Abstract: A wellhead latch assembly may include one or more latches for attaching to a wellhead and allowing removal of the wellhead during a well abandonment process. The wellhead latch assembly may include an inner core coupled to the latches, and an outer sleeve for selectively latching and unlatching the latches to the wellhead. The inner core may abut the wellhead and can include a groove having circumferential and/or longitudinal features. The outer sleeve may include a pin which travels within the groove and a set of cut-outs for alignment with the latches. When the cut-outs align with the latches, the latches may expand radially outward and disengage the wellhead. As the outer sleeve moves axially or rotationally relative to the inner core, the latches may fall out of alignment with the cut-outs and move radially inwardly to engage or capture the wellhead.

Abstract: A wellhead latch assembly may include one or more latches for attaching to a wellhead and allowing removal of the wellhead during a well abandonment process. The wellhead latch assembly may include an inner core coupled to the latches, and an outer sleeve for selectively latching and unlatching the latches to the wellhead. The inner core may abut the wellhead and can include a groove having circumferential and/or longitudinal features. The outer sleeve may include a pin which travels within the groove and a set of cut-outs for alignment with the latches. When the cut-outs align with the latches, the latches may expand radially outward and disengage the wellhead. As the outer sleeve moves axially or rotationally relative to the inner core, the latches may fall out of alignment with the cut-outs and move radially inwardly to engage or capture the wellhead.

Abstract: A wellhead latch assembly may include one or more latches for attaching to a wellhead and allowing removal of the wellhead during a well abandonment process. The wellhead latch assembly may include an inner core coupled to the latches, and an outer sleeve for selectively latching and unlatching the latches to the wellhead. The inner core may abut the wellhead and can include a groove having circumferential and/or longitudinal features. The outer sleeve may include a pin which travels within the groove and a set of cut-outs for alignment with the latches. When the cut-outs align with the latches, the latches may expand radially outward and disengage the wellhead. As the outer sleeve moves axially or rotationally relative to the inner core, the latches may fall out of alignment with the cut-outs and move radially inwardly to engage or capture the wellhead.

Abstract: 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 cutter assemblies 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 cleaning the cutter assemblies. At least some of the cutter assemblies each comprise a cutting element on a stud which is recveived in a socket in the bit body, the centerline of the stud being disposed at an angle to the normal direction of forward movement of the cutter assembly in use of the bit. At least three of such cutter assemblies are disposed closely adjacent one another in a row, adjacent cutter assemblies in the row having their centerlines inclined at different angles to allow closer packing of the cutter assemblies.

Abstract: A drill bit for drilling deep holes in subsurface formations comprises a bit body having a generally hemispherical leading face and a gauge region, and two blades each extending spirally outwardly across the leading face of the bit body away from the axis of rotation, a cavity of substantial peripheral and axial extent being formed in the bit body on the forward side of each blade, and communicating with an associated exit channel in the gauge region. A plurality of cutting elements are mounted along each blade, the cutting elements being mounted closely adjacent one another side-by-side along the blade so that their cutting edges together form a single long cutting edge without substantial discontinuities. A passage in the bit body supplies drilling fluid to nozzles in the cavities for cooling and cleaning the cutting elements, fluid from the nozzles sweeping past the cutting elements and out through the exit channels.

Abstract: A method of forming a cutting structure for a rotary drill bit comprises brazing a thermally stable polycrystalline diamond cutting element to a carrier, the carrier being formed of a material such that, at the brazing temperature, the difference in coefficient of thermal expansion between said material and the polycrystalline diamond material is less than the difference in coefficient of thermal expansion between tungsten carbide and the polycrystalline diamond material. A suitable carrier material is silicon carbide.

Abstract: A cutter assembly, for a rotary drill bit, comprises a generally cylindrical stud to be received in a socket in the surface of the bit body, the stud being formed, adjacent one end thereof, with a plane surface inclined at an angle of less than 90.degree. to the longitudinal axis of the stud, and a preform cutting element mounted on the inclined surface. The dimensions of the cutting element, and its location on the inclined surface, are such that no part of the cutting element projects beyond the peripheral surface of the stud as viewed axially thereof. The cutting element may be so shaped and located that it initially projects beyond the peripheral surface of the stud, the projecting portions subsequently being removed, for example by grinding.

Abstract: A method of forming a cutting structure for a rotary drill bit comprises brazing a thermally stable polycrystalline diamond cutting element to a carrier, the carrier being formed of a material such that, at the brazing temperature, the difference in coefficient of thermal expansion between said material and the polycrystalline diamond material is less than the difference in coefficient of thermal expansion between tungsten carbide and the polycrystalline diamond material. A suitable carrier material is silicon carbide.

Abstract: A cutting element for a rotary drill bit comprises a thin hard facing layer, defining a front cutting face, bonded to a less hard backing layer. The backing layer is of non-uniform thickness, for example is wedge-shaped, and is thicker adjacent the cutting edge of the facing layer than it is over the rest of the area of the facing layer. The rear surface of the backing layer of the cutting element is bonded to a surface on a carrier which is mounted in the bit body. The backing layer of the cutting element may be formed in two portions: a front portion which is bonded to the hard facing layer and a second, wedge-shaped portion which is bonded subsequently to the rear surface of the first portion.