CONTROLLABLE WHIPSTOCK Russian patent published in 2007 - IPC E21B7/08 

FIELD: well drilling equipment, particularly whipstocks with changeable angles used in horizontal and inclined well drilling.

SUBSTANCE: controllable whipstock comprises hydraulic cylinder with throttle and piston-shaft assembly provided with guiding extensions, deflectable unit with grooves to receive guiding extensions of piston-shaft assembly, return springs and bearing. Hydraulic cylinder additionally has upper and lower immovable fixing bushes with cams uniformly distributed over diameter and shifted one towards another in radial direction. Hydraulic cylinder comprises spring-loaded movable fixing bush provided with two rows of cams uniformly distributed over diameter thereof. Lower immovable fixing bush and spring-loaded movable one are provided with groves to receive guiding extensions of piston-shaft assembly.

EFFECT: increased operational reliability due to elimination of load necessary for whipstock rotation.

3 dwg