Variation of Permeability during the Pressure-Driven Process and Numerical Simulation Methods for Reservoirs.

Abstract

Water well pressure-driven reconstruction can replenish reservoir energy in a short time, significantly enhancing water injection capacity, forming effective displacement pressure differentials, and increasing oil well liquid production capacity. It is an effective means to resolve contradictions in developing low-permeability reservoirs. Addressing the complex fracture zones formed during pressure-driven processes involves conducting pressure-driven core experiments to ascertain the law of effective stress and permeability changes in target reservoirs, and establishing constitutive equations for dynamic permeability changes. The fitting coefficient of the equation to the experimental data reaches 0.99. The main fractures formed during the pressure drive control the direction of the modified zone. The simulation results show that the length of the main fractures ranges from 32 to 256 m, and a microfracture zone of 0 to 50 m is formed along the sides of the main fractures. Compared to conventional water injection pressure drives, the injection capacity is enhanced by 4 to 8 times. simulations show that employing dynamic permeability equations for pressure-driven reconstruction zones achieves good fitting of bottom-hole pressures under high injection conditions.