滨里海盆地东南部盐构造与盐上油气成藏

Salt structures and hydrocarbon accumulation in up-salt zone of Pricaspian Basin Southeast

滨里海盆地阿斯特拉罕—阿克纠宾斯克隆起带和南恩巴隆起之间的区域,是一个重要的油气聚集区,油气成藏与盆地中的盐岩分布特征、盐岩的活动期次、盐构造发育、演化密切相关。滨里海盆地盐岩经历了多期的盐岩构造运动,形成了丰富多样的盐间盐上构造。根据形变盐体与上覆层之间的接触关系可以将盐构造分为整合型(非剌穿型)和不整合接触的底辟剌穿型两大类。来自盐下泥盆和石炭系烃源岩生成的油气在盐上丰富多样的圈闭中聚集起来形成了多种类型的油气藏。本区油气成藏的主控因素是盐窗的有效性以及对油气藏形成和保存有重要影响的盐体活动。

Pricaspian Basin is a typical salt basin.Hydrocarbon accumulation and distribution of salt rock of the basin,active time of salt rock,development and evolution of salt structure are closely related.Southeast of the basin,that is the area between Astrakhan-Aktyubinsk uplift and south-Enba uplift,is an important oil and gas accumulation zone.Salt rock of Pricaspian Basin has experienced multiphase tectonic activity and formed a variety of salt structures.Under the contact relationship between the deformed salt and the overlying salt layer,salt structures can be divided into two types:conformable contact and unconformable contact.There are many trap types in the Southeastern basin,including anticline,unconformity screened,fault screened,salt screened and pinchout trap.Through the analysis of structural evolution and sedimentary characteristics,up-salt formations can't generate hydrocarbon,oil and gas mainly migrated from sub-salt formations,passing through salt sides and salt windows.According to the spatial relationship between accumulation position of o&g and salt,and formations of o&g accumulation,reservoirs in up-salt layers can be divided into three categories:inter-salt,salt-eave and up-salt.