塔北地区原油正构烷烃摩尔浓度分布特征及意义

The Distributing Characteristics of Mole Concentration of n-Alkanes in Crude Oil in the Northern Tarim Basin and Its Geochemistry Meanings

塔里木盆地塔北地区海相油气的成藏过程十分复杂,并且在不同程度上经历了次生蚀变作用。因此,各种不同物性的原油正构烷烃摩尔浓度分布差异极大,基态原油相对较少。对比了塔北地区不同构造单元原油正构烷烃摩尔浓度分布类型,进而分析了原油遭受次生蚀变作用的程度。讨论了统计结果中的基态原油及其斜率因子与原油密度的关系;多段式原油正构烷烃摩尔浓度分布特征与原油密度的关系,同时,分析了蒸发分馏作用、气洗作用发生频率较高的原因及其对原油物性和化学组成的影响结果,以此解释了台盆区特殊成因类型原油(如海相高蜡油、凝析油)的成因问题。

The course of marine origin hydrocarbon accumulation in the Northern Tarim Basin was very complicated,it went through many times of secondary alterations to different extents.Therefore the distributing characteristics of the mole concentration of n-alkanes in crude oil with different physical properties were greatly different and there was relatively less attitude of the base crude oil.The distribution type of the mole concentration of n-alkanes in crude oil in different geotectonic units was compared in Tabei Area,and the extent of secondary alterations of crude oil was analyzed.Based on the above results,this paper have discussed the base crude oil in the statistics and the relation between the density of crude oil and its slope and the relation between base crude oil and the crude oil in many sections in the distributing curve of the mole concentration of n-alkanes were discussed.Meanwhile,the reasons of high evaporation fractionation and the high frequency of gas washing are analyzed the at some geotectonic units and their influence on the crude physical property and chemical components are also analyzed to explain the origin of the particular crude oil in the platform-basin region(such as the marine origin high wax content oil and condensate oil).