US2851253A - Drill bit - Google Patents

Description

Sept. 9, 1958 Filed April 27, 1954 E G. BOICE DRILL BIT 2 Sheets-Sheet l f/w/v 6. Bo/ce INVENTOR.

E. G. BOICE Sept. 9, 1958 DRILL BIT 2 Sheets-Sheet 2 Filed April 27, 1954 f/V/f) 6. Bo/ce v INVENTOR.

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ATTORNEYS United States Patent DRILL BIT Elvin G. Boice, Houston, Tex., assignor to Reed Roller Bit Company, Houston, Tex., a corporation of Texas Application April 27, 1954, Serial N0. 425,889

7 Claims. (Cl. 255-347) This invention relates generally to drill bits, and more particularly to bits for deepwell drilling.

One of the general objects of the invention is to provide a new and improved drill that will more efficiently drill hard and medium-hard formations.

Another object of the invention is to provide new and improved well drill rollers having the teeth thereon arranged to produce a more effective action in disintegrating material at the bottom of the well being drilled.

A further object is to provide a well drill roller having teeth 'theron which may be connected together by a web that extends radially beyond the teeth, to support and cooperate with the teeth during the drilling operation.

A further object is to provide a new and improved well drill roller wherein the teeth or cutting elements on the same roller may engage the formation simultaneously at diiferent levels, in order to facilitate the removal of particles of the formation at the bottom of the bore hole being drilled.

A further object is to provide a new and improved well drill roller having teeth thereon, and wherein, on the same roller, a cutting element extends radially beyond the teeth on the roller so that during the drilling operation the extended cutting element will cut a narrow circular groove in the formation at the bottom of a bore hole thereby reducing the lateral support of the formation circumscribed by the circular groove, thus facilitating the removal of particles of the formation by the well drill.

Another object is to provide a roller bit that will during the drilling operation cut a kerf in the gage portion of the bottom of the hole so that the formation within the area circumscribed by the kerf will not be supported by the surrounding formation and may be removed more readily.

Another object is to provide a new and improved well drill roller having a more effective form of cutting element to remove the formation from the outer gage portion of the bore hole being drilled.

Another object is to provide a new and improved roller having cutting elements arranged thereon to stabilize the roller during the drilling operation.

Other objects and advantages of the invention will become apparent from the following description and the accompanying drawings wherein are set forth by way of example certain embodiments of the invention.

Fig. l is a bottom plan view of a cross roller bit embodying the invention.

Fig. 2 is a side elevation view of the bit shown in Fig. 1.

Fig. 3 is a detail view of a side roller showing a circumferentially extending web on the gage cutting portion of the roller.

Fig. 4 is a fragmentary section view taken along line 4-4 of Fig. 3.

Fig. 5 is an isometric view of a cone bit embodying the invention.

Fig. 6 is a detail view of a portion of a side roller em- 2,851,253 Patented Sept. 9, 1958 bodying the invention showing the roller in operating position on the formation at the bottom of a bore hole.

Figs. 1 and 2 illustrate a cross roller bit employing a number of conventional parts and the new and improved rollers provided by the invention. In these figures, abit head 1 has the usual threadedshank 2 by which the bit may be attached to the lower end of a drill stem (not shown). Thehead 1 may have the usual dependinglegs 3, 4, 5 andbridge 6 to support the usual pins (not shown) upon which may be rotatably mounted the new and improvedcross rollers 7 and 8 andside rollers 9 and 10. Thecross rollers 7 and 8 each have a row of axially disposedteeth 11 thereon. The outer ends of theteeth 11 are connected together by a web or cuttingelement 12. This web extends radially beyond theteeth 11 as is clearly shown in Figs. 1 and 2.

Theside rollers 9 and 10 are similar to each other and to thecross rollers 7 and 8 in construction. Theside rollers 9 and 10 each have a row ofteeth 13. A web orcutting element 14 connects together theteeth 13 at the outer or gage cutting portion of therollers 9 and 10. Theweb 14 extends radially beyond theteeth 13 of theside rollers 9 and 10 to assist in cutting and maintaining the gage of the bore hole, and supports theteeth 13, during the operation of the bit.

In operation, a drill bit is attached to the lower end of a drill stem (not shown), and rotated upon the bottom of a bore hole. Thus the rollers are caused to rotate, and as weight is-applied to the bit by the weight of the drill stem, the teeth or cutting elements of the rollers will crush, chip or scrape the formation upon which the bit is rotated. The particles of formation thus dislodged will be carried out of the bore hole by drilling fluid which is pumped down through the drill stem and bit head, returning to the surface of the earth in the space between the drill stem and the wall of the bore hole being drilled.

One of the most important desired functions of theside rollers 9 and 10 is to cut and maintain the gage or diameter of the bore hole being drilled, so that succeeding drill bits, or other equipment, can be lowered to the bottom of the bore hole without having to ream down an undergage hole. The gage portion of the bore hole is diflicult to remove and maintain because the formation at the gage or outer portion of the bore hole is supported by the side wall of the hole thus making it more diflicult to dislodge, also, there is more material to be removed from the gage or outer portion of the bore hole because it is a greater distance from the center or the bore hole.

