烃源岩中无机矿物对有机质生烃的影响

发布时间：2018-02-02 14:14

本文关键词： 有水热解氢同位素碳正离子机理无机矿物烃源岩　出处：《石油实验地质》2017年02期 　论文类型：期刊论文

【摘要】：对华北下花园地区下马岭组及鄂尔多斯盆地延长组2组低成熟泥岩全岩及分离的干酪根样品开展有水热解实验,探讨了烃源岩源内无机矿物对有机质生烃及同位素分馏的影响。实验结果表明,两组全岩有水体系液态烃及气态烃产率不同程度低于干酪根有水体系,CO_2及H2产率则明显偏高。同时,全岩有水热解体系气体产物异构烃含量相对较低,表明烃源岩中无机矿物的加入抑制了水—有机质的反应并一定程度上改变了反应途径。稳定同位素的分析结果表明,相同热演化程度下,2组全岩及相应干酪根热解生成的甲烷碳同位素变化不大,但前者生成的二氧化碳碳同位素显著升高,且气态烃氢同位素更低。表明全岩有水热解体系下,烃源岩中的无机矿物参与到有机质热解过程中,改变了CO_2产率及同位素组成,并存在H_2间接加氢作用。
[Abstract]:The hydrothermal decomposition experiments were carried out on the whole rock and separated kerogen samples of the low mature mudstone in the Lower Maling formation and the Yanchang formation of the Ordos Basin in the Xiayuayuan area of North China. The effects of inorganic minerals in source rocks on hydrocarbon generation and isotopic fractionation of organic matter are discussed. The experimental results show that the yields of liquid hydrocarbon and gaseous hydrocarbon in two groups of water-bearing systems are lower than those in kerogen systems. The yields of CO_2 and H _ 2 are obviously higher. Meanwhile, the content of iso-hydrocarbon in the gas products of the whole rock with hydrothermal decomposition system is relatively low. The results show that the addition of inorganic minerals in the source rocks inhibits the water-organic matter reaction and changes the reaction path to some extent. The carbon isotopes of methane produced by pyrolysis of whole rock and corresponding kerogen in the two groups have little change, but the carbon isotope of carbon dioxide generated by the former is significantly increased, and the hydrogen isotope of gaseous hydrocarbon is lower, which indicates that the whole rock has hydropyrolysis system. The inorganic minerals in the source rocks participate in the pyrolysis of organic matter, change the CO_2 yield and isotopic composition, and have the H _ S _ 2 indirect hydrogenation.
【作者单位】：北京大学地球科学与空间科学学院;中国石油勘探开发研究院;中国石油天然气股份有限公司油气地球化学重点实验室;
【基金】：国家油气专项(2016ZX05007001) 中国石油天然气股份有限公司项目(2014D-3209)资助
【分类号】：P618.13
【正文快照】： 烃源岩主要由无机矿物与有机质两部分构成,两个地质体间不可分割。传统地球化学理论认为干酪根作为油气生成的母质,是烃源岩中有机质的主体,对于油气形成和演化过程中有机质与无机质之间的相互作用则关注程度较低[1-2]。近几十年来,大量的勘探实践与研究分析则显示,在有机质演

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