塔西南坳陷山前带天然气地球化学特征和成因

发布时间：2018-04-09 08:39

  本文选题：塔西南坳陷山前带　切入点：碳氢同位素　出处：《中国矿业大学学报》2017年01期

【摘要】：阿克莫木气藏,柯克亚—柯东气藏天然气地化特征差异明显,天然气类型及气源岩一直存在争议.通过对塔西南坳陷山前带天然气稳定碳氢同位素及轻烃组成特征的分析,研究了天然气成因类型,并在此基础上,进行了气源对比,明确了气源岩类型.综合运用轻烃三角图版、稳定碳同位素图版、Mango参数、Whiticar图版及碳氢同位素图版,认为阿克莫木气藏为来自于下侏罗统的煤成气,柯克亚—柯东气藏为来自于石炭系及侏罗系混源成因的天然气.研究结果表明:阿克莫木气藏干燥系数接近1,δ~(13)C_1值为-24.2‰~-23.3‰,是塔西南坳陷山前带最重的,为来源单一的煤成气;而柯克亚—柯东气藏干燥系数均小于0.90,且存在单项性碳同位素倒转,为混源成因的湿气.前者气源岩主要为下侏罗统康苏组,干酪根以Ⅲ型为主;后者气源岩为石炭系,同时混有侏罗系气源岩,干酪根以Ⅱ-Ⅲ型为主.阿克莫木气藏苯的体积分数高达31.10%~37.38%,甲苯的体积分数为9.63%~13.46%,天然气成熟度远大于柯克亚—柯东气藏.
[Abstract]:The geochemical characteristics of natural gas in Akimomu gas reservoir and Kekeya-Kedong gas reservoir are obviously different, and the types and source rocks of natural gas have always been controversial.Based on the analysis of stable hydrocarbon isotopes and light hydrocarbon composition characteristics of natural gas in the mountain front zone of southwest depression of Tarim Basin, the genetic types of natural gas are studied. On this basis, gas source correlation is carried out, and the types of gas source rocks are defined.Using light hydrocarbon triangle plate, stable carbon isotope map plate and Mango parameter Whiticar map and hydrocarbon isotope map plate, it is considered that Akmo gas reservoir is coal-formed gas from lower Jurassic.Kekeya-Kedong gas reservoir is a natural gas from Carboniferous and Jurassic mixed origin.The results show that the drying coefficient of Akimo gas reservoir is close to 1, and the 未 ~ (13) C _ (-1) value is -24.2 鈥，

本文编号：1725681