下古生界海相原油之中蜡的成因分析－－干酪根PY－GC分析提供的证据

塔里木盆地海相原油一般具有低－中含蜡的特征，油源对比表明其生油岩为下古生界寒武、奥陶系。下古生界海相干酪根主要由菌藻类无定形体组成，且具有较高的成熟度。干酪根热解气相色谱分析表明，热解产物中ｎＣ+₂₁具有较高的含量。结合原油的运移效应，从而可以建立海相原油之中含蜡的成因模式。该模式突破了较高含蜡量的原油只能来源于高等植物的传统观点，指出较高成熟度下的细菌母源是塔里木盆地海相原油含蜡的主要成因。

The Genesis of Marine Oils with Middle Wax from Lower Palaeozoic--Evidences obtaining from Kerogen's PY-GC Analysis

The marine oils derived from Cambrian-Ordovician source rocks of Lower Palaeozoic al-ways contain low-middle wax in Tarim Basin. The kerogen of bower Palaeozoic marine strata are mainly composed of amorphous matter decomposed from bacteria and algae, and are high mature, There is a higher content of C+₂₁n-alkanes in the pyrolysates by kerogen's PY-GC analysis, Associating with petroleum migration, we can conclude the genesis model of middle wax marine oils,in which the bacterium source in high maturity is a main factor, And the model breaks through the concept that the oils with higher wax are only derived from organic matters of high plants.