# US 2014/0196956 A1 · High shear roller cone drill bits > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0196956 A1 - Document ID: US20140196956A1 - Status: Published application - Kind: A1 - Application number: 14/212,404 - Filed: 2014-03-14 - Published: 2014-07-17 - Earliest claimed: 2009-07-31 - Assignees: Smith International, Inc. - Applicants: Smith International, Inc. - Inventors: Prabhakaran K. Centala; Zhehua Zhang - Web page: https://patentgrep.com/patent/US20140196956A1 ## CPC - E21B 10/22: characterised by bearing, lubrication or sealing details - E21B 10/08: Roller bits (E21B10/26 takes precedence; roller core bits E21B10/06; characterised by wear resisting parts E21B10/50) - E21B 10/18: characterised by conduits or nozzles for drilling fluids - E21B 10/50: the bit being of roller type - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS ## 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. ## Claims ### Claim 1 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. ### Claim 2 (depends on 1) The drill bit of claim 1, wherein the bit body is shaped to have its lowest diameter at an axial location below its greatest diameter. ### Claim 3 (depends on 1) The drill bit of claim 1, wherein each angle φ between the longitudinal axis of the bit and each journal axis of the plurality of journals is an acute angle. ### Claim 4 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. ### Claim 5 (depends on 4) The drill bit of claim 4, wherein the plurality of roller cones is oriented to form a center core spacing therebetween. ### Claim 6 (depends on 5) The drill bit of claim 5, wherein the at least one cutting element comprises a center insert disposed in a center hole of the lower end of the bit body between the plurality of roller cones. ### Claim 7 (depends on 6) The drill bit of claim 6, wherein the center insert is configured to assist in cutting of a center core of formation. ### Claim 8 (depends on 6) The drill bit of claim 6, comprising: a plurality of ball passages; a plurality of ball retainers each disposed in the plurality of ball passages; and a center plug disposed in a center of the lower end of the bit body proximate the plurality of ball retainers. ### Claim 9 (depends on 8) The drill bit of claim 8, wherein the center plug includes at least one groove formed therein configured to receive at least one of the plurality of ball retainers. ### Claim 10 (depends on 8) The drill bit of claim 8, wherein at least two of the plurality of ball retainers have a different length. ### Claim 11 (depends on 8) The drill bit of claim 8, comprising a back hole plug disposed in at least one of the plurality of ball passages. ### Claim 12 (depends on 4) The drill bit of claim 4, comprising at least one grease hole and a plurality of lubrication passages for each cone, wherein the plurality of lubrication passages do not intersect. ### Claim 13 (depends on 6) The drill bit of claim 6, wherein the center insert is secured in the center hole with an interference fit. ### Claim 14 (depends on 4) The drill bit of claim 4, wherein each of the plurality of roller cones includes a plurality of cutting elements thereon, at least one cutting element on an outermost row of at least one roller cone comprising an extension height to diameter ratio ranging from 0.675 to 0.76. ### Claim 15 (depends on 5) The drill bit of claim 5, wherein at least one cutting element configured to engage the formation proximate the bit centerline engages a center core of formation formed by the center core spacing. ### Claim 16 (depends on 15) The drill bit of claim 15, wherein the at least one cutting element is on a core-facing surface of the at least one roller cone. ### Claim 17 (depends on 4) The drill bit of claim 4, wherein at least one roller cone touches the bit centerline. ### Claim 18 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. ### Claim 19 (depends on 18) The drill bit of claim 18, wherein the second, different type of cutting structure includes a center insert disposed in a center hole of the lower end of the bit body. ### Claim 20 (depends on 18) The drill bit of claim 18, wherein at least one nozzle is disposed between each pair of adjacent roller cones. ### Claim 21 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.