CMG tutorial

Institute of Petroleum Engineering University of Tehran

CMG 2006.10 Tutorial

Building, Running and Analyzing a “Black Oil” Reservoir Simulation Model

Using

Builder 2006.10

&

IMEX 2006.10

Creating a “Black Oil” Model using Builder 2005.15 Create a working directory somewhere on your disk.

Starting CMG Launcher 1. Start the CMG Launcher by using the icon on your desktop, or by going through the Start menu and selecting Programs/CMG/Launcher. 2. Select menu item Projects, then Add Project. 3. Browse for the directory you created. 4. Call the project Tutorial. 5. Click OK to exit back to the Launcher. 6. You should now have this directory displayed.

Opening BUILDER 2006.10 1. Open Builder 2006.10 by double clicking on the appropriate icon in the Launcher. 2. Choose: ·

IMEX Simulator, Field Units, Single Porosity

·

Starting date 2010-01-01

3. Click OK twice.

Creating the Simulation Grid (structural data) 1. Maximize the screens for a better view by clicking on the window maximize button. 2. Click “Reservoir” (on the menu bar) and “Create Grid”. 3. Select Cartesian and specify a 21 (I-direction) x 21 (J-direction) x 11 (K-direction) grid. 4. Enter 21*60 in the I-direction box (meaning all 21 columns in the I-direction will be 60 feet in length). 5. Enter 21*60 in the J-direction box (meaning all 21 rows in the J-direction will be 60 feet in length). 6. Click OK.

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The model in the main window should look like this:

7. Change display control to Probe mode by clicking on this

toolbar button on left hand side.

8. Click on the Specify Property button (top middle of screen) to open the General Property Specification spreadsheet. 9. Select the box for layer 1 under the property column labeled Grid Top and type 4000 (meaning the top of the reservoir is in the depth of 4000 feet). 10. Select the box for Whole Grid under the property column labeled Grid Thickness and type 20 (meaning all 11 rows in the Z-direction will be 20 feet in height).

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11. Click OK to leave the General Property Specification section. The Calculate Property option will automatically appear. So, press OK to populate the grid with top-of-structure, grid thickness and porosity data. Press OK to any messages that appear. 12. Change the view from IJ-2D Areal to 3D View (in the upper left corner!!).

13. Click on the Rotate (3D View) button

(from the toolbar) to rotate the display by holding down the left mouse

button and using the cursor to move the model. Hold down the Ctrl key with the left mouse button and move the mouse toward the bottom of the screen to zoom in or move the mouse to the top of the screen to zoom out.

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Assigning Porosity & Permeability to the Model 14. Select the box for Whole Grid under the property column labeled Porosity and type 0.3. 15. Select Permeability I from the list on the panel and enter the following: Layer 1

5

Layer 2

100

Layer 3

20

Layer 4

20

Layer 5

20

Layer 6

100

Layer 7

20

Layer 8

20

Layer 9

100

Layer 10

20

Layer 11

20

16. Select Permeability J and right click in the Whole Grid box. Select EQUALSI then OK.

17. Do the same with Permeability K and select EQUALSI. In the first box select * and then enter a value of 0.01 in the second field (this applies a Kv/Kh ratio of 0.01). Press the OK button.

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18. Press OK to leave the General Property Specification section, and OK to calculate the newly specified properties (as the option for calculating these properties will automatically appear).

19. Double click on Rock Compressibility in the tree view menu and input 1E-6 in the rock compressibility box. Units will be applied automatically; you should now have the Green check mark for Reservoir section. 20. This would be a good point to save the data set you are working on. Click File then Save As. Save file as Tutorial.dat.

Creating PVT Data 1. Click the Components tab in the tree view. Click the Quick Fluid Model keyword.

2. Check on Launch dialog to create a quick BLACKOIL model using correlations then press the “OK”. 3. Enter 130 (deg F implied) in the Reservoir Temperature box. Generate Pressure data up to 5000 psi. For Bubble Point Pressure, select the “Value provided” option and enter a value of 2500 psi. For the Oil Density option, select “Stock tank oil gravity (API)” as the type of gravity value you want to use and enter a value of 35

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in data entry window. Change the Gas Density box to display Gas Gravity (Air=1) and type 0.65 in the data entry window. 4. In the Reference Pressure for Water properties box, enter a value of 3000 psi and leave the rest of the options at their default values and Click OK.

5. Double click on “PVT Region: 1” in the tree view and select the PVT Table tab to view the BLACKOIL PVT data. For this example, the data shown in this table was generated using the information entered in the “Quick black oil model” window. However, it is also possible to directly enter or edit values in the PVT Table. These values can also be updated by using your mouse to select points on the plots associated with the PVT Region, and dragging the points to the desired location. Please note that the “IMEX PVT Regions” window has to be open while using your mouse to change the points on the plot.

