鄂尔多斯盆地林镇地区延长组长2沉积微相与油气分布

鄂尔多斯盆地林镇地区处于伊陕斜坡西南部,在长2沉积期研究区内发育辫状河三角洲前缘亚相沉积,沉积微相主要为水下分流河道、水下分流河道间、河口坝和远砂坝,物源主要来自北东和南西两个方向.林镇地区长2油藏的分布与沉积相关系密切,油藏主要分布于水下分流河道末端和河口坝的混合区,以及水下分流河道的侧缘,另外在远砂坝区也有少量油藏分布.区内长2期的辫状河三角洲前缘亚相沉积环境控制了长2储集层岩性的横向变化,同时区内长2地层普遍发育低幅度鼻状构造隆起,因此在构造圈闭条件和岩性圈闭条件共同作用下形成构造—岩性复合油藏.

Characteristics of the Sedimentary Microfacies and the Oil and Gas Distribution of Chang 2 Reservoir of Yanchang Formation in Linzhen Area, Ordos Basin

Linzhen area is situated in the southwestern Yi-shan slope of the Ordos Basin with the braided river delta front subfacies at Chang 2 Formation.The front subfacies of braided river delta of this area can be further divided into four types of sedimentary microfacies: underwater braided distributary channel,underwater distributary interchannel,river-mouth bar and distal bar.And the provenance mainly comes from northeast and southwest directions.Chang 2 reservoir of Linzhen area has close relationship with depositional facies.The joint zone of river-mouth bar,the end of underwater distributary channel,and the lateral distributary channel,are the distribution of reservoirs.Meanwhile,there are few reservoies in the area of distal bar.Owning to the lithology of reservoir bed in Chang 2 reservoir lateral changes in control of the sedimentary environment of the braided river delta front,and nose structure uplifts general development in the strata of Chang 2 reservoir,the structural-lithologic traps were formed in the interaction of the structural traps and the lithologic traps.