低透气性煤层致裂增透技术应用与展望
Application and prospects on fracturing and permeability improved technology of mine low permeability seam
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摘要: 为了实现煤层气的工业化利用,分析了三维高压旋转水射流扩孔煤层增透技术、定向分段水力压裂增透技术、高压空气爆破致裂煤层技术的增透效果,应用上述煤层致裂增透新技术后,煤层气抽采量明显增加。高压水通过三维旋转钻头对煤体快速切割迅速破坏煤体,实现对影响区域内煤层气的快速释放;特制封孔器将压裂孔分割为数段,增大压裂面积的同时最大限度地利用高压水能,大幅增加了煤层气的逸出通道;经过加压的高压空气可实现对目标钻孔的连续爆破,大幅增加了煤层的煤层气的逸出通道,经济成本低。由于物理破坏增透方式存在着能量损失大、裂纹扩展方向有一定的随机性、预期方向有一定的偏差等问题,提出研发能溶解部分煤基质溶剂结合物理破坏方式以增加煤层的透气性。Abstract: 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.