US2121112A - Means for circulating fluid around drill bits - Google Patents

Description

- J. A. ZUBLIN MEANS FOR CIRCULATING FLUID- AROUND DRILL BITS 3 Sheets-Sheet 1 v Filed Aug. 28, 1957 Z 14 j 1,? 27 13 26 2 1o 15 Stratum June 21, 1938, J. A. ZUBLIN MEANS FOR CIRCULATING FLUID- AROUND DRILL BITS Filed Aug. 28, 1937 3 Sheets-Sheet 2.

awe/rm Hum 1 Juqe 21, 1938.

1 A. ZUBLIN MEANS FOR CIRCULATJEENGVFLUID AROUND DRILL BITS Filed Aug. 28, 19.37 3 Sheets-Sheet 3 .w 4 4 W m m a. a w J W m w a z w Hm a A s 4 J Patented June 21, 1938 2,121,112 FOR CIRCULATING FLUID AROUND DRILL- BITS John A. Zublin, Los Angeles, Calif.

Application August 28, 1937, Serial No.*161,484=

10 Claims. (01. 255-71) The present invention relates to fluid circulating systems. for drill bits, and particularly to that class of bits that performs its functions through the rotation of a drilling string attached to it.

This application is a continuation in part of my application No. 133,860 flied March 30, 1937.

A considerable drawback to efllclent operation of culating systems resides in their inability to remove the cuttings from the bottom of the hole.

A fluid nozzle is usually inserted in the center of the shank above the cutting teeth, directing its stream downwardly toward the bottom. It is intended that this stream clear the bit of all adhering matter and also remove the cuttings. But this intention is rarely realized since the downward'stream actually interferes with upward car- Y riage of the cut particles to the surface of the bore, because the flow channels are not maintained separate and distinct. A mass of cuttings accumulates on the bottom and serves as a cushion against formation penetration by the cutting edges of the'bit. This factor coupled with adhesion of cuttings to the teeth requires excessive drilling weights in an effort to contact with the bottom of the hole, letting alone any possibility of actually penetrating the formation. Invariably, this excess weight results in the drilling of a crooked hole.

bottom of a drilled hole.

It is a further object of this invention to remove from caking on the teeth andeventually balling up the bit.

It is a further object of my invention to provide Accordingly, it becomes an object of this invention to remove cuttings effectively from they a fluid circulating system of a character to insure use .of a clean tool throughout its drilling life.

It is a further object of my invention to decrease the resistance to rotation of a bit by its surrounding fluid.

How these objects and others are accomplished is' ascertainable from a consideration of the following speciflcation and attached drawings, in which: f

Fig. 1 is a longitudinal sectional view of a drill bit takenalong the line l-l of Fig. 2

Fig. 2 is a longitudinal sectional view of a drill bit taken along the line 2-2 of Fig. 1;

Fig. 3 is a side view along the line 3-3 of Fig 2;

Fig. 4 is a diagranmiatic representation of the flow of fluid around the bit and hole;

Fig. 5 is a modification of my invention and is- ,in part a longitudinal section of the drill bit taken along line 5-5 of Fig. 6.

Fig. 6 is a side view of my invention taken along line 6-6 of Fig. 5.

Fig. 7 is a partially longitudinal sectional view of another modification of my invention; and

Fig. 8 is a bottom view taken along the line 8-8 of Fig. 7.

Like reference numbers refer to the same parts throughout the several views.

In Figures 1 and 2,-is illustrated a drill bit provided with a shank Ill, having on its upper end a. threaded portion l I, by means of which the shank is attached to a drilling string for rotation about a generally longitudinal axis A-A. As described in my application No. 111,871, filed November 20, 1936, now Patent No. 2,079,142, granted Mar. 4, 1937, the lower portion of the shank is provided with two depending legs I2 carrying between them a cutter carrier l3. About the periphery of the cutter carrier is rotatably mounted a plurality of roller cutters l4. 1

As described in my prior application, the carrier is rotatably mounted between the shank legs by means of bearing member l5, which consists of a central cylindrical sleeve l6 and flanges I! screwed into each end'of the bearing sleeve. The carrier has an inner cylindrical surface l8 rotatably mounted on the sleeve, and inclined surfaces l9 complementary to the flanges. Between the flanges and these inclined surfaces are ball bearings 20 which serve to transmit part of the radial load on the carrier and all of the axially parallel loads. On the outer surface of each flange is provided a raised boss 2| which is inserted into a. transverse slot 22 in each of thelegs of the shank. The bosses are flattened across their top and bottom sides 23, 24 in order that they can be slid into the'slots in the legs and be held from rotating relatively thereto. Relative rotation between the flanges is prevented by means of a locking pin 25.

