There is disclosed herein a method of molding an object by infiltrating a matrix material with an infiltration material, the method including providing first and second zones of respective different first and second matrix materials arranged substantially adjacent to each other in a mold, including forming a transition region between the two zones through which the composition of the material in the transition region is gradually varied from the composition of the first matrix material adjacent the first zone to the composition of the second matrix material near the second zone.

There is disclosed herein a method of molding an object by infiltrating a matrix material with an infiltration material, the method including providing first and second zones of respective different first and second matrix materials arranged substantially adjacent to each other in a mold, including forming a transition region between the two zones through which the composition of the material in the transition region is gradually varied from the composition of the first matrix material adjacent the first zone to the composition of the second matrix material near the second zone.

A Polycrystalline Diamond Compact (PDC) cutter for a rotary drill bit is provided with an integrated sensor and circuitry for making measurements of a property of a fluid in the borehole and/or an operating condition of the drill bit. A method of manufacture of the PDC cutter and the rotary drill bit is discussed.

A method of improving the service life of a drill bit comprises creating a weldment between load bearing portions of the drill bit where the weldment has a preselected root gap greater than about 25 mils and a preselected root face greater than about 25 mils, and where the weldment has a material property greater than the materials being joined.

Bottom hole assemblies for drilling through a lost circulation zone of a wellbore includes a drill string, a drill bit and a cladding seat coupled to the drill string, an expandable cladding sheath engaged with the cladding seat, a release mechanism coupling an uphole end of the expandable cladding sheath to the drill string, and an expander translatable axially along the drill string. The expandable cladding sheath is a fiber reinforced polymer. The cladding seat releasably couples a downhole end of the expandable cladding sheath to the drill string, and the release mechanism operates to release the uphole end of the expandable cladding sheath from the drill string. The expander deforms the expandable cladding sheath outward into contact with a wall of a wellbore when translated axially through a central cavity of the expandable cladding sheath. The bottom hole assembly may enable drilling ahead through a lost circulation zone.

Bottom hole assemblies for drilling through a lost circulation zone of a wellbore includes a drill string, a drill bit and a cladding seat coupled to the drill string, an expandable cladding sheath engaged with the cladding seat, a release mechanism coupling an uphole end of the expandable cladding sheath to the drill string, and an expander translatable axially along the drill string. The expandable cladding sheath is a fiber reinforced polymer. The cladding seat releasably couples a downhole end of the expandable cladding sheath to the drill string, and the release mechanism operates to release the uphole end of the expandable cladding sheath from the drill string. The expander deforms the expandable cladding sheath outward into contact with a wall of a wellbore when translated axially through a central cavity of the expandable cladding sheath. The bottom hole assembly may enable drilling ahead through a lost circulation zone.

A rotary drill bit for directional drilling operations, in which a rotating bit with cutters advances a borehole in the earth invention, provides a smaller radius of curvature to increase drilling efficiency. The rotary drill bit comprises a box connection for connecting the bit to the drill string. The drill bit receives a pin connection that seats adjacent the plenum of the bit to shorten the distance between the bit face and steering tools behind the bit so the drill string can be steered more efficiently.

An example apparatus includes a drill bit body and a leg extending from the drill bit body. A journal may extend from the leg, with a gamma ray detector at least partially within the journal. In certain embodiments, the gamma ray detector may be confined within a pressure protective cavity at least partially within the arm of the journal. In certain embodiments, the gamma ray detector may be a scintillator aligned with at least one of a photomultiplier, photodiodes, or phototransistors.

A stop collar for a tubular and method for installing a stop collar on a tubular. The stop collar includes a flexible member extending circumferentially around the tubular more than once. A tension force on the flexible member causes the flexible member to apply a radially-inward gripping force on the tubular. The stop collar may also include a shield disposed around at least a portion of the flexible member, to protect the flexible member in a downhole environment. The stop collar may also or instead include an adhesive disposed radially between the flexible member and the tubular.

A stop collar for a tubular and method for installing a stop collar on a tubular. The stop collar includes a flexible member extending circumferentially around the tubular more than once. A tension force on the flexible member causes the flexible member to apply a radially-inward gripping force on the tubular. The stop collar may also include a shield disposed around at least a portion of the flexible member, to protect the flexible member in a downhole environment. The stop collar may also or instead include an adhesive disposed radially between the flexible member and the tubular.