The effect of Cenozoic basin inversion on coal-bed methane in Liupanshui Coalfield, Southern China

Coalbed methane (CBM) is an important energy source globally, thus understanding its origin and evolution essential to the assessment of reserves developing exploration strategies. This study aims identify CBM in Liupanshui Coalfield (LPC) southern China evaluate influence basin exhumation on gas storage different rank coals. Ten samples were collected from four blocks that have thermal histories coal ranges. Based C 1 /(C 2 + 3 ) ratio (16–971), ? 13 CH4 (?41.6 ?34.9‰) ?D (?185 ?140‰), mainly thermogenic origin. Systematic compositional differences between are consistent with maturity. Noble gases LPC a mixture air-derived dissolved local groundwaters radiogenic generated coals diffused deeper crust. The 4 He/ 40 Ar ? 21 Ne / lowest Qingshan block, strong evidence diffusive loss light noble gases. 20 Ne/ 36 (0.23–0.70) all higher than air-saturated water (0.16) most easily explained by re-dissolution exsolved groundwater during inversion. 84 Kr/ 132 Xe/ ratios predicted this process likely reflect desorption Xe Kr has been trapped matrix at time formation. exsolution reservoir Mesozoic-Cenozoic Modelling both free adsorbed inversion we find block lost highest proportion (77%), yet total (free adsorbed) (25%) due adsorption capacity mature volume interacted phase estimated according model role preservation extraction. Combining production data for blocks, high content efficient extraction expected maturity seen low but more shallow depth. • Methane water-gas volumetric used production.