US2267833A - Well bit guide - Google Patents

Description

l De@ 30, 1941- 'r'. E. MCMAHAN 2,267,833,l

WELL BIT GUIDE Filed Feb. 9, 1940 r ff L I l ci 5 'r Pinnacle-Beendet,time

zasnsssr j WELL-Britannia' Thomas IMcMali'an; Fellows,(}alif. Application1February.9;1940;. Serial No. 318,086

inven tion :reiatesitc fwellffdrilli ticularly 'effectiveifguidesf orsf-.well-.-dril1ing bits.

Deepgwells'fsuclhlfasso swelles-andi gas. wellsusuallyshaveoffse c .-noneverticalacr-:crooked-.pon Whenafagdrillingfstool.l orcbit :lsffrun' into aA Well;` ont.. thee-lewe V`endst'ofythe.vdrilling; string` it "thecrooked?ori-offset. parts" rea-king.: away for. scarring itcustorn'aryp in: the rotary' methodiofiwelldrilling.toemployia' mud laden;

performing iotlierffunctionsformsa layer or'cake unconsolidated earthformationse-areencountered special rotar'yfmudis @usedfiwhich penetrates the formatlonzrto-;provide-rfa1;:betterrseal and "coating-5 y onrthezwelliwalli'andfthxsvprevent'caving ofthe loose 'l formation; Wlien: af drilling-f.A bitv 1 movlngi downwarrlly-.fin'vl arwelliscars:or; carriesaway `the@ Inudr: cake-1- from; theewell? wallftliee foundationi` oft'err breaks; looses and-f caves; in" behind z the bit-l'- causingrgconsiderabletroubler. The. mudlayeror 25 ,alli oftenf'faccumulates: L. on f cake fzf rom :the Vwell the f well'. bitrasthecbit s." run t into f. the '-,welL-L and mudsf-,unorf-'r balls'rfup theffcutting Iparts aso that the vbit cannot operatefeiectivelwwhen it reaches.l

the; bottom. of the awelllf.

It "is ran: object"v of athis-invention to providea well .bit-guide thatspreventsfthev bit from scar-i ring; disturbing:orf-,scrapingawayathel f mud filter cake=on the. ,wellfwallf whenzthe bit: is -rlowered into rthefvvell, and that-prevents: mud`Av from'th'e well wall 'from ,accumulating'onthe cutting .-parts.

Another -zobject'tofs/this :invention .isf-to :provide the: mudgfiilter:cakef from:` the..;well` wall L in the eventzifit lengages the -wa'llas.thebitipasses downthe :W en.

throughfanfol-set,noneverticalor crooked partof Another; objectief `:"thfisn'nvention'z'is Ato provide easily-.f and."quickly;I applied ofthe i bit' when the.

free circulations ofi fluidi-iithrough .the drilling string and bit and th'at does YnotV interfere with. orma-teriallyr-delay;thefdrillingfaaction1of the bitf wheni the-bit reachesffthef-b'ottom" of-:the .welll Anotlernobjecttof-thisf-invention'aisr-to provide' a" bit guidef of the'vcl'iaracterH referred. toA that ngtoolsxand-a relatesi f. morefparticularly to fshoeseor `guides:` for is readily broken up, drilled up, dissolved, or reduced to fragments when the bit is put into operation at the bottom of the well. I

Another object of this invention is to provide l' a friable, frangible or Adrillable bit guide formed of va material having a low specic gravity or a specic gravity comparable to that of the drilling iiuid, so that its fragments or cuttings are quickly flushed from the ,well by the circulation fluid yemployed in the usual drilling operations.

Another object of this invention is to provide a. bit guide of the character referred to that may be easily and inexpensively constructed for use gnt'spractically all types and forms of well drilling A further object of this invention is to pro- Avide abit guide ofthe character referred to that isV` easy to install and that is simple and inexpensive to manufacture.

The various objects and features of my invention will be fully understood from the following detailed description of typical preferred forms andv applications ofv the invention, throughout Ywhichdescription reference is ma'de to the accompanying drawing, in which:

Fig; 1 is a side elevation of a typical drag lbit for'use in the rotary method of well drilling equipped with one form of guide of the invention. Fig. 2 is an enlarged, horizontal detailed sectional view taken substantially as indicated by line^-22 on Fig. 1. Fig. 3 is a side elevation of a roller bit or rock bit for use in the rotary method of Well drilling provided with another form of guide of the invention. Fig. 4 is an enlarged, horizontal, detailed sectional view taken as indicated by line 4-4iof Fig. 3 and Fig. 5` is an enlarged fragmentary sectional View illustrating an alternative means for securing a [guide to abit. f

The bit guides of the present invention may be varied -and modified greatly in construction, design and materials to adapt them for use under different conditions and on bits of various types. .Inv the following detailed disclosure I will describe typical forms and applications of the invention, it being understood that the invention is not to be construed as limited.` to the particular forms or applications about t be described, as itvbroadly contemplates the' provision of a guide formed for attachment to a wellbit, shaped to prevent the-bit from breaking XNaway or disturbing the mud cake on the welltwall when the.

otherwise destroyed when the bit is put into operation.