- The entire bearing assembly is attached to the legs of the shank and held in proper position by tapered pins 26 which are externally threaded at 21, cooperating threads being supplied in each flange. Removal of the tapered pins is prevented by inserting cotter keys 28 through a bore 29 in each pin, the legs of each key being bent back to engage with castellations 3|) in each pin an with grooves 3| in the shank.

To lubricate the bearing surfaces, passageways 32 for the circulating fluid are supplied at intervals around the carrier. These passageways will convey the fluid from each roller cutter to the bearing surfaces. v

The upper end of the shank is provided with an internal fluid passage 33, at the lower end of which is threaded a discharge orifice or nozzle 34. To eliminate the possibility of the stream issuing from the nozzl from impeding rotation of the carrier about its own axis, the nozzle is inclined to the vertical by angle a so as to eflect a discharge in the direction of carrier rotation. The fluid will be directed against the sides 35 of the carrier defining the slots 36 in which the roller cutters are mounted, and exert a force causing carrier rotation, in much the same manner as a stream issuing from a fluid nozzle will rotate a water wheel by impinging on its buckets, or a turbine disc by impact and reaction on its blades.

Inclining the nozzle has an additional effect of impinging the circulatingfluid against the teeth of each roller cutter with a combined tangential and longitudinal direction. While the fluid will cause the rotation of each cutter, its spinning action will not be as great as when the discharge is entirely tangentially of the cutter with its total force being spent in turning eflort. Despite this decreased rollerrotation, the cleansing action will be materially increased due to the fact that the longitudinally moving stream engages all parts of each tooth face with substantially undiminished velocity.

By referring to Fig. 2, it will be noticed that "the nozzle is offset somewhat with respect to a plane including the shank axis. This design provides an unobstructed path of part of the fluid stream to the sides of the carrier slots, while the remainder of the flow engages the cutter teeth. Part of this latter flow will be deflected from the teeth and also will strike against the sides of the slots.

' It will be noted further that as wear occurs on the cutting teeth a greater area on the carrier is exposed to the direct action of the fluid stream issuing from the discharge orifice. Con- 60 'sequently, a greater force is being exerted by the nozzle to cause carrier rotation. This compensates to a great extent for the decreased rotation of the carrier due to a lessened penetration in the formation by the teeth as they wear. Ordinarily, as bluntness of the teeth increases, a greater amount of slipping will, occur, and the carrier will not rotate to the same extent as previously. By the above described design, the decreased action of rotation of the carrier caused by formation contact of the cutting teeth is offset by the increased turning eifect produced by the discharge orifice.

The cuttings are removed from the bottom of i the hole by fluid issuing from a nozzle 31 screwed shank. A streamlined watercourse 38 establishes communication between that nozzle and the internal fluid passage in the upper end of the shank. To clear the tapered pin bearing support, the watercourse is curved around it to meet the nozzle at a position displaced with respect to the carrier axis BB. The nozzle is inclined somew t to the shank axis, and this inclination coupled withits displacement as regards the carrier axis, and with the inclined upper nozzle 34 produces highly desirable effects, as will now appear from a consideration of Fig. 4.

The lower nozzle 31 projects a stream downwardly towards the bottom of the hole. Since drill bits of the type disclosed form a. hemispherical surface, the stream will be deflected circumferentially by that surface in a curved path n, n along the cup shaped bottom, clearing the hole of all cuttings and carrying them with the fluid upward in the direction m, m. The inclination of the nozzle aids in this direction of flow by initially reducing the slant between it and the curved hollow bottom surface of the bore. As the shank rotates, the lower nozzle will revolve with it and direct its stream of water along paths generally of the nature designated by the arrows n, n, m, m, to all parts of the hemispherical surface and the cylindrical bore above it, insuring their thorough flushing of all particles from the vicinity of cutting of the bit. It will be noted that the placement of the nozzle near the bottom of the hole practically elim inates interference between the clean. stream of fluid leaving the nozzle and the mixture of fluid and cuttings moving in an upward path toward the top of the bore. This lack of interference keeps the hemispherical region of cuttings free of foreign-matter at all times and permits effective penetration of the cutting teeth into the formation with a minimum of drilling weight.

