Abstract: A manufacturing method includes the steps of providing a mould containing a matrix material, providing an infiltrant material arranged so that, when molten, the infiltrant material will infiltrate into the matrix material, and heating the matrix material and the infiltrant material by induction heating using an induction heater. The induction heater includes a first coil and a second coil, wherein the first and second coils are energised independently of one another to allow increased control over the heating of different parts of the matrix material and infiltrant material within the mould.

Abstract: A vibration assembly of a drilling tool for drilling a wellbore penetrating a subterranean formation is disclosed. The downhole drilling tool includes a drill string, a bottomhole assembly and a drill bit. The vibration assembly includes a housing (334a) operatively connectable to the bottomhole assembly, expanders (122) positionable in the housing and radially extendable and retractable thereabout, and a radial vibrator (comprising mandrel (446), enlarger spring (48), cam portion (458) and vibration spring (570) operatively connectable to the expanders to vibrationally move the expanders against the wall of the wellbore whereby movement of the downhole tool is altered during drilling.

Abstract: A downhole tool and associated methods. The downhole tool includes a body with a throughbore; at least one extendable cutting member; and an actuation member. The actuation member is operatively associated with the extendable cutting member and movable relative to the body to extend the cutting member laterally from the body along an extension axis. The extension axis is offset from a radius of the body.

Abstract: A method of running a bore-lining tubing string into a bore includes running a tubing string, typically a liner string, into a bore while agitating the string. The agitation may also take place while the tubing is being cemented in the bore. Pressure pulses may be applied to fluid in the bore, which fluid may be cement slurry.

Abstract: An under-reaming tool comprises a body and a plurality of extendable cutters mounted on the body. The under-reaming tool is configured to be cycled between a first configuration in which the cutters are retracted and a second configuration in which the cutters are movable between retracted and extended positions. The under-reaming tool is configured to prevent extension of the cutters by an external fluid in the first and/or second configuration/s.

Abstract: An apparatus for use in controlling first and second downhole tools includes a first cyclical indexing mechanism associated with a first downhole tool, and a second cyclical indexing mechanism associated with a second downhole tool, wherein the first indexing mechanism defines at least three sequential indexing positions within a cycle and the second indexing mechanism defines at least two sequential indexing positions within a cycle. The apparatus includes at least one actuator for actuating the first and second indexing mechanisms in response to a common stimulus to cause said first and second indexing mechanisms to advance between respective indexing positions so as to permit co-ordination of the operational states of the associated first and second downhole tools. The apparatus may be used for controlling first and second under reamers or for controlling an under reamer and a corresponding stabilizer.

Abstract: A stabilizer, drill bit, or other component of a bottom hole assembly for use in drilling a borehole includes an elongate and generally cylindrical body, a flow bore in the body, a plurality of outwardly-extending blades, with a valley disposed between adjacent blades. A ring segment that is spaced from the body and extends across at least one valley to define a flow passage through which cuttings-laden drilling mud is conveyed with an upwardly-direct trajectory. The body includes a hole or passageway for conveying drilling mud from the flow bore to between the blades. The passageway terminates in an exit directed toward the flow passage so as to provide fresh drilling mud with a trajectory such that the fluid passes through the flow passage.

Abstract: A downhole tool including a fluid-actuated piston and a motor-driven valve. The fluid-actuated piston is operatively associated with a reciprocating mass. The motor-driven valve is configured to supply actuating fluid sequentially to drive the piston downwards and upwards. A method of reciprocating a mass in a downhole tool. The method including cycling a motor-driven valve between a first configuration and a second configuration. In the first configuration actuating fluid pressure drives a piston associated with the mass downwards. In the second configuration actuating fluid pressure drives the piston upwards.

Abstract: A resettable downhole tool actuator comprises a housing, a collet slidable within the housing and defining a seating with which a ball is engageable, in use, the collet being mounted upon a moveable support including a piston and arranged such that, when the bail engages the seating, fluid flow through an axially extending passage provided in the support is restricted, the housing including an increased diameter region arranged such that, when the seating is aligned with the increased diameter region, outward deflection of the collet permits the ball to pass through the seating and through the axially extending passage.

Abstract: A cutting element comprises a primary cutter including a first table of a hard material bonded to a first substrate of less hard form, the first substrate of the primary cutter having a recess formed therein in which a secondary cutter is located, the secondary cutter comprising a second table of a hard material bonded to a second substrate of less hard material, the first and second tables being spaced apart from one another by at least part of the first substrate.

