摘要
氦气由于其独特的物理化学性质及稀缺性被列为重要的战略资源。目前中国氦气资源需求缺口巨大,对外依存度极高,急需加强氦气资源的勘探及研究工作。以黔南坳陷震旦系陡山沱组和寒武系牛蹄塘组页岩(气)为研究对象,基于气体组分及碳同位素、稀有气体组成及同位素比值、页岩的主、微量元素分析等测试结果,对页岩气中氦气成因及来源进行研究。结果表明:陡山沱组和牛蹄塘组页岩气主要以N_(2)为主,CH_(4)含量次之,He含量介于(1 533.1~2 323.7)×10^(-6)之间,^(3)He/^(4)He值为0.009~0.010 Ra(Ra=1.4×10^(-6)),显示以壳源氦为主。页岩气样品中^(21)Ne/^(22)Ne值和^(40)Ar/^(36)Ar值高于相应的空气值,表明存在不同比例壳源^(21)Ne和^(40)Ar加入。研究气体样品中壳源放射性成因^(4)He/^(40)Ar的实测值与地壳放射性成因^(4)He/^(40)Ar值接近,而远小于岩石原位放射性成因^(4)He/^(40)Ar的理论计算值,表明可能存在地壳或岩石解析过程中空气来源的稀有气体稀释了岩石原位放射性成因的^(4)He和^(40)Ar。基于页岩层段原位氦气生成速率与地壳氦释放通量的理论计算,页岩气样品中^(4)He的原位累积时间和地壳补给时间都远小于对应地层的沉积年龄,表明地层沉积过程中存在构造运动导致原位生成的氦气发生散失。
Helium is listed as an important strategic resource due to its unique physical and chemical properties and scarcity.At present,China's helium resources are in great demand and highly dependent on foreign countries.It is urgent to strengthen the exploration and research of helium resources.This paper takes the shale(gas)of the Sinian Doushantuo Formation and the Cambrian Niutitang Formation in the Qiannan Depression as the research object,and studies the origin and source of helium in shale gas by means of gas composition and carbon isotope,noble gas composition and isotope ratio,major and trace element analysis of shale.The results show that the shale gas in Doushantuo Formation and Niutitang Formation is dominated by N_(2),followed by CH_(4),with He content ranging from 1533.1×10^(-6) to 2323.7×10^(-6),and ^(3)He/^(4)He ratio ranging from 0.009 Ra to 0.010 Ra(Ra=1.4×10^(-6)),indicating that crustal source helium is the main source.The ratios of ^(21)Ne/^(22)Ne and ^(40)Ar/^(36)Ar in shale gas samples are higher than the corresponding air values,indicating that there are different proportions of ^(21)Ne and ^(40)Ar added from crust sources.The measured value of crust derived radiogenic ^(4)He/^(40)Ar in the studied gas sample is close to the value of crust derived radiogenic ^(4)He/^(40)Ar(3.09-6.00),but far less than the theoretical calculated value of rock derived in-situ radiogenic ^(4)He/^(40)Ar,which indicates that there may be rare gases from the upper crust or air during the rock resolving that dilute the ^(4)He and ^(40)Ar of rock derived in-situ radiogenic.Based on the theoretical calculation of in-situ helium generation rate and crustal helium release flux in shale intervals,the in-situ accumulation time and crustal recharge time of ^(4)He in shale gas samples are far less than the sedimentary age of corresponding strata,indicating that tectonic movement caused the in-situ helium loss in the process of formation deposition.
作者
蒙炳坤
李靖
周世新
淡永
张庆玉
聂国权
MENG Bingkun;LI Jing;ZHOU Shixin;DAN Yong;ZHANG Qingyu;NIE Guoquan(Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences/Key Laboratory of Petroleum Resources Research,Gansu Province,Lanzhou 730000,China;School of Petroleum and Environmental Engineering,Yanan University,Yan’an 716000,China;Institute of Karst Geology,CAGS,Guilin 541004,China;Chengdu Centre,China Geological Survey,Chengdu 610081,China)
出处
《天然气地球科学》
CAS
CSCD
北大核心
2023年第4期647-655,共9页
Natural Gas Geoscience
基金
中国科学院稳定支持青年团队计划(编号:YSBR-017)
中国地质调查项目(编号:DD20190722,DD20190723,DD20221658)
中国地质科学院岩溶地质研究所基本科研业务费项目(编号:2022003)联合资助.
关键词
页岩气
氦气成因
氦氩来源预测
累计年龄
Shale gas
Helium origin
Prediction of helium and argon sources
Cumulative age
作者简介
蒙炳坤(1992-),男,陕西永寿人,博士,讲师,主要从事油气地球化学研究.E-mail:bingkunmeng@126.com;通信作者:李靖(1986-),男,山东泰安人,博士,副研究员,主要从事非常规油气地质与地球化学、氦气成藏地质学研究.E-mail:lj1926@lzb.ac.cn.
