Mechanism and research progress of ultrasonic excitation flow enhancement in low permeability coal seam
Shugang Li, Ruizhe Wang, Min Yan, Yue Qiu, Haifei Lin, Xiaoying Zhang, Xing Zhou
Abstract
Abstract Ultrasonic excitation permeability enhancement technology has attracted great attention in the field of coal seam permeability enhancement. This technology has the characteristics of no pollution and low energy consumption. According to the thermal effect, cavitation effect and mechanical vibration effect of ultrasonic wave when ultrasonic wave propagates in two-phase or even multi-phase medium, the triple effect can achieve the purpose of fracturing coal body. It can effectively change the pore and fracture structure of coal and improve the permeability of coal seam. It has become an effective permeability enhancement technology. In this paper, the research work of ultrasonic excitation of coal is summarized from the aspects of theoretical analysis and laboratory test. From the perspectives of pore structure, macro fracture structure and mechanical damage behavior response of coal under ultrasonic excitation, the influence of key parameters of ultrasonic excitation on the desorption and seepage of coal gas is analyzed. Combined with the research work of the author's research team and the latest research progress at home and abroad, the bottleneck problems and directions that need to be solved urgently in the application of ultrasonic excitation current increasing technology in low permeability coal seams are pointed out, and a new idea for the application of ultrasonic excitation current increasing technology in coal seam gas extraction is proposed. It is of great scientific significance in the development of deep coal seam gas resources and disaster prevention and control.