Permeability Enhancement Properties of High-Pressure Abrasive Water Jet Flushing and Its Application in a Soft Coal Seam

Frontiers in Energy Research

Sławomir Dykas¹  Piotr Wiśniewski¹  Xinzhe Zhang²  Guojie Zhang³ 

[1] Department of Power Engineering and Turbomachinery, Silesian University of Technology, Gliwice, Poland;School of Aeronautical Engineering, Zhengzhou University of Aeronautics, Zhengzhou, China;School of Mechanical and Power Engineering, Zhengzhou University, Zhengzhou, China;School of Mechanical and Power Engineering, Zhengzhou University, Zhengzhou, China;

关键词: CFD;    experimental study;    permeability enhancement;    numerical study;    high-pressure abrasive water jet flushing;   

DOI  :  10.3389/fenrg.2021.679623

来源: Frontiers

【 摘 要 】

High-pressure abrasive water jet flushing (HPAWJF) is an effective method used to improve coal seam permeability. In this study, based on the theories of gas flow and coal deformation, a coupled gas-rock model is established to investigate realistic failure processes by introducing equations for the evolution of mesoscopic element damage along with coal mass deformation. Numerical simulation of the failure and pressure relief processes is carried out under different coal seam permeability and flushing length conditions. Distributions of the seepage and gas pressure fields of the realistic failure process are analyzed. The effects of flushing permeability enhancement in a soft coal seam on the gas drainage from boreholes are revealed by conducting a field experiment. Conclusions can be extracted that the gas pressure of the slotted soft coal seam is reduced and that the gas drainage volume is three times higher than that of a conventional borehole. Field tests demonstrate that the gas drainage effect of the soft coal seam is significantly improved and that tunneling speed is nearly doubled. The results obtained from this study can provide guidance to gas drainage in soft coal seams regarding the theory and practice application of the HPAWJF method.

【 授权许可】

CC BY