Experimental study on permeability response of structural coal to infrared radiation power

The geological mining conditions of coal reservoirs in China are complex because of the characteristics of low pressure, low permeability, low saturation, and high gas content. Many scholars have studied the CBM stimulation technology through various means to achieve the purpose of highspeed exploitation of CBM. However, due to the unclear mechanism of desorption and seepage in coal seams, a largescale mining has not been realized. Through the temperature rise experiment, the temperature change law of the coal sample under infrared radiation was revealed. The greater the infrared radiation power is, the faster the temperature rise rate of the coal sample is, and the higher the temperature can be achieved. The relationship between coal sample temperature and infrared radiation power was obtained. The relationship provides a reference for exploring the temperature rise law of coal samples under infrared radiation and subsequent desorption seepage experiments under infrared radiation. The desorption seepage experiment of coal samples was carried out based on the infrared radiation triaxial loading experimental system with independent intellectual property rights. The system is mainly divided into the infrared radiation subsystem, threeaxis loading subsystem, and data acquisition subsystem. The permeability of coal samples was systematically studied with axial pressure, confining pressure, pore pressure, and infrared radiation power as variables, the problem that infrared field, stress field, and seepage field cannot be loaded at the same time was solved. The experimental system has the characteristics of simple structure, high safety, good sealing, large pressure range, stable numerical value, and independent regulation of parameters. Based on the existing research, the coal sample seepage experiment under the action of infrared radiation was conducted to quantitatively analyze the relevant parameters and evolution law in the process of coal sample desorption seepage. The results show that in the range of low pore pressure, the permeability of coal samples increases with the infrared radiation power and the maximum permeability increases by 45%. Under the same pore pressure, the coal sample is in a state of low confining pressure, and the permeability is generally higher than that of high confining pressure. The relationship between coal sample permeability and infrared radiation power was derived, and the porosityrelated parameters and thermal expansionrelated parameters in the relationship were analyzed, under the influence of infrared radiation, porosityrelated parameters decrease with the increase of confining pressure. When the pore pressure is constant, the variation range of coal expansionrelated parameters with the increase of confining pressure is between 0.004 5 and 0.003 0. The permeability loss rate of coal under the action of infrared radiation was analyzed, under the condition of low pore pressure, the permeability loss rate of coal samples decreases with the increase of infrared radiation power. Considering the infrared radiation power sensitivity, under the condition of certain pore pressure, the infrared radiation power sensitivity coefficient of coal permeability is positively correlated with the infrared radiation power. Under the condition of different pore pressures, the power sensitivity of coal permeability is different, The power sensitivity coefficient is not only related to the infrared radiation power, but also to the result of the joint action of pore pressure and confining pressure. By analyzing the influencing factors of coal sample permeability under the action of infrared radiation, the fixed relationship and influencing parameters were obtained.