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Conventional multi-well model

With the conventional multi-well (CMW) model, you can simulate multiple wells using the group numerical model to history-match producing wells and forecast future production.

Note:

This model works with your Harmony Reservoir™ license.

Before you start using the multi-well model, make sure that all required information is added to the Harmony Enterprise project:

Populate sandface locations for each well in the Attributes tab.
Populate well production data (rates and sandface pressures) in the Production editor for each well in the group.
Specify reservoir and fluid properties in the Properties editor of the group. When you create a new multi-well model, group reservoir properties are automatically applied.
Populating wellbore information (such as, a deviation survey, completion, and perforation data) is not required. However, we recommend populating this information because it helps to initiate the multi-well model with correct default settings.

We recommend that you perform analyses and/or modeling for individual wells prior to using the multi-well model. You can bring in parameters from individual well analyses as a starting point for the multi-well model. Additionally, you can perform certain group analyses. For example, a flowing material balance (FMB) performed on the group gives an estimate for original fluid in-place for the reservoir.

By default, the Plots tab opens (with the Wells button selected) with a dashboard with four plots. For more information, see dashboard.

Model creation

To create an CMW model:

1. Create a group (in the Entity Viewer - Hierarchy or Entity Viewer - Custom) that contains all the wells you want to include in the model.

2. Launch the group for analysis. For more information, see selecting an entity for analysis.

3. Click the Group image and select Multiphase Multi-well Model, Conventional.

You can create a Black Oil or a Gas Condensate model:

Black Oil — accounts for gas dissolved in liquid, but does not account for liquid vaporized in gas; therefore, you should not create a Black Oil model for a group that has liquid-rich gas as a gas type.
Gas Condensate — used to create a multiphase model that accounts for liquid vaporized in gas. This model should only be used for groups that have liquid-rich gas as their gas type.
Volatile Oil — used to create a multiphase model that accounts for liquid vaporized in gas. The water phase can be turned off within the model..

Note: For more information, see modifications for the multiphase model.

Model geometry

This analysis currently supports vertical, vertical with fracture, and horizontal well completions. Wells are placed in the reservoir according to their actual locations (specified by sandface lat / long in the Attributes tab). Length and direction of horizontal wellbores are drawn according to L_e and Azimuth parameters.

Reservoir boundaries default to 1,320 ft (a 1/4 section) from the outermost wells. These boundaries can be adjusted using the and icons. For more information, see the Schematic plot toolbar description.

This is a reservoir with well regions:

These are vertical wells with cell regions:

This is a horizontal well with cell regions:

Setting model parameters

Well regions are automatically created for the model by drawing boundaries halfway between adjacent wells. These regions are used for setting parameters, such as net pay and permeability in the grid cells of each region. They do not represent no-flow boundaries.

To specify the properties for each region, select the well by clicking it in the schematic, or select the well from the drop-down menu, or use the arrows in the primary toolbar. When you click the Wells button, you can manually enter properties, or click the Pull Defaults icon in the primary toolbar to use values from analyses in the well.

The initial pressure, bubble-point pressure, compressibility, and area are specified in Reservoir, and are applied to the entire reservoir. If you have the Properties editor populated for the group before creating the Multi-well model, this information is pre-populated when the worksheet is created.

Primary toolbar

The primary toolbar has the following icons:

Pull Defaults — select from these options:
- Group Properties — copies default values from the Properties editor of the group.
- Selected Well Properties — copies default values from Properties editor of the selected well.
- Group Analysis — displays a sub-menu with all the other multi-well analyses for the group. (If there are no other multi-well analyses, this option is not displayed.) Selecting one of the existing analyses copies one multi-well analysis to another in the same group, which can be useful if you want to experiment with the copy of the analysis while preserving the original content. Note that the parameters on the Forecast tab are not copied.
- Selected Well Analysis — displays a sub-menu with all the analyses (that is, typecurve, analytical, and numerical) for the selected well. (If there are no other analyses, this option is not displayed.) Selecting one of the existing analyses, copies parameters of that analysis to the currently selected well.
- Another Well in this Model — displays a sub-menu with all the other wells in the same model. Select one of the wells to copy the calculation method, well parameters, and constraints from that well to the currently selected well (displayed in Wells under Selected Well).
Push Defaults — pushes well parameters, calculation method, and constraints from the currently selected well to the wells you select from the drop-down list.
Synthesize — click this icon every time you want to history-match and create a forecast.
Stop Synthesize — stops the model's synthesize calculations.
Previous Well — jumps to the previous well.
Next Well — jumps to the next consecutive well.

