US2815936A - Drill bits - Google Patents

Description

United States Patent O DRILL BITS;

Robert G. Peter and" Elmer Volmert, Houston, Tem, assgnors to Reed Roller Bit Company, Houston', Tex., a` corporation of Texas Application December 24, 1951, Serial No: 263,054 'Clain'1's'. (Cl. 2551-313) This invention relates"y to ne'vv'andruseful improvements in drill bits.

The invention relates particularly to a= slush nozzle arrangement for drill bits whereby the drilling fluid is directed in a manner to increase the drilling ei'cien'cy of the bit.`

In recent drilling7 practices it" hasbeen found that the use of high velocity'mud streams for Washing and-eroding the bottom of the hole provides a particular advantage in the drillingv operation since thel high velocity jet impinging upon the' bottom of the hole assists in removing the formation. Therefore, the'r trend has been toward the use of higher mud pressuresin order to obtain the high velocity jet" streams which discharge onto th'ebottornl of the hole. have increased drilling-` efliciency it is obvious that such high velocity streams cannot be directed' to impinge upon the drilling cuttersl because such impingement would result in excessive wear of the cutters and-the cutter teeth. By directing the high velocity streamsV onto the bottom of the holel and awayl from the cutters, cleaning of the cutter teethy has' been' sacrificed with a resultant lossy in the cutter eliciency. Thus, although overall drilling efciency hasy been gained? by the use of the high' velocity mud streams, some loss in reduced cutter efficiency has been sustained.

It is one object of the present invention to retain all of the advantages of the" use of high velocity mud streams impinging upon the bottom'of the hole and at the same time to provide a lower velocity stream for impi-ngement against the cutters to maintain said cutters and their teeth clean to permit them to function at full efficiency.

An importan object is to'provideY ay dual nozzle arrangement wherein from a single fluid source a high volume high velocity stream may bei directed upon the' bottom of the hole andl a relatively low volume and low velocity stream may be simultaneously discharged upon the cutters and cutter teeth, whereby maximum drilling efficiency is obtained.

Another object is to provide a dual nozzle arrangement for drill bits wherein the circulating uid or mud is conducted to a nozzle having means for dissipatng the energy of the circulating uid whereby a low velocity stream of lesser volume may be directed onto the cutter teeth to assure cleaning thereof without excessive cutting out or wear because of the abrasive action of the stream.

Other objects will hereinafter appear.

Figure 1 is a transverse vertical sectional View of a drill bit constructed in accordance with the invention,

Figure 2 is a bottom view of the bit,

Figure 3 is an enlarged sectional view schematically showing the dual nozzle arrangement,

Figure 4 is a schematic View similar to Figure ishow ing a slightly modied form of the invention, and

Figure 5 is a sectional View of still another modification of the low velocity nozzle.

ln the drawings the numeral designates the body of Although these high velocityV streams a drill bit havinglthe usual externally threaded pin 11' at its lupper end.` The pin isxprovided with a bore which forms a chamber 12 Within the upper portion of the bit, which chamber is incommunication with the drill pipe (not shown) to which the. bitl is attached. The body ofthe bit is formed with, the usual depending legs 13V and cutters 14 areV mounted onsupportingv spindles 15 which extend inwardly from thezlegs i3. The particular constructionof' the bit, the cutters andthe mounting` ofV said cutters is subject to variation.

It is desirable-that highvelocity iluid streams. or jetsl bedirected downwardly. ontothebottomof the hole dur-- ing the drilling operationy to wash away and erode the formation, and it is. alsodesirable that low velocityl streams be directed ontogthe cutters 14 to maintain the cutting teeth in a clean condition. It might benoted. that the highvelocity streams are preferably. of a high volume while the low velocity streams need only be of a lesservolume;

For directing a high Volume high velocity stream or jet of drilling iluid or mud onto'the bottom of the hole a tubular nozzle levis mounted in they bit body and has its'upper endineommunication with the chamber l2 in the upper portionI of the bit,` whereby drilling-fluid may. be directed downwardly through the nozzle. The lower end of the nozzle is located. to discharge the stream ilow.- ing` therethrough onto the bottom of the hole at a pointk between the cutters 14. As illustrated in Figure, 2, two` of the nozzles 16 are` provided but obviously the number employed may vary. Each nozzle has its bore gradually tapered as indicated at 1/ in Figure 3 with the discharge` end 18- of said bore being' of a diameter in accordance with` the particular velocity which is desired. lt is evident that control of the volumev ofiiuid as well, as. the velocity which is discharged through each nozzle 1t?k is obtained through the diameter of the bore ot the nozzle, together with the diameter of the discharge end 1S thereof. Asy noted,y each nozzle discharges its liuid. stream upon the bottom of the hole at a point between the cuttersso that therhigh volume high. velocity' streams do not impinge upon the cutters i4 or the cutter teeth.

For directing a stream et huid or" lesser volume and. lesser velocity upon the cutters for the purpose of cleaning said cutters, an additional nozzle 19 is provided for each cutter. Each nozzle 19 comprises a conduit or tube 20 having abore 2l of predetermined diameter. The outlet end of each tube is counterbored at, 22 to provide a discharge opening of predetermined size. Within the upper end of the tubeV 29 is mounted an orice plate or collar 23 having an opening 24 of predetermined size therein. Thel plate or collar may be constructed of hard metal to prevent excessive cuttingr out or wear thereof.

