Cmg gem manual

The black oil model is the simplest multi-component model which allows for mass transfer between the phases. The black oil model is based on the following assumptions: 1. The oil phase is considered to consist of two lumped components; a non-volatile oil component black oil or stock tank oil and a volatile gas component, gas or solution gas. The gas phase is considered to consist of only gas component 3. The water phase, w, is considered to consist only of water component.

Thermodynamics of reservoir fluid and fluid flow is taken care of in this simulator. Just three phases; oil, water, and gas.

Also it takes time to history match a case in GEM. If there is composition change between phase significantly you have to build your model in GEM. Petroleum Engineer University of Regina. IMEX is for black oil or dry gas reservoirs.

Senior reservoir engineer has used all of them and currently using GEM for their liquid rich shale play, Duvernay. Senior Reservoir Engineer Ph. Eng at Encana However, GEM cannot handle steam. Based on your reservoir and type of process you are applying you can use the appropriate software. There are some process which you can use two of those software but its depend on mechanism of the process. Thermal Reservoir Engineer at Husky Energy. Comments on geochemical reservoir simulation: CMG is being developed for variety of reservoir simulation purposes.

IMEX is used when you are simulating black oil model where there is no change in fluid composition or in some other situations. GEM is the compositional module that is applied when there is change in fluid composition such as CO2 flooding, asphaltene deposition, for condensate or volatile reservoirs.

Student at the University of Calgary. So if you have volatile oil and you want to run compositional simulation with thermal recovery option then go for CMG. If your reservoir is black oil then go for Schlumberger E software only. Reservoir Engineer, Consultant. Comments on geochemical reservoir simulation: IMEX is a black oil simulator with only gas-oil-water as components. Here Benefits 1. STARS also has the optional energy equation.

Comments on geochemical reservoir simulation: Note that IMEX has options which extend it's range of applicability, e. The K-value formulation runs faster than equation of state which requires numerous flash calculations. The suite of all three simulators allows you to handle pretty much every situation.

Comments on geochemical reservoir simulation: CMG reservoir simulation package is famous for its user friendly Builder interface. It is very simple to use and learn in comparison with other commercial software. Builder literally directs user through the modelling systematically without getting confused and miss something in your model. CMG offers three types of simulators i.

STARS has been designed for thermal simulation and vastly used in Canada for steam flooding in heavy oil recovery. CMG designed a very distinctive model known as MINC model which has primarily developed to account more correctly for connective heat flow from fracture to matrix in thermal simulation.

Comments on geochemical reservoir simulation: Recommend CMG software if simple interface and fast design of model is what you are looking for. He use Schlumberger's software i. CMG also is pioneer in unconventional shale gas modelling by allowing user to build very quick hydraulic fracture or SRV via its automated gridding feature Logarithmically Spaced LGR which is very convenient.

Student at University of Portsmouth. Comments on geochemical reservoir simulation: As real reservoir fluids consist of hundreds of chemical components. However, to limit the size of the computational system, components with similar chemical properties may be grouped into a pseudo component, treated as a single unity. With a black-oil fluid characterization model, the reservoir fluids other than water are assumed to consist of only two pseudo components, an oil component and a gas component.

With a compositional fluid characterization model, the number of pseudo components is in principle arbitrary. So, black oil simulator does the calculations quite easily as the fluid system is less complex than compositional fluid characterization model. However, if reservoir fluid composition varies significantly in the reservoir or injected fluid is different from the fluid already present in the reservoir, reliable simulation results can be only obtained with only a compositional model simulator.

It doesn't consider changes in the chemical composition of hydrocarbons as the field is produced. This tool is really very handy, good user interface and it gives good estimated results. Artificial Lift Systems Engineer, Weatherford Comments on geochemical reservoir simulation: Reservoir and production engineer only has experience in the use of IMEX. IMEX is a black oil simulator, you can also simulate gas reservoirs. STARS is useful to simulate process like chemical flooding, steam flooding, there you can manage a material balance for different components.

