US2654576A - Expansible rotary drill bit - Google Patents

Description

Patented Oct. 6, 1953 UNITED STATES ram OFF EXPANSIBLE ROTARY DRILL BIT Archer W. Kammerer, Fullerton, Calif. Application August 18, 1950, Serial No. 180,168

9 Claims. 1

The present invention relates to rotary drill bits, and more particularly torotary drill bits of the type embodying cutters that are shiftable between retracted and expanded positions, to drill a hole below a casing string larger in diameter than the inside diameter of the casing string through which the bit is lowered.

In my prior Patent 2,466,991, a rotary drill bit is disclosed having cutters that are expanded outwardly to their full enlarged drilling diameter before any drilling weight is imposed on the cutters. After their expansion, a downward thrust on the drilling string locks the cutters in their outward expanded position and prevents their retraction.

The type of lock device disclosed in the above patent may urge the cutters outwardly from retracted, or partially retracted, positions in the event drilling weight is imposed on the bit before the cutters have been expanded to their maximum position. The operator may not be advised of the fact that the cutters have not been moved to their maximum expanded position, since the Wedging or expanding force imposed on the cutters would enable them to support the drilling weight. Accordingly, the lock device would be the instrumentality for expanding the cutters, which would result in the imposition of loads on such lock device that the preferably should not carry. Moreover, an undergauged hole might be produced along a certain length of the well bore.

In certain types of hole enlarging operations, such as the increasing of the well bore size along only a portion of its length, the cutters may be pulled upwardly into a relatively small diameter Well bore portion, as would occur in the event the kelly at the top of the hole were to be removed from the drill string. Thereafter, upon reconnecting the drill pipe and kelly, and lowering of the drill string and bit, the lock device might tend to urge the cutters outwardly in the smaller diameter hole, merely as an incident of the lowering movement of the drill string for the purpose of relocating the bit back into the enlarged portion of the well bore. Such premature outward expansion of the cutters is not desired.

Accordingly, it is an object of the present invention to provide a lock device which does not tend to expand the cutters outwardly, at least until such cutters have been expanded to a substantial extent by some other means.

Another object of the invention is toprovide a locking arrangement in an expansible rotary drill bit which will exert substantially no outward expansive force on the cutters until after they have moved outwardly beyond a predetermined hole drilling diameter, but which can thereafter forcibly urge the cutters outwardly to their maximum hole drilling diameter.

A further object of the invention is to preclude any downward forces imposed on an expansible rotary drill bit by the drill string from urging the cutters outwardly, unless such cutters have previously been expanded beyond a certain hole drilling diameter; so as to offer assurance that the cutters would be resting upon a substantial formation shoulder in the well bore before any appreciable drilling weight can be imposed upon them. Because of the arrangement noted, the downward drilling weight would merely slide the entire tool down the hole without enlarging the latter, in the event that the cutters are in their substantially fully retracted position.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of a Figure 1 is a longitudinal section through an expansible rotary drill bit disposed within a well bore, with the parts of the drill bit in retracted position for lowering in the well bore;

Fig. 2 is a view similar to Fig. 1 of the drill bit, with its parts in their fully expanded'position;

Fig. 3 is an enlarged somewhat diagrammatic view through the lock port-ion of the bit, with a cutter in fully retracted position;

Fig. 4 is a View similar to Fig. 3, illustrating the locking device preventing retraction of a cutter from its maximum outward expanded position;

Fig. 5 is a view similar to Fig. 3, illustrating the coaction between the lock device and the cutter device when the latter occupies intermediate positions between its fully retracted and fully expanded positions.

As shown in the drawings, the expansible rotary drill bit A is attached to a string of drill pipe B by means of which it is lowered in the well bore to the point at which enlargement of the bore hole is to commence. The bit is capable of enlarging the bore hole by producing and operating upon a formation shoulder C, as hereinafter described.

