【摘要】 针对单一地面井或井下钻孔抽采瓦斯效果不理想的问题,提出了在地面井煤层压裂增渗的同时,结合井下长钻孔部署的局部范围卸压增渗的方法,使煤层渗透性得到双重提高,进而取得较好的抽采效果。评价了人工裂缝监测技术对地面井煤层压裂的裂缝形态和有效半径,考察了试验区瓦斯含量、百米钻孔瓦斯流量、瓦斯抽采量及浓度等相关参数。结果表明:地面井压裂影响范围呈椭圆区间,长半轴一般为70~100 m,短半轴20~30 m;压裂影响区瓦斯抽采量及浓度明显提高,但随着时间的推移压裂效果逐渐降低。更多还原

【Abstract】 According to the problem of single surface well or a borehole in underground mine applied to drain the gas was irrational in effect,the paper proposed that while the fracturing and permeability improvement conducted in the coalbed methane surface well,in combination with the gas pre-drainage technology with long distance boreholes set for the pressure releasing and permeability improvement in a local scope,thus the seam permeability was doubly improved and a considerable drainage effect was realized. The micro seismic,underground mine observation method and other crack manual monitoring and measuring technology were applied to evaluate the crack form and effective radial of the surface well fracturing.The gas content of the test zone,gas flow of 100 m borehole,gas drainage quantity,gas concentration,outburst danger index and other related parameters were investigated.The results showed that the influence scope of the surface well fracturing was in an elliptic interval,a major semi-axis was 70 ~ 100 m generally,minor semi-axis was 20 ~ 30 m and the crack form was vertical crack mainly.The gas drainage value and concentration from the fracturing affected zone were obviously improved.After the fracturing conducted,the percentage of the high outburst prevention index was highly reduced,but the fracturing effect would be steadily reduced with the time passed.更多还原