Constraints and dynamic assessment of biomethane generation from cyclically nutrients stimulation

The generation of biomethane in geological history is primarily influenced by multi-stage tectonic uplift and diverse groundwater charging conditions. To investigate and simulate this process, we conducted laboratory experiments involving cyclic addition of nutrients. The results demonstrate that continuous nutrient supplementation is a viable approach for achieving sustained biomethane production, with yields ranging from 1191.53 to 1316.90 μmol/g over three biodegradation cycles. Fitzhugh models prove to be the most suitable for predicting biomethane production. Biodegradation induces rearrangement of coal's pore structure, leading to increased pore sizes and numbers, facilitating the infiltration of biological enzymes, and enhancing methanogenesis rates. Our study elucidates the mechanisms underlying biomethane generation in geological history and offers strategies to expedite the practical application of coalbed methane bioengineering.