OFM 2005.1 Forecast Analysis Fundamentals

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OilField Manager Forecast Analysis FundamentalsTraining and Exercise Guide Version 2005.1 Schlumberger Information Solutions May 16, 2005 Copyright Notice © 2005 Schlumberger. All rights reserved. No part of this manual may be reproduced, stored in a retrieval system, or translated in any form or by any means, electronic or mechanical, including photocopying and recording, without the prior written permission of Schlumberger Information Solutions, 5599 San Felipe, Suite 1700, Houston, TX 77056-2722. Disclaimer Use of this product is governed by the License Agreement. Schlumberger makes no warranties, express, implied, or statutory, with respect to the product described herein and disclaims without limitation any warranties of merchantability or fitness for a particular purpose. Schlumberger reserves the right to revise the information in this manual at any time without notice. Trademark Information GeoFrame™, StratLog™, WellPix™, WellEdit™, WellSketch™, and CPS3™ are trademarks of Schlumberger. Certain other products and product names are trademarks or registered trademarks of their respective companies or organizations. Schlumberger Private Creating a Forecast Analysis Schlumberger Table of Contents Chapter 1 Creating Forecast Analysis ............................................................ 2 Learning Objectives ............................................................................................................ 2 Setting Up a Forecast Scenario ......................................................................................... 3 Editing the Graph ................................................................................................................ 7 Working with Different Forecasting Features................................................................... 14 Hyperbolic Fit Type ................................................................................................... 17 Exponential Fit Type.................................................................................................. 23 Add Schedule ............................................................................................................ 25 Exponential Fit Type.................................................................................................. 27 Manual Match for Empirical Solutions.............................................................................. 41 Chapter 2 Forecast.......................................................................................... 44 Using the Output Features ............................................................................................... 44 Working with Cases .......................................................................................................... 47 Auto Decline...................................................................................................................... 49 Chapter 3 Additional Forecasts ..................................................................... 51 Water Cut versus Cum.Oil Analysis ................................................................................. 51 P/Z vs. Cum.Gas Analysis................................................................................................ 55 Chapter 4 Fetkovich Type Curve Analysis ................................................... 64 Using Fetkovich Type Curve Analysis (Late-Time) ......................................................... 65 Chapter 5 Analytical Transient Solutions..................................................... 75 Using Analytical Transient Solutions................................................................................ 75 Chapter 6 Retrieving Forecast Results......................................................... 85 Calculated Variables ......................................................................................................... 85 OFM Forecast Analysis Fundamentals May 16, 2005 1 the forecast result will be slightly different than that of grouped individual well forecasts (i. the Forecast module in OFM has been enhanced to facilitate more sophisticated analyses. you will focus on using the Empirical method of forecasting. Forecasts can be done on single well (completion) level. q=C(Pws^2 . time. If you choose to perform the forecast on a group of wells. and Analytical Transient solutions. OFM will initially plot control points based on historical or digitized data regression. Locke & Sawyer and Analytical Transient Solution techniques are type-curve analyses. The Well Deliverability Analysis enables you to analyze data from FlowAfter-Flow tests (Back Pressure Analyses). Interactive manual match techniques for empirical solutions are introduced in this version of OFM. “group of the forecasts”. Empirical. cum. Locke & Sawyer. summing the individual forecasts). There is a session covering the basics of Fetkovich and Analytical Transient methods.Pwf ^2) ^n. Fetkovich. More in-depth coverage of the type curve-based methods will be addressed in more advanced OFM training courses. In OFM 2005. or on a group of wells. All the terms used in this module have been documented to give users more comprehensive information. rate vs. Formerly known as Decline Curve Analysis (DCA). Fetkovich. manual match method is automatically activated and the user will have total control of how the match should be performed. you will be introduced to the fundamentals of creating forecast analysis. In this lesson. This is the issue of “forecast of a group” vs. OFM allows you to perform more advanced techniques such as ratios and cuts vs. 2005 . the Forecast module consists of four major categories (techniques).Creating a Forecast Analysis Schlumberger Chapter 1 Creating Forecast Analysis Welcome to Introduction to Forecast Analysis in OilField Manager (OFM)! In this course you will learn how to use empirical and analytical techniques to forecast production and retrieve forecast information for further studies. category level. and Modified Isochronal Tests using the following empirical equation. Isochronal Tests.e. The online Help file has been updated for the Forecast module. You will successfully learn how to perform the following procedures within this workflow: • • Set up a forecast scenario Use different forecast features 2 OFM Forecast Analysis Fundamentals May 16. In addition to basic forecasts like rate vs. Once a control point is moved. which require better understanding of the reservoir model as well as the parameters controlling the well/entity behavior. Schlumberger Private Learning Objectives In this section. cum. 4.Oil > 50) & (Date >= 19980101). Click OK to save the query. The definition of the query is (Monthlyprod. Note: If you do not have the well list or the query file. It should resemble the image below. We are going to use the active producer after 1998. the criteria is met 3 times. and the Consecutively box checked. 3. about half of the wells are not productive and approximately 80% of the other half has already stopped producing. OFM Forecast Analysis Fundamentals May 16.Creating a Forecast Analysis Schlumberger Setting Up a Forecast Scenario In the Demo2005 database. Select Prod_Wells98. 2005 3 . right-click and select Open. select the Well List node. select the newly created filter to apply the conditions to the basemap. please take some time to set up the query to do it. 2. From the Filter pane. From the Filter pane. The Well List dialog displays. 1.txt and click Open. 9.Creating a Forecast Analysis Schlumberger 5. OFM Forecast Analysis Fundamentals May 16. Select Analysis>Forecast. Click to Group all the wells. The forecast tabbed page is displayed in the OFM main window. Schlumberger Private 7. The Edit Scenario dialog displays. 8. The Scenario Manager dialog displays. Select Oil from the Phase/Analysis list field. 2005 4 . Highlight the DefaultScenario from the Scenarios list and click Edit. Select Edit>Scenario Manager. 6. Water Cut. Reselect the Oil phase. 11. 14. the Oil Rate variable is Oil. For this phase (Oil). 12. Select the Historical Regression tab.Oil variable should be Oil. Select Best Method from the Method section of the dialog. WOR.Cum (a monthly frequency variable). 13. OFM Forecast Analysis Fundamentals May 16. and Oil Cut) and set them up accordingly. The Cum. Go through all other phases (Gas and Water) and Ratios (GOR.Creating a Forecast Analysis Schlumberger 10. 