巴西大坎波斯盆地裂谷体系及其对盐下成藏的控制作用  

Rift system and its controlling effects upon pre-salt hydrocarbon accumulation in Great Campos Basin,Brazil

作　　者：汪新伟[1] 孟庆强[2] 邬长武[2] 陶冶[2] 郭永强[2] 张云霞[2] 

机构地区：[1]中国石化集团新星石油有限责任公司,北京100083 [2]中国石化石油勘探开发研究院,北京100083

出　　处：《石油与天然气地质》2015年第2期193-202,共10页Oil & Gas Geology

基　　金：中国石油化工股份有限公司科技项目(P11063)

摘　　要：巴西东部海上大坎波斯盆地是中国油公司在巴西的主要投资目标之一。在前人研究的基础上,结合最新的勘探成果,厘定了盆地的构造演化阶段,剖析了盐下裂谷系的构造特征,并简要讨论了其构造差异对盐下成藏的控制作用。大坎波斯盆地的构造演化经历了晚三叠世—侏罗纪的克拉通内坳陷、纽康姆期—巴雷姆期的陆内裂谷、阿普特期的构造过渡期、阿尔布期—三冬期的初始拉张和坎潘期—上新世的大规模裂陷5个阶段。裂谷期的构造体系总体呈现倾向(东西)分带、走向(南北)分段的"斜向棋盘"格局。从倾向角度看,按基底埋深的高低可分为近岸低凹带、中部低凸带、近海低凹带和外部高地带4个构造带;从走向角度看,由于调节断层带的作用,形成了研究区内3个构造分段,即桑托斯、坎波斯与圣埃思皮里图,它们在构造线展布、裂谷形态与沉积厚度等方面存在差异。裂谷体系对盐下成藏的控制作用主要表现在烃源岩的成熟度、油气圈闭的类型及优质储层相带的分布3个方面。大坎波斯盆地的外部高地带与中部低凸带既是盐下油气运移的聚集带,又是优质储层的发育相带,因而是盐下油气勘探的有利区带。Great Campos Basin in offshore eastern Brazil has been one of the major investment attractions for Chinese oil companies .Based on previous studies and the latest exploration achievements in the basin ,the article identified its evolu-tion stages,analyzed its structural features ,and discussed the controlling effect of structural differences upon the formation of pre-salt accumulations .The basin had experienced five stages of tectonic evolution：intracratonic depression during the Late Triassic-Jurassic , intracontinental rifting in Neocomain-Barremian , rift-depression transition in the Aptian , initial opening in the Albian-Santonian and large-scale rifting in the Campanian-Pliocene.The overall tectonic system during the rifting stage can be likened to a “chessboard” featuring dipping direction（EW）zonation and strike（SN）segmentation. Along the dipping direction , the tectonic system consists of four belts in terms of depth of bedrock：nearshore concave belt,central low-convex belt,offshore concave belt and external high belt .Along the strike,the tectonic system is divided into 3 segments by the accommodating fault belt：Santos,Campos and Espírito Santos.They differ in tectonic line,rift shape and sedimentary thickness .The controlling effect of rift system upon the pre-salt accumulations in the basin is mainly expressed through source rock maturity;trap types and distribution of good reservoir rocks .The external high belt and central low-convex belt in the basin is considered as the most promising targets for pre-salt exploration .

关 键 词：构造演化 裂谷体系 盐下成藏 有利区带 大坎波斯盆地 巴西 

分 类 号：TE121.2[石油与天然气工程—油气勘探]