe and connection that determines the total cost of a section is shown. The default price can be changed to reflect the actual cost to your purchasing department. Select the Tubular > Connections spreadsheet to specify, view, and evaluate connections for each string section in the current string. These connections are based on preliminary design information specified on the Wellbore > Casing and Tubing Scheme spreadsheet.

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The Tubular > String Sections spreadsheet is first used to fully define the geometry, unit weight, and strength characteristics for the current string. The Tubular > Connections spreadsheet is the companion that is subsequently used to specify corresponding API or proprietary (premium) connection type, associated properties, and to assess the suitability of the selections face-to-face connection design criteria for burst and axial loads. Connection selection and evaluation should only be performed after a satisfactory pipe body design is established. For this reason, entries in the Tubular > Connections spreadsheet cannot be made until at least one string section for the current string is defined in the Tubular > String Sections spreadsheet. After a connection is specified for a string section, connection safety factors based on the current design criteria display so that the connection performance can be immediately evaluated. On the Tubular > Connections spreadsheet, a default value for unit-length cost of the current string section, with connections, is displayed in the Pipe + Conn cell. This value can be modified to match actual costs. Based on the values for Pipe + Conn, the cost for each string section is displayed in the Cost column. The total cost of the current string is displayed directly under the column heading in the Cost column header.


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Define Premium Connections Premium connections need to be defined in the Tubular > Special Connections spreadsheet and then selected for that particular string section in the Tubular > Connections spreadsheet. Select the desired connection from the pull-down list.

The line defining the premium connection cannot be edited after the connection is selected for use. Note Minimum Cost or Triaxial Design does not take into account any connections. The suitability of API and premium connections must be confirmed and checked separately here.

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Chapter 8

Analyzing Tabular Results and Reports In the previous chapter, you learned which design plots are available in the StressCheck™ software and how results are displayed graphically. The StressCheck software also displays results in tables and reports, which are discussed in this section of the course.


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Chapter 8: Analyzing Tabular Results and Reports

Input Data Tables The View > Input Data Tables submenu contains commands for displaying tables summarizing the data found on all dialog boxes on the Wellbore and Tubular menus, and permits the export to other documents, as OLE objects, of dialog box-specific user-entered data.

Input Data Tables submenu

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Tabular Results The View > Tabular Results submenu items summarize, in tabular form, the data found on all dialog boxes on the Wellbore and Tubular menus. When you select an item from this submenu, the contents of the active window pane are replaced by a table that presents the information described by the submenu item title.

Tabular Results submenu


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The View > Tabular Results submenu items summarize, in tabular form, the data found on all dialog boxes on the Wellbore and Tubular menus. You can export the data entered in a dialog box as an OLE object and include it in a custom report. When you select an item from this submenu, the contents of the active window pane are replaced by a table that presents the information described by the submenu item title. View > Tabular Results > String Summary summarizes the string sections and burst, collapse, axial, and triaxial design safety factors.

Viewing the String Summary The View > Tubular Results > String Summary table displays a summary of the configuration, design factors, and cost summary for the string currently selected and constituent string sections.

This summary is a subset of the View > Tabular Results > Well Summary table. It includes the name of the current string plus the OD, weight, grade, connection type, depth interval, drift diameter, minimum burst, and collapse, axial, and triaxial safety factors. It also includes the cost for each string section, and the total cost for the string. When “N/A” displays in place of numerical entries in the burst, collapse, axial, or triaxial safety factor summaries, it indicates that no applicable loads were selected. For example, if no axial loads were selected on the Tubular > Axial Loads > Select tab, the cells in the column for axial safety factors display “N/A”. Safety factors greater than 100 are not reported. Instead, “+100” is displayed. Safety factors can be displayed as either absolute (rating divided by applied load) or normalized (absolute divided by the appropriate design factor). Safety factor conventions can be toggled by using the Normalized/ Absolute Safety Factors icon on the Engineering toolbar, or by

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specifying either one as a preferred safety factor by using the Tools > Options dialog box.

An asterisk displayed before a safety factor indicates that the safety factor does not meet a user-defined design factor criterion for a load of that type (for example, burst). If connections are considered in the design, a letter code may appear after a safety factor, which indicates that the design is connection-limited at that depth. Connection ratings for API casing couplings are calculated by using the formulations in API Bulletin 5C3. Ratings for proprietary premium connections are specified on the Tubular > Special Connections spreadsheet. Many premium connections commonly used are included in the Special Connections library, and can be exported directly to the Tubular > Special Connections spreadsheet.

What is the Maximum Allowable Wear? The View > Tabular Results > Max Allowable Wear table displays the maximum allowable wear for which the absolute burst and collapse safety factors will remain greater than or equal to the appropriate design factors as a function of depth. Allowable wear is presented both as a percentage of nominal wall thickness and as a wear depth. Additionally, the remaining wall thickness is presented. The OD, weight, and grade of


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each section defined on the Tubular > String Sections spreadsheet is also listed at the depth for the section top.

Depth can be displayed as either MD or TVD by toggling the MD/TVD conversion icon on the Engineering toolbar, or by specifying either one as a preferred depth by using the Tools > Options dialog box.

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The alpha-numeric symbols following the burst and collapse values indicate the case used to calculate the values for Remaining Wall Thickness at each depth. Note Maximum allowable wear for collapse is based on a determination of the minimum wall thickness that, when using the standard API Bulletin 5C3 collapse formulations, preserves the minimum allowable collapse safety factor. No consideration is given to the particular geometry of the wear and the possible resulting influence on collapse resistance. Wear is treated as if it were uniformly distributed around the casing inner circumference. So-called “high-collapse” casing grades are evaluated by the same methods used for standard API grades of the same minimum yield strength. High-collapse performance, where it can be substantiated, is normally a result of exceptional geometric properties (such as very low eccentricity, ovality, and wall-thickness variation), and improved collapse resistance is therefore assumed to be compromised as a consequence of wear.


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Reporting in the StressCheck ™ Software and Microsoft Word There are two main ways of creating a casing design report, including: •

Creating and printing a report within the StressCheck software.

•

Copying and pasting StressCheck input tables and results into a Microsoft Word report

Generating StressCheck™ Software Reports Select the Tools > Reports > Titles tab to add, remove, and define custom reports. Custom reports can contain as much or as little data as you want displayed. They can consist of one or several spreadsheets, tables, plots, or schematics. These reports can be displayed using the Print Preview command and printed using the Print command. Reports are customized using the three tabs shown below.

A list of available reports is displayed.

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Click New to create a new report.


Select the Tools > Reports > Contents tab to add content to the report.

Click Add to add items to the report.

The Add Contents dialog box opens. Here, you can select the content to include in the report.

You can select more than one item at a time by holding Ctrl-Shift down while clicking the desired items.

Click OK when you have finished your selections.

After all content is selected in the Add Contents dialog box, configure the report as needed by reordering and/or removing items.


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Selected items display in the Contents tab.

Configure the report with the Up, Down, or Remove buttons.

Select the Tools > Reports > Options tab to set options for pagination, display of string data, and the page orientation.

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Previewing and Printing StressCheck™ Software Reports Use File > Print Preview to preview an item before printing it. The selected item is viewed from this utility exactly as it will be printed. You may view multiple pages simultaneously, move from one page to the next, and zoom in and out. Click Print to print the selected item.

Select the number of pages of the report that you want to view.

Select the report you want to view from the pull-down list.


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Multiple pages of the report can be viewed, and you can click any of the pages to zoom in and view a single page. Select 6 Pages to view all six pages of the report at one time.

To print the currently selected item, click Print on the toolbar (you may also click Close and then select File > Print).

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Chapter 9

Exercises The following exercises are designed to reinforce and challenge your knowledge of the StressCheck™ software while you participate in this course, and to act as refresher training in the future. If there is data mismatch, your instructor will assist you by either troubleshooting or providing you with the clean data set. During the course, your instructor will guide you through the exercises and assist with any questions that may arise.


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Chapter 9: Exercises

StressCheck™ Software Exercise Overview The exercises in this book are designed to familiarize you with the StressCheck software. All of the exercises analyze a single Well.

Exercise 1: Reviewing/Creating the Data Hierarchy In this exercise you will review the data hierarchy created during the CasingSeat exercise: Company, Project, Site, Well, Wellbore, and Design. If the data hierarchy has not been created yet, please follow Exercise 1 in the CasingSeat training manual.

Exercise 2: Preferences and Workspace Configuration In this exercise, you will set defaults and configure tabs.

Exercise 3: Reviewing/Specifying General Data This exercise builds on the previous two exercises. Using the data hierarchy created in Exercise 1, you will specify additional data that defines the Design you are analyzing. The purpose of this exercise is to provide you with the opportunity to understand the styles of data input and the content of the Wellbore menu.