As the pressure fluid or mud which is circulated downwardly through the drill pipe and chamber l?. enters the restricted opening 24 in the element 23 a pressure drop occurs across said opening. This results in a dissipation of energy so that the velocity or" the iluid Bowing through the bore 2l of the nozzle tube Ztl is reduced. The discharge end 22 of theV nozzle tube then controls the velocity of the stream which is discharged therefrom. Each nozzle i9 is mounted within the bit body to directy the stream discharged therefrom onto the cutter teeth of the cutter therebelow, and it is evident that the stream so discharged is of lesser volume and lesser velocity than the streams discharged from the nozzles i6. It is also evident that by controlling the size of the tube, the diameter of the control orifice 24 and the diameter of the discharge end 22, a stream of any desired velocity and volume may be obtained.

The nozzles 16 and 19 may be mounted in the bit in any suitable manner and as illustrated extend through openings in the bit body being welded in iinal position therein. Ordinarily, the nozzles 16 and 19 are not mounted in the same plane and therefore Figure 3 is a schematic view which does not intend to show the nozzles 16 and 19 in their exact or true relationship; the schematic view is provided for purposes of illustration only to show the construction of each of said nozzles.

From the foregoing it will be seen that a nozzle arrangement is provided whereby a stream or streams of high volume high velocity may be directed upon the bottom of the hole while a stream or streams of lesser volume and lesser velocity may be directed upon the cutters, with all nozzles having a common source of fluid supply. In this manner the high velocity jets or streams impinging upon the bottom of the hole assists the cutters in the drilling operation, while the lesser Volume low velocity streams maintain the cutters in clean condition without cutting out the teeth or causing excessive wear thereof.

A modification of the invention is schematically illustrated in Figure 4 wherein nozzles 19a, functioning in a manner similar to nozzles 19, are constructed of a tube 20a having its upper end 25 closed. Restricted openings or orifices 26 extend radially through the tube 20a and are in communication with the chamber 12 of the bit body. The orifices 26 function in the same manner as the orifice 24 of the first form in that a pressure drop is created thereacross which results in a reduction of the velocity of the flowing fluid. The same principle of operation which is a dissipation of the energy is utilized in the form shown in Figure 4. By controlling the size of the orifices 26, the velocity of the discharging stream is controlled.

In Figure still another modification is illustrated. In this form a nozzle assembly 19b which may be substituted for the nozzles 19 and 19a of the forms heretofore described, comprises a tube 27 having a tapered restricted bore 28 extending from the chamber 12 of the bit body to the area above the cutters 14. A tapered collar 29 surrounds the discharge end 28a of the tube 27, this collar being attached through supporting arms 30 to the bit body. As indicated by the arrows, the fluid stream discharging from the tube 27 will create a suction effect at the upper end of the tapered collar 29 and will function to draw additional fluid into the upper end of the collar. This additional volume of fluid admixing with the stream ejecting from the tube 27 will act to dissipate the energy of the stream and will result in a low velocity stream discharging from the lower end 29a of the collar.

In all forms of the invention the high velocity high volume streams are discharged onto the bottom of the hole through the nozzle 16 and the particular volume and velocity of said streams is controlled by the construction of said nozzles; the streams of lesser volume and low velocity are discharged through the nozzles, which may be constructed in the manner of the nozzles 19, 19a or 19b as shown in Figures 3, 4 and 5, respectively, and such low velocity streams function to maintain the cutters in a clean condition to assure maximum cutting efficiency.

The foregoing disclosure and description of the invention is illustrative and explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction may be made, within the scope of the appended claims, without departing from the spirit of the invention.

Having described the invention, we claim:

l. The combination with a drilling bit including a bit body having a cutter thereon of a nozzle assembly including, a tubular nozzle conduit having a tapered bore for discharging a high velocity stream onto the bottom of the well bore, a second tubular element having a substantially constant diameter bore for discharging a low velocity stream upon the cutter, and means at the inlet end of the latter conduit for restricting the fluid enter-- ing said latter conduit.

2. The combination with a roller type rock bit of a nozzle assembly including, a plurality of high velocity nozzles for discharging a high velocity fluid stream onto the bottom of the well bore, each including a tubular conduit having a tapered bore, a plurality of low velocity nozzles for discharging a low velocity fluid stream onto the roller bit each low velocity nozzle comprising a tube having a bore of substantially constant diameter and means at the inlet end of said tube for restricting the flow of fluid into the tube to create a pressure drop across said restriction.

3. The combination with a roller type rock bit of a nozzle assembly including, a plurality of high velocity nozzles for discharging a high velocity fluid stream onto the bottom of the well bore, each including a tubular conduit having a tapered bore, a plurality of low velocity nozzles for discharging a low velocity fluid stream onto the roller bit each low velocity nozzle comprising a tube having a tapered bore and an annular collar surrounding the discharge end of said tube and having its bore tapered and spaced from the exterior surface of the tube.

4. A drill bit including a bit body having a cutter thereon, a nozzle in the bit body for discharging a fluid stream to one side of said cutter, and a second nozzle in said body for discharging a fluid stream upon the said cutter, said second nozzle comprising a tube having a cap on the inlet end thereof and having an orifice extending radially through the wall of said tube near the inlet end thereof, to reduce the velocity of the fluid stream discharging from the said second nozzle.

5. A drill bit including, a bit body having a cutter thereon, a nozzle in the bit body for discharging a fluid stream to one side of said cutter, and a second nozzle in said body for discharging a fluid stream upon the said cutter, the second nozzle comprising a tube having a closure on the inlet end thereof, the inlet end of said second nozzle having a plurality of orifices therethrough, the said orifices being arranged so that fluid passing inwardly through one of said orifices will impinge the fluid passing inwardly through the other of said orifices,

References Cited in the file of this patent UNTED STATES PATENTS

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