Navigation:  Numerical Modeling Workflow - Finite Difference Grids > Define Boundary Conditions >

Wells

Print this Topic Previous page Return to chapter overview Next page

Pumping Wells

 

Visual MODFLOW Flex provides an improved approach and interface for working with pumping wells in the conceptual and numerical model.  Visual MODFLOW Flex follows a logical approach of defining the well rate over the entire well, and independent of the numerical grid. With this "conceptual" approach, a single well can contain multiple screens, fully penetrating screens, or partially penetrating screen intervals over the depth of the wellbore. Pumping wells are defined at X,Y co-ordinates, and not assigned to specific grid cells. This provides flexibility in changing the numerical grid and the ability to readily use well locations (points) as grid node generators for MODFLOW-USG.

 

Pumping well data are shared between the conceptual and numerical models so that modifications to the conceptual model will translate into the numerical model. Pumping wells are presented in an easy-to-use view showing the well location, screen geometry, and pumping rates. Since the rate is assigned to the entire well, you don’t need to worry about figuring out how much discharge is proportioned to each model layer; Visual MODFLOW Flex does this calculation for you automatically.  For details on how well rates are calculated for the .WEL package, see the section Calculation of Well Rates

 

In addition, if you are running a transport simulation, point source concentrations for an injection well are defined/edited on a per well level, an approach that more closely represents actual field conditions.

 

Further improvements to wells that will enhance the “ease-of-use” include:

Import pumping schedule data in relative times (starting at 0 days), in addition to absolute dates (eg. 04/22/2015)

Setting individual wells as active/inactive in the database view, and having this setting translated to the .WEL package

Adding one or more new wells with the click of a mouse

Enhanced visualization of the well screen in cross-section view (by row/column), and in 3D view

Flexible labeling and rendering options in 2D and 3D.

Display the well name in the .WEL package, to correlate the conceptual well to a specific MODFLOW grid cell.

 

Working With Wells in Projects Prior to v.2015.1

 

Visual MODFLOW Flex is backwards compatible with projects made in v.2014.2 and older. When you open such a project that contains pumping wells in the numerical model, and try to edit a well cell, you will see the following window:

 

 

You may proceed with editing the well rates/schedule for wells in the numerical model.  However, you are strongly encouraged to convert wells in this old (cell-based) format into the new wells (conceptual object) format. The benefits of working with the new (conceptual) wells are the following:

 

more logical editing of the well rates/schedule defined over the screen interval (as opposed to defining rates for individual cells)

improved display of the wells (in the conceptual model and numerical model, in 3D, layer and cross-section view)

robust translation: accommodate multiple wells in the same cell, with individual entries in the .WEL package

option to set individual wells as active or inactive for the simulation.

simple option to point-and-click to create a well in the numerical model

 

The process of conversion is described below.

 

Converting From A Cell-Based (Old) Wells Object To Conceptual (New) Wells Object

 

Before You Start!

The conversion process will involve deleting the wells in the numerical model and conceptual model and creating a new wells object utilizing the "raw wells" object (from the Data tree). If you have done cell-based editing of well rates in the numerical model, these edits will be lost. In addition, if you have assigned point source concentrations to wells in the numerical model (for a transport scenario), these changes will also be lost (you will need to re-assign these parameters after creating the new wells object).

 

If you have made significant edits to well rates/schedules in the numerical model, then you may wish to avoid this conversion.

 

Before proceeding:

 

Make a backup copy of your project

Make a list of the changes you made to the numerical wells object; you may wish to export out the well attributes to a CSV file (right-click on Wells in the numerical model and select Edit Attributes; save this file as a separate XLS or .CSV file), and use this as a means of checking your new wells later on.

Once you have finished, cross-check the wells in the conceptual and numerical model to verify your data are correct, and if necessary, adjust the rates/schedules.

If your previous wells object contained point source concentrations, then re-assign these values to the new wells object.

 

Deleting Old Wells Objects

 

->In a Numerical Model

Open the project and expand the Model Explorer

Locate the Wells object, under Run/Inputs/Boundary Conditions/Wells

Right click on this object and select "Delete"

Click Yes to proceed when the warning message appears.

Proceed to the next section to also delete the Conceptual Wells from the same project.

 

->In a Conceptual Model

 

Open the project and expand the Model Explorer

Locate the Conceptual Pumping Wells object, under Simulation Domain / Model Domain / Boundary Conditions / Wells

Right click on this object and select "Delete"

Click Yes to proceed when the warning message appears.

NOTE: deleting the conceptual pumping wells object will also remove the corresponding numerical wells from any numerical models that were derived from that conceptual model.

 

Creating a New Wells Object

 

->In a Numerical Model

Select the Numerical Model workflow tab (from the list of active viewers/workflows across the top of the main window)

Go to the Define Boundary Conditions step

Under Toolbox, choose "Wells" from the list of available boundary condition types

Select Assign / Using Data Object; as shown below.
 

 

The following window will appear:

 

 

Enter a name for the wells

On the Data tree, locate the "raw" pumping wells object that you imported into the project

Click once on the caption for this well to select it.

Drag the wells into the empty text box under "Select Raw Wells Object"

Release the mouse button

The list of wells will appear in the window; an example is below

 

 

Review the well data, then click OK to complete the process.

