A method and apparatus for drilling wells in the ground layer composed of rock, clay and / or related materials

摘要

The invention relates to a method for drilling shafts (2) in ground layers (3). The method comprises of arranging a borehole casing (4) in the ground (3), lowering into the borehole casing (4) a hollow drill string (5) provided with a drill head (7) with cutting tools (8), arranging a water column (10) in the borehole casing (4), and then setting the drill string (5) into rotation (20) in the borehole casing (4) so that ground material (31) is dislodged by the cutting action of the cutting tools (8). At the position of the drill head (7) a first fluid (26) is injected under a first pressure into the ground layers (3) by means of one or more nozzles (25). The method has a higher drilling efficiency than the known method. The invention also relates to a device for performing the method, and a jack-up pontoon provided with the device.