Exercise 4: The Design Process This exercise helps you understand design load selection and the design process.

Exercise 5: Minimum Cost In this exercise, you will use the minimum cost feature to determine if there is a more economical string selection.

Exercise 6: Analyzing Results This exercise familiarizes you with the management and presentation of results on the desktop.

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Exercise 7: Tables and Reports This exercise familiarizes you with the available results types and printed reporting. Most of the answers to the questions in the exercise will be found under the View > Tabular Results menu.

Exercise 8: Sensitivity Analysis In this analysis, you will perform a design check using: • • •

special pipe tubular properties tapered design high collapse casing with extreme collapse loading conditions

Exercise 9: Independent Exercise This independent exercise designs a liner string.

Exercise 10: Template Exercise This exercise shows basic steps to build a template.


9-3


Exercise 1: Reviewing/Creating the Data Hierarchy 1. Launch the StressCheck software (select Start > Programs > Landmark Engineer’s Desktop 5000.1 > StressCheck). 2. Enter edm as the User ID and Landmark1 as the Password on the login screen.

3. Import the file SC_Class.edm.xml. 4. From the Well Explorer, double-click (or right-click and select Open from the right-click menu) to open Design E3S0P1. Select the Normal (System) template.

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Exercise 2: Preferences and Workspace Configuration 1. Create a new unit system called “Oilfield API” based on the API unit system. Change the Oilfield API mud weight units to psi/ft. Select the API unit system tab. What API unit is used for Force? Select the API unit system as the Active Viewing Unit System. 2. Before proceeding, ensure the desktop preferences are set to show the Detailed Wizard List, and display Depths as MD and Safety Factors as Absolute values. 3. Create ten new tabs, and rename the existing default tab. Name the tabs: Work, Schem, Path, Pore and Frac, Design, String and Connection, Min ASF, Burst, Collapse, Axial, and Triaxial. 4. Assign views to the following tabs as follows: • Work: Leave as is. • Path: Wellbore > Wellpath Editor. • Pore and Frac: Split the pane vertically, then assign as follows: — Left pane: Wellbore > Pore Pressure — Right pane: Wellbore > Fracture Gradient You will configure the other tabs later in the exercises. 5. Add additional bit sizes, if they do not already exist: 7”, 8.25”, 14.75”, 33”, and 42”.


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6. Save and close the E3SOP1 Design. Note Throughout the remainder of the exercises, if a Change History dialog box appears, click Save. Optional: to deactivate the display of the Change History Updates dialog box: 1

Right-click the Database node ( ) in the Well Explorer.

2

Select Change History > Configure from the drop-down menu.

3

Select the Do not display change history update window check box.

Select this check box to disable the display of the Change History dialog box. 4

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Alternatively, to turn off the Change History Updates dialog box, activate the Do not show this message again check box in the lower left corner of the dialog box. If you want to activate the Change History Updates dialog box later, perform steps 1 through 3 above, but deselect the Do not display change history update window check box.



Exercise 2 Answers 1. To create a new unit system called “Oilfield API” that is based on the API unit system: a) Select Tools > Unit System to open the Unit Systems Editor dialog box. b) Click New to open the New Unit System dialog box. Enter Oilfield API as the name of the new unit system. Select API from the Template pick-list to use the API unit set as the basis for the new unit system, and then click OK to return to the Unit Systems Editor dialog box.

Enter Oilfield API as the Name of the new unit system.

Click New to open the New Unit System dialog box.


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c) Select Mud Weight from the Class list. Select psi/ft from the Select Unit list. Do not click OK at this stage.

Select psi/ft (psi per foot) from the Select Unit list.

Select Mud Weight from the Class column.

d) Select the API unit system tab. The Class unit Force displayed that corresponds to the API unit system is lbf, while the Active Viewing System is “Oilfield API”.

Select Force from the Class column.

9-8

Notice that lbf is the unit assigned to Force.



e) Select API from the Active Viewing Unit System pick-list, and then click OK. Select API from the Active Viewing Unit System pick-list, and then click OK.


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2. Make the required selections in the Tools > Options dialog box.

Select to display depths as MD.

Select the Detailed Wizard List check box.

Select to display the Absolute Safety Factors.

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3. Select Tools > Tabs. Create new tabs, and then rename them as specified.

Click New to create tabs, and then click Rename to specify the name of each tab.

Click and drag this control to view all the tabs (or use the arrows at the left to scroll tabs into view).

When complete, tabs should appear at the bottom of the main window as specified.

4. Select the tabs listed below, and then assign views. a) The Work tab is a working tab, and the contents will change during the execution of the steps in each exercise. Note By default, the Well Schematic displays in all new tab panes.

b) Select the Path tab, and then select Wellbore > Wellpath Editor.


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c) Select the Pore and Frac tab, and then split the tab in vertical panes.

Double-click the vertical splitter bar located on the left of the tab scroll controls. Alternatively, drag the vertical splitter bar into position using the mouse.

Click the title bar of each view (the active default view displays as dark blue), and then assign the view with the following menu commands: Left pane: Wellbore > Pore Pressure Right pane: Wellbore > Fracture Gradient

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5. Select Tools > Defaults > Bit Sizes. The default values you supply are used to construct the drop-down list in the Casing Scheme spreadsheet’s Hole Size cell. In general, you only use this feature to add commonly used bit sizes. Click OK to apply any changes and dismiss the dialog box.

6. Select File > Save to save the E3SOP1 Design, and then select File > Close to close the Design.


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Exercise 3: Reviewing/Specifying General Data 1. Open the E3SOP1 Design. 2. The Well depth is 16,330 ft MD. The Azimuth is 33 degrees. To check the Well depth and azimuth, select Wellbore > General. You can also access this dialog box using the Wizard. 3. Review and update the casing scheme by using Wellbore > Casing and Tubing Scheme and the following data: Note •

Values for the Shoe Depth and Mud at Shoe are rounded up.

•

Values for the Top of Cement will be updated.

•

The 7” Production Casing will become a Production Liner; therefore, the 9 5/8” will be changed to Production Casing type.

OD(in) /Type/Name

Hole Size (in)

Hanger (ft)

Shoe (ft)

TOC (ft)

Mud at Shoe (ppg)

30” Conductor Casing

36

30.0

600

430

8.6

24” Surface Casing

26

30.0

1,150

500

8.6

18 5/8” Intermediate Casing

22

30.0

3,030

1,660

9.2

16” Intermediate Casing

17.5

30.0

9,185

4,480

11.6

13 5/8” Protective Casing

14.750

30.0

12,020

8,315

14.0

9 5/8” Production Casing

12.25

30.0

14,620

10,750

15.1

7” Production Liner

8.5

14,320

16,330

14,320

11.0

4. Copy the pore pressure data from the Excel spreadsheet titled porefrac.xls. Your instructor will provide this file. Insert the rows above any existing rows in Wellbore > Pore Pressure with the data provided in the Excel spreadsheet. 5. Copy the fracture gradient data from the Excel spreadsheet titled porefrac.xls. Copy over any existing rows in Wellbore > Fracture Gradient with the data provided in the Excel spreadsheet.

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Note You can input either pressure or EMW and the StressCheck software calculates the other. In the porefrac.xls spreadsheet, pressure is blank, and the StressCheck software calculates the pore and frac pressure values based on EMW.

6. Enter geothermal gradient values to specify the Wellbore temperature. The surface ambient temperature is 80 degree °F, the mudline temperature is 40 degree °F, and the temperature at TD is 250 degree °F. Specify additional temperature data as follows: • 200 degree °F at 11,130 ft TVD • 240 degree °F at 12,630 ft TVD 7. Import Wellpath data from the file titled “E3SOP1_Wellpath for EDM training.txt”. In what format must the file be prior to importing it? Hint See StressCheck Help.

Review the wellpath data. 8. Specify the following bending dogleg in addition to any planned dogleg severity. Enter 1°/100 ft between 1,700 and 5,970 ft MD, between 6,300 and 9,690 ft MD, and between 10,500 and 16,330 ft TD. a) How can you specify this? b) What is the Wellbore > Dogleg Severity Overrides data used for? 9. Select Wellbore > Production Data, and specify packer fluid and placement. The Well is perforated at 16,100 ft MD with a packer at 15,200 ft MD. The completion fluid is water with a density of 8.6 ppg. Assume the Well will produce gas with a gradient of 0.1000 psi/ft. What is the fluid gradient specific gravity? StressCheckTM Software Release 5000.1.13 Training Manual

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10. Save the E3SOP1 Design.

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Exercise 3 Answers 1. In the Well Explorer, navigate to the E3S0 Well, and then double-click on the E3SOP1 Design to open it. 2. Select Wellbore > General to specify the Well depth and azimuth. The Well depth is 16,330 ft MD. The Azimuth is 33 degrees. Note Throughout the remainder of the exercises, click OK to apply changes and dismiss the current dialog box.

