Hydrostatic rotary drive for deep boring - has hydraulic motor and removable hydraulic supply line in casing string

摘要

Hydrostatic rotary drive, incorporated for deep boring, has a hydraulic motor, pref. of the multi-stage axial-piston type, and a removable hydraulic supply line (1) in the casing string (4). The torque is transmitted from the motor (2) to the cutting tool (7) via a sliding carrier (6) connected to the drill string (5). Several variants are claimed for the hydraulic and other arrangements, and an electric cable for data transmission can be incorporated. 69 USE/ADVANTAGE - Improved advance of the drill is provided for deep and very deep boring by having, in addition to the rotary table, a removable hydraulic drive. For example, for a 5000-m boring the proposed rotary drive can be used at 2000 m to enable the 5000 m to be, in effect, reduced to 3000 m and the urilling advance thus considerably increased.