Although CO₂-enhanced coalbed methane (CO₂-ECBM) recovery has been comprehensively investigated, fewer scholars have taken the effect of temperature into account, which brought a large deviation for the study of the influence of CO₂-ECBM. In this work, a hydraulic-mechanical-thermal coupled model of CO₂-ECBM is established, it combines binary gases (CO₂ and CH₄) infiltration and diffusion, where non-isothermal adsorption is also considered. The effect of injection pressure and reservoir initial temperature on CO₂-ECBM was simulated by the finite element simulation software COMSOL Multiphysics, results show that: the injection of CO₂ into coalbed has a good effect on enhancing the production of CH₄, and both the CO₂ storage rate and CH₄ production rate increase with the increase of injection pressure. The effect of initial reservoir temperature on CO₂-ECBM is obvious. Since the amount of adsorbed gas in coal decreases with the increase of temperature, the CO₂ storage rate and CH₄ production rate decrease with the increase of initial reservoir temperature. In the gas extraction process without CO₂ injection, the variation of permeability is competition result of two types of factors: the coal matrix shrinkage caused by temperature reduction and gas desorption increase, the other is the coal matrix expansion caused by gas pressure decrease, so the permeability follows the rule of first decreasing and then increasing with the extraction time. The injection of CO₂ has a great influence on the permeability of coalbed, adsorption of CO₂ by the coal matrix causes the permeability to drop rapidly.

尽管已经对CO ₂增强煤层气（CO ₂ -ECBM）的回收进行了全面的研究，但很少有学者考虑温度的影响，这为研究CO ₂ -ECBM的影响带来了很大的偏差。在这项工作中，建立了CO ₂ -ECBM的水力-机械-热耦合模型，该模型结合了二元气体（CO ₂和CH ₄）的渗透和扩散，其中还考虑了非等温吸附。用有限元模拟软件COMSOL Multiphysics模拟了注入压力和储层初始温度对CO ₂ -ECBM的影响，结果表明：注入CO ₂注入煤层对提高CH ₄的产量有很好的效果，CO _2的储藏速率和CH _4的产量均随注入压力的增加而增加。初始储层温度对CO ₂ -ECBM的影响是明显的。由于煤中吸附的气体量随温度的升高而减少，因此，CO _2的储存速率和CH _4的产生速率随初始储层温度的升高而降低。在无CO ₂的气体萃取过程中注入时，渗透率的变化是两种因素的竞争结果：温度降低和瓦斯解吸增加导致煤基质收缩，另一种是瓦斯压力降低导致煤基质膨胀，因此渗透率遵循先降后降的规律。然后随着提取时间的增加而增加。CO ₂的注入对煤层的渗透率有很大的影响，煤基质对CO ₂的吸附使渗透率迅速下降。