Abstract: This invention relates to a steering assembly and to a steering component, suitable for use in drilling operations for oil and gas. The steering assembly comprises a downhole motor which can rotate the drill bit, and a steering component. The steering component has a shaft and a set of elements for engaging the borehole in use. The shaft has a longitudinal axis. The set of elements has a centerline and is movable relative to the shaft between a first position in which the centerline is offset from the longitudinal axis of the shaft by a first distance, and a second position in which the centerline is offset from the longitudinal axis of the shaft by a second distance. In use in drilling operations, movement of the set of elements from the first position to the second position alters the degree of curvature of the drilled hole.

Abstract: This invention relates to a steerable drill bit arrangement, in particular for the use in drilling boreholes for oil and gas extraction. There is provided a steerable drill bit arrangement in which the drill bit is connected to a drill string including a steering component and a stabiliser, the stabiliser being located between the steering component and the drill bit, the steering component being adapted to move the drill string transversely relative to a borehole in which it is located, the stabiliser having an inner part adapted to rotate with the drill string and an outer part adapted to engage the borehole wall, the outer part being rotatable relative to the inner part so that the outer part can remain substantially stationary as the remainder of the stabiliser rotates with the drill string.

Abstract: This invention relates to a steerable drill bit arrangement, in particular for the use in drilling boreholes for oil and gas extraction. There is provided a steerable drill bit arrangement in which the drill bit (20) is connected to a drill string (16) including a steering component (12) and a stabiliser (14), the stabiliser (14) being located between the steering component (12) and the drill bit (20), the steering component (12) being adapted to move the drill string (16) transversely relative to a borehole in which it is located, the stabiliser (14) having an inner part (32) adapted to rotate with the drill string (16) and an outer part (34) adapted to engage the borehole wall, the outer part (34) being rotatable relative to the inner part so that the outer part (34) can remain substantially stationary as the remainder of the stabiliser (14) rotates with the drill string (16).

Abstract: A method for manufacturing NMR measurement-while-drilling tool having the mechanical strength and measurement sensitivity to perform NMR measurements of an earth formation while drilling a borehole, and a method and apparatus for monitoring the motion of the measuring tool in order to take this motion into account when processing NMR signals from the borehole. The tool has a permanent magnet with a magnetic field direction substantially perpendicular to the axis of the borehole, a steel collar of a non-magnetic material surrounding the magnet, antenna positioned outside the collar, and a soft magnetic material positioned in a predetermined relationship with the collar and the magnet that helps to shape the magnetic field of the tool. Due to the non-magnetic collar, the tool can withstand the extreme conditions in the borehole environment while the borehole is being drilled.

Abstract: A method for manufacturing NMR measurement-while-drilling tool having the mechanical strength and measurement sensitivity to perform NMR measurements of an earth formation while drilling a borehole, and a method and apparatus for monitoring the motion of the measuring tool in order to take this motion into account when processing NMR signals from the borehole. The tool has a permanent magnet with a magnetic field direction substantially perpendicular to the axis of the borehole, a steel collar of a non-magnetic material surrounding the magnet, antenna positioned outside the collar, and a soft magnetic material positioned in a predetermined relationship with the collar and the magnet that helps to shape the magnetic field of the tool. Due to the non-magnetic collar, the tool can withstand the extreme conditions in the borehole environment while the borehole is being drilled.

Abstract: A drilling tool has a bent sub or a defined “High Side”. An instrument housing which includes a magnetometer is secured to the directional drilling tool. The magnetometer measures the magnetic field vector in the plane perpendicular to the tool axis. Prior to running the directional drilling tool and the instrument housing into the well, a magnetic source is positioned next to the instrument housing at a position near the magnetometer. The magnetic source is made and positioned such that its magnetic field at the magnetometer points to the chalk line of the high side of a bent sub. The net magnetic field generated from the source is obtained by the difference in magnetic field measurements before and while the magnetic source is applied The azimuthal angle between the net magnetic field vector and the x-axis of the magnetometer or other direction sensor reference point used for tool face calculation is obtained by a computer.

Abstract: A method for manufacturing NMR measurement-while-drilling tool having the mechanical strength and measurement sensitivity to perform NMR measurements of an earth formation while drilling a borehole, and a method and apparatus for monitoring the motion of the measuring tool in order to take this motion into account when processing NMR signals from the borehole. The tool has a permanent magnet with a magnetic field direction substantially perpendicular to the axis of the borehole, a steel collar of a non-magnetic material surrounding the magnet, antenna positioned outside the collar, and a soft magnetic material positioned in a predetermined relationship with the collar and the magnet that helps to shape the magnetic field of the tool. Due to the non-magnetic collar, the tool can withstand the extreme conditions in the borehole environment while the borehole is being drilled.

Abstract: A drilling tool has a bent sub or a defined “High Side”. An instrument housing which includes a magnetometer is secured to the directional drilling tool. The magnetometer measures the magnetic field vector in the plane perpendicular to the tool axis. Prior to running the directional drilling tool and the instrument housing into the well, a magnetic source is positioned next to the instrument housing at a position near the magnetometer. The magnetic source is made and positioned such that its magnetic field at the magnetometer points to the chalk line of the high side of a bent sub. The net magnetic field generated from the source is obtained by the difference in magnetic field measurements before and while the magnetic source is applied The azimuthal angle between the net magnetic field vector and the x-axis of the magnetometer or other direction sensor reference point used for tool face calculation is obtained by a computer.