In Figs. 1 and 2 I have illustrated a rotary well drilling bit of the drag type equipped with one form of guide of the invention. The bit in Figs. 1 and 2 comprises a body I0 secured to the lower end of a rotary well drilling string S and blades II projecting downwardly and outwardly from the body I0. In the particular case illustrated there are four substantially equally spaced cutting blades II. The blades Il have sharpened or bevelled lower parts tion at the bottom of the well bore and have substantially vertical outer edge I3. Circulation ports I4 are provided in the lower end of the bit body III to discharge the circulation fluid or rotary mud.

The bit guide shown in Figs. 1 and 2 may be said to comprise, generally a application to the bit, and means I6' for attaching the body I to the bit.

The guide body I5 is designed for ready attachment to the well bit and is formed to prevent the cutting blades II and other parts of the bitA from injuring the mud cake layer on the wall of the well when the bit is run down through the well. The guide body I5 may be varied greatly in construction and conguration without departing from the invention. In the typical case lillustrated the guide body I5 isa generally annular or tubular element having a continuous annular side wall. The upper and lower ends of the tubular or annular body I5 are open to permit a free movement and flow of iiuid through the guide.` As illustrated the interior of the guide body I5 may be substantially uniform in diameter. The exterior of the guidebody I5 is shaped to assure the downward movement of the bit and guide through the well with a minimum of injury to the well wall. The upper portion of the guide body I5 may be generally cylindrical while the lower portion or major portion of the guide body is tapered downwardly and inwardly or is provided with a surface I1 downwardly and inwardly.

curved surface II may extend to the lower ex-' tremity oi the or merge with tapered or rounded surface I1 is preferably, though not necessarily, smooth and is such that its engagement with the wall of the well results in a minimum of damage It will be seen that the tapering or curved surface I'l may wipe or slide along the well wall without scarring, breaking loose or disturbing the mud cake.

The upper end of the guide body I5 may be shaped to conform to the lower portion of the well bit. In the construction illustrated the upper end I8 of the body I5 is iiat and generally horiraontal and is provided with spaced notches I9 for receiving the lower end portions of the bit blades II. The notches I9 may be shaped to rather accurately conform to the active lower parts I2 of the blades Il. The guide body I5 is proportioned so that its external surface or at least the external surface o! its upper portion is outside of or flush with the outer edges I3 of the cutting blades I I. This proportioning of the body I5 positively prevents contact of the cutting edges I2 with the wall of the well when the bit ismoved through the well. It 'may be preferred to form or shape the lower part of the guide body I5 in such a manner with its engagement guide body I5 and may approach I2 for acting on the formathat rounds or curves,

This tapered or, 45

with the bottom o the well prevents turning of the guide. Thus, as illustrated in Fig. 1, the lower end of the body I5 may have serrations or teeth 25 for engaging the bottom wall of the well to resist turning of the guide body lI5 when the bit is set down and rotated.

In accordance with the invention the guide body I5 is frangible, friable, drillable or soluble to be readily broken up, shattered, drilled up or dissolved when the bit reaches the bottom of the I well and, isput'into operation. Considering the guide body I5 for invention in-its broadergaspecttheguide body I5 may be constructed of anymaterial that is brittle, crushable, or iriable so that it breaks up when the bit is set down on the bottom of the well,

vvthat readily cracks, parts or divides into reasonably small parts when the bit is set down on the vbottom of the well, that is softer than the ma- `terial of the bit to be readily drilled up when the bitis rotated at the bottom of the well,

or that is soluble in the water or other duid in the well to readily dissolve so that it does not interiere with the bit operation. The material of which the bit body I5 is .formed I nay, of course, have twol or more ofthe characteristics mentioned. Further, it maybe preferred vto construct the body I5 of two'or more materials having the selected characteristics. It is contemplated that the guide body I5 be formed of wood, phenolic compositions such as Bakelite and-other plastics, ceramic materials, cement, drillable, metals such as aluminum, aluminumalloys, copper, copper alloys, pewter, Dow metal or cast iron, rubber,

rubber compositions with or without fabric,vnatu ral or artificial stone, papier mch, pressed iiber, glass.

