Camco International (uk) Limited

Camco International, Inc.

Steven Taylor

Malcolm Roy Taylor

Douglas Bruce Caraway

Tom Scott Roberts

Graham R Watson

John Hayward

Andrew D Murdock

John M Fuller

John M Clegg

Alex Newton

Nigel Dennis Griffin

Dean Travers Watson

Michael Tomczak

Alex Nexton

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 rotary drill bit for use in drilling holes in subsurface formations comprises a bit body having a leading face and a gauge region, a number of blades formed on the leading face of the bit and extending outwardly away from the axis of the bit so as to define between the blades a number of fluid channels leading towards the gauge region, a number of cutting elements mounted side-by-side along each blade, and a number of nozzles in the bit body for supplying drilling fluid to the fluid channels for cleaning and cooling the cutting elements. In each of the fluid channels, adjacent the gauge region, is an opening into an enclosed passage which passes internally through the bit body to an outlet which, in use, communicates with the annulus between the drill string and the wall of the borehole being drilled. The gauge region of the drill bit comprises a substantially continuous bearing surface which extends around the whole of the gauge region.

Rotary drill bits

A drag-type drill bit for drilling holes in subsurface formations comprises a bit body having an end face and a shank for connection to a drill string, a number of blades upstanding from the end face of the bit body and extending outwardly away from the central axis of rotation of the bit, a number of cutters mounted on each blade, and a number of nozzles in the bit body for delivering drilling fluid for cooling and cleaning the cutters. The blades include primary blades which, at their outer ends, are spaced apart around aperipheral gauge portion of the bit, and secondary blades which are spaced circumferentially between adjacent primary blades, each secondary blade having an outer end which terminates at a location inwardly of the gauge portion of the bit. Each primary blade and associated secondary blade may be equivalent, in terms of their combined contribution to the cutting profile, to a single blade which extends continuously from the centre of the bit body to the gauge, but the separation of the blades facilitates the flow of drilling fluid over and between the blades. Also, the increased number of blades may enhance the stability of the drill bit and reduce vibration.

Split blade rotary drag type drill bits

A rotary drag-type drill bit, for drilling holes in subsurface formations, comprises a bit body having a leading face and a gauge region, a number of blades formed on the leading face of the bit and extending outwardly away from the axis of the bit so as to define between the blades fluid channels leading towards junk slots in the gauge region. Cutting elements are mounted along each blade, and nozzles in the bit body supply drilling fluid to the leading face of the bit for cleaning and cooling the cutting elements. At least some of said blades each have a leading edge which is non-linear, or convexly or concavely curved, as viewed axially of the bit, as it extends outwardly away from the axis of the bit. Blades of different shapes may be located alternately around the axis of the bit. The junk slots at the gauge region, and the kickers between which they are formed, may vary in width around the periphery of the bit, and may be inclined to the axis of the bit.

A rotary drill bit for use in drilling holes in subsurface formations comprises a bit body having a leading face and a gauge region, a number of blades formed on the leading face of the bit and extending outwardly away from the axis of the bit so as to define between the blades a number of fluid channels leading towards the gauge region, a number of cutting elements mounted side-by-side along each blade, and a number of nozzles in the bit body for supplying drilling fluid to the fluid channels for cleaning and cooling the cutting elements. In at least one of the fluid channels, adjacent the gauge region, is an opening into an enclosed passage which passes internally through the bit body to an outlet which, in use, communicates with the annulus between the drill string and the wall of the borehole being drilled. The portion of the gauge region outwardly of the opening comprises a bearing surface which, in use bears against the wall of the bore hole and extends across the width of the channel.

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Cheltenham, United Kingdom

Steven Taylor