US2111781A

US2111781A - Well drilling bit

Info

Publication number: US2111781A
Application number: US88990A
Authority: US
Inventors: John H Howard
Original assignee: Individual
Current assignee: Individual
Priority date: 1936-07-06
Filing date: 1936-07-06
Publication date: 1938-03-22
Anticipated expiration: 1955-03-22

Description

" Q Patented 22, 19 38 v UNITED? S T AI ATENT v O CE This invention relates to a well drillingtool and-relates more particularly to a drilling bit tor use in the rotarymethod oiwell drilling. A gen- .eral object of the inventionis to' provide rpm tical eflective :wellgbit embodying an improved 'and very eillcient combination of cutters.

Another object otthis invention is to provide f a rotary well drilling bit in which the-outer or peripheral portion oiflthe well bore is drilled by 10 rotatable cutters of one type and the remaining inner portion of the bore is :drilled by rotatable cutters of: another typewhereby the maximum efliciency of both forms or cutters is obtained.

Another object of this invention is to provide a well Abit embodying roller type cutters-rotatably supported for rotation about substantially horizontal or only partially inclined axes to cut an, annular channel at the peripheryoi the wellbore bya rolling and crushing actiomand embodying scraper type cutters-"supported for rotation about nearlyvertical axes to cut away the remaining portion of theboreby a scraping orshearing' action. I

Another object of' this invention isto provide aiwell bit or the charactermentionedinwhich the slightly tilted or nearly verticalshearing type cutters are self-sharpening" through their en gagementl with the earth formatio AnotherAobject of this invention is to provide a bit of the character mentioned. in which the slightly tilted or nearly vertical scraping type cutters are forced to rotate and; therefore,

very eflicientand long.wea.rmg

Another object of this "invention 'is Atoms-wid A a novel and' highly eflicien't- ,forniof rotatable cutter for a welldrilling bit whichcutter is intended to be supported for rotation about a ;-nearly vertical axis and embodies reaming cutting teeth toassure its rotation; I

A40 Another-object 01' this invention is to provide a well bit oi the character mentioned in which the crushing roller cutters are mounted or: pins which are dependably supported at both their inner and outer ends.

Another object oi this invention is to provide a well drilling bit of the characterfmentioned in which the nearly vertical rotatable scraping cutters are devoidAof teethat their lo'we'r ends and; therefore are not as liable to. failure asthe .60 to hed nearly verticalcutterslheretotoreintro A. Another object 01 this invention is toprovide a well drilling bit of the charactermentioned in which astream oi, circulation fluid is discharged A downwardly irom within the lower end oieach scraper type cutter to clear its cutting edge or mud and cutti ll,

The various objects and features of my invention will be fully understood from the following detailed description of a typical form 5 e and application of the invention, throughout which description reference ismatle to the acri 1 is side elevation org-theimnroved bit provided by this invention with a portion in ver- 10 tical cross section" to'ilhistrate the rotatable mounting clone or the "scraper type cutters Fig. 2 is an enlarged i'rsamentaryvertical de- .tailed seamen view taken mbstantifll! as indicatiad by line 29-! on Fig; 1. 3 is atransis versedetailed sectional View taken as by lineH on Fig. i and Fig. 14 is a bottomelem e meba- A a 1 A a Y The-rotary well-drilling bit oi'the present invention includes. senerslly.A a shank or ll, 20 crushing roller type cutters I i rotatabiy' su on the body It, and shearing or type cutters i2 rotatably supportedtonthe II.

The shank or body" "is to beconnected with the-lower end of arotsry drilling 2 string. Thebody ll may be integral and may be generally cylindrical. Means is proyidedatthe upper end of the body l'l-tofa'cllitate its connec-' tion withthe well drilling string. In the'vpar-v- It toreceive spin on the lower end oi the drillingstring. "1he.'lower-} end portion or the body ll maybe enlarged in diameten- II is "provided with pairs avings or legs is and II to receive and carry the cutters II and their mount- In theparticular embodiment of thejinvention illustrated there "are two diametrically opposite pairs oflegs lland II, The legs i4 and I! are integral with the'body ll andpmlct 40 downwardly and outwardly from its'lower end. 'I'he'legs II are the outer legs 'oi the pairs. and may be somewhat thibker than the inner legs I}. The legs ll and II oi each pair aresub'stantially parallel and are prqvided attheir inner sides 45 with opposing raised bearing surfaces it, and i 6', respectively. The lower outer corners or the outer legs II are bevelledto besubstantially vertical and flat shoulders I! are provided on the The lower inner away'and flat shoulders All are provided on the lower ends of,- these. legs;