Copy to / Paste from Clipboard — copies / pastes entity parameters from the clipboard.
Playback icons ()

After you click the Synthesize icon ( Synthesize icon ) in the primary toolbar and the calculations are complete, the icons listed below are enabled in the same toolbar. With these playback icons, you can see how pressures or saturations change through time. A tooltip displays the pressure or saturation value and unit, as you hover over your color-shading plot.

Skip to Beginning — displays the first timestep.
Step Back One Frame — view timesteps in reverse one frame at a time.
Play in Reverse — view timesteps in reverse. You can click this icon multiple times to increase the speed of the playback.
Stop — stops the playback process. As you hover over various cells in your well, the pressure or saturation is displayed.
Play — view timesteps from start-to-finish. You can click this icon multiple times to increase the speed of the playback.
Step Forward One Frame — view one frame at a time.
Skip to End — displays the last timestep.

Plots tab

This tab displays four plots in a dashboard and has two buttons in the lower left: Wells and Reservoir.

Tip:

If the dashboard is blank, you need to provide well locations (latitude / longitude) for your wells. You can enter these latitudes and longitudes in the Attributes tab, Location node.

Wells

When you click the Wells button, you can specify model parameters on a per-well basis.

These items apply to Wells:

Selected Well drop-down list — select the well you want to modify within your multi-well group.
Include — by default, all wells in the group are included in the model. Deselect Include to exclude the selected well from the model (it is modeled as a shut-in well). If the well is excluded, you still need to set up valid parameters for it; the geometry of the well region is still being used to generate a grid used in the model. However, if the well is excluded, its production is not taken into account, and permeability for the whole well region (including fracture and SRV) is modeled to be equal to the matrix permeability (k_matrix).
Completion Type drop-down list — select either Vertical, Horizontal, Vertical with Fracture.
If you select Horizontal, two parameters are displayed:
- k — permeability
- s_f — damage skin on fracture face

If you select Horizontal, two parameters are displayed:
- Le — type your effective horizontal well length, or accept the default values from your perforation data in the Wellbore editor by clicking the Pull Defaults icon () in the primary toolbar. (You can accept wellbore data from the reservoir or an analysis.)
- Azimuth — is the angle between North and the wellbore. Type your value in degrees, or click the Pull Defaults icon to use the default values from your deviation-survey data in the Wellbore editor (as long as you have easting and northing data).
- In addition, two permeabilities must be entered: k_xy (permeability in the horizontal direction) and k_z / k_zy (permeability ratio).

If you select Vertical with Fracture, six parameters are displayed:
- k — permeability
- x_f — fracture half length
- F_CD — dimensionless fracture conductivity
- k_fw_f — fracture conductivity
- Azimuth— is the angle between North and the wellbore. Type your value in degrees, or click the Pull Defaults icon to use the default values from your deviation-survey data in the Wellbore editor (as long as you have easting and northing data).
- s_f — damage skin on fracture face
Calculation Method for Production — set if the selected well is to be operated at rate, or at pressure control.
Calculation Method for Injection — if you have injection rates for your well in the Production editor, the Calculation Method for Injection section is enabled, and you can set controls to be used during injection.

Reservoir

When you click the Reservoir button, you can specify parameters that are used for the entire reservoir model.

Fluid type selection

Click the checkboxes for the fluid phases you want to include in your model: Gas, Oil (or Condensate), and/or Water.

Aquifer

In the Aquifer section, you can have an aquifer edge, bottom, or both. In order to account for an aquifer in your reservoir, you need to connect it. For more information, see the Connect Aquifer icon description.

If you select Edge Aquifer, you must specify values for OWIP_E∆q and k_E∆q.

If you select Bottom Aquifer, you must specify values for OWIP_B∆q and k_B∆q.

Volumes

When you click the Volumes button, read-only values for Reservoir are displayed.

