烃源岩与原油中轻馏分烃的对比——以胜利油田东营、沾化凹陷为例

Correlation of light hydrocarbons between source rock and crude oil: an example from Dongying and Zhanhua depressions in Jiyang subbasin, Bohai Bay Basin

王培荣 徐冠军 张大江 肖廷荣 任冬苓

Wang Peirong Xu Guanjun Zhang Dajiang Xiao Tingrong Ren Dongling

利用自行设计研制的密闭球磨粉碎、加热解析、氦气吹扫、冷阱捕集在线分析装置,研究烃源岩中分散有机质的轻馏分烃C—C的化学组成。对胜利油田东营、沾化凹陷10块古近系沙河街组烃源岩和其抽提物的饱和烃组分,及15个该地区的原油样品进行了C—C轻馏分色谱分析和饱和烃色-质分析,然后通过岩-油C—C轻馏分对比及油-油轻馏分对比和分类,结合岩、油中"较重"的生物标志物参数及其地质背景综合研究,认为:①E,E和E段烃源岩分散有机质中的轻馏分烃各有不同的化学组成特征;②烃源岩分散有机质C—C轻馏分的化学组成与其沉积时水体盐度之间有相关性,这种相关性与我们以前对原油的研究成果一致;③15个原油的油-岩对比说明,有8个原油的轻馏分主要源自E段烃源岩,有4个油样的轻馏分主要源自E段,另外7个似应为混源油;④自行设计的在线分析装置,可以为研究烃源岩分散有机质中C—C轻馏分的特征及其在油气地球化学方面的应用提供一个新的技术手段。

An in-house designed and manufactured on-line analyzing device consisting of vacuum ball milling,heating releasing,helium purging and liquid nitrogen trapping was used to study the light hydrocarbon fractions(C-C) of scattered organic matter in source rocks.Ten source rock samples and saturated hydrocarbon samples of their extracts as well as 15 oil samples from the Eocene Shahejie Formation in Dongying and Zhanhua depressions of Shengli oilfield were first analyzed by GC and GC-MS.Then oil-source and oil-oil correlation and classification of light hydrocarbon(C-C) were performed.The results in combination with the biomarkers and geological background were finally used to perform comprehensive study,leading to four conclusions.(a)The light hydrocarbons in the scattered organic matter of the source rocks in the upper E,lower E and E are different in chemical compositions.(b)The chemical components of C-C light hydrocarbons are related to the salinity of water column during deposition,which is consistent with that of the oils.(c)Among the 15 oil samples,8 samples contain light hydrocarbons mostly originated from the lower E source rocks,while 4 samples from the upper Es source rocks,the rest are mixed oil.(d)The on-line device provided a new way for study the characteristics of light hydrocarbons(C-C)in the scattered organic matter in source rocks and their application in petroleum geochemistry.

10.11743/ogg20130101