The interface with CMG is very friendly. The results are excellent, and is one of the most used reservoirs simulators worldwide. Comments on geochemical reservoir simulation: The choice of software depends on your application. Due to the coupled flexwell geo-mechanics it was easy to simulate near well bore changes due to stem assisted recovery. IMEX is more of a shale gas and naturally fractured formation simulator.

Due to its compositional nature it is great tool for improved oil recovery simulator. CMG software are all simulation tools. You would need a good geological modelling software as CMG is very good at importing the models. Field engineer- completion services Superior. This is used to simulate changes to the reservoir based upon fluid behavior, steam or air injection, electrical heating or chemical flooding.

According to your question, it's not adequate use one of these instead of other one. It depends of the kind of process to be simulated.

IMEX is used to obtain history-matches and forecasts of primary, secondary and enhanced or improved oil recovery processes where changing fluid composition and reservoir temperature are not important factors for accurate modelling of hydrocarbon recovery processes. This one could be used for non-miscible oil recovery process like water injection. Comments on geochemical reservoir simulation: GEM can model primary, secondary, and tertiary recovery processes, and accurately model complex heterogeneous faulted structures, horizontal and multilateral wells, and geomechanical deformation.

Petroleum engineer Former Weaterford All of the CMG simulators are relatively compatible they each will have cards specific to the application. We used IMEX for fairly simplistic models, but found the model construction and runs to be straight forward, and the runs were significantly faster than Eclipse or VIP, two of the major competitors. Reservoir engineer has used IMEX fairly extensively and it is the easiest simulator to learn on for black oil.

Reservoir Engineer, BP. For black oil simulation IMEX should be sufficient. It was just the software package that my company used at that time. But, when you start going in depth in IMEX the reservoir engineer ran into problem of depending too much to GUI, and the manual did not help that much in diving into keywords.

I don't have significant experience with those packages. Reservoir engineer Chevron. IMEX is a much easier simulator to use than Nexus, and more importantly, reduces the cycle time on decision making.

Additionally, Winprop, the fluid simulation from CMG, is easy to integrate within the entire simulation package. The user help manual and documentation is much more user friendly and understandable than Nexus.

Shell uses CMG. Don't know what the other operators use. We use Nexus. Reservoir Engineer, BP He is proficient with compositional simulation, recovery optimization, building grids and input data, importing and exporting data, interpreting data, modelling phase behavior and fluid properties, including transport phenomena and three-phase hysteresis for miscible EOR and uncertainty analysis and making production forecasts.

He has fewer experience with hystory matching and economic decision analysis, only basic knowledge of fratured reservoir modelling, basic knowledge of integrated reservoir and surface modelling, basic knowledge of polymer injection modelling and thermal processes modelling on STARS. Their group has been using CMG IMEX for the last 25 years, some of them are proficient in developing in house applications and in house simulators as well and are familiar with most aspects of black oil simulator conception.

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Download now. Related titles. Carousel Previous Carousel Next. Jump to Page. Search inside document. Nagwa Mansy. Min Yoongi. Benjamin Miranda Flores. Lauro Albano Jr. Click on the refined grid you want to remove. A highlight color default red rectangle will appear in or around the grid. NOTE: This edit operation applies only to the current layer.

If the refined grid extends throughout the entire range of layers in the grid, you will need to remove it from each layer individually. Splitting Grid Planes To split grid planes 1. Enter Edit Grid mode as described earlier. Split Grid Plane dialog appears.

To split planes in I plane select Split I Plane option. Repeat steps 2 and 3 for splitting along J rows and K layers. When you are finished modifying the grid, exit Grid Edit mode. It is recommended that you examine the well perforation locations, sector definitions and other features of the grid to ensure that the grid modifications have been performed as you expected.

Combining Layers Introduction Combining Layers or Up-layering is a technique that provides engineer with optimal geologic layer-grouping schemes for simulation model construction. It will reduce many often hundreds geologic fine layers to much less coarse simulation layers and yet try to maintain the heterogeneity of the reservoir in the K vertical direction.

The grouping of the layers can be done manually or automatically in the Builder. When in manual mode, the Builder provides the user with average and standard deviation of the guide property to help the user to decide which layers to combine. The guide property is typically porosity, K direction permeability or combination of both.

