Abstract: Embodiments of a reamer of the present invention generally include a substantially tubular body sub, a substantially planar base plate having one or more receiving cavities disposed therein, one or more gussets, a fluid chamber, and a plurality of leg/cone assemblies having a leg end and a cone end; wherein the base plate is disposed around the body sub and stabilized by the gussets, and each leg end comprises an exterior surface geometry complementary to the interior surface geometry of a base plate receiving cavity and is insertable into and affixable therein. The receiving cavities are constructed in defined locations and orientations in the base plate and the leg/cone assemblies are precisely formed such that insertion of the leg end into the receiving cavity accurately and precisely disposes the cutting component about the reamer. Embodiments of methods of providing and using an apparatus of the present invention are also provided.

Abstract: Repeated percussive forces may be provided using various devices, systems, assemblies, and methods. Example rotary percussive devices may be used in a downhole environment, including within a drilling system that includes a percussive hammer drill bit. The rotary percussive device may include a rotational translator to convert drilling fluid pressure into a rotational force. An axial translator coupled to the rotational translator may convert the rotational force into an axial percussive force. This conversion may be done using magnets arranged in arrays of alternating polarities. The rotational translator may longitudinally overlap the axial translator. The rotational translator may include a rotational stator rotationally fixed within a bottomhole assembly. The rotational stator may include a shaft of a positive displacement motor.

Abstract: Embodiments of a reamer of the present invention generally include a substantially tubular body sub, a substantially planar base plate having one or more receiving cavities disposed therein, one or more gussets, a fluid chamber, and a plurality of leg/cone assemblies having a leg end and a cone end; wherein the base plate is disposed around the body sub and stabilized by the gussets, and each leg end comprises an exterior surface geometry complementary to the interior surface geometry of a base plate receiving cavity and is insertable into and affixable therein. The receiving cavities are constructed in defined locations and orientations in the base plate and the leg/cone assemblies are precisely formed such that insertion of the leg end into the receiving cavity accurately and precisely disposes the cutting component about the reamer. Embodiments of methods of providing and using an apparatus of the present invention are also provided.

Abstract: Repeated percussive forces may be provided using various devices, systems, assemblies, and methods. Example rotary percussive devices may be used in a downhole environment, including within a drilling system that includes a percussive hammer drill bit. The rotary percussive device may include a rotational translator to convert drilling fluid pressure into a rotational force. An axial translator coupled to the rotational translator may convert the rotational force into an axial percussive force. This conversion may be done using magnets arranged in arrays of alternating polarities. The rotational translator may longitudinally overlap the axial translator. The rotational translator may include a rotational stator rotationally fixed within a bottomhole assembly. The rotational stator may include a shaft of a positive displacement motor.

Abstract: A percussion drilling assembly includes a housing and a drill bit within a lower end of the housing. At least one of a piston or an anvil is within the housing above the drill bit. The drilling assembly also includes at least one sensor in at least one of the housing, the piston, or the anvil. A method of drilling includes drilling a formation with a percussion drilling assembly, the percussion drilling assembly having at least one sensor located in a component thereof. The at least one sensor may measure at least one property of the percussion drilling assembly while drilling. The measurements taken by the at least one sensor may be analyzed and a new percussion drilling assembly designed based on the analysis.

Abstract: A percussion drilling assembly includes a housing with a hammer bit disposed in the lower end portion thereof and configured to move longitudinally within the housing. The hammer bit includes an annular bit shank having a bit strike face and a cutting structure at a lower end portion thereof. An annular piston having a piston strike face arranged and designed to strike the bit strike face is also disposed in the housing. At least one of the bit strike face and the piston strike face has a toroidal curvature profile. A method includes one or more of lowering the percussion drilling assembly into a borehole, engaging the cutting structure with a formation, and impacting the bit strike face of the annular bit shank with the piston strike face of the annular piston.

Abstract: A cutting insert for a percussion hammer bit. The cutting insert includes a base portion for coupling to a bit face of the percussion hammer bit. An extension portion is coupled to the base portion and axially offset therefrom along a longitudinal axis extending through the base portion and the extension portion. The extension portion includes at least three lobes that are circumferentially offset from one another around the longitudinal axis. The lobes extend axially away from the base portion, and the lobes extend radially outward from the longitudinal axis.

Abstract: A roller cone drill bit having a bit body. The bit body has a journal bearing coupled to an end portion thereof. A roller cone is coupled to the journal bearing. A first cutting element is coupled to the roller cone. A ratio of a radius of curvature of a crest portion of the first cutting element to a diameter of the first cutting element is between about 0.3:1 and about 0.8:1. A second cutting element is coupled to the roller cone. A ratio of a radius of curvature of a crest portion of the second cutting element to a diameter of the second cutting element is between about 0.05:1 and about 0.3:1. A height of the second cutting element is greater than the height of the first cutting element h between about 0.1 mm and about 6 mm.

Abstract: A percussion drill bit for drilling a borehole. The drill bit includes a bit body having a bit face disposed on an axial end portion thereof. First and second cutting elements are disposed on the bit face. A cutting plane is defined in tangential contact with crest portion of the first and second cutting elements. A third cutting element on the bit face is at least partially positioned between the first and second cutting elements. The third cutting element is at least partially conical, and a crest portion of the third cutting element is offset from the cutting plane.