' .I'hebody n is provided withspaced is to carry the means for rotatably supporting the cutters i2. In the embodiment of the invention illustrated there are two substantially diametrically opposite bosses l3 projecting downwardly at 5 the lower end of the body in. The bosses II are partially cylindrical and their longitudinal axes are slightly inclined downwardly and forwardly with respect to the direction of rotation of the bit. Due to the pitch or slight inclination of the bosses i3 they are not directly diametrically opposite but have their axes at opposite sides of a diametrical plane. The lower ends of the bosses l3 are flat and are normal to their longitudinal axes.

The cutters II are operable by a crushing action to form an annular cut or channel in the peripheral portion of the well bore. The cutters II are in the nature of roller cutters. The roller cutters II have central longitudinal openings i9 and flat normal ends. Peripheral cutting teeth 23 are provided on the cutters ii. The teeth 20 preferably overhang or project outwardly beyond the outer ends of the cutters The innerand outer corners of the teeth 20 are preferably bev-- ellecl off, as illustrated in the drawing. The teeth 23 may be straight or spiralled, if desired or found practical. The two roller cutters Ii may be identical in size and shape.

The invention provides effective dependable means for rotatably supporting the roller cutters |I between the spaced legs l4 and IS. The means for rotatably supporting the cutters include bushings 2|. The bushings 2-|,are tubular cylin drical members and are provided at their inner ends with annular thrust'flanges 22. The flanges 22 areadapted to bearagainst the surfaces l5. Extensions or lugs 23 are provided on the thrust flanges 22 and cooperate with the shoulders to prevent rotation of the bushings 2| and to transmit upward thrusts directly to the legs I5. The outer end portions 2| of the bushings 2| are reduced'in diameter and carry thrust washers 24. The washers 23 are adapted-to bear outwardly against the thrust surfaces It. The cutters i are rotatably supported on the bushings 2| between the flanges 22 and the washers '24. In practice the cutters I may be rotatably supported on the bushings 2| through roller bearings 25. The flanges 22 and the washers 24 serve to space the cutters II from the legs I3 and ii and to transmit end thrusts to the legs;

Shafts or screws 26 are passed inwardly through openings 21 in the legs l5 and have their 3 outer portions threaded in openings 28 in the legs, II. The

openings

21 and 28 are inclined downwardly and inwardly having longitudinal axes normal with the surfaces Il and I5. screws 26 are provided at their inner ends with heads 28' bearing outwardly against the legs IS. The headed and threaded screws 26 serve to tie together the lower portions of the legs I4 and IS. The screws 23 pass through the bushings 2| to support the bushings between the legs It and IS. Notches 29 are provided in the outer sides of the legs I at the openings 28 and end parts of the screws 26 are peened into these notches 29 to lock the screws against unthreading. The cutters supported as just described are rotatable about downwardly and inwardly inclined axes and project downwardly beyond the lower ends of the legs i4 and i5 to act on the formation at the bottom of the well bore and project slightly beyond the outer sides of the legs I4 to assist in cutting the bore to gauge. It is believed that it 75 will be understood by those skilled in the art how "uated or varying in external diameter.

tubular.

edges 32.

The

the roller cutters operate to cut an annular groove in the periphery of the well bore by a crushing rolling action.

The cutters.|2 are an important feature of the invention being of novel shape and construction. 5 The invention, as illustrated, includes two cutters i2 which may be .alike in size and shape. The cutters i2 are generally cylindrical though grad- The cutters J2 are preferably, though not necessarily. 10

As illustrated in the drawing each cutter l2 has a central longitudinal opening 30. The upper ends of the cutters ilarefiat and normal. In accordance withlthe invention the cutters I2 ,are"'substantially cup-shaped having depressions 15 or central sockets'3l in their lower ends.

sockets 3| are comparatively large in diameter and are provided to form or leave annular cutting edges 32 at the lower ends of the cutters. The cutting edges 32 are the principal cutting 20 edges of the cutters l2 and have shearing or scraping engagement with the earth formation as will be hereinafter described. The extreme lower ends of the cutters l2 are bevelled upwardly and away from the cutting edges 32. The 25 sockets 3| in the lower ends of the cutters I2 provide or leave cylindrical. walls at the lower ends of the cutters and the edges 32 occur at the lower ends of these walls.