In my invention I provide more efiicient cutting ele ment arrangement to cut and maintain the gage of the bore hole by providing more material at the outer or gage cutting portions of theside rollers 9 and It) in the form of a radially extendedweb 14. Thisweb 14 cuts a narrow kerf in the formation thereby reducing the support of the formation circumscribed by the kerf making it easier to disintegrate and remove from the hole bottom by the drill bit.

Also thecross rollers 7 and 8 may be provided with webs to cut additional kerfs in the formation to permit easier removal thereof.

Also, thewebs 14 on theside rollers 9 and 10 and thewebs 12 on thecross rollers 7 and 8, rolling in kerfs in the hole bottom stabilize the rollers from moving in an outboard or inboard direction with respect to the drill bit axis of rotation, because the webs act as flanges tending to keep the rollers in their respective paths during the drilling operation.

Figs. 3 and 4 show in detail aside roller 9 of the type shown in Figs. 1 and 2, and previously described. Theroller 9 has a circumferential row ofteeth 13 and a. circumferentially extendingweb 14 connecting the outer ends of theteeth 13 together. Theweb 14 extends radialice 1y beyond theteeth 13 as is clearly shown in Figs. 3 and 4.

Fig. 5 shows a cone bitemploying the new and improved substantiallyconical rollers 15. Theroller 15 has circumferentially disposed rows ofteeth 16 and a circumferentially extending web or cuttingelement 17 connecting the ends ofteeth 16 in the same row together. Theweb 17 extends radially of the roller beyond theteeth 16. Theweb 17 thus serves to support the teeth, and to cut a narrow kerf in the formation during the drilling operation.

Fig. 6 is a typical illustration of the action of the new and improved roller upon the formation. A portion of theside roller 9 havingteeth 13 andweb 14 is shown in operating position on the bottom of a bore hole. Theweb 14 is shown producing akerf 18 in the formation A, and theteeth 13 are shown operating on the formation within the area defined by thekerf 18 but at a different level. The web 14- serves to cut and maintain the bore of the hole B.

In the actual use of a well drill employing the new and improved rollers, I have found that the cutting elements on the roller drill faster and tend to retain their original configuration and relationship. Even when the cutting elements are approximately half-worn away, the web still extends radially beyond the other cutting elements on the same roller.

It will be understood that the invention is not limited to the particular embodiments herein shown and described. Various changes within the scope of the following claims will be apparent to those skilled in the art.

Having disclosed and described my invention, I claim:

1. A roller bit having a head, a substantially conical roller cutter rotatably mounted in said head, the axis of rotation of said cutter extending downwardly and inwardly substantially toward the longitudinal axis of said head, the base end of said cutter being outermost, said cutter having a circumferentially extending web at its base end to define the wall of the hole by cutting a kerf in the gage portion of the bottom of the hole and teeth connected to said web and extending inwardly longitudinally of said cutter to operate upon the formation at the bottom of the hole within the area circumscribed by said kerf said web extending radially beyond the cutting edge of the teeth.

2. A roller bit having a head, a roller cutter rotatably mounted in said head, the axis of rotation of said cutter extending downwardly and inwardly substantially toward the longitudinal axis of said head, said cutter having a circumferentially extending web at its outermost end to define the wall of the hole by cutting a kerf in the gage portion of the bottom of the hole and teeth connected to said web and extending inwardly longitudinally of said cutter to operate upon the formation at the bottom of the hole within the area circumscribed by said kerf said web extending radially beyond the cutting edge of the teeth.

3. A roller bit having a head, a roller cutter rotatably mounted in said head, the axis of rotation of said cutter extending downwardly and inwardly substantially toward the longitudinal axis of said head, said cutter having a circumferentially extending web at its outermost end to cut a kerf in the gage portion of the bottom of the hole and teeth extending inwardly longitudinally of said cutter to operate upon the formation at the bottom of the hole within the area circumscribed by said cutter said web extending radially beyond the cutting edge of said teeth.

4. A roller bit having a head, a roller cutter rotatably mounted in said head, the axis of rotation of said cutter extending downwardly and inwardly substantially toward the longitudinal axis of said head, said cutter having circumferentially extending cutting means at its outermost end to cut a kerf in the gage portion of the bottom of the hole and means to operate upon the formation at the bottom of the hole Within the area circumscribed by said kerf said first mentioned means extending radially beyond the cutting edge of said second mentioned means.

5. A drill bit comprising a bit head, cross rollers and gauge rollers rotatively mounted in the lower portion thereof, each of said gauge rollers having teeth thereon extending longitudinally thereof, and having an annular web at its base and connecting the said teeth together, said web extending radially beyond the cutting edge of said teeth to cut a kerf in the gauge portion of the bottom of the hole.

6. A roller bit comprising a head, a roller rotatively supported in said head, the said roller having a row of axially disposed teeth thereon, an annular web connecting the outer ends of said teeth together at the outermost end of said roller, the said web extending radially "substantially axially extending teeth thereon, that imbeyond the cutting edge of said teeth to cut a kerf in the gauge portion of the bottom of the hole.

7. In a roller bit comprising a head, a roller cutter rotatively supported in said head, the said cutter having References Cited in the file of this patent UNITED STATES PATENTS 1,143,275 Hughes June 15, 1915 1,905,165 Fletcher Apr. 25, 1933 2,184,066 Zublin Dec. 19, 1939 2,248,340 Catland July 8, 1941 2,527,838 Morlan et al. Oct. 31, 1950 2,660,405 Scott et al Nov. 24, 1953

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