Oil–Water Relative Permeability in Shale Considering the Effect of Kerogen: Modeling and Analysis

Abstract

\n Nontrivial initial water and the indispensable hydraulic fracturing technique for enhanced recovery result in the prevalence of oil–water two-phase flow in shale oil reservoirs. However, limited research has focused on their presumably unique flow characteristics so far. In this paper, based on assumptions about the two-phase distribution pattern, the relative permeability models for organic/inorganic pores are established. Then, the two models are combined by an upscaling model to arrive at the expression for the relative permeability of shale rocks. Effects of total organic carbon (TOC), pore size, and slip length are considered. Sensitivity analysis demonstrates their impacts on the relative permeability of inorganic/organic media and the shale rock. This is the very first work that provides an analytical relative permeability model for the oil/water two-phase flow in shale matrix considering the effect of kerogen, and it is important for understanding the performance of shale oil reservoirs and other kinds of nanoporous media.