煤层脉动水力压裂卸压增透技术研究与应用

为了提高高瓦斯低透气性煤层瓦斯的抽采效率，提出了煤层脉动水力压裂卸压增透技术，进行了不同压力、频率条件下型煤试样的脉动水力压裂实验，分析了脉动水作用下煤体的疲劳损伤破坏特点及高压脉动水楔致裂机理。研究结果表明：煤体原生裂隙在强烈的脉动水压力作用下，会在缝隙末端产生交变应力，使煤体裂隙孔隙产生“压缩-膨胀-压缩”的反复作用，煤体将产生疲劳损伤破坏，煤体内部裂隙弱面扩展、延伸，形成相互交织的贯通裂隙网络。工业性试验结果表明脉动水力压裂比普通水力压裂卸压增透效果明显，钻孔瓦斯抽采浓度和流量均有较大幅度提高。

Research and application of coal seam pulse hydraulic fracturing technology

In order to improve the gas drainage efficiency of high gas and low permeability coal seams，the pulse hydraulic fracturing technology was proposed，hydraulic fracturing experiments and mechanical analysis were taken under different pressures and frequencies，and fatigue damage characteristics of coal and the mechanism of high pressure pulse hydraulic fracturing were analyzed too.The results show that alternating stress is formed at the end of coal fracture under the action of the intense pulse water，and fatigue damage failure can be formed in the coal due to repeated action of compression expansion compression.The extension of fracture and weak plane in the coal is transformed into interlaced transfixion fracture network.Compared with general methods of hydraulic fracturing，the results of industrial experiments show that pulse hydraulic fracturing generates a better effect of pressure relieving and permeability improving，meanwhile，the concentration and flow of drilling gas extraction are remarkably improved.