build a mode lfrom scratch in petrel_1

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Build a Dummy Model in Petrel from Scratch This document helps new users to get familiar with basic/fundamental yet essential functionalities by going through step by step process and building a dummy case from scratch in Petrel. NOTE: The values in this document are not the optimum and may cause convergence issues if the model was run based on them. You might need to modify them and make your own data (specifically Development Strategy section) to make the model run smoothly in ECLIPSE. 1

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Build a Dummy Model in Petrel from Scratch This document helps new users to get familiar with basic/fundamental yet essential functionalities by going through step by step process and building a dummy case from scratch in Petrel.

NOTE: The values in this document are not the optimum and may cause convergence issues if the model was run based on them. You might need to modify them and make your own data (specifically Development Strategy section) to make the model run smoothly in ECLIPSE.

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Bring all Useful Processes in Favorite Pane Favorite pane is a very useful and practical new functionality added to Petrel. It helps new and experienced users to have all the processes they need in one pane and just simply navigate through those processes. Beginners and users that use Petrel less frequently tend not to remember where to find a specific process and favorite will organize their frequently used processes handy. Also advanced users can benefit this functionality during presentation to higher manager where the simply follow the process tree that they have organized in favorite pane.

Here are the steps:

1. Open an empty Petrel project. 2. Save the project in a directory of your choice 3. From Menu bar go to Project>Project Settings and select Coordinate and units tab 4. Change Unit system and Simulation units in this tab and click on “OK”. I have selected Field.

5. If the Favorite pane is not visualized, from Menu bar go to View>Panes and select Favorite. You

should now be able to see Favorite pane. 6. Now go through the processes in Processes pane and Drag-&-Drop the ones that you use the

most in Favorite pane 7. In this case we need:

a. Make simple grid b. Make Horizons c. Make Zones d. Layering e. Geometrical modeling f. Make/edit polygons g. Make/edit surface h. Well completion design i. Make fluid model j. Make rock physics functions k. Fault analysis l. Make development strategy m. Make local grids

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n. Define well segmentation o. Define simulation case p. Pillar gridding q. Scale up structure r. Scale up properties

Note: From now on, I am calling each process from Favorite pane rather than Processes pane. This makes life easier and I don’t need to repeat Processes pane and each process-group header name (e.g. Simulation, Utilities etc.). For example instead of saying “open Make Simple Grid process from Processes pane, under Utilities” I’ll just say “Open Make Simple Grid”, since we know that all the processes that we are going to used are already in Favorite pane.

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Build a Simple Grid In this section we are going to build a very simple 3D model (11*11*11). We do not need to have any input at all. Our model will look like a box with no topography and later we can add simulation fault to it.

1. Open Make simple grid and give the new grid a name (I have called it Fine Grid). 2. Select Input data tab and fill the Top and Base limits as below. These are top and bottom of the

model we are creating (in this case 100 ft thick reservoir). Note: We do not have any data (here: Surfaces) available, hence we select Skeleton only option as below.

3. Click on Geometry tab and fill the boxes. This is the extent of your model in X and Y direction and you can input any value you want.

4. The result of this process is a new grid skeleton in Model pane. 5. Open a 3D or 2D window and visualize Top/Mid/Base skeleton of Fine Grid (Expand New

model>Expand Fine Grid>Expand Skeleton)

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We have the skeleton and areal gridding, now we should build the layers or vertical divisions of the model.

6. Right click on Skeleton and select Convert to surface. The result is Top/Mid/Base surfaces in Input pane as below. We need these surfaces to create horizons later on.

7. Open Make Horizons and append 3 lines as shown below and select and drop Top/Mid/Base surfaces that we just created in previous step (Input pane) into Input #1 in pop up window.

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We now have two horizons in our model and basically the reservoir is divided into two parts, upper and lower. You can visualize Horizons, Edges and intersections from Model pane in 3D window and see how your model look likes so far. By default we have two zones (upper and lower) and we now need to further sub-divide them into layers. We skip Make zones process and go straight to Layering.

8. Open Layering process and set each zone to 5, then we will have a model with 10 layers.

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The model is now ready to be populated by properties (PORO, PERM etc). If you look at the Edges, you can see that layering has been done correctly (10 layers). However, because the properties are not populated we cannot see the 3D grids yet.

