US3191698A

US3191698A - Blade-type drill bit

Info

Publication number: US3191698A
Application number: US195595A
Authority: US
Inventors: Short Lot William
Original assignee: Drilling and Service Inc
Current assignee: Drilling and Service Inc
Priority date: 1962-05-17
Filing date: 1962-05-17
Publication date: 1965-06-29
Anticipated expiration: 1982-06-29

Description

June 29, 1965 L. w. SHORT 3,191,698

BLADE-TYPE DRILL BIT Filed May 17. 1962 ORNE YS United States Patent 3,191,698 BLADE-TYPE DRILL BIT Lot William Short, Dallas, Tex., assignor to Drilling & Service, Inc., Dallas, Tex., a corporation of Texas Filed May 17, 1962, Ser. No. 195,595 19 (Zlaims. (ill. 175-33) This invention relates to a blade-type drill .bit and more particularly to a drill bit using hard, abrading elements, such as diamonds, arranged along generally radially extending blade-like projecting ribs forming the cutting edges of the bit.

The present invention constitutes a modification of the bit described and claimed in my United States Letters Patent No. 2,990,897, issued July 4, 1961, and possesses certain advantages over the drill bit of that patent in the drilling of bore holes in earth formations, particularly with respect to a more economical use of diamonds, or other hard abrasive abrading elements. In accordance with my present invention, I preferably employ the generally triangular configuration, when viewed in bottom plan view, that is shown in my aforesaid patent, but instead of providing abrading particles in closely spaced relationship embedded in .the lower working face .and lateral reaming faces substantially throughout their entire area, I embed, prefera bly, a single row of diamonds along the leading, or cut ting, edge of each of a plurality of blade-like projecting ribs that extend radially outwardly from near the center I of the lower face of the bit and upwardly along the lateral, segmental-cylindrical, reaming faces of the bit. The projecting blade-like ribs are formed between the lower surface of the .bit and the generally radially extending water grooves that also extend upwardly along the lateral reaming faces of the bit. The lower working face of the bit on the other, or trailing, edge of each of the radially extending grooves is slightly offset axially upwardly and/ or inwardly, and is generally flattened to provide an abutment or bumper that is free of abrading particles. The edge of the abutment at each groove will be referred to as the trailing edge of the abutment.

Additionally, provision is made for conducting a drilling fluid under high pressure into each of the radially extending grooves intermediate the length thereof, and the grooves are preferably restricted in cross-section outwardly toward the periphery of the lower working face to insure a high velocity flow of drilling fluid over and around the abrading elements to cool the same and upwardly along the extensions of said grooves in the lateral faces of the bit to carry away cuttings and loose material formed during the drilling operation. For the purpose of removing larger cuttings, a groove of greater crosssectional area than the grooves previously mentioned extends from a closed recess near the center of the working face of the bit outwardly to and through a non-reaming facet that lies wholly within the lateral periphery of the bit generated by the segmental-cylindrical faces thereof.

It is therefore an important object of this invention to provide a drill bit of a blade-type construction that makes a more economical use of the diamonds, or other abrading elements, and that possesses novel operational advantages in the drilling of bore holes in certain types of earth formations.

It is a further object of this invention to provide a drill bit of improved construction in which there is a more eflicient utilization in operation of high velocity streams of drilling fluid in the cooling of the abrading elements and in the removal of the cuttings and loose particles of earth formation formed or encountered in drilling.

It is a further object of this invention to provide, in a drill hit, an arrangement of generally radially extending water grooves, each forming with the lower working face of the bit a blade-like projecting rib that constitutes the leading edge and that is set with a row of abrading elements along its length, with the opposite or trailing edge of the respective grooves slightly offset axially upwardly and/or inwardly, and with the lower face of the bit adjacent such trailing edge providing a generally flattened abutment or bumper that cooperates by contact with the bottom of the bore hole to cause a high velocity flow of the drilling fluid over the leading edge of the corresponding blade to cool and free the abrading elements set therein for their cutting action.

It is a further important object of this invention to provide a blade-type of drill bit the lower working face of which is provided near its center with a recess from which extend water grooves that are of restricted cross-sectional area toward the periphery of the Working face and that are supplied with a drilling fluid intermediate their lengths for high velocity flow over the abrading elements that are set in the leading blade-type edges of such grooves.

