Automatic Local Grid Refinement in Reservoir Simulation
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Solution Overview
Problem
Current reservoir simulation methods lack a systematic process to determine the extent of fine grid zones and their boundaries in low permeability reservoirs, leading to computational inefficiencies and inaccurate flow modeling.
Innovation Solution
A computer-implemented method that applies a coarse grid to a geologic formation, identifies structures of interest, and determines a fine grid zone based on simulation time and geologic characteristics using the equation X val = 10 * a * time * k * por, where X val is the distance from the structure, time is the simulation period, k is the average permeability, por is the average porosity, and a is an empirical constant, to optimize grid refinement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fine grid is applied throughout the entire reservoir, then flow modeling accuracy near structures is improved, but computational cost and processing time increase significantly
Solution Approach 1:
The patent applies local grid refinement by creating fine grid zones only in specific regions surrounding structures of interest (wells, fractures, faults) while maintaining coarse grids in the remainder of the reservoir. This localized approach concentrates computational resources where they are most needed for accurate flow modeling, rather than uniformly refining the entire grid.
Solution Approach 2:
The reservoir grid is segmented into multiple zones with different resolutions: fine grid zones around structures and coarse grid zones in the bulk reservoir. This segmentation allows the model to achieve high accuracy near structures while maintaining computational efficiency in regions where fine resolution is not critical.
2Measurement precision
If a fine grid zone is extended further from the structure, then flow modeling accuracy is improved, but computational complexity and processing time increase
Solution Approach 1:
The patent implements a systematic approach to determine the optimal extent of fine grid zones using a calculation that balances accuracy requirements with computational feasibility. Rather than extending fine grids to excessive distances or arbitrary boundaries, the method calculates a specific radius based on reservoir properties and simulation parameters, applying fine grid resolution only to the extent necessary for accurate flow modeling.
3Measurement precision
If manual determination of fine grid zone boundaries is performed, then modeling accuracy can be optimized, but the process becomes more complex and time-consuming
Solution Approach 1:
The patent implements an automated system that calculates fine grid zone boundaries based on reservoir properties (permeability, porosity), simulation parameters (time step, total simulation time), and structural characteristics. The system self-determines the optimal fine grid extent using a systematic calculation method, eliminating the need for manual intervention while maintaining scientific rigor and consistency.
Solution Approach 2:
The method systematically varies and optimizes key parameters including the fine grid zone radius (Xval), grid block dimensions, and refinement criteria based on reservoir heterogeneity and flow dynamics. These parameter changes are driven by quantitative relationships between permeability, porosity, time, and spatial extent, allowing automated optimization of grid configuration.
Data Source
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AI summary
A system and method of automatic local grid refinements in reservoir simulation systems is described. In one aspect of the disclosure, a method is directed to a computer-implemented method of modeling a formation. The method includes applying a coarse grid to a geologic formation of interest, the coarse grid having a plurality of coarse grid blocks and identifying a structure of interest disposed in the formation. Further, the method includes determining a fine grid zone around the structure based upon a time period for flow simulation of the geologic formation and a geologic characteristic of the geologic formation in a local region adjacent the structure and applying a fine grid to the coarse grid blocks encompassed by the fine grid zone.