Roller cone drill bits with enhanced drilling stability and extended life of associated bearings and seals
First Claim
Patent Images
1. A roller cone drill bit comprising:
- a bit body having at least one support arm extending therefrom;
a cone assembly rotatably mounted on the at least one support arm for engagement with a subterranean formation to form a wellbore;
the cone assembly having a respective axis of rotation extending from the associated support arm;
the cone assembly having a backface disposed adjacent the at least one support arm;
the cone assembly having a plurality of cutting elements;
every cutting element on the cone assembly being either a gauge cutting element or a non-gauge cutting element, the gauge elements arranged in a gauge row located adjacent the backface of the cone assembly;
each cutting element having a crest extending from the associated cone assembly for engagement with the formation;
each crest having a respective crest point defined as a point located a greater distance from the axis of rotation of the associated cone assembly as compared with the distance between any other point on the crest and the axis of rotation of the associated cone assembly;
each cutting element having a normal force axis extending from the cone assembly through the respective crest point; and
every non-gauge cutting element on the cone assembly configured such that the normal force axis of every non-gauge cutting element intersects with each other proximate a force center selected to minimize the wobble effects on the cone assembly due to normal forces from the cutting elements impacting the formation as the cone assembly rotates.
1 Assignment
0 Petitions
Accused Products
Abstract
Roller cone drill bits may be formed with cutting elements and cutting structures having cutting element profile angles selected to minimize cone wobble and improve life of associated bearings and seals. Normal force axes of the cutting elements may intersect with each other as a force center. Crest points of the cutting elements may be disposed on one or more circles extending from the associated force center.
122 Citations
33 Claims
-
1. A roller cone drill bit comprising:
-
a bit body having at least one support arm extending therefrom; a cone assembly rotatably mounted on the at least one support arm for engagement with a subterranean formation to form a wellbore; the cone assembly having a respective axis of rotation extending from the associated support arm; the cone assembly having a backface disposed adjacent the at least one support arm; the cone assembly having a plurality of cutting elements; every cutting element on the cone assembly being either a gauge cutting element or a non-gauge cutting element, the gauge elements arranged in a gauge row located adjacent the backface of the cone assembly; each cutting element having a crest extending from the associated cone assembly for engagement with the formation; each crest having a respective crest point defined as a point located a greater distance from the axis of rotation of the associated cone assembly as compared with the distance between any other point on the crest and the axis of rotation of the associated cone assembly; each cutting element having a normal force axis extending from the cone assembly through the respective crest point; and every non-gauge cutting element on the cone assembly configured such that the normal force axis of every non-gauge cutting element intersects with each other proximate a force center selected to minimize the wobble effects on the cone assembly due to normal forces from the cutting elements impacting the formation as the cone assembly rotates. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. A roller cone drill bit comprising:
-
a bit body having at least one support arm extending therefrom; a cone assembly rotatably mounted on the at least one support arm for engagement with a subterranean formation to form a wellbore; the cone assembly having a gauge row of cutting elements; the cone assembly having four or more rows of cutting elements spaced from the gauge row; the four or more rows of cutting elements spaced from each other; each cutting element having a crest extending from the associated cone assembly for engagement with adjacent portions of the formation; the cone assembly having an axis of rotation extending from the respective support arm; each cutting element having a normal force axis extending from the respective crest; each cutting element having a respective cutting element profile angle defined in part by an intersection of the respective normal force axis and the axis of rotation of the associated cone assembly; and the cutting element profile angles associated with each cutting element in the four or more rows of cutting elements selected so that the normal force axes of each cutting element intersect at a common force center. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
-
-
21. A method for forming a roller cone drill bit with enhanced drilling ability comprising:
-
forming a bit body with at least one support arm extending therefrom; rotatably mounting a cone assembly on the at least one support arm, the cone assembly having a backface disposed adjacent the at least one support arm; forming a plurality of cutting elements on the cone assembly with each cutting element having a crest extending from the cone assembly for engagement with the formation, and with every cutting element on the cone assembly being either a gauge cutting element or a non-gauge cutting element, the gauge cutting elements arranged in a gauge row located adjacent the backface of the cone assembly; selecting a location and orientation for each non-gauge cutting element with its respective normal force axis intersecting at a single force center; and selecting the location of the single force center to reduce wobble of the cone assembly and provide improved drilling stability of the drill bit. - View Dependent Claims (22, 23, 24)
-
-
25. A roller cone drill bit operable to form a wellbore in a subterranean formation comprising:
-
a bit body having at least one support arm extending therefrom; a cone assembly rotatably mounted on the at least one support arm; the cone assembly having a respective axis of rotation extending from the at least one support arm; the cone assembly having a plurality of cutting elements; each cutting element having a crest extending from the associated cone assembly for engagement with the formation; each crest having a respective crest point defined as a point located a greater distance from the axis of rotation of the cone assembly as compared with the distance between any other point on the crest and the axis of rotation of the cone assembly; each cutting element having a normal force axis extending from the cone assembly through the respective crest point; the cone assembly having a respective cone assembly profile defined in part as a combined projection of the crests of all cutting elements onto a plane passing through the axis of rotation of the cone assembly; and the normal force axes of every one of the plurality of cutting elements intersecting with each other proximate a force center. - View Dependent Claims (26, 27, 28, 29)
-
-
30. A roller cone drill bit operable to form a wellbore in a subterranean formation comprising:
-
a bit body having at least one support arm extending therefrom; a cone assembly rotatably mounted on the at least one support arm; the cone assembly having a respective axis of rotation extending from the at least one support arm; the cone assembly having a plurality of cutting elements; each cutting element having a crest extending from the cone assembly for engagement with the formation; each crest having a respective crest point defined as a point located a greater distance from the axis of rotation of the cone assembly as compared with the distance between any other point on the crest and the axis of rotation of the cone assembly; each cutting element having a normal force axis extending from the cone assembly through the respective crest point; the cone assembly having a respective cone assembly profile defined in part as a combined projection of the crests of all cutting elements onto a plane passing through the axis of rotation of the cone assembly; the normal force axes of each one of the plurality of cutting elements intersecting with each other proximate a force center; each cutting element having a respective cutting zone with the respective crest point located proximate the center of the respective cutting zone; and at least one row of cutting elements on the cone assembly having the respective crest points located at approximately the same radial distance from the force center. - View Dependent Claims (31, 32, 33)
-
Specification