Exploring the Wenchuan earthquake fault through the accurate location of WFSD-4#Well using seismic reflection  

基于反射地震方法勘探深处汶川地震发震断裂科钻4号孔(WFSD-4)精确定位

作　　者：Feng Yang-Yang Yu Chang-Qing Li Hai-Bing Qu Chen Wu Chan Wang Qi Luo Su Huang Jin-Peng Rehana Ghazi 冯杨洋;于常青;李海兵;瞿辰;吴婵;王琪;罗愫;无(东华理工大学教育部核技术应用工程研究中心,江西南昌330013;中国地质科学院地质研究所,北京100037;南京大学地球科学与工程学院,江苏南京210023;中国石油东方地球物理公司吐哈物探处,新疆哈密839009;中国地质大学(武汉)地球物理与空间信息学院,湖北武汉430074;昆明理工大学国土资源工程学院,云南昆明650093)

机构地区：[1]Engineering Research Center of Nuclear Technology Application,Ministry of Education,East China University of Technology,Nanchang,JX,330013,China [2]Institute of Geology,Chinese Academy of Geological Sciences,Beijing,100037,China [3]School of Earth Sciences and Engineering,Nanjing University,Nanjing,210023,China [4]Tuha Division,BGP Inc.,CNPC,Hami,839009,China [5]Institute of Geophysics and Geomatics,China University of Geosciences,Wuhan,430074,China [6]School of Remote Sensing and Information Engineering,Wuhan University,Wuhan,430074,China [7]Faculty of Land Resource Engineering,Kunming University of Science and Technology,Kunming,650093,China

出　　处：《Applied Geophysics》2022年第4期473-484,603,共13页应用地球物理（英文版）

基　　金：supported by the“Deep Structure and Variation Characteristics of Fracture Shear Band of the Longmenshan Fault Zone”of the National Natural Science Foundation of China (No.42174123);the“Wenchuan Earthquake Fault Scientific Drilling”of the National Science and Technology Planning Project and the“3D Geological Mapping of Longmenshan Fault Zone”Project of the CGS China Geological Survey (No.1212011220265).

摘　　要：Deep drilling data on seismogenic faults that are obtained directly can help in understanding earthquake mechanisms and the resulting changes in deep structure and material composition.However,geophysical data are necessary to ensure that the planned borehole accurately drills through the target faults.In this study,the deep crustal structure of the Longmenshan fault is explored to obtain seismogenic fault characteristics of the Wenchuan earthquake.A scientific drilling project,Wenchuan Earthquake Fault Scientific Drilling No.4 Borehole(WFSD-4)is proposed with a borehole designed to drill through the north section of the fault zone while penetrating as many geological bodies and target layers related to seismogenic fault slip as possible.High-precision seismic exploration is then carried out to study the deep structure of the fault zone and achieve the scientific objective of the borehole.Two high-precision deep seismic reflection lines were arranged perpendicularly to the fault zone,and data were obtained through special acquisition schemes and processing methods.Finally,the surface position and drilling depth route of WFSD-4 are determined based on the interpretation results of seismic profiles.The seismic reflection method for site selection of the Wenchuan earthquake fault scientific drilling is proven feasible by comparing the interpretation with the actual drilling results,laying the foundation for further study on the deep structures of fault zones.通过深钻资料直接获取发震断层信息,有助于理解地震发生机理以及地震引起的深部结构和物质成分的改变。然而,如何确保钻探孔位位于最有利于穿过地震断层的位置,需要地球物理资料进行约束。为了探查龙门山断裂带北段的地壳深部结构,获取汶川地震的发震断裂特征,拟在北川-映秀断裂北段实施一口科学钻探(钻孔编号为WFSD-4)。钻孔选址要求钻穿北川-映秀断裂,同时尽可能多地穿透与地震断层滑动相关的地质体和目的层。基于该钻孔的科学目标,开展了针对断裂带深部结构的高精度地震探测工作,在垂直于断裂带的方向布设了两条高精度深反射地震测线。在数据采集和处理的过程中分别采取了针对断裂带特征的采集方案和特殊处理方法。最终,根据获得的剖面解译结果,确定了WFSD-4井的地表位置和钻深路线。通过与实际钻探结果进行对比,证明了反射地震方法应用于汶川地震断裂带科学深钻选址的可行性,为进一步研究断裂带深部结构奠定了基础。

关 键 词：Wenchuan earthquake site selection of drilling seismic reflection special processing method 

分 类 号：P315.2[天文地球—地震学]