焦石坝五峰组-龙马溪组页岩硅质生物成因的证据及其地质意义

发布时间：2018-02-06 07:55

本文关键词： 焦石坝五峰组-龙马溪组页岩硅质生物成因地质意义　出处：《中国石油大学学报(自然科学版)》2017年01期 　论文类型：期刊论文

【摘要】：以页岩露头样品和钻井岩屑样品元素测量结果为依据,结合岩心和薄片观察,分析焦石坝五峰组-龙马溪组页岩的硅质生物成因的证据,并探讨其地质意义。结果表明:焦石坝五峰组—龙马溪组页岩中存在大量的笔石、角石、珊瑚等古生物化石和放射虫微体生物化石;SiO_2含量介于40%~80%,平均达63%;过量硅含量为2.6%~55.31%,其中五峰组和龙马溪组页岩下段过量硅含量较高,平均分别为41.3%和25.5%;Al/(Al+Fe+Mn)值介于0.62~0.87,与纯生物成因硅质岩相近,Al-Fe-Mn三角图上,研究区页岩样品绝大部分落在生物成因区,表明页岩硅质成分属于生物成因;深水陆棚贫氧、缺氧沉积环境有利于页岩有机质的富集和有机孔隙的发育,对于页岩天然裂缝的形成和后期人工压裂都具有重要意义。
[Abstract]:Based on the element measurement results of shale outcrop and drilling cuttings, combined with core and thin slice observation, the evidence of siliceous biogenesis of Jiaoshiba Wufeng formation and Longmaxi formation is analyzed. The results show that the shale of Jiaoshiba Wufeng formation and Longmaxi formation contains a lot of fossils such as graptolite, hornstone, coral and radiolarian microfossils. The content of SiO_2 was between 40 and 80, with an average of 63. The excess silicon content is 2.6X 55.31, of which the excess silicon content in the lower shale of Wufeng formation and Longmaxi formation is higher, with an average of 41.3% and 25.5, respectively. The value of Al/(Al Fe mn is between 0.62 and 0.87, which is close to that of pure biogenic siliceous rocks on the Al-Fe-Mn triangulation diagram. Most of the shale samples in the study area fall in the biogenic area. The results show that the siliceous composition of shale belongs to biological origin. The oxygen-poor environment in deep water shelf and anoxic sedimentary environment are conducive to the enrichment of organic matter and the development of organic pores. It is of great significance for the formation of natural fractures and artificial fracturing of shale.
【作者单位】：页岩油气富集机理与有效开发国家重点实验室;中石化石油工程技术研究院;
【基金】：中国石化重点科技攻关项目(P13012)
【分类号】：P618.13

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