Abundance characteristics, enrichment properties, and source analysis of helium in coal seam gas from the Luling coal mine in Huaibei coalfield, China

This study has conducted an analysis of the helium abundance, enrichment mechanisms, and sources in coalbed methane (CBM) from the Luling coal mine in the Huaibei Coalfield, China. Geochemical testing results indicate that the helium concentration in the coalbed methane is significantly higher than atmospheric levels but below the threshold for industrial exploitation, indicating that the reservoir is helium-lean and remains below commonly cited commercial extraction thresholds order of ~0.1% He, noting that economic cutoffs may vary by region and processing context. Analysis of helium isotope ratios reveals a mixed crust-mantle origin, with a notable contribution from mantle-derived fluids formed under the influence of the deep Tanlu Fault Zone. A strong positive correlation between helium and nitrogen suggests a common deep-seated origin for both elements, along with coupled migration and enrichment. These findings not only provide crucial insights into the helium generation mechanisms in coalbed methane systems within stable cratonic tectonic settings but also offer an important reference for helium resource exploration in similar geological environments.