Research Of Oil And Gas Fluid Inclusion Of Mesozoic-Cenozoic Reservoir In Kuqa Region Of Tarim Basin

Kuqa region,located in the north of Tarim Basin,is a favorable zone of natural gas exploration.Aiming at reconstructing its pool-forming history,this study focus on the analyses of the hydrocarbon inclusions and saline inclusions hosted in the minerals of Cenozoic detrital rock strata,and the characteristics of petrology,structure,petrogenesis of this area.Based on the micro-thermometry analyses,hydrocarbon inclusions of Kuqa district can be classified into four stages: 1)Stage ? 1,yellow-brown fluorescent inclusions representing slightly mature,heavy oil;2)Stage ? 2,yellow or yellow-white fluorescent inclusions bearing mediate-mass,mature oil;3)Stage ?,blue fluorescent inclusions comprising mature-highly mature,light gas condensate,;4)Stage ?,black inclusion containing mature to highly mature natural gas.Combined with geothermal-burial history,the time of petroleum accumulation was determined by the micro-thermometry analyses of associated saline inclusions.All the four stages of hydrocarbon inclusions generated at Himalayan period.Actually,the formations of Stage ? 1 and Stage ? 2 inclusions occurred at early-middle Kangcun period(17-10 Ma)of Tietiary;Stage ? inclusions generated at late Kangcun period to early-middle Kuqa period(10-5 Ma);Stage? generated at late Kuqa period to Xiyu period of Quaternary.In general,petroleum system in Kuqa region is characterized by late and successive accumulation.The target area consists of three blocks: the eastern section(yiqikelike structural belt),the central section(Kelasu structural belt);the western section(Wushi sag).The distribution of these four stages inclusions in each part differs from each other.The central section only has only one stage of hydrocarbon inclusions(Stage ?),while Stage ?1 and Stage ?2 were found in the western section.Comparably,the eastern section has all the stages of inclusions.The structural blocks in Kuqa region are complex,and the natural gas there is unlikely from the same source.It is suggested that the gas in the Wushi sag comes from the lower Triassic source rocks;Yangxia Sag is inferred to be the main source ofthe yiqikelike structural belt in Kuqa east;and the lower Jurassic source rocks in Baicheng sag was supposed to be the provider of the Kelasu structural belt centered the Kuqa region.