渤海辽北地区新生代断裂特征及其演变过程  

Structure and Evolution Analyses of the Liaobei Area of Bohai Bay Basin

作　　者：张江涛 郭涛 王冰洁 李虹霖 王茂桢 ZHANG Jiangtao;GUO Tao;WANG Bingjie;LI Honglin;WANG Maozhen(Tianjin Branch of CNOOC Ltd,Tianjin 300452,China)

机构地区：[1]中海石油(中国)有限公司天津分公司,天津300452

出　　处：《现代地质》2020年第6期1110-1118,共9页Geoscience

基　　金：国家科技重大专项(2016ZX05023-006)。

摘　　要：基于辽北地区三维地震资料和实钻井资料,对盆地结构特征和断裂体系进行精细刻画,并进一步结合区域地球动力学背景,对辽北地区(辽西凹陷北洼、鸳鸯沟洼陷、中央凸起南部倾末端和辽西凸起北部倾末端)新生代的构造演化过程进行了分析总结。结果表明:(1)主干控盆断裂的产状、活动性的变化使得辽北地区的盆地结构沿凹陷轴向自南部到北部存在差异:北部表现为东南断(陷)西北翘(倾)典型的简单半地堑断陷特征,中部受辽西2号断裂和辽西3号断裂控制,发育两个“半地堑”,共同构成了多米诺式半地堑系,南部辽西大断层正好切割盆地西部边界,表现为不对称的复杂“地堑”结构。(2)古新世—始新世断裂系统主要由NE向正断层组成,控制了盆地基底构造形态;渐新世则以NNE主干走滑断裂及其派生的次级断裂为主,且在主走滑带发育典型的张性或压性走滑转换构造;新近纪时期断裂体系以一系列次级断裂组合呈雁列式或羽状构造样式呈NNE展布为特征。(3)辽北地区新生代主要经历了三期构造演化阶段,分别是古新世—中始新世的强伸展弱走滑阶段、渐新世的强伸展强走滑阶段和新近纪的弱走滑拗陷阶段。Based on fine interpretations of 3D seismic data and drill-hole data from northern Liaoning,the structural characteristics and fracture system of the basin are characterized in detail,and integrated with the regional geodynamic framework of the northern Liaodong Bay(northern part of the Liaoxi,Yuanyanggou,and central depressions).Cenozoic tectonic evolution process of the southern tip of the bulge and the northern tip of the Liaoxi bulge was analyzed in detail.The results show that:(1)Changes in the occurrence and activity of the major controlling basinal faults make the basinal structure in northern Liaoning different from south to north along the depression axis:the northern part is characterized by the southeast fault(sag).The simple half-graben fault features are controlled by the Liaoxi No.2 and No.3 faults in the middle,and two half-grabens are developed to form a domino-type half-graben system.The southern Liaoning large fault cuts the western boundary of the basin,as manifested by an asymmetric complex graben structure.(2)Paleocene-Eocene fault system has mainly NE-trending normal faults,which controls the basin basement structure.In the Oligocene,the NNE-trending strike-slip faults and their secondary faults dominate,and the main strike-slip fault zone has developed a typical trans-tensional/-pressive transition structure.The Neogene fault system is characterized by a series of secondary fault combinations with an NNE en echelon pattern.(3)Cenozoic northern Liaoning experienced three stages of tectonic evolution,i.e.Paleocene-Miocene strong extension and weak strike-slip stage,Oligocene strong extensional strike-slip stage,and Neogene strike-slip stage.

关 键 词：渤海湾盆地 辽北地区 盆地结构 断裂特征 成因机制 

分 类 号：TE121.2[石油与天然气工程—油气勘探]