致密储层压裂真三轴物理模拟实验及裂缝延伸规律

Real triaxial physical simulation experiment of fracturing and the law of fracture extension in tight reservoir

通过真三轴物理模拟实验,研究不同逼近角、地应力状态下的含天然裂缝致密储层水力压裂缝延伸规律。以混凝土浇铸的大尺寸试样模拟致密储层;采用声发射仪实时监测试样破裂所发出的声波信号,并反演试样中水力压裂缝延伸形态;基于实验结果推导出涉及参数少和实用性高的水力压裂缝与人工裂缝相交判断准则。自然界的致密储层中广泛分布形态各异的天然裂缝,通过模拟含有天然裂缝的致密储层的水力压裂缝延伸规律更符合油气藏开发实际;有利于优选水力压裂作业参数。实验结果为致密储层水力压裂开采提供了一定的理论支持。

Through the true triaxial physical simulation experiment,the extension law of hydraulic fractures in tight reservoirs containing natural cracks under different approximation angles and stresses is studied.A large-sized sample cast of concrete is simulated as a dense reservoir and acoustic emission meter is used to monitor the acoustic signal generated by the rupture of the sample in real time,and the extension shape of the hydraulic fracture is simulated.The experimental results lead to the establishment of criterion for judging the intersection of hydraulic cracks and artificial cracks with fewer parameters and high practicability.The experiment simulates the widely distributed natural fractures in dense reservoirs in nature in order to obtain the hydraulic fracture propagation law for tight reservoirs containing natural fractures,which is in line with the actual development of oil and gas reservoirs,and to select the advantageous parameters for hydraulic fracturing operations.This research has provided theoretical support for the hydraulic fracturing exploration of tight reservoirs.