3. Select Wellbore > Casing and Tubing Scheme and enter the following:


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4. In the Excel spreadsheet, highlight the rows you want to copy and press Ctrl-C. Select Wellbore > Pore Pressure, place the cursor in the first row left cell, and then press Ctrl-V to paste the rows.

Click the upper left cell, and then press Ctrl-V to paste the pore pressure data.

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5. In the Excel spreadsheet, highlight the rows you want to copy and press Ctrl-C. Select Wellbore > Fracture Gradient, place the cursor in the first row left cell, and then press Ctrl-V to paste the rows.

Click the upper left cell, and then press Ctrl-V to paste the fracture gradient data.


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6. Select Wellbore > Geothermal Gradient.

Specify basic formation temperature data.

Specify additional formation temperature data. These additional temperatures can be used to characterize a more complex formation temperature profile or seawater temperature profile.

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7. Select Wellbore > Wellpath Editor, and then select File > Import > Wellpath to open the Import Wellpath File dialog box. Navigate to the location of the “E3S0P1_Wellpath for EDM training.txt” file, select it, and then click Open. Review the imported wellpath data. Alternatively, you can copy and paste data into the Wellpath Editor. The following rules associated with copy/paste of wellpath data can be found in the “Wellpath (Import)” topic of StressCheck Help: • The file must be tabular delimited text that uses using any combination of spaces, tabs, or commas as field delimiters. • Column 1 is reserved for measured depth, and measured depth values must be in increasing order and positive values. • Column 2 is reserved for inclination. • Column 3 is reserved for azimuth, and azimuth values must be 0.0° ≤ AZ ≤ 360.0°. Note EDM Data Transfer File imports are not supported from paths or file names that contain apostrophes. Make sure you do not use apostrophes in file names or directory names.

8. Select Wellbore > Dogleg Severity Overrides to define intervals of wellpath curvature independent of the deviation profile defined in Wellbore > Wellpath Editor.

a) Dogleg overrides can be accomplished in two ways. One method uses the Wellbore > Wellpath Editor, and the other method uses the Wellbore > Dogleg Severity Overrides spreadsheet. Do not enter the override in both places. To use the Wellpath Editor, enter the override in the Max DLS column. Do not enter the additional dogleg in the DLS column because the DLS values describe the trajectory.


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b) This data is used in calculating bending stress as long as this dogleg is greater than the dogleg due to bending indicated in the Wellbore > Wellpath Editor and the calculated dogleg due to buckling. 9. Select Wellbore > Production Data.

To determine the gas/oil gradient sg, select the Gas/Oil Gradient option and press F4 to access the Convert Gas Gradient Units dialog box.

Highlight the unit that you want to momentarily convert the unit value to. Click OK to close the dialog box.

10. Press Ctrl-S to save the E3SOP1 Design.

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Exercise 4: The Design Process 1. Select the 9 5/8” Production Casing to design. 2. Select Tubular > Design Parameters and specify the following for each tab: Design Factors Tab Pipe Body Burst

Connection 1.100

Burst/Leak

Axial

1.100 Axial

Tension

1.300

Tension

1.300

Compression

1.300

Compression

1.300

Collapse

1.000

Triaxial

1.250

Analysis Options Tab Min Internal Drift Diameter

8.500

Single External Pressure Profile

Check box selected.

Temperature Deration

Check box selected.

Limit to Fracture at Shoe

Check box selected.

Buckling

Check box selected.

Use Burst Wall Thickness in Triaxial

Check box not selected.


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3. Select the Tubular > Initial Conditions > Cementing and Landing tab, and specify post-cementing hydrostatic profiles for certain burst, collapse, and axial loads to include: Mix-Water Density

8.33

Lead Slurry Density

15.20

Tail Slurry

Check box selected.

Tail Slurry Density

15.60

Tail Slurry Length

500

Displacement Fluid Density (1)

14.80

Float Collar Depth, MD

14,620

Applied Surface Pressure


Float Failed


Landing Data (Pickup and Slackoff Force) (2)

0

(1)

14.8 ppg is used so the ECD does not exceed the fracture gradient while displacing cement slurry. (2) Do not apply pickup or slackoff forces.

What is the initial Temperature Profile assumed for this string?

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4. Select the Tubular > Burst Loads > Select tab, and specify the following burst loads for the 9 5/8” string. Then, select the Edit tab to specify the burst loads details (the pick-list in the Edit tab controls which parameters are displayed). Use the default values unless otherwise specified. Internal Profile Displacement to Gas

Influx Depth at section TD, 16,330 ft, Gas/Oil Gradient, 0.1000 psi/ft, Fracture Margin of Error, 0.00 ppg, Mud/Gas Interface estimated at surface, Mud Weight, 11.00 ppg

Gas Kick Profile

Influx depth at section TD, 50 bbl influx, with 0.5 ppg kick intensity, 11.0 ppg maximum mud weight, 0.7 kick gas gravity, 0 ppg fracture margin of error, 5” drill pipe, and 1,000 ft of 6.75” collars

Lost Returns with Water

Leave as default

Green Cement Pressure (Bump Plug) Test

1,000 psi

Drill Ahead

Hanger Depth, 30 ft, TOC Depth, MD, 10,750 ft, Shoe Depth, MD, 14,620 ft, MW Next Hole Section, 11.0 ppg, ECD, 0.30 ppg Note: Click Yes if prompted to copy Drill Ahead data from Burst to Collapse load.

Tubing Leak

Leave it as default

Injection Down Casing

Injection Pressure, 5000.0 psi, Injection Density, 8.33 ppg

External Profile Fluid Gradients w/ Pore Pressure (External Profile)

Fluid Gradients w/ Pore Pressure, 8.33 ppg above TOC (to analyze worst case) and 8.33 ppg below TOC, Pore Pressure In Open Hole Below TOC check box not selected


9-25


5. Select the Tubular > Collapse Loads > Select tab, and specify the following collapse loads for the 9 5/8” string. Then, select the Edit tab to specify the collapse loads details (the pick-list in the Edit tab controls which parameters are displayed). Use the default values unless otherwise specified. Internal Profile Full/Partial Evacuation

Default mud weight, and 9,000 ft mud level

Cementing

Use defaults

Lost Returns with Mud Drop

Lost Returns Depth, 15,784.9 ft, Mud Weight, 11 ppg

Above/Below Packer

Pore Pressure at Perforation Depth, 3000 psi, Density Above Packer, 8.60 ppg, Density Below Packer, 2.0 ppg, Fluid Drop Above Packer check box selected

Drill Ahead (Collapse)

Hanger Depth, 30 ft, TOC Depth, MD, 10,750 ft, Shoe Depth, MD, 14,620 ft, MW Next Hole Section, 11.0 ppg, ECD, 0.30 ppg

External Profile Fluid Gradients w/ Pore Pressure

Fluid Gradient Above TOC, 15.10 ppg, Fluid Gradient Below TOC, 15.10 ppg, Pore Pressure In Open Hole Below TOC check box not selected.

6. Select Tubular > Axial Loads > Select tab, and then specify the following axial loads:

9-26

Running in Hole - Avg Speed

3.00 ft/sec

Overpull Force

100,000 lbf

Pre-Cement Static Load Applied Force

0 lbf

Post Cement Static Load

Check box selected

Green Cement Pressure Test

1,000 psi

Service Loads

Check box selected



7. Save and close the E3SOP1 Design. What is the wellhead pressure for each load? Hint Select the View menu options.

What is the expected mud level (during Lost Return with Mud Drop scenario)? 8. Perform a Graphical Design. Assume you want to use the same casing weight and grade along the length of the entire string. Hint Display the Design Plots in the Design tab.

a) What pipe is initially selected? b) Which Design mode (burst, collapse, axial, triaxial) is more critical to the Design? c) If you have some pipe inventories of 10,000 ft of 9 5/8”, 53.5 ppf, L80 casing, LTC connection, could it be used for this Well in combination with the initial solution? How many feet of this pipe would you use otherwise? Does the LTC connector satisfy the design criteria (Design Factors)? 9. Select a VAM TOP from the Special Connection Inventory (catalog). Does the 9 5/8”, 53.50 ppg, L-80 VAM TOP string connection satisfy the design criteria (Design Factors)? 10. Save the E3SOP1 Design.


9-27


Exercise 4 Answers 1. Select Tubular > Current String to select the casing string to design. Alternatively, select the string from the Wizard.

Select Tubular > Current String, and then select 9 5/8” Production Casing. - or Select 9 5/8” Production Casing from the Select String drop-down list.

2. Review Design parameters Design Factors and Analysis Options.

Coupling Design factors use pipe body Design factors if coupling Design factor fields are empty.

