B01 ÔÇô Saphir Guided Interpretation #1 Basic Features

Installation and Learning Guide

Saphir guided interpretation #1 • B01-1

Saphir V.3.0 - © KAPPA Engineering 1994-2001

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B01 – Saphir guided interpretation #1: Basic features

This chapter is an introduction to the basic features offered by Saphir. This first interpretation can be followed in all levels of Saphir except Saphir Reader.

B01.1 • Before starting Saphir To follow this guided interpretation, you should have: • •

Saphir installed on your system. The files Sapb01.rat and Sapb01.asc, which by default are copied during installation to your hard disk, and should be located in the program example directory.

B01.2 • Starting a Saphir session In the File menu of the Saphir main screen choose “New”, the initialization main options dialog box is opened:

Fig B01.1 Initialization main options dialog box This screen allows the following inputs: •

Test type (Standard, Interference)

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Fluid type (Oil, Gas, Water, Condensate, Multiphase)

The reference date and time to calculate the elapsed time from data vs date/time of day (TOD) files. The user can have access to the “units” dialog by clicking

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Fig B01.2 Initialization Units dialog box The default units at installation are Oil Field. Alternative units can be chosen by clicking on the “Load” button (SI or Hydro systems). The system of units can be customised by selecting the desired unit for each parameter. The “Other Units” are Emeraude units not used by Saphir, but a single common system of units can be shared between the two applications. A customised units file can be saved and reloaded whenever whenever required. Click “OK” to accept the default units. Click on

to input the test information in the table:

Fig B01.3 Initialization Information dialog box Note: Additional information can be input by clicking “Add”. Click “OK”. Click on to enter the PVT fluid parameters value:










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Fig B01.4 Fluid PVT parameters dialog This dialog allows the input of PVT parameters when available. If PVT parameters are not available, clicking on accesses the Kappa PVT facility. Accept the default values by clicking OK. Click on

to input the formation parameters:

Fig B01.5 Initialization Parameters dialog box Note: the parameters can be input in different units, the available units are given in the pop-up menu on the right hand side. Click on “Create” to accept these default parameter values and to access to the “interpretation” control panel page. Save the current file as “Sapb01” with the “Save” option in the “File” menu, in the sub-directory “example” under your installation directory.










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B01.3 • Saphir Main Screen The Saphir main screen, Fig. B01.6, consists of: •

TM

A control panel similar to Microsoft Outlook on the left of the screen. The first page to appear is ”Interpretation”. Options not available at this stage are greyed out. The next logical default option is highlighted by a red frame.

•

The menu bar at the top of the screen gives access to standard Windows facilities.

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The toolbars.

•

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The screen pages corresponding to various aspects of the analysis; QA/QC, Edit Data, Edit Rate, 2-D Map and Analysis, can be selected by clicking on the relevant tab. Process messages are displayed at the bottom of the screen.

Fig B01.6 Saphir main screen; Interpretation panel










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B01.4 • Loading a rate history file As no file has been loaded at this stage, the only only options enabled in in the control panel are Load Q (rates) and Load P (pressures). The default, framed in red, is to load the rates. Click on

to load the rate. The first dialog asks for the origin of the data.

Fig B01.7 Origin of the data Keep “Ascii file” as the input origin, and click OK. Select the file Sapb01.rat with the browser, the load dialog is displayed:

Fig. B01.8 Load Rate Dialog The main options in the load dialog are: •

Type of rate information: surface (default) or downhole.

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Type of time information: duration (default) or time at start.

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Definition of time shift.

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Re-selection of the input file.

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Definition of the file format.

The format can be defined as “field” (series of characters separated by tab, spaces or user defined), or










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B01.5 • Loading a pressure history file The rate history is now displayed in a new plot and the control panel the default option is now on “Load P”:

Fig B01.9 Main screen after rate load Click on

and the next dialog box asks for the origin of the data.

Fig. B01.10 Data origin dialog Keep “Ascii file” as the input origin and click ‘OK’ to confirm; select the file Sapb01.asc with the browser. The load dialog is displayed:












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Fig B01.11 Load pressure dialog The program suggests loading the file Sapb01.asc in free format with no time shift, no window (i.e. no limit in the time and pressure ranges) and no filter. These items are illustrated in the second guided interpretation and in the relevant pages of the Reference Manual. Click on to load the pressure history using the default settings. The pressures are now displayed on the history plot:










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B01.6 • Extracting a group In the control panel the “Load dP” option is now enabled and suggested as default: i.e. select pressure data from a group where the diagnostic will be performed. Click on

to call the “Extract dP” dialog:

Fig B01.13 Load Delta P dialog Saphir is not restricted to loading DeltaP for a single constant rate and an analysis can be made on a “group” of rates. By default, when the rate history is loaded, Saphir creates groups that can be: •

A production group: A sequence of flow periods of strictly positive rates.

