南华北盆地寒武系底部马店组气源岩演化的流体包裹体分析  

Analysis of evolution of gas source rock called Madian Formation at the bottom of the Cambrian System in southern North China Basin by fluid inclusion

作　　者：孙先如[1] 贾超 李振生[2] 李建勋 曹高社[3] 

机构地区：[1]安徽省地质实验研究所,安徽合肥230001 [2]合肥工业大学资源与环境工程学院,安徽合肥230009 [3]河南理工大学资源与环境工程学院,河南焦作454000

出　　处：《天然气地球科学》2017年第11期1625-1636,共12页Natural Gas Geoscience

基　　金：国家自然科学基金(编号:41372194);中国地质调查局地质调查项目(编号:1211302108023-1)联合资助

摘　　要：寒武系底部马店组黑色岩系是南华北盆地最重要的海相烃源岩,油气显示丰富。通过分析具有油气显示岩石中流体包裹体的镜下特征、荧光特征、均一温度以及成分,总结了包裹体的类型与期次,进而反演了马店组烃源岩的油气演化历史。结果表明,马店组原生的盐水包裹体和有机包裹体均一温度范围分别为115~300℃和108~220℃,主峰温度值均为185℃;包裹体含有H2S、CO、H2、N2还原性组分,按C_(1-6)/CO_2值关系将包裹体分为CO_2型(C_(1-6)/CO_2=0.08)、高CO_2型(C_(1-6)/CO_2=0.24)、轻烃+CO_2型(C_(1-6)/CO_2=0.43~0.92)和轻烃型(CO_2≈0)。有机包裹体丰度及成分类型变化显示在成岩作用中期、成岩作用晚期和成岩期后构造期先后有3期生排烃过程,其中成岩期后构造期为高成熟生排烃高峰期,时间为早—中三叠世。马店组原生包裹体着重记录了高成熟凝析油—湿气阶段及过成熟干气阶段的油气生成和充注过程,储层的流体包裹体评价结果为工业气层或气显示层;次生包裹体可能记录了抬升剥蚀期间的流体活动过程。盆地内部中新生代沉积区的马店组烃源岩在燕山—喜马拉雅期仍有较好的二次生烃潜力,是值得进一步勘探的有利目标。The black rock series called＂Madian Formation＂,which were at the bottom of the Cambrian System in southern North China Basin,were the most important marine hydrocarbon source rocks with the best organic geochemical evaluation and hydrocarbon shows.The formation,evolution and accumulation of oil and gas in Madian Formation would be investigated by microscopic characteristics,fluorescence characteristics,homogenization temperature and composition analyses of fluid inclusion in this paper,which could provide new information for decision on further natural gas exploration in southern North China Basin.The homogenization temperatures of primary brine-aqueous inclusions and organic inclusions were 115-300℃and 108-220℃respectively with the main peak value of 185℃.The inclusions contained higher content of reductive components,such as H_2S,CO,H_2 and N_2,and were divided into CO_2 type,high CO_2 type,LH（light hydrocarbon）＋CO_2 type and LH type by C_（1-6）/CO_2 ratio.It was suggested by changes of abundance and type of organic inclusions that there are three times of hydrocarbon generation and expulsion process in the middle stage of diagenesis,late stage of diagenesis and tectonic stage after diagenesis.Therein,the tectonic stage was also peak of hydrocarbon generation and expulsion from Madian Formation,which was in early-middle Triassic with burial depth of 4 500-6 000 m.The primary inclusions of Madian Formation mainly recorded hydrocarbon generation and expulsion process during high mature as well as over mature of thermal evolution,and the reservoir was evaluated by parameters of fluid inclusions as commercial gas reservoir or gas showing reservoir,while the secondary inclusions might record the fluid activity during the uplift denudation.Madian Formation in Mesozoic and Cenozoic sedimentary basin area is still a favourable target of natural gas for further exploration,which has good secondary hydrocarbon-generating potential in Yanshan and Himalayan periods.

关 键 词：四十里长山 寒武系底部 流体包裹体 烃源岩 油气演化 

分 类 号：TE122.1[石油与天然气工程—油气勘探]