高升油田高81块储层特征与含油气潜能

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。

RESERVOIR CHARACTERISTICS OF GAO NO.81 BLOCK AND ITS HYDROCARBON-BEARING POTENTIAL IN GAOSHENG OILFIELD

Gao No.81 Block in Gaosheng Oilfield of Liaohe basin is a monocline structure plunging towards east, and its confined by faults in three directions of northwest, southwest and southeast. The oil bearing strata is upper sub-member of E s4 which is mainly composed of fan -delta sediments, and its lower part( Dujiatai oil layer) is fan -delta front subfacies, consisting of underwater distributary watercourse, river mouth sandbar and interfluve microfacies.Whereas its upper part is chiefly made up of profan-delta subfacies which is interbedded by underwater distributary watercourse and river mouth sandbar of fan-delta front subfacies occasionally. Dujiatai oil layer can be divided into three sand groups, located at the upper part of the layer, No.1sand group has great change laterally, whereas No. 2 and No.3 group(below No.1) which are quite stable. The physical property of reservoir of No.3 sand group is \{believed\} to be the best, and with the greatest effective thickness of oil bearing on the average and oil bearing area is \{relatively\} large too. Therefore, No.3 sand group has made greatest contributions to reserving oil and gas in Gao No.1 Block. No.2 sand group, with small effective thickness of oil bearing on the average, lowest oil-water interface and largest oil -bearing area, has made less contributions to reserving oil and gas on the average than No.3 sand group. No.1. group tends to pinch out towards the higher part of the structure and has made a little contribution to reserving oil and gas due to its highest oil-water interface and smallest oil-bearing area.