鄂尔多斯盆地东缘煤系富氦资源的发现及其资源潜力与勘探开发对策

Discovery of Helium-Rich Resources in Coal Seams of the Eastern Margin of Ordos Basin and Its Resource Potential as well as Exploration&Development Strategies

中国氦气利用对外依存度高,资源安全问题突出,寻找氦气资源、明确氦气富集机理、寻找勘探开发对策是目前面临的紧迫任务。鄂尔多斯盆地煤系气资源十分丰富,目前的勘探开发成效显著。为查明鄂尔多斯盆地煤系氦气资源潜力及分布,在对鄂尔多斯盆地东缘(简称鄂东缘)煤系气系统取样检测的基础上,对鄂尔多斯盆地煤系氦气资源分布展开了研究。结果表明:鄂东缘三交北地区煤系气整体可以达到富氦天然气的标准,按2020年底的探明储量折算氦气探明储量约4000×10^(4) m^(3),因此,鄂尔多斯盆地煤系地层中或存在氦气富集区。大宁—吉县地区按2021年提交的深层煤层气探明地质储量1121.62×10^(8) m^(3)测算,折算深层煤层氦气探明储量约3400×10^(4) m^(3),因此,鄂尔多斯盆地具备建设煤系氦气战略储备基地的基础,建议加快三交北区块煤系氦气的分离开发,避免氦气资源的浪费。氦同位素比值揭示鄂东缘煤系氦气以壳源成因为主,三交北地区煤系地层具备良好的氦气富集条件,是煤系氦气资源勘查的重点地区,在开展煤系氦气资源普查的同时,应加强对煤系氦气资源勘查技术与富集规律研究,为有效利用煤系氦气提供技术支撑,以保障国家的氦气资源安全。

Helium has an irreplaceable role in the development of various high-tech industries.Currently,the helium used in China mainly comes from imports,with a high degree of dependence on foreign countries,and the security of helium resources is a prominent issue.It is an urgent task to search for helium resources,clarify the enrichment mechanism of helium,and find out the countermeasures of exploration and development.The Ordos Basin is rich in coalbed methane resources,and the current exploration and development achievements are remarkable.In order to clarify the distribution and potential of helium resources in the Ordos Basin,this paper,on the basis of systematic sampling and analysis of the eastern margin of the Ordos Basin,has carried out a study on the distribution of helium resources in coal bed in the Ordos Basin.The results show that,the coalbed methane of Sanjiaobei area at the eastern edge of the basin as a whole can reach the helium-rich natural gas standard.Based on the proved reserves submitted by the end of 2020,the converted helium proved reserves are about 40 million cubic meters.Therefore,helium-rich areas may also exist in the coal beds of the Ordos Basin.The converted helium proven reserves are about 34 million cubic meters based on the proven geological reserves of 1121.62×10^(8) m^(3) of deep coalbed methane submitted by the Daning-Jixian area in 2021.the Ordos Basin has the capability to build coalbed(rock)-helium strategic reserve base and it is recommended to accelerate the separation and development of coalbed helium in Sanjiao block to avoid the waste of helium resources.Meanwhile,the helium isotope ratio reveals that helium in the coal bed of Ordos Basin is mainly of crustal origin,and Sanjiaobei area has good conditions for helium enrichment,which is a key area for coalbed helium resource exploration.While carrying out the coalbed helium resource census,it is suggested to strengthen the research on the exploration and enrichment law of helium resources in coal beds(rocks),provide technical support for the effective utilization of coal beds(rocks)helium in order t o keep the national helium resource security.