Rotary drill bit with wiper blade
US 3126066 A
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Description (OCR text may contain errors)
March 24, 1964 E. B. WILLIAMS, JR ROTARY DRILL BIT WITH WIPER BLADE Filed Deo. 5, 1960 Mdm/fm A TTNEX United States Patent Glice 3,126,066 ROTARY DRILL BIT WITH WIPER BLADE Edward B. Williams, Jr., Greenville, Tex., assign'or of one-third to Edward B. Williams III, one-third to Joseph W. Williams, and one-third to David B. Williams,
Filed Dec. 5, 1960, Ser. No. 73,898 2 Claims. (Cl. 17E-336) This invention relates to drill bits for rotary drilling of bore holes into earth formations, and particularly to drill bits of the type having toothed cutters for cutting through the various formations encountered in drilling such bore holes.
The cutters of this type of drill bit are usually arranged to roll in paths concentrically with the rotary axis of the drill stem, so that all of the cutters are used to cut the full gauge of the bore hole, consequently one cutter rolls over the same circular path as a preceding cutter. The result is that the teeth of one cutter must act on the formation through the cuttings produced by the other cutters. Usually the bodies of the drill bits are equipped with ports to discharge one or more jets of drilling fluid in contact with the bottom of the hole, which are supposed to clean the cuttings from under the cutters and carry the cuttings upwardly within the bore hole, however, such jets are not ecient because it is diflicult to direct te jets at angles to clean the bottom of the bore hole and have sufficient upflow velocity to carry the cuttings therewith. This is particularly true in slim hole drilling because the jets are almost vertical and in opposition to the upward flow. It is obvious that such conditions are not conducive to satisfactory removal of the cuttings, and the cuttings accumulate in the bottom of the hole, so that the cutters continue to rotate on the accumulated cuttings and sludge.
Therefore, the principal object of the present invention is to eliminate these diliculties and to maintain a clean hole by providing the drill bit with a wiper blade that has a cutting edge movable over the bottom of the hole for scraping up the cuttings, thereby leaving a clean bottorn hole surface on which the roller cutters will act with greater eiciency.
It is also an object of the invention to provide the wiper blade with means for discharging a high velocity jet of drilling fluid across the axis of rotation in a generally radial direction in sweeping contact with the cuttings as they accumulate in front of the wiper blade, to wash them through space between the cutters and upwardly of the wall of the bore hole with a minimum of interference by the cutters as the bit is rotated within the bore hole.
Another object of the invention is to provide the drill bit with one or more upwardly directed jets to induce and maintain hign velocity upward flow of the drilling iluid to carry the cuttings therewith to the top of the bore hole.
It is a further object of the invention to locate the cutters on the body of the drill bit so that they gyrate or roll in paths about the rotary axis of the drill stem, and to utilize the wiper blade in cooperation with the cutters for maintaining the gauge and straightness of the bore hole although the wiper blade makes a circular path of less diameter than the cutters.
A further object of the invention is to provide a bit with rotary cutters in a wiper blade that may be safely and easily run through a bore hole without damage to the cutters, and which because of the arrangement of the cutters and wiper blade may be run through bore holes and casings of smaller diameter than the size to be cut by the bit, as when continuing the drilling of a larger sized hole to greater depths or when reaming portions of a bore hole.
In accomplishing these and other objects of the invention as hereinafter pointed out, I have provided im- 3,126,066 Patented Mar. Z4, 1964 proved structure, the preferred form of which is illustrated in the accompanying drawings, wherein:
FIG. 1 is a vertical section through the bottom end of a bore hole and showing a drill bit therein which embodies the features of the present invention, the section being taken on the line 1 1 of FIG. 2 and looking in the direction of the arrows.
FIG. 2 is a cross section through the bore hole and showing the drill bit in end view, the section being taken on the line 2-2 FIG. l and looking upwardly as indicated by the arrows.
FIG. 3 is a cross section on the line 3-3 of FIG. 1.
FIG. 4 is a perspective View of the section of the drill bit that carries the wiper blade.
Referring more in detail to the drawings:`
1 designates a drill bit constructed in'accordance with the present invention to drill earth formations 2, as in drilling a bore hole 3 from the earths surface to substantial depths. The drill bit 1 includes a body portion 4, preferably composed of sector shaped sections 5, 6 and 7, suitably connected together, as, for example, by welds 8 (FIG. 3). The body of the drill bit includes an externally threaded pin 9 adapted to be connected to a drilling stern 16. The drilling stem is made up of a plurality of interconnected stands of drill pipe as in usual practice, and is rotated by rotary mechanism (not shown) at the top of the bore hole. The pin 9 is concentric with the rotary axis 1-1 of the drill stem and forms, with the body 4, an annular shoulder 12.