In prior fluid circulating systems, the column of liquid is static as regards circumferential movement around the bore. This necessitates an expenditure of power merely to move the column ahead of a rotating bit. The transmission of this additional power through the drill pipe adds to its straining and twisting, and thereby prevents smooth running of the bit in the hole. If the liquid column could be caused to move around the bore in the direction of rotation of the drill pipe by some other means than the bit, the rotational resistance of the fluid would be decreased, with attendant smoother operation. The positioning of the lower nozzle produces this latter eflect. i

The lower nozzle is offset by a distance x fro the central plane of the bore including the shankand carrier axis. Because of the offset the stream leaving the nozzle, besides causing flow in longitudinal planes in the direction 11., n, n1 n1, will also urge the liquid column in the circumferential direction indicated by the arrows m, m, which is the direction of motion 1' of the drill pipe and bit. This circumferential motion of the fluid will be assisted somewhat by the slight offsetting of the upper nozzle by the distance'y. A leverage will be added to the force of fluid issuing from that nozzle to move it in the direction of the arrows q, q,- which is also the direction of rotation of the drill pipe and ,bit. By t e use of these expedients, the relative speeds of the bit and liquid column are decreased so that the displacement of fluid by the bit is lessened, as is its resistance to rotation.

Because of the illustrated arrangements of the upper nozzle, the tendency of the fluid stream to retard motion of the carrier is not only eliminated,'but the stream is so directed as to insure and tend to increase rotation of the carrier. As a result, all of the advantages of drill bits of this type are maintained throughout the entire life of the cutter teeth. Primarily, these include intermittent contact of the formation by the roller cutters, a consequent reserve of cutters at all times, and thorough cleansing of all of the parts. 1

The lower nozzle will keep the bottom of the hole free from cuttings at all times, and due to its ofiset position will decrease the resistance to rotation of the bit offered by the fluid column. In this latter effect, it will be assisted by the upper nozzle.

Although the improved nozzle arrangements have been described in connection with an inclined carrier, it is to be understood that the same principles of operation, and general constructional features are applicable to other embodiments of roller carrier bits; to other types of cutter carriers, such as in roller cones and disc bits; and in certain respects to any type of cutting tool.

There is a furtheradvantage associated with the placement of the nozzle 31 so that it directs its stream of fluid against the formation near the bottom of the hole. Besides removing the cuttings'from the bottom of the hole, the stream will be deflected by the formation so as to also impinge against the rollers in contact with the formation I to prevent adherence of cuttings to the t'eeth'gbut if any does adhere, to remove such cuttings immediately thereafter. In the latter instance, this cleansing action occurs practically with the dis- I harden.

A similar arrangement is disclosed in Figs. 5 and 6, but with the lower nozzle being replaced by two nozzles which are incorporated in the other leg of the shank. Each nozzle 39 is threaded into the short leg of the shank I and communicates with a water course 38a, the other end of which opens into the internal fluid passage 33. The placing of the nozzles in the other leg possesses the advantage of a straight watercourse as distinguished from the curved conduit 38 illustrated in Fig. 2 This eliminates the tendency of the drilling mud to out through the sides of the water course by reason of the necessity for going around bends.

The fluid issuing from the two water courses 38a will follow the same general lines indicated by the dotted arrows 'n-n illustrated in Fig. 4. That is, they will impinge against the formation and be guided by its concave or hemispherical surface to direct streams of fluid transversely across the bore, and in doing so remove cuttings from the bottom of the hole. Substantially simultaneously the fluid streams will also engage against the rolling cutters in contact with the formation and cleanse them of adhering matter while in contact or as soon as the teeth emerge fromcontact with the formation.

The other details of construction of the arrangement shown in Figs. and 6 are the same the hole is flat. The shank 40 of the drill bit has at its upper end a threaded pin 40a which is adapted for attachment to a drill collar. The lower end of the shank supports the side cutting rollers 4| and the cross cutting rollers 42. The first mentioned cutters are disclosed as being diametrically opposite to one another and are each rotatably mounted on bearing pins 43, one

end of which is flxed to the bridge 44 and the other end of which is welded to the shank at 45. The cross cutting rollers are likewise rotatably mounted upon pins 46 which aresupported at one end in the bridge 44 and at the other end are welded to the shank legs at 41. It will be noted that the side cutting rollers, as their name indicates, will remove formation at the outer margins of the bore; while the cross-cutting rollers 42 will remove the formation at the inner surface of the bottom of the hole; the two sets of rollers combining to remove all of the formation essential to the maintenance of the bore diameter.

