江陵凹陷复1断块油气富集原因分析

Hydrocarbon Accumulation Factors of Fu I Fault Block,Jangling Depression

影响江汉西南缘油气富集的因素很多,其中尤其以工区内油气主要输导断层如谢凤桥断层、复兴场断层和南岗F3断层表现最为明显。谢凤桥、复兴场等断层对油气运移具有双重作用,早期主要起通道作用,后期则主要起封闭作用。后期封闭性的原因一是构造活动减弱,二是沿断层面发生的强烈矿化作用。这些断层的几何形态和产状对油气运移路径有决定性影响,凸面断层使流线汇集形成垂向的优势运移通道,而凹面断层则使流线向上发散,油气不易汇聚。复Ⅰ断块ES8井和ES4-1井油气富集区位于谢凤桥断层断面凸出部位,而采穴断块ES11-1井油气富集区则位于复兴场断层断面凸出部位,南岗1号断鼻位于南岗F3断层断面凸出部位,下步应积极探索沙市组上段盐间盐下目的层的含油气性。

In the southeastern margin of Jianghan oilfield, there are many factors affecting hydrocarbon accumulation,especially including Xiefengqiao Fault,Fuxingchang Fault and Nan’gang F3 Fault as the main conducting faults.For hydrocarbon migration,b oth Xiefengqiao and Fuxingchang faults act as not only a pathwaya t early stage but also a closed zone at later stage.The closed zonei s just caused by two reasons:one is tectonic activities becomingw eaker and weaker and another is strongly mineralization occurring along fault plane.Both geometric shape and occurrence off aults impact the migration pathway definitively.And a convexfult makes streamline accumulated to form a vertical and dominant migration pathway whereas a concave fault makes streamlined ispersed upward,as a result,hydrocarbon can not easily accumulate.In both ES 8 well and ES4-1 well of Fu I Fault Block,the hydrocarbon accumulation area is situated at a bulged position off ault plane in Xiefengqiao Fault.In addition,in ES11-1 well ofC aixue Fault Block,the accumulation area is located at a bulgedp osition of fault plane of Fuxingchang Fault.And Nangang 1 Fault Nose is located at a bulged position of fault plane of Nan’gang F3 Fault.