Other objects, features and advantages of this invention will become apparent to one skilled in the art from the following description of the embodiments of the invention illustrated in the accompanying drawings, in which:

FIGURE 1 is a bottom plan view of a drill bit embodying the features of my invention;

FIGURE 2 is a sectional view taken substantially along the line II-II of FIGURE 1;

FIGURE 3 is a sectional view taken substantially along the broken line III-III of FIGURE 2; and

FIGURE 4 is a reduced, fragmentary elevational View taken substantially along the line IV-IV of FIGURE 1.

As shown on the drawings:

The drill bit illustrated in the drawings is one adapted to be attached to the lower end of a rotary drill stem in the drilling of oil wells and the like, wherein the drill stem (not shown) is rotated by a rotary table (not shown) and wherein a drilling fluid, such as any of those commonly used for the purpose, is circulated down through the drill stem and discharged through the lower working end of the drill bit. The drilling fluid is for the purpose of cooling the abrading elements of the bit and of carrying away from the bottom of the bore hole the particles of earth formation generated by the abrading action of the drill bit or otherwise present in the bottom of the hole. As is well understood, the drilling fluid is usually a water suspension of a :bentonite clay or the like, and is pumped down to the drill bit .under considerable pressure. As will later be explained, the particular arrangement of fluid discharge bores and water grooves in the bit of my invention, in combination with the configuration of the lower Working face of the bit and the constriction of the water grooves toward the periphery of such Working face results in a higher velocity flow of drilling fluid over and around the abrading elements during their cutting action than has heretofore been usually the case.

With more specific reference to the drawings, the reference numeral 10 indicates generally a drill bit of my invention, provided at its upper end with a shank 11 having an axially extending recess 12 that is open at the top for receiving the drilling fluid from the drill stern and that is counterbored at the bottom, as at 13. The shank 11 is thus hollow, and is provided with an externally tapered, threaded portion 14 for attachment to the drill stem. The body of the bit, indicated at 15, is carried by the shank 11 at the lower end thereof and is usually integral therewith. Said body 15 is preferably of a generally triangularly shaped configuration when viewed in bottom plan, as in FIGURE 1.

As there shown, the body portion 15 comprises three segmental-cylindrical lateral faces 16, 16a and 16b, between which extend

non-reaming facets

17, 17a and 17b, each of which is of greater peripheral extent than any of the segmental-cylindrical reaming faces 1%, 16:: Or 16b,

enemas and each of which lies wholly within the cylinder generated by said segmental-cylindrical lateral faces. While the

non-reaming facets

17, 17a and 17b are illustrated as being substantially fiat in FIG. 1, they may be arcuate, either convexly or concavely, so long as they lie wholly Within the generated cylinder. As shown in FIG. 4, the non-reaming facets, such as 1711-, extend laterally upwardly to near the top of the enlarged body portion of the bit, while the reaming lateral faces, such as 16 and 16b, terminate in a transverse plane, indicated at P, above which the body of the bit is smoothly tapered, as at 19, to merge with the lower cylindrical end of the shank 11.

The lower working face 20 is provided near its center with a generally conical blind recess, indicated at R (FIG. 2) from which the surface extends outwardly through a convexly smooth peripheral surface portion 21 to the segmental-cylindrical surfaces 16, 16a and 16b. Three

water grooves

22, 22a and 22b extend from near the upper closed apex of said recess R in a generally radially outwardly direction and then along the convex portions 21 and upwardly along the respective segmentalcylindrical lateral faces 16, 16a and 16b, preferably through the tapered surface 19 (FIG. 2).-

Said water grooves

22, 22a and 22b are constricted in their crossa sectional area toward the peripheral extent thereof, as at 23, 23a and 23b for a purpose that will laterv appear. Bores 24, 24a and 24b extend downwardly in an inclined direction from the counterbore 13 of the shank recess 12 into the

respective grooves

22, 22a and 22b, near the midpoints of the length thereof. Thus, the drilling fluid introduced into the recess 12 of the hollow shank 11 is discharged, during operation, through the respective bores 24, 24a and 24b into the

corresponding water grooves

22, 22a and 22b. The cross-sectional area of each of said bores 24, 24a and 24b, is considerably greater than the cross-sectional area of the corresponding water grooves so as to increase the pressure and therefore the velocity of the drilling fluid as the same enters and flows through the water grooves. The restriction of said water grooves toward their respective peripheral extents tends to build up a back pressure causing the drilling fluid to flow inwardly through the respective grooves toward the apical recess portion R for discharge laterally therefrom through an enlarged water course 25, which constitutes an extension of the water groove 22a and that opens for discharge of the drilling fluid through the non-reaming facet 17b. Larger portions of earth formation, and particularly those broken off within the apical recess R, can thus be discharged through said enlarged water course 25 and pass freely upwardly between the non-reaming facet 17b and the wall of the bore hole.

