西湖凹陷中央反转构造带圈闭油气充满度差异性原因分析  

Analysis on the oil and gas fullness difference of the Central Inversion Tectonic belt of Xihu sag in East China Sea basin

作　　者：高伟中 谭思哲 田超 高顺莉 孙鹏 GAO Weizhong;TAN Sizhe;TIAN Chao;GAO Shunli;SUN Peng(CNOOC China Limited,Shanghai Branch,Shanghai 200335,China)

机构地区：[1]中海石油(中国)有限公司上海分公司

出　　处：《中国海上油气》2019年第3期20-28,共9页China Offshore Oil and Gas

基　　金：“十三五”国家科技重大专项“东海深层低渗-致密天然气勘探开发技术(编号:2016ZX05027)”;中海石油(中国)有限公司科技联合攻关项目“宁波27-1构造再评价关键问题攻关(编号:2018OT-KT-KY-LH-01)”部分研究成果

摘　　要：对西湖凹陷中央反转构造带生、储、盖、圈、运、保等石油地质条件进行了分析,结果表明西湖凹陷中央反转构造带中北部5个背斜油气藏油气充满度存在差异,变化范围是20%~100%,纵向上花港组H5砂组以上层位充满度总体较高、以下层位充满度降低。5个构造位于同一含油气系统内,烃源为下部的平湖组,储层为花港组,区域盖层为花港组上段H1—H2层,以背斜圈闭为主,总体上具备相似的静态地质要素,是有利的含油气目标区。5个油气藏主要为两期成藏,分别为15~13Ma和6~5Ma,以第一期为主,圈闭均形成于玉泉组沉积期末,圈闭形成期、断裂活动期和油气充注期在时空上耦合关系良好。断裂活动强度不同导致油气运移的输导能力不同,造就了中央反转构造带油气藏富集程度的差异,油源断层活动强度大,则油气运移条件好,圈闭油气充满度高。Analysis was conducted on the petroleum geological conditions (i.e.,generation-accumulation-caprock-trap-migration and preservation) of the Central Inversion Tectonic belt of Xihu sag,and the results show the different oil and gas fullness of five anticline reservoirs in the middle-northern parts of this tectonic belt (ranging from 20 % to 100 %). Longitudinally,the fullness of strata above H5 sand group in the Huagang Formation is generally higher,and that of the strata below this sand group is lower. The five structures are located in the same petroleum system,where the hydrocarbon source is the underlying Pinghu Formation,the storage is the Huagang Formation,and the regional caprock is the H1-H2 layers in the Upper Member of the Huagang Formation. Dominated by the anticline trap,they are the favorable hydrocarbon-bearing target zones,which generally exhibits similar static geological elements. These five oil and gas reservoirs were mainly developed in two stages,namely the 15~13 Ma and 6~5 Ma respectively,and the first stage plays the dominant role. All traps were formed at the end of the Yuquan Formation sedimentary period,and good time-spatial coupling relationship was maintained during trap formation,fault activity period and hydrocarbon charging periods. The different intensities of fault activities lead to the different conductivities of oil and gas migration,which results in the different enrichments of reservoirs in the Central Inversion Tectonic belt. If the fault activity of oil source is intensive,the oil and gas migration conditions will be good,and the oil and gas fullness of trap is high as well.

关 键 词：西湖凹陷 中央反转构造带 圈闭油气充满度 差异性 断裂活动强度 

分 类 号：TE122.3[石油与天然气工程—油气勘探]