Studies On Enrichment And Coexistence Of Various Energy Resources In The North Margin Of Qaidam Basin And Its Reservoir(ore)-forming System

Qaidam Basin is one of the three Large sedimentary basins in northwest China.The Jurassic sedimentary area roughly distributes in the north margin of Qaidam.After many years of exploration practice,there are not only conventional oil,conventional gas and coal resources,but also unconventional sources such as coal bed methane,oil shale and oil sands resources that can be explored and developed.Conventional oil and gas accumulate at Lenghu,Nanbaxian,Mahai and Yuqia area,and reservoir stratums are J1,J3,E and N.Coal resource accumulates along the area of front-zone of Qilian Mountains including Serteng,Yuqia,Hongshan,Delingha area.Minable coal seams are J1 x,J2d and J2 s.Combined with the parameters of evaluation standards of unconventional energy sources,coal bed methane accumulates at Serteng,Yuqia,Hongshan and Delingha area,and its reservoir stratum is J2.Oil shale accumulates at Yuqia,Hongshan and Delingha area,and its reservoir stratums are J1 and J2.Oil sands accumulate at Lenghu,Yuqia,Hongshan and Lulehe area,and their reservoir stratums are J and K.The north margin of Qaidam can be divided into three accumulation systems about various energy resources according to the fracture system and distribution of every kind of energy resource: Lenghu-Nanbaxian-Mahai accumulation system,Serteng-Yuqia-Hongshan accumulation system and Delingha accumulation system.The tectonic thermal evolution of Jurassic stratum is the basement of generation,distribution and combination of various energy resources in every accumulation system.According to the tectonic thermal evolution simulation analysis of four single wells,the starting time of hydrocarbon generation of Jurassic stratum in Serteng-Yuqia-Hongshan accumulation system is the earliest(150-135Ma).Delingha accumulation system takes second place(120Ma).Lenghu-Nanbaxian-Mahai accumulation system is the latest(40Ma).Combination types of energy resources of Serteng-Yuqia-Hongshan accumulation system is more than the other two systems.Generally,oil shale,conventional oil,and oil sands can transform continuous in one direction and they can influence and restrict each other on the scale.Coal,coal bed methane and conventional gas is the same.Organic material that accumulated in lakes and rivers' warm and wet environment of early-middle Jurassic is material basis of various energy resources in the north margin of Qaidam basin.Tectonic movements of late Yanshan period and late Himalayan period have the biggest impact on the accumulation and reformation of various energy resources.Lenghu-Nanbaxian-Mahai accumulation system forms the accumulation and combination model of oil sands,conventional oil and gas.Serteng-Yuqia-Hongshan accumulation system forms the accumulation and combination model of oil shale,conventional oil,oil sands,coal and coal bed methane.Delingha accumulation system forms the accumulation and combination model of coal,coal bed methane and oil shale.