Abstract: The invention provides an improved drill bit and a method for designing thereof. The drill bit includes a bit body, a journal depending from the bit body, and a disc rotatably mounted on the journal. The disc of the drill bit has PDC cutting elements disposed on it. Also provided is an improved cutting structure for the discs of the drill bit. The cutting structure includes a portion that is comprised from PDC.

Abstract: A method of manufacturing a roller cone drill bit may include forming a body of a single piece having an upper end and a lower end; machining at the lower end of the body at least two journals extending downward and radially outward from a central axis of the body; machining at least one of a ball passage, a hydraulic fluid passageway, a grease reservoir, and a lubricant passageway; and mounting roller cones on the at least two journals.

Abstract: A drill bit may include a bit body, comprising: at its upper end, a connection adapted to connect to a drill string; at its lower end, a plurality of journals extending downwardly and radially outward from a longitudinal axis of the bit; a plurality of roller cones rotatable mounted on the plurality of journals; and at least three rows of cutting elements disposed on each of the plurality of roller cones, wherein an outermost row has an extension height to diameter ratio greater than a mid row, and the mid has an extension height to diameter ratio greater than an innermost row.

Abstract: A drill bit includes a bit body comprising at its upper end a connection adapted to connect to a drill string and at its lower end a plurality of journals extending downwardly and radially outward from a longitudinal axis of the bit. A plurality of roller cones are rotatably mounted on the plurality of journals and at least three rows of cutting elements are disposed on each of the plurality of roller cones. The outermost row of the at least three rows of cutting elements has an extension height to diameter ratio greater than a mid row, and the mid row has an extension height to diameter ratio greater than an innermost row.

Abstract: A method for designing a drill bit in an earth formation, including defining parameters for a simulation of the drill bit drilling in earth formation, where the parameters comprise at least bit design parameters; executing the defined simulation; obtaining radial forces resulting from the executing of the defined simulation; applying a criterion to the obtained radial forces; and adjusting one of the at least bit design parameters in response to the applying of the criteria.

Abstract: A method of manufacturing a roller cone drill bit may include forming a body of a single piece having an upper end and a lower end; machining at the lower end of the body at least two journals extending downward and radially outward from a central axis of the body; machining at least one of a ball passage, a hydraulic fluid passageway, a grease reservoir, and a lubricant passageway; and mounting roller cones on the at least two journals.

Abstract: A drill bit may include a bit body, comprising: at its upper end, a connection adapted to connect to a drill string; at its lower end, a plurality of journals extending downwardly and radially outward from a longitudinal axis of the bit; a plurality of roller cones rotatable mounted on the plurality of journals; and at least three rows of cutting elements disposed on each of the plurality of roller cones, wherein an outermost row has an extension height to diameter ratio greater than a mid row, and the mid has an extension height to diameter ratio greater than an innermost row.

Abstract: A two-cone drill bit with a hydraulic arrangement that can be used for one or more of the following: cleaning roller cones, impinging on a hole bottom, or inducing a helical flow field. A two-cone drill bit having a bit body formed from two leg sections and two spacing members. Methods of manufacturing a two-cone drill bit. Methods of improving hydraulics of a two-cone drill bit.

Abstract: A two-cone drill bit with a hydraulic arrangement that can be used for one or more of the following: cleaning roller cones, impinging on a hole bottom, or inducing a helical flow field. A two-cone drill bit having a bit body formed from two leg sections and two spacing members; methods of manufacturing a two-cone drill bit; and methods of improving hydraulics of a two-cone drill bit are disclosed.

Abstract: A two-cone drill bit that exhibits improved stability. In one embodiment, the two-cone drill bit has a first and a second roller cone arranged to have a cone separation angle between about 145 degrees and about 166 degrees. In some embodiments, the two-cone drill bit has a plurality of cutting elements arranged on the roller cones such that a bottom hole coverage greater than about 17 percent is achieved per revolution of the two-cone drill bit.

Abstract: A two-cone drill bit that exhibits improved stability. In one embodiment, the two-cone drill bit has a first and a second roller cone arranged to have a cone separation angle between about 145 degrees and about 166 degrees. In some embodiments, the two-cone drill bit has a plurality of cutting elements arranged on the roller cones such that a bottom hole coverage greater than about 17 percent is achieved per revolution of the two-cone drill bit.

Abstract: A method for designing a drill bit in an earth formation, including defining parameters for a simulation of the drill bit drilling in earth formation, where the parameters comprise at least bit design parameters; executing the defined simulation; obtaining radial forces resulting from the executing of the defined simulation; applying a criterion to the obtained radial forces; and adjusting one of the at least bit design parameters in response to the applying of the criteria.