Ding Xin, Hou Jing, Xiao Xiaochun
School of Mechanics and Engineering, Liaoning Technical University, Fuxin, 123000, China.
Liaoning Key Laboratory of Mining Environment and Disaster Mechanics, Liaoning Technical University, Fuxin, 123000, China.
Sci Rep. 2022 May 11;12(1):7768. doi: 10.1038/s41598-022-11948-5.
The present study proposes the use of a new ultrasonic irradiation method to enhance permeability and desorption for gas recovery from low-permeability coal reservoirs. A triaxial stress ultrasonic irradiation test apparatus was developed specifically for coal, considering the properties of gas adsorption, migration, and sound intensity, and providing a simultaneous measurement of gas flux, to investigated the deformation and temperature of coal samples obtained from the Fuxin coal field by permeability and desorption experiments. With the ultrasonic irradiation duration, the permeability of coal improved gradually with unequal variation, accompanied by the Klinkenberg effect where it decreased rapidly and then increased slowly with increasing gas pressure. The ability to desorb coal was enhanced by higher sound intensity ultrasound irradiation, and the volume of gas desorption was much greater than that of the sample without mange, the temperature and strain were demonstrated as a "J shaped" curve. An X-ray computer tomography (CT) technique was used to visualise the meso- or macro-cracks in the coal sample at pre- and post- ultrasonic irradiation, consequently, fractures expanded under the irradiation of ultrasonic waves. A permeability and desorption model was developed to describe the improvement of coal seam gas production capacity under ultrasonic irradiation, which introduced effective sound pressure.
本研究提出采用一种新的超声辐照方法来提高低渗透煤储层气体采收率的渗透率和解吸率。考虑到气体吸附、运移和声音强度的特性，专门为煤开发了一种三轴应力超声辐照试验装置，并同时测量气体通量，通过渗透率和解吸实验研究了取自阜新煤田的煤样的变形和温度。随着超声辐照时间的延长，煤的渗透率呈不均匀变化逐渐提高，伴随克林肯贝格效应，即随着气体压力的增加，渗透率先迅速下降然后缓慢上升。较高声强的超声辐照增强了煤的解吸能力，气体解吸量远大于未处理样品，温度和应变呈“J形”曲线。利用X射线计算机断层扫描（CT）技术对超声辐照前后煤样中的细观或宏观裂缝进行可视化，结果表明，超声波辐照下裂缝扩展。建立了渗透率和解吸模型来描述超声辐照下煤层气产能的提高，该模型引入了有效声压。
