|Publication number||US3140748 A|
|Publication date||Jul 14, 1964|
|Filing date||May 16, 1963|
|Priority date||May 16, 1963|
|Publication number||US 3140748 A, US 3140748A, US-A-3140748, US3140748 A, US3140748A|
|Inventors||Engle Edgar W, Foster Jr James L|
|Original Assignee||Kennametal Inc|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (6), Referenced by (22), Classifications (9)|
|External Links: USPTO, USPTO Assignment, Espacenet|
y 14, 1964 E. w. ENGLE ETAL EARTH BORING DRILL BIT 3 S eats-Sheet 1 INVENTORS. EDGAR IV. ENGLE JAMES L FOSTER, JR.
Filed May 16, less A TTOR/VE V5 uly 14, 1964 E. w. ENGLE ETAL EARTH BORING DRILL BIT 3 Sheets-Sheet 2 Filed May 16, 1965 INVENTORS. EDGAR M ENGLE JAMES L. F057ER,JR.
J1l1y'14, 1964 E. w. ENGLE ETAL I 3,140,743
EARTH BORING DRILL BIT Filed May 16, 1963 INVENTORS. EDGAR 11 54/045 BY .uuss 4. FOSTE/LJR.
United States Patent 3,140,748 EARTH EORING DRILL BIT Edgar W. Eagle and James L. Foster, 3n, Laughlintown,
Pa, assignors to Kennainetal Inc., Latrobe, Pa., a corporation of Pennsylvania Filed May 16, 1963, Ser. No. 280,969 6 Claims. (til. 175410) This invention relates to an earth boring drill bit of the rigid bearingless type, known as a drag bit. Although the emphasis in this application is on the use of such a bit in drilling through earth formations for oil, gas, and the like, it is to be understood that the invention is also useful in other earth boring applications, including mining and quarrying.
Oil well drill bits are subjected to a great variety of operating conditions. The formations they are called upon to penetrate, the type of rigs used to drive them, the nature of the various components in the drill string, the hydraulic system used, and the applied loads and rotary speeds, all vary widely. The interaction of these variables affects bit life, measured either in hours of drilling operation or in feet of earth penetration, and it also affects the rate of peneration and the ability of the bit to drill through hard rock formations.
Drilling bits that are characterized by long life under the above operating conditions, and that are also characterized by rapid penetration in a variety of formations from soft to hard, by low frequency of pulls, by maintenance of substantially full hole gauge and by limitation of hole deviation within allowable limits, are very valuable to the petroleum industry. In addition, a satisfactory bit should be self-sharpening; and it should also have a certain geometry to penetrate rapidly through various formations. the bit, it should be retained as the bit wears in use. In some cases, however, the desired bit geometry is created only as the bit wears in use and, once created, should be retained during further use.
It is accordingly among the objects of this invention to provide a rotatable drag bit that will have the desirable characteristics mentioned above, including the capability of drilling in hard formations at a faster rate over longer periods of time than is obtainable with conventional bits, that will maintain a substantially full gauge hole in hard and abrasive rock formations, that will be self-sharpening, and that will have a wear pattern in use that will retain or create a desirable geometry for the bit.
The foregoing and other objects of the invention will be apparent from the following description of a preferred embodiment, in connection with the accompanying drawings, in which FIG. 1 is an end view of a drag bit made in accordance with this invention;
FIG. 2 is a side elevation of the bit of FIG. 1;
FIG. 3 is a front elevation of this same bit;
FIG. 4 is a fragmentary section along the line IVIV of FIG. 1;
FIG. 5 is an end view of a modified form of drag bit;
FIG. 6 is a front elevation of the bit of FIG. 5;
FIG. 7 is a side elevation of the same bit;
FIG. 8 is a fragmentary section along the line VIII-VIII of FIG. 5;
FIG. 9 is a fragmentary end view of a further modified form of drag bit; and
FIG. 10 is a section along the line XX of FIG. 9.
The drill bit of the present invention is adapted to be rotated about its longitudinal axis and includes a body that can be attached to the drill string by conventional means and a plurality of drag bit wings supported by the body. Each wing extends radially beyond the body to provide a hole-gauging face substantially in the form of Where this geometry is initially present in 3,146,748 Patented July 14, 1964 "ice a portion of a cylindrical surface that subtends, for the reasons hereinafter discussed, a substantial circumferential arc. Each wing also extends axially ahead of the body to provide an end drilling face having the general form of a sector of an annulus. Lastly, each wing has an extended, generally plane, forward face, on which is mounted a layer of cemented tungsten carbide, or other suitable hard material, which not only protects the forward face from wear (for example, from erosion by drilling muds), but also provides extremely hard cutting edges at the junctions of the forward face with the ganging and end faces. In addition, cemented tungsten carbide inserts are embedded in each wing behind its forward face, with portions of the inserts exposed on the gauging and end faces. These inserts serve the important purpose of limiting the wear of the wing material that directly supports the cutting edges on the forward face, thereby to assure that those cutting edges will be backed up by adequate material as the bit is used and so prevent their breakage and prolong their useful life. Moreover, the exposed portions of the inserts on the gauging and end faces supplement the cutting action of the forward face cutting edges and, if necessary, can perform that function alone; they have also other useful functions to be described herein.