When in automatic mode, the Builder can suggest the optimal combination of the layers given the desired number of simulation layers. A table of residues the difference of the defined property between the finelayer and coarse-layer models is produced from exhaustive analysis of all possible layering combinations.

Using this table, engineers can determine the desired number of simulation layers needed based on their tolerance of possible loss of fine-layer geologic features. Note that all refined grid blocks will be deleted during the combining operation. These may be manually added back after the combining is complete. Well perforations, sectors, aquifers and lease planes will be preserved during combining.

To start the Uplayer Wizard: 1. You must be in Edit Grid mode to start the Uplayer Wizard. A Grid Editing Options dialog box will pop up. Select Editing limited to the default and click OK. You are now in grid edit mode. Uplayer Wizard The first page of the 3-page Uplayer wizard is as follows:. The default mode is set to Let the Builder recommend the layers to combine. The default guide property Guide property for grouping layers is set to permeability K divided by porosity if both properties have values in the current model.

If only one of porosity or permeability K is available, then the default will be whichever is available. Other properties may be used as the guide property also, though less common. If the geological unit associated with each grid layer is available as when the grid was directly imported from a RESCUE model , then the option Honor all geological unit boundaries will be available. If you check this option, then the Builder will not combine layers from two different geological units when searching for the optimal combination scheme.

You can control the weight of standard deviation term in computing the residue by changing the slider value. Refer to the above SPE paper for more detailed information.

Click the Start button will start the computation of minimum residues for all possible layer grouping schemes. Note that this will take tens of seconds to tens of minutes to complete, depending on the number of layers and number of blocks in the model and the CPU power of you computer. There will be a progress bar with a Cancel button to show the percent of completion and allow cancellation of the operation. Once the table of minimum residues for all possible layer combinations is generated, you can decide on the number of the desired simulation layers based on the information in the table.

The residue values in column two are normalized. They are the square root of the residues as defined in the SPE paper divided by the average property value for the whole reservoir. If you wish to preserve all reservoir heterogeneity, then choose the lowest number of layers with residue of zero. Click a row in the table will update the number in the Desired number of layers edit box. Click Next to get to the second page. Example showing residue table after calculation:. If you have chosen I will choose layers to combine option, you only have to select a Guide property for grouping layers and click Next to get to the second page.

The second page looks like the follows if you are in automatic mode:. The suggested new layer combination scheme is displayed in the column New Layer. Normally, you do not have to adjust anything because the displayed layer scheme is the optimal one, given the desired number of simulation layers.

You can click Next button to go to the next page. If manual mode has been chosen earlier, the New Layer column will be identical to Old Layer column as a starting point. The arithmetic average and standard deviation of the selected uplayer property, along with porosity and permeability K, are displayed. You enter the new layer numbers based on the given information. If you enter a new layer at certain row, the whole New Layer column will be adjusted. To combine several layers, you drag and select a range of rows at New Layer column and then click on the Combine Selected Layers button or right click and select Combine Selected Layers from the context menu.

Once you are satisfied with the new layer combination scheme, click Next to bring up page 3 of the wizard. This page contains the table of property names and averaging methods to be used for the properties. Initially, the default method is displayed for each property. You can change the average method by clicking in the Average Method column.

A list of the available methods will be displayed. There are seven methods available: 1. Pore Volume Weighted Arithmetic 2. Pore Volume Weighted Harmonic 3. Pore Volume Weighted Geometric 4. Gross Volume Weighted Arithmetic include null 5. Gross Volume Weighted Harmonic include null 6. Gross Volume Weighted Geometric include null 7. Gross Volume Weighted Arithmetic exclude null Null block volumes are included in the gross volume computation and property values are assigned zero for null blocks in average methods Null blocks are excluded in the average calculation in method 7, which is suitable for properties such as temperature.

Volume Weighted Harmonic average method should be used for K direction properties, such as permeability K and Transmissibility Multiplier K etc. Geometric properties, such as grid top, bottom, thickness and net pay etc. The values of integer properties for combined blocks are based on the volume majority rule. That is, the combined blocks are assigned the integer value with the greatest volume. Once appropriate average methods are chosen for each property, click Finish to start the uplayering process.

