摘要
巴西陆上Solimoes盆地属克拉通盆地,其沉积组合和油气成藏非常特殊。文中重点研究盆地的形成演化及构造特征、沉积地层特征、石油地质特征,分析盆地成藏特征及成藏模式,确定成藏主控因素。盆地经历了多期构造运动,古生代经历了多次沉降,中生代抬升,新生代以挠曲沉降为主,构造样式以先正后逆的反转构造为特点。沉积地层以古生界为主,岩性组合复杂,包含了碎屑岩、碳酸盐岩、蒸发岩、冰碛岩及火山岩等多种岩石类型,层系之间均为不整合接触。主要烃源岩为上泥盆统页岩,总有机碳含量高,热演化程度高;主要储层为石炭系Jurua组砂岩;主要盖层为石炭系-二叠系蒸发岩,封盖能力强,生储盖配置好。盆地内构造圈闭发育,以背斜、断背斜为主。盆地成藏模式特殊,尽管烃源岩埋深较浅,却在火山岩侵入的烘烤作用下快速成熟并进入高成熟演化阶段——生气阶段;风成砂具有良好的储集性能,储层孔隙由于埋藏深度小而保留,不整合面和复活的基底断裂是油气运移的良好通道。断层相关的构造圈闭控制油气的聚集。
Onshore Solimoes Basin in Brazil is an intra-cratonic basin,being very special in its depositional succession and its hydrocarbon accumulation mechanisms.This paper focuses on summarization of the formation and evolution of the basin,its structure and depositional characteristics and its key petroleum geologic features,as well as analysis of hydrocarbon accumulation mechanism and the main controlling factor for accumulations.The basin has experienced multiple tectonic movements,including multiple subsidence during the Paleozoic,a shear stress dominated Mesozoic age,and flexure subsidence in Cenozoic.The deformation style features in change from early normal faulting to later inversion and thrusting.The deposits in the basin are mainly of Paleozoic age,and are complicated in lithologic assemblages,consisting of siliciclastics,carbonates,evaporites,glacial deposits,igneous,etc.All the sequences are in unconformable contacts.The major source rock is the Upper Devonian shale,with high TOC value and high degree of thermal maturity.The main reservoir is the Carboniferous Jurua sandstone.The main seal interval is the Carboniferous-Permian evaporites,which is good in sealing capacity.The source rock-reservoir-seal combination is favorable.The basin has well developed structure traps,which are mainly anticlines and faulted anticlines.The petroleum geology of the basin is special in that the shallowly buried source rocks have entered gas window due to igneous intrusion.Eolian sands have good reservoir quality,with well preserved porosity due to its shallow burial depth.The unconformities and reactivated basement-rooted faults serve as the major pathways for hydrocarbon migration.The accumulation of oil and gas is controlled by the fault-related structrual traps.
出处
《石油与天然气地质》
EI
CAS
CSCD
北大核心
2013年第3期363-369,共7页
Oil & Gas Geology
基金
中国石油天然气集团公司"九五"重点科技攻关项目(970211)
关键词
圈闭
储盖组合
构造演化
油气成藏
Solimoes盆地
巴西
trap
reservoir-cap combination
structural evolution
hydrocarbon accumulation
Solimoes Basin
Brazil
