蟠龙油田三叠系长2油组油气富集规律

PETROLEUM ACCUMULATION AND DISTRIBUTION LAW OF CHANG 2 FORMATION IN PANLONG OILFIELD ORDOS BASIN

鄂尔多斯盆地陕北斜坡为一平缓的西倾单斜,通常认为长2油藏的形成和分布主要受沉积相和优质储层控制,构造、裂缝等其他地质因素作用较弱。对陕北斜坡东部蟠龙油田长2油层组油气富集主控因素的研究表明,蟠龙油田长2油藏的形成和富集受沉积相带和优质储层、鼻状隆起背景、区域盖层与局部盖层、运移通道等多种因素控制,其中,鼻状隆起与局部盖层对长2油藏意义更为突出,鼻状隆起的围斜部位油藏最为富集,而局部盖层拓展了油层纵向分布范围。长2油藏类型复杂多样,除岩性油藏以外,以构造-岩性为主的复合油藏是该区长2油藏的主要类型。

The formation and distribution of Chang 2 accumulations in Yanchang Formation in the North Shanxi Slope are considered to be controlled by sedimentary facies and high quality reservoir.Other geological factors such as structure and fracture have a relatively weak effect on the formation of reservoir.The present study shows that the formation and enrichment of Chang 2 reservoir are subject to multiple factors such as:sedimentary facies,high quality reservoirs,the background of nose-shaped uplift,regional seal,local seal and migration pathway etc in Panlong Oilfield,among which the nose-shaped uplift and local cap rocks are the most important conditions for the formation and enrichment of Chang 2 reservoir because the periclinal structure of nose-shaped uplift is rich in hydrocarbon reservoirs and the local cap rocks expand the longitudinal distribution range of oil.Besides lithologic accumulations,structure-lithologic composite accumulations are the main types of the Chang 2 accumulations.