Pore-Scale Simulation for Fluid Flow in Digital Rocks Based on Decoupled Stokes Equation

Microscopic flow simulation of digital rock cores plays a crucial role in understanding and predicting fluid behavior in porous media, applicable across a range of energy technologies including carbon sequestration, hydrogen storage, geothermal energy, and fuel cells. Permeability is a key parameter for quantifying fluid flow in porous media. Utilizing the Stokes equation in 3D digital rocks to perform pore-scale simulations can estimate the core’s equivalent permeability, but simulations of digital cores with complex pore structures and a large number of voxels require extremely high computational costs. This study introduces a novel method for microscopic flow simulation in digital rocks, which simplifies the 3D pore-scale simulation into multiple decoupled 2D ones. By this decoupled simulation approach, the expensive simulation based on the Stokes equation is conducted only on 2D domains, and the final 3D simulation of the Darcy equation using the finite difference method (FDM) is very cheap. The proposed method is particularly suitable for isotropic or relatively homogeneous rock samples, enabling accurate estimation of equivalent permeability and reconstruction of fine-scale pressure and velocity fields. It also offers significant advantages in computational efficiency, making large-scale and complex flow simulations feasible.