US1995389A

US1995389A - Disk bit

Info

Publication number: US1995389A
Application number: US694822A
Authority: US
Inventors: John H Howard; Alfred C Catland
Original assignee: Globe Oil Tools Co
Current assignee: Globe Oil Tools Co
Priority date: 1933-10-23
Filing date: 1933-10-23
Publication date: 1935-03-26
Anticipated expiration: 1952-03-26

Description

. .,s. H, HCWARDYET Al. 1,995,339

DISK BIT Filed 001;. 23,. 1933 J mf rd A/fred Caf/ana f /0 MM orn@ , /8 :Il-4 /m/en crs John /71 Houra lA 0. ,7:54:14 Y l Patented Mar. 26, 1935 UNITED STATES DISK BIT John H. Howard, Huntington Park, and Alfred C. Catland, Alhambra, Globe Oil Tools Company, corporation of California Calif., assignors tol e Los Nietos. Calif., a

Application 'october 23, i933, seriai'No.- 694,822 s claims. (01.255-71) This invention relates to'a well drilling tool and relates more particularly to a disk bit for use in the rotary method of well drilling. It is a general object of this invention to provide a simple, practical and disk bit for well drilling.

A type of well drilling rotary disk bit that has been introduced involves pairs of cutters, each pair of cuttersbeing connected to rotate in unison, and each pair consisting of a leading disk cutter for acting on the formation at'the bottom of the well bore, and atrailing cutter for reaming the bore and forY causingrotation of the leading cutter. We will make reference to Patent No. 1,867,545 granted to S. M. Akeyson, July 19, 1932, as disclosing the general type of bit just referred to; In well bits of this character, it has been the usual practice to form and position the reaming cutters so asto have extensive engagement with the earth formation and take or assume a substantial amount of the weight or feeding pressure applied to the bit so that he leading or principaly cutters do not assume or act under suflicient pressure for their eiiicient operation and penetration of the earth formation. Further, the cutters of bits of the character mentioned above are usually vertical so that they leave a comparatively largevupstanding core and the circulation iiuid is usually discharged from vthe shank or body of the bit at a'point spaced so far above the bottom of the bore that a proper turbulence is not maintained in the bore.

It is an object of the invention to provide a well bit including a pair of disk cutters connected to rotate in unison, the leading cutter of the pair being operatable to eiTectively form or cut the well bore, and theI trailing cutter-of the pair bei`ng operatable to ream the bore and cause the positive rotation of the leading cutter without assuming any appreciable amount of the weight or feeding pressure on the drill so that it does not impair the cutting speed and efciency of the leading cutter.

' It is another object of the invention to provide a well drill having two pairs of disk cutters, the cutters of each pair being connected to rotate in unison and the cutters of the two pairs being pitched or inclined to have their lower ends toe in toward the center of the well bore so as to leave a comparatively small core which may be readily broken up and eroded and washed away by the circulation fluid.

It is another object of the inventionk to provide a well drill or bit having spaced pairs of disk cutters on its lower end and a uid discharging member projecting downwardly between the pairs of cutters to discharge the circulation fluid or rotary mud at a point comparatively close to the bottom of the well bore to properly flush the cutters and to maintain an particularly efficient rotary4 effective turbulence in the bottom of the .well bore. lt is another object of the invention to provide a well bit having spaced pairs of disk cutters at its lower end and an improved and 'particularlyv effective uid discharging ow bean or choke projecting downwardly between the pairs of cutters and detachably or replaceably connected withthe body of thedrill in a simple and dependable manner.

It is another object of the invention to provide a'well bit having two pairs of disk-cutters at its lower end, the cutters of eachy pair being connected for rotation in unison, the leading cutters of the pairs being the principal cutters operating to form or cut the Well bore and the trailing cutters of the pairs being formed and positioned to have only very limited engagement with the earth formation atthe side wall of the bore in a manner to cause the desired rotation of the cutters, to ream the bore and to stabilize the drill without assuming any appreciable amount of the feed pressure on the drill so that practically all of the pressure is concentrated on the leading cutters causing them to be particularly rapid and eflicient in their cutting action.

It is another object of the invention to provide a rotary disk bit of the character mentioned that is simple and inexpensive of kmanufacture and that is smooth running and eicient in operation.

. Itis a further object of the invention to provide a simplified and improved means for rotatably mounting the disk cutters of a well bit.

