塔里木盆地超深层天然气成藏地质条件与资源潜力OA

Ultra-deep(burial depth≥6 000 m)exploration is a distinctive feature of petroleum exploration in the Tarim Basin.Since the implementation of the 14th Five-Year Plan,Tarim Oilfield Company has focused on exploration in ultra-deep new regions and new fields,achieving a series of major breakthroughs and discovering multiple new reservoir-cap rock combinations.This study deeply analyzes the geological conditions for ultra-deep hydrocarbon accumulation in continental oil and gas system of the Kuqa area,marine oil and gas system in platform-basin areas,and marine-continental transitional facies oil and gas system in piedmont areas of the Southwest Tarim.It is concluded that in the Tarim Basin,ultra-deep reservoir-cap rock combinations are either adjacent to or interbedded with source rocks,and trap formation occurred either earlier than or concurrently with the peak gas generation period of the source rocks.Therefore,the conditions for natural gas accumulation are favorable,leading to the development of multiple ultra-deep natural gas accumulation models.This study calculates the natural gas resources of the basin by using multiple methods.The in-place natural gas resources are 18.47×10¹² m³,and the ultra-deep in-place natural gas resources with a depth of≥6 000 m reach 13.40×10¹² m³.The ultra-deep natural gas is predominantly distributed in the Cretaceous-Jurassic strata of Kuqa area,Carboniferous-Permian strata in the piedmont area of Southwest Tarim,and the Ordovician-Cambrian strata in the platform-basin region.Favorable exploration zones for ultra-deep natural gas include the Kelasu Structural Belt,eastern segment of the Northern Structural Belt,Zhongqiu-Di'na section of the Qiulitag Structural Belt,periphery of the Kekeya area in the West Kunlun Thrust Belt,Wuqia Structural Belt in the West Tianshan Thrust Belt,eastern part of the Lunnan-Aman Transition Zone,and western margin of the Yingmaili Low Uplift.