渤海湾盆地冀中坳陷上古生界煤系烃源岩地球化学特征与生烃演化  

Geochemical characteristics and hydrocarbon generation evolution of Upper Paleozoic coal measures in Jizhong Depression,Bohai Bay Basin

作　　者：郭萍 GUO Ping(College of Engineering Technology,College of Resource Exploration and Engineering,Yangtze University,Jingzhou 434020,China)

机构地区：[1]长江大学工程技术学院资源勘查工程学院,湖北荆州434020

出　　处：《天然气地球科学》2020年第9期1306-1315,共10页Natural Gas Geoscience

基　　金：中国石油华北油田分公司校企合作项目(编号:HBYT-YJY-2017-JS-01);长江大学工程技术学院院级科研基金项目(编号:2019KY04)资助。

摘　　要：为深化渤海湾盆地冀中坳陷上古生界煤系烃源岩地质认识,以有机地球化学实验作为研究手段,分析了上古生界煤系烃源岩有机地球化学特征及其生烃能力,利用埋藏史—热史分析,探讨了生烃演化过程。研究结果显示,霸县凹陷的文安地区、武清凹陷和大城凸起上古生界烃源岩有机质丰度最高,其次是廊固凹陷北部地区,深县凹陷、束鹿凹陷相对较低;冀中坳陷东北部上古生界煤层显微组分以文安地区壳质组含量为最高,平均达29.1%,壳质组含量大于20%的样品数占样品总数的80%以上;生烃热演化经历了低成熟阶段、二次成熟阶段、高成熟凝析油湿气阶段和过成熟干气阶段;在白垩纪末,煤系烃源岩埋藏深度约为1200~2000 m,RO值为0.5%~0.7%,达到一次生烃状态;在古近纪末,煤系烃源岩最大埋深>7000 m,超过中生界最大古埋藏深度或古温度,开始二次生烃,资源潜力较好。In order to deepen the geological understanding of the source rocks of the Upper Paleozoic coal measures in Jizhong Depression of Bohai Bay Basin,the organic geochemical experiment is used as the research method to analyze the geological characteristics of the source rocks of the Upper Paleozoic coal measures in Jizhong Depression,evaluate the hydrocarbon generating capacity,and discuss the hydrocarbon generating evolution process by using the burial history-thermal history analysis and regional geological background.The results show that the organic carbon abundance of Upper Paleozoic source rocks in Suqiao Wen'an area,Wuqing Depression and Dacheng Uplift of Baxian Depression is the highest,followed by Hexiwu structural belt in Langgu Depression,and Shenxian and Shulu depressions are relatively low;the content of Upper Paleozoic coal macerals in the northeast of Jizhong Depression is the highest in Suqiao area,with an average of 29.1%,and the content of crust is more than 20%.The number of samples accounts for more than 80%of the total number of samples;the thermal evolution of hydrocarbon generation has experienced low maturity stage,secondary maturity stage,high maturity condensate wet gas stage and over mature dry gas stage;the burial depth of source rock of coal measures at the end of Cretaceous was about 1200-2000 m,and RO was 0.5%-0.7%,reaching the evolution state of primary hydrocarbon generation stage;the maximum burial depth of source rock of coal measures in Paleogene was more than 7000 m,exceeding the maximum burial depth or paleotemperature in Mesozoic,the secondary hydrocarbon generation begins,and it has superior resource potential.

关 键 词：煤系烃源岩 古生界 地球化学特征 生烃演化 冀中坳陷 

分 类 号：TE122.113[石油与天然气工程—油气勘探]