An integrated insight into damage behaviors of induced cracks based on fractal characteristics

This article delves into the intricate world of hydraulic fracturing in shale gas reservoirs, focusing on the damage behaviors of induced cracks. Through an innovative approach, the study utilizes fractal characteristics of acoustic emission (AE) signals to monitor and analyze the propagation of these cracks. The research highlights the significant impact of injection rates and in-situ stress on the morphology and complexity of fracture networks. By conducting true triaxial hydraulic fracturing simulation tests on large-size shale samples, the study reveals distinct patterns of crack propagation under varying conditions. The evolution of induced fractures is categorized into three types: S-shaped growth, concave growth, and nearly linear growth. The fractal dimension of AE energy demonstrates a unique pattern of decreasing, fluctuating, and stabilizing, providing insights into the damage process. A correlation model is established, linking fractal characteristics with in-situ stress and injection rate, offering a predictive tool for optimizing fracturing designs and enhancing shale gas recovery. This comprehensive analysis not only advances our understanding of hydraulic fracturing but also provides practical guidelines for improving the efficiency of shale gas extraction.