煤层的低渗透性和甲烷的强吸附特征是制约煤层气开采的关键性问题，如何快速高效开采煤层气是目前煤层气开采研究中的重要课题。首先基于构建的水−气−热−固耦合数学模型，建立了煤层气注热开采的物理模型并验证了模型的正确性，然后从水气运移角度分析了注热方法的产气规律，最后在煤矿井下进行了现场注热试验。数值模拟结果表明：煤层气注热开采过程中水气运移遵循“前期排水，后期采气”的变化规律。煤层中的水对甲烷的解吸和运移产生了重要的影响。注热过程中水占据了甲烷的运移通道，水对甲烷的抑制作用大于温度的促进作用；注热后的抽采过程中，高温促进了甲烷的解吸，解除了水对甲烷的抑制作用，使煤层气的产量大幅度提高。通过现场注热试验，已经形成了2种成熟的井下注热强化煤层气开采方法，即间歇注热方法和交替注热方法。2种注热方法具有相似的产气规律，即注热阶段的日产气量和甲烷体积分数一般比较低，而注热后抽采阶段的日产气量和甲烷体积分数均大幅度提高。现场注热试验结果表明，与传统的负压抽采方法相比，间歇注热方法可以使甲烷的体积分数和日产气量分别提高10倍和100倍以上，交替注热方法可以使甲烷的体积分数和日产气量分别提高10倍和50倍以上。现场注热试验结果与数值模拟结果共同表明，注热强化煤层气抽采的效果显著，注热后抽采阶段是煤层气的高产时间段。

The low permeability of coal seams and the strong adsorption characteristics of methane are the key problems restricting the exploitation of coalbed methane (CBM). And how to exploit CBM quickly and efficiently is an important subject in the research of CBM mining. Firstly, based on the water- gas-heat-solid coupling mathematical model, a physical model of heat injection enhanced CBM extraction was established and the correctness of the model was verified. Then, the migration mechanism of water-gas two phase in the process of heat injection was studied through numerical simulation software. Finally, it was applied in the coal mine. The numerical simulation results show that the gas-water migration in the process of heat injection enhanced CBM drainage follows the changing law of “drainage in early stage and gas extraction in later stage”. The water in the coal seam has an important influence on the migration of methane. During heat injection, water occupies the migration channel of methane, and the inhibition of water on methane is greater than the promotion of temperature, resulting in the reduction of CBM production. After heat injection, high temperature promotes methane desorption and relieves the inhibition of water on methane, resulting in a significant increase in CBM production. Through the heat injection test in coal mine, two mature heat injection methods have been formed, namely intermittent heat injection method and alternate heat injection method. The two heat injection methods have similar gas production laws, that is, the daily gas production and methane concentration in the heat injection stage are generally low, while in the extraction stage after heat injection they are significantly increased. The field test results show that compared with the traditional negative pressure extraction method, the intermittent heat injection method can increase the methane concentration and daily gas production by more than 10 times and 100 times respectively. Also, the alternative heat injection method can increase the methane concentration and daily gas production by more than 10 times and 50 times respectively. Finally, the results of both field test and numerical simulation show that the effect of heat injection enhancing CBM extraction is significant, and the extraction stage after heat injection is a high yield period of CBM. The research results can provide a theoretical basis and technical guidance for the engineering practice of CBM extraction by heat injection.