As viewed in FIGURE 1, with the bit turning counterclockwise, as indicated by the arrow, that edge of each of the

grooves

22, 22a and 22b which constitutes the diamond set blade will be termed the leading edge, and the other will be termed the trailing edge. With this understanding, the

respective grooves

22, 22a and 22b have trailing edges 26, 26a and 26b, and have leading edges 27, 27a and 27b. The respective leading edges, as best illustrated in FIGURE 3 by the leading edge 27a, are constituted by blade-like projecting ribs formed at the junction of the adjacent portion of the lower working face 20 and the wall of the groove, in this case, the groove 2211. Since all of the projecting ribs are similar, only that best shown in FIGURE 3 need be described. The portion of the lower working face indicated by the reference numeral 20a slopes upwardly and away from the projecting rib 27a, while the adjacent wall 28a of the groove 22a lies in a substantially vertical plane, with the result that a bladelike rib is formed at the junction of the two surfaces 20a and 28a. A single row of closely set diamonds 29 is embedded in the edge 27a formed by such blade-like projecting rib, and as shown in FIGURES 1 and2, this single row of diamonds extends from within the blind recess R continuously along the radial length of the edge 27a and upwardly along substantially the full extent thereof on the lateral segmental cylindrical reaming face 16a. The diamonds, or other hard abrading elements, are set relatively closely together, preferably but not necessarily in a single row right in the very edge itself, and are suitably embedded in the matrix or alloy of which the working face of the bit is constituted so as to exert maximum cutting, or abrading, action throughout the usefullife of the diamonds during the drilling operation.

The other, or trailing edges of the

grooves

22, 22a and 22b, are all generally similar and all generally follow the contour of the corresponding leading edge of the respective grooves but in a plane slightly offset upwardly and/ or inwardly from a transverse plane passing through the diamond-set edges 27, 27a and 27b. This can best be understood by reference to FIGURE 3, wherein the letter D represents the amount of offset between the plane of the trailing edge 26a and that of the leading edge 27a. The distance D may vary from as little as from bi or so, up to A" or greater, depending upon the nature of the earth formation to be drilled, the fluid energy available at the bit, the torque limits of the drill stem and the weight available to be applied to the bit during drilling. The trailing edge 26a is preferably smoothly rounded at the junction of the adjacent groove wall 36a and portion 31a of the working face of the bit. Said working face portion 31a is preferably nearly flat, or only slightly sloping, for a substantial distance away from the edge 26a, thereby forming, in effect, an abutment, or bumper, that minimizes the flow of drilling fluid between such abutment and the bottom of the bore hole. Said abutment 31a and the similar abutments 31 and 31b, are all free from abrading particles, or diamonds, and therefore, exert no cutting or abrading action. They do, however, limit the bite taken by the bladetype edges by the fact that the abutment, or bumper surface, rests against the bottom of the hole at all times during drilling.

In operation, as a result of the correlation between the flow capacity of the bores 24, 24a and 24b, and the

corresponding water grooves

22, 22a and 22b, and also as a result of the restriction of said water grooves toward their peripheral extent, the drilling fluid flows along said water grooves at a relatively high velocity to carry loose particles of earth formation away from the bottom of the hole. In particular, by virtue of the blade-like projecting ribs 27, 27a and 27b, and their corresponding, upwardly offset abutmen'ts 3:1, 31a and 31b extending away from the leading edges 26, 26a and 26b, there is a high velocity flow of' the drilling fluid over and around the diamonds 29 in the leading edges of the water grooves and this serves to cool the diamonds and to free them from particles formed by the abrading or cutting action of the diamonds. Inasmuch as the water groove 22:: is somewhat longer than the water grooves 22 and 22b, the bore 24a supplying said water groove 22a is of larger capacity than either of the bores 24 or 24b. Also, the blade-type projecting rib, or edge 27a, is longer than the other edges 27 and 27b, in that the blind recess R is ofiset from the true axis of the drill bit in the direction toward the non-reaming lateral facet 17b and the edge 27a continues for the length of said water groove 22a up into said recess R. Consequently, there is some ab rading action caused by the diamonds 29 that lie within the apical recess R, and the particles of earth formation resulting from such abrading action of those diamonds are carried along with the stream of drilling fluid that discharges radially outwardly through the enlarged water groove 25 through the nonreaming facet 17b. Because of the axially offset position of the conical recess R, there is more of a crushing than of an abrading action, with a result that larger particles of earth formation are produced within the extent of the recess, and these larger particles are readily accommodated by the larger cross-sectional area of the water groove 25 and by reason of the relatively large free space between the lateral facet 17band the wall of the bore hole.

