US 20090159341 A1
An earth boring drill bit comprising cones, each cone having rows of inserts, where the inserts are in the form of a pyramid with four sides. The insert includes ridges at the juncture of each adjacent side. The ridges extend to the top of the insert and meet at a crest. Oppositely disposed ridges on the insert lie substantially in the same plane, thereby forming two planes intersecting on the crest. The two planes are substantially perpendicular. The inserts are arranged on the cone such that one plane is substantially parallel with the insert row, and the other is substantially parallel with the cone axis.
1. An earth boring bit comprising:
a bit body:
a cutter cone rotatingly mounted on the bit body;
a row of inserts arranged on the cutter cone along a ringlike path;
a first ridge on the upper surface of each insert and oriented generally parallel with the cone axis; and
a second ridge on the upper surface of each insert oriented generally parallel with the path and intersecting the first ridge.
2. The earth boring bit of
3. The earth boring bit of
4. The earth boring bit of
5. The earth boring bit of
6. The earth boring bit of
7. The earth boring bit of
8. The earth boring bit of
9. The earth boring bit of
10. An earth boring bit comprising:
a bit body;
roller cones rotatingly attached to the bit body; and
a row of inserts arranged in a substantially circular path on each roller cone outer surface;
each insert having;
a base on the end where it attaches to the roller cone cutter,
a first ridge on its upper surface extending along a line generally parallel with the cone axis,
a second ridge on its upper surface extending along a line generally parallel with the circular path and intersecting the first ridge, and
faces on the upper surface provided between the first and second ridges extending from where the first and second ridges intersect to the base, the faces joining at an angle, so that material displaced during boring operations is directed by the angled faces to open spaces on the bit and not trapped between inserts.
11. The earth boring bit of
12. The earth boring bit of
13. The earth boring bit of
14. The earth boring bit of
15. An earth boring bit comprising:
a bit body;
a roller cone rotatingly attached to the bit body;
inserts on the roller cone having a leading surface and a trailing surface, the inserts oriented so that during boring operations the leading surfaces are in cutting contact with the material being displaced; and
ridges projecting outward from each leading surface to define faces on the sides of the ridges that lie in a plane oblique to the roller cone axes, so that material displaced during boring operations is urged away from the space between adjacent inserts.
This application claims priority to and the benefit of co-pending U.S. Provisional Application Ser. No. 61/016,243, filed Dec. 21, 2007, the full disclosure of which is hereby incorporated by reference herein.
1. Field of Invention
The disclosure herein relates in general to rolling cone earth boring bits, and in particular to the shape and orientation of compacts used on the cones.
2. Description of Prior Art
Drilling systems having earth boring drill bits are used in the oil and gas industry for creating wells drilled into hydrocarbon bearing substrata. Drilling systems typically comprise a drilling rig (not shown) used in conjunction with a rotating drill string wherein the drill bit is disposed on the terminal end of the drill string and used for boring through the subterranean formation.
Drill bits typically are chosen from one of two types, either drag bits or roller cone bits. Rotating the bit body with the cutting elements on the outer surface of the roller cone body crushes the rock and the cuttings may be washed away with drilling fluid. A rolling cone earth boring bit has a bit body with typically three legs. A bearing pin depends from each leg and a cone mounts rotatably to each bearing pin. The cones have rows of cutting teeth on the outer surface of the cone. In one type, the cutting elements comprise teeth machined into the surface of the cone. In another type, the cutting elements comprise carbide compacts or inserts that are pressed-fitted into mating holes in the cone surface.
Compacts generally have a cylindrical base that is inserted into a hole and a protruding cutting tip. The cutting tips may have chisel, hemispherical, ovoid or other shapes. Particularly on the heel row, which is located near the gage surface of each cone, the compacts may have asymmetrical shoulder surfaces for engaging the sidewall of the bore hole. Depending upon the formation being drilled, different shapes are utilized for aggressiveness of cutting and durability.
One example of a roller cone bit is provided in side view in
Disclosed herein is an earth boring drill bit having a roller cone with cutting inserts on the outer surface of the roller cone. The inserts comprise a generally circular base and a peal. The sides of the inserts comprise four faces that extend from the base to the peak. Each face has a generally triangular configuration wherein a portion of its surface is generally planar. The region where adjacent sides join is rounded thereby defining ridges. The four substantially similar sides form four ridges that meet at the crest. A first set of two ridges form on opposite sides of the base with respect to one another and are substantially parallel. A second set of two ridges also form on opposite sides with respect to one another and are also parallel. The inserts are oriented on the cone in rows so that the first set of ridges is aligned with the cone axis and the second set of ridges is aligned with the row.
Some of the features and benefits of the present invention having been stated, others will become apparent as the description proceeds when taken in conjunction with the accompanying drawings, in which:
While the invention will be described in connection with the preferred embodiments, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications, and equivalents, as may be included within the spirit and scope of the invention as defined by the appended claims.
The present invention will now be described more fully hereinafter with reference to the accompanying drawings in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the illustrated embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.
A bottom view of an embodiment of an earth boring bit 30 is provided in
Aligning the ridges as described herein opens the insert face towards grooves or open space on the cone surface. As the insert penetrates the displaced material, the material is mechanically pushed into the open space and not trapped between adjacent inserts. The material trapped between conventional inserts, such as axially aligned chisels, may cause balling in shale thereby impeding its penetration rate. The axially and circumferentially aligned pyramid inserts also have a more streamlined shape allowing them to better withstand the sliding induced by cone offset and non-true-rolling cone geometry. Additionally, durability is enhanced with the disclosed cutting structure. Optionally, this advantageous result of the pyramid shape may be enhanced by strategically placed grooving between inserts to further enhance material flow. Moreover, inserts disposed proximate to the heel area may comprise a three sided pyramid due to the difficulty of displacement of material toward the gage of the bit.
A schematic drawing of a side view of an embodiment of a cone cutter 32 a is provided in
Alternative insert embodiments are provided in
The insert 87 in
It is to be understood that the invention is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. For example, the scope of this disclosure includes roller cone bits having different numbers of roller cones as well as inserts comprising pyramids having other than four sides. Additionally, the ridges' intersection is not limited to the embodiments disclosed, but can include intersections on the insert having a large range of radii, including an intersection forming a point on the insert crest. In the drawings and specification, there have been disclosed illustrative embodiments of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation. Accordingly, the invention is therefore to be limited only by the scope of the appended claims.