9-28




9-29


3. Select Tubular > Initial Conditions > Cementing and Landing tab. This data is specified on a per string basis.

Select the Tail Slurry Density check box to allow entry of tail slurry data.

9-30



Select Tubular > Initial Conditions > Temperature tab.

Select the Temperature tab to view the initial Temperature Profile of the string. The default values correspond to the undisturbed Temperature Profile.


9-31


4. Select Tubular > Burst Loads to designate burst loads for the 9 5/8” string.

A check box is associated with each load case you want to use. Details of each load case are specified by using the Edit tab.

The selected External Profile will be used for all burst loads because the Single External Pressure Profile check box is selected on the Tubular > Design Parameters > Analysis Options tab.

9-32



Select the Displacement to Gas load from the dropdown list, and enter data as specified to define the load case.

Select the Lost Returns with Water load from the pull-down list, and enter data as specified to define the load case.


9-33


Select the Gas Kick Profile load from the dropdown list, and enter data as specified to define the load case.

Select the Tubing Leak load from the drop-down list, and review the load case values.

9-34



Select the Injection Down Casing load from the drop-down list, and enter data as specified to define the load case.

Select the Green Cement Pressure Test load from the drop-down list, enter 1000 psi Test Pressure, and then review the other load case values.


9-35


Select the Drill Ahead (Burst) load from the drop-down list, and enter data as specified to define the load case.

Click Yes if prompted to copy Drill Ahead data from Burst load to Collapse load.

Select the Fluid Gradients w/ Pore Pressure load from the drop-down list, and review the load case values. Click OK to apply changes and close the dialog box.

9-36



5. Select Tubular > Collapse Loads to designate collapse loads for the 9 5/8” string.

Select the check box associated with each load case you want to use. Details of each load case are specified using the Edit tab.

Select the Full/Partial Evacuation load case from the dropdown list, and enter data as specified to define the load case.


9-37


Select the Cementing load from the dropdown list and review the default data for this load case.

Select the Lost Returns with Mud Drop load from the dropdown list and enter data as specified to define the load case.

9-38



Select the Above/Below Packer load from the pull-down list, and enter data as specified to define the load case.

Select the Fluid Gradients w/ Pore Pressure load from the drop-down list and enter data as specified to define the load case.


9-39


Select the Drill Ahead (Collapse) load from the drop-down list and enter data as specified to define the load case.

Click OK to apply changes and close the dialog box.

6. Specify the axial loads using Tubular > Axial Loads.

On the Select tab, select the axial loads, and specify values as shown.

Click OK to apply changes and close the dialog box.

7. Press Ctrl-S and then select File > Close to save and close the E3SOP1 Design.

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Select File > Open, select the E3SOP1 Design, and click OK. Wellhead Pressures (psi) can be viewed using View > Tabular Results > Burst Loads.


9-41


To determine the mud level, refer to the Tubular > Collapse Loads > Edit tab for Lost Returns with Mud Drop load case (see page 9-38). The Mud Drop Level is 1,958.0 ft MD. This is the measured depth level of mud required to balance the formation pore pressure. (This mud drop is calculated by assuming the hydrostatic column of mud in the hole equilibrates with a specified pore pressure at a specified depth.)

The Lost Returns with Mud Drop load displays 1958 ft as the calculated mud drop.

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8. To perform the Graphical Design, divide the Design tab into four panes (select Window > Split), and enable a simultaneous view of multiple plots. Starting with top left to top right, then lower left to lower right, select View > Design Plots > Burst, View > Design Plots > Collapse, View > Design Plots > Axial, and View > Design Plots > Triaxial. (Close the Well Explorer to maximize the view area.)


9-43


Double-click any Design Plot pane background. A red line is drawn in all plots. This red line represents the strongest 9 5/8” pipe in the pipe inventory that satisfies the loading conditions. To view the pipe rating and grade, place the cursor over the Pipe Rating line, and click the left mouse button. The pipe size, weight, and grade is displayed in the status bar.

To change the pipe weight, grade, or size, right-click the pipe rating line you want to change. Drag the pipe rating line to the desired position. When a pipe is changed in one plot, the change is applied to the other plots.

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a) Select the String and Connection tab, and split the tab into two horizontal panes. Hint Double-click the horizontal splitter in the upper right corner of the main view area, or drag the horizontal splitter bar to the desired location to adjust the viewing area.

On the top pane, select Tubular > String Sections. On the bottom pane, select Tubular > Connections.


9-45


The top pane (String Sections table) displays the default pipe selected, 9 5/8”, 53.50 ppg, Q-125 grade, with a cost of $437,116. Double-click the small bar in the upper-right corner to split the pane horizontally.

The Tubular > String Sections spreadsheet is automatically entered.

From the bottom pane (Connections table), select BTC (Buttress Connection) as the pipe connection Type, and then tab out of the field. Notice that the total casing and connection cost increased to $515,786.

The total cost of casing and tubing increased by $78,670 when BTC type connectors are used.

b) The Collapse load controls the Design. 9-46



c) From the String and Connection tab, edit the String Sections and Connections tables as follows: Update the Tubular > String Sections and Tubular > Connections spreadsheets.

Notice that the 9 5/8”, 53.50 ppg, L-80, LTC connection is under designed for the specified design criteria. Connection Safety Factor (Abs) = *1.25 (the asterisk indicates the Connection Safety Factor (Abs) is less than the minimum Allowable Safety Factor (Design Factor).


9-47


Select the Design tab. Notice that changes made in the String and Connection tab are automatically applied to all Design plots. Notice that the 9 5/8”, 53.50 ppf, L-80 string section is under designed for both Collapse and Triaxial loads.

9-48



Select the Min ASF tab. Select View > Tabular Results > Min Safety Factors.

Notice that both connections (LTC) Axial, jump out failure, and pipebody (9-5/8”, 53.50 ppg. L-80) Collapse, Triaxial under design conditions are flagged. The legend at the bottom of the table states that values flagged with an asterisk indicate the Safety Factor is below the Design Factor. The lowest Absolute Safety Factor after comparing connection and pipebody absolute safety factors is reported for any depth of interest. Connection absolute safety factors are recognized by the letter attached indicating possible failure mode (for example, L, F, J).


9-49


Select the Design tab. On the Triaxial Design plot, drag the horizontal line of the Pipe Yield Strength line upward until the Design Load Line is to the left of the Pipe Yield Strength line as shown below. Drag the horizontal line of the Triaxial plot Pipe Yield Strength Line. Notice that the Collapse Design plot adjusts automatically with the change. You can drag any vertical/horizontal pipe rating / yield strength lines.

9-50



Select the String and Connection tab.

About 8,900 ft of L-80 pipe can be used.

Notice that the 9 5/8”, 53.50 ppg, L-80, LTC connection is still flagged as under designed for the specified design criteria. Connection Safety Factor (Abs) = *1.25, which is less than the Axial Tension Design Factor of 1.30.

9. Select the Work tab. Select Tubular > Special Connections Inventory. Select Edit > Import from Catalog, and then select VAM TOP from the list of catalogs on the left side of the dialog box. With the VAM TOP catalog selected, highlight (select) the VAM TOP, 9 5/8”, 53.50 ppg, L-80 connector.


9-51


Click Import to add it to the Special Connections table. Select VAM TOP special connections inventory catalog.

Select (highlight) the VAM TOP 9 5/8”, 53.50 ppg, L-80 connection . Click Import to add the connection to the Special Connections

Note The red shading of the Special Connections listings indicates that there is no pipe of the same size, weight, and grade in the Pipe Inventory.

Select the String and Connection tab. Replace the LTC connection Type with VAM TOP. Notice the Connection Safety Factor (Abs) now satisfies the design loading conditions.

10. Click the Save icon (

9-52

) to save the E3SOP1 Design.



Exercise 5: Minimum Cost 1. Set the Minimum Cost search parameters to look at the most conservative constraints, where both Triaxial Design criteria and the API Burst, Collapse, and Axial limits are not exceeded. Select one casing section that has a minimum section length of 1,000 ft. 2. Change the Cost Factor for T-95 grade material to 1.60. 3. Execute the Minimum Cost search. a) What pipes are selected by the minimum cost search? b) Are these likely to be appropriate for your Design? c) Select BTC connections. Is there any problem using the BTC connection? d) How would you verify in-house connection test data? 4. How much was saved on the cost compared to the initial Q-125, BTC solution? 5. Save the E3SOP1 Design.


9-53


Exercise 5 Answers 1. In the Tubular > Minimum Cost dialog box, enter parameters as seen below, and then click OK. Refer to online help for further information.

Select the Tubular > Minimum Cost > Parameters tab and enter the following.

Select the Tubular > Minimum Cost > Design tab, and select areas (gray) as seen here.