The walls or surfaces of the sockets 3| are 30 hard faced with tungsten carbide, or the like, to provide the cutters with long wearing cutting The sockets 3| are comparatively deep so that the edges 32 are very long wearing. As the edges 32 scrape along the bottom of the well 35 bore the metal behind or surrounding the edges 32 being softer than the hard facing comprising the edges 32, wears away, leaving the edges 32 sharp. Due to the depth of the sockets 3| the edges 32 automatically remain sharp until the 40 tubular lower walls of the cutter |2 are almost entirely worn away.

In addition to the cutting edges 32 the cutters |2 are provided with reaming teeth 33. The upper portions of the cutters l2 are enlarged in 45 external diameter and longitudinally extending grooves 33' are formed in these enlarged portions of the cutters to form or leave the reaming teeth 33. The grooves 33 forming the teeth .33 are preferably of substantial depth to extend into 50 the bodies of the cutters I2. The reaming teeth 33 extend from the upper ends of the cutters |2 to circumferential lines spaced slightly above the upper walls of the sockets 3|. In the drawing the teeth 33 are shown as straight or axial, it 55 being understood that the reaming teeth 33 may be pitched or, spiralled, if desired. The teeth 33 being formed in the enlarged upper portions of the cutters i2 have active longitudinal edges for are slightly inclined downwardly and forwardly relative to the direction of rotation of the bit. Sockets or openings 34, having the desired slight inclination, enter the bosses l8 from their lower ends and extend upwardly into the body i0 proper. The longitudinal axes of the openings tatably supported on so that they may be easily and quickly removed for resharpening or replacement. "The body Ill is subjected to littleor no wear and'the various Having described o y atypical preferred form and app cationormy, invention I do not, wish be limited or restrictedto the specific details forth, but "wish for rotation about asubstantially transverse axis make an annular cut in the and positioned to peripheral portion oi the "well, and a cutter rotatably supported on the body'for rotationabout an axis inclined downwardly and slightly .i'orwardly relative to the direction of rotation vof the bit and having ascraping on the inner portion of the well.

'2. A rotary well drilling bitincluding, a a roller cutter rotatably supported on the bodyfor rotation about a-substantially transverse axis and positioned "to makean ahnularcut rin the peripheral portion or thewellyand a cutter rotatably supported on the body i'onrotation about an axis'inclined downwardly and forwardly relative tothe direction of" rotation of the bitythe last mentioned cutter having 'a continuous scraping edg 'jfor acting on the' innerportionof the wellbor; b

3. A rotary well drilling bit including, a body, a roller cutter rotatably supported on the body for rotation about a substantiallytransverseaxis and positioned to make an annular cutin the peripheral portion or the well, and acutter' rothe body for rotationa'bout an axis inclineddownwardly and forwardly rel ative to the direction of rotation of the bit. the last mentioned cutter having a continuous scraping edge for acting on' the inner portion of the well bore, and reaming teeth for contacting the side wall oi the bore to effect its rotation.

an axis inclined V tive to the direction of rotation of the bit, there the cutter ing an endless x 4. A rotary well drilling bit including, body; and a substantially cylindxicalcutter supported on the lower end ofthe body for rotation about downwardly and forwardly relabeingan .opening in the lower end of leaving a-wall of tubular form'whose lower end presents an annular-scraping edge.

5. A- rotary well drilling bit including, a body,

and a-cutter supported bodyjtor rotation about I wardly and slightly forwardly relative to the direction 01' rotation of the bit, the cutter including an endless. scraping edgeon its lower end. I

6. A. rotary well n and afcutter supported on the lower end of the on the .lower end' 01' the body 101- :rotation, .abon'tan axis inclined downwardly and slightly forwardly relative to the di-" rection oi rotation or the bit, the cutter includand reamingteeth above,

7. A rotary said edge.

ing in its lower end edge for acting an axis inclined downdrilling :bit includins, a body.

scraping edge on its lower end, well drillingbit including, a

.4 2,111,781 7, on the tool prevent the cutters l2. from being and a cutter supported on the lowe end of the subjected toexcessive feed pressures. body for rotation about a nearly. ertical axk, The cutters l i ,and the cutters I2,are dependthere being an opening in the lower end of the ably supported for independent rotation about cutter leaving a wall of tubular form which preindividual axes. The cutters are supported sents an annular scraping edge. said cutter ineluding hard facing material lining the said socket whereby said wall wears away through use to maintain said edge sharp. l i

