| 摘要 |
A drill tool comprising a drill pipe having a turbine and a hydraulic pump, wherein drilling fluid is passed through the turbine and into the hydraulic pump through a hollow shaft in the drill pipe. The drill tool also includes a high pressure jet at a distal end of the drill pipe for discharging drill fluid at a pressure which is between 20 and 40 MPa greater than the ambient pressure of the drill hole.
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