塔里木盆地塔东地区下古生界碳酸盐岩储层特征与勘探领域

Characteristics and Exploration Domains of Lower Paleozoic Carbonate Reservoirs in Eastern Tarim Basin

塔里木盆地塔东地区下古生界碳酸盐岩勘探虽已获得突破,但储层类型和主控因素不清、有效储层分布规律不明一直是制约该区勘探领域评价和井位部署的瓶颈之一。基于露头、岩心、薄片、钻井、测试和地震等资料,综合地球化学分析数据,指出塔东地区发育5类储层,分别为奥陶系一间房组—鹰山组上段的灰岩礁滩溶蚀型储层、鹰山组下段—蓬莱坝组的溶蚀型白云石化储层、寒武系台缘丘滩白云岩储层、塔东低凸起上寒武统斜坡深水重力流型白云岩储层和上震旦统微生物丘滩白云岩储层。其中溶蚀型白云石化储层和台缘丘滩白云岩储层是塔东地区重要的储层类型,礁(丘)滩体和溶蚀作用是这两类储层发育的主控因素。在此基础上评价了两个现实勘探领域和三个风险勘探领域。

Exploration has made great progress in Lower Paleozoic carbonate rock in eastern Tarim Basin in recent years but confused reservoir types, controlling factors and spatial distribution regularity still are the technical problems so as to affect domain evaluation and well site deployment. Based on outcrops, cores and thin sections from 20 wells, and well logging and geochemical data, five types of reservoir are recognized in the eastern part of Tarim Basin, which include: (1) Ordovician Yijianfang-Upper Yingshan reef-shoal dissolved limestone reservoirs, (2) Ordovician Lower Yingshan-Penglaiba dissolved dolomitized reservoirs, (3) Cambrian platform margin bioherm-shoal dolostone reservoirs, (4) Upper Cambrian slope deep-water gravity-flow dolostone reservoir, and (5) Upper Sinian microbial bioherm-shoal dolostone reservoirs. The dissolved dolostone reservoirs and platform bioherm-shoal dolostone reservoirs are the most significant types of reservoirs in this area. Reef or bioherm-shoal and dissolution are the main controlling factors for reservoir development.Two present exploration domains and three risk exploration domains are evaluated, which provides technical support to petroleum exploration in this area.