Pre Meshing

Perform Pre Meshing operations on the imported model.

You will perform the pre meshing tasks for the imported model before proceeding to meshing and deck setup operations.

  1. Hole/Gap Fill of discontinuous horizons.
  2. Refine mesh to achieve better mesh quality.
  3. Verify Horizon intersections.
  4. Split Faults

Hole & Gap Fill

Fill a gap in the Horizon-C and Horizon-F components.

Using the Hole/Gap Fill option, you will fill a gap present in the Horizon-C and Horizon-F components.
  1. From the model browser, isolate Horizon-C in the graphics area.
  2. Click Mesh icon, select Mesh > Hole/Gap Fill.
    Figure 1.
    Hole/Gap Fill dialog will appear.
  3. Select Gap Fill from Fill Type list.
  4. Select Node List for Select Entities type.
  5. Using the node list selection panel, select node paths on the opposite edges of the gap.
  6. Check Remesh box.
  7. Click Fill.
    This fills the gap with the original mesh size value.
  8. Repeat the above steps to fill the gap in Horizon-F component.

Rebuild Mesh

Use Rebuild option to rebuild the mesh of components.

Rebuild operation allows you to correct and achieve your desired element size in the existing mesh. This will lead to better model for tetra mesh operation. Using the Rebuild, you will remesh all the components in the model.
Note: In order to perform Rebuild, you will have to import the mesh parameter and mesh criteria files to the session. The sample parameter and criteria files, geod_500.param and geod_500.criteria are present in the Tutorial folder.
  1. From gMesh group, select Rebuild.
    Figure 2.
    A guide bar will appear.
  2. Click to open additional options.
    Figure 3.
  3. Click Edit parameters. A dialog will appear.
    Figure 4.
  4. Click .
    A file browser will appear. Browse and select the geod_500.param file.
    This will update the mesh parameter for the session from selected file.
  5. Similarly, load the geod_500.criteria file for Edit Criteria settings.

Mesh Rebuild Definition:

For the tutorial purpose, you will rebuild mesh for the following components-
  • Fault A
  • Fault B
  • Fault C
  • Horizon Top
  • Horizon A
  • Horizon B
  • Horizon C and
  • Horizon F

  1. Select the advanced options button () next to Elements button.
  2. Select Horizon Top from the list.
  3. Click Rebuild.
    Important: Rebuild one component at a time. This results in better mesh control and machine performance.
    Repeat the mesh rebuild process for the above listed components. This ensures the average element size for the model is 500.

Horizon Intersection

Use Horizon tool to check and fix horizon intersections.

Using the Horizons tool from the Fix group, you can check and fix the horizon intersection. For the tutorial purpose, you will use auto and manual methods to fix the intersections in the model.

Auto Method

  1. From the model browser, isolate Horizon-D and Horizon-E components
  2. From Fix group, select the Horizon tool.
    Figure 5.
    A guide bar will appear.
  3. Click to open additional options.
  4. Enter 600 in the Push: Mesh Tolerance value field.
  5. Click Select Displayed.
    The Horizon-D and Horizon-E are selected.
  6. Click Intersect All.
    This intersects the selected horizons and duplicate elements are deleted.

Manual Method

Isolate Horizon-C and Horizon-D components.

  1. From Fix group, select the Horizon tool. Deactivate to enable the manual method.
  2. Click Select Displayed.
    Horizon-C and Horizon-D are selected.
  3. Click Find.
    This identifies the horizon intersections and displays a micro dialog for next operation.
  4. Click Push: Pinchout .
    This pushes the intersecting elements away from each other, with the older horizon being forced below the younger one. The minimum unit thickness now corresponds to the value specified.
  5. Click Next to find the next intersection.
  6. Click Intersect and Remesh for the larger intersection patch. Click Delete in the microdialog.
    This cuts and stitches the intersecting horizons and deletes the duplicate elements.

Intersect Faults

Intersect and split faults using the horizons.

Using the Faults tool, you will find and tie fault-horizon intersections in the model.
  1. From Fix group, select the Faults tool.
    Figure 6.
    A guide bar will appear.
  2. Click Displayed Faults.
    This will select all the displayed faults.
  3. Click Displayed Horizons.
    This will select all the displayed horizons.
  4. Click .
    This will intersect all the faults and horizons. This also splits the faults and organizes them into sub components delineated by the stratigraphy.
    Figure 7.

Enclose

Use Enclose option to create walls for all the horizon component pairs.

In order to generate a tetra mesh, a model should contain enclosed volumes. To create these, you can use Enclose options to create walls along the boundaries of the horizon components.
  1. From the Define group, select Enclose.
    Figure 8.
    A guide bar will appear.
  2. Deactivate to enable manual mode. Select By Horizons from the list.
  3. Click to open additional options.
    Enter 500 for Element Size.
  4. Select Horizon Top and Horizon-A components from the graphics area.
  5. Click Create Walls.
    This creates a wall along the boundary of the selected horizons and new sidewall component will be listed in model browser.
  6. Similarly, create sidewalls between each pair of horizons by choosing them in a top-down (numerically lowest to highest; that is, youngest to oldest) order.
    Once complete, the model with sidewalls should be as below.
    Figure 9.

Auto Organize Components and Elements

Organize model components and fault elements into unique collectors.

Using the Organize option, you will organize the model components into unique enclosed volume assemblies.

Organize Volumes

  1. From Define group, select Organize tool.
    Figure 10.
    A guide bar will appear.

Organize Volumes

  1. Select Enclosed volumes from the list.
  2. Click Select Displayed.
    All parts in the model are selected.
  3. Click .
    The Assemble Enclosed Volumes dialog is displayed. Click OK to accept the organization and close the dialog.
    Figure 11.
    This creates volume assemblies based on the horizon pair and the respective sidewalls. These volumes will now be used for volume tetra meshing.
    Figure 12.