塔中地区不同Mango 轻烃参数原油的地球化学特征

Geochemical Characteristics of Crude Oils for Different Mango′s Light Hydrocarbon Parameters in Tazhong Region

张　敏,张　俊

Zhang Min,Zhang Jun

江汉石油学院地球化学研究中心

Geochemistry Research Center of Jianghan Petroleum Institute , Hubei 434102 ,P. R. China

塔中地区存在两种K1 值原油,塔中北斜坡正常K1 值原油和中央断垒带异常高K1值原油。研究表明不同K1 值原油中饱和烃生物标志化合物组合特征相似,但芳烃尤其是二苯并噻吩系列化合物绝对含量和内组成则差异迥然。异常高K1 值原油中二苯并噻吩系列化合物占总芳烃含量的45 %以上,其中甲基二苯并噻吩与三甲基二苯并噻吩比值大于1 ;相反,正常K1 值原油中二苯并噻吩系列化合物占总芳烃的含量低于25 % ,而甲基二苯并噻吩与三甲基二苯并噻吩比值小于1 。

Based on composition characteristics of C7 light hydrocarbons for 540 oils in Talimu Basin ,the crude oils of Tazhong region can be divided into two different K1 values [ ( 2 - methylhexane + 2 , 3 - dimethylpentane ) / ( 3 - methylhexane + 2 , 4 -dimethylpentane) ] ,i. e. normal K1 values of 0. 93～1.17 found in the northern block of Tazhong region , high K1 values of 1. 2-1. 54 in the central fault- up-lift of the field. The result s indicates geochemical features of biological markers in saturated hydrocarbon fractions for different K1 values of crude oils are similar , but the content and absolute abundance of polycyclic hydrocarbons ( PHA) , especially , dibenzothiophene series have obvious differences. The content of dibenzothiophene series to total PHA for high K1 value oils are more than 45 % , and the ratio of methyldibenzothiophene to trimethyldibenzothiophene is more than 1. In contrast, the content of dibenzothiophene series is less than 25 % , and the ratio of methyldibenzothiophene to trimethyldibenzothiophene is less than 1.