Camco Drilling Group Limited

Nl Petroleum Products Limited

Nl Industries

Reed Tool Company

Camco International (uk) Limited

Camco Drilling Group Limited of Hycalog

Other

Camco Drilling Group Ltd. of Hycalog

John M Fuller

Malcolm Roy Taylor

John D Barr

Nigel Dennis Griffin

Andrew D Murdock

Alex Newton

Terry R Matthias

Steven Taylor

Joseph A Gasan

Michael C Regan

Daniel J Sarik

A cutting structure for a rotary drag-type drill bit includes a cutting element mounted on a member on the bit body, which may be a carrier secured to the bit body or part of the bit body itself. The surface of the member on which the cutting element is mounted is formed with a groove, adjacent the cutting element. The downstream end of the groove is located near a nozzle in the bit body through which a jet of drilling fluid emerges, so that the groove directs to the front of the cutting element the flow of drilling fluid which impinges on the groove. An array of separate grooves may lead from the nozzle to different cutting elements. The flow of drilling fluid directed towards each cutting element serves to break up cuttings removed from the formation by the cutting element and to carry the cuttings away from the element.

Cutting structure for rotary drill bits

Formation engaging elements are moveably mounted onto a drill bit. Such elements may be used to protect other rigidly mounted formation engaging elements from impacts that occur during use of the drill bit, or they may be used to alter the aggressiveness of the drill bit when used in directional drilling operations.

Rotary drill bit having moveable formation-engaging members

A cutting structure for a rotary drag-type drill bit includes a preform cutting element mounted on a carrier which, in use, is mounted on the drill bit and comprises a front facing table of superhard material bonded to a less hard substrate. A portion of the carrier on which the preform cutting element is mounted is shaped, adjacent the cutting element, for engagement by a chip of formation material being removed by the cutting element from the formation being drilled so as to tend to break the chip away from the surface of the formation. A portion of the carrier, or a portion of the bit body itself, may also be shaped, adjacent the cutting element, to direct to a location in front of the cutting element a flow of drilling fluid which impinges on said surface so as to assist in chip removal.

Cutting structures for rotary drill bits

A drilling assembly for drilling holes in subsurface formations comprises a drill bit 10, a drive unit 12 including a housing and a rotor 11 operatively coupled to the drill bit to rotate the drill bit relative to the housing, and a modulated bias unit 14 coupled to rotate with the drive unit housing and apply a lateral bias thereto in synchronism with rotation of the housing. The modulated bias unit 14 comprises one or more hydraulic actuators including members 16 which, in use, bear against the sides of the borehole, and means for modulating the pressure of fluid supplied to the actuators in synchronism with rotation of a component of the drilling assembly, and in selected angular phase relation thereto, whereby each hydraulic actuator is actuated in a selected rotational position of the component.

Drilling assembly for drilling holes in subsurface formations

A cutter assembly for a rotary drag-type drill bit includes a preform cutting element comprising a front facing table of polycrystalline diamond bonded to a tungsten carbide substrate, the cutting element being mounted on a tungsten carbide carrier which is received in a socket in the body of the drill bit. The carrier comprises a sector-shaped portion of a disc, and the cutting element is bonded to one of the straight edge surfaces of the carrier, adjacent the apex of the sector shape. The side surfaces of the carrier taper inwardly, as viewed in cross-section, as they extend towards the curved edge surface of the carrier.

Cutter assemblies for rotary drill bits

A rotary drill bit comprises a bit body, a shank for connection to a drill string, a plurality of cutters mounted on the bit body, and a gauge structure which extends around the bit body and, in use, engages the surrounding formation forming the sides of the borehole being drilled. At least a section of the gauge structure is rotatably mounted on the bit body so that, in use, the gauge section may remain substantially non-rotating in engagement with the formation while the bit body rotates relative to it. The external surface of the non-rotating gauge section may be formed with longitudinal grooves to permit the flow of drilling fluid past the gauge section to the annulus. Alternatively the outer surface of the gauge section may be generally cylindrical, in which case internal passages are provided through the gauge section, and/or the bit body, for the flow of drilling fluid past the gauge section to the annulus.

Rotary drill bit having a non-rotating gauge section

A preform cutting element for a drag-type rotary drill bit includes a facing table of polycrystalline diamond bonded to a less hard substrate, such as cemented tungsten carbide. The element is formed by first forming a solid substrate, and then applying an electron beam, laser, or other intense heating source to adjacent areas of the front surface of the substrate to melt the surface and form an array of holes or holes therein. A layer of polycrystalline diamond particles is applied to the substrate so that such particles fill the holes or holes, and the diamond layer and substrate are then subjected to pressure and temperature in a high pressure, high temperature press to bond the superhard layer to the substrate. The engagement of parts of the diamond table in the holes or holes in the substrate provides a mechanical interlock to improve the strength of the bond between the table and substrate.

