US2497144A - Drill bit - Google Patents

Description

A. L. STONE Feb. 14, 1950 DRILL BIT 2 Sheets-Sheet 1 Filed Nov; 25, 1945 #1321971. $70111 /& 23 22 24 23 3 INVEN TOR.

fir TOP/VE) A. L. STONE Feb. 14, 950

DRILL BIT 2 Sheets-Sheet 2 Filed Nov. 25, 1945 INVENTOR.

Patented Feb. 14, 1950 UNITED STATES ATENT OFFICE- DRILL BIT Albert L. Stone, Palos Verdes Estates, Calif.

Application November 23, 1945, Serial No. 630,197

8 Claims.

This invention has to do with improvements in well drilling bits, particularly rotary bits to be used for drilling rock or other hard formations presenting diflicult considerations with respect both to cutting of the formation and the removal of the severed particles or cuttings.

One major object and characteristic of the invention is the adaptation in a rotary drill bit of a rotary cutting or abrading wheel driven independently of the bit rotation and having certain important and distinctive functions in relation to the cutting efiiciency of the bit. Of particular importance in contributing to that efliciency and the capacity of the bit to penetrate hard formaion to better advanage than the usual bits, are (1) the cutting functions of the rotary cutter, and (2) the maintenance of fluid circulation and immediate removal of cuttings from the formation surfaces against which the cutter acts.

In its preferred forms the present bit comprises a fluid driven rotary cutter contained in the bit body in such relation to the bottom cutting face of the body as to be capable of high speed cutting or abrading contact with the formation surface, or a portion thereof, being drilled away. One main function of the cutter is to remove the formation at the center of the hole, thus eliminating any core that might otherwise tend to form, and also the formation at a central location where, in the case of bits having a non-coring action as by a central or diametrically continuous cutting blade or face, a localized center grinding effect would occur without adequate circulation to conduct away heat generated by the extreme friction. The present fluid driven cutter may be centered relative to the hole for rotation about a transverse axis so that the bottom surface of the cutter removes at least that portion of the formation at the center of the cutting area of the bit. As will appear, the rotary cutter may be adapted to cut across the full diameter of the bore, or it may be so mounted in the bit body as to selectively work against a central or core area otherwise unsevered by the cutting faces of the body.

The rotary cutter may take essentially the form of a turbine or impeller wheel carrying vanes against which one or more streams of high velocity circulating fluid are directed to drive the cutter at relatively high speed. The wheel has peripheral cutting surfaces, as presented for ex ample by annular side portions beyond the vanes, and by reason of the open or vaned form of the wheel, movement of circulating fluid is continuously maintained at its cutting faces and across 2 the bottom surface of the hole. Thus the effect of the fluid driven cutter is to assure constant and complete removal of cuttings with greater efficiency than is permitted by the usual bit.

A further important feature and object of the invention is to provide an improved bit having greater hard formation drilling efilciency by incorporation of diamond particles in its cutting or abrading faces, and specifically in the cutting surfaces of either or both the body and high speed rotary cutter of the present type of bit. With particular reference to the cutter wheel, the presence of diamond particles in its outer face gives the wheel, especially at high rotative speeds, capacity for very efficient cutting or abrading action against the hardest of formations.

Certain typical embodiments of the invention shown in the accompanying drawings will serve more clearly to illustrate the above mentioned and further contemplated features and objects. Referring to the drawings:

Fig. 1 is a side elevation illustrating one embodiment of the invention;

Fig. 2 is a section on line 22 of Fig. 1;

Fig. 3 is a section on line 3-3 of Fig. 2;

Fig. 4 is a section on line 44 of Fig. 2;

Fig. 5 is a view similar to Fig. 3 illustrating a variational form of the invention;

Fig. 6 is a section on line 6-6 of Fig. 5;

Fig. 7 is a section on line 1--1 of Fig. 6;

Fig. 8 is a fragmentary section showing a variational form of rotary cutter; and

Fig. 9 is a section on line 9-9 of Fig. 8.

The drill bit illustrated in Figs. 1 through 4' comprises a suitable body structure I 0 which may have any suitable means, not shown, for attachment to the usual drill string through which circulating fluid is pumped for delivery through the body bore I l to the rotary cutter as will presently appear. Generally speaking, the body proper may be designed to have any suitable or specific form or arrangement of cutting faces rotatable against the bottom of the well bore l3 to cut the formation l4. Merely as typical, the body is shown to have curved face portions or ribs l5 and 16 between which the body surface is channeled at ll to facilitate the flow and distribution of circulating fluid over the cutting area of the bit.

mond particles l8 are embedded in the cutting faces of the body, it being understood that the diamonds may be embedded therein in any suitable manner as by the known methods of caulking into the cutting faces individual diamonds, or diamond-containing metallic slugs, or by facing the surfaces with metallic matarix containing relatively finely divided diamond particles.

