【摘要】 <正> 本文利用柴达木盆地18个原油样品的气相色谱分析成果,对该盆地原油烷烃的地球化学特征进行了初步研究. 一、地质概况 柴达木盆地为印支运动后形成的沉积盆地.侏罗纪时,由于盆地边缘断裂活动,基岩解体,形成了一系列互相分割、面积不大的断陷.盆地北部沉积的中、下侏罗统含煤建造为暗色泥质岩夹炭质泥岩及煤线,厚度100—500米.冷湖三号和鱼卡油田证实侏罗系的一些层位（J₂⁶—J₂⁷）具有一定的生油能力.渐新世至第三纪晚期,沉积了巨厚的暗色泥质岩。在茫崖坳陷,钻探证实,它是一套浅湖—深更多还原

【Abstract】 Crude oils of different ages （J₂,E₃-N₂¹,and N₂²）from Qaidam basin canbe divided into three types according to the patterns of distribution of hydro-carbons 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 phytaneratio is 2.44--2.90.Crude oils E₃-N₂¹ are characterized by higher Phytane peakthan 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 adominant role on chromatogram of normal paraffins.For crude oil N₂²,thelight components take a prevailing place.The main peak carbon of normal paraf-fins is C₁₃,while the pristane/phytane ratio is 1.26.In N₁ and N₂¹,thereare some crude oils formed by degradation,in which the action of microbes isof prime importance.Neady all normal paraffins are degraded by microbes,therefore,the isoprenoids are the foremost on the whole hydrocarbon chroma-togram.Questions of migration of crude oils are also tentatively discussed here.更多还原