珠江口盆地文昌A凹陷西部新生代断裂体系特征及演化过程  

Characteristics and evolution process of Cenozoic fault system in the western area of Wenchang A sag,Pearl River Mouth basin

作　　者：徐莅莅 范彩伟 李明 李辉 徐彬 程燕君 吴智平[1] XU Lili;FAN Caiwei;LI Ming;LI Hui;XU Bin;CHENG Yanjun;WU Zhiping(School of Geosciences,China University of Petroleum(East China),Qingdao,Shandong 266580,China;CNOOC China Limited,Zhanjiang Branch,Zhanjiang,Guangdong 524057,China;CNOOC China Limited,Hainan Branch,Haikou,Hainan 570312,China;College of Earth Science and Engineering,Shandong University of Science and Technology,Qingdao,Shandong 266590,China)

机构地区：[1]中国石油大学(华东)地球科学与技术学院,山东青岛266580 [2]中海石油(中国)有限公司湛江分公司,广东湛江524057 [3]中海石油(中国)有限公司海南分公司,海南海口570312 [4]山东科技大学地球科学与工程学院,山东青岛266590

出　　处：《中国海上油气》2024年第3期37-48,共12页China Offshore Oil and Gas

基　　金：中海石油(中国)有限公司科技攻关项目“文昌9/8区断裂侧封能力精细评价(编号:CCL2021ZJFN0200)”部分研究成果。

摘　　要：断裂体系发育是珠江口盆地文昌A凹陷西部地区新生代构造演化的重要表现形式。利用最新的三维地震资料,在精细刻画断裂体系静态特征的基础上,结合断层活动速率计算恢复断裂体系的动态演化过程,明确了文昌A凹陷西部地区新生代断裂体系发育的时空差异;并结合区域应力背景分析,探讨了断裂体系演化的成因机制,认为新生代以来三大板块间俯冲、碰撞及古南海俯冲消亡、新南海扩张共同造成的南海北缘区域伸展应力场顺时针旋转控制了断裂体系演化的时空差异。研究表明,文昌A凹陷西部地区断裂体系的发育演化经历了裂陷、拗陷与构造活化三个阶段,分别发育了NE(NEE)向、近EW向以及NW(NWW)向三组优势方向断裂,揭示了区域应力场伸展方向由NW—SE向到近SN向再到NNE—SSW向顺时针转变的过程;依据断裂的组合及沿承关系可将其划分为早期发育的NE向与后期发育的NW向两组交叠断裂带,NE向断裂带活动强度大、具有强烈伸展性质,NW向断裂带与基底先存断裂密切相关,活动强度弱、叠加一定走滑性质。文昌A凹陷西部新生代断裂体系演化的时空差异是对南海北缘区域应力场顺时针旋转的响应。Fault system development is an important manifestation of Cenozoic tectonic evolution in the western area of Wenchang A sag,the Pearl River Mouth basin.By using the latest 3D seismic data and finely characterizing the static characteristics of the fault system,combined with the calculation of fault activity rate to restore the dynamic evolution process of the fault system,the spatial and temporal differences in the development of the Cenozoic fault system in the western area of the Wenchang A sag are clarified.Based on the analysis of regional stress background,the genesis mechanism of fault system evolution is explored,and it is indicated that,the clockwise rotation of the regional extensional stress field at the northern margin of the South China Sea,caused by the subduction and collision between the three major plates,the subduction and disappearance of the ancient South China Sea,and the expansion of the new South China Sea since the Cenozoic era,controls the spatial and temporal differences in the evolution of the fault system.The results show that the development and evolution of the fault system in the western area of Wenchang A sag has undergone three stages of rifting,bending and tectonic activation,and three sets of predominantly NE(NEE),near-EW and NW(NWW)oriented faults have developed respectively,revealing the process of clockwise shift of the regional stress field extension from NW-SE to near-SN to NNE-SSW directions.Based on the combination and along-bearing relationship,it can be divided into two groups of overlapping fault zones:the early developed NE-oriented fault zone with strong activity intensity and extension property,and the later developed NW-oriented fault zone with low activity intensity and superimposed with certain slip nature,which is closely related to the pre-existing basement faults.The temporal and spatial differences in the evolution of the Cenozoic fault system in the western area of Wenchang A sag are a response to the clockwise rotation of the regional stress field at the nor

关 键 词：断裂体系 区域应力场 先存断裂 文昌A凹陷西部 珠江口盆地 

分 类 号：TE121.2[石油与天然气工程—油气勘探]