There is no undo for this operation. If you do not like the results of uplayering and want to try a different layer combination scheme, you have to re-read the original dataset and start the uplayer wizard again.

When the uplayering is done, exit Grid Edit mode. It is recommended that you examine the well perforation locations, sector definitions, aquifer and lease plane locations to ensure that the grid modifications have been performed as you expected. Extracting a Sub-section of a Grid To extract a sub-section of a grid: 1.

Extract Grid Submodel dialog appears. Alter the beginning and ending I-, J-, and K- from and to sliders until the desired sub-section of the grid is highlighted.

NOTE: There is no Undo for this operation, because of the potentially large memory required to back up the grid and all the properties. Editing a Cartesian, Radial or Orthogonal Grid 1. Enter the Edit Grid mode as described earlier. The grid rotation, translation, grid line editing and grid refinement operations are described in Creating a Simulation Grid Using Structure Maps.

When done, click the Probe Mode button on the modes toolbar to exit Edit Grid mode. This puts you in last stage of the non-orthogonal corner point grid creation wizard. You can add grid block refinement at this stage without destroying the property and well data. If you only intended to add refinement, click Finish. If you want to modify the control points, click on the Prev button.

A message warning that if you proceed further all your property and well data will be destroyed comes up. If you only intended to add refinement, choose the first option in the Grid editing options dialog box that comes up on entering Edit Grid mode. Proceed as described in Adding and Removing Refined Grids. Select one of the options and click OK. Specifying, Calculating and Adjusting Structure and Rock Property Values Once you have finished creating or modifying your simulation grid, you can specify how to assign, calculate, or interpolate values for structural and rock properties for each grid block.

After you have specified how to calculate one or more properties, you tell Builder to do the calculations. After the calculations are complete, the calculated property values can be displayed and modified. Properties may be assigned by layer or region , interpolated from maps, imported from a RESCUE model, or calculated using geostatistical routines. Builder has a number of map creation and geostatistical routines available see the Chapter Creating Maps and Geostatistical Properties which are available via Create map under the File menu, and Geostatistics under the Reservoir menu.

Specifying Property Interpolations and Calculations To specify a property calculation: 1. You must be in Probe Mode to perform this operation.

To enter Probe Mode, select Probe Mode from the mode selection box, or right click to pop up the context menu and select Probe Mode by left clicking on it. The General Property Specification dialog box appears:. The dialog lists the property names in columns and the simulation layers in rows. Whole Grid, which indicates an identical specification for all the layers, is also included. Also displayed are the units of the property. Enter specifications for the property.

Use the Go To Property combo box to select the property. This will bring the property column in the view. Or use the scroll bar at the bottom to bring the column in view. If you want to specify a constant property for a layer, simply type in the value. You can also use the Cut, Copy and Paste commands on the context menu right click in a cell to delete, move or copy a specification from one cell to one or more cells.

These and other menu items appearing on the context menu are also available in the Edit Specification menu at the top of the dialog. Note: Copy and Paste from Excel can also be done. This is restricted to numerical values only and only a single column at a time. If multiple columns are selected only the first column will be pasted. The Property Specification dialog box opens up.

For Constant, enter a single value to be applied to all grid blocks in the selected region. For Contour map, click on the Values in file 1 button and an Open dialog box will appear. Select the first map file.

If you wish to calculate the property as a difference between values from two maps, specify the second map file. Enter a multiplier applied to interpolated values in the times text box. For From Formula, see the section on Using the Array Property Calculator to learn how to create formulae to calculate one array property from one or more previously calculated array properties. This option is enabled only if at least one formula is defined. Select the averaging method from the Average Method drop-down list box.

The Regions Property Specification dialog appears. Select the property to be specified from the Select property: list. The left column of the property list will contain one of the following codes: If you see Neither specified nor interpolated Both specified and interpolated Specified only Values only not specified.

Select regions to be specified by clicking on a region in the Regions List, then clicking on Add to region list. Regions can be the whole grid, individual layers in the grid, sectors, or PVT and rock type regions.

