Numerical simulation study on parameters impacting effective influence distance of pulse shock waves for well stimulation

Key words:  pulse shock wave  rock stress  effective influence distance  plug removal  numerical simulation

Abstract:

Numerical simulation was conducted to analyze the influence of energy storage, operation frequency, elastic modulus, and stress in rocks on effective repeated pulse shock waves for well stimulation. The simulation results show that, in the case with low energy storage, only plug removal can be achieved with no reservoir fracturing, while in the case with high energy storage, micro fractures can be generated that can induce reservoir fracturing and increase the formation permeability. With the increase of the number of operations, the effective influence distance of the shock wave can be increased continuously to a maximum value. After that, it remains constant. The rock stress has a great effect on the performance of the shock wave. With the increase of the rock stress, the effective distance of the shock wave decreases logarithmically, and when the rock stress is low and the elastic modulus is high, the effective distance increases as the number of operations increases. When the rock stress is high, the operation frequency and elastic modulus have little effect on the effective distance. The repeated strong shock wave can enhance plugging removal and increase production or injection of wells for the reservoir with large elastic modulus and low rock stress. In practical applications, the operation frequency can be optimized based on specific reservoir conditions.