DEVICE FOR GUIDING A DRILLING TOOL INTO A WELL AND FOR EXERTING THEREON A HYDRAULIC FORCE

摘要

The device is interleaved in a string of drilling pipes and is provided with a drilling tool at its lower end. It is comprised of a tubular body (1) and of an outer sleeve (3) rotating about the body and longitudinally displaceable with respect to said body. Radially displaceable pistons (16), in an extension position, come into anchoring engagement in the wall of the well and immobilize the external sleeve (3). A jack (32) is used to displace the body and the drilling tool integral therewith, with respect to the external sleeve and to exert thereby a pushing force onto the tool. A control assembly may without operator, control the execution of a series of successive cycles of anchoring of the external sleeve in the well and of displacement of the drilling tool with respect to the external sleeve. The present invention may be applied to the drilling of oil wells.