Once you have added regions to the Region List, you can re-order the list using the Order buttons. The calculations are done in the order of the list. If a grid block is in two regions, a value calculated in a later region calculation will override the earlier calculation done in the first region.

Next, specify how to calculate each region. The Property Specification dialog appears: Follow steps 7 12 to input a specification. Select the next region and perform steps 6 through Continue until all regions are specified. You can select and specify additional properties. When you have specified all the properties you want to at this time, click OK to apply the specifications, or Cancel.

NOTES: Grid Thickness You can define grid thickness as the difference between interpolated values of two contour maps times a multiplier. For example, you may wish to divide a single geological layer into two or more simulation layers.

If you only have contour maps for the top and bottom of the geological layer, you can specify the thickness of each simulation layer as a fraction of the distance between two contour maps. In this case, select on map for Values in file 1 and the second map for Values in file 2. Layers that you do not specify are stacked below or above the specified layers. If you have not specified the top most layers, these layers will stack above the specified layers.

Multipliers The multiplier, specified in the times text box, has several possible uses. As previously mentioned, it can be used to divide a single geological layer thickness over several simulation layers.

It can also be used to do unit conversion. For example, the simulators expect porosity to be expressed as a fraction. If your contour map has porosity as a percentage, you can multiply by 0.

Finally, if you have an elevation map Z direction measured positive upwards you can convert this to a depth map Z direction measured positive downwards by multiplying by 1. To specify NULL block calculations: 1.

NULL block specification is similar to other property specification, described above, except for the dialog used to specify each layer or region:.

Select one of the radio button options for the specification. You may also need to enter a cut-off value for some of the specifications. Click OK to save the specification, or Cancel. Performing Interpolations and Calculations After you have specified one or more properties, you can tell Builder to perform the calculations.

You do not need to specify all the properties at one time. Rather, if you wish, you can specify and calculate the properties one at a time. To perform interpolations and calculations: 1. At the top is a list of all the properties that you have specified. Properties that need to be calculated are indicated with a check mark. You can force the recalculation of a specified property or defer the calculation of a property by checking or unchecking individual properties.

You can check individual regions to calculate only specific regions for a property. For example, if you have specified a property with a map interpolation for each grid layer, and you receive a new map for one particular layer, you can specify that only that layer be recalculated. In Property Values in Refined Blocks, select either Use property value in parent block or Interpolate from contour maps. Note that structural properties Grid Top and Grid Thickness always use the parent block values to determine refined block values.

Interpolate from contour maps only applies to rock properties such as porosity or permeability. Occasionally, the interpolation routine is unable to interpolate a value for a grid block because there are no nearby contour lines, the interpolation point is surrounded by faults, or all the mesh points in the vicinity are set to the NULLFLAG value. If this occurs when interpolating the Grid Top property, the top value at the interpolation point is set to zero.

Click OK to begin the calculation, or Cancel. While the interpolation and calculation is being done, status messages will appear on the status bar at the bottom of the main Builder window indicating progress. Once the property calculation is complete, one of the calculated properties will be displayed in view. To change the view settings and content, see the chapter on Changing Display Contents and Settings. Deleting a Property If you wish, you may delete a calculated or imported property.

From the Reservoir menu, select Delete Properties The Delete Properties dialog will pop up with a list of the calculated properties not including structural properties like Grid Top and Grid Thickness. Select a property or properties to delete, and click OK. Importing Spatial Properties You can import spatial properties in a number of ways: 1. Import the properties along with the simulation grid from files output by geological packages refer to Importing 3D Simulation Grids and Grid Properties in this manual.

Import properties from CMG dataset files without importing the grid. Import properties from a text file containing an array of values. The Import spatial properties dialog is displayed. The importable properties in the source file are listed in the list on the left. Select a property name from the list on the right. Click Add to Selected List button. The source property will be imported as the property you specified in the list on the right.

Values will be converted to account for different unit systems in the two dataset files. Properties will not be imported unless the numbers of fundamental blocks in the two files are identical. If the target dataset has local grid refinement but the source dataset does not, only the fundamental grid block values will be imported and the refined blocks inherit from the parent blocks. If both the datasets have local grid refinement, the refined block values are imported only if the total numbers of grid blocks fundamental and the refined in the two files are identical.

