Non-fixed pillar grid adjustment for complex fracture simulation
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Solution Overview
Problem
Discretely gridding complex fractures in geological formations for numerical simulations is challenging, especially when fractures are not orthogonal to the grid orientation, leading to suboptimal results in reservoir and geomechanical simulations.
Innovation Solution
A method that adjusts the position of non-fixed pillars in an initial grid using a multi-point stencil and inverse-distance weighted mean positioning to create refined grids that better align with fractures, ensuring finer meshing near fractures and maintaining an orthogonal grid structure elsewhere.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional grid generation techniques are used, then the grid structure is simple and easy to generate, but the grid cannot accurately represent complex fractures that are not orthogonal to the grid orientation
Solution Approach 1:
The patent applies local quality by creating different grid characteristics in different regions: an initial regular grid is generated for the overall domain, then non-fixed pillars are selectively adjusted in specific regions near fractures to achieve finer meshing and better alignment. This allows the grid to have high precision where needed (near fractures) while maintaining simplicity elsewhere (in the bulk domain).
Solution Approach 2:
The patent segments the grid adjustment process into multiple stages: (1) generating an initial grid, (2) identifying fixed and non-fixed pillars, (3) adjusting only the non-fixed pillars using inverse-distance weighted mean positioning, and (4) regenerating connections. This segmentation allows complex fracture alignment to be achieved through localized adjustments rather than complete grid redesign.
2Measurement precision
If the grid is refined to provide finer meshing near fractures, then the simulation accuracy improves, but the cell-to-cell volume ratio becomes improper and grid quality deteriorates
Solution Approach 1:
The patent uses parameter changes by applying inverse-distance weighted mean positioning to adjust pillar positions. The weighting parameter (inverse distance) controls how much each neighboring pillar influences the new position, allowing continuous adjustment of cell sizes to maintain proper volume ratios while achieving finer meshing near fractures.
Solution Approach 2:
The patent introduces dynamic adjustment of pillar positions during the grid generation process. Non-fixed pillars are iteratively adjusted based on their distance to fixed pillars representing fractures, allowing the grid to adapt its cell sizes dynamically to maintain quality while achieving the desired refinement near fractures.
3Device complexity
If approximations are used to avoid discrete gridding, then the model complexity is reduced, but the ability to explicitly model near-fracture flow and stress is lost
Solution Approach 1:
The patent applies preliminary action by pre-adjusting the pillar positions before final grid generation. By iteratively adjusting non-fixed pillars to achieve optimal alignment with fractures in advance, the grid is prepared to accurately represent near-fracture conditions, enabling reliable explicit modeling of flow and stress without requiring complex alternative models.
Data Source
AI summary
Embodiments of methods and systems for improved gridding of complex networks such as geological fractures are disclosed. In at least one embodiment, a method in accordance with the present disclosure includes adjusting a location of at least one non-fixed pillar of an initial grid, including: establishing a multi-point stencil of pillars that includes the at least one non-fixed pillar; selecting a fixed pillar of the initial grid toward which the non-fixed pillar is to be adjusted; determining a distance from each pillar of the multi-point stencil to the selected fixed pillar; calculating an inverse-distance weighted mean position based on the determined distances of the pillars of the multi-point stencil; and adjusting a position of the at least one non-fixed pillar to the inverse-distance weighted mean position.