摘要
震源机制是开展微地震资料解释的重要震源物理参数,对储层压裂开发的裂缝监测及其发育解释具有重要的实际意义.本文首先对共和盆地干热岩储层的地质背景和测试压裂阶段的微地震数据进行了介绍,然后阐述了基于HybridMT程序包的震源机制反演方法和基于主成分分析方法的优化求解思路,最后精细反演和解释了37个微地震事件(M_(W)0.80~1.69)的震源机制.震源机制类型以逆断层和走滑断层为主,双力偶分量占比较高表明裂缝以剪切破裂机制为主导,表明微地震活动多发生在先存的天然断层/裂缝上.P轴的优势方位和断层走向分别为近NE向和NE向及NW向,推测该深度的局部最大水平主应力方向与区域最大水平主应力方向基本一致.复杂的震源机制特征还与注水压力、局部地应力和地层高温等因素相关.本文首次尝试对共和盆地干热岩开采诱发微地震的震源机制开展深入研究,验证了微地震处理和裂缝解释的有效性,可为后续深部干热岩储层的裂缝监测和解释提供参考.
The source mechanism is an important source physical parameter for interpretating microseismic data and has significant practical values for reservoir microseismic monitoring and fracture propagation characterization.In this study,we introduced the geological background of the hot dry rock(HDR)reservoir in the Gonghe Basin and the microseismic data associated with the injection test,and then explained the source mechanism inversion method based on HybridMT package and the optimization approach based on the principal component analysis.Finally,the source mechanisms of 37 microseismic events(M_(W)0.80~1.69)were obtained and interpreted,which are predominantly characterized by thrust faults and strike-slip faults.The high proportion of double-couple(DC)components suggests that the fractures are dominated by the shear rupture mechanism,indicating that microseismic activity mostly occurred on pre-existing natural faults/fractures.The dominant strike of the P axes and the faults/fractures are orientated at approximately NE and NE/NW directions,respectively,suggesting that the direction of the local maximum horizontal principal stress at the depth is basically consistent with that of the regional maximum horizontal principal stress.The complex source mechanisms are also related to factors such as water injection pressure,local in-situ stress,and high temperature in the formation.We attempted to carry out in-depth research on the source mechanism analysis of microseismic events associated with HDR stimulation in the Gonghe Basin for the first time,verifying the effectiveness of microseismic processing and fracture interpretation.This study can provide a reference for future microseismic monitoring and fracture interpretation of deep HDR reservoirs.
作者
周雯
李磊
解经宇
赵争光
张浩
郑晶
ZHOU Wen;LI Lei;XIE JingYu;ZHAO ZhengGuang;ZHANG Hao;ZHENG Jing(Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring(Central South University),Ministry of Education,Changsha 410083,China;School of Geosciences and Info-physics,Changsha 410083,China;School of Resources and Geosciences,China University of Mining and Technology,Xuzhou Jiangsu 221116,China;4112 Geological Team,Bureau of Geology and Mineral Exploration and Development of Guizhou Province,Anshun Guizhou 561000,China;School of Mine Safety,North China Institute of Science and Technology,Sanhe Hebei 065201,China;Institute of Geomechanics,Chinese Academy of Geological Sciences,China Geological Survey,Beijing 100081,China;College of Geoscience and Surveying Engineering,China University of Mining and Technology–Beijing,Beijing 100083,China)
出处
《地球物理学报》
北大核心
2025年第9期3464-3476,共13页
Chinese Journal of Geophysics
基金
国家自然科学基金项目(42374076,42102353)
中南大学创新驱动计划项目(2023CXQD063)
湖南省自然科学基金优秀青年项目(2022JJ20057)
中国科协青年人才托举工程项目(2023QNRC001)资助.
