An improved fluid flow algorithm for hydraulic fracturing: Optimizing domain volume and crack pressure update strategies

With the widespread adoption of hydraulic fracturing technology in oil and gas resource development, improving the accuracy and efficiency of fracturing simulations has become a critical research focus. This paper proposes an improved fluid flow algorithm, aiming to enhance the computational efficiency of hydraulic fracturing simulations while ensuring computational accuracy. The algorithm optimizes the aperture law and iteration criteria, focusing on improving the domain volume and crack pressure update strategy, thereby enabling precise capture of dynamic borehole pressure variations during injection tests. The effectiveness of the algorithm is verified through three flow-solid coupling cases. The study also analyzes the effects of borehole size, domain volume, and crack pressure update strategy on fracturing behavior. Furthermore, the performance of the improved algorithm in terms of crack propagation rate, micro-crack formation, and fluid pressure distribution was further evaluated. The results indicate that while large-size boreholes delay crack initiation, the cracks propagate more rapidly once formed. Additionally, the optimized domain volume calculation and crack pressure update strategy significantly shorten the pressure propagation stage, promote crack propagation, and improve computational efficiency.