Grid Project:   SFWST VoroCrust for Geologic Applications

Project Purpose

Geometry conforming Voronoi tessellations for geologic flow and transport calculations are the goal of this project. These will be used in flow and transport codes FEHM and PFLOTRAN but will also be applicable to modeling with Amanzi and Tough2.
This work is supported by Spent Fuel and Waste Disposition (SFWD) programs within the Spent Fuel and Waste Science and Technology (SFWST) Campaign of the U.S. Department of Energy (DOE) Office of Nuclear Energy (NE). The program is tasked with conducting research and development (R&D) related to geological disposal systems.
This year SNL will work with VoroCrust to develop Voronoi geometric coefficients for PFLOTRAN for use in idealized sample models. LANL is continuing work with VoroCrust to develop a meshing workflow for FEHM, PFLOTRAN and geologic models in general.

VoroCrust Abstract arxiv.org/abs/1902.08767
VoroCrust: Voronoi Meshing Without Clipping PDF
VoroCrust Supplemental Materials PDF

Meshing Workflow for VoroCrust

• Given a 3D GFM, write the VoroCrust input surface.
• Use VoroCrust to create a volume filled Voronoi Mesh.
• Write basic mesh and model setup files for the Modeling Software.
• Provide Visualization files for mesh evaluations and simulation results.
• Develop capabilities for boundary conditions, zone selections, variable resolution, complex non-manifold geometries.

LANL Meshing Examples for VoroCrust

The following are example geologic geometries used with VoroCrust to explore meshing parameters and results. These include both manifold and non-manifold geometries with internal boundaries. The files are available on github LANL (Private).

2 Unit Cubes - Simple Example for Testing

This is multi-material with one internal boundary, 2 unit cubes.
This allows for easy testing of volumes, parameter options, and VIS methods.
This example includes a buffer to protect corners (not needed), and a no buffer versions. VoroCrust generates seeds away from the boundary and far enough to capture the corners.

Developed method to VIS Voronoi cells from vorocrust seeds using LaGriT interpolation method.
Includes Delaunay Tet mesh files for FEHM modeling

Gallery of Unit Cubes Work Gallery

Input Surface

VoroCrust Exterior and Interior seeds

VoroCrust Surface Mesh

Voronoi Cells Interpolated from seeds

Mortandad Mesa - Test small DEM from real data

Surface with Mortandad Mesa DEM and no internal boundaries, thick and thin versions of depth from top.
Includes of VIS Voronoi cells from vorocrust seeds using LaGriT interpolation method.
Thin layer version tested with flat bottom 10m from lowest top elevation

Gallery of Mesa Shell Mesa Gallery

Gallery of Mesa Thin Layer Thin Mesa Gallery

Mortandad Seismic Project Page Grid Project Page

Input Surface	VoroCrust Surface Mesh	VoroCrust Surface Mesh of Thin Layer	Detail of VoroCrust Thin Layer
Voronoi Cells shown on corner subset	Voronoi Cells on Corner Surface	Voronoi Cells Corner Interior Volume	Voronoi Cells Inner Volume Thin Mesh

GDSA GFM Cubes - Test 4 Simplified GFM Models

These are the 4 Cube Tests from JewelSuite used as test GFM's for the SFWD-GDSA Workflow Integration Project.
These represent test GFM models with 1. horizontal layers, 2. pinchout, 3. lens, and 4. fault.
See the gallery for images of the VoroCrust input surfaces and the VoroCrust Meshing results.

Gallery of VoroCrust Meshing Gallery

Images are clipped from the front to show the internal boundaries.

VoroCrust Mesh Test 1

VoroCrust Mesh Test 2

VoroCrust Mesh Test 3

VoroCrust Mesh Test 4

Wyoming Uplift - Test Slopes of 25 degree and greater

These surfaces are from the EarthVision GFM representing the Wyoming Uplift. This model can be difficult for meshing, some of the layers are thin with respect to the region they cover and the slopes of each surface vary subtley with the next layer. Additionally, the slopes of these surfaces range from 6 degrees to over 25 degrees. The challenge is to capture these slopes as well as the thin layers.
The faults were not used in these examples.

Gallery of VoroCrust Meshing Gallery

Images are clipped from the front to show the internal boundaries.

Note: There are VoroCrust solutions for all the shell (manifold) examples but not the 7 layer (non-manifold) examples.

Wyoming Uplift GFM	Input Surfaces for Slopes 3x	VoroCrust Mesh for Shell 3x MANIFOLD
Input Surface from FEHM CO2 Incline MANIFOLD	VoroCrust Mesh for CO2 Incline

Fracture Networks - Test dfnWorks planes in cubes

These 2D fractures were generated using dfnWorks. The fractures were put into a bounding cube for meshing with VoroCrust.
There are 2 fractures tests, a single fracture and a set of 4 fractures.
There are 2 versions of the bounding box, one is connected to fractures, the other is not.

Gallery of VoroCrust Meshing Gallery

Images are clipped from the front to show the internal boundaries.

Note: There are currenty no VoroCrust solutions for any of the hanging or floating fractures.

Input Surface for 1 Hanging Fracture

Input Surface for 4 Fractures