2005 5 . the Time (Date) variable should be Date. We will work on the Oil phase and use the Empirical method.CalDay. 16.Creating a Forecast Analysis Schlumberger 15. set for 60 months (5 years) Schlumberger Private End Rate. specify the following: • • • • • • Start Time – Months from End. Decline Type – Historical Regression OFM Forecast Analysis Fundamentals May 16. 2005 6 . Select the Forecast tab. You are defaulted to Schedule 1. Enter 1 as the end limit. In that schedule. starting at 0 (zero) month Start Rate – Last Historical Rate Reserve Type – Proven-Developed End Time – Months from Start. Select Edit>Graph or right-click on the graph and select the Graph option from the menu. it is time to work on the appearance of the graph. OFM Forecast Analysis Fundamentals May 16. 2005 7 .Creating a Forecast Analysis Schlumberger Note: The Forecast tab has lots of options. 17. The Edit Plot dialog in Forecast module is similar to the Edit Plot dialog in Plot module. Please read the online help to understand the usage of those available options (for example. Editing the Graph 1. when to use Last Historical Rate. Click OK. and when to use From Historical). Now that the forecast scenario is set. Control Points . Working points then have different attributes to distinguish with excluded points. you can select to exclude data points (that you do not think are reliable). This database forecast result can be retrieved from other modules in this project. Historical . so they do not affect your result. 2005 8 . This action enables a browse button.Forecasting is an ongoing process. Click in the field to the right of Result Items.In this module. Schlumberger Private • • • • 2. Working forecast results can only be seen in the Forecast module.Attributes of the fitted line. OFM Forecast Analysis Fundamentals May 16.Creating a Forecast Analysis Schlumberger Notes: • Database Forecast .Attributes of the diagnostic variable data (historical data).Once you like your forecast result. your forecast is still a “working forecast”. 3. Locate the Legend section of the Properties pane. not anywhere else in the project. you can save it to the database. Fitted Curve . Control Points are the end and middle points used for the manual match. As long as you have not saved your forecast result yet. Working Forecast . Locate the Graph Settings section of the Properties pane. 2005 9 . OFM Forecast Analysis Fundamentals May 16. Click in the field to the right of Setup. This action enables a browse button. 7. Clear the checkbox of the parameters you do not want to display and click OK. 5. 6. Click the button to display the Result Legend Items dialog and select the result items to display.Creating a Forecast Analysis Schlumberger 4. 11. OFM Forecast Analysis Fundamentals May 16. Click this button to open the Headers dialog. Schlumberger Private 9. 10. Click OK. The definition is @fmtdate( @today(). Add another header that reports today’s date. 2005 10 . "mm/dd/yyyy").Creating a Forecast Analysis Schlumberger 8. Your Headers dialog should resemble the image pictured below. Click Assist and enter "Forecast: "+@name(). 12. Click Add. Move and edit the Header/Label Fonts. • 14. or highlight the item to move then select Move from the right mouse click menu.Creating a Forecast Analysis Schlumberger 13. Click OK. To move/resize graph. Select Edit>Limits>Lower. OFM Forecast Analysis Fundamentals May 16. move the legend to get an output similar to the one pictured below. To edit the headers. resize the graph. The Legend/Axis Label Fonts can be edited from the right mouse click>Font menu. 2005 11 . The graph displays. use the left mouse button in a “drag and drop” operation. To move Legend and/or Axis Label. The Label can also be modified via from the right mouse click>Edit menu. use the left mouse button to “drag and drop”. Notes: • • • • To move a header. select Edit>Graph>Headers. click the right mouse on the graph and select Graph Move/Size. When the action is complete.Creating a Forecast Analysis Schlumberger 15. 17. Click to draw the line under the last declining portion of the historical curve as shown. 2005 12 . Schlumberger Private Notes: • • When applying the Lower Limit line. the right mouse click gives you the options to complete or undo (last or all) the operation. any data points below and out of the line are excluded. When drawing the line. OFM Forecast Analysis Fundamentals May 16. Select File>Case (or click the Save button). Case1. 16. to save to the current case. right-click and select Done from the shortcut menu. You can edit the group name now for future use if you wish. If you do not suppress warning messages. 2005 13 . OFM will provide a message to remind you that you have to regroup before the saved forecasts can be viewed in other modules.Creating a Forecast Analysis Schlumberger Note: (Optional) You can save to another case using Save to Different Case by select File>Save to Different Case. OFM Forecast Analysis Fundamentals May 16. Select Edit>Scenario. 2005 14 . Place a lower limit on the data as shown to exclude the first and the last two data points. click the Forecast tab and select Last Fit Rate from the Start Rate list. The BLUE_1:Ge_6 well displays. Right-click and select Done when finished.Creating a Forecast Analysis Schlumberger Working with Different Forecasting Features 1. OFM Forecast Analysis Fundamentals May 16. which may not be very good with insufficient historical data and with the last historical rate excluded. Click Next. 4. Schlumberger Private Our starting rate is set at Last Historical Rate. Locate the Step toolbar at the top of the OFM main window. 2. 3. 6. However. Click Next. 2005 15 . The forecast for BLUE_1:He_0 displays (based on the default case). 7. Right-click and select Done. the best fit should be hyperbolic. Note: that the best-fit case for historical regression is Exponential.Creating a Forecast Analysis Schlumberger 5. Place the lower limit as shown. excluding the first few data points that are not representative of the well’s decline behavior. Click OK. Save the forecast (from File>Save or using the Save button) and the graph displays. OFM Forecast Analysis Fundamentals May 16. 8. 10. Select the Forecast tab. 9. Click OK. we may want to start forecasting from the last historical date of the well. OFM Forecast Analysis Fundamentals May 16. 2005 16 . Click Next.Creating a Forecast Analysis Schlumberger Note: The start time is at the last date of the project. Schlumberger Private 11. Save the forecast. and select Last Historical Date from the Start Time list. Select Edit>Scenario. In this case. The graph displays. The working forecast for BLUE_5:Sc_0 displays. Set the b Value Method to User. Place a lower limit (and upper limit if needed) to rule out the anomalous data points (noise). Hyperbolic Fit Type 1. 2. 3. Set the User value to 0. OFM Forecast Analysis Fundamentals May 16. Locate the Historical Match section of the Properties pane. OFM will select the best b-value to use Hyperbolic regression). Set the Fit Type to Hyperbolic. 12.Creating a Forecast Analysis Schlumberger Even though it appears to be a good fit. and the forecast looks acceptable. 2005 17 . 4.6 (if you do not enter your own b-value. for example at the beginning of the production history. there are things that we can do to obtain a better result. Schlumberger Private 7. Note: In the Decline Parameters Type list box. You can also select the Hyperbolic in the Decline Type list box. and then enter the value of 0. Click OK. 6. Click Next. 2005 18 . The result should be similar if you enter a value for decline rate that is close to the default (calculated) decline case. From the Start Rate list. the Historical Regression option is selected. It means that the forecast will be the continuation of the historical hyperbolic regression. select From Fit. OFM Forecast Analysis Fundamentals May 16. Select Edit>Scenario and click on the Forecast tab.6 for the “b-value”.Creating a Forecast Analysis Schlumberger 5. 8. The forecast for GREEN_4:Ad_3BU displays. Still we can reasonably perform the forecast on this well. Thus there is no default forecast on this well. 9. 2005 19 . Select the Forecast tab.01 for Decline Rate. OFM Forecast Analysis Fundamentals May 16. Select Last Historical Date for Start Time. 13. 14. Select Edit>Scenario. From the Decline Parameters Rate list field select User Defined and enter 0. Select From Fit for Start Rate. 12. From the Decline Parameters Type list field select Exponential. Place a lower limit as shown in the image below. 