` or otherwise shaped or fabricated. While I have the internal wall of the body. The

to the mud iilter cake. v

shown the guide body I5 constructed in one piece it is to be understood that it may be sectional or fabricated from a number of suitably con-` nected sections. v I

The means I5 for securing or attaching the guide body I5 to the bit is preferably such that theguide may be quickly secured in` itsopera The securing means I6A tive position on the bit. may be varied greatly-without departing from the invention. In the construction being described transverse openings 2I. are formed in the bit blades II and openings 22 are formed in the body I5 to register with the openings 2I-. `Rods or pins 23 arepassed into the openings 22 to extend through the openings 2l; -The pins 23 engaged in the openings 2| and 22 dependably secure the guide body I5 to the well bit. When thebody I5 is arranged in its proper position on the lower end of the bit the openings 22 are aligned with the openings 2| to receive the pins 23.V Where the character of the material, of which the body I5 is formed, permits,the body may be secured to the bit by molding or casting the body on the bit. If the body I5 is formed of or includes rubber or other resilient material, the resiliency of the material may secure the guide to the bit. In other cases the guide may be cemented or adhesively secured to the 'bit or maybe welded, soldered or brazed to the'bit.

or soluble material capable of being shaped, by casting or working and that ishwater or oil In the use or operation of the'bit guide ill trated in Figs. 1 and 2, the body I3 is engaged against the lower end of the bit to have the notches I3 receive the lower parts of the blades The pins 23 are then passed through the openings 22 to cooperate with the openings 2|. 'Ihis attaches the guide to the blt and conditions the assembly for running into the well. The blt is run into the well on the lower end of the string S in the usual-manner. During the downward passage of the blt through the well the guide body directs or guides the bit and prevents the bit parts from contacting or injuring the lining or mud cake on the well wall. The sloping or curved guide surface |1 may engage the wall in crooked or 'set parts of the well to guide the bit through such well portions. The engagement of the guide surface |1 with the lining or mud cake on the well wall does not result in detachment, scarring, or scraping of the lining or mud. The guide body I5 projecting downwardly from the lower end of the bit and'covering or en-l gaging under the cutting parts positively prevents the cutting jparts from digging into or scraping the wellwall.. The bit may be run to the lower end of the well without digging into or injuring the side wall ofthe well at any point. When the bit has reached the bottom of the well it is set down, that is, the weight, or a portionof the weight of the drilling string S is applied to the bit. This weight is, of course. transmitted to the bottom of the well through theguide body I5. Where the body I5 is formed of friable. frangible or brittle material of the character referred to above, the weight imposed on the guide body may cause the body to break or crumble.

When the bit has reached the bottom of the well and is in condition to begin the drilling operation the string S is rotated with a suitable feed pressure or load applied to the bit. The bit operated in this manner soon crushes or drills up the guide body I5. If the bit body I5 is formed of a drillable material such as a soft metal, rubber, fibrous materials, stone, or the like, the cutting parts of the bit rapidly drill the guide into small fragments or particles. When the body I3 is constructed of a brittle, friable, or frangible material such as glass, Bakelite, cement or the like the rotating bit soon breaks the guide into small fragments. The circulation uid discharged from the ports |4 of the well bit flushes away the particles of the broken up or drilled up guide and the circulation fluid flowing upwardly in the well carries the guide fragments to the ground surface. 'I'he guide effectively guides the bit through the Vwell to its operative position and is then quickly and easily broken up or drilled up,- leaving the bit exposed for free operation. The guide in addition to preventing the bit from injuring the well wall prevents mud from the well wall from accumulating or gathering lon the cutting parts of the bit and the bit is clear and ready for operation when the guide is broken up or drilled up.

The well bit illustrated in Figs. 3 and 4 comprises a bit -body 30 securedl to the lower end of the drilling string S and provided with sets of downwardly 1 projecting legs 3|. Outer roller cutters 32 are rotatably supported between outerpairs of legs 3| to cut vthe well bore to gauge and to form the outer portion of the well. A series of cross cutters or inner cutters'33 is rotatably supported between another set or pair of legs 3| and serve to drill away the inner portion of the well ject downwardly beyond the legs 3| and the other body parts to act freely on the formation at the bottom of the well.

The guide of the invention illustrated in Figs.

3 and 4 may be said to comprise, generally, an guide body 34 and means 35 for securing the guide body to the well bit.

