中文摘要：

随着二氧化碳地质封存、深部地热开采、地下储气库建设、页岩气开发、二次驱油/驱气等工业应用的快速发展,与地下流体注入有关的诱发地震活动呈现一定的增加趋势.利用声发射实验观测油气田典型岩石在三轴压缩条件下变形破坏过程与声发射活动特征,对研究注水诱发地震过程有着重要意义.本文利用四川盆地现场采集的震旦系白云岩及页岩,采用实验室声发射技术观测研究岩石三轴压缩变形破坏过程中地震波速度等物性参数及声发射事件时空分布特征.实验结果表明：震旦系白云岩及页岩在变形破坏过程中均有一定的声发射活动.根据声发射定位结果,声发射主要集中在破坏前后的较短时间内,页岩的层理面为结构弱面,控制最终破坏面的形态及声发射特征.根据应力-应变结果,白云岩在压缩的后期阶段有一定的扩容现象,但页岩在整个压缩阶段均没有明显扩容现象.研究结果表明四川盆地较古老的白云岩及页岩具有脆性破坏特征,地下流体注入容易诱发微震活动,形成裂缝,有利于页岩气压裂开采.微震活动有利于监测裂缝的发生发展,但同时在页岩气开发及二氧化碳地质封存时应采取相应的预防控制措施进行安全合理的储盖层管理,避免灾害性诱发地震的发生.

英文摘要：

With rapid development of carbon dioxide geological storage,exploitation of deep geothermal energy and shale gas,construction of underground oil/gas reservoirs,and enhancedoil/gas recovery,the underground-fluid-injection（UFI）induced seismicity is widely observed.Such seismicity depends on the injection pressure,lithology of reservoir and trap,tectonic stress,and development of cracks.Research of the role of these factors on different scales is crucial to understand of the occurrence of UFI induced earthquakes.Investigation of mechanical properties of reservoir rocks under hydraulic conditions and triaxial compression from laboratory experiments can improve our understanding of the mechanism of UFI induced seismicity.The dolomite and shale are typical sedimentary rocks in the Sichuan Basin,China,which is known as a representative area with UFI induced seismicity in China.In order to make clear the geomechanical conditions of UFI induced seismicity,this paper presents some results of a triaxial compression laboratory study of the process of deformation and failure and the characteristics of acoustic emission（AE）in Sinian dolomite and shale collected from the Sichuan Basin.The experiments were performed in a high pressure vessel of a loading system.First,the confining pressure was increased slowly to 10 MPa,which is equal to the stress conditions existing at depth ~1km in the subsurface.Second,when the confining pressure was kept constant,the axial stress was increased at a constant rate of 2 MPa/min until the specimen fractured.The AE events were monitored by a high-speed multi-channel waveform recording system.In addition,the ultrasonic transmission measurement was periodically applied to monitor the P velocity and amplitude change induced by the confining pressure and axial stress during the process of loading.Finally,a 3DX-ray CT scanning was carried out for the broken specimen to reconstruct the fault geometry and the heterogeneous structure.The combination of strain-stress data and associated AE is use