The upper end of the bit consists of a driving mandrel I I whose upper pin I2 is threadedly connected to a sub I3, forming the lower end of the drill pipe string B. This mandrel includes an upper kelly or drill stem member I4 slidably splined to. the main ..body I5 of. the bitin any suitable manner, suchaszdisclosediin my Patent 2,466,991. The mandrel I4 has a limited'range of longitudinal movement within the body, its. upward movement being determined by engagement of an external shoulder H1: their-kelly; with a retainer ring I! suitably secured to the upper end of the body I5, as by the'us'e of weldirlg material I8.

The body [5 has a plurality of expansible parts mounted on it, comprising opposed cutter-sup porting members I9, I9 pivotally carried on pivot or hinge-pins 2 21' suitably'secured:to the body: Each cutter supporting member: consists; oh a; depending leg 23 havinga:bearingsupportingipin: 24 inclined inwardly and dhwnwardly' and: on". which is rotatablymounted'ia roll'er side cutter 2'5. Anti-friction roller and. ball-bearing e1e+- ments 26 21 are preferably"placedzbetweenieach: cutter 25 and bearing pin 211; therroller bearings 26- transmitting: radialv thrusts; and the ball" bearings 21 both radial and axial thrusts.

Each cutter supporting: member, i=9" also ine cludes' an upwardly extending: arm 30' against which an elastic expander 31f bears: This ex.- pan'der is in'the'form of: a c'ompressed coil spring received within a retainerpocket 32 in the body I5, exerting its forceagainst the arm. 30 and tending to swing'it inwardly and :thus: urgethe. cutter 25 on the other side. of the: fulcrum pin: 2| in an outward direction. The extent of this: outward movement-is limited lay-engagement of stop shoulders 33; 33. on oppositezsides: of. the. cutter supporting: member: [.9 with cooperable body stopshoulders: 34;:34;

After. each cutter 25' has" been expande'dqoutr wardly by its cooperable expander'spr-ing-ifirltoi 5;) the maximum extent, it-:cane be lcckedin. this position by a tubular member: 35' of the mandrel. I I, which is piloted in the kelly l'flrandsisprovided. witha lock portion e1. Ehelatter is; movable; from an upper positionin transverse alignment with inner supporting member recessespafi perv mitting retraction of the cutters; to: alowerposition opposite lugs-'31. formed: on and projecting inwardly from the supporting member: legs: 23; preventingqretraction of the-cutters 25.

The tubular member 35- is connected; in. swivel fashion to the kelly [4 to permit relative arcuate or rotary movement therebetween. However. the kelly and tubular member are movable together for longitudinal movement. in-both direc-- tions. All this is accomplished by providing a shoulder 56 on the tubular member containing an external toroidal raceway 51 receivingbearing balls 38 that are also ridable in an opposed; internal raceway 39 formed in the kelly I4. The balls 33 are insertable through a hole 46 extending through the kelly shoulder" I5, and, after having been mounted in place within. theraceways 57, 39, this hole can be closed by a suitable: plug 4! which is prevented from moving out of the hole by the main body I5 of the bit.

The upper portion 35a of the tubular member 35 is piloted within the fluid passage 42 through the kelly I I, and has itsend'3'5b flaring upward.- ly and outwardly to. guide a. ball 4.3,. or .ecrra sponding element, into the central passage 350 through the tubular member 35. Fluid pumped down the drill string B will flow through the kelly pin [2 and into the central passage 350. It is prevented from flowing around the exterior of the tubular member 35 by a suitable packing 44 disposed between the upper portion 35a of the tubular member and the kelly It; adjacent the upper end of the tubular member shoulder 55.

The arrangement betweenlthe tubular member 35 and kelly I4" is such" that" both downward and upward movement is transmitted between the kelly I4 and tubular member 35 from one racewayilon 39, through the ball bearing elements 38', to the other raceway 39 or 51. In this theakelly I4 and tubular member 35 are caused to mo.vel iointly in both longitudinal directions, but they are able to partake freely oi relativamovement therebetween.

