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

FIELD: drilling equipment, particularly special apparatus for deflecting the boring, for example special drill bits, knuckle joints, whipstocks.

SUBSTANCE: hydraulic whipstock comprises diverting wedge having inclined working surface made as gutter and support unit having cylindrical hollow body with orifices for slip receiving and spacing member inserted in the hollow body and having inclined surfaces. Slips having teeth on face surfaces and depressions in rear slip surfaces are slideably arranged on the inclined surfaces. The depression mates T-shaped extension made on inclined spacing member surface. Device also has hydraulic chamber and flexible high-pressure hose to supply liquid to hydraulic chamber. Hydraulic whipstock comprises sub and packers located between diverting wedge and cylindrical hollow support unit body. Spacing member comprises guiding section having piston-like lower part and passing into spacing section made as regular truncated trihedral prism tapering downwards. Prism ribs are defined by inclined surfaces and have extensions to receive slips with teeth inclined downwards. Slips are radially arranged in windows made in lower part of cylindrical hollow support unit body and shifted 120° one relatively another. Annular groove and thrust are created in upper part of support unit body. The annular groove and thrust define hydraulic chamber along with cylindrical surface of guiding part created in spacing member. Hydraulic chamber is connected with flexible hose through cavities formed in sub and guiding part of spacing member correspondingly. The last cavity is connected to hydraulic chamber through distribution means made as three through orifices forming 120° angle with each other. Support unit body may slide along guiding part of spacing member along with simultaneous hydraulic chamber volume change. Cap is put on cylindrical hollow support unit body end so that the cap is threadedly secured to spacing section of spacing member. Sealing means are installed between inner surface of hollow cylindrical support unit body and outer surface of spacing member.

EFFECT: increased reliability of whipstock connection to casing pipe walls and simplified whipstock removal.

5 dwg