10.Creating a Forecast Analysis Schlumberger Note that the last historical rate is already below the economic limit. 11. 15. 2005 20 . 17. Click OK. The forecast for GREEN_6:Li_1C displays. OFM Forecast Analysis Fundamentals May 16. Click Next.Creating a Forecast Analysis Schlumberger Schlumberger Private 16. Set the Minimum and Maximum values to 0. Set the b Value Method to Range. Place an upper limit as shown in the image below. 20. 2005 21 . modify the following settings from the History Match section. Set the Fit Type value to Hyperbolic. OFM Forecast Analysis Fundamentals May 16. respectively. 19.6. 22. 21.3 and 0. From the Properties pane.Creating a Forecast Analysis Schlumberger 18. Place a lower limit as shown in the image below.Creating a Forecast Analysis Schlumberger 23. OFM Forecast Analysis Fundamentals May 16. 2005 22 . Schlumberger Private 24. Click Next. The forecast for ORANGE_18:De_3 displays. Click OK. Select Edit>Scenarios.Creating a Forecast Analysis Schlumberger 25. Click Next. 8. 2005 23 . The forecast for ORANGE_19:Ad_1A displays. OFM Forecast Analysis Fundamentals May 16. Select Last Fit Rate for Start Rate. From the Properties pane change the Fit Type to Exponential. Save the forecast. Select Last Historical Date for Start Time. Exponential Fit Type 1. Place an upper limit as shown in the image below. 2. 3. 6. 7. 5. 4. Select the Forecast tab. 9.03 in the adjoining field. a work over was successfully completed with significant increase in production afterwards. Select Edit>Scenario. End Time . The decline trend after work over has been different from the common trend. 13. Enter “30” (months) in the adjoining field. Enter “0” in the adjoining field.1. early 1996. As seen.Creating a Forecast Analysis Schlumberger This well has a good history of production. Set the lower limit as shown in the image below. Further studies of this completion indicate that the well would follow this current trend for a short period and then return to the historical best-fit trend. End Rate . Start Rate . Schlumberger Private OFM Forecast Analysis Fundamentals May 16. 12. Set the upper limit to exclude the points that constitute the spike in late 1995. Somewhere in 1996.Last Historical Rate.Exponential. 10. 11.User Defined and 0.Months from End. Specify the following: • • • • • • Start Time . Select the Forecast tab. the decline trend from 1984 to 1994 could be identified as the common trend of the well. Rate . 2005 24 .Months from Start. Decline Parameter Type . This will be a case to apply a multiple schedule forecast. End Rate .Historical Regression. Enter “30” in the adjoining field. 2. Start Rate .Months from End.Previous. 2005 25 .1.Months from Start. Click Add to add Schedule #2. OFM Forecast Analysis Fundamentals May 16. Specify the following: • • • • • Start Time . End Time . Decline Type . Enter “0” in the adjoining field.Creating a Forecast Analysis Schlumberger Add Schedule 1. Click Next. The forecast for ORANGE_23:Li_1C displays.Creating a Forecast Analysis Schlumberger Schlumberger Private 3. 4. OFM Forecast Analysis Fundamentals May 16. 2005 26 . Click OK. set the Fit Type to Exponential. no default forecast can be carried out. 4. Click Next. 7. However. 2005 27 . Select Last Fit Rate from the Start Rate list. The graph for ORANGE_26:Cl_3 displays. 2. Select Edit>Scenario. Save the forecast. The production (decline) trend of this well is easily identified. Select the Forecast tab. The trend from mid-1994 to the last historical date could well determine the well’s behavior for forecasting. 6. OFM Forecast Analysis Fundamentals May 16. the forecast will be stopped before the end of the forecast period due to the forecast rate reaching economic limit first. For this well. Therefore. From the Properties pane.Creating a Forecast Analysis Schlumberger Exercise 1 Create a Forecast Using what you have learned. 3. Set the lower limit to exclude the first and the last production data points as desired. 5. the last historical rate is below the economic limit. do the forecast for this well. Exponential Fit Type 1. Click OK. OFM Forecast Analysis Fundamentals May 16. OFM will use hyperbolic regression in this case. 2005 28 . 10. The forecast for ORANGE_31:De_1 displays. Schlumberger Private 9. That means the specified End Rate is met before the forecast End Time. Take a look at the legend.Creating a Forecast Analysis Schlumberger 8. The Forecast Ended By field reads “Rate”. Still the forecast will stop before it reaches the time limit. Save the forecast. (Optional) If you select Best Fit from the Method choices. Click Next. OFM Forecast Analysis Fundamentals May 16. and the decline trend for this well should follow this trend instead of the overall trend that takes into account data points from previous production periods.Creating a Forecast Analysis Schlumberger This well has produced consistently throughout its production history. Click OK. Somewhere in the second half of 1997. Select Edit>Scenario. 14. Set the lower limit as shown in the image below. 13. the well experienced an increase in production. Select the Forecast tab and enter 150 (to verify the well reaches economic limit before the time limit) in the adjoining field of Ending Time>Months from Start. 12. 2005 29 . 11. In the Decline Parameters Rate field select Calculate from Reserves and Schedule Time. Select the Forecast tab. We can schedule reserve (or specify total reserve) and ask OFM to adjust decline rate to reserve. The graph displays. 22. 2005 30 . Edit the Scenario again. In the Schedule Reserves field enter 40.Creating a Forecast Analysis Schlumberger Save the forecast. 18. The Forecast Ended By field is Rate. The forecast displays. separate analyses suggest that the well has about 40 Mbbl in remaining reserve. 17. Schlumberger Private 20. OFM Forecast Analysis Fundamentals May 16. Click OK. In the Total Reserves field enter 355. The value of EUR is about 347 Mbbl. The remaining reserve is about 31 Mbbl. 21. Click OK and do not forget to read the legend to verify the results. However. Read the legend. or about 355 Mbbl in total reserve. 19. Clear the Schedule Reserves list field. 15. Select Edit>Scenario. 16. there is a period of anomaly (from mid-98 to mid-99) that needs to be reckoned for. Set the lower limit to take into account the production period from mid-95 to mid-98. 24. 2005 31 . Save the forecast. The behavior from mid-95 to mid-98.Creating a Forecast Analysis Schlumberger 23. 25. The forecast for ORANGE_32:Li_1C displays. Click Next. and the one from mid-99 on could well be the trend for our forecast. OFM Forecast Analysis Fundamentals May 16. Study the production history of this well. However. Select the Forecast tab. and enter 84 (including 2 years from mid-98 to the last historical date). Schlumberger Private OFM Forecast Analysis Fundamentals May 16. 30. Select Edit>Scenario. 27. 29. select Date.Creating a Forecast Analysis Schlumberger 26. 31. Select Reserve Type of Possible. Set the Start Rate list to From Fit. Select Months from Start from the End Time list. and then enter 19980630 in the adjoining field. From the Start Time list. 2005 32 . 28. You are returned to the Scenario Manager. OFM Forecast Analysis Fundamentals May 16. 35. Click OK.Creating a Forecast Analysis Schlumberger 32. The forecast for ORANGE_34:Ad_1A displays. 2005 33 . The graph displays. Click Close. Click Next. 33. Save the forecast. 34. The limited data for this completion shows a sharp drop in production. Select Edit>Scenario.05 M. select Date and enter 20001031 in the adjoining field.Creating a Forecast Analysis Schlumberger ORANGE_34:Ad_1A has short historical production data. 2. which is a fairly good shut-in rate.). 2005 34 . 1. Select the Forecast tab. However. It has been suggested that this well may be put on production for a short period of time and be shut in to perform corrective measures and then put back on production following the partially fitted trend (Decline Rate of about 0.e. The End Rate and Reserve Type are of insignificance in this example. From the Properties pane. the last data point does not follow the generic trend. We can see that the well will have about four more months before reaching10 bbls/d. All these operations/parameters can be reflected in your forecast estimation. and it could be incorrect if we decide to use the overall best fit (dictated by the first five data points) or the partial fit through the last two data points. set the Fit Type to Hyperbolic. Schlumberger Private OFM Forecast Analysis Fundamentals May 16. From the End Time drop-down list. which may indicate this is a troubled well. 4. using multiple-schedule forecast technique. 