The mandrel II is normally held in its upper positionwith respect to themainbody I5..of the bitiand the supporting; membersl I9. by a. helical, retractor spring 46 encircling the tubular member. 35, with .its. upper. end. engaging. the. mandrel.

shoulder strand its: lower endengaging aspring, seatAB resting onthe body If. This spring seat.

is also serves as anupperbearing guide forv the tubular mandrel. member 35,. whose lower. end is slidable withina lower. bearing guide 49, below the lugsv 31,- which. isv integral. with. or secured. to the main bodyof. thebit. The, two guides. 48,. dilform aspaceditwo-poi'nt support for the mandrel" member 35T'and' assist it inresisting. inward movement ofjthelcutter legs, Z3v toy I retracted position during the reaming or cutting operationl Circulatingfl'uid canpass downwardly through the stringof drill pipe B and through the -tubular mandrel. II; forei'ection from it'sl'ower discharge nozzle 35d and. onto the cutters, 2,5, to cleanse. them of cuttings. and. flush thev latter from the. drilling area to thetopot the wellbore. This circulating fluid. is also availed v011$ to unlatch the cutter. supporting,.members I'BLin the. event it is desiredto hol'djthem positively in re tractedposition.

The cutters may be retained initially in ret'racted, positions against the, expansive forces of the springs 3| by meanso a trip device device includes a holding plate or member '18 secured to, the lower end'of a central rod" whoseupper; end projects into the tubularmember passage 350.. Ahead is secured to the upper end of the rod, which has substantial clearance there-around, in order ta allow fluids to pass upwardly into the central passag 35c and into the drill string B, The holding member I8 has spaced holes 82. in its outer portion for receiving the lower ends 29a of ball. bearing plugs or pins 2'9 which hold the cutter bearing balls 21 in operative position.

When the holding device it is disposed over the pins 29, the cutter supporting members I9 are prevented from expanding under the influence of the springs 35-, thereby holding the cutters 25" in retracted position. It isto be noted that the pins 29' are inclined initially in a downward and outward direction, so as to prevent the holding member 18 and the rod 19' connected thereto from moving downwardly until purposely released, which downward movement would allow outward, expansion of the cutters 25. Such: release can occuras a result of fluid pressure-acting downwardly on the'ball 43, which can rest on.

the head 80.

.Durineloweringoithtin ttina tool tozthe point This 1 at which the reaming operation is to begin, the holding device I8, I9 retains the cutters 25 in retracted position. During this lowering operation, fluid may flow upwardly around the holding device rod 79 and around the head 80 into the tubular member passage 350.

When the point in the well bore has been reached at which the reaming operation is to begin, the pumps at the top of the well bore are started and drilling fluid pumped down the drill string B. The ball is then forced down through the passage 35c onto the head 89. Since the di ameter of the ball is preferably equal to the diameter of passage 350, it substantially closes the passage to downward flow of fluids, which allows the pumps at the top of the well bore to exert a pressure on the fluid in the drill string B and tubular member. This pressure acts downwardly on the ball 15, which correspondingly exerts a downward force on the holding device I9, 18, shifting the latter in a downward direction off the pins 29, and the ball 75 and rod 1!! completely out of the passage 350. The pins 29 are thereby released, allowing the springs 31 to expand the cutters 25 outwardly, while at the same time the passage 350 is free from restrictions, which allows fluid to be pumped through its lower nozzle 35d onto the cutters.

In the operation of the device, the tool A is mounted on the lower end of the drill string B, with its parts held in retracted position by the latch or trip device l8, #9, as shown in Fig. 1. In this position of operation, the compressed retractor spring (it holds the mandrel H and its kelly It in an upward position with respect to the body I5, as determined by engagement of the kelly shoulder It with the body retainer ring l7. With the mandrel in this position, its lock portion 41 is elevated above the lugs 37 on the cutter supporting members within the inner recesses 36 in the supporting members, which permits the latter to be held inwardly against the action of the expander springs 3|.

