PROJECT 3

WATER FLOODING

This water flooding exercise is going to teach us how to develop a field-scale black oil reservoir simulation model using CMG BUILDER and IMAX. We will analyze production data and also discuss how to in-fill drill/schedule an injection well

Developing a “Black Oil” Model using BUILDERCreate a working directory somewhere on your disk and put the map files that accompany this tutorial into this directory. 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 where you stored the map files. 4. Call the project IOR. 5. Click OK to exit back to the Launcher. 6. You should now have this directory displayed. Opening BUILDER You can open BUILDER by double clicking on the appropriate icon in the LAUNCHER. Choose: • IMEX Simulator →Field Units →Single Porosity→ Starting date 2008-01-01 → Click OK twice.

FIGURE 1: Reservoir Simulator Settings

Creating the Simulation Grid (structural data) 1. Click on FILE (on the menu bar, top left), then OPEN MAP FILE. 2. Choose Map Type – Atlas Boundary format and ft for Units for x/y coordinates.3. Select the Top-of-Structure map file called structural_INPUT.bna by clicking on the

Browse button and locating the file.4. Click OK.

FIGURE 2: New IMEX Dataset with Contour Map Open

5. Maximize the screens for a better view by clicking on the window maximize button (the square in the top right of the windows).

6. Click Reservoir (on the menu bar). Create grid, select Cartesian and specify a 15(I-direction) x 12 (J-direction) x 1 (K-direction) grid.

7. Enter 15*500 in the I direction box (meaning all 12 columns in the I-direction will be 500 ft in length).

8. Enter 12*500 in the J-direction box (meaning all 9 rows in the J-direction will be 500ft in length).

9. Click OK.10. Hold down Shift key and hold down left mouse button to move (pan) grid.11. Hold down Ctrl key and hold down left mouse button to rotate grid.

Figure 3: Cartesian Coordinate

13. Align the grid with the reservoir boundaries so that a grid block boundary lies along it, and the grid covers the whole map area.

14. Change display control to Probe mode by clicking on this toolbar button on left hand side.

FIGURE 4: Contour Map with Orthogonal Corner Point Grid

15. Click on the Specify Property button (top middle of screen) to open the General Property Specification spreadsheet as shown below.

FIGURE 5: General Property Specification Spreadsheet

16. Select the box for layer 1 under the property column labeled Grid Top. Right click in this box and select the Geological Map option as the data source.

17. Click the Values in file1 button, then Browse for and select the top-of-structure map file called structural_INPUT.bna (it should already be selected from previous actions).

FIGURE 6: Specifying a Geological Map for a Property 18. Click OK to return to the spreadsheet type window.

19. Repeat this action for Grid Thickness in layer1 box, but this time selects isopach_input.bna in the Values in file1box. Also, enter 1 in the times box (still on the property specification menu) in order to allocate 100% of the total thickness map to layer 1in the

grid. Click OK.

20. Click the Calculate Property button and click on OK to populate the grid with top-of-structure and grid thickness data (this operation is performed by BUILDER using the specified map data to interpolate grid cell values).

21. Change the view from IJ-2D Areal to 3-D View (in the upper left corner!!).

FIGURE 7: 3D View of Reservoir after Property Specification 22. 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.

23. To remove the contour map from the display, click the right mouse button while the cursor is anywhere in the display area. Select Properties from the displayed menu (bottom of list), Maps from the tree view; and finally uncheck the Show Map Contours Lines and Fault boxes. Press OK.

FIGURE 8: Removing the Contour Map from the Display Assigning Porosity & Permeability to the Model 24. Repeat the above process for Porosity (i.e. similar to step #19), but select the map porosity_input.bna.

FIGURE 9: Property Specification Spreadsheet with Grid Top, Thickness & Porosity Specified 25. Repeat the above process for Permeability (i.e. similar to step #19), but select the map permeability_input.bna.

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

FIGURE 10: Property specification for Permeability K & J

27. Perform the same with Permeability K and select EQUALSI. Press the OK button.

28. Select Volume Modifiers and input a value of 10.

29. Leave the General Property Specification section and then do Calculate Property. 30. Double-click on Rock Compressibility in the tree view menu and input 3E-6 in the rock compressibility box, 4800 psi in the reference pressure box and OK. Units will be applied automatically.

31. This would be a good point to save the data set you are working on. Click File then Save As. Save file as project1.dat. Creating PVT Data 1. Click the Components tab in the tree view. Double click the MODEL keyword.

FIGURE 11: Components Tab in the Tree View

2. Select None of the above. Launch detailed dialog

FIGURE 12: Quick Model options

Figure 13: Model

3. Select none of the above, in model tab select black oil. Press the “OK” button. Double click the PVT region1. 4. Type 190 (deg f implied) in the Reservoir Temperature box. 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 50 in data entry window. Change the Gas Density box to display Gas Gravity and type .65 in the data entry window. For water density type 60.7818 lb/ft3; water formation volume factor is 1, water compressibility is 3.27E-6 5. In the Reference Pressure for Water box, enter a value of 14.698psi, for water viscosity put 0.34 and leave the rest of the options at their default values.