The body contains a central or axially alined vertical opening or slot having a top arcuate surface 2| below which the sides of the slot are defined by' and in accordance with. the curvature of the body rib portions l6 through which the slot is formed or cut. The slot 20 contains a rotary cutter generally indicated at 22 preferably in the form of an impeller or turbine wheel haying spaced sides 23 interconnected by curved vanes 24, the particular shapes and; extents; of which may be selected or determined to. best utilize the energy (velocity) of the fluiddirected against them to produce high speed rotation. of the cutter. chargedv from bore. H through one or more-nozzle passages 25. against. the cutter vanes 24' to. cause. rotationof. the cutter at high speeds, the. rate. of which in. individual instances. will depend upon such. considerations. as, the fluid. pressure obtainable. at the nozzle. 25. and the fluid head. against whichthe liquidisdischarged, into the well.

The. cutter may be formedwithlsolid. or tubular trunnions. 26. journaled. for. rotation within bearings. 211. The bearings. may be specially selected for resistance, to. abrasive. fluid, andv desi'rably may be. made. of rubber. specifically as sleeves or other suitable. bearing. form. When hollow. or tubular, the trunnions-2B. provide passages Zllthrough which fluidlmay escape fromthe. center of the cutter. wheel into the body recesses 29 and thence upwardly into, the fluid column. in the well; As will. be. understood. Without-necessity for specific illustration,,i the trunnions. are. solidly formed, the body metal may be extended. to occupy all or a portion of' the. recesses 25..

Proper. clearances are. maintained between the cutter and the surfaces 20'- and 21 to permit free rotation.of the cutter. Referring to. Fig.,-2,.it.will be noted. that surface 2|, extended. by the body portion 30 forms with the curved face 3] of the hole apartial; peripheral closure about the. wheel, confining the fi'uid for application of its velocity force or headto the vanesfi. The clearance32 maintained at theperipherali porti'onofthe cutter opposite the portion 30;. permits escape of. the fluid and cuttingsbeing. carried. upwardly, by the. wheel, into the well' fluid. column,v The cutting faces .ofthe, wheel may include. the peripheral faces of'both the. annular sides, 23,. and, if. desired. the. outer edges. of the vanes. 2.4;. As.in the. case of. the body ribs I5 and, |.6,.thev cutting, surfaces. of the. wheel may contain embedded diamond particles 33.which,,at the high. speedof the. cutter. rotations. give the wheel highly.- efficient cutting. andabrading actionagainst the. formation.

In the. operation of. the. tool,, rotationof the. bit body produces corresponding. cutting. actionof the, curvedsurface bod-y. portions I 5.and Idagainstthe. formation. Simultaneously, the. independently driven. cutter wheel. 22 is. given an; independent; cutting andabrading action. againstsubstantially the=full hemispherical bottom surfaceofthehola. A further importantfunction. of; the cutter tn constantly maintain. a. high. velocity sweep of. circulating fluid against the. formation surface being acted. upon by all the cutting faces, resulting; in. the immediate: removal. of. cuttings; and.

dissipation of. frictionally developed heat. At.

this. point it. may: be mentionedthat the wheel;

High pressure circulating fluid is dismay be so located that its peripheral cutting faces may be ofi-set sufflciently above the cutting surfaces of the body that the vertical load and pressure of the tool against the bottom of the hole will be assumed by the body, at least to a degree relieving the rotating cutter of bottom pressure to an extent that it will be capable of high speed rotation under the influence of the fluid stream directed against it.

The variational. form of the. invention shown in Figs. 5 to 7 is generally similar to the described embodiment except with respect to certain modifications in the body structure and the adaptation of the rotary cutter for selectively removing a core portion of the formation. Here the body 35 has the annular bottom portions 36 forming the cutting faces 3.! and 38 at the outside of a central recess 39 which receives a core portion 40 of the formation as the bit progressively cuts the hole. Delivery of circulating fluid from the bore II to the cutting faces of the body may be effected in any suitable. manner, as for. example, through passages. 46 from which the fluid is discharged into channels or. grooves 41,48 and 49 respectively in the. inside, bottom. and exterior cutting faces of the body portion 3.6.

The. function of the cutting. wheel 4! is to remove the core. 4 at. a rate corresponding to the rate of. penetration of the bit. As illustrated, the bottom portion of. the cutter may extend into the recess-39 below thev body surface 4H 50 as to cut the core against a segmental spherical surface 42. The cuttingsare immediately swept into the fluid stream in the cutter to be discharged through the openings 43; Except at the bottom, the rotary cutter 41 is peripherally enclosed within the circular body opening dill, it being understood that ample clearances may be maintained at all 10- cations. between the cutter and the body to permit free. rotation of the cutter. The cutting faces of the body and wheel may if. desired contain embedded diamond. particles as described with reference to Figs. 1'. to 4'.

