水力压冲一体化增透抽采瓦斯技术

Hydraulic fracturing and punching integration enhanced permeability gas extraction technology

现有的水力压裂、水力冲孔、水力掏槽、水力割缝等煤矿井下水力增透技术工艺复杂、适应条件单一、劳动强度大,而钻冲一体化、钻扩一体化、水力冲/压一体化等技术对硬煤增透效果不理想,且存在工序繁琐、不能连续作业等问题。针对上述问题,提出了一种水力压冲一体化增透抽采瓦斯技术,在钻进过程中利用高压水射流定点(定向、分段)对煤层实施水力增透作业,可实现集打钻、对软煤水力冲孔及对硬煤水力喷射压裂的一体化作业。揭示了水力压冲一体化增透原理,即通过水力冲孔将软煤层的部分煤体冲出,实现软煤层出煤卸压增透,对硬煤层进行定点水力喷射压裂,实现硬煤层造缝增透;研制了水力压冲一体化钻具,满足高泵压、大排量的要求,具备较强的破岩和排屑能力,其工序简单、可操控性强;给出了高压水射流冲孔和水力喷射压裂时的钻具操控方法,探讨了钻进时冲压工艺和退钻时冲压工艺。在某矿16101底抽巷使用水力压冲一体化钻具进行了现场工程试验,结果表明:在软煤段进行水力冲孔作业,比传统水力冲孔缩短时间60%~80%,而单孔出煤量增加了约2倍,单孔平均百米瓦斯抽采纯量提高了1倍;在硬煤段进行水力喷射压裂作业,单孔平均百米瓦斯抽采纯量比传统水力冲孔提高了2倍。

The existing hydraulic fracturing,hydraulic punching,hydraulic slotting,hydraulic cutting and other underground hydraulic permeability enhancement technologies in coal mines have complex processes,single adaptability conditions,and high labor intensity.However,drilling and punching integration,drilling and expansion integration,hydraulic punching/fracturing integration and other technologies are not ideal for enhancing the permeability of hard coal.There are problems such as cumbersome processes and inability to operate continuously.In order to solve the above problems,a hydraulic fracturing and punching integration enhanced permeability gas extraction technology is proposed.During the drilling process,high-pressure water jet is used to perform hydraulic enhanced permeability operations on coal seams at fixed points(directional,segmented).It can achieve integrated drilling,hydraulic punching of soft coal,and hydraulic injection fracturing of hard coal.The study reveals the principle of hydraulic fracturing and punching integration permeability enhancement.The hydraulic punching is used to flush out part of the coal body in soft coal seams,achieving pressure relief and permeability enhancement of soft coal seams.The fixed-point hydraulic jet fracturing is performed on hard coal seams,achieving fracture formation and permeability enhancement in hard coal seams.The drilling tool of hydraulic fracturing and punching integration is developed to meet the requirements of high pump pressure and large displacement.The drilling tool has strong rock breaking and chip removal capabilities.The process is simple and controllable.The drilling tool control methods for high-pressure water jet punching and hydraulic jet fracturing are provided.The stamping process during drilling and stamping process during drill withdrawal are discussed.The on site engineering tests are conducted using fracturing and punching integration drilling tools in the 16101 bottom drainage roadway of a coal mine.The results show that hydraulic punching operation in the soft coal section shortens the time by 60%to 80%compared to traditional hydraulic punching.The coal output from a single hole increases by about 2 times,and the average gas extraction purity per 100 meters per hole increases by 1 time.The hydraulic jet fracturing operation is carried out in the hard coal section.The average gas extraction purity per 100 meters per hole increases by 2 times compared to traditional hydraulic punching.