3. Creating a Forecast Analysis Schlumberger 5. 7. and enter 6 (months) in the adjoining field. Click Add. 6. Schedule #2 displays. 2005 35 . check the Days Off options and enter 31 (days) in the adjoining field. In the Oil Advanced Settings group box. From the End Time drop-down list. OFM Forecast Analysis Fundamentals May 16. verify Months from Start is selected. From the Start Rate list. 2005 36 .) in the adjoining field. OFM Forecast Analysis Fundamentals May 16.05 (M. from the Type list field select Exponential.e. 13. Add Schedule #3. select Change By Percent and enter 300 (%) in the adjoining field. In the Decline Parameters section of the dialog.Creating a Forecast Analysis Schlumberger Schlumberger Private 8. In Oil Advanced Settings. Select Unproven for Reserve Type. 12. From the End Time list. 11. In the End Rate field enter 1 (bbl/d) as the desired limit. 10. check Shut In Effect and enter 300 (%) in the adjoining field. In the Decline Parameters Rate field select User Defined and enter 0. verify Months from Start is selected and enter 50 (months) in the adjoining field. 9. Click OK. OFM Forecast Analysis Fundamentals May 16.Creating a Forecast Analysis Schlumberger 14. 2005 37 . Exercise 2 Shut in activities Experiment other ways to simulate shut in activities in this well. Studies show that this well has all the same parameters as a nearby well. which we know the trend. The best-fit line is redrawn. Right-click on the graph and select Digitize Points (or select Edit>Digitize Points). A different approach must be used to estimate the forecast for this well.Creating a Forecast Analysis Schlumberger 15. The forecast for ORANGE_34:Ad_3BU displays. When finished. Therefore. 2005 38 . review the magenta points selected on the graph . This well has a very short and erratic production history. Schlumberger Private 18. 17. it is nearly impossible to determine a trend of any kind. right-click and select Done. OFM Forecast Analysis Fundamentals May 16.you may want to zoom in from the View menu). 16. Click Next. Reset the zoom on the graph if needed. Click the points where you believe the best-fit line should be (For your reference. The graph is redisplayed. The forecast for ORANGE_34:Li_1C displays. 22. Select the Forecast tab. 24. Click OK.Creating a Forecast Analysis Schlumberger 19. You may want to rule out data points before the peak production (early time) to obtain a better fit. Select Last Historical Date from Start Time drop-down list and From Fit from Start Rate list. The best-fit line should then be hyperbolic. Click Next. Set a lower limit to rule out the first five data points. Select Edit>Scenario. 23. 2005 39 . 20. Save the forecast. 21. 25. The well has excellent production trend but ask yourself why there are no production data after August 1999. OFM Forecast Analysis Fundamentals May 16. This looks like a very reasonable forecast. 2005 40 . and there might have been a work over near the end of 1986. Study those three wells and perform the forecasts for them. which really revitalized its production. ORANGE_35:Ad_1A. 26. RED_4:Cl_3 (you can do it from the drop-down well list).Creating a Forecast Analysis Schlumberger The next three wells. ORANGE_35:Ad_3BU. Select the last well from the filter list. 27. Set the lower limit and upper limit so the used points are as shown: OFM Forecast Analysis Fundamentals May 16. Thus the trend should be determined from that time on. Do not forget to save your forecasts when done. and ORANGE_36:Li_1C all have very brief and erratic production history. Schlumberger Private This well has good history. e. manual match method is automatically activated and the user will have total control of how the match should be performed. OFM Forecast performs historical regression automatically by default when using empirical solutions.Creating a Forecast Analysis Schlumberger 28. constraints to the movement of the control points). if the fit type is set to exponential you cannot move the control points to make a hyperbolic regression line. how do we view the forecast results? Manual Match for Empirical Solutions OFM will initially plot control points based on historical or digitized data regression. save it. Select Blue_5:Sc_0 from the Step pane. Question Now that we have done the forecasts on the selected wells. Once a control point is moved. OFM Forecast Analysis Fundamentals May 16. Note: There are constraints in the manual matching algorithm (i. Users have the ability to interactively adjust the regression parameters by using the mouse to change the shape and position of the fit curves. The manual match mode remains active until the match method is changed to Auto in the Properties pane. Once you are satisfied with this forecast. 2005 41 . 1. For example. In the example shown there are three control points. The number of control points are determined by the decline type (or the relationship between dependent and independent variables) and the number of to-be-determined parameters. Select a control point and then drag it. There are three data points (in blue color) on the historical fit curve. The control points are initially calculated using the equation obtained from auto match. To view Historical Regression results. OFM Forecast Analysis Fundamentals May 16. On the Historical Regression results pane you can see that the best fit for the historical data is hyperbolic decline with an R-squared (R^2) value of 0. These points are Control Points. Schlumberger Private 3.Creating a Forecast Analysis Schlumberger 2.902190. b value and initial decline rate (Di). which are used to determine initial flow rate (qi). which control the shape and position of the fit curve during manual match process. 2005 42 . click the Historical Regression tab located at the base of the Forecast window. 2005 43 . b. and their position to the X. Note the match method property on the property pane is now set to Manual. and Di) are calculated instantaneously based on the control points. This will only result in moving the control point.Creating a Forecast Analysis Schlumberger Note: You can also move the fit curve selecting it and dragging it. OFM Forecast Analysis Fundamentals May 16. During manual match process the parameters (qi. If you want to move the curve do not position the mouse over the control point.and Yaxis as you dragging and moving them. Viewing the Forecast Schlumberger Chapter 2 Forecast Even though you can generate forecast from monthly, daily, or even sporadic data, the forecast (rate) results in OFM are stored in monthly frequency. By default, OFM activates four report tabs, Historical Regression Report, Forecast Report, Summary Report, and Database Forecast Report. You can close any of these tabs from the View menu as desired or by selecting the tabbed page and clicking the Close button. Learning Objectives In this section, you will be introduced to viewing the forecast. You will successfully learn how to perform the following procedures within this workflow: • • Create and compare cases Use the auto decline feature Using the Output Features Note: The next steps assume that you are on the last well, RED_4:Cl_3, and have saved its forecast results to the database. 1. Select the Historical Regression tab and the following displays. OFM Forecast Analysis Fundamentals May 16, 2005 44 Viewing the Forecast and Output Window Features Schlumberger This tabbed page enables you to read the information about your (real) historical data and the fitted data, the fit equation, and its correlation coefficient. Note: To anchor the window, click the push-pin in the upper right corner. The vertical push-pin indicates that the auto-hide feature is turned off. Refer to the image below. 2. Drag the vertical scroll bar to view the portion of fitted rates. Note: In this tab or in any other tabs of the Output Window, you can right click to access a text-editing menu to copy/paste, format the fonts, or save the information to a text file. 3. Select the Forecast tab. OFM Forecast Analysis Fundamentals May 16, 2005 45 Viewing the Forecast and Output Window Features Schlumberger This tabbed page enables you to read the forecast (decline) equation, forecast rates and cumulatives/reserves. Scroll down to see the rest of the report. If you have multiple scheduled forecasts, each schedule has its own equation. 