【摘要】 针对超临界CO₂压裂液在低渗页岩储层中存在气窜、裂缝扩展行为复杂的突出技术问题,提出了基于黏结力单元的超临界CO₂压裂数值模拟方法,研究了不同施工参数对CO₂压裂裂缝扩展行为,并从力学及微观化学层面揭示了超临界CO₂压裂液对低渗页岩裂缝的扩展机理。结果表明:压裂液黏度、压裂方位角和储层温压条件,均是影响储层裂缝扩展能力的关键因素;当方位角为30°时,裂缝扩展参数达到峰值。压裂液黏度、储层压力与裂缝扩展能力呈显著正相关关系,最大屈服（Mises）应力也会随上述条件增大而同步优化;储层温度的升高可大幅增加储层裂缝长度和宽度,但会加剧流体滤失。更多还原

【Abstract】 Aiming at the prominent technical problems of gas channeling and complex fracture propagation behavior of supercritical CO₂ fracturing fluid in low-permeability shale reservoirs, a numerical simulation method for supercritical CO₂ fracturing was proposed based on the bonding force unit. The effects of different operation parameters on fracture propagation behavior in CO₂ fracturing were studied, and the propagation mechanism of supercritical CO₂ fracturing fluid on low-permeability shale fractures was revealed from mechanical and microchemical perspectives. The results show that fracturing fluid viscosity, fracturing azimuth angle, and reservoir temperature-pressure conditions are the key factors affecting reservoir fracture propagation capacity. The fracture propagation parameters reach the maximum when the azimuth angle is 30°. Fracturing fluid viscosity and reservoir pressure have a significant positive correlation with fracture propagation capacity, and the maximum Mises stress is also optimized synchronously with the increase of the above parameters. The increase in reservoir temperature can greatly expand fracture length and width, but will aggravate fluid leakoff.更多还原