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辽河盆地高升油田高 81块为一东倾的单斜构造 ,其西北、西南、东南三面均为断层所限。其含油层为下第三系沙河街组第四段上亚段。沙四上亚段主要为扇三角洲沉积 ,其下部含油层段 (杜家台油层 )为扇三角洲前缘亚相 ,由水下分流河道、河口砂坝、河道间微相构成 ;上部以前扇三角洲亚相为主 ,前缘亚相的水下分流河道微相及河口砂坝微相时而穿插其间。杜家台油层可分为 3个砂层组 ,位于上部的Ⅰ砂层组横向变化大 ,其下的Ⅱ ,Ⅲ砂层组较为稳定。Ⅲ砂层组的储油物性最好 ,平均有效含油厚度最大 ,含油面积也较大 ,它对高 81块油气储量的贡献最大。Ⅱ砂层组平均有效厚度较小 ,但其油水界面最低 ,含油面积最大 ,对储量的贡献仅次于Ⅲ砂层组。Ⅰ砂层组向构造高部位趋于尖灭 ,且其油水界面最高 ,含油面积很小 ,对储量仅有少量贡献。
The Gao 81 oil-gas field in Liaohe Basin is an east-dip monoclinic structure with faults on the three sides of the northwest, southwest and southeast. The oil-bearing formation is the upper section of the fourth section of Shahejie Formation in the Lower Tertiary. The Upper Member of Upper Es4 is mainly composed of fan delta sediments, and the lower oil reservoir (Dujiatai Formation) is fan delta front subfacies composed of underwater distributary channel, estuary sand bar and inter-channel microfacies. The upper anterior fan delta The subfacies dominated the microfacies of the underwater distributary channel and the estuarine sand dam in the frontal subfacies. The Dujiatai oil layer can be divided into three sand layer groups, and the horizontal change of the sand layer Ⅰ in the upper part is large, and the sand layers in the Ⅱ and Ⅲ sand layers under it are stable. The oil-bearing properties of Group III sandstones are the best, the average effective oil thickness is the largest, and the oil-bearing area is also larger, which contributes most to the high-grade oil and gas reserves. The average effective thickness of Ⅱ sandstone group is smaller, but its oil-water interface is the lowest, its oil-bearing area is the largest, and its contribution to reserves is second only to that of III sand layer. The sandstone group tends to be extinct to the high part of the structure, and has the highest oil-water interface with a small oil-bearing area and only a small contribution to reserves.