Referring to the drawings, the bit of this invention includes a body 1 of steel or other suitably strong material, which is adapted to be attached by conventional means (not shown) to the end of a rotating drill string. Formed integrally with the body, or secured thereto by any suitable means, are a plurality of drag bit wings 2 which are substantially symmetrically disposed about the longitudinal axis of the bit and are made of steel or other suitably strong material. These wings extend radially beyond the body to form a hole-gauging face 3 that is substantially a portion of a cylindrical surface generated by a line rotated about the longitudinal axis of the bit, or about a line parallel to that axis. This face extends circumferentially over a substantial are, preferably of at least 10 sufficient to provide a strong base and support for the cutting elements. The exact arcuate extent of the gauging face 3 will depend in part on the diameter of the drill (being greater for smaller diameter drills) and on the types of formations to be drilled. Each wing also extends axially ahead of the body to form an end drilling surface 4, which is generally in the form of a sector of an annulus, of which the outer arcuate edge 6 coincides with an edge of the cylindrical gauging face and the central inner edge 7 is formed by the inner arc of the annulus. Each wing also has a forward face 8 of extended area and of generally planar form. This face may, if desired, be disposed in two planes, as shown in FIGS. 1-3, or in a single plane, as shown in FIGS. 4-7, these planes being generally parallel or substantially parallel to the longitudinal axis of the bit.
Each forward face 8 is substantially covered by a layer of a suitable hard alloy, preferably in the form of a plurality of plates 9 of cemented tungsten carbide. These plates may be brazed to the face 8; or, under certain conditions, a layer of other suitable hard material can be puddled or welded on the face. The plates 9 are preferably of simple geometrical form, such as squares or rectangles, to provide straight end cutting edges 11 and side cutting edges 12. The thickness of the plates will vary, depending up on the size of the bit, the formations to be penetrated, etc. The plates also serve to protect the face from erosion by abrasive particles entrained in the drilling fluid, this fluid being pumped through openings 13 of nozzles 14, which are preferably made of cemented tungsten carbide.
In the wing material behind the forward face are embedded a plurality of cemented tungsten carbide inserts 16, which are so disposed that they tend to minimize wear of the wing material that supports the cutting edges of the carbide plates on the forward face. These inserts may take a variety of forms, such as cylindrical rods or substantially rectangular right prisms, and may be embedded with their long axes either parallel or inclined to the longitudinal axis of the bit, or extending radially of the bit. Further considerations that govern the location of these embedded inserts include the promotion and maintenance of a desired bit geometry during prolonged drilling, such as, for example, the promotion and maintenance of concentric arcuate grooves in the drilling face of the bit, these fingering grooves helping to minimize undesirable gyrations of the bit. For example, in FIGS. 1-4, one group of inserts 17 is in the form of cylindrical plugs of cemented tungsten carbide embedded in the end drilling face and extending parallel to the axis of the bit, and a second group of inserts 18 is in the form of substantially right rectangular prisms embedded radially in the gauging face and extending in a single row parallel to the axis of the bit. A third group of inserts 19 is in the form of cylindrical rods that lie in a second longitudinal plane disposed at an angle to the plane of the first two groups of inserts, and each insert of the third group is disposed at an angle of approximately 45 to the axis of the bit. The exposed portions of these last inserts are confined to the gauging face and to the intersection of that face and the end face, but additional inserts may be inserted in this same plane in the end face, if desired, as shown by the broken line elements 21 in FIGS. 1 and 4. There is also shown in FIG. 4, by the broken line 22, an approximate typical profile or contour of the end face after the bit has been used for a certain period of time. A second contour line 23 shows a typical bit profile after the bit has been used for a still longer time. As these profile lines indicate, the end of the bit gradually assumes a somewhat conical shape, and there is a tendency for the wing material between the embedded inserts to wear faster than the inserts themselves to produce a desirable fingering configuration. The side cutting edges of the forward face may be reinforced by an additional group of carbide inserts 24, which are disposed directly behind and in supporting contact with the edge forming plates 9 of the forward face. The exposed portions of these inserts are contoured to conform to the surface of the gauging face.