9. Go to Model pane and right click on Properties and select Calculator. Here you can set PERM, PORO, NTG etc. Make sure you select a correct template for each property. Note that you can use Functions and Geometry options for some practical functionalities like Ran(Min, Max) that randomly distributes a property based on Min and Max value specified.

10. In 3D now you should be able to visualize PORO and PERMs under Properties.

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Add Simulation Grid Fault Since we have created a simple grid without using Pillar Gridding process, we do not have any geological Fault in the model. However, it is possible to add a simulation fault and assign a Transmissibility Multiplier (0-1) and use it in our simulation. Below are the steps to create these kind of faults:

1. Open 2D Window and visualize a 3D property. 2. Then create a polygon as below. To do this you’d need to activate Make/edit polygons and

select Start new set of polygons (deactivate old) button first and then draw the polygon.

3. Once the polygon is finished, it’s stored under the Input pane. 4. Right click on the polygon and select Create simulation (grid) fault:

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5. The result is a fault under New model>Fine Grid>Faults folder under Model pane with a vertical fault that cuts through the layers. You could rename the faults.

6. Open Fault analysis if you do not have Structural and fault analysis (RDR) license. And set the

multipliers, as below.

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Introduce Vertical Wells The 3D Grid is ready and now we want to add few vertical wells to the model as our producers/injectors.

Assume you know where you want to put the wells in. In our case here, I will introduce four producers at the corners and one injector in the middle. Therefore, I need to know what X and Y location of the wells are in my 3D Grid. I visualize the grid in 3D window and click on cells that I want to have the wells to be drilled and write down the X and Y values from Status bar. Here are my pairs: (150, 150), (150, 3150), (3150, 150), (3150, 3150) and (1650, 1650).

1. From Menu bar go to Insert and select New well. 2. Give the well a name (P1, P2, P3, P4 and IW1/IG1) to represent producer and Water/Gas

injector. 3. Input the X, Y and specify the Top and Bottom MD values.

The result is six wells introduced in Input pane under Wells folder.

There are no completion as of yet and wells can be used as they are, however they will be considered open whole. Here I will explain a quick way to add Casing and Perforation to the wells that later can be edited using well section.

1. Open Well completion design and select Create simple completions from Operation drop down menu

2. Drop the wells into Wells box 3. Deselect Create liner and Create completion string as below

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Now you can open Well Section window or Settings for each Completion (Casing/Perforation) and modify the Date and Intervals etc. I have modified the perforation to produce only from Oil zone (7020-7080 ft) and inject water only into Oil and Water interval (7020-7100 ft) and gas only in Gas Cap (7000-7020 ft).

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Build Fluid Model We now have the 3D model ready and well drilled where we want them. In order to initialize the model we need to have Fluid Model as well. Let’s imagine we have all three phases in this model. Below are the steps to create a representative fluid model:

1. Open Make fluid model and in General tab select Oil, Gas and Water under Phases section. Also input a Temperature and Reference pressure:

2. You may have noticed that by selecting Oil, Gas and Water, extra tabs are appeared in this window. Select a tab one at a time and see how they are empty. Select an appropriate fluid from presets examples (Use presets button) and this will automatically fill all required boxes in each tab, as below:

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3. Now it’s time to set the contacts and datum depth and its pressure. This is done using Initial conditions tab that is equivalent to EQUIL keyword in ECLIPSE. Please note that the depth in Petrel decreasing downwards, hence the depth values set here are to be Negative. In This case have set WOC = -7080 ft, GOC = Datum Depth = -7020 ft and Pressure a Datum Depth = 4500 psi.

4. The results is now stored in Input tab under Fluids folder. You could open a New Function Window and view Oil, Gas and Water properties as well as contacts and calculated pressure gradients.

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Saturation Function and Rock Physics To solve the fluid flow equations we need relative permeability and rock physics information. This is very simple to build in Petrel using presets data.

1. Open Make rock physics functions and go to Saturation tab. 2. Select Gas and Oil as phases and select Sand from Use presets drop down and click OK.

3. Go to compaction tab and select Consolidated sandstone from Use presets drop down and click OK.

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13. Now select POROSITY from Fine Grid model and drop it into this window. Then click on POROSITY and choose Algorithm an Averaging method (Averaging (volume weighted) and Arithmetic). Click Apply.

14. Now select and drop permeability from Fine Grid into this Upscaling property window. Then

select Permeability and choose Algorithm (Flow-based upscaling) and fill the settings and click OK.

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