Background Helium, a strategic resource in short supply, primarily occurs in natural gas. In China, helium resource assessment remains in its nascent stage, and limited helium exploration and exploitation have been conducted in general. Most especially, for regions experiencing no natural gas exploration and basins where helium reserves remain unproven, it is essential to develop reliable methods for helium resource evaluation. Among various approaches, genesis methods, based on models of helium generation, migration, and enrichment processes, offer advantages including simple models, accessible parameters, and rapid assessment. However, existing genesis methods focus primarily on the estimation of the total amount of generated helium from a single helium source rock, generally neglecting the characteristic of multi-source helium generation, the helium release efficiency of source rocks (i.e., helium expulsion coefficient), and helium migration and enrichment efficiency (i.e., migration–accumulation coefficient). These omissions tend to induce overestimated resources and reduced accuracy.
Methods This study developed a genesis method-based, systematic methodology for helium resource evaluation. The helium expulsion coefficient and migration–accumulation coefficient were innovatively introduced into the new methodology based on helium genesis theories. Furthermore, methods for determining the values of various parameters were proposed through field observations and laboratory analyses. Finally, the new methodology was applied to the Jinzhong Basin for verification.
Results and Conclusions A formula for calculating helium resources based on the genesis method was established, and methods for determining the parameters in the formula were also proposed. Experiments and calculations of representative helium-rich basins and gas fields in China and abroad reveal that various helium source rocks exhibit helium expulsion coefficients exceeding 80% and that stable helium accumulation systems show a maximum migration-accumulation coefficient of 3.7%. The new methodology was applied to the Jinzhong Basin, revealing that the total amount of generated helium from helium source rocks in the basin is 55.6 billion m3 and that the helium resources produced by the helium accumulation systems since their formation are 0.34 billion m3. The proposed methodology enriches the helium resource evaluation system of China, providing a methodological basis for helium resource evaluation in areas undergoing limited helium exploration. Medium-small basins in China, exemplified by the Jinzhong Basin, generally contain helium and thus hold great helium resource potential. These basins are expected to become significant potential regions for achieving helium exploration breakthroughs in the future.
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