Builder does not validate the location and size of each refined grid, i. A property may be listed a number of times if it was output more than once in the simulation output file.

This selection enables you to initialize a property with values at times later than the zero time from another simulation run. If the file contains more than one value array, each array should begin with a keyword. The keyword could be a valid array keyword but is not required to be so. A grid must be defined in the current dataset. From the File menu select Import from another file and then Spatial properties from stand-alone arrays. Values are assumed to be in Builders current unit system.

If the target dataset has local grid refinement but the source file does not, only the fundamental grid block values will be imported and the refined blocks inherit from the parent blocks.

If both have local grid refinement, the refined block values are imported only if the total numbers of grid blocks fundamental and the refined in the two files are identical.

A geological unit is defined as a group of contiguous grid layers all belonging to the same geological formation or reservoir unit. A geological formation is typically bounded by a top and a bottom geological surface.

In such a case, the grid layers included between the top and bottom surface will form a natural definition. In any case, one should strive for homogeneity when defining a geological unit. Using geological units is a way to avoid mixing very different data when using the geostatistical methods.

To define Geological Units: 1. Select Geological Units under Reservoir menu. The following dialog will appear. If the geological units are defined, the dialog will show the current definition as in the example above.

If no geological units are defined, the dialog will show only one unit including all grid layers. By default, all layers belong to the same geological unit. Select the Number of geological units with the spin box. The number of geological units that can be defined is limited between 1 and N where N is the total number of grid layers. The geological units must be contiguous, non-overlapping, and no gaps are allowed. Each grid layer must belong to one and only one geological unit.

The dialog is designed to enforce those rules. The From Layer cell of the first geological unit is always 1 and cannot be edited. Similarly, the From Layer cell for all other geological units cannot be edited. The To Layer cell of the last geological unit cannot be edited. It is always defined as N, the total number of grid layers.

The Unit Name can be changed at will. Click the OK button to save the newly defined geological units. The Cancel button allows you leave the dialog without saving. A dialog will appear asking you to select the dual porosity option to use. Click OK to perform the conversion. After the conversion is done, you will need to specify and calculate grid properties for the fractures, as well as enter other required data.

Pinching Out Thin Grid Blocks Very thin grid blocks may slow down a simulation run, while only containing an extremely small fraction of the total reservoir volume. You can pinch-out grid blocks remove them from the active simulation grid, while maintaining reservoir flow in a vertical direction through the blocks.

By default, only extremely thin grid blocks are pinched out thickness less than 1. To automatically pinch-out thin reservoir blocks: From the Reservoir menu, select Block Pinch-out thickness setting. The Set pinchout thickness dialog will appear. Enter a new value for the pinchout thickness and click OK. Builder will mark all blocks less the specified thickness as pinchout blocks.

Fixing Overlapping Blocks Whenever the grid structure is changed by an interpolation, the grid is checked to see if grid blocks overlap. Such an overlap could occur if the contour data for two grid tops and the thickness of the layer s in between are not consistent. For example, the map you give for Grid Top in layer 1 may, at points, dip below the map you give for Grid Top of layer 3.

Builder includes a feature that allows you to select the grid depth specification property and layer that you consider most reliable and to fix the grid block overlap based on this map.

The property and layer indicated as the most reliable data will be left unaltered, and other properties will be adjusted to eliminate grid block overlap. For each column of overlap, Builder will first fix the location of the block in the selected layer using the selected depth property specification, and then alter the depths of other blocks in the column by adding or subtracting the grid block thickness.

To fix grid block overlap: 1. Select Fix Grid Block overlap from the Reservoir menu. The Fix Grid Block overlap dialog box appears:. Select the property that you consider most reliable i. Click on OK to apply the fix, or Cancel. If the net pay is greater than the gross pay in any grid block, a message box will pop up and inform you. To fix net-to-gross ratio problems: 1. Select Fix Net-to-Gross ratio from the Reservoir menu.