Other objects and features of the invention will be best and fully understood from the following typical form and application of the invention, through which description reference is Yhad to the accompanying drawing, in which:

Fig. 1 is a front elevation of the bit provided by the present invention with a lower portion broken away to appear in vertical cross section.

Fig. 2 is a transverse detailed sectional view taken as indicatedl by line 2-2 on Fig.` 1, and Fig. 3 is a fragmentary side elevation of the lower portion of the drill with afpart broken away to appear in vertical cross section.

The well drilling bit provided by this invention includes, generally, a body or shank l0, two pairs of disk cutters ll and l2 rotatably mounted on the lower end of the shank l0, and fluid handling means 13 for discharging the circulation uid downwardly between the pairs of cutters.

The body or shank of the bit may be varied considerably in shape, proportions, etc., without departing from the principles of the invention. The particular shank 10 illustrated in the drawing comprises an elongate cylindrical portion 14 provided at its upper end with suitable means for connecting with an operating string or drilling string. In the case illustrated, a tapered screwthreaded pin 15 is provided on the upper end of the shank 10 toconnect with a drill collar or the lower end of a drilling string. The lower portion of the shank 10 is bifurcated, having two spaceddownwardly projecting legs 16. The body of the shank 10 may be enlarged where the legs 16 join the elongate cylindrical portion 14. The

.legs 16 are provided to carrythe pairs of cutters substantially parallel. The outer vertical or longitudinal corners of the legs 1,6 are preferably bevelled or rounded in the manner illustrated throughout the drawing. .Each leg 16 carries a pair of cutters, there being a rotatable cutter 11 at the' inner side of each leg and a trailing or teaming cutter l2 at the outerside of each leg.

The' cutters 11 and 12 are in the nature of disk cutters, the cutters 11 being the principal cutting or formation penetrating cutters, and the cutters 12 being the reaming, stabilizing and driving cutters causing the desired rotation of the principal cutters l1. The cutters 11 are comparatively large in diameter and preferably have plain circular peripheries. The inner sides 20 of the cutters and the rear sides 2l of the cutters 11 may be bevelled at their peripheries to join the inner sides 20 at peripheral cutting edges 22. Central openings 23 are provided in the cutters 11 and projecting bosses 24 are provided on the sides 20 around the openings 23.

'I'he reaming cutters 12 are considerably smaller in diameter than the cutters 11 for the purpose to be subsequently described. The reaming cutters 12 may have at substantially parallel opposite sides. The peripheries of the reaming cutters 12 arepitched or bevelled, and are provided with teeth 25. The teeth 25 are circumferentially spaced and are helicoidal or spiralled. In accordance with the invention, the teeth 25 of the cutters 12 are pitched or spiralled in a direction to have effective reaming engagement with the wall of the well bore and to cause positive rotation of the cutters. The cutting or formation engaging edges 26 of the teeth 25' may -be continuous or unbroken. Each cutter 12 is provided with a central longitudinal opening 27.

The yinvention provides improved and simplined means for rotatably mounting the pairs of cutters 11 and 12. In accordance with the inventionfthe pairsof cutters 11 and 12 are rotatable about axes inclined downwardly and out.

wardly relative to the axis of rotation of the bit which axes areinclined downwardly and outwardly in opposite directions relative to one another so that the lower parts of the pairs of cutters toe in or converge toward the center of the well bore. The axes of rotation of the pairs of cutters are substantially normal to the

sides

17 and 18 of the legs 16. The mounting means for each pair of cutters includes a journal or pin 30 carrying the cutters and rotatably supported by a leg 16. A transverse opening 31 is provided in each leg 16 to pass or carry a pin 30. The openings 31 have longitudinal axes substantially normal to the inner and outer sides of the legs. In accordance with the invention, the openings 31 of the two legs 16 are outof longitudinal alignment, the opening 31 in each leg being closer to the leading edge or side of the leg relative to the direction of rotation of the drill than .it is to trailing edge or side of the leg. This positioning of the openings 31 provides for the projection of the cutters 11 from the forward or leading sides of the legs 16 as illustrated throughout the draw- Replaceable bushings 32 are provided in the openings 31 to rotatably carry the pins 30. -Flanges 33 are provided on the outer ends of the bushings 32 to seat in recesses 34 in the outer sides 18 of the legs. Nuts 35 are threaded on the inner end portions of the bushings 32 to engage the inner sides 17 of the legs and retain the bushings in position. Dowel pins or keys 36 cooperate with longitudinal notches in the exteriors of the bushings 32, to prevent rotation of the bushings and nuts. The cutter carrying pins 30 are rotatable in the bushings 32 and project from the opposite sides of the legs 16 to carry the cutters 11 and l2. 'Ihe projecting portions of the pins 30 are reduced in diameter to rit the openings in the `cutters and to provide thrust shoulders 37. The

