Anisotropic Refinement for Reservoir Fracture Meshing
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Solution Overview
Problem
Current reservoir modeling techniques, such as structured and unstructured meshing, face challenges in accurately simulating fractures in hydrocarbon reservoirs, particularly when dealing with complex geometries, leading to inefficiencies and increased computational burdens.
Innovation Solution
The implementation of anisotropic geometry-adaptive refinement (AGAR) methods that modify a structured grid to create a computational mesh with higher resolution in near-fracture areas, allowing for accurate representation of fracture networks and reducing computational requirements by applying anisotropic refinement algorithms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If structured meshing techniques are used, then mesh generation is robust and systematic, but mesh resolution in near-fracture areas is insufficient for accurate fracture modeling
Solution Approach 1:
The patent applies local quality by implementing anisotropic refinement that selectively increases mesh resolution in near-fracture areas while maintaining coarser resolution in distant regions. This is achieved through geometry-adaptive algorithms that identify fracture surfaces and apply targeted refinement criteria only to cells adjacent to fractures, thereby improving local mesh quality without uniformly increasing global complexity
Solution Approach 2:
The patent segments the computational domain into regions based on proximity to fracture surfaces. Cells are classified into near-fracture regions requiring high resolution and far-field regions acceptable with coarser resolution. This segmentation enables differential refinement strategies that improve critical areas while maintaining overall computational efficiency
2Adaptability or versatility
If fully-unstructured meshing techniques are used, then complex fracture geometries can be represented, but computational cost and complexity increase significantly
Solution Approach 1:
The patent maintains structured mesh properties in far-field regions while applying unstructured refinement locally near fracture surfaces. This hybrid approach preserves the computational efficiency of structured meshes in bulk regions while capturing complex fracture geometries through localized unstructured refinement, thereby reducing overall computational complexity compared to fully-unstructured approaches
Solution Approach 2:
The patent transitions from isotropic refinement (uniform in all directions) to anisotropic refinement (directional and selective). By refining mesh cells preferentially in directions perpendicular to fracture surfaces while maintaining coarser resolution parallel to fractures, the method achieves accurate geometric representation with fewer total elements, reducing computational complexity
3Manufacturing precision
If local grid refinement is applied, then mesh resolution near fractures is improved, but computational time increases for general reservoir geometries
Solution Approach 1:
The patent implements geometry-adaptive refinement that automatically identifies fracture surfaces and applies refinement only to cells in near-fracture regions. This selective approach concentrates computational resources where they are most needed for accurate fracture modeling, avoiding the excessive computational time required by uniform refinement of entire reservoir models
Solution Approach 2:
The patent employs anisotropic refinement that changes mesh parameters directionally, refining cells primarily in the direction perpendicular to fracture surfaces while maintaining larger cell dimensions parallel to fractures. This parameter change strategy achieves accurate fracture representation with significantly fewer refined cells compared to isotropic refinement, reducing computational time
Data Source
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AI summary
A system and method inserts fracture networks into an existing Earth Model that exists as a structured grid and physical property values. The fracture network is in the form of a surface mesh (manifold or non-manifold) in a three-dimensional ("3D") space. The structured grid of the Earth Model is then anisotropically refined to resolve the fractures and to provide appropriate cell grading in the near-fracture region. The generated Earth Model may be utilized in a variety of applications, including for example, a reservoir simulation.