Application and prospects on fracturing and permeability improved technology of mine low permeability seam

In order to realize an industrialized utilization of the coalbed methane, an analysis was conducted on a permeability improved technology with a 3D high pressure rotary water jet to ream the borehole in the seam, a permeability improved technology with directional section hydraulic fracturing and high pressure air blastin g fracturing technology of the seam. After the fracturing and permeability improved technology applied, the coalbed methane drainage volume was obviously increased. With the 3D rotary drilling bit, the high pressure water could rapidly cut the coal mass and could rapidly damage the coal mass and could rapidly release the coalbed m ethane affected to the region. The special made packer could divide the fractured borehole into several sections, could enlarge the fracturing area with a max utilization of the high pressure water energy and could highly increase the released channels of the coalbed methane. The pressurized high pressure air could realize a continued blasting in a target borehole, could highly increase the coalbed methane released channels in the seam and could have a low economic cost. Due to the physical failure and permeability improved method had a high energy lost, the cracking expansion direction with a certain random and the expectations with certain deviation problem, t he research and development was provided on the technology to dissolve the partical coal based solvent combined with the physical failure, so as to improve the perme ability of coal seam.