Abstract:

Crude oils of different ages (J₂,E₃-N₂¹,and N₂²)from Qaidam basin can be divided into three types according to the patterns of distribution of hydrocarbons on chromatogram.Among them.the maturity of crude oil J₂ is higher.The main peak carbon of normal pararffins is C₁₅,and the pristane to phytane ratio is 2.44—2.90.Crude oils E₃-N₂¹ are characterized by higher Phytane peak than other.The pristane/phytane ratio 0.86—0.52,and the main peak carbonof normal paraffins commonly is C₂₂.It is obvious that even carbons play a dominant role on chromatogram of normal paraffins.For crude oil N₂²,the light components take a prevailing place.The main peak carbon of normal paraffins is C₁₃,while the pristane/phytane ratio is 1.26.In N₁ and N₂¹,there are some crude oils formed by degradation,in which the action of microbes is of prime importance.Neady all normal paraffins are degraded by microbes,therefore,the isoprenoids are the foremost on the whole hydrocarbon chromatogram.Questions of migration of crude oils are also tentatively discussed here.