塔中地区古生界油气输导体系与油气运聚模式

CARRIER SYSTEM AND PATTERNS OF HYDROCARBON MIGRATION AND ACCUMULATION IN PALEOZOIC IN TAZHONG AREA

塔里木盆地中部地区古生界存在砂岩输导层、不整合输导层、碳酸盐岩深埋藏岩溶型输导层和断层输导层等多种输导层类型,它们在空间上构成了不同的输导结构样式,从而决定了塔中地区不同层系油气藏的类型和油气运聚特点。在石炭系、志留系、泥盆系地层中发育砂层、不整合输导层,油气以横向运聚为主,主要形成背斜和地层岩性油气藏。在奥陶系地层中发育2种运聚模式:①断层垂向输导、不整合侵蚀岩溶带横向汇聚的运聚模式;②碳酸盐岩内幕岩溶带自生自储运聚模式,形成古潜山型和内幕溶蚀型岩性地层油气藏。

Various kinds of carrier beds, such as sandstones, unconformities, karst in deep buried carbonate and faults, are developed in the Paleozoic in Tazhong area (the central part of the Tarim basin), and they consist of different carrier bed arrangements in space, thus control the types of reservoirs and the features of hydrocarbon migration and accumulation in different series of strata in Tazhong area. In the Carboniferous, Silurian and Devonian, sandstone and unconformity carrier beds are developed and anticline and stratigraphic-lithologic reservoirs are mainly formed through lateral migration and accumulation of hydrocarbons. While in the Ordovician, there are two patterns of hydrocarbon migration and accumulation: vertical migration through faults and lateral accumulation through unconformities and karst zones; ②self-generation and self-accumulation in internal karst zone of carbonate, leading to the formation of lithologic-stratigraphic reservoirs of buried hill type and internal dissolution type.