东海陆架盆地丽水-椒江凹陷构造演化特征及其与油气成藏的关系  

Structural evolution characteristics and their relationship with hydrocarbon accumulation of Lishui-Jiaojiang sag in East China Sea Shelf Basin

作　　者：郭刚 吴斌 张晓庆 廖计华 GUO Gang;WU Bin;ZHANG Xiaoqing;LIAO Jihua(CNOOC Research Institute Ltd.,Beijing 100028,China)

机构地区：[1]中海油研究总院有限责任公司,北京100028

出　　处：《大庆石油地质与开发》2024年第5期32-41,共10页Petroleum Geology & Oilfield Development in Daqing

基　　金：中国海洋石油集团有限公司“十四五”重大科技项目“中国近海新区新领域勘探技术”(KJGG2021-0300)。

摘　　要：东海陆架盆地丽水-椒江凹陷经历了复杂的构造运动过程,目前已发现多个含油气构造,但仍未取得大规模商业油气发现,油气勘探未能突破的主要原因在于对其构造演化特征认识不清。基于最新采集的三维地震和钻井资料,通过断裂特征的精细刻画、平衡剖面恢复、已钻井地球化学特征分析等方法,对丽水-椒江凹陷的构造演化特征及其与油气成藏的关系进行了深入分析。结果表明:丽水-椒江凹陷主要发育3套断裂系统,包括深部断裂系统、浅部断裂系统和贯穿断裂系统,控制了凹陷整体东断西超,内部南北分区东西分带的构造格局;凹陷演化共经历4个阶段,包括晚白垩世—古新世断陷期、始新世初期坳陷期、始新世末期—渐新世抬升剥蚀期以及新近纪—第四纪沉降期,不同断裂系统形成于不同演化阶段,并对凹陷结构具有差异控制作用;断陷期发育的灵峰组厚层泥岩阻挡了油气的垂向运移,且深部断裂与浅部断裂在纵向上各自独立,互不连通,油气垂向运移不畅,限制了油气在烃源岩及邻近层位成藏,确定了丽水-椒江凹陷“近源下洼”的油气勘探方向。研究成果可为丽水-椒江凹陷的油气勘探提供基础理论支撑。Lishui-Jiaojiang sag in East China Sea Shelf Basin has experienced complex structural movement.At pres-ent,several oil and gas bearing structures have been discovered,but without large-scale commercial discoveries.Main reason for the failure of oil and gas exploration is unclear understanding of structural evolution characteristics.Based on newly acquired 3D seismic and drilling data and by means of fine characterization of fault characteristics,balanced section restoration,and geochemical characteristics analysis of drilled wells,a thorough analysis is con-ducted on structural evolution characteristics and their relationship with hydrocarbon accumulation in Lishui-Jiaoji-ang sag.The results show that 3 sets of fault systems mainly develop in Lishui-Jiaojiang sag,including deep fault system,shallow fault system and penetrating fault system,controlling structural framework of the sag with overall east-faulted and west-overlapped and internally north-south zoned and east-west belted.The sag evolution has expe-rienced 4 stages including Late Cretaceous-Paleocene rift period,early Eocene depression period,late Eocene-Oli-gocene uplift and erosion period,and Neogene-Quaternary subsidence period.Different fault systems formed at dif-ferent evolution stages and have differential control on sag structure.Thick mudstone layer of Lingfeng Formation de-veloped during rift period blocks vertical hydrocarbon migration.Moreover,deep faults and shallow faults are verti-cally independent without connection,resulting in poor vertical hydrocarbon migration,restricting hydrocarbon ac-cumulation in source rock and adjacent layers,and thus defining oil and gas exploration direction of“near-source sag”in Lishui-Jiaojiang sag.The research provides basic theoretical support for oil and gas exploration in Lishui-Jiaojiang sag.

关 键 词：断裂特征 构造演化 油气成藏 丽水-椒江凹陷 东海陆架盆地 

分 类 号：TE121.3[石油与天然气工程—油气勘探]