摘要
依据珠江口盆地惠州凹陷不同类型原油样品中各类生物标志物分布与组成特征的分析结果,可以将其划分为煤成油和湖相油两大类。以HZ9-2-1井为代表的煤成油表现出强烈的姥鲛烷优势,C19~C_26三环萜烷系列相对丰度呈现阶梯状依次降低,C_24四环萜烷相对丰度远高于C_26三环萜烷,藿烷系列C_29降藿烷和C31升藿烷较为丰富,新藿烷（Ts和C_29Ts）含量很低,甾烷组成中C_29规则甾烷和重排甾烷占绝对优势,这与典型煤成油的分子地球化学特征一致。湖相油中姥鲛烷优势较弱,C_19~C_26三环萜烷系列呈现以C_21为主峰的正态分布,C_24四环萜烷丰度与C_26三环萜烷丰度相当,新藿烷和重排藿烷含量中等,伽马蜡烷含量极低,2-甲基藿烷与C_304-甲基甾烷十分丰富且存在正相关关系。它们可以作为鉴别研究区原油成因类型的主要依据。
Based on the distributions and compositions of various biomarkers from different crude oils in Huizhou sag of Pearl River Mouth Basin,they can be classified into coal-derived and lacustrine oil.The coal-derived oils from well HZ9-2-1have the characteristics of higher Pr/Ph value（more than 4.5）,abnormally abundant C_24 tetracyclic terpane,step-like decreasing pattern for C19-C_26 tricyclic terpanes, more abundant C_29 norhopane and C_31 homohopane,lower neohopanes in C_27-C_（35） hopanes,and absolutely predominant C_29 rearranged and regular steranes in C_27-C_29 steranes.These features are the main indicators to discriminate coal-derived oils from other oils.However,for lacustrine oils,their Pr/Ph values are relatively low（less than 3.0）,the abundances of C_24 tetracyclic terpane and C_26 tricyclic terpane are similar,the distribution of C_19-C_26 tricyclic terpanes is normal with the main peak of C_21,neohopanes and rearranged hopanes are moderate,gammacerane index indicating paleosalinity is very low.It is noted that 2-methylhopanes and 4-methylsteranes indicating cyanobacteria and dinoflagellate input are very abundant respectively,and the variation of their relative abundances has a normal correlation,representing a specific ecosystem condition to be suitable for the growth of two kinds of microbes.They have an important role in oil-source correlation.
出处
《地球科学与环境学报》
CAS
2016年第2期235-244,共10页
Journal of Earth Sciences and Environment
基金
国家自然科学基金项目(41272169)
国家科技重大专项项目(2008ZX05025-003-001)
关键词
有机地球化学
原油
生物标志物
链烷烃
萜烷
甾烷
惠州凹陷
珠江口盆地
organic geochemistry
crude oil
biomarker
chain alkane
terpane
sterane
Huizhou sag
Pearl River Mouth Basin