4. Select ORANGE_34:Ad_1A from the well name drop-down list, select the Forecast tab (in Output Window). The information pictured below displays. Schlumberger Private 5. Scroll down to see the rest of the report. 6. Select the Summary tab. OFM Forecast Analysis Fundamentals May 16, 2005 46 Select RED_4:Cl_3 again from the well list (and reselect the Summary tab).Viewing the Forecast and Output Window Features Schlumberger 7. 11.e. OFM Forecast Analysis Fundamentals May 16. so you can compare and evaluate your case. Select File>Save to Different Case. Remember that you may set up your forecast and keep working on it without saving the result. Working with Cases 1. equations. 10. 2005 47 . The Case dialog displays. Set a lower limit as shown. OFM keeps a copy of your working forecast. you cannot retrieve other information (i. scroll down and view the result.). The working forecast results in higher forecast rates. you will have two forecast results displayed in this Database Forecast tab. which uses a hyperbolic regression instead of an exponential regression in case1. 9. especially towards the end of the forecast period. Click on the Database Forecast tab in the Output Window (you may want to resize this window). This is our working forecast. per schedule. Once a forecast is saved to your database. etc. Name the new case Case2. 8. Note: Remember that the current forecast (working) is not saved yet. Right-click on the graph and select Limits>Reset. 2. correlation coefficient.. This tabbed page contains a summary of your forecast. The results shown are of the saved forecast (case1). one is of the saved forecast. and the other one is of the work-in-progress forecast. The rest of the fields are optional. Select the Database Forecast tab. The Current Case. Click OK. You can see that Case2 is checked (denoting the active case). Select Case1 from the Compare Case drop-down list. Now that you have more than one case saved to the database. Select Tools>Compare Cases. Select the Database Forecast tab and scroll down. OFM Forecast Analysis Fundamentals May 16. Schlumberger Private 6. The Case window displays. 5.Viewing the Forecast and Output Window Features Schlumberger 3. Select File>Cases. 2005 48 . as mentioned earlier. Note: Once you add a new case to the database. 8. 4. Click OK to close the window. 9. is the active case . 7. your working forecast is defaulted to that new case (but not saved until you do so). You can see that the Database Forecast Rate and Volume now reflects the information of Case2.Case2. you can select to compare the results of those two cases and view the comparison in the Output Window. Upon clicking the OK button. and most of the time would not yield the best-forecast possible for every well. The Auto Decline window displays. Select the Compare Cases pane (OFM automatically activates this pane when you set up Compare Cases). select Tools>Compare Cases and select None from the Compare list. 49 OFM Forecast Analysis Fundamentals May 16. Default Scenario . The following options are available from this dialog: • • • Cases .Restores the default values. This feature is designed to give users a baseline. Scroll down to see the rest of the comparison report.Viewing the Forecast and Output Window Features Schlumberger 10.Assigns the case name. You are strongly advised to check and modify (if needed) every individual forecast afterwards. 12. 2005 . If you have a filter list that contains many wells and would like to set up a baseline forecast case for all the wells in the list. Auto Decline Another useful tool regarding basic forecasting is Auto Decline. the Compare pane will disappear. Scenario . Note: To deactivate the Compare Cases pane. you can do it via Auto Decline.Sets up the scenario. Select Tools>Auto Decline. 13. 11. Click OK. Specifies the data range. OFM also provides the grouping option that pre-groups data before performing the forecast and facilitates output control options as saving/printing. Schlumberger Private OFM Forecast Analysis Fundamentals May 16. Click OK. Exercise 3 Auto Decline Feature Experiment with this Auto Decline feature. Exercise 4 Perform Forecast Analysis Perform the forecast on gas phase for a well of your choice. etc.Viewing the Forecast and Output Window Features Schlumberger • Range . 2005 50 . 14. and Water. The Edit Scenario dialog closes and you are returned to the Scenario Manager.Cut for Water Cut. 4. Water Cut vs.Cum for Cum. Click Close. 6. Cumulative Production. Time decline model to forecast the rates and reserves. Cumulative Oil and P/Z vs. Cumulative Gas.Additional Forecasts Schlumberger Chapter 3 Additional Forecasts In the previous session. OFM Forecast Analysis Fundamentals May 16. From the Variable Association section of the dialog. we used Rate vs. Click OK. etc. The Scenario Manager dialog displays.Oil analysis Use grid map tools Water Cut versus Cum. 2. Oil. Select ORANGE_32:Li_1C from the well list. 3. 5. You will successfully learn how to perform the following procedures within this workflow: • • Water cut versus Cum.Oil. and P/Z. Learning Objectives In this session you will spend some time with two other forecasting models. select Water Cut for Phase/Analysis. OFM also allows other common types of forecasting approaches using other variables such as Water Cut. Make sure you have Time set to Date. 2005 51 .Oil Analysis 1. Select Edit>Scenario Manager. Select the default scenario and click Edit. Additional Forecasts Schlumberger Notice that since we did not specify the Limiting Water Cut. you will need to specify the limiting water cut. 2005 52 . resulting in no forecasting at all. 9. Select the Historical Regression and Forecast tab. For End Water Cut. 7. OFM Forecast Analysis Fundamentals May 16. Therefore. Select Edit>Scenario Manager. for Start Water Cut select the Last Historical radio button. 11. Schlumberger Private 10. The Edit Scenario dialog displays. The Scenario Manager dialog displays. while the starting water cut is already higher than 95%. 8. OFM uses 95% water cut for the cut off point. Select the Default Scenario and click Edit. In the Forecast section of the dialog. select the Value radio button and enter a value of 99 (%) in the adjoining field. OFM Forecast Analysis Fundamentals May 16. there is not much that we can do. The graph displays. Take a look at the Reserves and EUR. Then click Close. Since the starting water cut is already high. Click OK. 2005 53 .Additional Forecasts Schlumberger 12. Select the Forecast tab. that is not a good approach in this case. The graph displays. 2005 54 . However. OFM Forecast Analysis Fundamentals May 16. Select Edit>Scenario.Additional Forecasts Schlumberger 13. the reserves will be increased significantly. 14. 15. Set up a lower limit on this curve as shown. 16. you can increase the reserves. For Starting Water Cut select Value and enter 98 (%) in the adjoining field. Click OK then Close. If you lower the starting water cut even more. Schlumberger Private Notice that even with a little lower water cut. many wells OFM Forecast Analysis Fundamentals May 16. 17. yet usually not enough to conduct an effective analysis. Fortunately. schedule your reserves (Remain or Total).Additional Forecasts Schlumberger The graph refreshes. Now that you know the value of EUR (~331 Mbbl). you may find a scattered set of pressure information. pressure data is not adequately available.Gas Analysis In most of OFM projects. Exercise 5 Schedule Your Reserves Switch the phase back to Oil. and Remaining Reserve (~14 Mbbl). Cum. P/Z vs. 2005 55 . For each individual well. you can get back to the Scenario and schedule your reserves correspondingly. The PVT Entity Name dialog displays. 1. and click Edit.Gas forecast to determine gas recoverables. Check the PVT information first. we will create a P/Z vs. and have comparable properties. Select one. their pressure data could also be of the similar ranges. 2005 56 . reservoir). In this lesson. You should have at least one PVT profile (named Default) in your PVT Entity Name list. we need pressure and gas production data. The Edit PVT Information dialog displays. Select Database>PVT. Schlumberger Private 2.e. As the name suggests. as well as PVT information. Select the PVT Data tab. Cum. OFM provides this capability of plotting discrete individual pressure points versus grouped (combined) cumulative gas. 3.Additional Forecasts Schlumberger may belong to the same entity (i. OFM Forecast Analysis Fundamentals May 16. With other parameters being similar (relatively). The Select OFM Table to Edit dialog displays. In this Demo2005 project. OFM Forecast Analysis Fundamentals May 16. 