reaming cutters 12 are provided on the outer projecting portions of the pins 30 and are rigidly or iixedly attached to the' pins. In the particular case illustrated in the drawing, the reaming cutters 12 are welded to the pins 30 and have their inner sides bearing "against the thrust shoulders 37. The inner sides of the reaming cutters 12 may also have bearing engagement with the bushings 32 and their ilanges 33.

The cutters 11 are threaded on the projecting irmer end parts of the pins 30, their openings 23 having threads cooperating with threads on the reduced inner end parts of the pins. The cutters 11 are preferably threaded on the-pins 30 to have their inner sides bearing against the thrust shoulders 37. The provision of the nuts 35 provides for the proper or suitable spacing of the cutters 11 from the inner sides 17 of the legs 16. The bosses ofthe cutters 11 are provided with a plurality of pairs of diametrically opposite notches 38, andlock pins 39 areadapted to be passed through transverse openings 40 in the pins 30 to cooperate with notches 38 to lock the cutters 11 against rotation on the pins 30. The projection parts of the lock pins 39 may be bent over to prevent the displacement of the pins. Wrench slots 41 are provided in the outer ends of the pins 30 for the reception of wrenches or other turning and holding tools. A transverse opening 43 is provided in each cutter 11 to pass a rod or tool for engaging a leg 16 to hold the cutter against rotation when the pin 30 is being threaded into or out of the cutter opening 33. i

With the cutter mounting means just described, the cutters 11' and 12 on each leg 16 are adapted for rotation in unison. 'I'he cutters 11, which are at the inner sides 17 of the legs 16, project from the forward'or leading sides of the legs relative to the direction of rotation of the drill to have effective cutting engagement with the wall of the well bore. The reaming cutters 12 which are disposed at the outer sides 18 of the legs 16 are considerably smaller in diameter than the cutters 11 so that they do not have active engagement with the `formation at the bottom of the well and only engage the formation throughout limited parts of their peripheries at what may be termed the side wall of the well bore. The pairs of cutters 11 and 12 are rotatable about axes inclined-downwardly and outwardly so that their lower end portions toe inwardly toward the center of the well bore whereby the principal cutters 11 leave only a very small upstanding portion of formation or core 50. The means for rotatably mounting the pairs of cutters are such that the cutters may be easily and quickly assembled on the bit and may be readily replaced when found desirable.

The means 13 for handling the rotary mud or circulation fluid operates to discharge the circulation fluid downwardly between the cutters 11- at a point suiiiciently close to the bottom of the well bore to maintain an effective turbulence at the bottom of the bore and to insure the complete g flushing of the cutters. 'I'he means 13 includes a central longitudinal fluid passage 60 extending through the shank 10 from the upper end of the pin 15 to a fluid conducting member 61 projecting downwardly between the cutters 11. The member 61 may be an integral part of the shank 10 as initially formed; however, the construction or manufacture may be simplified by forming the member 61 separate from the shank and then attaching or connecting it with the shank in a suitable manner. In the particular construction illustrated in the drawing, the upper end portion of the member 61 is received in a socket 62 at the lower end of the passage 16 and is welded to the shank. .The uid passage 63 of the member 61 is of elongate transverse cross section and is elongated in a direction substantially transverse of the axes of rotation of the cutters 11 and 12. The iiuid passage 63 may be of downwardly diminishing area or capacity.