8. A rotatable cutter for a well drill including, a cutter body intended to be supported for rotation about "a generally vertical axis, said body having an opening provide a cutting edge; v 9. A rotatable cutter for a well drill including, a cutter body to be supported for rotation about a nearly vertical axis, said body having an opena well, a rotatable cutterhaving a scraping edge I at. its lower end and axially extending reaming and raisedreaming teeth on the periphery of the teethon its external surface, and means rotatably n y cutter on the lower end of the body to rotate about a downwardly and forwardadjacent and substantially parallelwith the side wall or the bore whereby the said teethengage the side wall to cause rotation ofthe cutter. p a

j 11. A wellbit including, a body to be rotated in a well, a rotatable cutter having a scraping edge at itslower end and axially extending reaming teeth on its, external surface 01' greater enective edge scrapeou the bottom of the bore and to have its outer peripheral surface adjacent and substantially Darallel'with the side wall of the bore whereby the" said teeth engage the side wall to cause rotation 01'. the cutter.

12. A well bit including a body having a fluid opening, a pin carried by the body and projecting from its lower'end, and a cutter rotatable on the pin about adownwardly and forwardly inclined axis,'said cutter having a'socket in its lower end leaving anannular scraping cutting edge foracting on the bottom wall of the bore, said pin having an opening for conducting fluid from the first mentioned opening to said socket.

13. A'rotary well drill including, a body having a pair-oispaced depending legs, a pin extend- ..ing between said legs to have its ends supported thereby, aroller cutter on said pin rotatable about a, substantially transverse axis to act on the bottom wall of the well, and ascraping cutter rotatably supported 1 by the body to rotate about a slightly downwardly andtorwardly inclined axis to act on the bottom wall of the well. 14. A rotary well drill including, a body, sub

stantially diametrically opposite pairs 01' spaced ported on saidpins iorrotation about downwar ly andginwardly inclinedaxes to have rolling contact withthe peripheral portion of the bore, and cutters rotatabLv supported by the body between said-pairs oi legs to rotate about 34 are normal to the lower ends of the'bosses l3 a with.. the openings and the openings 34 are tapered being of upwardly diminishing diameters. The means for rotatably carrying the cutters |2 include studs or pins 35 arranged upwardly in the openings 34. The upper portions of the pins 35 are tapered to properly fit the openings 34.

Means are providedv for removably lockingthe pins 35 in the openings 34. *Transverse openings 35 are provided in the bosses I3 and intersect-or partially join the openings 34 adjacent their outermost walleportions.- The openings 36 are elongate in cross section and have their major transverse axes incl'ined downwardly and outwardly. Notchesfl are provided in the exteriors of the pins 35 to complement or communicate 35: Wedges 33 are arranged or driven'in the open'ings35 to cooperate with the notches 31. The end portions or at --least the small end portions of the wedges 33 are turned over to prevent accidental displacement of the chamber 50 is provided in wedges from the openings 35. The wedges 38 cooperate with the notches 31 to dependably lock the pins against displacement from the openings 34 and serve to hold the pins against rotation. The pins 35 project downwardly from the bosses l8 and the cutters 2 are rotatable on the projecting portions of the pins. The pins 35 project through the openings 30 in the cutters l2 and have annular flanges at their lower ends to prevent displacement of the cutters. The flanges 40 are preferably received in annular re-.

cesses4i in the upper walls of the sockets 3|. Hardened thrust washers 42 are preferably interposed between the upper endsof the cutters |2 and the lower ends of'the bosses l3. Suitable dowels 43 hold the thrust washers 42'against r0- tation.

The cutters l2 are rotatably supported on the pins 35 to rotate about approximately vertical axes, the axes of rotation of the cutters being slightly inclined downwardly and forwardly relative to the direct rotation of the bit. Thus the lower ends of the sockets 3| on the cutters l2 are open and trailing portions of the cutting edges 32 have shearing or scraping engagement with the formation at the bottom of the well bore. The active portions of the cuttingedges 32 are in substantially the same horizontal plane as the edges of the teeth 20 where they contact the formation. The scraping cutters l2 are positioned and mounted so that their peripheral surfaces are substantially vertical where they are opposed to and adjacent to the side wall of the well bore so that these surfaces move in a circular path larger in diameter than the circular paths of the outermost surfaces of the bosses l3 and legs |4. Owing-to this disposition of the cutters H the reaming teeth 33 come into positive cooperation with the earth formation and are substantially vertical as they engage the side wall of the well. The engagement of the reaming teeth 33 with the side wall of the well bore reams the bore to gauge and effects the positive rotation of the cutters l2 about their individual axes. This independent rotation of the cutters l2 renders their edges 32 more effective and long wearing.

