富氦天然气藏氦源岩特征及关键评价参数  

Characteristics and key evaluation parameters of helium source rocks in helium-rich natural gas reservoirs

作　　者：尤兵 陈践发[1,2] 肖洪 刘晓强 刘凯旋 YOU Bing;CHEN Jianfa;XIAO Hong;LIU Xiaoqiang;LIU Kaixuan(State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum(Beijing),Beijing 102249,China;College of Geosciences,China University of Petroleum(Beijing),Beijing 102249,China;College of Chemistry and Environmental Engineering,Sichuan University of Science and Engineering,Zigong,Sichuan 643000,China)

机构地区：[1]“油气资源与探测”国家重点实验室·中国石油大学(北京) [2]中国石油大学(北京)地球科学学院 [3]四川轻化工大学化学与环境工程学院

出　　处：《天然气工业》2022年第11期141-154,共14页Natural Gas Industry

基　　金：国家重点研发计划项目“富氦天然气成藏机制及氦气资源分布预测技术”(编号:2021YFA071900)。

摘　　要：对氦气成因与来源的研究是氦气资源勘探中的关键和核心内容之一,其不仅可以为氦气成藏机制的建立提供理论基础和支撑,也可为富氦天然气藏预测提供关键证据和认识。为此,基于前人研究成果,系统梳理了富氦天然气藏中氦源研究现状与研究方法,总结了壳源氦源岩的特征和关键评价参数。研究结果表明:①天然气藏中氦气的3个主要来源为大气源、壳源和幔源,现有研究富氦天然气藏中的氦多数以壳源氦贡献为主;②壳源氦的氦源岩从根本上决定了气藏中氦气含量,其通常为富含铀、钍放射性元素的古老岩石,如地壳中花岗岩、富有机质页岩、变质岩等,其中古老的基底花岗岩是全球大部分富氦天然气藏的主要氦源岩;③富有机质页岩由于生烃能力较生氦能力强,天然气作为运载气的同时也将生成的氦气稀释到工业品味以下,难以独立作为富氦天然气藏的氦源岩。结论认为,目前对有关氦源岩的研究还不够系统和深入,为了建立氦源岩评价体系,提出了4个氦源岩关键评价参数,分别为氦源岩石类型、氦源岩铀、钍元素丰度、氦源岩形成年龄及氦源岩体积规模,以期为氦源相关理论研究奠定基础。The study on helium genesis and source is one of the core contents in helium resource exploration,and it can not only provide a theoretical basis and support for the establishment of helium accumulation mechanism,but also key proof and understanding for the prediction of helium-rich natural gas reservoir.Based on previous research results,this paper systematically analyzes the research status and methods of helium sources of helium-rich natural gas reservoirs and summarizes the characteristics and key evaluation parameters of crust-derived helium source rocks.And the following research results are obtained.First,atmosphere,crust and mantle-derived helium are the three main sources of helium in natural gas reservoirs,and the helium in the studied helium-rich natural gas reservoirs is mostly contributed by crust-derived helium.Second,the source rocks of crust-derived helium fundamentally control the helium content of gas reservoir and usually refer to ancient rocks that are rich in radioactive elements of uranium and thorium,such as granites,organicrich shales,and metamorphic rocks.Among which,the ancient basement granites are the main helium source rocks of most heliumrich natural gas reservoirs all over the world.Third,organic-rich shales have stronger hydrocarbon-generating capacity than heliumgenerating capacity.Acting as carrier gas,natural gas dilutes the generated helium below the industrial grade,and thus organic-rich shales are difficult to independently serve as helium source rocks for helium-rich natural gas reservoirs.In conclusion,the research on helium source rocks is not systematic and complete enough,and four key evaluation parameters of helium source rock are proposed for establishing a helium source rock evaluation system,including rock type,uranium and thorium abundance,formation age and volume scale of helium source rock,so as to lay a foundation for the research of helium source related theories.

关 键 词：氦气 壳源氦 氦源岩 富氦天然气藏 基底花岗岩 富有机质页岩 铀、钍元素丰度 评价参数 

分 类 号：P618.13[天文地球—矿床学]