米泉低阶煤煤层气中CO_(2)异常赋存特征与成因  

Abnormal Occurrence Characteristics and Genesis of CO_(2) in Middle and Low Rank Coalbed Methane in Miquan Mining Area

作　　者：张娜 伏海蛟 刘玲[3] 杨曙光 王刚 李跃国 王佳伟 杨昊宇 Zhang Na;Fu Haijiao;Liu Ling;Yang Shuguang;Wang Gang;Li Yueguo;Wang Jiawei;Yang Haoyu(Coalbed Methane Research and Development Center of Xinjiang Coal Geological Exploration Bureau,Urumqi,Xinjiang,830091,China;School of Resources,China University of Geosciences,Wuhan,Hubei,430074,China;Petroleum Exploration and Production Research Institute,SINOPEC,Beijing,100083,China)

机构地区：[1]新疆维吾尔自治区煤田地质局煤层气研究开发中心,新疆乌鲁木齐830091 [2]中国地质大学(武汉)资源学院,湖北武汉430074 [3]中国石化石油勘探开发研究院,北京100083

出　　处：《新疆地质》2023年第2期240-245,共6页Xinjiang Geology

基　　金：新疆维吾尔自治区自然科学基金资助项目(2020D01A97);国家自然科学基金青年基金资助项目(41902173);国家自然科学基金面上基金资助项目(4217020846)共同资助。

摘　　要：对米泉矿区以往煤层气勘查成果统计发现,气体含量中CO_(2)浓度异常高,部分气样浓度甚至超过40%。通过系统开展气体组分、CH4与CO_(2)碳同位素、稀有气体同位素等地化分析,发现该区CO_(2)浓度随埋深增大呈增高趋势。当埋深大于800 m时,CO_(2)浓度超过40%;CO_(2)具明显壳源成因特征,无幔源CO_(2)的混入。说明该区煤层气主要为CO_(2)还原途径形成的次生生物气体,少量样品具热成因气特征;CO_(2)异常富集可能是3个方面因素耦合作用的结果,即处于微生物产甲烷活动早期阶段、CO_(2)还原途径产甲烷活动受到抑制及滞留的水体环境。According to the statistics of previous coalbed methane exploration results in Miquan mining area,we found that the CO_(2) concentration in the gas content is abnormally high,and the CO_(2) concentration of some gas samples even ex-ceeds 40%.But there are few studies about of regularity and genetic mechanism of anomalous occurrence of CO_(2) in CBM in this area.Based on this,this study systematically carried out geochemical analysis of gas composition,CH4 and CO_(2) carbon isotopes,noble gas isotopes,etc.We found that the CO_(2) concentration in this area shows an increasing trend with the increase of burial depth,and when the burial depth is more than 800 m,the abnormal phenomenon of CO_(2) con-centration over 40%appears in large numbers;CO_(2) has obvious characteristics of crust origin,without the mixing of mantle source CO_(2).It shows that the coalbed methane in this area is mainly secondary biogenic gas formed by CO_(2) reduc-tion,and a few samples show the characteristics of thermogenic gas.The abnormal enrichment of CO_(2) may be the result of the coupling of three factors:the early stage of microbial methanogenesis、the inhibition of methanogenesis by CO_(2) reduction pathway,and the stagnant water environment.

关 键 词：米泉矿区 煤层气 稀有气体 CO_(2)成因 异常富集 

分 类 号：U473.22[机械工程—车辆工程]