Abstract: The invention relates to a device for determining the depth and orientation of a feature in a wellbore, and to a corresponding method. It also relates to a downhole apparatus for performing an operation in a well comprising a device for determining the depth and orientation of a feature in a wellbore and a device for performing the operation. In an embodiment, a downhole device (42) for determining the depth and orientation of a feature (24, 26, 28) in a wellbore (12) containing a ferrous tubing (14) is disclosed, the device comprising: at least one magnetic field sensor (44) for monitoring the inherent magnetic field of the ferrous tubing so that the presence of the feature can be detected; and at least one orientation sensor (48) for determining the orientation of the device within the wellbore.

Abstract: The invention relates to methods of determining whether a wellbore sealing operation has been performed correctly, and to wellbore-lining tubing which facilitates the determination of whether a wellbore sealing operation has been performed correctly. The invention has a utility in determining whether cement has been correctly supplied into an annular region defined between an internal wall of a wellbore and an external surface of a wellbore-lining tubing located in the wellbore, or whether a packer has been properly set to seal such an annular region.

Abstract: The invention relates to a wellbore-lining tubing comprising at least one window pre-formed in the wall of the tubing and a device for selectively generating a fluid pressure pulse, and to a method of forming a lateral wellbore employing such a tubing. In an embodiment, a wellbore-lining tubing (130m) is disclosed which comprises: a tubing wall (32m), an internal fluid flow passage (30m), and at least one window (154m) pre-formed in the wall of the tubing; a device (34m) for selectively generating a fluid pressure pulse, the device located at least partly in a space (36m) provided in the wall of the tubing; and a coupling (190) for receiving a deflection tool (192) so that the deflection tool can be secured to the tubing and employed to divert a downhole component (202) through the window in the tubing wall.

Abstract: A downhole tool for generating a fluid pressure pulse, and to a method of generating a fluid pressure pulse downhole. One example being an improved downhole tool and method for transmitting data signals from a downhole environment to surface, the downhole tool comprising a fluid actuated flow restrictor; a first fluid flow path for flow of actuating fluid to actuate the flow restrictor; a second fluid flow path for flow of actuating fluid to actuate the flow restrictor; and a control member movable between a first closed position where the first fluid flow path is closed and the second fluid flow path is open, and a discrete second closed position where the first fluid flow path is open and the second fluid flow path is closed, for controlling actuation of the flow restrictor to generate a fluid pressure pulse.

Abstract: A downhole tool for generating a fluid pressure pulse, and to a method of generating a fluid pressure pulse downhole. One example being, an improved downhole tool and method for transmitting data signals from a downhole environment to surface, the downhole tool comprising a fluid actuated flow restrictor; a first fluid flow path for flow of actuating fluid to actuate the flow restrictor; a second fluid flow path for flow of actuating fluid to actuate the flow restrictor; and a control member movable between a first closed position where the first fluid flow path is closed and the second fluid flow path is open, and a discrete second closed position where the first fluid flow path is open and the second fluid flow path is closed, for controlling actuation of the flow restrictor to generate a fluid pressure pulse.

Abstract: There is disclosed an electrically insulating device in the form of a sleeve (12) for a downhole tool, for electrically insulating a first threaded electrically conductive member in the form of an anchor sub (16) from a second threaded electrically conductive member in the form of an insulated sub (18). An assembly (10) including the sleeve (12) has particular use in measurement while drilling (MWD)/logging while drilling (LWD) procedures. In one embodiment, a third member in the form of a threaded electrically conductive sleeve sub (20) is coupled to the insulated sub by a second sleeve (14), to create an insulated gap between the anchor and sleeve subs (16, 20).

Abstract: The invention relates to a downhole tool for generating a fluid pressure pulse, and to a method of generating a fluid pressure pulse downhole. In one embodiment of the invention, an improved downhole tool (10) and method for transmitting data signals from a downhole environment to surface is disclosed, the downhole tool (10) comprising a fluid actuated flow restrictor (22); a first fluid flow path (23) for flow of actuating fluid to actuate the flow restrictor (22); a second fluid flow path (25) for flow of actuating fluid to actuate the flow restrictor (22); and a control member (12) movable between a first closed position where the first fluid flow path (23) is closed and the second fluid flow path (25) is open, and a discrete second closed position where the first fluid flow path (23) is open and the second fluid flow path (25) is closed, for controlling actuation of the flow restrictor (22) to generate a fluid pressure pulse.

Abstract: There is disclosed an electrically insulating device in the form of a sleeve (12) for a downhole tool, for electrically insulating a first threaded electrically conductive member in the form of an anchor sub (16) from a second threaded electrically conductive member in the form of an insulated sub (18).