The guide body 34 is constructed and shaped to be easily applied to the well bit and to prevent contact of the rollers 32 or 33 with the wallof the well. The guide body 34 may be varied in shape and construction depending upon the kind of material used. In the case illustrated the body 34 embodies a minimum of material to be light in weight and cheap, and yet has ample strength. The body 34 includes a pair of aligned horizontally projecting wings 36 for engaging under the cross or inner cutters 33. The wings 3B have concave upper sides to receive the pro- Ijecting lowerportions of the cutters I3 and have convex or conforming under sides. The outer jacent ends of the inner legs 3|.

bore. The toothed roller cutters 32 and 33 pro- 73 ends of the wings 33 project beyond or are ilush.

with the outer ends of the cutters 33 and the ad- Rather heavy or thick parts 31 extend outwardly at opposite sides of the wings 36 and join substantially vertical legs or wings 38. 'I'he upper sides of the vertical wings 33 are concaveor provided with notches 33 located and shaped to receive the lower parts of ',the cutters 32 and the outer legs 3| of the bit. The outer surfaces of the-Wings 38 are beyond or at least flush with the outer ends of the cutters 32 and their legs 3| to prevent these parts from contacting the side wall of the well bore when the bit is run into the well.

The outer surfaces 4D of the wings 38 are preferably convex and.) as best illustrated in Fig. 3 of the drawing, slope or curve downwardly and inwardly with respect to the longitudinal axis of the bit. These convex curved surfaces 4U effectively guide the bit through offset or crooked portions of the well while preventing the bit from gouging into or injuring the well wall. A transverse web or brace 4| may extend between and connectv the spaced wings 38 to strengthen the construction. As shown in Fig. 4 of the drawing the bracing web 4| may be quite thin. The web 4| operates under compression to brace or support a wing 38 when the wing strikes or engages against the side wall of the well bore. The supporting or bracing web 4| may or may not extend downwardly to the lower ends of the Wings 33. Spaced ports 42 may be provided in the parts 38 to permit a free discharge of the circulation fluid through the guide. The guide body 34 oonstructed as just described may be an integral casting l,or may be fabricated from several pieces. A In Figs. 3 and 4 of the drawing the means 35 for attaching the guide to the bit includes flexible elements for binding or tying the guide to the bit. These flexible elements may be rubber bands, rope, cords, straps, or wires. In the case illustrated the flexible securing elementsv are in the nature of wires 43. The wires 43 have their lower ends fixed to the guidebody 34 .and the upper portions of the wires are adapted to exe tend about selected parts of the bit. As shown the wires 43 may pass upwardly around the bit to engage over the legs 3| and the end portions of oppositely extending wires 43 may be twisted together as at 44. The wires 43 may be cast in the guide body 34 or may be secured to the guide Ibody by pins, screws, or the like.

The guide body 34 illustrated in Figs. 3 and 4 broken up, crushed, drilled up or dissolved when the 'bit has reached the bottom of the well. The guide of Figs. 3 and 4 may be constructed of any suitable or selected friable, frangible, drillable or soluble material. For example, it may be formed of any of the materials mentioned in the description of the guide body I5. 'I'he securing means I6 illustrated in Figs. l and 2 of the drawing may be utilized to secure the guide body 34 of Figs. 3 and 4 to the bit or the wires 43 illustrated in Figs. 3 and 4 may, if desired, be employed to secure the guide body i to the bit.

In employing the guide of Figs. 3 and 4 the guide is secured to the bit when the bit is to be run into the well. The guide is merely arranged in the proper position on the lower end of the bit and suitably secured in place by the wires. The bit is then run into the well on the lower end of the string S. As the bit passes downwardly in the well the guide directs the bit and may prevent the bit from contacting the side wall of the well. The surfaces 40 and other parts of they guide body 34 may wipe against or engage the mud cake on the wall of the well without gouging or injuring the same. The guide prevents the roller cutters 32 and 33 and the supporting legs 3| from scraping against or digging into the well wall and is effective in preventing mud from the well wall from gathering on the cutters and accumulating on the bit. When the bit has reached the bottom of the well a suitable load or. feed pressure is applied to it and the string is rotated in the usual manner. The pressure applied to the bit breaks up or shatters the guide body 3| when the body is formed of brittle frangible or friable materials, and the drilling action of the bit quickly drills up the guide when the guide is formed of wood, drill'able metal, or otheni drillable material. The fragments of the broken or drilled up guide are flushed from the well by the rotary mud or circulation fluid discharged from the bit. When the guide has been broken up, crushed, or drilled up the bit is exposed for freeoperation.

I The body l5 or 34 of the guide, or parts of the saine may be constructed of characteristically colored material or materials so that returns of the broken up or drilled up guide are easily recognized in the rotary mud or drilling Huid discharging from the well. This provides an accurate means for determining the time required for the circulation to return from the Well bottom to the ground surface.

