水力压裂诱发地震活动中的b值时空异质性及其应用  

SPATIOTEMPORAL HETEROGENEITY AND APPLICATION OF b VALUES IN HYDRAULIC FRACTURING INDUCED SEISMICITY

作　　者：姜丛 蒋长胜[1] 尹欣欣 王蕊嘉 翟鸿宇 张延保 来贵娟[1] 尹凤玲[1] JIANG Cong;JIANG Chang-sheng;YIN Xin-xin;WANG Rui-jia;ZHAI Hong-yu;ZHANG Yan-bao;LAI Gui-juan;YIN Feng-ling(Institute of Geophysics,China Earthquake Administration,Beijing 100081,China;Gansu Earthquake Agency,Lanzhou 730000,China;Department of Earth and Space Sciences,Southern University of Science and Technology,Shenzhen 518055,China)

机构地区：[1]中国地震局地球物理研究所,北京100081 [2]甘肃省地震局,兰州730000 [3]南方科技大学,地球与空间科学系,深圳518055

出　　处：《地震地质》2022年第5期1333-1349,共17页Seismology and Geology

基　　金：国家科技基础资源调查专项(2018FY100504);中国地震局地球物理研究所基本科研业务专项(DQJB20X11)共同资助。

摘　　要：诱发地震及其灾害风险对非常规油气资源开发和废水回注等新型工业活动的顺利实施存在严重威胁,并早已引发社会各界及相关科研人员的广泛关注,由此也产生了许多需要进一步研究且亟待解决的科学问题。震级-频度分布(FMD)是描述地震活动的重要内容,对诱发地震的b值开展系统研究有助于揭示区域应力累积状态、地下构造特征以及诱发地震危险性。文中系统梳理了近十年来国内外工业开采水力压裂诱发地震b值的数值大小、时空异质性、物理机制解释、受影响因素、应用现状等相关的研究进展;归纳了前人发现的可能影响b值大小的因素,包括原位应力场、断层几何参数、断层成熟程度、震源深度等客观因素,以及注液体积、注液速率等由具体施工情况引起的孔隙压力大小变化的主观因素;总结了前人提出的包括孔隙压力控制论、原位差应力大小控制论、最大剪应力方向控制论、地质条件非均匀性决定论等多种可能的物理机制。厘清其中已取得的共识性认识、争议科学问题后,我们认为诱发地震b值或许可以成为判断储层改造效果、储层应力状态以及诱发地震灾害风险防治的入手点之一。文中对水力压裂诱发地震b值特征的总结分析可为从事新型能源开发、地震安全监管和科学研究领域的企业、管理人员及科学研究人员提供科学参考。Induced earthquakes and the corresponding seismic risk are rising concerns for the smooth implementation of new industrial activities such as the exploitation of unconventional oil and gas resources and has attracted broad attention from both the public and academia.As a result,many associated scientific problems need to be further examined.The magnitude-frequency distribution(FMD)is fundamental to seismicity characterization,where systematic study of b values for induced earthquakes could reveal the regional accumulated stress,subsurface structural characteristics,as well as seismic risks of induced seismicity.In this study,we systematically reviewed the values,spatial-temporal heterogeneity,physical mechanism,dominating factors,as well as the application status of b values on hydraulic fracturing induced earthquakes in the past ten years.Multiple case analysis shows that the b value varies over a wide range(0.6~2.9)and exhibits large spatiotemporal heterogeneity.Felt earthquakes are often preceded by decreased b values and often occur in the regions with relatively low b backgrounds.In addition,fault activation or felt induced earthquakes are often accompanied by b values less than 1.0,despite that b>1.0 are commonly observed in the process of fracture expansion.Thus,the b value is promising for estimation of the state of faults(i.e.,maturity and criticality).This study further assessed the factors that may affect b values,including objective factors such as in-situ stress field,fault geometry,fault maturity and focal depth,as well as subjective factors associated specific construction conditions,such as injection volume and injection rate.We then summarized multiple possible physical mechanisms,including the pore pressure,in-situ differential stress,maximum shear stress,and the non-uniformity of geological conditions.Although the discussed factors and physical mechanisms imply the multiple complexities associated with the b value that may challenge the effectiveness of its utilization,the b value remains a pre

关 键 词：水力压裂 诱发地震 时空异质性 B值 地震危险性分析 

分 类 号：P315.2[天文地球—地震学]