摘要
尼日尔三角洲是世界上重要的含油气区,褶皱构造在其油气藏形成中起着重要作用。本文根据尼日尔三角洲的石油勘探资料,分析了褶皱的成因类型及不同类型褶皱的时序关系。尼日尔三角洲从陆上到海上可以划分为伸展带、过渡带和挤压带等三个构造带,它们组成一个完整的重力滑动构造体系。伸展带以逆牵引滚动背斜为特征,以背斜型圈闭为主,断块圈闭和岩性-地层圈闭为辅;过渡带为泥底辟相关的披覆褶皱,以背斜型圈闭为主,伴生泥底辟肩部和之间的砂岩尖灭圈闭;前缘挤压带发育逆冲断层相关褶皱,发育背斜和断背斜圈闭,背斜肩部和背斜之间发育砂岩尖灭圈闭。褶皱时间分别始于始新世、中新世以及中中新世—上新世。褶皱作用引起的地层剖面的缩短平衡了伸展作用引起的剖面的伸长。尼日尔三角洲与褶皱相关的圈闭,包括背斜、砂岩透镜体等富集了尼日尔三角洲绝大部分的油气。
The Niger Oelta is an important ail-hearing area in the world and folds played an imporlant role in its reservoir formation. By analyzing the exploration data, tire types of folds and the sequential relationships among various kinds of folds are discussed. The Niger l）eha can be divided into three tectonic behs, i.e., tailing extensional bell, transitional heh, and leading compressive belt from the onshore to the offshore, respeelively. The lhree belts conslitute an inlegral gravilational sliding system. Rollover anticlines oecured in the extensional beh and the dominanl traps were anlielines with fault blocks and litholngy-stralum traps. Mudstone diapir-related drape anticlines occurred in the transilional bell and the dominant traps were anliclines with sand bodies at the banks of mudstone diapirs and between the diapirs. Thrust faulting-related anticlines occm＇red in the leading comlpressive beh amt the main trails were anliclines with sand bodies at the banks of the anticlines and belween the anliclines. Folding began at the Eocene, Miocene, and middle Miocene-Pliocene for these three behs. respectively. The shortening caused by folding was accommodated by extension in the extensional beh. The fohting-related traps such as anticlines and sandstone lenses in various leclonic belts were the dominant Iraps thai accumulated almost all Ihe nil and gas reserves in the Niger Delta.
出处
《高校地质学报》
CAS
CSCD
北大核心
2013年第2期355-363,共9页
Geological Journal of China Universities
基金
国家科技重大专项(2011ZX05030-001-002)
国家自然科学基金项目(41172124)联合资助
