塔北隆起西部英买32潜山区岩溶储集层特征

Karst System and Reservoir Characteristics of Yingmai-32 Buried-Hill Area in Western Tabei Uplift,Tarim Basin

基于对塔北隆起西部英买32潜山区岩溶带发育规律的研究,建立了相关的岩溶发育模式。纵向上可以划分出2个旋回,其中表层岩溶带在白云岩潜山平均厚24.5m,在灰岩潜山稍薄。表层岩溶带之下划分出上部渗流岩溶带、上部潜流岩溶带、下部渗流岩溶带、下部潜流岩溶带和深部缓流岩溶带。横向上,表层岩溶带最发育的区域主要沿上寒武统白云岩潜山面分布,受相带和古地貌控制。岩溶系统与潜山油藏密切相关:白垩系卡普沙良群泥岩盖层+碳酸盐岩表层岩溶带与碳酸盐岩上部渗流岩溶带组合控制了潜山顶部油层的分布形态。在相对致密的渗流岩溶带的阻隔下,油气主要沿表层岩溶带内网状的洞、缝输导体系运移,在向潜山高位调整的过程中形成了准层状油藏。

Based on systemic study of karst development mechanism of Yingmai-32 buried-hill area in western Tabei uplift, the karst development model is developed, which can be divided into two cycles in vertical, including five superficial karst belts such as upper flow belt, upper groundwater flow belt, lower flow belt, lower groundwater flow belt and the deep tranquil flow belt. The superficial karst belt has a mean thickness about 24.5 m above the dolomite buried-hill area, but it becomes thinner in the limestone buried-hill area. Horizontally, the most developmental region of superficial karst belt is distributed along the top area of the Upper Cambrian dolomite buried-hill, controlled by lithofacies belt and ancient relief. It is concluded that the karst system is intimately related with the buried-hill reservoir. The distributed configuration of top buried hill reservoir is controlled by the assemblage of mudstone cap rock of Cretaceous Kapushaliang group, the superficial karst belt and the upper flow belt. Under the condition of cutting off by the relative tight upper flow belt, oil and gas migrate mainly along the netty crack-cavity system in the superficial karst belt. In the process of migration, they accumulate into the paleohigh of the buried-hill and form a karst quasi-layered reservoir.