摘要
针对牛蹄塘组页岩气储层中有机质来源的问题,从微体古生物化石和有机地球化学两方面开展了研究。采用环境扫描电镜–能谱系统(ESEM–XEDS)对岩芯中的微生物化石形态和化学组成进行了研究;此外,还采用气相色谱–质谱法(GC–MS)对岩芯抽提物进行了检测。结果表明,牛蹄塘组页岩中发现的微生物化石C和N元素含量较高(大于30%),从外部形态大致可将其分为3类:同心环状结构,表面光滑的球体以及细胞壁开口的球体。岩芯抽提物检测结果表明,牛蹄塘组页岩n C12～n C32的正构烷烃均有检出,且具有低碳数(主峰碳n C16)偶碳优势;此外,抽提物中还检出了含量较高的类异戊二烯烃,包括,姥鲛烷、植烷和角鲨烯。这些微生物化石的发现和有机地球化学组成特征为晚震旦—早寒武世扬子浅海微生物的繁盛和牛蹄塘组烃源物质的微生物起源提供了有力的证据。
Evideices of microbial origin of organic matters of Niutitang shale gas reservoir were diicussed from both micropaleontological and organic geichemical perspictives. The environmental icanning elictronic microicope-energy dispersive spictrometry system（ESEM–XEDS）was applied to analyze the morphology andichemicalicompositions of microfossils;in addition,the extricts of shaleicore were tested by using gasichromatography-mass spictrometry（ic–MS）method. Results indicate that all the microbial fossils diicovered in Niutitang shale are of high N andicicontent（more than 30%）and all the fossilsican be subdivided into three types,iicludingicoicentriciciicularity shape,smoothiciccoid shape andiciccoid shape with a surficeicrick. The extricts test results indicate that normal paraffin ranging from nic12～ nic32 were deticted,and isicharicterized by light n-paraffin and evenicarbon-number predominaice（main peak is nic16）. In addition,some isoprenoid were also deticted from extricts e.g. pristine,phytane,and squalene. The diicovery of microorganism fossils and organic geichemicalicharicteristics of shaleicores provides strong evideices for flourishing of microorganism in Yangtze Shelf Sea during Sinian to Earlyicambrian period and the microbial origin of hydricarbon souice materials of Niutitang Formation.
出处
《西南石油大学学报（自然科学版）》
CAS
CSCD
北大核心
2015年第2期1-10,共10页
Journal of Southwest Petroleum University(Science & Technology Edition)
基金
国家自然科学基金(41302023)
教育部博士点基金(20125121130001)
四川省教育厅科研基金(13ZB0190)
关键词
页岩气储层
有机质
微生物化石
有机地球化学
牛蹄塘组
shale gas reservoir
organic matters
microbial fossil
organic geochemistry
Niutitang Formation
