| 摘要 |
<p>A method for underwater drilling, in which method a drill rod assembly is inserted into a drill pipe while the drill pipe is locked to the drilling rig and the drill pipe is connected to the drill rod assembly in such a way that the rotational and impact energy received by the drill rod assembly from the drill hammer is transferable to the drill pipe. Next, a drill bit attached to the drill rod assembly and a ring bit attached to the drill pipe and the drilling rig are lowered to the sea bottom, the locking between the drill pipe and the drilling rig is opened and the drill hammer is switched on in order to begin the drilling by means of the drill bit installed to the bottom end of the drill rod assembly and the ring bit installed to the bottom end of the drill pipe. The drilling continues until the drill pipe reaches a predetermined depth into the sea bottom, after which the drill hammer is switched off, the drill pipe is locked to the drilling rig in such a way that the rotation and movement thereof in relation to the drilling rig is prevented, and the connection between the drill rod assembly and the drill pipe is released. The drill hammer is then switched on again and the drilling continues to the desired depth by means of the drill rod assembly and the drill bit.</p> |
