摘要
近年来柴达木盆地北缘(柴北缘)发现了较好的氦气资源前景,其中马北、东坪气田、团鱼山、全吉山及尖北等地区发现较高氦含量的富氦天然气(氦气含量为0.013%~1.14%,平均含量为0.33%)。综合前人研究资料系统梳理了柴北缘地区富氦天然气的组分特征、分布特征、成因特征及成藏条件,提出了柴北缘地区的氦气成藏模式。研究该地区富氦天然气的横向及纵向分布特征得出:在横向上,柴北缘地区全吉山煤田平均氦气含量最高(1.074%),其次是团鱼山煤田(0.678%),之后依次是东坪(0.28%)、马北(0.261%)、尖北(0.24%)、牛东(0.015%)气田;在纵向上,古近系路乐河组(E_(1+2))和侏罗系(J)2套层位平均氦含量最高,分别为0.61%和0.43%,能够作为主要的氦气勘探开发层系。此外,柴北缘地区天然气中的氦气主要富集在埋深3000 m以内的中浅层。根据同位素研究得到柴北缘地区氦气主要为壳源氦成因,是基底的元古宇—奥陶系花岗岩、变质岩系及铀矿等放射性矿物通过U、Th放射性衰变产生,以断裂为运移通道伴随着地下水和天然气在自生自储型和连续运移型2种成藏模式下聚集成藏,其中自生自储型运移成藏模式是氦气以游离态伴随天然气在基岩储集空间或运移至基岩顶部半风化壳中保存的过程,连续运移型成藏模式是氦气以水溶相态运移到地表形成连续供给型的氦源。
In recent years,a good prospect of helium resources has been found in the Qaidam Basin.Among them,high helium content has been found in Mabei,Dongping,Tuanyushan,Quanjishan,Jianbei and other areas on the northern margin of Qaidam Basin.The helium content in the analyzed samples is 0.013%-1.14%,and 89.36%of the helium content meets the industrial standard.Based on the analysis of the horizontal and vertical helium distribution in the northern margin of Qaidam Basin,the helium content of Quanjishan coalfield is the highest(1.074%),followed by Tuanyushan coalfield(0.678%),Dongping(0.28%),Mabe(0.261%),Jianbei(0.24%)and Niudong(0.015%)gas fields.Vertically,the average helium content of Paleogene Lulehe Formation(E_(1+2))and Jurassic(J)strata is the highest,0.61%and 0.43%,respectively,which can be used as the main helium exploration and development strata.In addition,the samples with helium content higher than 0.3%are mainly located in the shallow layer within 3000 m.According to isotope analysis,helium in the northern margin of Qaidam Basin is mainly of crust derived helium origin,which is mainly generated by radioactive minerals such as granite,metamorphic rock series and uranium ore in Proterozoic Ordovician basement through U and Th radioactive decay.The fault is used as the migration channel,and groundwater and natural gas are used as carriers.On one hand,natural gas is preserved in the semi-weathered crust at the top of the bedrock through the self-generation and self-storage migration and accumulation mode;on the other hand,the water-soluble helium in the groundwater continuously migrates to the surface through the continuous migration mode.In addition,during the continuous migration process of groundwater,part of the helium released with the change of temperature and pressure is transported to the trap along with the natural gas,and then encounters dense caprocks such as thick mudstone or gypsum rock to form a reservoir.
作者
谢菁
陈建洲
李青
安生婷
王国仓
晁海德
刘立波
XIE Jing;CHEN Jianzhou;LI Qing;AN Shengting;WANG Guocang;CHAO Haide;LIU Libo(Qinghai Fourth Geological Exploration Institute,Xining 810029,China;Qinghai Key Laboratory of Shale Gas Resources,Xining 810029,China;Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China)
出处
《天然气地球科学》
CAS
CSCD
北大核心
2023年第3期486-495,共10页
Natural Gas Geoscience
基金
中央引导地方科技发展专项资金计划“氦气地球化学特征及地下热岩元素地球化学与矿物学相关性气源追索——以共和盆地干热岩、热泉及地下热水为例”(编号:2021ZY001)资助.
关键词
柴北缘
氦气
分布
自生自储
成藏模式
Northern margin of Qaidam Basin
Helium
Distribution
Self generation and self storage
Reservoir forming mode
作者简介
谢菁(1994-),女,青海西宁人,助理工程师,主要从事能源矿产勘查及研究.E-mail:958166065@qq.com;通信作者:王国仓(1978-),男,甘肃秦安人,博士,主要从事油气地质与地球化学研究.E-mail:408535603@qq.com.
