自进式水射流钻进技术在煤层气开发中的应用

自进式高压水射流钻进技术是在煤层气勘探井内布置机械或水力扩孔装置,对准选定的煤层进行扩孔后,下入特制的转向工具,在300mm的曲率半径内实现由垂直转向水平进行钻进.自进式钻头由旋转喷嘴、钻屑整合装置及推力提供装置等组成,其带动为其提供高压水动力的特制胶管向前连续钻进.高压水通过高压胶管为自进式钻头提供动力,进行钻进、推动及排渣.该技术可以在同一煤层气勘探井内的不同煤层内完成多个水平钻孔,这些径向水平钻孔可以沟通新的瓦斯流动通道,从而大幅度地提高煤层气产量.

Application of self-advanced water jet drilling technology in coalbed methane exploration

Self-advanced high pressure water jet drilling technology is to use mechanical or water jet apparatus to form a cavity at the selected coal seam,a specially made whip-stock is then to be installed in the cavity to drill inseam horizontal holes from the vertical well.A self-advanced drilling head consists of spinning jet nozzles,cutting treatment apparatus and thrust providing apparatus etc.The drilling head drags the high pressure water hose to form holes continuously.High pressure water flows through the hose to provide drilling power and propelling thrust as well as flush coal cuttings out of the well.Using this technology can bore a number of radial holes at different coal seams from the single well.As the horizontal inseam holes form new methane flow passages,the space of vertical wells can be significantly increased by drilling these radial boreholes thus dramatically increases the methane production.