柳河盆地鹰嘴砬子组烃源岩地球化学特征及意义

Geochemical Characteristics and Significance of Source Rocks in Yingzilazi Formation of Liuhe Basin

随着吉林油田外围盆地勘探进程,逐步发现柳河盆地有很大勘探潜力。为了探究柳河盆地主力生油层位,研究以柳地1井、柳地2井岩心为对象进行了岩石热解、TOC分析、干酪根镜检、饱和烃气相色谱和饱和烃色谱—质谱分析等实验,评价了鹰嘴砬子组烃源岩生烃潜力。结果表明:鹰嘴砬子组烃源岩有机质丰度中等,类型为Ⅰ-Ⅱ型干酪根,成熟度处于成熟—过成熟阶段;饱和烃正构烷烃以低碳数为主,规则甾烷C27-C28-C29整体呈现“L”型分布,母质来源主要为水生生物贡献,夹杂少量陆源高等植物贡献;Ts/Tm、姥鲛烷植烷比值反映沉积环境主要为弱还原环境。综合评价鹰嘴砬子组烃源岩有良好的生油气潜力,可能为柳河盆地主力生油层位,有一定勘探价值。

With the exploration process of peripheral basins of Jilin Oilfield,great potential exploration has been gradually found in Liuhe Basin.This study focuses on exploring the main oil generation horizon in Liuhe Basin.Here,No.1 well and No.2 well were collected and analyzed for samples.The organic geochemical tests and analysis methods are concluded in rock phrolysis,and TOC analysis.Kerogen microscopic examination and GC-MS were used to evaluate the hydrocarbon-generating potentials of the source rocks of Yingzuilazi formation.The results show that the organic matter is mainly of TypeⅠandⅡ1 in a maturate stage,with great hydrocarbon-generating potential,which is determined to be relatively good source rocks.The source rocks of Yingzuilazi formation have higher amounts of low-molecular weight normal alkanes.Sterane mass chromatograms are characterized by a predominance of C27 relative to C28 and C29 steranes which suggests aquatic organic matter have a dominant contribution.Ts/Tm and Pr/Ph ratios of source rock samples indicate that depositon environment is in weak reduction environment.The comprehensive evaluation shows that the source rocks of Yingzuilazi formation have good hydrocarbon generation potential which may be the main source reservoir in Liuhe basin,valued to be explored.