Abstract: A method for manufacturing NMR measurement-while-drilling tool having the mechanical strength and measurement sensitivity to perform NMR measurements of an earth formation while drilling a borehole, and a method and apparatus for monitoring the motion of the measuring tool in order to take this motion into account when processing NMR signals from the borehole. The tool has a permanent magnet with a magnetic field direction substantially perpendicular to the axis of the borehole, a steel collar of a non-magnetic material surrounding the magnet, antenna positioned outside the collar, and a soft magnetic material positioned in a predetermined relationship with the collar and the magnet that helps to shape the magnetic field of the tool. Due to the non-magnetic collar, the tool can withstand the extreme conditions in the borehole environment while the borehole is being drilled.

Abstract: An NMR measurement-while-drilling tool having the mechanical strength and measurement sensitivity to perform NMR measurements of an earth formation while drilling a borehole, and a method and apparatus for monitoring the motion of the measuring tool in order to take this motion into account when processing NMR signals from the borehole. The tool has a permanent magnet with a magnetic field direction substantially perpendicular to the axis of the borehole, a steel collar of a non-magnetic material surrounding the magnet, antenna positioned outside the collar, and a soft magnetic material positioned in a predetermined relationship with the collar and the magnet that helps to shape the magnetic field of the tool. Due to the non-magnetic collar, the tool can withstand the extreme conditions in the borehole environment while the borehole is being drilled.

Abstract: A downhole steering tool will steer the angle of the drill bit for drilling directional wells. The steering tool includes a steering housing which is mounted on the drill string above the drill bit. The steering housing can be held against rotation while the drill string rotates to cause the bit to drill in a desired direction. Guide members are mounted on the steering housing. The guide members may engage the borehole. The guide members can be turned about an axis which is perpendicular to the longitudinal axis of the steering housing. Turning the guide members causes the steering housing to rotate relative to the borehole in one direction or the other as the housing slides downward in the borehole. Reorienting the steering housing allows steering of the drill bit.

Abstract: An NMR measurement-while-drilling tool having the mechanical strength and measurement sensitivity to perform NMR measurements of an earth formation while drilling a borehole, and a method and apparatus for monitoring the motion of the measuring tool in order to take this motion into account when processing NMR signals from the borehole. The tool has a permanent magnet with a magnetic field direction substantially perpendicular to the axis of the borehole, a steel collar of a non-magnetic material surrounding the magnet, antenna positioned outside the collar, and a soft magnetic material positioned in a predetermined relationship with the collar and the magnet that helps to shape the magnetic field of the tool. Due to the non-magnetic collar, the tool can withstand the extreme conditions in the borehole environment while the borehole is being drilled.

Abstract: An NMR measurement-while-drilling tool having the mechanical strength and measurement sensitivity to perform NMR measurements of an earth formation while drilling a borehole, and a method and apparatus for monitoring the motion of the measuring tool in order to take this motion into account when processing NMR signals from the borehole. The tool has a permanent magnet with a magnetic field direction substantially perpendicular to the axis of the borehole, a steel collar of a non-magnetic material surrounding the magnet, antenna positioned outside the collar, and a soft magnetic material positioned in a predetermined relationship with the collar and the magnet that helps to shape the magnetic field of the tool. Due to the non-magnetic collar, the tool can withstand the extreme conditions in the borehole environment while the borehole is being drilled.

Abstract: A mud pulse telemetry system for imparting data pulses to drilling fluids circulating in a drill string including an improved valve arrangement for modulating the pressure of the circulating drilling fluid is disclosed. A shear-type valve is arranged in a through conduit configuration so that the seat face of the valve is covered when the valve is in an open position, thus preventing impingement of abrasive fluid particles on the valve seat face during the open flow position of the valve. The activation means is connected to the valve gate through a floating connection which prevents lateral stress forces operating on the valve from being imparted to the solenoid. The floating connection also permits convenient removal of the valve seat and gate from an access opening on the exterior of the drill string housing to facilitate the replacement of critical valve parts without removing the valve subassembly from the drill string.

Abstract: A mud pulse telemetry system for imparting data pulses to drilling fluids circulating in a drill string including an improved valve arrangment for modulating the pressure of the circulating drilling fluid is disclosed. A rotary acting shear-type valve is arranged in a through conduit configuration so that the seat face of the valve is covered when the valve is in an open position, thus preventing impingement of abrasive fluid particles on the valve seat face during the open flow position of the valve. The rotatable gate is positively driven through an arc in opposite directions by rotary solenoids so that a gate aperture is moved into and out of axial alignment with the opening in the valve seat to generate the pressure pulse. The rotary solenoid valve also permits a tailoring of the force curve of the solenoid for maximum power in actuation of larger flow orifices. The larger flow orifice permits generation of pressure pulses of increased amplitude.

Abstract: A latch device for controlling a valve in a mud pulse telemetry system for imparting data pulses to drilling fluids circulating in a drill string is disclosed. A latch device and valve arrangement including an improved shear type, solenoid operated valve for modulating the pressure of the circulating drilling fluid is disclosed. A latching solenoid armature is connected to the valve gate through separate open and close solenoids having their armatures operatively connected to act as a single unit. The single unit armature is normally restrained from movement by the solenoid deactivated latch device. The latch device is arranged so that the vibrational and impact loads on the drill string serve to further maintain the modulating valve in a closed position.