In the modified form of bit shown in FIGS. -8, all of the embedded carbide inserts in the wings are in the form of spaced cylindrical rods, which are disposed in two main groups. Those inserts 26 on the end face and on the adjacent portion of the gauging face are set at an angle of 45 to the axis of the bit, with the inserts exposed on the end face lying in concentric circles about the bit axis and the inserts exposed on the gauging face lying in horizontal and vertical rows. However, on that portion of the gauging face that is remote from the end face, the inserts 27 lie in horizontally staggered rows and extend radially of the wing and substantially normal to the axis of the bit. The insert arrangement in the first group of inserts 26 tends to promote the development of the fingering or grooving contour that helps to keep the bit properly aligned. That of the second group of inserts 27, where the inserts are staggered horizontally and the space between any two inserts in a vertical row is preferably less than the diameter of the insert in an adjacent vertical row, tends to avoid the grooving or fingering configurations that is desirable elsewhere and provides a better and more lasting gauging action to maintain hole size during drilling.
In FIGS. 9 and 10, the cemented tungsten carbide inserts are in the general form of cylindrical rods of different diameters, all of which are oriented parallel to the bit axis. The larger diameter inserts 31 are embedded in slots in the gauging face, and each extends for the full length of that face and has its exposed portion contoured to conform to the surface of that face. Inserts 31 supplement the gauging or side cutting edge 12 of the forward face, as well as the radially outer portion of the end cutting edge 11 of that face. The smaller diameter inserts 32, which are disposed on a radial line inward of one of the inserts 31, supplement the end cutting edge 11 of the forward face.
It will be apparent to those skilled in the art that it is possible to use still other arrangements and dispositions of the cemented tungsten carbide inserts, it being the function of those inserts, (1) to limit wear and erosion of the end and gauging faces of the bit, so that the cemented tungsten carbide inserts on the forward faces will have an adequate depth of wing material to support them and (2) to act as supplemental cutting edges or points that cooperate wtih the cutting action of the forward face edges and, in the event those edges fail, take over their function. In addition, the inserts in the end face have a further important function. In deep well drilling, the clasticity of the drill string creates considerable percussive interaction between the end of the drill bit and the formation being drilled. Such percussive action permits the eX- posed ends of the carbide inserts to disintegrate the rock, without injury to the carbide inserts, because they are all well embedded in a mass of strong material that gives them adequate support.
Among the advantages of using the heavy wing structure and the cemented tungsten carbide inserts, mounted in slots, recesses, or holes in the wings behind the forward faces, as herein described, is that the useful life of carbide cutting edges on the forward faces is greatly increased, because such inserts not only limit wear of the material supporting those edges, but also share in the cutting action. The inserts also are capable of taking over the function of the carbide cutting edges on the forward faces, in the event those edges fail. It has been found that cemented carbide cutting edges, if adequately supported in this way, can be held in place without failure of the carbide itself or of the carbide to steel bond when subjected to loads that would cause such failure if the inserts were not present.
Another advantage of the present invention is that the embedded carbide elements in the wings may be so disposed that they cause the desired bit geometry to be generated or retained as wear occurs, as, for example, a fingering configuration may be generated to reduce bit gyration, as Well as to assist in gaining a greater rate of penetration.
According to the provisions of the patent statutes, we have explained the principle of our invention and have illustrated and described what we now consider to represent its best embodiment. However, We desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.
1. A drilling bit of the drag bit type adapted to be rotated about its longitudinal axis, the bit comprising: a body, a plurality of wings supported by the body, each wing extending radially beyond the body to provide a holegauging face in the form of a portion of a cylindrical surface that subtends a substantial circumferential arc, each wing also extending axially ahead of the body to provide an end drilling face in the form generally of a sector of an annulus, and each wing also having an extended forward face of generally planar form, a layer of hard alloy material secured to each forward face to provide hard cutting edges at the junctions of that face with the gauging and drilling faces, and cemented tungsten carbide inserts embedded in each wing behind the forward face with portions of the inserts exposed on the gauging and drilling faces for limiting wear of the wing material supporting the cutting edges of the hard alloy material on the forward face and for supplementing the cutting action of those edges.
2. Apparatus according to claim 1, in which the circum- O ferential arc subtended by the gauging face of each Wing is at least 10.
3. Apparatus according to claim 1, in which the layer of hard alloy material secured to each forward face is in the form of a plurality of plates of cemented tungsten carbide, the plates being arranged in a regular tessellation substantially covering said face.
4. Apparatus according to claim 1, in which the portions of the inserts exposed on the end drilling face are radially spaced to provide preferential arcuate grooving of the end face for increasing penetration rate and for limiting gyration of the bit during drilling operations.
