射孔作业对孔道周围岩石损伤规律实验研究

Experimental Study on Failure Laws of Rock around Perforating Tunnel Caused by Perforation

利用高温高压射孔实验装置对水泥试样进行了加围压射孔实验,以研究射孔作业对其孔道周围岩石的破坏规律。结果表明:射孔作业对其孔道周围岩石会产生不同程度的损伤破坏,其破坏形式由近孔向外依次为压剪损伤区、拉伸损伤严重区、拉伸损伤衰减区;而随着围压的增加,拉伸损伤严重区范围会减小,裂纹数目减少,损伤程度降低。计算发现孔道周围岩石的渗透率较射孔前有明显增加。本实验结果将为科学分析压裂裂缝起裂规律打下了一定理论基础。

Experiment used logging HPHT perforating experiments on cement pressurization vessel perforation in order to study the failure laws of rocks caused by perforation. Experiment results showed that perforation caused rock damage with different levels around the perforating tunnel. There were three damage forms from the perforating tunnel to the outside： compression-shear damage zone, severe tensile damage zone,and tensile damage attenuation zone. As confining pressure increased,severe tensile damage zone decreased, the number of cracks increased and the degree of damage reduced. The subsequent calculation indicated that the permeability of rocks around perforating tunnel apparent increased after perforating. Experiment results lay a theoretical foundation for scientifically analyzing the laws of hydraulic fracture initiation.