6. Click OK.

Double-click on “PVT Region: 1” in the tree view and select the PVT Table tab to view the black oil PVT data.

Figure 14: PVT Regions

Insert numbers for parameters found below

FIGURE 15: IMEX PVT Table with Values Generated using the Quick Black Oil Model

7. Close the PVT Table window. 8. 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. Copy and paste relative permeability’s from excel file for water oil Table. 4. Change the relative perm table to liquid gas table and copy and paste the Krg and Krog from excel file to the table. 5. Press Apply and then OK. Press OK again to get out of the Rock Types window. A table containing the relative permeability curves will appear. 6. The Rock Fluid section should have a green check mark. Save the file at this time.

Figure 16: Relative permeability tables

FIGURE 17: Plots for RockType 1

Creating Initial Conditions

1. Click the Initial tab on the tree view of Builder.2. Double click on Initial Conditions.

Figure 18: 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: 4800 (psi implied) in the Reference Pressure window 9290 (ft implied) in the Reference Depth window 9500 (ft implied) in the Water-Oil Contact window

5. Leave the other boxes blank. 6. Click on Apply; then OK.7. 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. 8. At this point it is advisable to save the data again by selecting File from the top menu and

Save As.

Creating Trajectories and Perforations

Once we have created the static model, we will now incorporate the trajectory and perforation information into the model.

1. Click on Wells & Recurrent tab in the tree view. You already can see five wells.

FIGURE 19: Creating trajectories

Figure 20: Elevation Settings

2. Double click on well1, select ID & Type tab and change the type of the Well 1 to producer. Under constraints check constrain definition and change the constraint to operate with Min bottomhole pressure of 28 psi; repeat these steps for all the wells and convert them to producers.

FIGURE 21: Well ID & Type

3. Double-click on dates and a range of producing from the wells for 1 year.

4. Under the Well Tab at the top of the screen press the button and select Create Trajectories from completions PERFs and type the zero elevation for all the wells.

5. Under the Well Tab at the top of the screen Press the button and select Trajectory Perforation intervals then double click on read file and open PERFS_Feet.perf, for file unit selection choose field. Press open.

6. Click on quick Perf Tab, on perforation status choose perforated and check all grid layers, Press OK

7. Press Calculate MD values

8. Click the Apply and then OK

FIGURE 22: Trajectory Properties Window Data. Well and recurrent tab should now be green.

9. Under the Well Tab at the top of the screen press the button and select Well completions perf.

Figure 23: Well Completion Data

Figure 24: Selecting Reference Layer

Now all the major tabs should be green!  Save your file and exit the Builder.

Simulation Using IMEX Black Oil Simulator

1. Drag and drop the project1.dat file to the IMEX icon.

2. On the appearing window press the button run immediately. It should terminate the program without any fatal error. 

2D Visual Representation of Simulation Results using RESULTS 2D

Drag and drop simulation generated project1.irf file on Results 2D icon. Click on add curve and choose the well and parameters that you intend to plot

Figure 25: Results graph

2D Visual Representation of Simulation Results using RESULTS 3D

Drag and drop project1.irf file on the Results 3D icon

Choose the map that you want to use during your investigation

Figure 26

HOW TO CHANGE THE WELL OPERATION CONDITIONS 

1. Drag and drop the project1.dat  on the builder icon 

2. Under well and recurrent tab; double-click on wells

3. Choose the well that you want to turn in injector 

4. Under ID& Type, change the well to injector unweight 

5. Go to the constraints and choose operate BHP and max value 14700 psi

6. Go to the options tab and shut in the well. Apply → OK 

7. Scroll the date to the date that you want to start injecting water 

8. Go to option tab and change the status of the well to open 

9. Go to the guide rate and type 250 bbl/day of water injection Apply → OK 

Save the file as a new file for water injection

HOW TO CHANGE INJECTOR SCHEDULE

Assume that we want our injector to be shut in for 90 days after starting the production. It means that we want to have 90 days of primary production then we want to inject water for 90 days and shut the injector again after 90 days, we can follow the steps below.

In the main builder window click on injector well, and under Type make sure you choose Unweighted injector

-Figure 27

Figure 28: Well Events 

Go to your injector, click on the Options tab, and check the Status box and change it to SHUTIN then click Apply.

Figure 29 Then scroll the date down to 2007-02-01, and once again, click on the Options tab, then change the status to OPEN, then click Apply. 

Figure 30

 Now scroll the date to 2007-05-01, click on the Options tab, and change the status to SHUTIN. 

Figure 31 

If you look on the left hand side, the injector is initially shut in, then opened on 2007-02-01, and then shut in again 90 days later on 2007-05-01.

Now, for the project you are required to develop a small-scale waterflooding. For a fixed time period, you are required to compare the performance of one water injector, which may be a new well or one of the producers, in terms of additional oil recovery. The location of the injector could be critical so you may want to check the pressure and saturation profiles at the end of the primary production prior to make any decision in regards to drill a new injection well or to convert one of the producers into an injector.