In general, the diamonds 29 are selected of a size and shape suited for the purpose, and are set along the leading edges 27, 27a and 27b in such a manner as to accentuate the blade-type projecting ribs afforded by the contour of the lower working face 20 and the

water grooves

22, 22a and 2212. As stated, the rows of said diamonds 29 are preferably only one diamond in width. This results in a great saving in the cost of diamonds, as compared with prior art drill bits in which the diamonds are set in closely spaced relation over substantially the entire lower and lateral working faces of the drill bit.

It will, of course, be understood that various details of construction and arrangement may be varied somewhat without departing from the principles of this invention, and it is, therefore not the purpose to limit the patent granted hereon otherwise than necessitated by the scope of the appended claims.

I claim as my invention:

1. A drill bit comprising:

a bit body having at its upper end an axial recess and at its lower end a working face,

said working face beingrforrned with a blind recess near the center thereof and with a plurality of water grooves extending from said recess to the periphery of said working face,

the working face along a corresponding one side of each of said grooves forming with the adjacent groove wall a narrow radially extending blade-like projecting rib,

each of said ribs being set with closely spaced abrasive particles along the length thereof and presenting abrasive cutting edges toward the groove side thereof,

the working face along the other side of each groove being generally flat and ofiset axially upwardly of a plane transverse to the axis and passing through said abrasive cutting edges to form a bumper area extending continuously from said groove side to the next succeeding rib,

there being a bore through said bit body from said axial recess opening into each of said grooves radially outwardly of said blind recess to discharge drilling fluid into each of said grooves for high elocity fiow across said recess and over said abrasive cutting edges the full lengths thereof,

said bumper areas serving to limit the bite taken by said blade-like projecting ribs.

2. A drill bit comprising:

a bit body having at its upper end an axial recess, at its lower end a working face and at its periphery lateral segmental cylindrical reaming faces with intervening radially inward non-reaming facets,

said working face being formed with a blind conical recess near the center thereof and with a plurality of water grooves extending from and across said recess to the periphery of said working face and upwardly along said segmental cylindrical reaming faces,

the working face along a corresponding one side of each groove forming with the adjacent groove Wall a narrow radially extending blade-like projecting rib,

each of said ribs being set with substantially a single row of diamonds extending therealong and presenting and abrasive cutting edge toward the grooved side thereof,

the working face along the other side of each groove being generally fiat and offset axially upwardly of a plane transverse to the axis and passing through said abrasive cutting edges to form a bumper area limiting the bite of said ribs,

there being a bore .through said bit body from said axial recess opening into each of said grooves radially outwardly of said recess to discharge drilling fluid into each of'said grooves for high velocity flow through said grooves, across said recess and over said abrasive cutting edges.

3. A drill bit comprising:

a hollow cylindrical shank,

an enlarged bit body at the lower end of said shank having a lower face of generally triangular configa uration in bottom plan merging at its periphery into three coaxial segmental cylindrical lateral reaming faces and three intermediate non-reaming facets each of greater peripheral extent than any of said segmental cylindrical faces and lying radially wholly within the latter,

said lower face having near the center thereof a closed recess and three water grooves extending outwardly therefrom along said lower face and upwardly along said segmental cylindrical lateral faces,

said lower face along a cor-responding one side of each of said grooves forming with the adjacent groove wall a narrow radially extending blade-like projecting rib and along each corresponding other side of said grooves forming an abutment offset axially upwardly of the corresponding rib and conforming generally in contour to one of said ribs throughout the length thereof,

each of said ribs along the adjacent groove wall edge bein set with abrasive particles extending from adjacent said recess outwardly along said groove wall edge,

there being a bore through said bit body from said hollow shank opening into each of said grooves radially outwardly of said recess to discharge drilling fluids into said grooves for high velocity flow therealong and across said recess and for cooling said abrasive particles in said ribs along said grooves and the upward extensions thereof.

4. A drill bit as defined in claim 3, wherein, said grooves are restricted in cross-section toward the periphcry of said lower face.

5. A drill bit as defined in claim 3, wherein, an additional water groove extends from said recess in substantially diametrical alignment with one of said three grooves to the nearest of said non-reaming facets for discharge of drilling fluid upwardly along said facet.