Options

When you click the Options button, various gridding parameters are displayed. After you set your reservoir dimensions, well locations, and well completion parameters, the CMW model creates an appropriate grid to get accurate results with minimal calculation time. To display gridding, right-click the schematic plot and select Show Grid Cells.

Usually, the default gridding settings are fine, but in some cases, you may want to adjust the gridding parameters. Gridding parameters are as follows:

Ratio_nwb — controls the size of the cells adjoining wellbores and fractures.
Ratio — controls the rate at which cell sizes increase as they go further from the completion.
n_sectors — the number of sectors used for the radial portion of the gridding. In the figure above, n_sectors = 4, so each half-circle is divided into four sectors.
n_fracture — the fracture has one wellbore cell in the middle, and each wing of the fracture is divided into n_fracture equal parts.
n_HzWb — the horizontal wellbore is divided into n_HzWb equal parts.
n_decrease — the row of cells adjoining the completion is divided into equal cells. The number of cells is equal to 2 * n_fracture for fracture completions and is equal to n_HzWb for horizontal completions. For each subsequent row, the number of cells decrease by n_decrease.

Dashboard

In the dashboard, there are four plots, which are described below.

Schematic plot

This plot displays a schematic view of the reservoir shape and the location of the wells within it, as per their sandface latitudes and longitudes. You can edit / rotate your reservoir, display shapefiles, view / edit your aquifer, and view shaded plots while you run a simulation.

These toolbar icons are unique to this plot:

Edit Reservoir Boundary — click-and-drag to move your reservoir. Scroll your mouse wheel to expand or shrink your reservoir. White circles move an entire edge of the reservoir boundary. Red squares move only the selected vertex. Click a mid-section of a reservoir edge to add a new red vertex; note that your cursor changes to a cross.

Rotate Reservoir — scroll your mouse wheel, or use your keyboard's arrow keys to rotate the boundaries of your reservoir (the physical location does not change) around the reservoir center. To rotate your reservoir around your cursor, press the Ctrl key and scroll / use your arrow keys.

Display Shapefile — display the shapefile you have in the GIS tab in the multi-well model. If you do not have a shapefile, this icon is grayed-out.

Undo — undoes your last action. (You cannot undo your zoom as this icon applies to resizing only.)

Redo — reapplies the size of your reservoir to your previous settings. (You cannot redo your zoom as this icon applies to resizing only.)

Reset Reservoir Boundary — resets your reservoir size to the default setting.

Connect Aquifer — this icon is available if Edge Aquifer or Bottom Aquifer are selected in Reservoir. Click this icon to set the parts of the reservoir boundary that are connected to the edge or bottom of the aquifer. Segments of the boundary that are highlighted in blue are connected to the edge of the aquifer. By default, the entire reservoir boundary is connected to the aquifer, but you can select and deselect edges by clicking them. Cells that are highlighted in blue are connected to the bottom of the aquifer. (The mouse cursor becomes blue when you are in connect-aquifer-selection mode.) You can also select Connect All to Aquifer or Deselect All from Aquifer for your cell regions by right-clicking the schematic.

Shaded Plot Display Mode — this drop-down list becomes available after the model has been synthesized. Use this drop-down list to select which property you want to display in each grid cell. You can select one of the following properties to display it: Pressure, Saturations (color scheme based on saturations of all three phases), Gas Saturation, Oil Saturation, Water Saturation, Permeability, Net Pay, or Porosity.

For information on common plot icons, see plot toolbars.

After you click the Synthesize icon ( Synthesize icon ) in the primary toolbar, the synthesis proceeds. Position lines are displayed to indicate calculation progress. The shaded plot displays the distribution of pressure or saturation at the timestep that has just been calculated (as indicated by the time-stamp in the lower left corner, which displays the exact date and time). After the calculation is completed, these Position lines can be dragged to the moment in time you want to examine more closely, and all plots are synchronized.

If you find that the color scale for your shaded plot needs adjusting, right-click the legend and select Customize Color Scale, and then type customized min and max values. To revert back to the default min and max values, right-click the legend and select Reset Color Scale.

Note:

After you click the Shaded Plot Display Mode drop-down list and select an option, you can view values for each cell region by hovering over the shaded plot. Tooltips are displayed for each cell region.