The tool is lowered through the well casing, and upon reaching the position in the well here at which the drilling operation is to begin, the pumps are started at the surface of the well bore, the fluid under pressure in the drill string and bit A forcing the trip device 73 off th pins 29, releasing the cutter supporting members I9 for outward expansion under the influence of the springs 3|.

The drill string B is then rotated to rotate the main bit body I5 through the splined .kelly and body connection, the expander springs 3i forcing the arms 3!! inwardly and the cutters 25 outwardly against the formation. Rotation is continued without moving the drill string longitudinally until the side cutters 25 enlarge the diameter of the hole to the maximum extent, as determined by the eventual abutting of the supporting member stop shoulders 33 with the companion body stop shoulders 3 Thereafter, the drill string is lowered to cause the formation shoulder C, produced in the well bore by the cutters 25 under the action of the expander springs 3|, to support the cutter members I9 and body I5, and prevent their downward movement.

Since the body I5 cannot move downwardly, drilling weight imposed on the drilling string 13 shifts its connected mandrel I I downwardly within the body I5 against the action of the re- I9, being received i tractor spring 45 until the lower end 5t of the kelly I4 engages the upper spring seat and guide 48. This downward movement also shifts the tubular member 35 downwardly, because of the interlocking ball thrust bearing 31, 33, 39, to position the mandrel or tubular member lock portion opposite and in alignment with the lugs 31 on the inner portions of the cutter supporting members I9, providing a positive look by preventing inward movement of the cutters. So long as down weight is imposed on the drill string B, and the cutters 25 rest on the formation shoulder O, the cutters are prevented from moving inwardly by engagement of their lugs a? with the mandrel lock portion 41. It is also to be noted that further outward movement of the cutters beyond the predetermined maximum reaming diameter is prevented by contact between the supporting member shoulders 33 and the body shoulders 34, through which the drilling weight is transmitted to the roller cutters 25, thus relieving the hinge pins 2| of this load.

Drilling is continued by rotating the drill bit and imposing the proper drilling weight on the cutters to cause their removal of the formation material and reaming of the hole in a downward direction for the desired extent or length. When the drill bit is to be retracted and removed to the top of the well bore, all that need be done is elevate the drill string B, which moves the side cutters 25 above the formation shoulder C, and permits the retractor sprin 46 to press downwardly on the body I5 and move it, together with the cutter supporting members I9, downwardly with respect to the mandre1 II. This action re-positions the mandre1 lock portion Ill opposite the supporting member recesses 35 and above their lugs 31, because of the ball bearing coupling 38, permitting inward swinging of the cutters 25 and their supporting mem bers I9 when the tool passes back into a well casing (not shown), upon elevation of the drill string 13. The cutters 25 and their supporting members I a will ride the wall of the casing during elevation of the string until the tool is removed from the top of the well bore.

As noted above, after the springs 3I have expanded the cutters 25 outwardly to their full hole enlarging position, the mandrel II can be lowered to dispose the lock portion 4'! behind and in alignment with the cutter s pporting member lugs 37!. The outer surfaces 41a on the lock portion of the mandrel will en age the inner surfaces 37a on the lugs, to preclude retraction of the cutter supporting members I9 and their roller side cutters 25. These surfaces 41a, 31a are preferably flat, and may be substantially parallel to the axis of the drill bit. However, it is preferred that the outer lack or retainer surfaces lla on the lock portion of the mandrel and companion inner surfaces 31a on the lugs 31?, when the cutters are in their maximum outwardly expanded. position, be inclined slightly to the vertical, converging toward the axis of the drill bit in a downward direction. Such slight tapering will result in a slight wedging action of the mandrel lock portion 4? within the cutter supporting members I9, and will. tend to hold the retainer surfaces 41a, 31a snugly in engagement with one another, thereby avoiding play or looseness between the parts.

