Gas drainage efficiency improvement by increasing coalbed permeability using waterjet cutting system

摘要

This paper presented a method to create artificial fractures along the existing gas drainage borehole and increase the permeability of the coalbed using a high pressure waterjet cutting system. The field work conducted in Rujigou Colliery, Shenhua Ningxia Coal Group demonstrate that the coalbed permeability is increased, and accordingly, gas drainage efficiency is improved up to 3 to 6 times over the traditional methods using high pressure waterjet technique. Also, based on the monitoring data, the conceptual model for gas drainage process associated with different mining activities has been proposed, and few major advantages using waterjet assistance method have been identified.