煤层水力压裂增透技术研究

Research on hydraulic fracturing antireflection technology of coal seam

针对低渗透高瓦斯煤层,为了强化煤层瓦斯抽采效果,对煤层水力压裂注水压力对压裂效果的影响进行了模拟分析,并通过现场试验验证了模拟结果。经模拟,水压的增大对煤岩压裂效果起到促进作用,19.5 MPa水压能使煤层产生良好的裂纹扩展效果。经现场试验验证,压裂后,初始瓦斯涌出量是自然抽采孔的4.49倍,瓦斯流量衰减系数由0.035 8 d^(-1)降低至0.008 34 d^(-1),瓦斯流量衰减降幅达到76.71%,煤层透气性系数最大提升约为原来的44倍,表明水力压裂增透技术具有良好的煤层促抽效果。

Aiming at the low permeability and high gas coal seam,in order to strengthen the effect of coal seam gas extraction,the influence of water injection pressure on the fracturing effect of coal seam hydraulic fracturing was simulated and analyzed,and the simulation results were verified by field test.Through simulation,the increase of water pressure promotes the fracturing effect of coal rock,and 19.5 MPa water pressure can make the coal seam produce good crack propagation effect.The field test shows that after fracturing,the initial gas emission is 4.49 times that of the natural drainage hole,the attenuation coefficient of gas flow decreases from 0.035 8 d^(-1) to 0.008 34 d^(-1),the attenuation of gas flow decreases by 76.71 %,and the maximum increase of coal seam permeability coefficient is about 44 times that of the original,indicating that the hydraulic fracturing and permeability increasing technology has a good effect on promoting drainage of coal seam.