渤海湾盆地歧口凹陷南部高斜坡馆陶组不整合面及其油气成藏特征  

Characteristics of unconformity and its effect on hydrocarbon accumulations in Guantao Formation in the southern high slope of Qikou Sag,Bohai Bay Basin

作　　者：张洪[1] 赵贤正[2] 王居峰[1] 刘海涛[1] 姜文亚[2] 赵长毅[1] 张伟[2] Zhang Hong;Zhao Xian-zheng;Wang Ju-feng;Liu Hai-tao;Jiang Wen-ya;Zhao Chang-yi;Zhang Wei(Research Institute of Petroleum Exploration&Development,PetroChina,Beijing 100083,China;PetroChina Dagang Oilfield Company,Tianjin 300280,China)

机构地区：[1]中国石油勘探开发研究院,北京100083 [2]中国石油大港油田公司,天津300280

出　　处：《天然气地球科学》2019年第10期1465-1476,共12页Natural Gas Geoscience

基　　金：国家科技重大专项（编号：2016ZX05006-005-001）;国家科技重大专项（编号：2017ZX05008-006-002）联合资助;中国石油天然气股份有限公司大港油田分公司课题（编号：DGYT-2018-JS-542）

摘　　要：渤海湾盆地歧口凹陷南部高斜坡距离油源较远且油气主要是阶梯状运移,在馆陶组底部不整合面附近聚集成藏,形成该区的主体油藏。该区馆陶组底部不整合构成样式包括平行—削截型、平行—平行型2种类型,具下部半风化淋滤带和上部不整合面顶积层两层结构,岩性配置关系主要为上砂下泥型、上砾下泥型、上砂下砂型、上泥下泥型多样分布,而平行—削截型、上砂下泥型与上砾下泥型配置关系是油气分布的主体。立足不整合地质特征建模,开展三维模拟实验,结果表明:单一不整合油气藏,不整合上砂下泥型、上砾下泥型的岩性配置关系是成藏的关键要素;与断层共同作用的复合油气藏,具有断层关闭时不整合岩性—断层控藏和断层开启时不整合岩性—古地形控藏两大类成藏模式。不整合与断层、古地形的复合控藏作用,使得不整合面既存在聚集油气的作用,也存在运移油气的作用。高斜坡不整合油气藏的形成主要受控于不整合上下岩性配置关系,其次是断层启闭性和古地形构造背景,这一认识将为相似区块不整合油气藏研究与勘探提供有益的借鉴。The unconformity surface at the bottom of Guantao Formation,as the main reservoir in the southern high slope of Qikou Sag,Bohai Bay Basin,is far away from the oil source and the hydrocarbon is in step-migration mode dominantly.The macroscopical styles of this unconformity include the parallel-cutting type and the parallel-parallel type.Its two-layer microscopical structure consists of a lower semi-weathered leaching belt and an upper unconformity surface.The various lithology configurations around the unconformity are made up with four primary groups,being the upper sand and the lower mud,the upper conglomerate and the lower mud,the upper sand and the lower sand,the upper mud and the lower mud.The unconformity areas covered by the parallel-cutting macroscopical type,and by the groups of lithology configurations of the upper sand and the lower mud,the upper conglomerate and the lower mud,are the main one distributed for the hydrocarbon.On the basis of these features of the unconformity at the bottom of Guantao Formation,geological modelling was performed to reveal that as to the single unconformity reservoir,the key controlling elements of the accumulations are the two kinds of lithological configurations of the upper sand and the lower mud,and the upper conglomerate and the lower mud;and for the composite unconformity reservoir,two types of reservoir-forming modes are present,the unconformity lithology-fault controlled one when the fault is closed,and the unconformity lithology-paleotopography constrained one when the fault is open.As a result of the interplay of the unconformity surface and fault and paleotopography,this unconformity plays the role of transporting hydrocarbon and simultaneously has the use of accumulating oil and gas.The overall performance of binary composite functions controls the process of hydrocarbon migration and accumulation around the unconformity in the high slope.The formation of high-slope unconformity reservoirs is mainly controlled by lithology configurations between the upper and l

关 键 词：歧口凹陷 高斜坡 馆陶组 不整合面 油气成藏 

分 类 号：TE122.3[石油与天然气工程—油气勘探]