The invention provides means for flushing the cutters H and I2 of cuttings and mud. A fluid the body II! at the lower end of its socket l3. The chamber 50 receives the circulation fluid pumped downwardly through the drilling string. Ports 5| are provided in the body l5 and extend downwardly -tion with the chamber from the chamber 55 to the spaces between the adjacent legs l4 and I5. The ports 5| are inclined downwardly and outwardly and direct the circulation fluid against the cutting teeth 23 of the cutters II. The upper ends of the openings parts of. the tool is connected with the lower end of a suitable well drilling string. The drillin'g string is lowered into the well and is rotated and fed downwardly in the'usual manner to advance the bit into the formation. The roller cutters II are formed and positioned to cut a relatively narrow channel in the earth formation at the periphery of the well bore. This cut formed by the cutters II is slightly less than the desired gauge of the well bore. The cutters op erating by a crushing or rolling action take or transmit a substantial portion of the feed pressures on the bit relieving the cutters l2 of excessive feed pressures.

The cutting edges 32 of the slightly tilted cutters |2 have scraping engagement with the bottom wall of the well bore within the cut made by the cutters ll. The cutting edges 32 being endless or annular have smooth even engagement with the formation to effectively cut away thesame by a scraping action. As above described, the side walls of the sockets 3| are hard faced with tungsten carbide or the like to provide the cutting edges 32. As the tool operates the relatively soft metal surrounding and backing the cutting edges 32 wears away leaving the edges 32 sharp. The metal surrounding the edges 32 trails the edges 32 as they engage the formation and these trailing parts of the cutters |2 are worn away more rapidly than the edges 32. Further, asmall core may be left standing between the cutters i2 and the lower outer parts of the cutters I2 may be worn away due to their engagement with the core. The lower outer portions of the cutters |2 are relatively close to the center of the bit and are moving at a relatively high velocity when they engage the core and, therefore, wear away rather quickly. This wearing away of the metal about the edges 32 automatically maintains the edges 32 sharp. Thus the cutters l2 are self-sharpening through use.

The reaming teeth 33 have a larger effective diameter than the edges 32 and cutters II and engage the formation at the side wall of the well bore to cut the bore to the desired gauge. This reaming engagement of the cutting teeth 33 with the side wall of the well bore effects the positive rotation of the cutters l2 making the cutting edges 32 particularly efilcient and long wearing. It will be noted that the cutters'i2 present endless or annular principal cutting edges 32 for acting on the formation at the bottom of the well bore and do not have projecting blades liable to breakage or failure. The cutters II and I2 are spaced and related to assure the smooth even operation of the tool. The roller cutters II in taking a substantial portion of the down feed 15 In the operation of the bit provided by this 1 invention the body It carrying the various other downwardly and slightly forwardly inclined aires to have scraping contact with the bottomwall 0t the bore. i

.15. A rotary well drill including, a body, sub:

' stantially diametrically opposite pairs of spaced legs projecting from the lower end of the body, pins supported by said legs, roller cutters supported on said pins for rotation aboutdownwardlyand inwardly inclined axes to have rolling contact with the peripheral portion of thebore, and cutters rotatably supported by the body between said pairs of legs to rotate about downwardly and slightly forwardly inclined axes, the last mentioned cutters having scraping edges at'their lower ends contacting the bottom wall or the well and reaming teeth contacting the side wall of the bore.

contacting the side wall of the bore.

16. A rotary well drill including, a body, sul1- stantlally diametrically opposite pairs of spaced legs projecting from the lower end of the body,

plns supported by said legs, roller cutters supported on said pins for rotation about downwardly and inwardly inclined axes to have rolling contact with the peripheral portion of the bore, and l cutters rotatably supported by the body between said pairs of legs to rotate about downwardly and slightly forwardly inclined axes, the last mentioned cutters having annular scraping edges at their lower ends contacting the bottom wall of the well, and reaming teeth of longer efiective diameter than the lower portions of saidcutters JOHN H.