A replaceable choke or bean 63 is provided on the lower end of the member 61. The bean 65 is substantially rectangular in horizontal cross sectional conflguration, having a fluid discharge opening 66 of the same shape. The upper end portion of the bean 65 lits a correspondingly shaped socket 67 in the lower end of the member 6l. 'I'he discharge opening 66 of the bean 65 is of less area or uid capacity than the lower end of the passage 63 and is transversely elongated in the same direction as the passage 63. In being of smaller dimensions and fluid capacity than the passage 63, the discharge opening 66 of the pin 65 causes the circulation uid to be discharged downwardly between the cutters 11 at an increased velocity. 'I'he restricting bean 65 may be subjected to considerable erosive action by the solid matter in the circulation uid, and the invention provides a simple and effective means for dependably replaceably attaching the bean to the member 61. Wedges 70 are passed or driven through transverse openings 71 in the member 61 and cooperate with notches 72 in the opposite ends of the bean 65 to tightly clamp or hold the bean in position. The wedges 70 are such that they dependably hold the bean in place but may be readily driven from their openings 71 when it is desired to replace the bean. Packing 75 is arranged between the upper end of the bean 65 and the upper end of the socket 67 to seal between the bean and the member 61. The action of the wedges 70 maintains the packing 75 in a compressed sealing condition. The bean 65 discharging the circulation fluid downwardly between the cutters 11 has its lower end in approximately the same plane as the inner ends of the pins30 so as to discharge the fluid downwardly at a point only a short distance from the bottom of the well bore bringing about the complete flushing of the cutters and the vmaintenance of an effective turbulence in the lower end of the well bore.

It is believed that vthe operation of the well bit provided bythis invention will be readily ap-I parent from the foregoing detailed description. In operation, the bit is rotated in the usual manner and is maintained under a desired or suitable drilling or feeding pressure. It is the usualpractice to rotatev the bit in the right hand or clockwise direction. As the drill is rotated, the cutters 11 engage the formation to make an annular cut indicated in a more or less diagrammatic manner in Fig. 1 as out or line A-A. yIt is to'be noted that the cutters 11, in havingtheir lower portions inclined inwardly and downwardly toward one another, leave only a verysmall co're 50 which is readily broken up and which yis washed away by the downwardly dischargingirculation fluid. The reaming cutters or trailing cutters 12 do not have contact with the formation at the bottom or upwardly facing wall of the wellI bore but engage the. formation at a circumferential plane or area only slightly below the'centers of the outer ends of the pins 30. The cutting zone or\area of the reaming cutters 12 is indicated approximately by the character C in Fig. 1 of the drawing. In considering a single reaming cutter 12, it will be noted that it is disposed and mounted so that the engagement of its teeth,25

with the formation at the zone described above causes it to rotate in the `direction indicated by the arrow in Fig. 3 of the drawing. The path taken by the peripheral edge of the cutter 12 is indicated by the broken line B-B in Fig. 1 of the drawing, it being noted that the cutter 12 does not contact with the bottom or the upwardly facing portion of the wall of the well bore. The rotation of the roaming cutter 12, of course, causes corresponding rotation of the cutter 11 with which it is connected. During any A phase of operation of a reaming cutter 12v it has only a comparatively limited series of cutting teeth 25 in engagement' with the earth formation, for example, it may have the series of teeth A, B and C contacting with the formation. Further, the extent of engagement of the cutting edges26 of 'theteeth'A, B and C is limited, for example, the tooth-A has a part X-Y of its edge 26 contacting with the wall of the well bore, the tooth B has the portion M-N of its cutting edge engaging the wall of the bore, and the tooth C has the portion S-'T of its cutting edge engaging the bore. It is to f be noted that the series of teeth A, B and C engage or act on the formation at the forward or leading edge of the, cutter'12 at points at or slightly below the plane of axis of rotation of the cutter.

'I'he cutter 12, in acting on or engaging the earth formation as just described, assumes very little of the drilling pressure or feed pressure on the bit, but its engagement with the formation is such as to cause positive rotation of its associated cutter 11, the effective reaming of the Well bore, and the stabilization of the bit. 'I'he reaming cutters 12, in taking or assuming only a slight bore to maintain the desired turbulence at the cutting parts. In practice, the bean 65 may discharge the circulation fluid downwardly at a point adjacent the inner ends of the pins 30. The bean 65 materially restricts the lower end of the fluid passage to increase the velocity of the discharging fluid. Due to this functioning, the bean 65 is subjected to considerable erosion by the solid matter in the fluid. The wedges '70 attach the bean 65 to the member 61 so that it may be easily and quickly detached for replacement.

The means mounting the cutters l1 and l2 are dependable and effective and are simple and inexpensive of manufacture. In assembling a pair of cutters ll and 12 on a leg 16, the bushing 32 is rst arranged in the opening 3&1 and is secured in place by means of the nut 35 and the key 36. The pin 30 carrying the attached reaming cutter 12 is then passed through the bushing 32 and the cutter l2 is threaded on to its projecting inner end part. A rod or suitable tool may be passed through the opening 23 of the cutter l1 to engage a leg 16 or other part to hold the cutter against turning, while the pin 30 is threaded through the cutter by a wrench or the like cooperating with the slot 4l in the outer end of the pin. When the cutter 11 has been threaded to the proper position on the pin 30, the cotter or pin 39 is passed through the opening 40 and its opposite end portions are made to cooperate with notches y38 to lock the cutter against displacement from the bean. The mounting means is such that the cutters 11 and 12 may be easily and quickly replaced when worn.

