当前国内外尚无系统的氦气资源评价方法以及针对性的参数取值标准。通过天然气和氦气的成藏要素对比,明确了载体气和壳源氦气的异源同储、同源同储和同源异储3类共生关系,以及壳源氦气成藏的8个关键因素。构建了4类10种氦气资源分级分类评价方法,其中含量法包括5个亚类,统计法包括1个亚类,类比法包括3个亚类,成因法1个亚类,初步解决了氦气资源定量计算的难题。结果表明:高氦气含量的气藏一般为常压及低压气藏,氦气含量与氦源岩类型、铀钍含量和氦源岩规模3个参数呈正向关系,而与离主断裂距离、埋深和生烃强度3个参数呈负相关,适度的基底构造活动有利于氦气释放及富集。基于8类氦气成藏主控因素与氦气含量的定量关系,建立了氦气含量类比法。基于异源同储不同序的原理,构建了氦气资源规模序列法;基于放射性元素衰变释氦机理,建立了氦气成因法。氦气资源评价方法在国内外得到了较为广泛的应用,研究成果将为我国氦气储量规模发现提供了有效支撑。

Presently there is no systematic helium (He) resource evaluation method, nor evaluation parameter standard. This study, by comparing the accumulation controlling factors of natural gas and crustal helium, identifies eight key controlling factors of crustal helium accumulation and three co-occurrence styles between carrier-gas and helium, namely, different sources in one reservoir, same source in one reservoir, and same source in different reservoirs. For preliminary quantitative evaluation of helium resource, four classification and evaluation methods using ten different algorithms are established—with percentage method using five; statistical method, one; analogy method, three; and genetic method, one. Helium-rich gas reservoirs are generally characterized by normal to low pressure. The helium content is positively correlated with three parameters—source type, U/Th contents, and source rock volume, and negatively correlated with three parameters—distance from the main fault, burial depth, and hydrocarbon-generating intensity; while moderate basal tectonic activity is conducive to helium release and enrichment. Analogy method is established based on the quantitative relationships between the eight key factors and helium content. Scale sequence method is based on the principle that gases from different sources in one reservoir have different scale sequences. And genetic method is based on the radioactive decay model of helium release and accumulation. The evaluation methods are used widely both at home and abroad, and their application shall effectively contribute to the discovery of large-scale helium reserves in China.