9-54



2. Select Tools > Default > Cost Factors. Change the T-95 grade cost factor to 1.60, and then click OK.

Click the T-95 Cost Factor field and change the default to 1.60.

3. Select View > Design Plots > Minimum Cost.

a) Pipe selected is: 9 5/8” OD, 53.50 weight, P-110 grade. Therefore, the minimum cost is obtained using P-110 grade pipe for the 9 5/8” OD string. Notice that the connector table inputs are reset to undefined after executing Minimum Cost.


9-55


b) Yes, based on the Design plots, all design load lines are to the left of the pipe rating lines.

9-56



Select the Work tab, and then open the View > Triaxial Check > Design Limits plot. Notice that all loads are within the unibiaxial/triaxial limits.

c) Select the String and Connection tab. From the Connections table Type pick-list, select BTC.

Select BTC as the connection type.


9-57


Select the Min ASF tab. Although the design satisfies the design criteria, using BTC connections weakens the design because the burst safety factor is connection critical, and the possibility of a connection leak increases.

9-58



d) Select the Work tab, then select the View > Triaxial Check > Design Limits plot. Right-click the plot and select In-House Connection Test Data to open the Maximize dialog box.

Open the “IN-HOUSE Connection TD.txt” file. Press Ctrl-A to select all the text, then press Ctrl-C to copy the content into the Windows clipboard (see StressCheck Help for more information).

Press Ctrl-A, then press Ctrl-C to copy the contents of the text file into the Windows clipboard.


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Select the top left editable table cell on the Maximize dialog box, then click Paste.

Click Paste to add the contents of the Windows clipboard into the dialog box.

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Click OK to apply the test data to the Design plot. You can then compare the load distribution against the connection test envelope.

Notice that Metal Seal is added to the Design plot.

Note In-House Connection Test data is not retained after a Design is closed.

4. The cost savings is $515,786 - $473,878 = $41,908. 5. Click the Save icon (

) to save the E3SOP1 Design.


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Exercise 6: Analyzing Results 1. Select the Schem tab, and split the tab into two horizontal panes. On the top pane, select Wellbore > Casing and Tubing Scheme. On the bottom pane, select View > Well Schematic. Configure the Well schematic to show the title, cement, tapered string, reference depths, fluid, casing float shoes, the TOC for liners and casing strings, top of the liner, and non-deviated. Change the title of the schematic to StressCheck Training. Hint Use the right mouse button.

2. Split the Burst and Collapse tabs into four equal panes each. Populate these panes (starting with top left to top right, then lower left to lower right) with the View > Burst Plots and View > Collapse Plots as follows: Differential Pressures, Load Line, Pressure Profiles, and Temperature Profiles, respectively. a) Which burst loads contribute to the burst load line? What is the string temperature profile during the Displacement to Gas scenario? b) Which collapse loads contribute to the collapse load line? 3. Select the Axial tab and split the view into four panes (starting with top left to top right, then lower left to lower right) with the View > Axial Plots as follows: Load Profiles - Apparent (w/Bending), Load Line, Service Load Profiles - Apparent w/Bending, and Service Load Lines. a) Which load cases and axial force directions (tension/compression) contribute to the service load line throughout the Well? 4. Split the Triaxial tab into four equal panes. Populate these panes (starting with top left to top right, then lower left to lower right) with the View > Triaxial Check plots as follows: Load Line, Safety Factors, Design Limits, and Von Misses Equivalent Plot.

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5. Momentarily, do not include the effect of temperature on yield strength, and the effect of buckling, in your Design. Hint Apply these changes while viewing the Design plots.

a) Do you need to change your Design? b) Check both temperature deration and buckling prior to saving the Design. 6. Save the E3SOP1 Design.


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Exercise 6 Answers 1. Split the pane and apply views as seen below. Right-click on the Well Schematic to access the Well Schematic Properties dialog box. In the Well Schematic Properties dialog box, select the items to display on the schematic, then click OK.

Right-click the Schematic, and then select Properties.

Change the Title name, then select the check boxes associated with the items you want displayed on the Well Schematic. This dialog box is also accessible via the Edit > Properties menu path.

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Click OK to view the changes to the schematic.


2. On the Burst and Collapse tabs, split the panes and apply views as seen below. Refer to the plots on the Burst and Collapse tabs to determine the loads that define the burst and collapse load lines. Note If a plot legend covers most of the viewing area, right-click an empty area on each graph, and then select Properties from the drop-down menu. On the Graph tab of the dialog box, deselect the Show Legend check box to see all plot data.

a) The Burst Load Line plot is based on the Displacement to Gas and Tubing Leak burst loads. The Burst Load Line plot is a compilation of burst differential pressure curves. In this case, the burst load line is a compilation of the Displacement to Gas and Tubing Leak load lines.

The assumed string temperature profile during Displacement to Gas scenario shows a typical temperature profile, with lower temperature at the mid/lower casing section, and higher temperature in the mid/upper casing section, compared to the undisturbed temperature profile. StressCheckTM Software Release 5000.1.13 Training Manual

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b) The Collapse Load Line plot is based on the Lost Returns with Mud Drop, Full/Partial Evacuation, and Above/Below Packer collapse loads.

The Collapse Load Line plot is a compilation of collapse differential pressure curves. In this case, the collapse load line is a compilation of the Lost Returns with Mud Drop, Full/Partial Evacuation, and Above/Below Packer load lines.

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3. On the Axial tab, split the panes, and apply views as seen below. Tensile/Compressive axial loads display

The Service Load line draws over the Lost Returns with Water and the Above/Below Packer loads.

All axial service loads are displayed in absolute values to facilitate identification of the maximum loads, including Lost Returns with Water, Injection Down Casing, and Above/Below Packer.


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a) The service load line is positive (Tension), down to approximately 7,000 ft MD due to the Lost Returns with Water and Injection Down Casing axial load component. The Service Load line becomes negative (Compression) down to approximately 10,500 ft MD due to the Above/Below Packer axial load component, and finally it shifts back to positive down to TD due to Lost Return with Water and Injection Down Casing axial load component.

Service Loads line

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4. Split the Triaxial tab into four panes, and place one plot in each pane as shown below.

In the Design plot, the Von Mises and the API failure criteria plot together. The Von Mises plot envelope in this case is approximate. Consequently, sometimes failure points plot inside the envelope.

The Von Mises Equivalent Stress plot is totally pressure independent; that is, the strength of steel does not depend on the hydrostatic pressure.

Note: Always validate your visual interpretations with tabular results, as well as with the Von Mises equivalent stress.


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5. Select the Tubular > Design Parameters > Analysis Options tab, and deselect the Temperature Deration and Buckling check boxes. Hint You can select and deselect the temperature deration and buckling check boxes, click Apply, and then observe the effect on the plots.

When finished, verify Temperature Deration and Buckling options are selected in the Tubular > Design Parameters > Analysis Options tab and then click OK.

Deselect the Temperature Deration and Buckling analysis options.

a) No, deselecting temperature deration and buckling makes the design criteria less critical.

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Notice that Collapse Load shifts slightly away from the design limit (Triaxial Safety Factors). Similarly, the Above/Below Packer Load shifts slightly upward on the Von Mises plot. Collapse load shifts slightly right, away from the design limit (Failure Criteria).

Above/Below Packer shifts slightly upward (within the envelope), away from the unibiaxial collapse limit. Note It is always recommended to support any graphical interpretation with tabular results. It is also recommended to verify Design Parameter settings prior to reaching design conclusions.

6. Select the String and Connection tab, then click the Save icon ( ) to save the E3SOP1 Design.


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Exercise 7: Tables and Reports 1. Using the Print Preview feature (available if you have printer drivers set up on your PC), investigate the options for printing results from the desktop. 2. What is the minimum burst absolute safety factor for the 9 5/8” casing? Be sure to select casing 9 5/8” 53.50 ppf, P-110. Verify the BTC Connection Type (P-110 Grade) is specified in the Connections table. 3. What is the minimum triaxial absolute safety factor for 9 5/8” casing, and what is the minimum triaxial normalized safety factor? What is the ratio (Abs/Norm) between these values? Why? 4. What are the four minimum absolute safety factors at the top of cement? Hint Look at both free and cemented pipe at the TOC. Determine the TOC using Wellbore > Casing and Tubing Scheme and/or View > Well Schematic.)

5. At what depth is wear most critical for burst and collapse? What is the maximum allowable wear at this depth? 6. What overpull could you pull if the casing became stuck at 14,000 ft MD while running in? What would be the axial absolute safety factor if this overpull was applied? 7. What is the axial force at the wellhead when the casing is cemented? 8. Which load case results in the minimum collapse absolute safety factor? At what depth does this occur? 9. Which load case(s) indicate buckling conditions? How can reported buckling conditions be prevented in the design? 10. What are the pipe ratings for the casing?