Abstract: A cutting element comprises a table of superhard material bonded to a substrate, wherein the table defines a cutting edge and has a chamfered peripheral edge, and a groove in a sidewall of the cutting element passes through the chamfered peripheral edge, so as to reduce the depth of the chamfer at the location of the groove.

Abstract: A drill bit (10), for example of a fixed cutter type, comprises at least one structure, for example a blade, having first and second rows of cutters (35a-h) thereon. The first row is configured to achieve suitable performance when the drill bit drills in concentric mode. The second row of cutters is configured to improve the performance of the first row of cutters when the drill bit drills in eccentric mode. For example, the second row increases depth of cut and wear resistance in eccentric mode drilling. The drill bit may be mounted on a bent motor (120) used in directional drilling.

Abstract: A drill bit comprises at least one blade, comprising a plurality of cutting elements in the form of polycrystalline diamond cutters disposed on a leading edge of the blade, at least one diamond impregnated cutting region, disposed behind the leading edge of the blade, and wherein at least one of the cutters disposed on the leading, edge is an off-tip cutting element, arranged so that it does not engage with the formation during drilling until bit wear has taken place.

Abstract: A downhole apparatus includes a pressure pulse generator and a pulse reflector. The pulse reflector reflects at least a portion of an incident pressure pulse from the generator as a reflected pressure pulse. The apparatus is configured to provide the reflected pressure pulse with a phase shift with respect to the incident pressure pulse. A method of transmitting pressure pulses downhole includes generating a pressure pulse and reflecting at least a portion of an incident pressure pulse at a pulse reflector as a reflected pressure pulse. A phase shift of the reflected pressure pulse with respect to the incident pressure pulse is controlled.

Abstract: A downhole tool comprises a body, an extendable cutting member operable to cooperate with a hydraulically actuated cam member, and a cam member lock. The lock is configurable to be activated downhole to restrict movement of the cam member relative to the body and prevent extension of the cutting member.

Abstract: An under-reamer includes a body and extendable cutters mounted on the body. The under-reamer is configured to be cycled between a first configuration in which the cutters are retracted and a second configuration in which the cutters are movable between retracted and extended positions. A control mechanism is provided and is configurable to prevent the under-reamer cycling between the first and second configurations and thus maintains the under-reamer in a selected one of the first and second configurations.

Abstract: An apparatus for separating a hydrocarbon content from a material matrix composes the hydrocarbon content and a water content, the apparatus comprising: a material feeder arranged to feed material through a treatment chamber, the treatment chamber comprising a window which is substantially transparent to microwaves; a microwave emitter arranged in use to expose feed material in the treatment chamber to microwaves via the window in order to cause rapid heating of at least part of the water content of the matrix to form steam, so as to remove at least part of the hydrocarbon content from the matrix; wherein the material feeder and treatment chamber are arranged so that in use, the treatment chamber is substantially tilted with material/matrix.

Abstract: A resettable downhole tool actuator comprises a housing, a collet slidable within the housing and defining a seating with which a ball is engageable, in use, the collet being mounted upon a moveable support including a piston and arranged such that, when the bail engages the seating, fluid flow through an axially extending passage provided in the support is restricted, the housing including an increased diameter region arranged such that, when the seating is aligned with the increased diameter region, outward deflection of the collet permits the ball to pass through the seating and through the axially extending passage.

Abstract: A method of operating a downhole tool in a no-flow configuration in which a piston and a flow-restriction cooperate to occlude a tool throughbore. The tool is reconfigured to an intermediate configuration by flowing fluid through the tool at an intermediate flow-rate lower than an operating flow-rate and axially translating the piston to an intermediate position in which the piston and flow-restriction cooperate to define an intermediate flow area. Axial translation of the piston between a no-flow position and the intermediate position includes an occlusional stage of a first axial extent during which the piston and the flow-restriction occlude the tool throughbore, and a transitional stage of a second axial extent during which the piston and the flow-restriction cooperate to provide a step-change in flow area. The tool is reconfigured to an operating configuration by flowing fluid through the tool at the operating flow-rate and axially translating the piston.

Abstract: A downhole tool and associated methods. The downhole tool includes a body with a throughbore; at least one extendable cutting member; and an actuation member. The actuation member is operatively associated with the extendable cutting member and movable relative to the body to extend the cutting member laterally from the body along an extension axis. The extension axis is offset from a radius of the body.