Having described only typical forms and applications of the invention, we do not wish to be limited or restricted to the specic forms or applications herein set forth, but wish to reserve to ourselves any modiiications or variations that may appear to those skilled in the art or fall within the scope of the following claims:

'Having described our invention, we claim:

1. A `well bit including, a shank, a leg projecting from the lower end of the shank, a disk cutter at the inner side of the leg, a reaming cutter at the outer side of the leg, and means connecting the cutters for rotation in unison about an axis inclined downwardly and outwardly relative to the axis of rotation of the shank.

2. A well bit including, a shank, a pair of spaced legs projecting from the lower end of the shank, a disk cutter at the inner side of each leg, a reaming cutter at the outer side of each leg, and means on each leg mounting the adjacent disk cutter and the adjacent reaming cutter for rotation in unison about an axis inclined downwardly and outwardly relative to the axis of rotation of the shank.

3. A well bit including, a shank, a pair of spaced legs projecting from the lower end of the shank, a disk cutter at the inner side of each leg, a reaming cutter at the outer side of each leg, the reaming cutters being of smaller diameter than the said disk cutters, and means on each leg f mounting the adjacent disk cutter and the adjacent reaming cutter for rotation in unison about an axis inclined downwardly and outwardly relative to the axis of rotation of the shank.

4. A well bit including, a shank, a pair of spaced legs projecting downwardly from the lower end of the shank, a pin carried by each leg to project from 4its inner and outer sides and rotatable about an axis inclined downwardly and outwardly relative to the axis of rotation of the shank, a cutter attached to the inner projecting part of each pin to rotate therewith and operatable to cut a comparatively wide path in the earth formation, and a cutter attached to the outer projecting part of each pin to rotate therewith and operatable to engage the formation to ream the bore and cause rotation of the pin and thc cutter on the inner part of the pin, the last mentioned cutters being proportioned and mounted to assume only a slight amount of the feed pressure on the drill.

5. A well bit including, a shank, a pair of spaced legs projecting downwardly from thelower end of the shank, a pin carried by each leg to project from its inner and outer sides and rotatable about an axis inclined downwardly and outwardly relative to the axis of rotation of the shank, a cutter attached to the inner projecting part of each pin to rotate with the pin and operatable to cut a comparatively wide path in the earth formation, and a cutter fixed to the outer projecting part of each pin and Operatable to engage the formation to ream the bore and cause rotation of the pin, the last mentioned cutters including spiralled peripheral cutting teeth.

6. A well bit including, a shank, a leg projecting downwardly from the shank, the leg having I.'

a transverse opening, a removable pin passing through the opening to project from the opposite sides of the leg and to rotate about an axis inclined downwardly and outwardly relative to the axis of rotation of the shank, a reaming disk cutter xed on the projecting outer part of the pin, a disk cutter threaded on the projecting inner end part of the pin to rotate with the pin and removable means locking the last mentioned disk cutter against unthreading.

7. A well bit including, a shank, a leg projecting downwardly from the shank, the leg having a transverse opening, a removable pin passing through the opening to project from the opposite sides of the leg and to rotate about an axis inclined downwardly and outwardly relative to the axis of rotation of the shank, a reaming disk cutter xed on the projecting outer part of the pin, a disk cutter threaded on the projecting inner part of the pin, a notched boss on the said :c

disk cutter, and a removable part arranged through an opening in the pin and cooperating with a notch of the boss to lock said disk cutter.

8. A well bit including, a shank, a leg projecting downwardly from the shank, a leg having a transverse opening, a removable pin passing through the opening to project from the opposite sides of the leg and to rotate about an axis inclined downwardly and outwardly relative to the axis of rotation of the shank, a removable bushing in the opening carrying the pin, a holding nut threaded on the bushing, a key holding the bushing and nut against relative turning, a reaming disk cutter xed on the projecting outer part of the pin, a disk cutter threaded on the-projecting inner part of the pin, and removable means locking the said disk cutter against turning on the pin.

JOHN H. HOWARD. ALFRED C. CATLAND.