RETRIEVABLE WHIPSTOCK Russian patent published in 2006 - IPC E21B7/08 

FIELD: drilling equipment, particularly adapted to cut openings in casing pipe with the use of wedge whipstock fastened to casing pipe wall.

SUBSTANCE: chamber body has cross-section, which varies from inner side thereof, namely the body has cylindrical upper surface and conical lower surface. Chamber body is retained in diverting body part of wedge whipstock with the use of bolts so that the body may be displaced in longitudinal direction with respect to the chamber body and is fixedly connected to shear bolts. Hydraulic distribution means is arranged in the chamber body. Hydraulic distribution means also has body with cross-section variable from outer surface thereof and is complementary to that of inner chamber body surface cross-section in contact area thereof. Hydraulic distributor body is threadedly fixed inside chamber body and is provided with central through orifice, U-shaped cavity defined in lower part thereof, mutually symmetric cavities formed in horizontal plane, as well as inlet and outlet valve housings retained in above cavities. The valves have spring-loaded balls. Inlet valve ball rests upon end surface of nipple arranged in valve housing and projecting out of chamber and whipstock bodies. Flexible hose is located on face wedge whipstock surface in diverting part thereof and is connected to supply metal pipe through nipples. Liquid supply metal pipe is laid in longitudinal groove formed in wedge whipstock surface from rear side thereof and is connected with inlet valve nipple. Spring-loaded ball of outlet valve rests upon conical cavity formed in inner wedge whipstock surface in thrust part thereof. Channels are formed in hydraulic distributor body so that the channels terminate at end surface and channel inlets are located in inlet and outlet valve housings. Space is defined under conical cavity of wedge whipstock. The whipstock is provided with molded T-shaped piston movably secured and retained in chamber body and in through central orifice of hydraulic distributor body by means of sealers. Lower piston end part is fixedly fastened to holder in U-shaped hydraulic distributor body cavity and is articulated to vertical lever. Vertical lever width is equal to two driving lever widths. Clamping member is made as die with teeth formed on face surface and with longitudinal groove created in rear side thereof. The die has orifices for hinged driving and driven lever connection.

EFFECT: optimized cooperation of whipstock members, increased maintainability and fastening ability, as well as improved operational reliability of the device.

6 dwg