Abstract: A percussion drilling assembly includes a housing with a hammer bit disposed in the lower end portion thereof and configured to move longitudinally within the housing. The hammer bit includes an annular bit shank having a bit strike face and a cutting structure at a lower end portion thereof. An annular piston having a piston strike face arranged and designed to strike the bit strike face is also disposed in the housing. At least one of the bit strike face and the piston strike face has a toroidal curvature profile. A method includes one or more of lowering the percussion drilling assembly into a borehole, engaging the cutting structure with a formation, and impacting the bit strike face of the annular bit shank with the piston strike face of the annular piston.

Abstract: A percussion drilling assembly for drilling a borehole, the assembly including a tubular casing having a central axis defined therethrough and a lower end, a driver sub having an upper end threadingly engaged with the lower end of the tubular casing, and an annular locking member disposed between the tubular easing and the driver sub. The annular locking member is configured to engage the tubular casing and the driver sub, and is configured to prevent separation of the driver sub from the tubular casing. The annular locking member includes a deformable elongate member.

Abstract: A back reamer includes a drive stem configured to support a main reamer body, the main reamer body including a plurality of receptacles, and a plurality of cutting leg assemblies in positive locking engagement with the plurality of receptacles to restrict radial movement of the cutting leg assemblies.

Abstract: A modular back reamer to be used in subterranean drilling includes a drive stem connected to a drill string and configured to support a reamer body, the reamer body providing a plurality of receptacles, wherein the receptacles are configured to retain a cutting leg assembly at varying heights within a predetermined range, and a plurality of shims engaged within the receptacles to secure the cutting leg assemblies at a specified height within the predetermined range, wherein the cutting leg assembly is secured to the reamer body with at least one mechanical fastener.

Abstract: A back reamer includes a drive stem configured to support a main reamer body, the main reamer body including a plurality of receptacles, and a plurality of cutting leg assemblies in positive locking engagement with the plurality of receptacles to restrict radial movement of the cutting leg assemblies.

Abstract: A modular back reamer to be used in subterranean drilling includes a drive stem connected to a drill string and configured to support a reamer body, the reamer body providing a plurality of receptacles, wherein the receptacles are configured to retain a cutting leg assembly at varying heights within a predetermined range, and a plurality of shims engaged within the receptacles to secure the cutting leg assemblies at a specified height within the predetermined range, wherein the cutting leg assembly is secured to the reamer body with at least one mechanical fastener.

Abstract: Methods and apparatus for maintaining lubrication of rolling cone cutters mounted on journal pins. Embodiments comprise a rotating cone disposed on a journal pin and forming a journal gap there between. A cylindrical journal sleeve is disposed in the journal gap. The journal sleeve has a longitudinal gap forming opposing end portions, which are continuously contoured. A lubrication port is disposed in the journal pin and in fluid communication with a lubrication supply. The lubrication port has an outlet located in a recess in the journal gap. Each end of the recess comprises a transitioning surface extending between the bottom of the recess and the outer surface of the journal pin to prevent sharp transitions. In certain embodiments, the journal pin may comprise two or more lubrication ports, each located in a recess with transitioning surfaces.

Abstract: A method of forming a drill bit structure, the method including fixing spacers to the drill bit structure. The spacers are arranged at preselected locations on an outer surface of the drill bit structure. A hardfacing material is then applied to the drill bit structure, and the spacers are removed. Holes are machined in the drill bit structure at the preselected locations, and drilling inserts are positioned in each hole. A method of forming a drill bit structure, the method including applying a hardfacing material to selected surfaces of the drill bit structure. The hardfacing material includes a perforated carbide infiltrated material and a perforated powder infiltrated material. The perforations in the powder infiltrated material correspond to the perforations in the carbide infiltrated material. Holes are machined in the drill bit structure at the locations of the perforations, and drilling inserts are positioned in each hole.

Abstract: A back reaming tool is disclosed which includes a tool body adapted to be coupled to a drill string, and at least cutting structure mounted to a leg and having cutting elements disposed thereon. The leg is removably coupled to the tool body.

Abstract: A method of forming a drill bit structure, the method including fixing spacers to the drill bit structure. The spacers are arranged at preselected locations on an outer surface of the drill bit structure. A hardfacing material is then applied to the drill bit structure, and the spacers are removed. Holes are machined in the drill bit structure at the preselected locations, and drilling inserts are positioned in each hole. A method of forming a drill bit structure, the method including applying a hardfacing material to selected surfaces of the drill bit structure. The hardfacing material includes a perforated carbide infiltrated material and a perforated powder infiltrated material. The perforations in the powder infiltrated material correspond to the perforations in the carbide infiltrated material. Holes are machined in the drill bit structure at the locations of the perforations, and drilling inserts are positioned in each hole.

Abstract: A drill bit for use in a borehole at least partially containing drilling fluid includes a bit body having at least two bit components, including at least one leg, the leg having a journal segment, and a roller cone rotatably mounted upon the journal segment and forming at least one bearing cavity therebetween. Also included is an annular primary seal disposed between the leg and the roller cone, an annular secondary seal disposed between the leg and the roller cone and between the annular primary seal and the borehole and an annular space disposed between the annular primary seal and the annular secondary seal, the annular space at least partially containing fluid and being in substantially absolute fluid isolation from the bearing cavity and a conduit for permitting the flow of fluid from the annular space to the borehole. The annular secondary seal may be primarily elastomeric and the means for permitting the flow of fluid may further permit the flow of fluid from the borehole to the annular space.