Aquifer Cell Aggregation for Reservoir Simulation Speedup
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current reservoir simulation models require significant computational resources to handle large aquifer regions, often resulting in reduced grid resolution and inaccurate simulation results due to aggressive coarsening methods or the use of simplistic analytical models that fail to represent the complex geometry and heterogeneity of aquifers.
Innovation Solution
The method involves vertical aggregation of aquifer cells and equilibrium calculations to recover pressure solutions in original fine cells, reducing computation time while maintaining high accuracy by retaining full geologic descriptions and complex structures, applicable to both structured and unstructured grids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If aggressive grid coarsening is applied to aquifer regions to reduce computational expense, then simulation speed is improved, but grid resolution and accuracy are degraded
Solution Approach 1:
The patent segments the reservoir model into two distinct parts: hydrocarbon-bearing regions and aquifer regions. This segmentation allows different treatment methods to be applied to each region, enabling fine grid resolution in hydrocarbon regions while using coarsened grids in aquifer regions, thus resolving the contradiction between simulation speed and accuracy.
Solution Approach 2:
The patent applies local quality by treating aquifer grid cells differently from hydrocarbon-bearing grid cells. Specifically, aquifer regions undergo coarsening to reduce computational expense, while hydrocarbon regions maintain fine grid resolution to preserve accuracy. This localized differentiation resolves the contradiction by optimizing each region according to its specific requirements.
2Productivity
If analytical aquifer models are used to replace detailed aquifer cell modeling, then computational resources are reduced, but modeling accuracy for complex geometry and heterogeneity is degraded
Solution Approach 1:
The patent extracts the essential features of aquifer modeling by coarsening the grid while retaining key aquifer properties and characteristics. Instead of using simplified analytical models that lose geometric and heterogeneity information, the method extracts and preserves critical aquifer attributes in a coarsened grid structure, thus maintaining reliability while improving computational efficiency.
Solution Approach 2:
The patent implements dynamic adaptivity by allowing the simulation to switch between fine and coarsened grid representations based on the specific region and simulation requirements. The coarsening process is designed to be adaptive, adjusting the level of detail based on local aquifer properties and the need to balance computational efficiency with modeling accuracy.
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
Reservoir simulation for simulation models which include a large edge aquifer region is provided with a speed up in processing reducing computer processing time. Connected aquifer grid cells in a vertical column are amalgamated to reduce the total number of active cells in the solution phase. The fine grid property data is maintained for computing distributed 3D graph, and connection factors (transmissibilities), as well as pore volume and compressibility calculation of coarsened aquifer cells during nonlinear solution phase. Since the work load in the solution phase is proportional to the total number of active cells, a significant speedup in simulation time is provided. The aquifer fine grid pressures are computed using vertical equilibrium treatment of hydraulic potential inside an amalgamated aquifer coarse cell.