Before the springs 3| have expanded the cutters outwardly from their initial retracted positions to a substantial extent, any down weight or drilling weight imposed on the drillin string B and; the mandre1 II cannot have any effect retainer means in holding engagement with said cutter means, said contactable port-ions, when in contact with each other, being positioned relative to each other such that the resultant force exerted between the portions extends in a direction parallel to the axis of said mandrel, whereby said contacting portions do not urge said outter means outwardly.

2. In a rotary well drilling bit: a main body; cutter means mounted on said body and having an abutment member; means engaging said outter means for expanding said cutter means laterally outward; a mandrel slidably splined to said body and adapted for connection to a drill string; a retainer member on said mandrel movable with said mandrel in one longitudinal direction along said body into holding engagement with said abutment member to prevent inward movement of said cutter means from its outward expanded position; said retainer member and abutment member having portions contactable with each other, prior to full lateral outward movement of said cutter means, to preclude location of said retainer member into holding engagement with said abutment member, said contactable portions, when in contact with each other, being positioned relative to each other such that the resultant force exerted between the portions extends in a direction parallel to the axis of said mandrel, whereby said contacting portions do not urge said cutter means outwardly.

3. In a rotary well drilling bit: a main body; cutter means mounted on said body and having an abutment member; means engaging said cutter means for expanding said cutter means laterally outward; a mandrel slidably splined to said body and adapted for connection to a drill string; a retainer member on said mandrel movable with said mandrel in one longitudinal direction along said body into holding engagement with said abutment member to prevent inward movement of said cutter means from its outward expanded position; said retainer member having a lower transverse surface substantially normal to the axis of said mandrel and engageable with an upper portion of said abutment member which is inclined in an inward and upward direction.

4. In a rotary well drilling bit: a main body; cutter means mounted on said body; a mandrel slidably splined to said body and adapted for connection to a drill string; means engaging said cutter means for expanding said cutter means laterally outward independently of movement of said mandrel along said body; retainer means on said mandrel movable in one longitudinal direction along said body into holding engagement with said cutter means for preventing inward movement of said cutter means from its outward expanded position; said retainer means and cutter means having portions contactable with each other, prior to full latera1 outward movement of said cutter means, to preclude location of said retainer means in holding engagement with said cutter means, said contactable portions, when in contact with each other, being positioned relative to each other such that the resultant force exerted between the portions extends in a direction parallel to the axis of said mandrel, whereby said contacting portions do not urge said cutter means outwardly; said retainer means and cutter means having expander portions which are contactable with each other after partial lateral outward movement of said cutter means and prior to full lateral outward movement of said cutter means to urge said cutter means outwardly upon longitudinal movement of said retainer means along said body toward holding engagement with said cutter means; said expander portions being removed from the location of contact between said other contactable portions of said retainer means and cutter means.

5. In a rotary well drilling bit: a main body; cutter means mounted on said body and having an abutment member; means engaging said outter means for expanding said cutter means laterally outward; a mandrel slidably splin d to said body and adapted for connection to a drill string; a retainer member on said mandrel movable with said mandrel in one longitudinal direction along said body into holding engagement with said abutment member to prevent inward movement of said cutter means from its outward expanded position; said retainer member and abutment member having portions contactable with each other, prior to full latera1 outward movement of said cutter means, to preclude location of said retainer member into holding engagement with said abutment member, said contactable portions, when in contact with each other, being positioned relative to each other such that the resultant force exerted between the portions extends in a direction parallel to the axis of said mandrel, whereby said contacting portions do not urge said cutter means outwardly; said members having coengaging expander portions removed from the location of contact between said contactable portions for urging said cutter means outwardly, said expander portions being engageable with each other only after said cutter means has been partially expanded.

