High shear roller cone drill bits
AssigneeSmith International, Inc.
InventorsPrabhakaran K. Centala, Zhehua Zhang
Life of this patent
Estimating the term…
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.
Claims21
A drill bit, comprising:
- a bit body, comprising:
- at the upper end of the bit body, a connection adapted to connect to a drill string;
- and
- at the lower end of the bit body, a plurality of journals extending downwardly and radially outward from a longitudinal axis of the bit;
- a plurality of roller cones rotatably mounted on the plurality of journals,
- wherein a ratio of a distance from the longitudinal axis to a greatest diameter of the cone and a bit radius is in a range of 0 to 0.25.
A drill bit, comprising:
- a bit body, comprising:
- at the upper end of the bit body, a connection adapted to connect to a drill string;
- and
- at the lower end of the bit body, a plurality of journals extending downwardly and radially outward from a longitudinal axis of the bit;
- a plurality of roller cones rotatably mounted on the plurality of journals;
- and
- at least one cutting element configured to engage earth formation proximate a bit centerline.
A drill bit, comprising:
- a bit body, comprising:
- at the upper end of the bit body, a connection adapted to connect to a drill string;
- and
- at the lower end of the bit body, a first cutting structure and a second, different type of cutting structure, the first cutting structure including a plurality of journals extending downwardly and radially outward from a longitudinal axis of the bit and a plurality of roller cones rotatably mounted on the plurality of journals.
A drill bit, comprising:
- a bit body, comprising:
- at the upper end of the bit body, a connection adapted to connect to a drill string;
- and
- at the lower end of the bit body, a plurality of journals;
- a plurality of roller cones rotatably mounted on the plurality of journals;
- and
- a center insert disposed in a center hole of the lower end of the bit body between the plurality of roller cones configured to engage earth formation proximate a bit centerline.
Dependencies are inferred from the claim text.