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11. Set up a new report, and name the report Wellbore Data. Select the Portrait format with multiple items on each page. Select Print Preview (if available) to display the report on your screen. Include the following items in the order presented: • • • • • • • •

General Data Well Schematic Casing and Tubing Scheme Data Pore Pressure Data Fracture Gradient Data Pore, Fracture & MW Plot Deviation Data Geothermal Gradient Data

12. Save and close Design E3SOP1.


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Exercise 7 Answers 1. Select File > Print Preview. When finished, click Close. Select what you want to print from the drop-down list.

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2. On the String and Connection tab, verify BTC is specified in the Type drop-down list in the Connections table. Verify the connection type BTC is specified as the connection Type.

Select the Work tab, and then select View > Tabular Results > String Summary. The minimum absolute burst safety factor for the top section is 1.51 L (that is, the “L” denotes that the design is connection (leak) critical).

3. Click the Normalized SF icon (

The absolute Triaxial safety factor is 1.60.

).

Notice that the minimum Triaxial Normalized safety factor is 1.28.

The ratio between the absolute and normalized safety factors is 1.25 because the Normalized SF = Absolute SF/Design Factor (1.60/1.28). You can verify that 1.25 is the specified Design factor (Tubular > Design Parameters > Design Factors tab). StressCheckTM Software Release 5000.1.13 Training Manual

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4. Select the Schem tab and view the Casing and Tubing Scheme table or the Schematic. Notice that TOC = 10,750 ft MD. TOC for 9 5/8” Production Casing is 10,750 ft.

Select the Work tab, and then select View > Tabular Results > Min Safety Factors. Make sure you view absolute safety factors. Make sure you view the absolute safety factors. Click the Normalized SF icon again ( ) before selecting the Minimum Safety Factor table.

Burst minimum absolute safety factor is 1.58.

Collapse minimum absolute safety factor is 1.17. Axial minimum absolute safety factor is 3.15. Triaxial minimum absolute safety factor is 1.85.

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5. From the Work tab, select View > Tabular Results > Max Allowable Wear table.

The max allowable wear is most critical for burst at TD, with a rating of 37.6% maximum wear (% of wall thickness).

The max allowable wear is most critical for collapse at TD, with a rating of 1.1% maximum wear (% of wall thickness).


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6. From the Work tab, select View > Tabular Results > Max Allowable Overpull. The axial SF is the Design safety factor of 1.3. The Axial Design safety factor is specified on the Tubular > Design Parameters > Design Factors tab.

The maximum overpull at 14,000 ft MD is 761,107 lbf.

7. From the Work tab, select View > Tabular Results > Axial Loads. The axial force at the wellhead when the casing is cemented is approximately 500 kips.

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8. From the Work tab, select View > Tabular Results > Minimum Safety Factors.

Use this key to determine which codes are associated with each load case.

The minimum absolute collapse safety factor results from the Above/Below Packer load case and is 1.03 at 14,620 ft TD.


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9. From the Work tab, select View > Tabular Results > Triaxial Results.

From the Load pick-list, check all loads. (This pick-list is only available when the Triaxial Results table or a custom load is displayed and active.)

With the Triaxial Result table in view, select from the Load pick-list to check all loads.

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The Tubing Leak load triaxial results reports a buckled pipe length of 9,883 ft, and additional pickup to prevent buckling of 321,957 lbf.

The Above/Below Packer load triaxial results reports buckling conditions as well. High delta temperature is the primary reason that causes the buckling condition in combination with high internal pressure.


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Momentarily, with the Triaxial Results for Tubing Leak displayed, select the Tubular > Initial Conditions > Cementing and Landing tab. Select the Pickup Force option, and then enter a pickup force ≥ the reported pickup force to prevent buckling during tubing leak event. Click Apply, then notice the buckling condition for this scenario is removed. With the Triaxial Results table active, select Tubing Leak from the Loads pick-list.

From the Tubular > Initial Conditions > Cementing and Landing dialog box, select the Pickup Force option, and then enter a pickup force of 321957 lbf. Click Apply to see the buckling condition removed.

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From the Tubular > Initial Conditions > Cementing and Landing tab, reset the Pickup Force to 0 lbf. Click OK to dismiss the Initial Conditions dialog box and return to the Triaxial Results table.

Reset the pickup force to 0 lbf.

10. From the String and Connection tab, select either the String Sections or Connections spreadsheet, and then highlight a row or click in a cell on the row. Click the Ratings icon ( ) on the toolbar (or select Tubular > Ratings) to open the Ratings dialog box.


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11. Select Tools > Reports.

Click New, and then click Rename to create a report titled Wellbore Data.

Select the Contents tab, and then click Add to display the Add Contents dialog box. Select the items you want to add to the report. Standard Windows controls for multiple selections are available (mouse select with Shift or Ctrl keys). Click OK when you are finished selecting items. Use the Up and Down buttons to order the contents.

Indicate that you want Multiple Items Per Page, data for the Current String only, and Portrait format.

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Select File > Print Preview. Select the Wellbore Data report from the drop-down list. In the example below, the second page (Well Schematic) is shown. Familiarize yourself with the report controls.

12. Press Ctrl-S, and then select File > Close to save and close the Design. StressCheckTM Software Release 5000.1.13 Training Manual

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Exercise 8: Sensitivity Analysis In this exercise, you will perform the following design checks with sensitivity analysis of: • • •

Special pipe tubular properties Taper string casing configuration High collapse casing exposed to a high collapse loading condition

Special Pipe Tubular Properties In this analysis, you will perform a design check using special pipe tubular properties applied to a corrosive environment (CO2 service). Corrosion is a major problem in gas fields with CO2 for production strings. 13 CR as a stainless steel material is available for these types of conditions. 1. Open planned Design E3S0P1. Save the Design as E3S0P1_13CR. 2. Define a temperature deration schedule named 13 CR. Specify the deration of the material’s yield strength as follows:

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Temperature DF

Correction Factor

77.0

1.00

122.0

0.98

212.0

0.94

302.0

0.92

392.0

0.89



3. Define a new material named 13 CR, and then enter the following material mechanical properties for this new material: Material Name

13 CR

Young's Modulus (psi)

29,000,000

Poisson's Ratio

0.29

Density (lbm/ft3)

490

Expansion Coefficient (E-06/F)

6.1

* Temperature Schedule Name: 13 CR * StressCheck version 5000.x and beyond has modified the association to the Temperature deration schedule. It will be defined at the Grade table instead of the Material table. Also, both anisotropic yield columns (radial and hoop) will be displayed in the Grade table.

4. Define a new Grade named VM 110 13 CRSS. Enter the following casing/tubing physical properties: Grade or Name

VM 110 13 CRSS

Yield (psi)

110,000

UTS (psi)

110,000

Material

13 CR


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5. Define a Pipe using grade VM 110 13 CRSS. Enter the following pipe properties:

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OD (in)

9.625

Weight (ppf)

53.5

Grade

VM 110 13 CRSS

ID (in)

8.535

Min Int Drift Dia (in)

8.5

Pipe Type

Standard

Burst (psi)

10,900 (calculated API)

Collapse (psi)

7,950 (calculated API)

Axial (lbf)

1,710,000 (calculated API)

UTS (psi)

110,000

Wall Thickness (% of Nom.)

87.5

Plain End Cost ($/ft)

Default



6. Define a connection named VAM SLIJ-II. Enter the following connection properties: Pipe Body OD (in)

9.625

Pipe Body Weight (ppf)

53.5

Pipe Body Grade

VM 110 13 CRSS

Connection Type

Other

Seal Type

MM

Connection OD (in

9.855

Burst (psi)

10,900

Tension (lbf)

1,275,000

Compression (lbf)

1,045,500

Max bending (degree/100 ft)

30

$/Cost

Default

7. Redefine the string section to use instead a 9 5/8”, 53.50 ppf, VM 110 13 CRSS casing: Top, MD (ft)

30

Base, MD (ft)

14,620

OD (in)

9 5/8

Weight (ppf)

53.500

Grade

VM 110 13 CRSS

8. Redefine the connection selected for 9 5/8”, 53.50 ppf, VM 110 13 CRSS. Instead, select the VAM SLIJ-II connection. 9. Observe: a) Does the 9 5/8”, 53.50 ppf, VM 110 13 CRSS, VAM SLIJ-II satisfy the design criteria? b) Do buckling conditions change as a consequence of applying different tubular properties?


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10. How can the new design tubular properties be shared at the Well Explorer Tubular Properties level? 11. Close the E3S0P1_13CR Design.

