喀麦隆里奥-德雷盆地构造发育特征及其对油气成藏的影响  

Structural characteristics and its influence on hydrocarbon accumulation in Rio del Rey Basin of Cameroon

作　　者：陈占坤[1] 陈瑞 佘刚[1] 袁井菊[1] CHEN Zhankun;CHEN Rui;SHE Gang;YUAN Jingju(Research Institute of Petroleum Exploration and Production,SINOPEC,Beijing 100083;United Energy(Beijing)Group Limited,Beijing 100016)

机构地区：[1]中国石化石油勘探开发研究院,北京100083 [2]联合能源(北京)有限公司,北京100016

出　　处：《长江大学学报（自然科学版）》2022年第4期13-20,共8页Journal of Yangtze University(Natural Science Edition)

基　　金：国家科技重大专项“重点盆地油气富集规律与目标评价”(2016ZX05033-002);中石化科技攻关项目“喀麦隆Rio de Rey盆地Nguti浊积岩油藏有利勘探目标评价”(P15166)。

摘　　要：里奥-德雷盆地发育泥岩底辟和生长断层2套断裂体系。盆地发育5条相互平行的南北向泥岩底辟构造带;底辟活动起始于渐新世,活跃于中新统,终止于上新世;泥岩底辟断裂体系的发育与因南大西洋拉张而产生的一系列北东-南西向区域走滑断层相关。生长断层断裂体系可被进一步划分为主动和被动2类,分别受水平拉张和垂向重力滑动控制,主动断裂起始于中新世,由北部斜坡带向南部泥岩底辟带推进,由此产生的小型断陷,形成了中-上新统地层的局部沉积中心;伸展背景下的被动断裂主要发育在盆地北部的缓坡区,从始新统至中新统均有发育,由于活动强度不大,对后期地层发育影响不大。以北东-南西向区域走滑断层为界,盆地可划分为南、北2个构造带,北部构造带包括内陆伸展构造带、中部过渡构造带和南部泥岩底辟带3个次级构造带;南部构造带则包括火山隆起带以及凹陷构造带2个次级构造带。盆地西南部的泥岩底辟区,长期处于构造斜坡之下,为烃源岩发育提供了最有利空间;泥岩底辟和生长断层在该区带同时发育,可有效沟通深部烃源岩和上覆沉积储层,是油气运聚的有利通道,综合评价认为此区带是盆地最有利的油气富集区带。Two fault systems including shale diapir system and growth-fault system are developed in Rio del Rey Basin.There are five paralleled N-S shale diapirs in Rio del Rey Basin,which initiated in Oligocene,thrived in Miocene,and ended in Pliocene.The development of shale diapir system is related to the activity of the regional NE-SW strike-slip faults which is the result of the south Atlantic rifting.The growth-fault system can be further divided into initiative and passive fault systems which are dominated by horizontal extension force and vertical gravity slip respectively.The initiative fault system started in Miocene and advanced successively from transitional belt in the north to shale diapirs belt in the south.The small fault depressions resulted from initiative fault system are the local depositional center of Miocene-Pliocene strata.The passive fault system in the extensional background is mainly developed in the gentle slope area in the north of the basin,which is active from Eocene to Miocene continuously.Because of the low activity intensity,the influence on the formation development in the later stage is limited.Rio del Rey Basin can be divided into two structural belts by regional NE-SW strike-slip fault.The northern structural belt is further divided into 3 sub-belts:inland extensional belt,central transitional belt,southern shale diapir belt;The southern structural belt is further divided into 2 sub-belts:volcanic uplifting belt and depression belt.Shale diapir belt in the SW of Rio del Rey Basin is always located in the downside of structure slope,which provides the best place for the development of source rocks.Both shale diapirs and growth-fault developed simultaneously in shale diapirs belt are the most favorable path for oil migration because they can connect the deep source rocks to overlying sedimentary reservoirs effectively.Comprehensively,the shalediapir belt is the best region of the basin for hydrocarbon accumulation.

关 键 词：里奥-德雷盆地 生长断层 泥岩底辟 构造单元 烃源岩 运移通道 油气成藏 

分 类 号：P618.13[天文地球—矿床学]