CAD Porous Media Flow Simulation for Residual Fluid Capture
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Solution Overview
Problem
Existing methods for simulating multiphase fluid flows in porous media require full resolution of all scales, leading to computationally prohibitive data size and resource demands, and fail to accurately capture residual fluid amounts in under-resolved pore structures.
Innovation Solution
A method for digitally simulating multi-scale fluid flow using a digital representation of a porous medium based on a CAD model, which applies counteracting body forces and resistance forces to voxels to reduce surface tension and simulate residual fluid amounts in under-resolved pore structures, utilizing constitutive relationships and Hessian matrix-based directionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If full scale resolution is used to simulate fluid flow in porous media, then simulation accuracy is improved, but computational complexity and resource requirements increase prohibitively
Solution Approach 1:
The simulation domain is segmented into multiple scale levels (e.g., pore scale, voxel scale, reservoir scale). Each scale is simulated separately with appropriate resolution, avoiding the need to resolve all scales simultaneously. The pore-scale physics are captured in representative elementary volumes (REV), which are then upscaled to voxel-scale simulations, and finally to reservoir-scale models.
Solution Approach 2:
Multiple simulation models are nested within each other across scales. Pore-scale simulations are embedded within voxel-scale models, which are in turn embedded within reservoir-scale models. Information from finer scales (pore structure, capillary pressure curves, relative permeability) is used to parameterize coarser scale models, creating a hierarchical nested structure that captures multi-scale physics without requiring full resolution at all scales.
2Measurement precision
If full scale resolution is used to simulate fluid flow in porous media, then simulation accuracy is improved, but computational resource requirements increase prohibitively
Solution Approach 1:
The computational domain is segmented into different scale levels with varying resolution requirements. Pore-scale regions are simulated with high resolution only where necessary (e.g., around fluid interfaces), while bulk regions use coarser voxel-scale or reservoir-scale models. This segmentation reduces the total number of grid cells and computational operations required.
Solution Approach 2:
Instead of fully resolving all scales throughout the entire domain, the method applies partial resolution only where critical physics occur (e.g., capillary trapping zones, fluid interfaces). In regions where full resolution is not critical, coarser models are used, reducing computational resource requirements while maintaining accuracy where it matters most.
3Device complexity
If voxel size is increased to reduce computational complexity, then computational resources are reduced, but the ability to capture residual fluid in small pores is lost
Solution Approach 1:
Pore-scale simulations are performed in advance to characterize capillary pressure-saturation relationships and relative permeability for different pore size distributions. These pre-computed constitutive relationships are then used to parameterize voxel-scale and reservoir-scale models, allowing coarse voxel models to capture residual fluid effects without explicitly resolving individual small pores.
Solution Approach 2:
The voxel model incorporates effective parameters (capillary pressure curves, relative permeability, porosity) that are derived from pore-scale physics and adjusted to represent the averaged behavior of multiple pore sizes within each voxel. This parameter transformation allows coarse models to capture fine-scale physics through upscaled constitutive relationships rather than explicit geometric resolution.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Reduces computational complexity and resource requirements while improving simulation accuracy by capturing residual fluid components and correcting surface tension effects, aligning with high-resolution simulations without the cost and time of full scale resolution.
Implementation Method 1
applies counteracting body forces and resistance forces to voxels to reduce surface tension
Implementation Method 2
determining a first capillary pressure and a second capillary pressure for the porous medium
Data Source
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AI summary
Systems and methods for digitally simulating a multi-scale fluid flow in a three-dimensional computer-aided design (CAD) model of a simulation space include digitally simulating movement of a fluid interface through a digital representation of a porous medium including a mesh including voxels, the fluid interface representing a separation between a first fluid and a second fluid; and digitally simulating residual amounts of the first fluid and the second fluid in pore structures in the porous medium by determining a first capillary pressure and a second capillary pressure for the porous medium; determining values for voxels in the mesh representing locations in the porous medium associated with the pore structures, the values being based on the first and second capillary pressures and porosity values for the locations in the porous medium; and determining the residual amounts of the first fluid and the second fluid at the voxels based on the values.