Abstract: The present invention relates to a downhole tool (102) for selectively opening and closing a lateral borehole extending from a primary borehole. The tool (102) comprises a body (104) incorporating a wall provided with an opening (116) extending therethrough; a deflector member (106) slidably mounted in the body (104) and having a deflecting surface (126) for deflecting, in use, downhole equipment laterally within the body (104). The deflector member (106) is slidable between an open position, in which the deflecting surface is located adjacent and facing towards said opening so that, in use, downhole equipment laterally deflected by the deflecting surface is directed through said opening, and a closed position, in which the deflecting surface is oriented relative to said opening so as to prevent downhole equipment from being laterally deflected through said opening during use. In either position, equipment may pass into the primary borehole downhole of the primary/lateral junction.

Abstract: A downhole apparatus which can be used as multi-cycle circulating subs utilized in downhole drilling operations, includes a piston (242) slidably mounted in a body between positions in which at least one aperture in the body is opened and closed. Movement of the piston (242) is controlled by a pin (86), secured to one of the body and a control member, and a control groove (52) formed in the other of the body and control member for receiving a portion of the pin. An arrangement of elements (232, 276) respectively connected to the control member and body is such as to normally resist axial movement of the control member from a first axial position to a second axial position. A spring (44) is located in a chamber for biasing the piston (242). The chamber is vented by an opening in the body.

Abstract: The present invention relates to downhole apparatus for limiting rotation of a rotor (4) relative to a stator (8) associated with said rotor (4). Apparatus according to the invention is provided with a locking member (12) movable from a first axial position to a second axial position by the application of a static fluid pressure to a differential area of said locking member (12). The apparatus is characterised by means for selectively applying static fluid pressure to said differential area of said locking member (12).

Abstract: Bypass valve for use in wellbores, particularly during the setting of hydraulic anchor packers, a bypass valve is provided with a body (4) incorporating a wall provided with at least one opening (20) and a piston (30) slidably mounted and having a longitudinal bore extending therethrough. The piston (30) is movable between a first position, in which the bore of the piston (30) is substantially isolated from the exterior of the body (4), and a second position in which a passage is provided from the bore of the piston (30) to the exterior of the body (4). Constraining means (42, 52) prevent movement of the piston (30) from the first to the second position. Overriding means are provided to permit movement to the second position.

Abstract: Bypass valve for use in wellbores, particularly during the setting of hydraulic anchor packers, a bypass valve is provided with a body (4) incorporating a wall provided with at least one opening (20) and a piston (30) slidably mounted and having a longitudinal bore extending therethrough. The piston (30) is movable between a first position, in which the bore of the piston (30) is substantially isolated from the exterior of the body (4), and a second position in which a passage is provided from the bore of the piston (30) to the exterior of the body (4). Constraining means (42, 52) prevent movement of the piston (30) from the first to the second position. Overriding means are provided to permit movement to the second position.