Fig. 5 of the drawing shows an alternative means for attaching or xing a guide of the invention to a well bit. The construction of Fig. 5 includes spaced spring clips 50 whose inner ends are embeddedw in or otherwise fixed to the body 5| of thel guide. As illustrated the embedded inner parts of the fingers 50 may be bent or curved to be better. anchored The outer parts of the spring fingers have inturned lugs 52 for engaging over a surface 53 of a bit part 54. The spring ngers 50 may automatically engage the bit part 54 to secure or to assist in securing the frangible or drillable guide to the bit. The attaching means of Fig. 5 may, if desired, be employed in connection with any form of guide of the invention.

Having described only typical preferred forms and applications of my invention, I do not Wish to be 1imited`or restricted to the specific details herein set fotig, but wish to reserve to myself any variationsbr modifications that may appear' to those skilledsin the art or fall Within the scope of the followirigclaims:

Having described my invention. Ivclaixn;

guide comprising-a body shaped tofreceive the lower portions of said roller, cutters to preventl the cutters vfrom contactingrthe'wall of they welly when the tool is run `lntothe well.v and. means for securing the-,body to the-tool, ythe'body-beingv frangible to be readilybroken-upA or `drilledup by the tool when thel tool'zis operated in: the well.

2. A guide for a welldrilling toolhaving cutdownwardly and inwardly` tb guide the tooll through the well.` and means for attaching the.

body to the tool, the body being-formed of drillabie material to be driued-upby said ycutting i parts when the tool is operated'in the well.

3. Aguidefora rotary well'drilling-bithaving fluid discharge means, the` guide comprising-fa guide body to be arrangedxon the/lower endof the bit and including portions for covering'theactive bit parts to preventthem ,fromdigginginto the side wall of the well whenthe bit isbeing rundown through the well, saidbody having a.

passage for maintaining said fluid discharge means in communication with the well, the guide body being formed ofdrillable materialoflafspecific gravity comparable withsthat ofthe drilling the tool and including upper portions recessed 'to receive said roller cutters, and alower portion tapered downwardly and'inwardlyto guide the-Y tool and body downwardly throughthe well,v and;` means for attaching thea-bodyzto'the tool, the. f body being formed ofy drillable material tov be` readily drilled up by thetool4 when the` tool -on its lower end, the guideincluding'a tubular v"guide body having recesses in its upper end for the exposed parts of the roller cutters and designed to prevent the cutters from digging into the wall of the wellwhenthe bitxis lowered into the well, and means for facilitating the attachment of the body to the bit.A

'7. A guide for a rotary 'rock bit-.having roller` cutters exposed at its lower end, the guide comprising a guide body to be arranged at the lower end of the bit, the body being formed of drillable material and including wings` for'tting under the exposed portionsfof theV cutters, anda web extending between the wings.,

8. A guide for a rotary welldrillingtool having a cutting vpart and fluid discharge means, thel guide comprising a body ,having a `portion kfor agences covering the lower side o! the cutting p'art and shaped to guide the tool through the well without digging into the well wall. the body having a passage for maintaining said -Iiuid discharge means in communication with the well bore. and means for securing the body to the tool, said means including a pin received in openings in the tool and guide body.

9. A guide for preventing the cutting parts of a rotary well drilling tool `from injuring the wall o1' the well when the to'ol is lowered through the well, the guide con'iprising-a. guide body to be arranged at the lower vend of the wol and comprising parts for underlying and generally conformv ing tothe cutting parts and presenting guide surfaces for contacting the wall of the well to prevent injurious contact of the tool with the well wall, the body and its said parts lying entirely within the circle dened by the outermost portion of the tool when `the tool is rotated, and means for securing the body to the tool.

10. A guide for a well ldrilling tool having an exposed roller cutter at its' lower end, the guide comprising a body o! drillable material arranged at the lower end oi the tool and having a portion generally conforming to and protruding below the exposed lower side oi. the roller cutter to prevent the cutter from contacting the wall o! the well when the tool is lowered through the well, and means for securing the body to the tool, the peripheral portion of .the body being shaped to leave generally vertical passages for the ow of iluids;

11. A guide for a well bit having. cutting parts A on its lower end and a circulation opening comprising a guide body for arrangement on the lower end of the bit to cover its cuttingparts, the body having a rounded lower end for guiding the bit downwardly in the well and having a port for maintaining said opening in communication with the well, andmeans for securing the body to the bit, the body being formed of a readily drillable material to' be drilled up by the bit.

VTHOMAS E. McMAHAN.

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