摘要
为探究断裂对东海盆地西湖凹陷内反转背斜油气成藏的控制,寻找下一步有利勘探方向,选取典型的反转背斜G构造为研究对象,基于三维地震和钻井数据,通过构造解释、断层活动性分析、构造演化剖面、侧向封堵性评价等方法,对G构造的断裂特征及其圈闭形成、油气运聚和保存的控制作用进行深入分析。结果表明:G构造发育3组断裂,包括2条主控断层、组成似花状构造的次级断层以及浅部中新统内近EW向断层,主控断层形成于新生代早期、似花状构造次级断层形成于始新世平湖期、近EW向断层形成于中新世晚期的龙井运动。G构造主体表现为被断裂及火山机构复杂化的断背斜形态,先后受控于伸展正断、岩浆活动以及挤压反转等多期构造运动,最终在龙井运动末期定型;背斜高点的“花心”烃源断层断距小、活动性与主排烃期不匹配导致供烃能力弱;控圈断层在浅部侧向封堵性较差,同时背斜高点圈闭被近EW向断裂破坏;上述因素共同导致G构造在背斜高点勘探成效不理想。研究认为西湖凹陷内G构造等勘探不理想的反转背斜位于或者紧邻富烃洼陷、油气供给充足,仍具有良好勘探前景,背斜翼部“花瓣”断层发育区及未被近EW向断层破坏的次高点等区域的构造、构造—岩性复合圈闭是下一步勘探有利区。
To explore the control of faults on the formation of oil and gas reservoirs in inversion anticlines in the Xihu Sag,East China Sea Shelf Basin,and to explore potential exploration directions for the next step,this paper selects the typical inversion anticline structure G as a research target.Based on 3D seismic and drilling data,through structural interpretation and fault activity analysis,structural evolution profile and fault sealing analysis,the fault system’s characteristics,its controlling factor on traps formation,hydrocarbon migration and reservation were analyzed.The results show that,there are three groups of faults developed in structure G,including two main control faults,secondary faults forming flower like structure and roughly EW fault in the Miocene series.The main control fault was formed in the Early Cenozoic,the secondary fault of flower like structure was formed in the sedimentary period of Eocene Pinghu Formation,and the roughly EW fault was formed in the Longjing movement in the Late Miocene.The main body of the structure G is characterized by a fault anticline that complicated by faults and volcanic structures,which is controlled by multiple tectonic movements such as extensional faulting,magmatic activity,and compression inversion,and finally formed in the end of the Longjing movement;The“stamen”hydrocarbon source fault at the high point of the anticline has a small fault displacement,and its activity does not match the main hydrocarbon expulsion period,resulting in weak hydrocarbon supply capacity;The lateral sealing ability of the control fault is poor in the shallow part,and the high point of the anticline is destroyed by the roughly EW fault;The above factors collectively lead to unsatisfactory exploration results of the structure G at high points in the anticline.We believe that the inversion anticline in the Xihu Sag is located in or close to the hydrocarbon-rich sag,has sufficient oil and gas supply,and has good exploration prospects.The structural and structural-lithologic composite traps in the inversion anticline flanks and the sub-high point without EW-trending faults are favorable areas for further exploration.
作者
张晓庆
廖计华
李峰
赵洪
王军
ZHANG Xiaoqing;LIAO Jihua;LI Feng;ZHAO Hong;WANG Jun(CNOOC Research Institute Co.Ltd.,Beijing 100028,China;National Engineering Research Center of Offshore Oil and Gas Exploration,Beijing 100028,China;Shanghai Branch,CNOOC China Limited,Shanghai 200335,China)
出处
《天然气地球科学》
CAS
CSCD
北大核心
2023年第12期2136-2150,共15页
Natural Gas Geoscience
基金
国家重点研发计划(编号:2022YFF0800403)
中国海洋石油有限公司中国近海新区新领域勘探技术(编号:KJGG2021-0300、2023OT-KTKF02)联合资助.
关键词
背斜圈闭
反转构造
油气勘探
西湖凹陷
东海陆架盆地
Anticline trap
Inversion structure
Hydrocarbon exploration
Xihu Sag
East China Sea Basin