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An injection group: A sequence of flow periods of strictly negative rates

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A build-up: A zero rate period after a production

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A fall-off: A zero rate period after an injection

The dialog Fig B01.13 allows the selection of the gauge (in this example there is only one) and the group (build-up #1 or production #1). Click on ‘OK’ to confirm the choice. The Delta P load parameters dialog is displayed:










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A log-log plot of the pressure change and the derivative derivative is displayed at the same time as a semi-log plot of pressure change against superposition time and the job history plot, Fig. B01.15. These "Automatic" plots are always displayed after a group has been extracted. Their scales may be changed but they cannot be deleted, as they are necessary for the rest of the interpretation process. The match lines have been drawn on the log-log plot, the pressure match is set where the derivative starts to stabilize and the 45° line for the time match has been set on the early time (wellbore storage) data. The default option on the control panel is now ‘Model’.

Fig B01.15 Main screen after loading deltaP It can be seen that at early time, the derivative follows a unit slope, but with a difference between the pressure and its derivative, which is likely to come from a wrong estimation of the initial pressure. The difference is 3 psi out of a total pressure change of several hundred psi. The true value of p@dt=0 should be 3087 psia. We shall override the default option and correct deltaP to get a better pressure curve.

B01.7 • Active plot options










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B01.7.1 • Correcting a flow period Click on the right mouse button in the log-log plot area and select “Set” and P@dt=0 P@dt=0 in in the pop-up menu. The following dialog is displayed:

Fig B01.16 Input the correct last flowing pressure: 3087 psia. Click OK. The early time data are now corrected in the log-log plot and we are ready to proceed with the analysis:

Fig B01.17 Log-Log after correction










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Fig B01.18 IARF straight line The semi-log straight line can also be drawn with the same procedure on the superposition plot. Clicking on the right mouse button on the maximized log-log or the semi-log plot, then on results or the results button in the toolbar shows the results corresponding to the straight line. Results can also be accessed by double clicking in the small “status” window at the top right of the screen.

B01.8 • The file menu This is a good time to save the file and see how it is stored: Click on to save the interpretation at this stage. File menu: The available options, detailed in the reference manual are: •

New

To start a new interpretation

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Open

To open a previous interpretation

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Close

To close the current interpretation but remain in Saphir









Installation and Learning Guide Saphir V.3.0 - © KAPPA Engineering 1994-2001

Saphir guided interpretation #1 • B01-12 Doc V3.00.12

B01.9 • Model generation The “Model” option is now the default on the control panel. Clicking on “Shift” causes a “flash” sign to appear on the interpretation page icons of the control panel. This calls the “automatic” equivalent of this option. Click on to generate the automatic model. The automatic model assumes an homogeneous infinite behaviour. The kh and C being calculated from the current pressure and time matches, Saphir estimates a value of skin coherent with the pressure change and generates the model. Using this model and the flow-rate history, the program then back calculates the initial pressure Pi from p@dt = 0. The multirate model is generated and displayed with the data for comparison on the Log-log, Semi-log and History plots, Fig. B01.21.







Installation and Learning Guide Saphir V.3.0 - © KAPPA Engineering 1994-2001

Saphir guided interpretation #1 • B01-13 Doc V3.00.12

Since the automatic model has been generated, Saphir is holding a value for the Skin factor and the ‘Generate’ option is enabled. The model dialog box is presented as a spreadsheet. Each parameter value can be edited in the corresponding box. Three drop boxes select the desired model by determining the well conditions, the reservoir type and the boundaries. On the right hand side, boxes can be checked to enable special model conditions such as rate dependent skin and changing wellbore storage. The Pi value can be specified and imposed instead of using the back simulated value from the model. In case of a multiwell configuration the user can add the interference from other wells. On the bottom left the button opens a dialog whereby the user can extend or shorten the simulation calculation.

B01.10 • Matching the model to the data Activate the log-log plot by double clicking on the header. Click on the right mouse button and in the pop-up menu select “results” to see simultaneously a short version of the results and the facilities of the active plot. To modify the match, click on the plot holding the mouse button down. The model can then be dragged across the screen to the best fit with the data. The results calculated from the match are simultaneously updated.










Click on

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to call the improve option. By default all parameters are set as variable, Fig B01.22.

Fig. B01.22 Improve dialog box The parameters are selected constant or variable in the regression by setting the corresponding check box. Clicking on

will call the following dialog:










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Fig B01.24 Regression progress dialog Double click on the plot header to return to the main screen.

B01.12 • Horner plot Since this test was a build-up following a single production period a Horner plot is a valid alternative to the superposition plot. In the Control panel select the page Interpretation 2”. Click on the icon

to access the flexible plot facility:










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Fig B01.26 Horner and derivative plot Note: When exiting this Saphir session save the Sapex01 file to use it later in another guided session. What next? •

Restart the same interpretation from nothing without using this documentation.

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Try the same facilities on a set of data of your own.

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Go to the second guided interpretation, to use more control panel functions and additional options. The second guided interpretation assumes that you are familiar with the basic facilities described in this first

B01 ÔÇô Saphir Guided Interpretation #1 Basic Features

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