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Exercise 8 Answers: Special Pipe Tubular Properties 1. Open Design E3S0P1. Select File > Save As, and then save the Design with a new name, E3S0P1_13CR. 2. Select the Work tab, select Tubular > Tubular Properties > Temperature Deration, and enter the following temperature deration schedule for 13 CR: Enter five temperature deration points for 13 CR.

Note StressCheck 2003.16.1+ version series implemented the ability to define tubular properties within the application as an option in the Tubular menu. Other versions (2003.16.0, 2003.21) only allow definition of tubular properties from the Well Explorer. StressCheck version 5000.1 (and later) will support the 2003.16.1+ implementation.

3. Select Tubular > Tubular Properties > Materials, and then enter the following 13 CR material mechanical properties:


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4. Select Tubular > Tubular Properties > Grades, and then enter the following VM 110 13 CRSS Grade Properties:

Enter the new grade.

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5. Select Tubular > Pipe Inventory, and then enter the following pipe using VM 110 13 CRSS Grade:

Enter the new pipe with the grade you created in the previous step.

6. Select Tubular > Special Connections Inventory, and then enter the following VAM SLIJ-II Connection properties:

Enter the new special connection.


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7. Select Tubular > String Sections, and then redefine the casing string as follows:

Assign the new VM 110 13 CRSS grade you created earlier to the string section.

After selecting a new Grade, refresh the material assigned for the grade selected. Select Tubular > Tubular Properties > Grades, and then reselect the 13 CR material from the pick-list.

Reselect the 13 CR material, then tab out of the cell to refresh the changes made in system memory.

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8. Select Tubular > Connections, and then select the VAM SLIJ-II connector as follows:

Assign the new connection type to the pipe section, then tab out of the cell.

9. Observe the following: a) Select View > Tabular Results > Min Safety Factors.

Notice that the 9 5/8”, 53.50 ppf, VM 110 13 CRSS, VAM SLIJ-II casing passed the design check. None of the reported absolute safety factors has exceeded the design factors.


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Burst safety factors are not connection critical (leak) anymore. However, you need to be cautious because the lowest known VAM SLIJ-II connection burst rating input is 10,900 psi, which is much higher than the initially applied BTC API Leak connection calculated rating of 9,160.8 psi. The Axial Safety factors are now connection critical (this is expected because of the near flush connection type applied). b) Select View > Tabular Results > Triaxial Results, Tubing Leak.

The Additional Pick up to Prevent buckling and Buckled Length initial values have changed (reduced) because of the different mechanical properties of the VM 110 13 CRSS grade compared to steel. 10. To share tubular properties at the Well Explorer Catalogs level, perform the following: Select the Work tab, and then select Tubular > Tubular Properties > Grades.

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Select Edit > Export to Catalog, and then select the VM 110 13 CRSS grade. Click the arrow button ( ) to add the new grade to the Well Explorer Tubular Properties. Click Close to dismiss the dialog box, and then press Ctrl-S to save the Design and apply the change.

Select the grade from the inventory, then click the arrow button to transfer the grade to the Catalog.

When the grade is exported to the Well Explorer Tubular Properties Grade table, the associated material and temperature deration data is transferred to the corresponding Well Explorer tubular properties tables. The ability to export grades to catalogs is dependent on the locked or unlocked status of the grade, material, and/or temperature deration. You cannot export a grade with any associated tubular properties locked. From the Well Explorer, double-click the Grades node ( the Grade table.

) to view

If the Locked check box is selected on the Grade, Material, or Temperature Deration table, you cannot export Grades to the Catalog. If it is locked, a small lock appears on the Well Explorer tubular property ( ).


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Notice that the Locked check box is not selected. The VM 110 13 CRSS grade has been exported, and the section type has been properly defined. Deselecting the Locked check box allows export to the catalog.

The export grade to catalog operation is also conditioned to User rights (see the “Application Security Tokens” topic in EDM Administration Utility Help). Note When new pipes defined in the Design pipe inventory table are exported to catalogs, the associated grade, material, and temperature deration are checked against the Well Explorer tubular properties. If the grade, material, or temperature deration exist in the Well Explorer Tubular Properties, only the pipe is exported to avoid duplicate tubular properties. If the grade, material, or temperature deration do not exist, then the pipe, grade, material, and temperature deration are exported.

11. Select File > Close to close the E3SOP1_13 CR Design. Click Yes if prompted, “Save changes to E3S0P1_13 CR*?”

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Taper String Design Check In this analysis, you will perform a design check using a taper string casing configuration. Taper string casing configurations are often used in a design (for example, tapered casing configurations can solve clearance issues in the production annulus when running completion tools). 1. Open planned Design E3S0P1. Save the Design as E3S0P1_Taper. 2. Create a 10 3/4” casing with a BTC connector, 9 7/8”, 62.80 ppf, P-110, 8.625” ID, VAM TOP taper string. The 10 3/4” string section length should be 1,000 ft. a) What is the lowest 10 3/4” weight and grade API pipe that satisfies the initial design criteria (loads analysis options and design factors) for the upper section? b) What design load mode drives the 10 3/4” casing weight and grade solution? c) Which is the most critical to the solution—the selected 10 3/4” pipe or 10 3/4” BTC connection? 3. Close the E3S0P1_Taper Design.


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Exercise 8 Answers: Taper String Design Check 1. Open Design E3S0P1. Select File > Save As, and then save the Design with a new name, E3S0P1_Taper. 2. From the Work tab, update the contents of the String/Connection, Casing and Tubing configuration and pipe inventory tables as follows: Select Tubular > String Sections, then remove current contents (that is, select the data row, and then press Delete to empty the table).

Select Tubular > Pipe Inventory. Select All from the pipe size pick-list. Select All from the pipe size pick-list.

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Select the first row, then select Edit > Insert Row. Enter the following: 9 7/8”, 62.80 ppf, P-110, 8.625” ID pipe information.

Select Wellbore > Casing and Tubing Scheme. Select 9 7/8” production Casing OD instead of current 9 5/8”.

Select Tubular > Special Connections Inventory. Select Edit > Import from Catalog, and then select VAM TOP from the list of catalogs on the left side of the dialog box. With the VAM TOP catalog selected, highlight (select) the VAM TOP, 9 7/8”, 62.80 ppg, P-110 connector.


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Click Import to add it to the Special Connections table. Select VAM TOP special connections inventory catalog.

Select (highlight) the VAM TOP 9 7/ 8”, 62.80 ppg, P-110 connection .

Click Import to add the connection to the Special Connections Inventory table.

Select the String and Connection tab, and then define the upper section of 10 3/4” pipe OD, 1,000 ft length. Initially pick the highest weight and grade, and then assign a BTC connector. Select the 9 7/8”, 62.8 ppf, P-110, pipe for the bottom section, and then assign a VAM TOP connector. Change the weight and grade for the 10 3/4” pipe section until the lowest safety factor is obtained for this section. After these steps are completed, select View > Tabular Results > Min Safety Factors, View > Design Plots and View > Triaxial Check > Safety Factors to review the effect of the change. Note The StressCheck software does not perform minimum cost design of Tapered Strings.

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Compare your selection with the selection shown below (10 3/4”, 51.0 ppf, C-95, BTC).

a) Select the Min ASF tab to view the minimum safety factors (absolute) table.


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Select the Design tab to view the design plots.

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Select the Triaxial tab to view the triaxial plots. To view the second string section design limits plot, right-click the “Design Limits - Section 1” plot and select Load/Section Selection from the drop-down menu. Select the Sections tab in the Properties dialog box that displays. Click OK to view Section 2. You may need to right-click on the plot again, and select Resize to view the plot in the reduced split-screen viewing area.

Right-click on the “Design Limits - Section 1” plot, and select Load/Section Selection from the dropdown menu. Click the Sections tab on the Properties dialog box that displays.


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Repeat the string section selection process on the Von Mises Equivalent Stress plot, and select Section 2.

You may need to right-click on the plot again, and select Resize to view the plot in the reduced split-screen viewing area.

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b) Apparently the Axial load design mode. c) Select the Work tab, and then select the View > Tabular Results > String Summary table.

The 10 3/4” BTC connection Axial Safety Factor (Abs) is the most critical condition to the taper design.

3. Select File > Close to close the E3S0P1_Taper Design. Click Yes when prompted to “Save changes to E3S0P1_Taper*?”


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High Collapse Casing In this analysis, you will perform a design check using a high collapse casing exposed to a high collapse loading condition. 1. Open planned Design E3S0P1. Save the Design as E3S0P1_HC. 2. Define a new pipe 9 5/8”, 53.50 ppf, P-110HC, and enter the following properties:

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OD (in)

9.625

Weight (ppf)

53.5

Grade

P-110HC

ID (in)

8.535

Min Int Drift Dia (in)

8.5

Pipe Type

Special

Burst (psi)

10900 (Calculated API)

Collapse (psi)

10550 (Special, high collapse)

Axial (lbf)

1710113 (calculated API)

UTS

125,000

Wall Thickness (% of Nom.)

