鄂尔多斯盆地子长地区长2沉积特征

根据岩石类型及特征、颗粒磨圆度和接触方式、沉积构造等对鄂尔多斯盆地子长地区长2油层的沉积相进行了系统研究。研究显示:子长地区长2构造结构与陕北斜坡一致,发育近东西向的宽缓鼻状构造;储层岩性主要为细粒长石砂岩和岩屑长石砂岩;属于三角洲沉积体系,发育三角洲平原亚相,其微相类型主要有水上分流河道、陆上天然堤、沼泽微相,其中砂体主要发育在水上分流河道沉积微相带;研究区主要含油层位为长21-3和长22-1,含油区带大致呈北东南西向展布,储层物性好。

Sedimentary facies of Chang 2 in the Zichang area,Ordos Basin

The sedimentary facies of Chang 2 reservoir in Ordos Basin were studied systematically according to the types and characteristics of rocks,the degree of grain roundness and contact,and the sedimentary structure. The results show that the structure of Chang 2 in the study area is consistent with the slope of northern Shaanxi and develops a wide and gentle nose-like structure near the east-west direction. The reservoir lithology is mainly fine arkose and lithic arkose. It belongs to the deltaic sedimentary system and develops deltaic plain subfacies. Its microfacies types mainly include water-distributary channel,onshore natural embankment and swamp microfacies. The main oil-bearing reservoirs in the study area are Chang 21-3 and Chang 22-1,and the oil-bearing layers are distributed in the northwest,southeast and west direction,with good reservoir physical properties.