咸水湖相烃源岩热演化过程中排出油和滞留油分子地球化学特征及其地质意义  

Molecular geochemical characteristics of expelled and retained oil during thermal evolution of source rocks in the brackish lake phase and their geological significance

作　　者：钟鸣宇 徐建永 徐耀辉[1,2] 刘岩[1,2] 李威[3] 畅厚鹏 王豫昌 李阳 ZHONG Ming-yu;XU Jian-yong;XU Yao-hui;LIU Yan;LI Wei;CHANG Hou-peng;WANG Yu-chang;LI Yang(Hubei Key Laboratory of Petroleum Geochemistry and Environment,Yangtze University,Wuhan 430100,China;Key Laboratory of Oil and Gas Resources and Exploration Technology,Ministry of Education,Yangtze University,Wuhan 430100,China;CNOOC Research Institute Co.Ltd.,Beijing 100028,China)

机构地区：[1]油气地球化学与环境湖北省重点实验室,长江大学,武汉430100 [2]油气资源与勘探技术教育部重点实验室,长江大学,武汉430100 [3]中海油研究总院有限责任公司,北京100028

出　　处：《矿物岩石地球化学通报》2025年第1期134-146,共13页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：国家自然科学基金资助项目(42272175)。

摘　　要：为了探究不同热演化阶段的咸水湖相烃源岩排出油和滞留油生物标志化合物演化规律及其指示意义,选取渤海湾盆地辽中北洼沙一段咸水湖相烃源岩样品开展多路分段式热压生排烃模拟实验。结果表明,研究区咸水湖相烃源岩在R_o为0.56%时已有少量液态烃生成,具有早期生油特点。随着热演化程度的升高,在高成熟阶段轻烃的占比明显增大。成熟度指标中的∑三环萜烷/17α-藿烷和C_(30)莫烷/C_(30)藿烷在滞留油的成熟至高熟阶段,可作为判断成熟度的可靠参数,在排出油中变化较小;沉积环境与母质来源判别指标中的C_(26)TT/C_(25)TT、C_(35)/(C_(31)-C_(35))升藿烷、(nC_(21)+nC_(22))/(nC_(28)+nC_(29))与C_(27)/C_(29)规则甾烷,在排出油中相对稳定,但在滞留油中变化较大。对比发现,排出油与滞留油的成熟度、沉积环境与母质来源参数的演化规律存在一定差异性,排出油中指示沉积环境和母质来源的生标参数的可靠性较高,而滞留油中指示成熟度的参数的可靠性较高。In order to investigate the evolution of biomarker compounds in expelled and retained oils and their indicative significance of hydrocarbon source rocks of brackish lake-phase at different thermal evolution stages,a sample of brackish lakephase hydrocarbon source rock from a section of the Liao-Zhong Bei-Wa-Sha formation in the Bohai Bay Basin was selected to carry out a simulation experiment for the hydrocarbon generation and drainage in a multiplexed and segmented thermal compression mode.The results show that a small amount of liquid hydrocarbons have been generated in hydrocarbon source rocks of brackish lake-phase when Ro is 0.56%,which is characterized by the early oil production.The proportion of light hydrocarbons in the high maturity stage increases significantly with the increase of thermal evolution.Maturity indexes(e.g.∑tricyclic terpane/17α-hopane,C_(30)-moretane/C_(30)-hopane)can be used as reliable parameters to determine the maturity of retained oil from maturity to high maturity,while they vary little for expelled oil,because expelled oil is less affected by maturity.The C_(26)TT/C_(25)TT,C_(35)/(C_(31)-C_(35))homohopane,(nC_(21)+nC_(22))/(nC_(28)+nC_(29))and C_(27)/C_(29) ratios of regular steranes,the indicators of depositional environments and parent material sources,remain stable in expelled oil but are variable in retained oil.By comparing the maturity,depositional environment and parent material source parameters of expelled oil and retained oil,it is found that there is a certain difference in the evolution pattern of the expelled oil and retained oil.The reliability of biomarker parameters indicating depositional environment and parent material source is higher in expelled oils,while the reliability of maturity parameters is higher in retained oils.

关 键 词：排出油 滞留油 分子地球化学特征 咸水湖相烃源岩 热模拟实验 

分 类 号：P593[天文地球—地球化学]