In the illustrated instances, the body member of the bit comprises three sector-shaped sections, designated 5, `6 and 7, meeting at the axis of rotation 11. The sections 5 and 6 are provided With a depending arm 13 and 14, re. spectively, with the vertical median lines thereof arranged substantially apart. In the present instance, the outer faces 15 of the arms are formed transversely thereof on arcs having their center of curvature on the rotary axis 11. The side made up of the section 7 has a depending wiper blade I16 with an outer face 16 formed on an arc of lesser radius and having an axial center offset from the axis of rotation on the side from said axis nearest the depending arms 13 and 14, whereby the radii of the outer faces of the arms are substantially the same, so that the bit may pass through a cased portion of a bore hole of less diameter than the drilling diameter of` the fbit.
When the drill stem 10 is located concentrically with the bore hole 3, the depending arms 13 and 14 of the sections 5 and 6 are close to the wall of the borehole, but the outer arcuate face of the wiper blade is spaced from the wall of the bore hole to provide an upllow passageway 17 therebetween of generally crescent shaped cross section. The inner or facing sides 18 of the -arms 13 and 14 are generally fiat and diverge outwardly and downwardly to provide backing for the respective cutters 19 and 20 that are rotatable on spindles 21 that extend downwardly and inwardly fromeach of the inner side` faces 18.
The cutters 19 and 2o have generally conical bodies 22, with the peripheries thereof provided with teeth 23 and which are arranged in spaced apart circular series, with the circular series of teeth on each cutter oset from the circular series of teeth on the other cutter, so that theteeth of the cutters cooperate to act on the entire area of the bottom of the hole when the bit is rotated by the drilling stem. The conical body portions and teeth of the cutters may generally correspond with the body portions and teeth of conventional cutters. The spacing of the axes of the cutters 19 and 2l), together with the diameter of the cutters, is such that a space 24 is provided between the cutters opposite the wiper blade 16, for a purpose later described. i
The teeth 23 of the cutters 19 and 20 produce different patterns of cuts, so that the cuts produced by a tooth of the leading cutter 19 are out of registry with the cuts produced by the teeth of the trailing cutter 20. The cutters 19 and 20 cooperate to chip or cut away the bottom 24 of the bore hole 3 over which they are caused to revolve. As above described the diameter of the bit through the section 7 is less than the diameter of the bit that is transverse thereto, as will be noted in FIG. 3. lt is, therefore, obvious that the bit, being of less diameter on one side, may be shifted laterally from the axis 11 of the bore hole and raised and lowered through the bore hole 3 without contacting the teeth of the cutters with the wall of the bore hole. In this way, a free space is opened up aroundv the entire periphery of the bit, iconsequently the bit may be readily removed or lowered through a casing (not shown) or an upper portion of the bore hole that may be of smaller diameter than the diameter to be drilled.
The wiper yblade 2 has a generally ilat leading face 25 following the cutter 20 and preferably set parallel with the plane containing the axis of the cutter 19. The face 25 is thus at an angle to the direction of rotation. The lower end of the blade has an edge 26 provided by a bevel 27 on the face side 25 and on the outer-side by a curvature 28. The blade has a iiow passage 30 that slopes downwardly and slightly outwardly from an axial bore 31 in the pin 9 and has a terminal portion 30' that extends inwardly and downwardly at a rather iiat angle relatively with the bottom 24 of the bore hole to discharge a jet of drilling uid through a port 29 in the face 25 and across the bottom 24 of the hole 3 and directly through the space 24' between the cutters 19 and 20. The sections and `6 of the bit that carry the cutters 19 and 20 are provided with passageways 34 that connect the axial bore 31 with upper and outwardly extending discharge ports 35 through which streams of drilling fluid are discharged upwardly to promote upward flow of drilling uid and cuttings from the lower portion of the bore In assembling the bit at the factory, the cutters 19 and 20 are placed on the spindles 21 of the respective segmental sections 5 and 6 and the sections 5, 6 and 7 are brought together and welded, as indicated by the numeral 8.
