原油中芳烃化合物特征

CHARACTERISTICS OF AROMATIC HYDROCARBONS IN CRUDE OILS

不同沉积环境下形成的原油其芳烃组成是有差异的。一些特殊的生物标志物可反映母质输入及沉积环境。代表陆源高等植物输入的芳烃化合物有惹烯、卡达林、降松香四烯;含硫芳烃的高含量反映了咸化的还原沉积环境;苯并藿烷的形成与强烈的细菌活动有关。芳烃系列异构体的相对丰度值可作为良好的成熟度指标。

Crude oils from different basins in China,Australia and New Zealand were analyzedto characterize aromatic hydrocarbons produced in different environments by means of GC/MS.The distribution of some common compounds such as naphthalene,phenanthrene,chrysene,pyrene,fluoranthene,fluorene,dibezothiophene and dibenzofuran was found to be related tosedimentary environments.Especially the relative contents of fluorenes,dibenzofurans anddibenzothiophenes can be used to divide the oils into three types:(1)saline or marine carbonateenvironment;(2)fresh-brackish water lake;(3)swamp and coal-bearing sequence.Aromatic biomarkers(e.g.retene,nor-abietene,derivatives of lupeol and β-amyrin)repre-sent higher plant inputs with respect to the precursors of crude oils.High contents of sulphur-containing compounds like benzothiophene and dibenzothiophene series indicate a reducing andsulphur-abundant diagenetic condition.The benzohopane series(C_(32)-C_(35))was identified bothin supersaline and coal-bearing basins,and it is postulated to be the result of strong bacteriaactivity.In all the samples,a complete series of alkyl benzenes was analyzed.The similarityof its carbon-number distribution with that of n-alkanes probably suggests their genetic rela-(?)ionship.The distribution of the methylphenanthrene series reflects the ev(?)lution degree of crude oils,MPI holding positive correlation with C_(29)-sterane 20S/(20S+20R).