Drill bit reinforcing members or blanks of this invention are formed from high-strength steels having a carbon content less than about 0.3 percent by weight, a yield strength of at least 55,000 psi, a tensile strength of at least 80,000 psi, a toughness of at least 40 CVN-L, Ft-lb, and a rate of expansion percentage change less than about 0.0025%/.degree. F. during austenitic to ferritic phase transformation. In one embodiment, such steel comprises in the range of from about 0.1 to 0.3 percent b...

A cutter element for a rolling cone bit includes a cutting surface having front and back surfaces, a pair of flanking surfaces that intersect in a rounded nose that is offset from the central axis of the cutter element's base. At least one flanking surface includes a concave region. The back surface presents a generally wedge-shaped top profile.

An insert for a rock bit that includes tungsten carbide particles, and a cobalt binder disposed around the particles, wherein a grain size of the tungsten carbide particles and a content of the cobalt binder are selected to provide a fracture toughness of at least about 18 ksi (in).sup.0.5, a wear number of at least about 2, and a hardness of 85 to 87 Ra is disclosed.

The present invention relates to methods and equipment for recovering use of a well-bore in circumstances where the well bore has become blocked by downhole equipment. The invention provides a method comprising the steps of separating, at a release joint, a portion of equipment from a jammed portion (6) of equipment; running the separated portion of equipment uphole out of the wellbore (100); running a deflector assembly (60) downhole into the wellbore (100); and deflecting a milling tool (64) f...

Cutting elements having coarse grain substrates and ultra hard material layers are provided. The substrates are formed from coarse grain size particles of tungsten carbide. A method of forming such cutting elements and a drag bit incorporating such cutting elements are also provided.

The present invention relates to downhole apparatus for limiting rotation of a rotor (4) relative to a stator (8) associated with said rotor (4). Apparatus according to the invention is provided with a locking member (12) movable from a first axial position to a second axial position by the application of a static fluid pressure to a differential area of said locking member (12). The apparatus is characterised by means for selectively applying static fluid pressure to said differential area of s...

The present invention relates to the completion of lateral well bores and provides a method comprising the steps of installing a datum device in a main well bore so as to provide a datum height above the lateral: making a completion string (10) comprising a lateral lining (11), a window element (14) at an upper end of the lining (11), a swivel joint (15) located between the lining (11) and the window element (14), and a datum device engaging member (21) located above the window element (14); run...

A novel rolling cone rock bit includes a plurality of PDC or other cutters mounted to the leg of the drill bit and positioned to cut the troublesome corner of the bottomhole. The plurality of cutters may be the primary cutting component at gage diameter, or may be redundant to gage teeth on a rolling cutter that cut to gage diameter. Consequently, the occurrence of undergage drilling from the wear and failure of the gage row on a rolling cutter is lessened. Another inventive feature is the inclu...

A drill bit that includes a bit body, at least one roller cone attached to the bit body and able to rotate with respect to the bit body, a plurality of cutting elements disposed on the at least one roller cone, and a barrel axis is disclosed. At least one of the plurality of cutting elements includes a first area defining a secondary wear surface, wherein the first area is formed as a convex surface on the trailing edge, a second area proximate the first area defining a main wear surface, wherei...

The present invention relates to a roller cone drill bit that has improved flow characteristics. The roller cone drill bit includes forming at least one relief region inside a bit body of the roller cone drill bit on a ledge formed between a fluid plenum and at least one of the fluid orifices. A method of locating the at least one relief region is also disclosed.