In using the drill bit constructed and assembled as described, it is attached to the drill stern and the drill stem is lowered into the bore hole, in accordance with the usual practice of running in the drilling string. Since the overall diameter of the bit is less than the diameter of the hole, it may be passed through a cased upper portion of the bore hole without damage to the teeth of the bit. The bit may be used for deepening a hole to a larger diameter and successfully lowered to drilling position as long as the hole is no smaller than the overall diameter of the bit.
With the bit in drilling position on the bottom of the hole, a drilling -fluid is circulated under pressure downwardly through the drill stem 10 for return ow exteriorly of the drill pipe to the top of the bore hole. Upon starting rotation of the drilling stern, the cutters 19 and 20 will revolve on their spindles 21 and move in circular paths over the bottom of the hole, with the teeth of the cutters bearing into and chipping away the formation being drilled. The wiper blade 16 travels in a circular path and the angularly disposed edge 26 thereof scrapes the cuttings from the path of the rolling cutters and pushes the loosened cuttings thereahead. Simultaneously with rotation of the drill stem, a portion of the drilling iluid being circulated passes from the axial bore 31 through the passageway 30 and discharges from the terminal 30 thereof and through the port 29 of the scraper blade in a high pressure jet that is directed downwardly and radially from the face 25 and across the axis of rotation 11 to impinge against the bottom of the bore hole at a relatively fiat angle to sweep the cuttings gathered by the wiper blade through the space 24 between the cutters 19 and 20 to the wall of the bore hole, which diverts the iluid of the jet upwardly at the sides of the drill bit. During rotation of the bit, the jet maintains its substantially radial discharge and is gyrated about the rotary axis of the drill stem to present the force of the jet in progressive sweeping contact with the entire bottom of the hole upon each revolution of the drill stern. Thus the cuttings made by the teeth of the bit are positively swept from the bottom of the bore hole and upwardly with the diverted jet. Simultaneously, jets of drilling iluid are discharged through the upwardly directed ports 35 to maintain .the upward ilow at high velocity to assure elevation of the cuttings to the top of the bore hole. With this combination of wiper blade and jets, the teeth of the cutters rotate upon a clean bottom to effect a more rapid and eicient cutting of the formation.
What I claim and desire to secure by Letters Patent 1. A rotary drill bit for drilling a bore hole in earth formations and the like, including a body member having a drill stem connection by which the drill bit is connected with the drill stem when the bit is in use and which connection is provided with a bore through which drilling iiuid is supplied from the drill stem to Isaid body member during rotation of the drill bit, spaced apart arms depending from said body member at one side thereof, spindles having axes in planes substantially apart and extending inwardly and downwardly from said arms toward the axis of rot-ation, conical cutters rotatable on ysaid spindles and of a size to provide a space between said cutters, and a wiper blade extending downwardly from the opposite side of the body member and having a leading face substantially parallel with a plane containing the axis of the cutter following the Wiper blade and at an angle to the direction of rotation to scrape up cuttings made by the cutter in advance of said wiper blade, said wiper blade having a duct extending downwardly from said bore and having a terminal portion in registry with 4said space between the cutters for discharging a jet of drilling fluid across said axis of rotation and through said space between the cutters for discharging said cuttings gathered by the face of said wiper blade together with the cuttings produced by the cutter which follows the wiper blade. 2. A rotary drill bit for drilling a bore hole in earth formations and the like, including a body member having a drill stern connection by which the drill bit is connected with the drill stern when the bit is in use and which connection is provided with a bore through which drilling iiuid is supplied from the drill stem to said body member during rotation of the drill bit, said body member comprising three sector-shaped sections joining at the axis of rotation, arms depending from two of said sector-shaped sections and having outer arcuate faces of common center of curvature from said axis of rotation, spindles having axes in planes substantially 12()D apart and extending inwardly and downwardly from said arms, conical cutters rotatable on said spindles and of a size to provide a space between said cutters, and a wiper blade extending downwardly from the remaining sector-shaped section and having a leading inner face `substantially parallel with a plane containing the axis of the following cutter and at an angle to the direction of rotation to scrape up cuttings made by the cutter in advance thereof and having an outer face of a radius oiset from the axis of rotation on the side of said axis nearest the depending `arms whereby the drill bit may be lowered through a cased portion of the bore hole to drilling position,
said wiper blade having a duct extending downwardly from said bore and said duct having a terminal portion in directing registry with said space between the cutters for discharging a jet of drilling fluid across said axis of rotation for discharging said cuttings gathered by the face of said wiper blade through said space together with the cuttings produced by the cutter which follows the Wiper blade.
References Cited in the file of this patent UNITED STATES PATENTS