木里煤田聚乎更矿区天然气水合物气源探讨

发布时间：2018-06-16 11:33

  本文选题：木里煤田 + 侏罗系　； 参考：《地质学报》2017年05期

【摘要】：木里煤田位于青藏高原东北缘,近年在木里煤田聚乎更矿区中侏罗统窑街组中发现了天然气水合物。为了对天然气水合物气源类型做出客观认识,本文对木里煤田聚乎更矿区中侏罗统窑街组烃源岩样品的有机质丰度、有机质类型、有机质热演化程度进行了详细研究,并在此基础上对比了研究区天然气水合物、煤层气中烷烃气的异同,最终确定研究区天然气水合物成因类型和气源。结果表明:(1)研究区中侏罗统窑街组的泥质烃源岩有机质丰度较高,属好生油岩,有机质类型属于Ⅰ型干酪根,Ro值在0.65%～1.32%之间,有机质热演化程度达到了石油伴生气阶段;(2)天然气水合物烷烃气碳同位素特征显示大部分烷烃气呈现正碳同位素特征系列,相同碳数的天然气水合物烷烃气碳同位素较煤层气轻,天然气水合物烷烃气中甲烷含量相对煤层气较低,且天然气水合物烷烃气δ13 C2值均小于-28‰,属于油型气;(3)中侏罗统窑街组烃源岩碳同位素特征与天然气水合物的碳同位素具有高度一致性,表明研究区天然气水合物气源主要来自于中侏罗统窑街组的湖相泥岩和油页岩。
[Abstract]:The Muli coalfield is located on the northeast margin of the Qinghai-Tibet Plateau. In recent years, natural gas hydrate has been found in the middle Jurassic Yaojie formation of Juhuogan coal field in the Muli coal field. In order to make an objective understanding of the gas source types of natural gas hydrate, the abundance of organic matter, the types of organic matter and the thermal evolution of organic matter in the source rock samples of the middle Jurassic Yaojie formation in Juhugan mining area of Muli coal field are studied in detail in this paper. On this basis, the similarities and differences of alkane gas in gas hydrate and coalbed methane in the study area are compared, and the genetic types and gas sources of natural gas hydrate in the study area are determined. The results show that the muddy source rocks of the middle Jurassic Yaojie formation in the study area have high organic matter abundance and belong to the type I kerogen. The Ro value of the source rocks is between 0.65% and 1.32%. The thermal evolution of organic matter has reached the oil-associated gas stage. (2) the carbon isotopic characteristics of alkane gas in natural gas hydrate show that most of the alkane gas shows a series of normal carbon isotopic characteristics. The carbon isotope of natural gas hydrate alkane gas with the same carbon number is lighter than that of coal bed gas, the methane content of natural gas hydrate alkane gas is lower than that of coal bed gas, and the 未 13C2 value of natural gas hydrate alkane gas is less than -28 鈥，

本文编号：2026510