东濮凹陷庆祖集地区断裂对油气成藏控制作用浅析

庆祖集地区位于东濮凹陷西部斜坡带,发育NNE向、NE向和NW向3组张性正断裂系统,其中自西向东发育的五星集、石家集和长垣3条NNE向东倾基底大断裂系统是该区的主要断裂系统,将庆祖集地区分割成3个NNE向斜列式断阶结构,即Ⅲ台阶、Ⅱ台阶和Ⅰ台阶,Ⅱ台阶和Ⅲ台阶受断层控制,形态变化较大。3组断裂对油气成藏的控制作用存在明显差异。通过对主要断裂控制地层发育、沉积体系、烃源岩演化作用的分析,结合油藏发育特征,指出庆祖集地区具NNE向断裂控制不同台阶之间油气富集规模、NE向断裂控制各台阶内部局部构造油气富集程度、小断层控制局部构造内油藏分块性的断裂控油规律,并据此提出庆祖集南部地区为下步有利勘探区带,对地质条件类似地区的勘探有一定借鉴意义。

Control of fracture system on hydrocarbon pooling in Qingzuji Region of Dongpu Depression

Qingzuji Region is located at the west slope belt of Dongpu Depression,developing NNE,NE and NW trending extensional normal fracture systems,among which the east dipping basal fracture systems with NNE trending developed in Wuxingji,Shijiaji and Changyuan from west to east are the dominant fracture systems,which divide Qinzuji Region into three NNE trending diagonal faulted steps,namely the third step,second step and first step.The second step and the third step are controlled by faults.So they have greatly changed in shape.Three fracture systems have obviously different effect on hydrocarbon pooling.This paper analyzes the strata development,sedimentary system and evolution of hydrocarbon source rock controlled by the main factures.Combined with reservoir development characteristics,it also points out that Qingzuji Region has the oil-controlling laws that the NNE trending fracture systems controlled the oil reservoir enrichment scale among different steps,the NE trending fracture systems controlled the oil reservoir enrichment extent of the local structure within every step and the small scale faults controlled the oil reservoir partitioning within every local structure.Based on this,the next favorable exploratory zone in the south of Qingzuji Region is proposed,which can provide a reference for exploration of the areas with similar geologic conditions.