天然气地球化学特征及成因分析——以鄂尔多斯盆地东胜气田为例

发布时间：2018-03-14 20:47

本文选题：天然气　切入点：地球化学特征　出处：《中国矿业大学学报》2017年01期 　论文类型：期刊论文

【摘要】：阐明鄂尔多斯盆地东胜气田天然气地球化学特征并厘清其天然气成因及来源.基于该气田的6口井及前人已经发表的其它主要气田25口井天然气组分、碳等同位素特征,轻烃组分特征及实际地质背景,对该气田天然气地球化学特征及来源进行了较详细分析,认为东胜气田天然气具有与上古生界其它气田相似的成因,为典型的煤成气;该气田天然气组分、同位素及轻烃特征与其南部苏里格气区存在明显差异,该气田天然气主要来自于其下伏煤系并非来自于南部烃源岩.研究结果表明:东胜气田天然气以烷烃气为主,表现为干气,天然气中甲烷体积分数为93.69%~93.96%,乙烷体积分数为3.57%~3.71%,丙烷体积分数为0.85%~0.92%,丁烷体积分数为0.21%~0.37%;含少量非烃气体CO_2和N_2;烷烃气碳同位素具有正碳同位素系列,表现为原生特点;C_7轻烃化合物表现为甲基环己烷优势,庚烷值及异庚烷值分布区间分别为14.3%~16.0%和1.9%~2.6%,结合碳同位素认为该气田为烃源岩成熟-高成熟过渡带阶段形成的天然气;天然气K_1值[K_1=(2-甲基己烷+2,3-二甲基戊烷)/(3-甲基己烷+2,4-二甲基戊烷)]为1.2.
[Abstract]:The geochemical characteristics of natural gas in Dongsheng gas field in Ordos Basin are expounded and the origin and source of natural gas are clarified. Based on the isotopic characteristics of natural gas components and carbon etc. in 6 wells of this gas field and 25 other major gas fields published by predecessors, The geochemical characteristics and source of natural gas in Dongsheng gas field are analyzed in detail. It is considered that the gas in Dongsheng gas field is of similar origin to other gas fields in Upper Paleozoic and is a typical coal-formed gas. The composition, isotopic and light hydrocarbon characteristics of natural gas in this gas field are obviously different from those in Sulige gas area in the south of the gas field. The natural gas of this gas field mainly comes from its underlying coal measures and not from the southern source rock. The results show that the natural gas in Dongsheng gas field is mainly alkane gas, which is characterized by dry gas. The volume fraction of methane in natural gas is 93.699.96, the volume fraction of ethane is 3.570.71, the volume fraction of propane is 0.850.92, the volume fraction of butane is 0.210.37. there are small amounts of non-hydrocarbon gases CO_2 and N2s, and alkane gas carbon isotopes have a series of normal carbon isotopes. The primary characteristics of the light hydrocarbon compounds are that the heterosis of methylcyclohexane is present in the light hydrocarbon compounds, the distribution ranges of heptane value and isoheptane value are 14.3U 16.0% and 1.9g / 2.6g respectively. The gas field is considered to be natural gas formed in the mature-high mature transitional zone of the source rock combined with carbon isotopes. The K1 value of natural gas is 1.2.
【作者单位】：中国石油勘探开发研究院;中国科学院地质与地球物理研究所;中海油研究总院;湖北省地质局第三地质大队;
【基金】：中国石油天然气股份有限公司科技项目(2014B-0608) 国家重点基础研究计划(973)项目(2006CB202308,2011CB201100) 国家重大科技专项(2016ZX05007-001) “十二五”国家重大专项(2011ZX05007-004)
【分类号】：P618.13

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