Elements faced with superhard material

A rotary drill bit for drilling holes in subsurface formations comprises a bit body having a shank for connection to a drill string, a number of circumferentially spaced blades on the bit body each extending outwardly away from the central axis of rotation of the bit, a number of cutters mounted side-by-side along each blade, and a passage in the bit body for supplying drilling fluid to the surface of the bit for cleaning and cooling the cutters. The blades comprise alternating primary and secondary blades. The cutters on the primary blades are primary cutters which are located at different radial distances from the bit axis so as to define a cutting profile which, in use, covers substantially the whole of the bottom of the bore hole being drilled. At least the majority of the cutters on the secondary blades are secondary cutters each of which is located at substantially the same radial distance from the bit axis as an associated primary cutter on the preceding primary blade.

Rotary drill bits

A rotary drill bit comprises a bit body having a shank for connection to a drill string, a plurality of cutters mounted on the bit body, each cutter having a cutting face, and means for supplying drilling fluid to the surface of the bit body to cool and clean the cutters. At least some of the cutters are lateral cutters located to act sideways on the formation being drilled, and the cutting faces of such lateral cutters are orientated to exhibit negative side rake and negative top rake with respect to the surface of the formation. The negative side rake angle is greater than 20.degree. and may be as much as 90.degree., and the negative top rake angle is also more than 20.degree.. A single cutter may include two cutting faces at different negative side rake angles, e.g. the cutter may comprise a generally cylindrical substrate formed at one end with two oppositely inclined surfaces meeting along a ridge, a facing table of polycrystalline diamond being bonded to the substrate surfaces and extending over the ridge.

A preform cutting element, for use on a rotary drill bit, includes a facing table of polycrystalline diamond bonded to a tungsten carbide substrate, a cutting edge being formed by part of the peripheral surface of the facing table. The rear surface of the facing table is integrally formed with a plurality of spaced elongate ribs which project into the substrate, at least the majority of the ribs being located in the vicinity of the cutting edge. The ribs may intersect the cutting edge and extend only part way across the facing table from the cutting edge. The ribs may vary in width and/or depth.

A preform element, such as a cutting element for a drag-type drill bit, includes a facing table of superhard material having a front face, a peripheral surface, and a rear surface bonded to a substrate which is less hard than the superhard material. The rear surface of the facing table is integrally formed with a plurality of ribs which project into the substrate and extend in directions outwardly away from an inner area of the facing table towards the peripheral surface thereof.

A rotary drill bit for use in drilling holes in subsurface earth formations comprises a bit body having a shank at one end for connection to a drill string and an operating end face at the other end. A plurality of first cutting structures, each comprising a preform cutting element, is mounted in the bit body at the end face thereof, and each has a superhard front cutting face. The bit body includes a plurality of protuberances projecting outwardly from the adjacent portions of the end face, the protuberances forming a plurality of second cutting structures disposed in generally trailing relation, respectively, to at least some of the first cutting structures. Each of the protuberances is impregnated with superhard particles through a significant depth measured from the outermost extremity of the protuberance. At least a major operative portion of each of the second cutting structures is circumferencially separated from the respective leading first cutting structure by an open space, and is likewise radially separatred from the nearest adjacent second cutting structure or structures.

Rotary drill bit for use in drilling holes in subsurface earth formations

A rotary drill bit for use in drilling or coring holes in subsurface formations comprises a bit body having a shank for connection to a drill string, a plurality of cutting structures mounted at the surface of the bit body, and a passage in the bit body for supplying drilling fluid to the surface of the bit body for cooling and/or cleaning the cutting structures. The bit body is formed from steel, and each cutting structure comprises a cutting element, in the form of a unitary layer of thermally stable polycrystalline diamond material, brazed to a carrier received in a socket in the steel body of the bit.

Cutting structures for steel bodied rotary drill bits

A rotary drill bit for use in drilling holes in subsurface earth formations comprises a bit body having a shank at one end for connection to a drill string and an operating end face at the other end. A plurality of first cutting structures, each comprising a preform cutting element, is mounted in the bit body at the end face thereof, and each has a superhard front cutting face. The bit body includes a plurality of protuberances projecting outwardly from the adjacent portions of the end face, the protuberances forming a plurality of second cutting structures disposed in generally trailing relation, respectively, to at least some of the first cutting structures. Each of the protuberances is impregnated with superhard particles through a significant depth measured from the outermost extremity of the protuberance. At least a major operative portion of each of the second cutting structures is circumferencially separated from the respective leading first cutting structure by an open space, and is likewise radially separated from the nearest adjacent second cutting structure or structures.

A rotary drill bit for use in drilling or coring deep holes in subsurface formations comprises a bit body having a shank for connection to a drill string and a plurality of cutting elements mounted at the surface of the bit body. Each cutting element is bonded to a stud which is received in a socket in the bit body. Spaced rearwardly of each cutting element is a separate abrasion element comprising a stud which is received in a socket in the bit body and is impregnated with particles of natural or synthetic diamond. The abrasion element provides a back-up in the event of failure or excessive wear of the cutting element and its spacing from the cutting element prevents the damaging transfer of heat from the abrasion element to the cutting element. The cooling may be enhanced by providing a channel for drilling fluid between the cutting element and abrasion element.

Growing community of inventors

Nailsworth, United Kingdom

John M Fuller