6. A drill bit comprising:

a bit body having at its upper end an axial recess and at its lower end a working face smoothly merging at its periphery into upwardly extending lateral reaming faces and intermediate radially inwardly relieved non-reaming facets,

said working face being formed near the center thereof with a closed recess and with a plurality of water grooves extending from and across said recess to the periphery of said working face and upwardly along said lateral reaming faces of said bit,

a radially extending blade-like projecting rib formed along a corresponding edge of each of said grooves, substantially the full length thereof,

the working face along the other side of each of said grooves extending back from one groove edge to the next groove edge to form therebetween a generally fiat abutment similar in contour to the contour :of said projecing rib but offset axially upwardly from said rib substantially the full length thereof to limit the bite vof said rib during drilling,

there being a bore through said bit body from said axial recess to each of said grooves radially outwardly of said recess to discharge drilling fluid into said grooves for high velocity flow therealong and across said recess,

and a narrow row of abrasive particles set along each :of said blade-like projecting ribs for substantially the full length thereof,

the working face being otherwise free of abrasive particles.

, 7, A drill bit as defined in claim 6, wherein, there is an addtional groove, but without any bore leading directly thereinto, formed substantially as a diametri-cal continuation of one of said first-named grooves on the other side of said closed recess from said one groove and discharging along a radially inwardly relieved non-reaming facet.

'8. A drill bit as defined in claim 6, wherein, the lower 'working face is of generally triangular configuration in plan and is defined by three segmental cylindrical lateral reaming faces including upward continuations of said ribs and three intermediate non-reaming facets each of the latter of which is of greater peripheral extent than each of said segmental cylindrical faces and lies wholly Within the cylinder generated by said segmental cylindrical faces.

"9. A drill bit comprising:

said working face being formed with a plurality of water grooves extending from near the center of said face to the periphery thereof,

each of said water grooves being restricted in crosssection toward the periphery of said working face, the working face along the corresponding one side of each groove forming with the adjacent groove wall a blade-like projecting rib,

each of said ribs being set with closely spaced abrasive particles along the length thereof and presenting abrasive cutting edges toward .the groove side thereof,

the working face along the other side of each groove being generally flat and offset axially upwardly of the plane transverse to the axis and passing through said abrasive cutting edges,

there being a bore through said bit body from said axial recess to each of said grooves to discharge drilling fluid into each of said grooves for high velocity flow with said abrasive cutting edges,

each of said bores being of larger cross-sectional area than that of a groove into which said bore discharges, 7

10. A drill bit comprising:

the working face along the corresponding one side of each groove forming with the adjacent groove wall a blade-like projecting rib,

each of said ribs being set with a single row of closely spaced diamonds extending therealong and presenting abrasive cutting edges to the groove side thereof,

the Working face along the other side of each groove being generally flat and offset axially upwardly of a plane transverse to the axis and passing through said abrasive cutting edges,

there being a bore through said bit body from said axial recess to each of said grooves to discharge drilling fluid into each of said grooves for high velocity flow over said abrasive cutting edges.

References, Cited by the Examiner UNITED STATES PATENTS 2,371,489 3/45 \Villiams 175329 2,371,490 3/45 Williams 175-3-29 2,931,630 4/60 Grady 175-330 2,990,897 7/61 Short 175330 2,998,088 8/61 Pennington 175-329 FOREIGN PATENTS 1,249,346 11/ France.

CHARLES E. OCONNELL, Primary Examiner.

Claims

10. A DRILL BIT COMPRISING: A BIT BODY HAVING AT ITS UPPER END AN AXIAL RECESS AND AT ITS LOWER END A WORKING FACE, SAID WORKING FACE BEING FORMED WITH A PLURALITY OF WATER GROOVES EXTENDING FROM NEAR THE CENTER OF SAID FACE TO THE PERIPHERY THEREOF, THE WORKING FACE ALONG THE CORRESPONDING ONE SIDE OF EACH GROOVE FORMING WITH THE ADJACENT GROOVE WALL A BLADE-LIKE PROJECTING RIB, EACH OF SAID RIBS BEING SET WITH A SINGLE ROW OF CLOSELY SPACED DIAMONDS EXTENDING THEREALONG AND PRESENTING ABRASIVE CUTTING EDGES TO THE GROOVE SIDE THEREOF, THE WORKING FACE ALONG THE OTHER SIDE OF EACH GROOVE BEING GENERALLY FLAT AND OFFSET AXIALLY UPWARDLY OF