Static Earth Model Grid Cell Scaling for Reservoir Simulation Accuracy
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Solution Overview
Problem
Determining an appropriate grid cell size for geologic grids in reservoir simulations is challenging, as smaller cells increase complexity and time-consuming computations, while larger cells may not accurately represent downhole conditions, affecting the accuracy of hydrocarbon production monitoring and planning.
Innovation Solution
A grid cell scaling process is employed, where predetermined rules determine the scaling of grid cells in a static earth model, assessing accuracy through connectivity, tortuosity, and Euler number comparisons, with adjustments made to ensure attributes are within a threshold tolerance, allowing for accurate fluid flow simulations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If grid cell size is decreased to improve accuracy of downhole conditions representation, then measurement precision is improved, but device complexity and computation time increase
Solution Approach 1:
The reservoir is divided into multiple grid cells with different sizes, where each grid cell can have a size appropriate to the local geological features. This segmentation allows fine resolution in areas requiring high accuracy while using coarser resolution in other areas, thereby maintaining measurement precision without uniformly increasing device complexity across the entire model.
Solution Approach 2:
Different regions of the reservoir model are assigned different grid cell sizes based on local requirements. Areas with complex geological structures or high production importance use smaller grid cells for higher accuracy, while less critical areas use larger grid cells to reduce computational burden. This local quality approach optimizes the balance between accuracy and complexity.
2Device complexity
If grid cell size is increased to simplify computations, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The computational domain is segmented into regions with different grid resolutions. By strategically placing finer grid cells only where needed rather than uniformly across the entire reservoir, the overall computational complexity is reduced while maintaining necessary measurement precision in critical areas.
Solution Approach 2:
The model applies different grid cell sizes locally based on geological and production requirements. This ensures that computational simplicity is achieved in areas where high precision is not critical, while maintaining adequate accuracy in regions where it is essential for reliable hydrocarbon production monitoring.
3Reliability
If grid cell size is decreased to improve simulation accuracy, then reliability is improved, but loss of time increases
Solution Approach 1:
The reservoir model uses segmented grid cells where fine resolution is applied only to specific zones requiring high simulation accuracy, such as areas near production wells or complex geological structures. This segmentation reduces the total number of grid cells compared to a uniformly fine grid, thereby reducing computation time while maintaining reliability in critical regions.
Solution Approach 2:
Different grid cell sizes are assigned to different regions based on their importance to reservoir simulation accuracy. This local quality approach ensures that computational resources are focused on areas where high accuracy is most valuable for reliable production forecasting, while reducing computational burden in less critical areas.
Data Source
AI summary
At least some of the disclosed systems and methods obtain a static earth model having a three-dimensional grid with multiple cells, each cell having petrophysical properties associated therewith. Further, at least some of the disclosed systems and methods adjust a size of at least some of the cells based on a predetermined scaling rule. Further, at least some of the disclosed systems and methods re-sample petrophysical properties for the adjusted grid cells. If the one or more attributes of the static earth model are within a threshold tolerance after the adjusting and re-sampling steps, the static earth model is used as input to a flow simulator.