Figs. 8 and; 9 illustrate a variational form of rotary cutter in which the vanes. extend inwardly to the radial center of the wheel and carry vanes 51. centered transversely of the vanes to div-ide the. fluid. stream projecting against them. Toward the. center of the. wheel the vanes widen at 52 to form bafflev surf-aces servingto deflect the fluid streams into. the outlet passage 53 formed by, the. hollow trunnions 5'4.

Itshonld be observed that the body may have any suitable. section. or other. construction permitting installation, of the rotary cutter and its bearings. and final. integration of the body.. Merely as. illustrative, initially the body in both. described forms of the invention may be made in separate upper and lower sections, for example, aboye and below thetransverse planes of section lines l4 and; in Figs. 2. and 6. After insertion of the rotary cutter and its bearings in one. of the sections, the other may be applied thereto and. the twosections welded together at the interfaces corresponding to the locations of. the section lines.

I claim:

1. A well drill bit comprising a rotatable body carrying; a bottom formation cutting means, a circular'cutter carried by and rotatable within a central. portionof the; body to cut the formationported by theengagement of said. cutting means.

.5-- witlrthe; formation the=cutter is. thereby permitted relatively high speed rotation, and means for rotating said cutter at such relatively high speed independently of the body rotation.

2. A well drill bit comprising a rotatable body having a bottom cutting face, a circular cutter carried by and rotatable within a central portion of the body to cut the formation at the center of the cutting area of said body face while the body and cutter are vertically supported by the engagement of said cutting means with the formation and the cutter is thereby permitted relatively high speed rotation, and means for rotating said cutter at such relatively high speed by fluid pressure independently of the body rotation.

3. A well drill bit comprising a rotatable body having a bottom formation cutting face, a circular cutter carried by and rotatable within a central opening in the body about a transverse axis while the body and cutter are vertically supported by the engagement of said cutting means with the formation and the cutter is thereby permitted relatively high speed rotation, vanes carried by the cutter, and means directing fluid against said vanes to rotate the cutter, said formation cutting face of the body being curved substantially in accordance with the curvature of said cutter.

4. A well drill bit comprising a rotatable body having a bottom formation cutting face, a circular cutter carried by and rotatable within a central opening in the body about a transverse axis While the body and cutter are vertically supported by the engagement of said cutting means with the formation and the cutter is thereby permitted relatively high speed rotation, said cutter having spaced sides having bottom cutting contact with the formation, vanes extending between said sides, and means directing fluid against said vanes to rotate the cutter at such relatively high speed.

5. A well drill bit comprising a rotatable body having a bottom formation cutting face, a circular cutter carried by and rotatable within a central opening in the body about a transverse axis while the body and cutter are vertically supported by the engagement of said cutting means with the formation and the cutter is thereby permitted relatively high speed rotation, said cutter having spaced sides having bottom cutting contact with the formation, vanes extending between said sides, diamonds embedded in the peripheral surfaces of said sides, and means directing fluid against said vanes to rotate the cutter at such relatively high speed.

6. A well drill bit comprising a rotatable body carrying bottom formation cutting means, a circular cutter carried by and rotatable within a central opening in the body about a transverse axis while the body and cutter are vertically supported by the engagement of said cutting means with the formation and the cutter is thereby permitted relatively high speed rotation, said cutter having bottom cutting contact with the formation throughout a substantially semi-circular extent of the cutter, vanes carried by the cutter, and means directing fluid against said vanes to rotate the cutter at such relatively high speed.

7. A Well drill bit comprising a rotatable body having a bottom formation cutting face, a circular cutter carried by and rotatable within a central opening in the body about a transverse axis while the body and cutter are vertically supported by the engagement of said cutting means with the formation and the cutter is thereby permitted relatively high speed rotation, said cutter having bottom cutting contact with the formation at a location above said bottom cutting face of the body, vanes carried by the cutter, and means directing fluid against said vanes to rotate the cutter at such relatively high speed.

8. A well drill bit comprising a rotatable body having a bottom formation cutting face, a circular cutter carried by and rotatable within a central opening in the body about a transverse axis while the body and cutter are vertically supported by the engagement of said cutting means with the formation and the cutter is thereby permitted relatively high speed rotation, said cutter having bottom cutting contact with the forma- 1- tion, trunnions supporting the cutter and journaled in lateral openings in the body, vanes carried by the cutters, and means directing the fluid against said vanes to rotate the cutter at such relatively high speed, said trunnions containing openings through which fluid leaving said vanes escapes.

ALBERT L. STONE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,391,626 Gilthorpe Sept. 20, 1921 1,870,592 Schuerman Aug. 9, 1932 2,034,073 Wright Mar. 17, 1936 2,184,066 Zublin Dec. 19, 1939 2,207,187 Zublin July 9, 1940 2,268,775 Potvin Jan. 6, 1942

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