镇泾地区延长组河流相砂体分布与圈闭形成的关系研究

鄂尔多斯盆地镇泾地区侏罗系地层以三角洲-湖泊沉积体系为主,研究区范围内主要发育主河道和部分分流河道砂体。研究区构造平缓,主要为单斜地层、在东南部存在大型鼻状构造。通过对主要储层段(长6、8油层组)砂体分布及与构造之间关系进行研究,分析砂体走向与构造线方向的关系认为在构造单斜地区,当两者相交时(交角β≠0)是形成圈闭的关键因素之一,在大型鼻状构造地区因构造线的弯曲与河道砂体组合可以形成圈闭。根据研究区砂体分布和构造线组合出4种地层-岩性及岩性圈闭。利用构造图与砂体分布图对主要储层段存在的圈闭确定出长6、8油层组10个层圈闭。

REASERCH ON THE RELATIONSHIP BETWEEN DISTRIBUTIONS OF FLUVIAL FACIES SANDBODY AND THE FORMATIOM OF TRAP,THE YANCHANG FORMATION IN ZHENJING REGION

The Jurassic stratum in Zhenjing region of Ordos basin is mainly of deltaic-lake sedimentary system. Main stream channel sand body and distributary stream channel sand body occurred in the area.The attitude of bedding in the area is gentle,reflecting basically a monocline feature.In the southeast of the area,there exists a large-scale nose-like structure. The relation between the distribution of the sand body of the main oil-bearing formation (Chang 6 and Chang 8 Formation) and the structure is studied in detail. Analysis of strikes of the sand body and the structures indicates that the intersection of the 2 strikes is a key factor in the formation of trap.The combination of curvature of structural lines in the locality of nose-shape structure with the sand body results in the trap formation.Accordingly,four types of stratigraphic-lithologic traps and lithologic traps are proposed and ten intra-formational traps in Chang 6 and Chang 8 Formation are determined.