9. That is the field we want to load pressure data into. 5. there is a field in Monthlyprod table named Pressure. Close the PVT Entity Name window. Click Next button. 10. The Filter 8. and RED_4:Cl_3 from the list. 6. We will interactively add in pressure data from the Data Editor. well GREEN_6:Li_1C displays. 2005 57 . Filter by Completion icon. 11. From the Filter pane. click the by Completion dialog displays. Note: You may want to use the Data Loader to load them in.Additional Forecasts Schlumberger 4. ORANGE_19:Ad_1A. Select Database>Data. Click OK. Select the Monthlyprod table from the table list. 7. Select GREEN_6:Li_1C. yet you need to create the data file first. The next thing to do is to load some pressure data into this project. Click OK. enter the following: • • • • • • • 2900 at 1/1/1981 2700 at 2/1/1982 2500 at 5/1/1983 2300 at 1/1/1985 2200 at 12/1/1985 2000 at 7/1/1989 1900 at 1/1/1992 Schlumberger Private 14. Click Next to move to RED_4:Cl_3 and enter the following: • 3000 at 4/1/1980 OFM Forecast Analysis Fundamentals May 16. Click Next to move to ORANGE_19:Ad_1A and enter the following: • • • • • • 3500 at 1/1/1973 2800 at 8/1/1981 2650 at 3/1/1982 2400 at 11/1/1984 2100 at 3/1/1987 1850 at 11/1/1992 16.Additional Forecasts Schlumberger 12. 17. 2005 58 . Click away from the last cell. In the Pressure column. 13. Click away from the last cell. Click OK. 15. 19. OFM Forecast Analysis Fundamentals May 16. 20. OFM uses its default (calculated) values there. current. Make the selections shown in the image below. Since we did not specify the initial. Take a look at the graph. 2005 59 . you can see all individual well’s pressure points plotted together against the combined cumulative gas production. 21.Additional Forecasts Schlumberger 2500 at 1/1/1983 2000 at 3/1/1988 1900 at 7/1/1990 1800 at 11/1/1992 1700 at 4/1/1994 • • • • • 18. and abandonment P/Z. Select Group Data then select Analysis>Forecast to open a forecast window (if you do not already have one opened). Click away and then close the editing window. Click OK for the graph to be displayed. Select Edit>Scenario Manager and click Edit. 22. The Scenario Manager dialog displays.Additional Forecasts Schlumberger 23. 25. Observe the result from the Legend box. Verify that the Phase/Analysis is set to PZ and select the Historical Regression Forecast tab. Click OK. 2005 60 . OFM Forecast Analysis Fundamentals May 16. Select Edit > Scenario Manager. Click Edit. 24. Enter the following: • • • 4000 (psia) for Initial P/Z 1800 (psia) for Start P/Z 800 (psia) for End P/Z Schlumberger Private 26. Select the Historical Regression Forecast tab.Additional Forecasts Schlumberger 27. OFM Forecast Analysis Fundamentals May 16. Select Edit > Scenario Manager. The Scenario Manager dialog displays. Select From Fit for Current P/Z and unlock Initial P/Z (you will let OFM determine those values). 2005 61 . Click Edit. 28. OFM Forecast Analysis Fundamentals May 16. 2005 62 .Additional Forecasts Schlumberger Schlumberger Private 29. Click OK. switch the phase to gas and perform gas forecasting using the reserves obtained in this lesson. What kind of conclusion can you make from this analysis? 30.Gas. Cum. OFM Forecast Analysis Fundamentals May 16. The forecast graph displays. then Gas Rate vs. Exercise 7 Performing Additional Analyses Perform P/Z vs. Question Compare the result with previous result.Additional Forecasts Schlumberger Exercise 6 Performing Gas Forecasting Return to the Forecast Scenario. Click Next to move to GREEN_6:Li_1C. Save the results. Time analyses on the other two wells. 2005 63 . More advanced analytical skills regarding this method will be addressed in the higher levels of OFM training. You will successfully learn how to perform the following procedures within this workflow: • Use Fetkovich TCA OFM Forecast Analysis Fundamentals May 16. Production data for the entity are plotted against time on a dimensionless loglog scale. That method is based on a set of decline equations (documented in the Online Help. where the rates start declining). Fetkovich Type Curve. The ideal Fetkovich log-log type curve analysis assumes that the well rates will decline after a period of pseudo-steady state.Fetkovich Type Curve Analysis Schlumberger Chapter 4 Fetkovich Type Curve Analysis In the last chapter. Fetkovich Type Curve Analysis (TCA) is designed for late-time history matching and should not be applied to early-time analysis. under DCA equations). The plotted (real) curve is then matched with one of the provided Fetkovich curve. or close. you have used the empirical solution method to forecast production. Fetkovich Type Curve Analysis uses a set of “type curves” representing the typical performance of ideal (conventional) finite radial (flow) reservoirs. you will learn the basics of Fetkovich TCA functionalities in OFM2005. 2005 64 . Learning Objectives In this section. which also is fundamental for a more advanced technique. Technically. Users are required to “re-initialize” data (to the first point. and the real entity can be referenced to the ideal curve. denoting by a rather flat (constant) rate when it is plotted against time on a log-log scale. Expand the Well List node in the Filter pane and select Prod_Wells98.Fetkovich Type Curve Analysis Schlumberger • Perform Type Cure Match Using Fetkovich Type Curve Analysis (Late-Time) 1. 7. the other parameters in Model Description section of the dialog are grayed out. 3. 2005 65 . OFM Forecast Analysis Fundamentals May 16. Notes: • When you select Fetkovich Type Curve from the Solution list.txt. Open a Forecast window. 2. 6. Clear any previously applied filter. Associate the following on the Flow Model tabbed page. Select Edit>Scenario Manager and set this scenario as the default then click Edit. 4. 5. Select BLUE_5:Sc_0. Add a new case named Case3 to the project. so you will not override the previous forecasts. The Edit Scenario dialog displays. Otherwise. • If you have dynamic (data loaded into a table. Schlumberger Private 9. Click OK. Once you select either Fetkovich Type Curve or Analytical Transient from the Solution drop-down list. you can enter (static) pressure values in the Pressure group box. Select the Parameters tab and accept the default parameters to start history matching. • 8.e. legend to get the desired output) OFM Forecast Analysis Fundamentals May 16. 2005 66 . (You will have to add the header.Fetkovich Type Curve Analysis Schlumberger The known set of reservoir parameters that Fetkovich TCA uses can be read from there. resize the graph. The graph displays. associate the variable at the Flowing Pressure list. the Historical Regression tab (in Empirical method) disappears and substituted by the Parameters tab. i. monthly) pressure data and want to use them. 12. 2005 67 . Note: OFM may display a dialog with a Reinitialize Data Tip as shown below. OFM Forecast Analysis Fundamentals May 16.Fetkovich Type Curve Analysis Schlumberger 10. Reinitialize your data by right-clicking on the graph. Position your cursor at your desired data point and click to highlight the point. Select Reinitialize. 11. Right-click and select Done from the shortcut menu. A shortcut menu displays. 2005 68 . Click OK.Fetkovich Type Curve Analysis Schlumberger 13. OFM runs the matching algorithm and returns the following: OFM Forecast Analysis Fundamentals May 16. Schlumberger Private 14. Select Tools>Typecurve Match. Position your cursor over the real curve until the cursor changes to a fourheaded arrow. Note: You can also adjust the data fitted curve (Dark Green) by positioning the cursor over that curve and when a hand appears. Your data has been reinitialized. 15. click the curve and drag it to your desired location then release the mouse. drag it and move it (remember the “initial” point of the decline period) closer to the displayed type curves. Fetkovich Type Curve Analysis Schlumberger Note: You may get a failure message as the result of this operation. In this case, go back to the Scenario>Parameters tab and adjust the values of your matching parameters and re-run the Typecurve Match command. If you have any questions, please feel free to seek help from your instructor. 16. Select Edit>Scenario. 17. Click on the Parameters tab. Observe that after running the matching algorithm, OFM returns the calculated results for the b value and Permeability, Skin factor, Drainage area (if you are performing both earlyand late-time analysis). 18. Select the Flow Model tab and clear the Late-Time Only checkbox (just an exercise). 