Context menu

Right-clicking the reservoir view for your wells lists these options:

Reservoir Region — show / hide the reservoir boundary.
Wells — show / hide the wells in the reservoir.
Well Names — show / hide the well names in the reservoir.
Well Regions — show / hide the boundaries of the well regions.
Cell Regions — show / hide the grid cell boundaries for each well in the reservoir.
Selected Well — show / hide the well name for the selected well.
Scale Gridline — show / hide gridlines with a scale marker.
Connect All to Aquifer — when Bottom Aquifer has been selected in the Aquifer section of Reservoir and you are in aquifer-selection mode, you can select all of the cell regions at once by selecting this option.
Disconnect All from Aquifer — when Bottom Aquifer has been selected in the Aquifer section of Reservoir and you are in aquifer-selection mode, you can deselect all of the cell regions at once by selecting this option.
Copy Lat / Long to Clipboard — copies the latitude and longitude of the current position of the mouse pointer. These latitude / longitude values can be used to add a new infill well at the location you want:
- Move the mouse pointer to the location for the new infill well; then, right-click and select Copy Lat / Long to Clipboard.
- Create a new well using the Entity Viewer - Hierarchy. For more information, see adding an entity.
- Open the Attributes tab for this well and paste the surface latitude and longitude from the clipboard.
- Add this new well to the multi-well group previously used to run the multi-well analysis. (You can drag-and-drop the new well from the Entity Viewer - Hierarchy to the Entity Viewer - Custom.)

Ratios plot

This plot displays historical and simulated ratios for the selected well. For a description of its common icons, see toolbars.

Well Rate Time plot

This plot displays historical and simulated rates and pressure for a single well. To switch wells, you can:

Click the arrows in the main toolbar.
Click a well in the schematic plot.
Select a different well from the Select Well drop-down list.

For a description of its common icons, see toolbars.

Total Rate / Cum Time plot

This plot displays the total historical and simulated rates / cumulative production for the entire reservoir and the reservoir pressure. This plot has one unique toolbar icon:

/ Switch to Rate vs Time / Switch to Cumulative vs Time — toggle between these two views. (Only available on the Reservoir Rate vs Time plot, not on individual well plots.)

Forecast tab

This tab has the same features as the numerical Forecast sub-tab, but you have the option to display all wells in the group, or individual wells.

Forecast Plot

If All Wells is selected in the Select Well drop-down list, the Forecast plot displays group-level rates and reservoir pressures. If one of the wells is selected in the Select Well drop-down list, the Forecast plot displays rates and flowing pressures for that selected well.

Forecast Options

Use the Select Well drop-down list to pick any individual well or All Wells. Select one of the wells to see forecast settings for just that well in the Forecast table, or select All Wells to see forecast settings for all the wells together.

The Forecast Start Date is set for the entire model (the forecast for all the wells starts at this given date).

The values in the Duration column are shared between all the wells in the model.

Forecast Constraints are applied for all of the wells in the model.

After you set up a valid forecast and synthesize it, the Forecast Results table displays EUR, RR, and historical volumes for each well for each of the fluid phases available in the model.

Forecast Injection

To forecast injection for any well, select one of these options from the Control Type drop-down list:

Gas Inj Rate — the forecast at a given gas injection rate.
Water Inj Rate — the forecast at a given water injection rate.
Pressure (Inj Gas) — the forecast at a given sandface flowing pressure. (This pressure is reached by injecting gas.)
Pressure (Inj Water) — the forecast at a given sandface flowing pressure. (This pressure is reached by injecting water.)

Note:

In order for the above options to be available, the corresponding fluid phase must be selected when you click the Reservoir button.

Injection constraints are applicable when at least one of the wells has an injection forecast.

(p_inj)_max — sets a maximum sandface flowing pressure during the forecast. In order to maintain the maximum flowing pressure, the injection rate is adjusted.
(q_ginj)_max — sets a maximum gas injection rate during the forecast. In order to maintain the maximum rate constraint, flowing pressure is adjusted.
(q_winj)_max — sets a maximum water injection rate during the forecast. In order to maintain the maximum rate constraint, flowing pressure is adjusted.

Toolbar

This toolbar has the same common icons described in plot toolbars.

Tables tab

This tab displays synthesis data for your wells in three sub-tabs: <well name>, Total, and Run.