A novel meshless numerical simulation of oil-water two-phase flow with gravity and capillary forces in three-dimensional porous media

This paper presents a novel fully implicit scheme for simulating three-dimensional (3D) oil-water two-phase flow with gravity and capillary forces using the meshless generalized finite difference method (GFDM). The approach combines an implicit Eulerian scheme in time with a GFDM discretization method in space to compute implicit solutions for the pressure and saturation in the flow control equations. The research introduces an L2 norm error formula and conducts a sensitivity analysis on the impact of varying influence domain radii on computational accuracy within the Cartesian node collocation scheme. Findings suggest that larger influence domain radii correspond to reduced computational accuracy, providing a preliminary guideline for selecting the domain radius in 3D GFDM applications. Overall, this paper presents an effective and precise meshless method for addressing two-phase flow challenges in 3D porous media, highlighting the promising prospects of GFDM in numerical simulations.