ABSTRACT Helium‐rich coalbed methane (CBM) represents a promising new target for boosting helium production, and gas exsolution from groundwater is a critical process for helium accumulation. Ion compositions of groundwater generally affect gas solubility, but the coupling relationships among helium and other components in CBM controlled by hydrogeochemical compositions remain unclear. To clarify the gas–water interactions and their effects on helium concentration variations in coal measure systems, in this study, gas and water samples from 16 CBM wells were collected for geochemical experiments, with supplementary simulations of helium exsolution induced by CO 2 /N 2 injection. Gas provenance analysis indicated mixed thermogenic‐biogenic CH 4 , biogenic CO 2 , crustal helium and N 2 primarily of atmospheric genesis. Helium concentrations reached a maximum of 0.97%, with an average of 0.12%. The helium concentration showed parabolic correlations with CO 2 and N 2 concentrations, a pattern attributed to the dilution effects exerted by elevated CO 2 and N 2 concentrations. Following equal‐duration interactions with CO 2 and N 2 , helium‐containing aqueous solutions produced gaseous helium concentrations of 16.52% and 2.16% respectively, suggesting that CO 2 plays a more significant role in the helium enrichment. Considering the generation and migration of CBM, the helium, N 2 and CO 2 concentrations displayed zonal variations controlled by hydrogeochemical fields. Under similar geological conditions, the biogenic CH 4 and mixed CH 4 areas in runoff or weak runoff zones exhibit enhanced helium enrichment potential. This study established an innovative distribution model for helium, CO 2 and N 2 in CBM controlled by hydrochemical compositions, which advances the understanding of the hydrological processes associated with helium enrichment.
Zhang et al. (Sun,) studied this question.