甘肃省首个高品位氦气盆地的发现及勘探前景

THE FIRST DISCOVERY AND EXPLORATION PROSPECT OF HIGH GRADE HELIUM BASIN IN GANSU PROVINCE

氦是关系国家高新技术产业发展和国家安全的重要战略性稀有气体资源,全球每年氦气需求量约为22亿m^(3),但年产量仅有17亿m^(3),长期严重短缺。我国氦气年需求量约2 200万m^(3),而四川威远含氦天然气年产氦气29.2万m^(3),仅相当于2017年氦气进口量的1.45%。陕西省在渭河盆地发现水溶性氦气资源后,于2019年在渭南、咸阳建成了提氦试验站,预期一定程度上可缓解氦气资源的短缺;甘肃省在民和盆地开展石油地质和地热资源勘查时发现了高品位氦气资源,通过对其成藏条件研究,认为氦气产于含U、Th的酸性花岗岩,其富集受地热、烃源岩、断裂等控制明显,通过对地热水取样、分析,首次发现含量为0.77%~1.5%的高品位氦气(工业品位0.3%,威远气田氦气品位仅为0.2%);盆地周缘和基底赋存有规模较大的高放射性花岗岩,研究认为民和盆地氦气资源成藏富集条件良好,具有一定的勘探前景。

Helium is an important strategic rare gas resource related to the development of national hightech industry and national security. The global annual helium demand is about 2. 2 billion m^(3), but the annual output is only 1. 7 billion m^(3), which is seriously short for a long time. China’s annual demand for helium is about22 million m^(3), while the annual output of helium of helium bearing natural gas in Sichuan Weiyuan is 292 000 m^(3), which is only equivalent to 1. 45% of helium import in 2017. The shortage of helium resources can be alleviated after the discovery of water-soluble helium resources in Weihe Basin and Shaanxi Province has built helium extraction test stations in Weinan and Xianyang in 2019;Gansu Province has found high-grade helium resources in the exploration of geothermal resources in Minhe Basin. It is considered that the helium is produced in acid granite containing U and Th, whose enrichment is obviously controlled by geothermal, hydrocarbon source rock and fracture. Through fine sampling and analysis of geothermal water, high-grade helium(industrial grade is0. 3%, Weiyuan gas field’s helium grade is only 0. 2%) with content of 0. 77% ~ 1. 5% is found for the first time;There are large-scale high-radioactive granites in the periphery and basement of Minhe Basin, which means it has a better prospect of helium resources from the aspect of reservoir forming conditions.