19. Close the dialog and rerun the matching algorithm. The program returns a set of parameters. 20. Clear b value and Permeability boxes, check Skin factor and enter 45 in the Estimates box, check Drainage Area and enter 300 in the Estimates box. 21. Click OK. 22. Select Tools>Typecurve Match. The new result returns: OFM Forecast Analysis Fundamentals May 16, 2005 69 Fetkovich Type Curve Analysis Schlumberger Question Compare this with the previous result, what do you see? 23. Select Edit>Scenario. 24. Select the Parameters tab. Based on the returned skin factor, you would have a good idea of what the next estimate Skin factor should be. Remember that you can vary all four parameters in your matching criteria. 25. Check the Permeability box, and enter 30 (md). 26. Check the Skin factor box, and enter 60. 27. Check the Drainage area box, and enter 700 (acre). 28. Check the b value box, and enter 0.3. 29. Click OK. If required, re-initialize your data. 30. Select Tools>Typecurve Matching. The graph displays and the results reported in the Legend box are different. Schlumberger Private OFM Forecast Analysis Fundamentals May 16, 2005 70 Fetkovich Type Curve Analysis Schlumberger 31. Edit the Scenario. Select the Parameters tab and examine the return values of the matching parameters. Keep repeating the operation by supplying better estimates, running history match, until you get a good match. Do not forget, these parameters are really important. By changing the values of Wellbore Radius, Net Pay, and Porosity, OFM Forecast Analysis Fundamentals May 16, 2005 71 2005 72 . For example. Click on the Matching Calculation Settings and this window appears: Note: You can select to match on production rate. One of the reasons could be that it does not converge after a certain number of iterations. or cumulative production. incremental production. OFM Forecast Analysis Fundamentals May 16. You can also specify the number of iterations and the tolerance. you can run the matching algorithm with this set of parameters: Schlumberger Private Note: Sometimes you will get a matching failure message.Fetkovich Type Curve Analysis Schlumberger the magnitude of your matching parameters is strongly affected. Check the Late-Time Only box. OFM will run the forecast and display the forecast results. 2005 73 . Move the real curve closer to the type curves. Remember. and then select Tools>Typecurve Match. 35. OFM returns the calculated match parameters (which normally will be different than the estimates you entered). Question Examine the results. 37. Click on Update to use the Results as Estimates for the next run. It looks like we’ve got better reserves. 36. What conclusion can you make? 34. After running the matching algorithm.Fetkovich Type Curve Analysis Schlumberger 32. The result displays: Note the values in the Legend box. OFM Forecast Analysis Fundamentals May 16. You may want to compare it with the forecasts of other methods. 33. or click on Revert the other way around. Select Tools>Forecast. the settings on your Forecast tab are of your default setting (Current Scenario). Select Edit>Scenario. and all the pressure information is grayed out. Note: Review the values of your reserves in this forecast. Click OK. Note: After running Fetkovich Type Curve analysis (Late Time and all). 2005 74 .Fetkovich Type Curve Analysis Schlumberger 38. Select Edit>Scenario and select the Parameters tab. your matching parameters can be used back in Empirical Solution method to get a better decline estimation. the only matching parameter used is the b value. You can see in Late Time analysis. Schlumberger Private OFM Forecast Analysis Fundamentals May 16. Select BLUE_5:Sc_0 from the well list. based on the phase and the technique that they select to pursue. In other words. the users are required to know more about their reservoirs/formations to effectively use this tool. 2. handling a variety of different parameter combinations. 3. OFM allows users to specify different types of reservoirs/formations.Analytical Transient Solutions Schlumberger Chapter 5 Analytical Transient Solutions Fetkovich Type Curve method uses a particular set of reservoir parameters. Unwanted results could be the product of incorrectly specifying reservoir parameters and/or matching criteria. Make sure that you have a forecast window opened. Learning Objectives In this section. From the Properties pane verify that you are on Oil phase. 2005 75 . OFM Forecast Analysis Fundamentals May 16. Therefore. except that you have to describe your model. (Advanced training on this topic is addressed in other OFM courses. The applicability of Fetkovich TCA is somewhat limited. you will learn to set up a basic forecast case using Analytical Transient Analysis. Select Analytical Transient Solution from the Solution list. You will successfully learn how to perform the following procedures within this workflow: • • Set up basing forecast case Combine all three solutions Schlumberger Private Using Analytical Transient Solutions 1. you can always claim that Fetkovich TCA is a special case of Analytical Transient Solution.) We will then pull everything that we have learned together to combine all three solutions to perform the forecast on a well that does not have good production data (or does not even have production data). The new solution (only available in OFM 2002 and later versions) is called Analytical Transient Solution. The usage of Analytical Transient Solution is very similar to Fetkovich TCA. enter the following values: • • • Wellbore Radius .0.0. Select the Parameters tab. To be consistent with what we did in the Fetkovich TCA lesson.3 (fraction) OFM Forecast Analysis Fundamentals May 16.20 (ft) Porosity . 2005 76 .2 (ft) Net Pay .Analytical Transient Solutions Schlumberger Schlumberger Private 4. Select Edit>Scenario and select the Parameters tab. Click OK. model description the same.Analytical Transient Solutions Schlumberger 5. 7. Exercise 8 Compare the Results Compare this result with the one you obtained using Fetkovich TCA previously. If your curve has not been reinitialized (from the previous exercise). 2005 77 .) 8. 6. do it now. Take a look at the returned (matching) parameters: Schlumberger Private 9. what would possibly be the contributing reason(s) for the differences (if any)? OFM Forecast Analysis Fundamentals May 16. What kind of conclusion can you make? (Pay attention to the model description. With the formation parameters the same. Compare these values with ones obtained from previous Fetkovich TCA. Select Tools>Typecurve Match. Click OK to display the graph. Specify a Skin Factor of 45 and a Fracture Conductivity of 500. Uncheck the other parameters.Analytical Transient Solutions Schlumberger 10. 2005 78 . 13. Move the real curve closer to the type curves (and the fitted data curve) and select Tools>Typecurve Match. 12. Note: Depending on your associated choice in the Model Description. Schlumberger Private 11. Describe the model as shown below. Select the Parameters tab. Re-initialize your data. Select the Flow Model tab. your next choice (in that description) and your match parameters list change. OFM Forecast Analysis Fundamentals May 16. 18. Always keep in mind that anything that you make may affect the validity of your results. Save the result when you are satisfied with it. There will be a lot of interactive learning with this kind of analysis and environment. match on cumulative rate instead of production rate. Assume that we know the reservoir model and have formation parameters available. you will probably encounter quite a few “Type Curve match failure” messages. The next exercise demonstrates the capability of combining all three types of solutions you have learned to forecast oil production on a well that has a brief production history.e. 17. Set the Method to User and enter User value of 0. Note: Let your instructor know what you find in your experience. If needed. 16. From the Properties pane select Empirical solution. we could start the forecast from a different approach. Examine the results from the Output Window and experiment with the match parameters by different combinations and estimate values. 2005 79 . OFM Forecast Analysis Fundamentals May 16. 19. Remember that you can specify your own Matching Settings. increase number of iterations/tolerance). Examine the results on the graph and legend box.Analytical Transient Solutions Schlumberger 14. etc. Select BLUE_1:Ge_6 from the well list. Note: During this lesson. The (Empirical) forecast may display. Skinf. 