6. Close the PVT Table window. Tutorial IMEX BUILDER 2006.10

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7. The Component section should have a green check mark now.

Creating Relative Permeability Data 1. Click the Rock-Fluid tab in the tree view. 2. Double click on Rock Fluid Types in the tree view. A window will open. Click on the

button and

select New Rock Type. 3. Press the Tools button (on the “Relative Permeability Tables” tab) and select Generate Tables using Correlations.

Enter the following parameters for the analytical relative permeability curves generation. SWCON 0.2 SWCRIT 0.2 SOIRW 0.4 SORW 0.4 SOIRG 0.2 SORG 0.2 SGCON 0.05 SGCRIT 0.05 KROCW 0.8 KRWIRO 0.3 KRGCL 0.3 KROGCG 0.8 All Exponents 2.0 4. Press Apply and then OK. Press OK again to get out of the Rock Types window. A graph containing the relative permeability curves will appear.

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5. The Rock Fluid section should have a green check mark. Save the file at this time.

Creating Initial Conditions 1. Click the Initial Conditions tab on the tree view of Builder. 2. Double click on Initial Conditions. 3. Select Water, Oil as the initial fluid in the reservoir to perform a Gravity-Capillary Equilibrium Calculation. 4. Type the following values in the available fields: 3010 (psi implied) in the Reference Pressure window 4010 (ft implied) in the Reference Depth window 4500 (m implied) in the Water-Oil Contact window 5. Check on Constant Bubble Point Pressure (PB) and enter 2500 psi. 6. Leave the other boxes blank.

7. Click on Apply; then OK. 8. You should now be back in the main Builder window with all tabs showing a green checkmark in the tree view, except for the “Wells & Recurrent” tab. 9. At this point it is advisable to save the data again by selecting File from the top menu and Save.

Adding Production/Injection Wells to the Model Once we have created the static model, we will now add production and injection wells to the model. 1. Click on the Wells & Recurrent tab and choose Well New. 2. In the pop-up window type a name for the well.

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3. Click on Constraints in the tabs on the left. 4. Check on constraint definition and select OPERATE under the property column labeled constraint. Select STO surface oil rate under the property column labeled Parameter and MAX under the property column labeled limit/Mode. Enter 750 bbl/day as the value and click OK.

5. Expand Wells (1) and Prod-1 and double click on 2010-01-01 PERF on the tree view.

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6. Click on the Perforations tab on the pop-up window. 7. Click on the Begin button. 8. Select Plane 11 of 11 from the View Control Bar in the main window.

9. Click on the top right block (21,1,11) so that the Well Completion Data looks like below:

10. Click on Stop and then OK. 11. Well-1 is added to the model in the main window:

12. Now go back to main Builder window and double click on Dates (1) on the tree view. 13. In the pop-up window, click on Add a range of dates: button on the right. 14. Enter date from 2010-1-1 to 2021-1-1 by clicking on the button next to each item. 15. Select 1 Month as time step and click on OK twice.

16. Close the Simulation Dates window. Tutorial IMEX BUILDER 2006.10

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Now all tabs in the main Builder window should have a green checkmark in the tree view. This means the model is ready.

Running the IMEX Dataset 1. Go to the main Builder menu and select Tools / Validate with Simulator. Click on Yes to save the file before running. The following window will pop up:

2. Check on Run normal immediately and click on the Run / Submit button. 3. If there are no errors, the window will show you the progress of the run. When finished, a brief summary of results will be displayed

Reviewing the Simulation Results using RESULTS GRAPH and RESULTS 3D We can now look at the simulation run and compare it with the historical data and see how the reservoir would perform. 1. Drag and drop Tutorial.irf onto the Results 3D 2006.10 icon. 2. Select 3D View and Oil Saturation as the property to show. 3. Click on the

button to show saturation change vs. time.

4. Close the window. 5. Drag and drop Tutorial.irf onto the Results 3D 2006.10 icon. 6. Click on the Add Curve icon

.

7. Select the file to display data from as Tutorial.irf. Select curve parameter Cumulative Oil Rate SC. Choose Well-1 for the Origin and then click OK.

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8. Click on the

button.

9. In the tree view, right click on Plot 2 and select Add Property Vs. Distance. 10. Select Linear Path from UBA 21 1 11 to UBA 1 21 11. 11. Select Oil Saturation for property and 2021-01-01 for Time. 12. Click on Add Curve button and then OK.

Tasks 1. Plot average reservoir pressure vs. time. 2. Plot saturation change vs. time for a block 21 1 11. 3. Define Well-1 in layers 9 instead of layer 11 and compare cumulative oil produced with previous model. 4. Define a water injection well in the opposite corner of the model with a rate of 500 STB/day and compare cumulative oil produced and average reservoir pressure. 5. Raise the injection rate to 2000 STB/day and repeat previous step for the results.

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