The upper part of the shank has a fluid passageway 48 with two'ducts 49 permitting drilling mud to issue therefrom and impinge on the side cutting rollers to cleanse them of adhering matter. Additionally, there are provided two other flui. conduits 50 passing through the bridge 44 and joining together to form the single duct 5! before communicating with the passageway 48. These latter conduits 50. have openings at the bottom of the bridge 5| and are inclined to the vertical in opposite direc-' tions so as to direct streams of fluid at an inclined angle to the bottom of the hole. This arrangement is provided in order to remove the cuttings from the bottom of the hole and cause them to flow upwardly with the drilling fluid as shown by the arrows 17. At the same time the fluid will be deflected from the bottom and pass between the cutting teeth on each roller to cleansethem of any earth that might tend to adhere thereto. In this manner, which is similar to the action disclosed in connection with the drilling bits shown in- Figs. 1 to 7, inclusive, the fluid stream is guided by the formation along the bottom of the bore and transversely thereof to keep the bottom free from cuttings, and it is also deflected from the bottom to impinge against the cutting teeth in order to prevent caking of the cuttings thereon so that adequate penetration into the, formation can be had at all times.

While I have described a specific application of my invention, it is to be understood that changes may be made in its construction and the arrangement of its parts without departing from the intent and scope of my invention, and that the foregoing description is to be considered illustrative of, rather than restrictive upon the following claims.

The invention associated with the use of the inclined nozzle 34 alone is claimed in my copending application No. 133,859 filed March 30, 1937 for Improvements in drill bits.

' I claim as my invention: 1. An earth boring tool comprising a shank carried by said legs, cutter mechanism rotatably supported by said means, and fluid discharge means on at least one of said legs in the region of its lower end, said discharge means being offset with respect to the axis of said bearing means.

2. An earth boring tool comprising a shank provided with depending legs, bearing means carprovided with depending legs, bearing means ried by said legs, cutter mechanism rotatably supported by said means, fluid discharge means on at least one of said legs in the region of its lower end, said discharge means being offset with respect to the axis of said bearing means,.

an internal passage in said shank, and flow means connecting said passage and discharge means.

3. An earth boring tool as in claim 1, including a second fluid discharge means on said shank mounted outwardly of the cutter mechanism, said second discharge means being oflset with respect to the shank axis.

4. An earth boring tool as in claim 2, including a second fluid discharge means on said shank mounted outwardly of the cutter mechanism, said second discharge means being offset with respect to the shank axis and having communication with said passage.

5. An earth' boring tool comprising a shank provided with depending legs, a carrier supported by and between said legs for rotation about a transverse axis, roller cutters circumferentially mounted on said carrier, a fluid passage in the upper part of said shank, a fluid discharge means opening at the lower end of one of said legs, said means being oflset from'a longitudinal plane including the carrier axis and being below said axis,

and a duct connecting said passage and fluid.

means.

6. An earth boring tool comprising a shank provided with depending legs, a carrier supported by and between said legs for rotation about a transverse axis, roller cutters ci'ircumferentially mounted on said carrier, a fluid passage in the upper part of said shank, a fluid discharge means opening at the lower end of one of said legs, said means being ofl'set from a longitudinal plane including the carrier axis and being below said axis, a duct connecting said passage and fluid means, and a second fluid discharge means on said shank mounted outwardly of the cutter mechanism, said second means being offset with respect to the shank axisand having communication with said passage.

7. An earth boring tool operable to produce a hemispherical bottom in a. well bore being drilled comprising a shank, a cutter carrier rotatably mounted on the shank, a plurality of cutters rotatably mounted on the cutter carrier, and fluid means on said shank arranged at an angle to the tool axis and positioned to discharge a full jet of fluid against the bottom of the bore at an angle which will cause said bottom to guide the fluid transversely across the bore for jet cleansing action upon the cutters substantially where they contact with the bottom.

8. An earth boring tool operable to produce a hemispherical bottomin a well bore being drilled comprising a shank, a cutter carrier rotatably mounted on the shank for motion about an axis, a plurality of cutters rotatably mounted on the cutter carrier, and fluid means on said shank arranged at an angle to the tool axis and positionedto discharge a full jet of fluid against the bottom of the bore at an angle which will cause said bottom to guide the fluid generally longitudinally of the axis of rotation of the carrier and transversely across the bore for jet cleansing action upon the cutterssubstantially where they contact with the bottom.

9. An earth boring tool comprising a shank, a cutter carrier rotatably mounted on the shank, a plurality of cutters rotatably mounted on the carrier operative to produce a hemispherical bottom on the formation being bored, and fluid means on said shankoutside said cutters and arranged at an angle to'the bit axis and positioned to discharge a full jet of fluid against the bot-- tom of the formation at an angle whereby the fluid is guided transversely from one side of the hole axis to the other to contact and cleanse the cutters at their formation contacting surfaces.

JOHN A. ZUBLIN.

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