15. Schlumberger Private Exercise 9 Perform an Analytical Transient Analysis Pick a well of your choice and perform Analytical Transient Analysis on it. Locate the b Value properties. you see more type curve parameters such as Cr.6. a visual trend may be unreliable. Notice that with only a few data points. change the matching criteria (i. Change the Fit Type to Hyperbolic method. It is due to either incorrect parameter specifications or the algorithm not converging. Notice that with your model description. Select Edit > Scenario. 21. 23. Select the Forecast tab and specify the following: Schlumberger Private 22. Click OK and the graph shows (you may have to set the limits). OFM Forecast Analysis Fundamentals May 16. 2005 80 . The Current Scenario dialog displays. Save the forecast.Analytical Transient Solutions Schlumberger 20. Analytical Transient Solutions Schlumberger 24. For this schedule. 25. 26. Select Edit>Scenario. use Analytical Transient Solution method and specify the following on the Forecast tab: Schlumberger Private OFM Forecast Analysis Fundamentals May 16. 2005 81 . Select the Forecast tab and add Schedule #2. 2005 82 . Click OK. Enter these values on the Parameters tab: 28. The graph displays (both working and saved forecasts). Click OK.Analytical Transient Solutions Schlumberger 27. 32. Select Tools>Typecurve Match. Change Schedule #2 to Empirical. Select Edit>Scenario. 34. Save the forecast. 31. 33. Schlumberger Private 30. OFM Forecast Analysis Fundamentals May 16. Select the Forecast tab in the Output Window and find the section for Schedule #2. 29. you can distinguish the two portions of the curve. with different hyperbolic b values. Note: Pay attention to the saved forecast (in Cyan). 43.Analytical Transient Solutions Schlumberger 35. Select Tools>Typecurve Match. OFM Forecast Analysis Fundamentals May 16. 36. use Fetkovich Type Curve. Click OK. 38. 2005 83 . Exercise 10 Pick a well that does not have good production history (or one that does not have production at all) and do the forecast. 42. Add Schedule #3. Save the forecast.3 39. 40. Select Edit>Scenario. Switch back to Empirical to see the saved forecast. Click on the Forecast tab (Output Window) to check the result. 37. 41. Specify the following on the Forecast tab: • • • • • Schlumberger Private Start Time – Months from End Start Rate – Previous End Time – Months from Start and in the adjoining field 36 months Decline Type – Exponential Decline Rate – User Defined and in the adjoining field 0. On this schedule. Close the forecast window. Schlumberger Private OFM Forecast Analysis Fundamentals May 16. 45. 2005 84 .Analytical Transient Solutions Schlumberger 44. Clear the filter and return to the Basemap. Assign unit to the variable accordingly. This variable retrieves (oil) Remaining Reserves for the selected entity (group/well) based on the specified case. We will then create variables to return remaining reserves and estimate ultimate recoverables. This variable adds individual forecasts (oil rates) together for a group of wells. We will use the forecast results saved in Case1.) can be retrieved via calculated variables and displayed/used in other modules such as report. rates. Assign unit and multiplier to the variable. “Case1”.Retrieving Forecast Results Schlumberger Chapter 6 Retrieving Forecast Results Forecast information (reserves. we will create variables to return rates on group and individual wells. “oil”.OilonGroup = @Forecast( date. "oil". Create a calculated variable named FCST. The definition of this variable is: FCST. 2005 85 .OilonGroup to retrieve forecast oil rates on a group of wells. 5. Create a calculated variable named FCST. OFM Forecast Analysis Fundamentals May 16. plot. Assign unit to the variable accordingly. and reporting is a prerequisite in this lesson. Learning Objectives In this section. The definition of this variable is: FCST. 3. Create a calculated variable named FCST. "Case1". refer to the Online Help (or any training material that applies). In this session.RemRes. Prerequisites Knowledge of calculated variables. 1 ) 6. If you have any problems.GroupofOil = @Forecast( date. plotting. “sum” ) 4.GroupofOil. The definition is: FCST. "group" ) 2. you will successfully learn how to perform the following procedures within this workflow: • • • Create variables to return remaining reserves Estimate ultimate recoverables Use forecast result Calculated Variables 1.RemRes = @DcaResults( "oil RES". etc. "Case1". GroupofOil to the report. From the Filter pane.Oil. Click OK.txt file.EUR. 13. Select Analysis>Report to open a report window.Retrieving Forecast Results Schlumberger 7. The report displays. We will use these variables on the report first. 9. Create a calculated variable named FCST.EUR = @DcaResults( "oil EUR". OFM Forecast Analysis Fundamentals May 16. Assign unit and multiplier to the variable. In the Select section of the Edit Report dialog enter Date. Select Edit>Report Parameters. 2005 86 . This variable retrieves (oil) Ultimate Recoverables for the selected entity based on the specified case. select Open and select the Prod_Wells98. Monthlyprod. 10. 11. Add FCST. Select Edit>Report Parameters. "Case1". Schlumberger Private 14. FCST. Group the data. 1) 8. 12. 15. expand the Well List node. Right-click.OilonGroup. The definition is: FCST. 20. 17. 18. The definition is: FCST.OilRate.Retrieving Forecast Results Schlumberger 16.OilRate to the report as shown below. "Oil".OilRate = @Forecast( Date. 22. Exercise 11 Verify Report Results Bring up a Forecast window and verify the results (by comparing the retrieved values on the report and the saved values on the forecast). Create a variable named FCST. for individual well the group and the sum options are the same.EUR) to the report.RemRes and FCST.e. Group the data to regroup all the wells in the list. Add FCST. “Case1” ). 2005 87 . "Case1" ) 21. These values are the results of your forecast on the group. Use the Next and Previous buttons to navigate through all the wells. Thus for individual well. 19. “Oil”. @Forecast( Date. Add the other two variables (FCST. i. Constant values of Reserves and Recoverables are reported. Click OK. As you can see. OFM Forecast Analysis Fundamentals May 16. you can even omit this last argument in the variable definition. Associate the unit properly to the above variable. not the sums of individual reserves and recoverables. (In other words. 2005 88 . The Settings dialog displays. 26. OFM Forecast Analysis Fundamentals May 16. Schlumberger Private Notice that if you omit the last argument.Retrieving Forecast Results Schlumberger 23. “group” is the default option). the @Forecast() function takes the “group” option. Select Tools>Settings>Group. If the variable has been created this way (without the last argument) you still want to retrieve the summed values. Scroll down to see the results. you can specify an OFM option from the Tools>Settings menu. 24. 25. Click OK. Check the Sum individual well forecasts when grouping wells option. Click OK. 28. Verify the result.CalDay. Select Analysis>Plot. Reverse the operation (by clearing that group option). and recoverables.GroupofOil versus Date. 29. OFM Forecast Analysis Fundamentals May 16. Exercise 12 Create Variable to Retrieve Data Select a few wells and perform forecast on gas phase.Retrieving Forecast Results Schlumberger 27. Your plot should look similar to the one pictured below. reserves. FCST. 30. 2005 89 . Create variables to retrieve forecast gas rates. Add the following variables . Regroup the wells and the report displays. Save them to another case.OilonGroup and FCST.Plot Oil. The Edit Plot dialog displays. . You should expect to see the forecast portion consistent (in trend) to the historical portion. OFM Forecast Analysis Fundamentals May 16.Retrieving Forecast Results Schlumberger 31. forecast parameters) If you perform forecast using ratios or cuts and would like to retrieve those variables. 2005 90 .e. Example: Schlumberger Private Exercise 13 Create Bubble and Grid Maps Create bubble map and grid map of oil RES and EUR. the two forecast variables are the same. Notes: • • • @Forecast() function can only retrieve rates @DcaResults() function retrieves constants (i. Navigate through all the wells in the list and see their plots. On individual well. use the @DcaCalc() function Congratulations! You have completed the OilField Manager – Forecast Analysis Fundamentals course.
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