A new item will appear on the Model Explorer under  Run/Inputs/Boundary Conditions/Wells, and the new wells should appear in the Flex viewer (note if you are viewing by layer, you may need to scroll to the appropriate layers to see the new wells in those screened intervals)

Note: Creating a new wells object will also create a corresponding Conceptual Model Pumping Wells object; the data for these two wells are the same.

Once the new wells object is created, you can edit the attributes by selecting Edit/Well from the toolbox, and select any well in the numerical model.

Verify that the new wells object contains the correct values, and if necessary make the appropriate corrections. If your previous wells object contained species concentrations, then re-assign these now.

 

Creating a New Wells Object

 

->In a Conceptual Model

Note: This step is only necessary if you have just a conceptual model with no numerical models.

Select the Conceptual Workflow tab (from the list of active viewers/workflows across the top of the main window)

Go to the Define Boundary Conditions step (as shown below)

 

 

Select Define Pumping Wells. A Create Well Boundary Condition window will appear; the layout is identical to what is shown in the section above for creating wells in the Numerical Model.

Enter a name for the wells

On the Data tree, locate the "raw" pumping wells object that you imported into the project

Click once on the caption for this wells object to select it.

Drag the wells into the empty text box under "Select Raw Wells Object".

Release the mouse button

The list of wells will appear in the window

Verify that the new wells object contains the correct values, and if necessary make the appropriate corrections. If your previous wells object contained species concentrations for a transport run, then re-assign these now.

Click OK to complete the process.

A new item will appear on the Model Explorer under Simulation Domain / Model Domain / Boundary Conditions / Wells

Once the new wells object is created, you can edit the attributes by right-clicking on the Wells object from the Model explorer under Simulation Domain / Model Domain / Boundary Conditions and selecting Edit Boundary Condition from the menu as shown below.
 

 

 

Options for Wells in the Numerical Model

 

When you are working in the numerical model, there are two options for adding wells to your model

 

Assign / Wells

 

Allows you to point and click at locations in the grid (in the current layer) to define one or more well locations.  This option is useful if you want to add just a few wells with a simple schedule, and do not have this data already in an Excel file.

 

Select the desired model layer where you want to add a well

Choose Assign/Wells

Using the left mouse button, point and click at the desired location.

When you are finished, click on the "Finish" button on the Toolbox (this can be found under the "Assign" option), or right-click anywhere in the layer view of the grid and select "Define Attributes".  

In the case where a wells object already exists, the following window will appear: (if there are no wells in the project, then the "Edit Wells" window will appear as explained below.

 

 

The newly created wells can be added to an existing wells object (new conceptual wells only!) or you can add these wells to a new wells group. This scenario is useful if you want to categorize and distinguish wells in your model (for example separate injection or pumping wells, private vs. public supply wells, etc.)

Click OK

The "Edit Wells" window will appear; in this window you can define the screen geometry and pumping schedule.  When you add a well with the click of a mouse, the default screen that is created will be fully over the layer thickness; the well Z max will be top of layer 1 and the well Z min will be the bottom of the bottommost layer.

Click OK to finish creating the wells.

 

Assign / Using Data Object

 

Allows you to create a pumping wells object by using an imported wells object as the data source.

 

Select the Numerical Model workflow tab (from the list of active viewers/workflows across the top of the main window)

Go to the Define Boundary Conditions step

Under Toolbox, choose "Wells" from the list of available boundary condition types

Select Assign / Using Data Object; as shown below.
 

 

The following window will appear:

 

 

Enter a name for the wells

On the Data tree, locate the "raw" pumping wells object that you imported into the project

Click once on the caption for this well to select it.

Drag the wells into the empty text box under "Select Raw Wells Object"

Release the mouse button

The list of wells will appear in the window; an example is below

 

 

Review the well data, then click OK to complete the process.

 

 

Accommodating Wells with Different Start Times

 

If you choose a wells data object that contains wells that start at different times, then you will receive a warning when attempting to use this object to create pumping wells; an example is shown below:

 

 

The following validations are done:

1.The pumping well start date must occur on or after the model start date; any wells with a pumping schedule before the start date will be truncated (cut-off)

2.All wells must start at the same start date, and this must be the model start date; in practice, this may not always occur, so VMOD Flex will automatically insert pumping rate of 0 for all wells that do not start at the model start date.

 

 

Edit Wells

Browse to a layer that contains a well; it will appear as a point (colored pink)

Select Edit/Single

Click on a Well in the layer view

The Edit Wells window will appear as explained above.

Make the desired edits then click OK to apply the changes.

 

Wells can be set as active/inactive for the simulation; use the "Active" column in the Wells grid to set the appropriate option; wells that are set as Inactive will not be translated to the .WEL package.

 

Transport Parameters (Species Concentrations)

When you have Transport set as active in the Modeling Objectives, you will have the option to define species concentrations to injection wells; this can be done in the Pumping Schedule, under the "Conc001" column. The injected concentration is assigned to the entire well interval.  The default value of -1 is a flag indicating that the injected water does not contain the associated species.  One column will be added to the pumping schedule for each species defined in the Modeling Objectives step - the column header will corresponds to the species name.

 

Export

The pumping wells can be exported to a comma separated value (CSV) file; right click on the Model Explorer and select "Export"; a CSV file will be generated which can be loaded into a text editor or Excel.

 

 


Page url: http://www.waterloohydrogeologic.com/help/vmod-flex/index.html?vm_wells.htm