Drilling device with controlled trajectory

摘要

The drilling device comprises at least one stabiliser 7 consisting of a tubular body 10 in which bearing blades 18 are mounted so as to move radially and controlled by a piston 25. The piston 25 has radially sloping inclines 40, 41 placed one after the other around the piston 25 and complementary parts for ensuring the rotation and the return of the piston 25, forming, around the piston 25, a continuous actuating surface. The piston is moved in one direction by the drilling fluid and in the other by a spring 31. The end of each of the movement steps by the drilling fluid is accompanied with a head loss which is greatly increased in the drilling fluid.