Subterranean Grid Mesh Optimization for Fault Representation

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Solution Overview

Problem

Current methods for constructing 3D meshes in complex geological environments with faults are inadequate, leading to degenerate quadrilaterals and suboptimal mesh quality, which hinders precise basin simulation and CO2 injection simulations.

Innovation Solution

A method that optimizes mesh quality by deforming a two-dimensional grid to minimize node displacement, using a reference grid with regular meshes and imposing node displacements based on fault locations, while ensuring non-degeneracy and optimal shape of mesh elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the constrained grid method is used to construct 3D mesh with faults, then the mesh can represent complex geological geometry, but the mesh quality near faults becomes suboptimal with degenerate quadrilaterals

Engineering Contradiction:
Improveability to represent complex geological geometry with faultsVSAvoidmesh quality and element shape
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The invention applies preliminary smoothing actions to the grid before constructing the 3D mesh. The smoothing process pre-adjusts node positions to prevent the formation of degenerate quadrilaterals, ensuring that when faults are later introduced, the mesh maintains high quality throughout the domain.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The smoothing process applies local quality improvement by specifically targeting areas near faults where degenerate elements are most likely to form. The algorithm iteratively adjusts node positions in regions of poor mesh quality while preserving the overall geological structure representation.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If regular two-dimensional grids are deformed to account for faults, then fault positions are represented, but the dispersion of neighboring quadrilaterals is not optimized

Engineering Contradiction:
Improvefault position representationVSAvoidquadrilateral dispersion and uniformity
Core Design Contradiction:
Measurement precisionVSShape

Solution Approach 1:

The smoothing process uses feedback from the initial fault-aligned grid configuration to iteratively improve quadrilateral dispersion. The algorithm calculates mesh quality metrics and uses this feedback to guide node adjustments, continuously optimizing the uniformity of neighboring quadrilaterals while maintaining fault position accuracy.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The grid transformation is made dynamic through iterative smoothing operations. Instead of a single static deformation, the grid undergoes multiple refinement passes that progressively optimize quadrilateral shapes and dispersion, adapting the mesh quality throughout the deformation process.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2667360B1Method of exploitation of a subterranean environment according to an exploitation scheme defined by an optimised representation
Publication Date: 2019.07.17 IFP ENERGIES NOUVELLES
  • EP2667360B1 patent drawingFigure 1~2b
  • EP2667360B1 patent drawingFigure 3a~4
  • EP2667360B1 patent drawingFigure 5~6

AI summary

The method involves optimizing quality of meshes of gridline by displacing nodes of gridline by using a gridline deformation minimizing method. A reference gridline is generated, where the gridline comprises regular meshes and covers entirely the gridline to be optimized. Displacement of a node i.e. rigid node, of the reference gridline is imposed on a corresponding node in the gridline to be optimized. An optimized two-dimensional (2D) gridline is constructed by displacement of other nodes of the reference gridline while minimizing the field of displacement of the nodes. An independent claim is also included for a computer program product comprising program code instructions for implementing a method for exploitation of an underground medium.