A method for pore-scale simulation of single-phase shale oil flow based on three-dimensional digital cores with hybrid mineral phases

Abstract

The mineral properties of the pore walls have a great influence on the single-phase shale oil flow at the pore scale. In this paper, a new method is proposed for pore-scale simulation of single-phase shale oil flow based on digital cores with hybrid mineral phases. This method can identify each mineral pore wall and correspondingly consider the adsorption layer and slippage boundary condition. First, three-dimensional (3D) digital cores with hybrid mineral phases are reconstructed from two-dimensional (2D) scanning electron microscope images of a shale sample, and correspondingly the pore space is divided with computational grids. Second, a mathematical model of shale fluid flow is established based on the Navier–Stokes (N–S) equation, combined with the slip length and viscosity formula. Finally, the equations are discretized on the mesh by the finite volume method and solved by the semi-implicit method for pressure-linked equations for flow simulation of shale oil in the 3D digital cores. By applying the method, we analyze effects of total organic carbon in volume, slippage, and adsorption on the single-phase shale oil flow based on 3D digital cores with hybrid mineral phases.