超临界CO2参与下煤储层原位微生物甲烷化物理模拟研究

超临界CO₂能够破坏煤分子结构，提高生物甲烷的产量。为研究微生物在超临界CO₂参与的煤储层原位条件下的产气潜力，以新疆地区某煤层气区块目标煤层的初始储层压力、温度和气体组分作为原位储层条件，通过自主设计的煤储层原位厌氧发酵装置，模拟煤储层原位储层条件下的厌氧发酵过程，并对生物气产量、煤的官能团结构和微生物群落结构进行了分析。研究结果表明，在超临界CO₂参与的煤储层原位条件下，生物甲烷产量达到了32.9 mL/g，CO₂的生物转化率为17.4%。FTIR光谱表明，原位条件下微生物对苯酚、醇、醚、酯中含氧基团的降解能力要强于常规条件下的厌氧发酵。超临界CO₂参与下的储层原位厌氧发酵系统中，多种产甲烷代谢途径的产甲烷菌(氢营养型、乙酸营养型和甲基营养型)逐渐向单一的氢营养型产甲烷菌演化。高压环境下，细菌群落中芽孢杆菌Solibacillus silvestris成为水解产酸发酵阶段的优势菌。该研究为煤层气生物工程的现场实施和碳减排提供了实验基础。 

Physical simulation of in-situ microbial methanation in coal reservoirs with the participation of supercritical CO2

Supercritical CO₂ can destroy the molecular structure of coal and increase the production of biomethane. To investigate the gas production potential under the in-situ conditions of coal reservoirs with the participation of supercritical CO₂, the original reservoir pressure, reservoir temperature, and gas composition of the target coal seam in a coalbed methane block in Xinjiang were used as the in-situ reservoir conditions. The self-designed anaerobic fermentation device for coal reservoirs was used to simulate the in-situ anaerobic fermentation process, and the biogas production, coal surface functional groups and microbial community structure under the in-situ conditions were analyzed. The results show that under the in-situ conditions of coal reservoirs with supercritical CO₂, the biomethane production reaches 32.9 mL/g, and the CO₂ bioconversion rate is 17.44%. FTIR spectroscopy shows that the ability of microorganisms to degrade oxygen-containing groups in phenol, alcohol, ether and ester under in-situ conditions is stronger than that under the conventional anaerobic fermentation conditions. In the in-situ anaerobic fermentation system with the participation of supercritical CO₂, methanogens with multiple methanogenic metabolic pathways (hydrogenotrophic, acetic acidotrophic and methylotrophic) gradually evolved to single hydrogenotrophic methanogens. Under high pressure, the genus of Solibacillus silvestris became the dominant bacteria in the fermentation stage of hydrolysis and acid production. This article provides an experimental basis for the on-site implementation of coalbed gas bioengineering and carbon emission reduction.