长江三角洲启东地区全新统气源岩有机地球化学特征及生物气形成的控制因素

发布时间：2018-06-29 00:47

  本文选题：长江三角洲 + 启东　； 参考：《高校地质学报》2017年04期

【摘要】：根据钻井岩心、古生物、有机岩石学观察及有机地化测试数据分析,结合区域地质背景资料,对长江三角洲启东地区ZK01井全新统地层中两套气源岩的沉积特征、有机质丰度、有机质类型、有机质成熟度等有机地球化学特征进行了系统研究,探讨控制研究区浅层生物气生成的主要因素。结果表明,全新统河口湾—河漫滩相灰色黏土及粉砂质黏土中有机碳含量在0.20%~0.65%之间,平均0.46%,氯仿沥青"A"平均值71.71×10~(-6);浅海相深灰色淤泥质黏土有机碳含量在0.19%~0.52%之间,平均0.34%,氯仿沥青"A"平均值65.69×10~(-6);前者有机质丰度略高于后者,生气能力略强于后者。两套气源岩中有机质来源均由低等水生生物和陆源高等植物两部分组成,属于混源输入,且以陆源高等植物有机质为主,有机质类型为含草本腐殖型、含草本腐泥腐殖型。两套气源岩镜质体反射率(Ro)在0.50%~0.65%之间,正构烷烃奇偶优势明显,热解最大峰温峰多数低于435℃,表明有机质处于未成熟阶段。长江三角洲启东地区具有有利于浅层生物气生成的基础地质条件、物质条件、地球化学条件,这些因素相互作用,相互制约,相互补充。
[Abstract]:According to the data of drilling core, paleontology, organic petrology and organic geochemical testing, combined with regional geological background data, the sedimentary characteristics and abundance of organic matter of two sets of gas source rocks in the new formation of ZK01 well in Qidong area, Yangtze River Delta are studied. The organic geochemical characteristics such as the type of organic matter and the maturity of organic matter were systematically studied and the main factors controlling the formation of shallow biogas in the study area were discussed. The results show that the organic carbon content of grey clay and silty clay in the Holocene estuarine and floodplain facies is between 0.20% and 0.65%, the average is 0.46%, the average value of chloroform asphalt "A" is 71.71 脳 10 ~ (-6), and the content of organic carbon in shallow sea dark gray silt clay is 0.190.52%. The average value of chloroform asphalt "A" is 65.69 脳 10 ~ (-6), the organic matter abundance of the former is slightly higher than that of the latter, and the gas generating ability of the former is slightly stronger than that of the latter. The source of organic matter in the two sets of gas source rocks is composed of two parts of low aquatic organisms and terrestrial higher plants, which belong to mixed source input and are mainly organic matter of terrestrial higher plants. The organic matter types are herbaceous humic type and herbaceous saprophytic mud humus type. The vitrinite reflectance (Ro) of two sets of gas source rocks is between 0.50% and 0.65%, and the odd-even advantages of n-alkanes are obvious, and most of the peak temperature peaks of pyrolysis are lower than 435 鈩，

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