5. Apparatus according to claim 1, in Which the portions of the inserts exposed on the gauging face adjacent the end face are axially spaced to provide preferential grooving of that part of the gauging face for increasing penetration rate and for limiting gyration of the bit during drilling operations.
6. Apparatus according to claim 5, in which portions of the inserts exposed in the gauging face remote from the end face are disposed in a staggered array to prevent preferential grooving of that part of the gauging face during drilling operations.
References Cited in the file of this patent UNITED STATES PATENTS 1,923,487 Howard Aug. 22, 1933 1,923,488 Howard Aug. 22, 1933 1,978,084 Howard Oct. 23, 1934 2,693,938 Roberts Nov. 9, 1954 3,106,973 Christensen Oct. 15, 1963 FOREIGN PATENTS 1,228,941 France Mar. 21, 1960
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US1923487 *||Oct 5, 1931||Aug 22, 1933||Globe Oil Tools Co||Well drilling bit|
|US1923488 *||Oct 5, 1931||Aug 22, 1933||Globe Oil Tools Co||Well bit|
|US1978084 *||Feb 5, 1932||Oct 23, 1934||Globe Oil Tools Co||Well drilling bit|
|US2693938 *||Aug 1, 1952||Nov 9, 1954||Roberts Harry E||Drilling bit|
|US3106973 *||Sep 26, 1960||Oct 15, 1963||Christensen Diamond Prod Co||Rotary drill bits|
|FR1228941A *||Title not available|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US3301339 *||Jun 19, 1964||Jan 31, 1967||Exxon Production Research Co||Drill bit with wear resistant material on blade|
|US3952815 *||Mar 24, 1975||Apr 27, 1976||Dresser Industries, Inc.||Land erosion protection on a rock cutter|
|US4185707 *||Apr 10, 1978||Jan 29, 1980||Wilson Alvin K||Auger construction|
|US4262761 *||Oct 5, 1979||Apr 21, 1981||Dresser Industries, Inc.||Long-life milled tooth cutting structure|
|US4431065 *||Feb 26, 1982||Feb 14, 1984||Smith International, Inc.||Underreamer|
|US4616719 *||Sep 26, 1983||Oct 14, 1986||Dismukes Newton B||Casing lateral wells|
|US5025873 *||Sep 29, 1989||Jun 25, 1991||Baker Hughes Incorporated||Self-renewing multi-element cutting structure for rotary drag bit|
|US5103922 *||Oct 30, 1990||Apr 14, 1992||Smith International, Inc.||Fishtail expendable diamond drag bit|
|US5456312 *||Oct 17, 1994||Oct 10, 1995||Baker Hughes Incorporated||Downhole milling tool|
|US5810079 *||Oct 10, 1995||Sep 22, 1998||Baker Hughes Incorporated||Downhole milling tool|
|US5899268 *||Oct 28, 1997||May 4, 1999||Baker Hughes Incorporated||Downhole milling tool|
|US7228922||Jun 8, 2004||Jun 12, 2007||Devall Donald L||Drill bit|
|US7455126||May 25, 2004||Nov 25, 2008||Shell Oil Company||Percussive drill bit, drilling system comprising such a drill bit and method of drilling a bore hole|
|US7513319||Jun 11, 2007||Apr 7, 2009||Devall Donald L||Reamer bit|
|US7546888 *||Jun 11, 2004||Jun 16, 2009||Shell Oil Company||Percussive drill bit|
|US7726419||May 25, 2004||Jun 1, 2010||Shell Oil Company||Drill bit, system, and method for drilling a borehole in an earth formation|
|US8020641||Oct 13, 2008||Sep 20, 2011||Baker Hughes Incorporated||Drill bit with continuously sharp edge cutting elements|
|US8720609||Oct 13, 2008||May 13, 2014||Baker Hughes Incorporated||Drill bit with continuously sharp edge cutting elements|
|US20060131075 *||Jun 11, 2004||Jun 22, 2006||Cruz Antonio Maria Guimaraes L||Percussive drill bit|
|US20060249309 *||May 25, 2004||Nov 9, 2006||Cruz Antonio Maria Guimaraes L||Drill bit, system, and method for drilling a borehole in an earth formation|
|US20070039761 *||May 25, 2004||Feb 22, 2007||Cruz Antonio Mari G L||Percussive drill bit, drilling system comprising such a drill bit and method of drilling a bore hole|
|EP0239328A2 *||Mar 20, 1987||Sep 30, 1987||Smith International, Inc.||Drill bits|
|U.S. Classification||175/426, 175/421|
|International Classification||E21B10/46, E21B10/56, E21B10/54|
|Cooperative Classification||E21B10/54, E21B10/56|
|European Classification||E21B10/56, E21B10/54|