Numerical simulation of hydraulic fracture propagation and stimulation effectiveness under in-Situ stress conditions

Based on the engineering background of 11,211 working face in Kekegai Coal Mine, this paper systematically studies the influence of key parameters on hydraulic fracturing effect in deep water-rich fractured thick coal seam and its optimal selection method. In this study, the true triaxial physical experiment and numerical simulation are combined, and the control effects of in-situ stress conditions, fracture pressure and interlayer interface on crack propagation behavior are analyzed emphatically. By constructing a three-dimensional stress field model and tracking the dynamic development process of cracks in real time with the help of acoustic emission monitoring technology, it is revealed that rock heterogeneity and stress distribution have a significant impact on fracture morphology: cracks in homogeneous rocks tend to develop smoothly and symmetrically, while complex branch cracks are easy to form in heterogeneous rocks. It is determined that 31.50–36.00 MPa is the optimal fracturing pressure range, which can ensure the fracturing effect and maintain the stability of surrounding rock structure. At the same time, it is found that moderate water injection rate (7.5–10.0 mL/min) is most beneficial to enhance interlayer connectivity and promote the formation of complex fracture network. The numerical simulation based on ABAQUS platform further verifies the stress redistribution law and crack propagation mode, which is consistent with the physical test results. This study provides important theoretical support and engineering guidance for the optimization of hydraulic fracturing parameters and the safe and efficient mining of coal seam under complex geological conditions.