复杂地质低渗煤层水力压裂-割缝综合瓦斯增透技术研究

针对水力压裂区域化瓦斯增透盲区，提出了水力割缝局部化瓦斯增透技术措施，形成了复杂地质低渗煤层水力压裂-割缝综合瓦斯增透技术，并进行现场验证。研究结果表明:水力压裂区内的3个压裂钻孔平均瓦斯抽采纯流量较238底板道常规抽采钻孔单孔瓦斯抽采纯流量提高15.8倍，瓦斯抽采浓度提高4%，压裂区瓦斯抽采纯流量较对比区提高2.1倍，但水力压裂区域性措施受断层及煤层硬度等地质条件限制，存在盲区；水力割缝增透区内的抽采钻孔瓦斯浓度平均提高4.9倍，瓦斯纯流量平均提高3.3倍，对不同地质条件的适应性强，但是割缝影响范围小，抽采时效短；复杂地质低渗煤层水力压裂-割缝综合瓦斯增透技术综合了水力压裂与割缝的优点，对复杂地质煤层具有较强适应性，大幅提高了瓦斯治理水平。现场验证结果表明复杂地质低渗煤层水力压裂-割缝综合瓦斯增透技术在复杂地质条件下煤层强化抽采中有较好的实际应用价值。

Research on comprehensive gas permeability improvement technology by hydraulic fracturing and slotting in coal seam with complex geological conditions and low permeability

Aiming at the problem of gas drainage in the coal seam with complex geological conditions and low permeability in Baijiao Coal Mine, the hydraulic fracturing technology was applied to carry out the regional gas permeability improvement, and its application effect was analyzed according to the situation of field gas drainage. Aiming at the blind area of regional gas permeability improvement by hydraulic fracturing, the technical measure of localized gas permeability improvement by hydraulic slotting was put forward, then the comprehensive gas permeability improvement technology by hydraulic fracturing and slotting in coal seam with complex geological conditions and low permeability was formed, and the field verification was conducted. The results showed that the average pure flow rate of gas drainage for three fracturing boreholes in the hydraulic fracturing zone increased by 15.8 times than that of regular single borehole gas drainage in 238 floor laneway, and the gas drainage concentration increased by 4%. The pure flow rate of gas drainage in the fractured area increased by 2.1 times than that of the comparison zone, but there existed the blind area by the regional measures of hydraulic fracturing due to the restriction of geological conditions such as fault and coal seam hardness. The gas concentration of drainage borehole in the hydraulic slotting permeability improvement zone increased by 4.9 times on the average, and the pure flow rate of gas increased by 3.3 times on the average. It has strong adaptability to different geological conditions, but the influence range of slotting is small, and the drainage time is short. The comprehensive gas permeability improvement technology by hydraulic fracturing and slotting in coal seam with complex geological conditions and low permeability integrates the advantages of hydraulic fracturing and slotting, and it has strong adaptability to coal seam with complex geological conditions, which improves the gas control level greatly. The field verification results showed that this technology has better practical application value for enhanced gas drainage in coal seam with complex geological conditions.