Numerical Simulation of Shale Oil Well Productivity Based on Shale Oil-Water Two-Phase Flow Characteristics

The pore structure of shale is complex, and solid-liquid interaction occurs. In addition, its microscopic flow characteristics increase the difficulty of shale oil productivity prediction. In order to accurately evaluate the productivity of shale oil reservoirs with multi-scale pore structures after volume fracturing, the microscopic multi-phase flow characteristics under the action of real pore structure of shale were considered based on the oil-water two-phase relative permeability calculation method and embedded discrete fracture model (EDFM) of shale reservoirs. As a result, a numerical simulation method for shale oil reservoir productivity considering shale volume fracturing was developed. The oil-water two-phase relative permeability curve was calculated based on the pore size distribution of shale reservoirs, and combined with the fracturing/production process of shale reservoirs, the spatial distribution of fracturing fluid in shale oil reservoirs and the productivity evaluation of oil well were simulated and analyzed. The results show that there are differences in the oil-water two-phase relative permeability curves of shale under different pore size distributions. Fracturing fluids are mainly distributed in fracturing fractures, natural fractures connected with them, and the surrounding matrix. During the process of shut-in, the fracturing fluid in the fracture is gradually imbibed into the matrix, displacing the crude oil in the matrix and realizing the whole utilization of the stimulated area by volume fracturing. The research results can provide technical support for the efficient development of shale oil reservoirs from the perspective of microscopic oil-water two-phase flow characteristics and macroscopic productivity evaluation.