巴西桑托斯盆地盐下构造单元划分原则与方案刍议  

Discussion on the division of subsalt tectonic units of Santos Basin, offshore Brazil

作　　者：史卜庆 范国章 邵大力 王红平 赵俊峰 刘亚明[3] 左国平 王朝锋 杨柳 马宏霞 丁梁波 SHI Buqing;FAN Guozhang;SHAO Dali;WANG Hongping;ZHAO Junfeng;LIU Yaming;ZUO Guoping;WANG Chaofeng;YANG Liu;MA Hongxia;DING Liangbo(不详;Petro China Hangzhou Research Institute of Geology,Hangzhou,Zhejiang 310023,China)

机构地区：[1]中国石油国际勘探开发公司 [2]中国石油杭州地质研究院 [3]中国石油勘探开发研究院

出　　处：《海相油气地质》2021年第3期263-271,共9页Marine Origin Petroleum Geology

基　　金：中国石油天然气集团有限公司科技项目“海外深水、超深水油气勘探关键技术研究”(编号:2021DJ2403)资助。

摘　　要：桑托斯盆地历经早白垩世早期克拉通坳陷盆地、早白垩世早—中期裂谷盆地、早白垩世晚期至全新世大陆边缘盆地3个演化阶段,石油资源主要富集于裂谷盆地的生储盖组合中,目前的盆地构造单元划分方案不能够准确地反映裂谷期的构造格局。根据最新的重磁、地震、钻井、大洋钻探等基础资料,提出了桑托斯盆地盐下构造单元划分的新方案:(1)以晚断陷期主要断裂和沉积特征作为划分一级构造单元的依据,根据断裂分布结合晚断陷期沉积厚度600 m等值线确定隆起与坳陷的边界;(2)以晚断陷期次级断裂和沉积特征作为划分二级构造单元的依据,根据同沉积拉张断裂、二级走滑断裂及其调节断裂分布,结合晚断陷期和早坳陷期沉积厚度1 000 m等值线确定凸起和凹陷的边界;(3)将盆地划分为"二隆三坳"5个一级构造单元,包括西部坳陷、阿乌隆起、中央坳陷、卢苏隆起和东部坳陷,并进一步划分为38个二级构造单元。以裂谷盆地构造演化特征为主要依据划分的构造单元对未来油气勘探选区和资源评价具有重要意义。Santos Basin has experienced three evolution stages: Early Cretaceous craton depression basin, early and middle Early Cretaceous rift basin and late Early Cretaceous Albian-Holocene continental margin basin. Oil resources are mainly enriched in the source-reservoir-cap assemblage of rift basin. The current division scheme of basin tectonic units can not accurately reflect the tectonic framework of rift period. According to the latest basic data of gravity and magnetism, seism, drilling and ocean drilling, a new scheme for the division of subsalt tectonic units in Santos basin is put forward:(1)Taking the main faults and sedimentary characteristics in the late fault depression period as the basis for the division of primary tectonic units, the boundary between uplift and depression is determined according to the faults distribution and the isoline of sedimentary thickness of600 m in the late fault depression period.(2)Taking the secondary faults and sedimentary characteristics in the late fault depression stage as the basis for dividing the secondary tectonic units, the boundaries of bulges and sags are determined according to the distribution of synsedimentary tension faults,secondary strike slip faults and their regulating faults, combined with the1 000 m isoline of sedimentary thickness in the late fault depression stage and early depression stage.(3)The basin is divided into five primary structural units of"two uplifts and three depressions", including western depression, Aram-Uirapuru uplift, central depression, Lula-Sugar uplift and eastern depression, and further divided into38 secondary structural units. The tectonic units division based on the evolution characteristics of rift basins are of great significance for future oil and gas exploration and resource evaluation.

关 键 词：构造单元划分 盐下 裂谷盆地 桑托斯盆地 巴西 

分 类 号：P618.130.2[天文地球—矿床学]