87.5

Plain End Cost ($/ft)

Default



3. Define the following VAM SLIJ-II connection for the high collapse pipe: Pipe Body OD (in)

9.625

Pipe Body Weight (ppf)

53.5

Pipe Body Grade

P-110HC

Connection Type

Other

Seal Type

MM

Connection OD (in)

9.855

Burst (psi)

10,900

Tension (lbf)

1,275,000

Compression (lbf)

1,045,500

Max bending (degree/100 ft)

30

$/Cost

Default

4. Apply the new high collapse casing and connection associated to the design. 5. Does the new design tolerate a Full Evacuation scenario during production under Geothermal temperature conditions? 6. Close the E3S0P1_HC Design.


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Exercise 8 Answers: High Collapse Casing 1. Open Design E3S0P1, select File > Save As, and save the Design with a new name, E3S0P1_HC. 2. In the Work tab, perform the following. a) Select Tubular > Tubular Properties > Grades, and then enter the following grade:

Create a new Grade named P-110HC.

b) Select Tubular > Pipe Inventory and enter the following high collapse pipe information: Notice after entering the special pipe, the StressCheck software sorts the new row according to its weight, grade, and ID.

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3. Select Tubular > Special Connections Inventory and enter the following connection information:

4. Perform the following: a) Select Tubular > String Sections and apply the high collapse pipe.

Select P-110HC as the new grade for the string section.

b) Select Tubular > Connections and apply the VAM SLIJ connection to the 9 5/8”, 53.50 ppf, P-110HC pipe.

Select VAM SLIJ-II as the new connection for the pipe section.

5. Yes, the new Design tolerates a Full Evacuation scenario during production under geothermal temperature conditions.


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a) Select the Full Evacuation Production Loads check box on the Tubular > Collapse Loads > Select tab.

Select the Full Evacuation check box.

Select the Temperature tab, select Full Evacuation, and then select the Geothermal temperature option. From the Temperature tab, select Full Evacuation. Select the Geothermal option.

Click OK to accept the changes and close the dialog box.

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b) Select View > Tabular Results > Minimum Safety Factors. Notice that all safety factors (including collapse safety factors) satisfy the design criteria. The full evacuation load case is critical at the bottom of the high collapse 9 5/8” casing.

6. Select File > Close to close the E3S0P1_HC Design. Click Yes when prompted to “Save changes to E3S0P1_HC*?” StressCheckTM Software Release 5000.1.13 Training Manual

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Exercise 9: Independent Exercise 1. Design the 7” Production Liner. Use the same applicable loads (burst, collapse, axial) as applied to the associated production casing for the E3SOP1 Design. 2. What is the grade, weight, and connection recommended for the liner that satisfies the design criteria (default design factors)?

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Exercise 10: Template Exercise StressCheck Templates allow users to load recurring common data when creating Designs. Templates contain a combination of views, design criteria, and inventories settings. Once a template is assigned to a new Design, the assigned initial template cannot be replaced with another template. 1. Create a new template document called My Template from the Normal (System) Template in the StressCheck software. a) Add a new 9 7/8” OD pipe, 62.80 ppf, P-110, 8 5/8” ID to the default API pipe inventory. b) Increase the Legend default font size to 12. c) Rename the default “tab1” tab to Work, and add a new tab named Well Schematic. d) Predefine a Production casing string, design parameters. Use all default design factors for pipe and connection, except the pipe burst design factor. Instead, enter 1.2 rather than the 1.1 default value. Apply temperature deration and buckling as additional analysis options. Define the following Loads: for burst (Tubing Leak internal profile, and Fluids Gradient w/Pore pressure external profile; for Collapse, Gas Migration internal profile and Mud and Cement Mix Water external profile and for Axial, Overpull with 100,000 lbf and Service Loads). Define one section, 1,000 ft minimum section length, and apply default uni-biaxial boundaries except for the burst compression combine load (apply triaxial boundary) for the minimum cost Analysis. e) Save the template as a user’s template. f) Apply the My Template document to a new instant Design. How can you confirm the template settings are currently applied to the new Design?


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Exercise 10 Answers 1. Launch the StressCheck software, and then select File > Template > Open From Database.

From the File menu, select Template > Open From Database.

Open the Normal (System) template.

a) Select Tubular > Pipe Inventory. Select All from the pipe size

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pick-list, and then enter a new pipe OD.

Right-click the first row to highlight, and then select Insert Row to add a new row.

Enter 9 7/8” OD pipe, 62.80 ppf, P-110, 8 5/8” ID.


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b) Select Tools > Options, and then select the Legend check box. Click the legend Font button, and then update the font size to 12. Click OK, then click OK to apply the changes and close the Options dialog box.

Select Tools > Options, and then select the Legend check box. Click the Font button.

Enter 12, then click OK to apply the change.

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c) Select Tools > Tabs. Rename Tab1 to Work.

Click Rename, then enter the new tab name, Work.

Click New to add another tab, and then click Rename to name the new tab Well Schematic. Click Close to dismiss the dialog box.

Click New to create another tab.

Click Rename, and then enter the new tab name, Well Schematic.


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d) Select Wellbore > Casing and Tubing Scheme. Notice that only two columns are available: Name and Type. You can define all strings and string type combinations typically used in field operations. After the string(s) are defined, you can define design parameters and loads per each string type according to your Company Design Criteria policy. For example, define a string Production Casing. Select Production from the Name pick-list, and Casing from the Type pick-list.

Select Tubular > Design Parameters, and then redefine the burst safety factor as 1.2 instead of 1.1. Apply default values for all other design factors, and select Temperature Deration and Buckling as Analysis Options.

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Click OK to apply the changes.

Enter 1.2 as the Burst safety factor.

Select the Temperature Deration and Buckling Analysis Options check boxes.

Select Tubular > Burst Loads. Select Tubing Leak as the burst internal profile, and select Fluid Gradients w/ Pore Pressure as the external profile.


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Click OK to apply the changes and close the dialog box.

Select the Tubing Leak internal profile check box.

Select the Fluid Gradient w/ Pore Pressure external profile option.

Select Tubular > Collapse Loads. Select Gas Migration as the production load internal profile, and select Mud and Cement Mix-Water as the external profile. Click OK to save and close the dialog box.

Select the Gas Migration production load internal profile check box. Select the Mud and Cement Mix-Water external profile option.

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Select Tubular > Axial Loads, and then select Overpull Force. Apply 100,000 lbf as the default axial force, and then select Service Loads. Click OK to apply the changes and close the dialog box.

Select the Overpull check box, and then enter 100000 lbf.

Select the Service Loads check box.

Select Tubular > Minimum Cost, and define minimum cost constraints as follows: “Maximum Number of Sections” = 1, “Minimum Section Length” = 1,000 ft. Select the Design tab on the dialog box, and then apply the following design envelope criteria.


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Click OK to apply the changes and close the dialog box.

Enter 1 as the Maximum Number of Sections. Enter 1000 ft as the Minimum Section Length.

Select the Design tab, and then apply the design envelope criteria as shown.

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While in Template mode, check the contents of the Wellbore and Tubular menus. Grayed out menu commands, and Well specific data (for example, Geothermal Gradient and Production Data), are not accessible in Template mode.

Grayed out menu commands are not available in Template mode.


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Select the Work tab, and then select View > Well Schematic.

e) Select File > Template > Save As. Enter My Template in the Template Name field, and then click OK. Enter My Template as the new template name.

Notice the recently created template was added as a “User Defined Template” in the Well Explorer.

The newly created template now exists in the Well Explorer tree under the “User Defined Templates” node.

Select File > Close to close the template.

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f) Select File > New > Instant Design, accept the defaults, and then click OK to create an instant Design.

When the Open Template dialog box appears, select My Template as the template to apply to the Design. Click OK to apply the template to the instant Design.

Observe that the newly created Design with “My Template” applied includes all changes that you made in template. •

By default, the new Design displays both the currently displayed Work tab and the Well Schematic tab.


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•

Select Tubular > Pipe Inventory. The pipe inventory includes the 9 7/8” casing created in “My Template”.

•

Select Wellbore > General, and then enter a well depth MD. For example, enter 10,000 ft.

Select Wellbore > Casing and Tubing Scheme, and enter a “Production” casing string.

Select Tubular > Design Parameters > Design Factors tab, Tubular > Burst Loads, Tubular > Collapse Loads, Tubular > Axial Loads, and Tubular > Minimum Cost.

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Notice that all changes made in “My Template” are assigned to the current instant Design. The example below shows the burst safety factor of 1.2 entered previously in “My Template”.


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StressCheck - 5000.1.13

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