6. In a rotary well drilling bit: a main body; cutter means mounted on said body and having an abutment member; means engaging said outter means for expanding said cutter means laterally outward; a mandrel slidably splined to said body and adapted for connection to a drill string; a retainer member on said mandrel movable with said mandrel in one longitudinal direction along said body to place a longitudinal surface of said retainer member behind said abutment member to prevent inward movement of said cutter means from its full outward expanded position; said retainer member having a lower transverse surface substantially normal to the axis of said mandrel and engageable with an upper portion of said abutment member which is inclined in an inward and upward direction; said abutment member having an expander surface inclined in a downward and inward direction and leading away from the upper portion of said abutment member to be engaged by said retainer member to urge said cutter means outwardly when said cutter means has been par tially expanded by said expander means.

'7. In a rotary well drilling bit: a main body; cutter means mounted on said body and having an abutment member, said abutment member having an upper outer surface inclined in an inward and upward direction, as well as an expander surface extending from said upper surface and inclined in a downward and inward direction; means engaging said cutter means for expanding said cutter means laterally outward; a mandrel slidably splined to said body and adapted for connection to a drill string; a retainer member on said mandrel movable downwardly with said mandrel along said body to place a longitudinal surface of said retainer behind said abutment member to prevent inward m vement or'saidwutterrriam'from its fuireut- Ward expanded fib 'sitibh; sa'l'd f'i'} I'i having 'a lower transverse surracesiibs aintially normal to the axis ofsaid' 'Inafidfl'arid' engageable with the intersection of Said aliilt'rrihffiifaces when said Cutter means is insulistafitially its fully retracted positionfsaidiftainer mmfir having a bortidn between itslongitudinal surface and transverselsurfaee e'n'gageable with same;- pander surface to ii'rgesai'd 'cutte'r'me'a'ns out- Wardly, upon downwardmovemem of Saidmandrel along sai'd'bodyfwhen said cutter means has been parfiauyexpanded by said expander means.

8. In a rotary 'welfdrilling' bitz 'a' mambod cutter means mo'u'fited dnf's'aid body and hailin an abutmentmeinbrffilfovided with'an upper edge; means engaging'saidffitterhieafis for expanding said cu't'tenmeari's lat ally'foutwar'dfa mandrel slidabl'y 's'plined to saidway'anaaaaptd for conneotion'to'a drill smug; aretaiiier'niemher on Said mafidi"e1 ifi6liab1ewith aid ifiahdiel in one longitudinal 'di'reetionalong "said 5663 into holding engagement with said awfment member to prevent iriWard'nioven'rentof said amter means from' its 'dutwardsgpanaea Dos'ition; said retainer member havnigamwrtrafisverse surface" substantially; "mariner to the "aiii's 'f said mandrel and engagable in'll'n'e eontabt'withs'aid upper edge or 'saidfablutmnt membe Io'rior "to disposition of'said'retairier rii'nr'iber jl'idld'in'g engagement "with said abutment "member, to

12 transmit a 'i'esultantforde' b'etweensaidmembei-s having substantially no lateral" component tendiing to urge'said cutter means outwardly. v I

9. Ina rotary well drilling bitz'a'mai'n' body; cutter means mounted on said body andhaving anabutment member; means engagingsaid hue ter means for expanding said cutter means laterally outward; a mandrel slidably splined to saidfbody and adaptedfor 'eo'r'm' "t"o'n tof'a drill string; a"i"et-airier 'ifiinljronsald manarerm'evable 'withsaid friafidfrin ohje rehgituaifim d i-. rectioh 'alo'ngs dl ody toholdingerigamnt with said abutment me g tact With 'said' dg'effiriof'to "dispositioniof retainer'ihinbr 'ntb lriolelinglz gen'l''r'ltfi'rilth said abutment m inber, 'tdtranSn'iit "a resultant forcebtw'n 'said'r'iieiiibers liav'ing's'ubfs'tantially no lateral 'edmpbfi'nt' tendiiiglo urge said "Gutter means outwardly.

ARCHER;*W. KAMME-RER.

Number Name Da-te 2,466,991 Kammerer Apr. 12-1949

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