渤海湾盆地黄河口凹陷中洼断裂生长及其对新近系油气富集的控制作用  

Faults development controlled the Neogene hydrocarbon accumulation in the mid-Huanghekou Sag,Bohai Bay Basin

作　　者：王新宙 兰晓东[1] 刘豪[1] 杜晓峰 王清斌 WANG Xinzhou;LAN Xiaodong;LIU Hao;DU Xiaofeng;WANG Qingbin(School of Ocean Sciences,China University of Geoscience,Beijing 100083,China;Tianjin Branch of CNOOC,Tianjin 300452,China)

机构地区：[1]中国地质大学(北京)海洋学院,北京100083 [2]中国海洋石油(中国)有限公司天津分公司,天津300452

出　　处：《海洋地质前沿》2022年第11期73-81,共9页Marine Geology Frontiers

基　　金：中央高校基本科研业务费项目“渤海湾盆地黄河口凹陷及周边新近系油气运移成藏特征及富集规律”(35842019026)。

摘　　要：黄河口凹陷是渤海海域重要的富烃凹陷,区域主要的烃源岩沙三段在明化镇组沉积时期开始大规模生排烃,此时研究区内断裂发育,活动强度较高,因此,断裂有效性分析是确定区域油气输导体系、判断油气输导运移成藏的重要研究内容。通过三维地震数据及钻井分析,对黄河口凹陷中洼断裂分布、活动性及生长演化进行了系统的分析,结合区域烃源岩分布及钻井油气分布特征,总结断裂对新近系油气富集的控制作用。研究表明,黄河口凹陷中洼断裂活动生长具有“先变弱再变强”的特征−从沙河街组沉积时期到馆陶组沉积时期断裂活动强度逐渐减弱,断裂活动区域逐渐缩小;明化镇组沉积时,中洼断裂活动增强,区域内断裂全面活跃。研究区早期断裂多以长度短、断距小为特征;晚期洼陷中心联结组合形成大型断裂,油源断裂沟通源储,大部分油气沿着断裂运移至浅层馆陶及明化镇组砂体中,再向两侧砂体构造高部位运移,而南部缓坡带和北部陡坡带因为断裂活动速率不同而具有不同的油气聚集特征;南部缓坡带断裂晚期活动速率不高,能够对油气进行有效封堵,自深凹而来的油气沿着砂体构造脊在缓坡带馆陶及明化镇组砂体中聚集成藏;而北部陡坡带晚期断裂活动速率高,油气在断裂附近合适的明化镇组浅层圈闭中成藏。Huanghekou Sag is an important hydrocarbon-rich sag in Bohai Sea and can be divided into West-,Mid-,and East-Huanghekou sags.The source rocks of the third member of Shahejie Formation in the Mid-Huanghekou sag began to generate and expel hydrocarbons on large scale during the sedimentary period of Minghuazhen Formation.The analysis of active faults and their impact on the Mid-Huanghekou sag evolution is important to un-derstand the regional hydrocarbon migration and accumulation.Based on 3D seismic and drilling data analyses,the distribution,activity,and growth evolution of the faults in the Mid-Huanghekou sag were systematically ana-lyzed.Combined with the distribution characteristics of regional source rocks and oil-gas resources,the con-trolling effect of faults on hydrocarbon accumulation in the Neogene was summarized.The study shows that the development of faults in the mid-Huanghekou sag is characterized by“weakening first and then strengthening”.From the deposition period of Shahejie Formation to the deposition period of Guantao Formation,the intensity of fault activity gradually decreased and the fault activity area gradually shrank.During the deposition of Minghuazhen Formation,the fault activity was enhanced and the faults were fully active in the region.In the early stage,faults were small-sized;and in the late stage,they developed and merged into large ones in the central area of the sag,forming network of active faults-source rocks-reservoirs.Most of oil and gas migrated to the sand bod-ies of shallow facies of the Guantao and Minghuazhen Formations along active faults,and further to the both sides the structural highs of reservoirs.The north and south secondary structures have different hydrocarbon accumula-tion characteristics.In the southern gentle slope zone,the fault activity rate is small in the late stage,which effect-ively favored the sealing of the oil and gas,and finally formed large-scale oil-gas accumulation in the sand body along structural ridge.In the northern steep slope zone,the

关 键 词：断裂生长 新近系 油气 成藏控制 黄河口凹陷中洼 

分 类 号：P744.4[天文地球—海洋科学]