塔里木盆地和田古隆起对奥陶系油气成藏的控制作用

Control of Hetian Paleo-Uplift on Hydrocarbon Accumulation of Ordovician,Tarim Basin

和田古隆起作为塔里木盆地三大古隆起之一,随着勘探程度的加大,古隆起演化及其对油气成藏控制作用的研究尤显不足.基于对构造、锆石定年、油气包裹体等资料分析,揭示和田古隆起经历了多期构造叠加改造阶段,并控制了寒武系烃源岩的生排烃、奥陶系储层的形成和油气的运聚.在加里东中期-海西早期,和田古隆起控制了奥陶系碳酸盐岩储层的发育;玉北1井于奥陶系鹰山组风化壳中油包裹体成熟度资料表明,鹰山组风化壳存在至少两次油气充注;在加里东晚期-海西早期,存在一期成藏,残留为沥青.烃类包裹体以及与其共生的气液两相盐水包裹体均一温度处于100~110℃,结合埋藏史判定包裹体捕获时间为海西晚期.海西晚期,和田古隆起进入埋藏阶段,下伏寒武系烃源岩此阶段达到生烃高峰,奥陶系圈闭定型,油气沿不整合及断裂运移充注,在和田古隆起高部位及岩溶斜坡区有利于油气聚集,构成了和田古隆起的主成藏阶段;在喜山期,和田古隆起发生反转,奥陶系古油藏调整、改造,油气向北运移,麦盖提斜坡奥陶系构造枢纽带是油气成藏的有利区带,玉北地区中西部成为油气的有利靶区.

As the one of the three major paleo-uplifts, the evolution of Hetian paleo-uplift and its control on hydrocarbon accumulation are limited, especially with the development of exploration. Based on the analysis of structure, zircon and hydrocarbon inclusion, it is found in this study that Hetian paleo-high has undergone many phases of poly-cycle tectonic evolution and superimposition and reformation, and has controlled Cambrian source rock＇s generation and expulsion of hydrocarbon, Ordovician＇s reservoir, and the process of oil and gas accumulation. In the period from middle Caledonian to early Hercynian, Hetian uplift controlled development of Ordovician carbonatite reservoir. YB1 well acquire which in Ordovician Yingshan Formation＇ s crust of weathering, petroleum inclusion maturity,indicates two oil and gas fillings in Yingshan Formation＇s crust of weathering of carbonatite. In the period from late Caledonian to early Hercynian, there was the first phase of reservoir forming which has been destroyed and changed to pitch. Hydrocarbon inclusion and its associated gas-liquid two phase brine inclusions show temperature 100-110 ℃. Combined with the burial history, inclusion capture time is late Hercynian. In late Hercynian period, Hetian uplift burial, Cambrian source rock reached the peak period of hydrocarbon generation, Ordovician＇s entrapment got in to shape, oil and gas migration filled along unconformity and fault, and high position and karst slope zones facilitated oil and gas accumulation,which made up the main accumulation stage. In Himalayan period, Hetian palaeohigh reversed, Ordovician paleo-reservoir adjusted and remoulded, oil and gas migrated northward. The structural pivot positions, in Markit slope of the Ordovician, are oil and gas accumulation zones. Midwest of the Yubei is advantageous target area for oil and gas.