煤层气作为一种非常规天然气，其开发利用契合国家能源安全目标，更是对碳中和的一种助力。准南是我国重要的煤层气资源富集区之一，也是目前中国煤层气开发的热点地区，但高产井数量不多，稳产困难，迫切需要一种能够增加单井控制范围内煤层气资源量的技术；同时高CO₂和高H₂S体积分数已经成为该区煤层气的普遍现象，迫切需要一种原位处置这2种有害气体的技术，煤层气生物工程为此类煤层气的“提质增量”提供一种潜在可行技术。现场的跟踪监测以及实验室物理模拟试验表明，CO₂的体积分数与储层温度密切相关，产酸发酵细菌和产氢产乙酸菌能够在较为宽广的储层温度下保持活性而产生CO₂；而相对较低的储层温度下氢营养型产甲烷菌代谢较弱、CO₂很难被还原，这是该区CO₂的主要成因。此外发现地下水中携带的有机质、SO₄²⁻和原始菌群在运移过程中进行着代谢活动，随着排采的长期进行，当地下水补给速率、排采速率和产甲烷菌的代谢周期相匹配时，就会生成的H₂S，被称为后生生物H₂S。这2种酸性气体的存在，不仅影响安全生产，也大幅降低了煤层气的“质”。以准南低质煤层气为研究对象，提出了一种微生物介导的煤层气原位提质增量关键技术，并从必要性和可行性两方面阐述了该技术在煤层气增产、CO₂原位微生物转化、H₂S原位抑制方面的广阔前景。该技术的基本思路是将煤储层作为一个“车间”，微生物作为“劳动力”，将煤和原始储层中CO₂作为“生产资料”，制造的“产品”为甲烷，对于CO₂实现了生物甲烷化，对于H₂S实现了原位抑制，对于煤层气实现了提质增量。该技术涉及的关键挑战包括高效菌群的培养(培育温度范围宽广的氢营养型产甲烷菌)、H₂S原位抑制的生物压裂液研制以及提质增量的评价技术。物理模拟CO₂微生物甲烷化实验表明随着储层温度的增加，CO₂微生物累计甲烷化量逐渐增加，在55 ℃下达到最大值8.5 m³/t，参与该过程的糖酵解、丙酮酸代谢和TCA循环的关键酶的丰度在55 ℃下明显高于其他原位厌氧发酵系统，提高了CO₂的转化效率与转化量；添加生物抑制剂的非CO₂气氛厌氧发酵系统生物甲烷产量为4.5 m³/t，略高于对照组的4.38 m³/t；而气态H₂S的体积分数比对照组减少了88.8%，且从第9天开始到产气结束一直为0，实现了H₂S的原位抑制。

The development and utilization of coalbed methane (CBM) not only ensures national energy security, but also provides a boost to carbon neutrality. The southern edge of the Junggar Basin is a major CBM resource area and a key development hotspot in China. However, the region has few high-yield wells, and maintaining stable production is challenging. There is an urgent need for a technology that can increase the production of CBM resources within the control range of a single well. Additionally, high volume fractions of CO₂ and H₂S have become common in the CBM of this region, creating an urgent need for in-situ disposal technology for these gases. Coalbed gas bioengineering offers a promising technology for enhancing both the quality and production of CBM in this region. On-site monitoring and laboratory simulation experiments indicate that the CO₂ volume fraction is closely linked to reservoir temperature. Acid-producing fermentative bacteria and Hydrogen-producing acetic acid bacteria remain active and continue to produce CO₂ across a broad range of reservoir temperatures. At lower reservoir temperatures, the metabolism of hydrogenotrophic methanogens is weak and CO₂ is difficult to be reduced, which is the main reason for the high CO₂ volume fraction in this area. It was also found that the microbial community in the groundwater interacts with organic matter and ${mathrm{SO}}_4^{2-} $ during migration. H₂S is generated when the groundwater recharge and drainage rates are consistent with the metabolic cycle of methanogens, which is called epigenetic H₂S. The presence of these two acidic gases not only compromises production safety but also significantly reduces the quality of CBM. This study introduces a key technology for in-situ microbial-mediated enhancement of CBM quality and production, addressing the issue of low-quality CBM in southern Junggar Basin. The necessity and feasibility of this technology are discussed, highlighting its potential to enhance CBM production, facilitate in-situ microbial conversion of CO₂, and inhibit H₂S generation. The fundamental concept of this technology is to utilize the coal reservoir as an anaerobic fermentation site, with the coal and CO₂ present in the reservoir serving as fermentation substrates. This approach aims to achieve in-situ suppression of H₂S while enabling the biomethanation of CO₂. The key challenges of this technology include cultivating efficient microbial communities, especially hydrogenotrophic methanogens that can thrive across a wide temperature range, developing bio-fracturing fluids for in-situ H₂S suppression, and establishing effective evaluation methods for enhancing CBM quality. Physical simulations of CO₂ microbial methanogenesis showed that cumulative methane production by hydrogenotrophic methanogens increased with rising reservoir temperatures, reaching a peak of 8.5 m³/t at 55℃. At this temperature, the abundance of key enzymes involved in glycolysis, pyruvate metabolism, and the TCA cycle was significantly higher compared to other in-situ anaerobic fermentation systems, enhancing both CO₂ conversion efficiency. Furthermore, in an anaerobic fermentation system without CO₂ and with added biological inhibitors, biomethane production reached 4.5 m³/t, slightly higher than that of the control group (4.38 m³/t). Notably, the gaseous H₂S volume fraction was reduced by 88.8% compared to the control group. And the H₂S volume fraction was always zero from the 9^th day to the end of gas production during the anaerobic fermentation, achieving in-situ inhibition of H₂S.