US3419220A

US3419220A - Nozzles for abrasive-laden slurry

Info

Publication number: US3419220A
Application number: US597941A
Authority: US
Inventors: Robert J Goodwin; Joseph L Pekarek; Paul W Schaub
Original assignee: Gulf Research and Development Co
Current assignee: Gulf Research and Development Co
Priority date: 1966-11-30
Filing date: 1966-11-30
Publication date: 1968-12-31
Anticipated expiration: 1985-12-31

Description

1968 R. J. GOODWIN ETAL 3,419,220

NOZZLES FOR ABRASIVE-LADEN SLURRY Filed Nov. 30, 1966 FIG.|

INVENTORS ROBERT J. GOODWIN JOSEPH L. PEKAREK PAUL W. SCHAUB United States Patent M 3,419,220 NOZZLES FOR ABRASIVE-LADEN SLURRY Robert J. Goodwin, Oakmont, and Joseph L. Pekarek and Paul W. Schauh, Penn Hills Township, Allegheny County, Pa., assignors to Gulf Research & Development Company, Pittsburgh, Pa., a corporation of Delaware Filed Nov. 30, 1966, Ser. No. 597,941 7 Claims. (Cl. 239-591) ABSTRACT OF THE DISCLOSURE The invention comprises a nozzle made of two or more different materials, arranged in tandem, so that a section of the nozzle subjected mostly to a particular type of wear can be made of a particular material more highly resistant to that type of wear. Means are disclosed to lock the nozzle in a drilling bit.

This invention pertains to nozzles, and particularly to a composite nozzle for use in hydraulic drilling of wells by means of high velocity jets of an abrasive-laden slurry, and to means for retaining such a nozzle in a hydraulic drilling bit.

Nozzle war is a critical factor in the so-called jet drilling method, in which method the borehole is created substantially entirely by the high velocity jets of abrasiveladen slurry, Hydraulic jet drilling allows substantially higher penetration rates than are obtainable with conventional rotary bits. Rotary bits create the borehole by mechanical action between cutting elements of the bit and the formation.

However, in the jet drilling method the highly erosive nature of the slurry passing through the nozzle tends to erode the nozzle rapidly. Drilling must stop when the nozzles become so eroded and enlarged that the pumping equipment is no longer able to develop the required cutting jet velocity through the nozzle exits because of the pressure losses associated with the higher flow rates through the pipe required by the enlarged nozzles. When this occurs, it is necessary to pull the drill string and bit out of the hole, replace the bit with a new bit, or replace the nozzles, and then reinsert the drill string. This is a time consuming operation, and a very expensive one considering the high cost of maintaining a drilling rig and its crew in the field. Hence, it is a primary object of the present invention to provide an improved nozzle suitable for use in jet drilling which will have a relatively long useful life.

The invention comprises a nozzle composed of a plurality of sections arranged in tandem. Each section is fabricated from a different grade of material, each having a particularly physical characteristic advantageous at the location in the nozzle in which that section is located. Many different materials and combinations of materials could be used. Some examples are diamond, ceramic materials, boron carbide, and tungsten carbide.

Tungsten carbide has been found to be a particularly suitable material for fabricating nozzles used in jet drilling. However, there are various different grades of tungsten carbide and each of these grades has a different set of physical characteristics. The particular characteristics with which the invention is concerned are abrasion resistance and impact resistance. That is, resistance to wear from abrasion or from impact between the nozzle material and the particles of abrasive in the slurry. -It has been found that certain sections of the nozzle are subject more to wear from impact and certain other sections are subject more to wear from abrasion, than other sections. The entrance end of the nozzle reduces the cross-sectional area of the flow stream to increase its 3,419,220 Patented Dec. 31, 1968 velocity, and is subjected to impact from the abrasive particles in the slurry. The exit end of the nozzle, which is formed into a cylindrical throat portion, is subjected more to abrasion wear because of the laminar like flow of the slurry therethrough. The central portion of the nozzle, wherein the flow stream is narrowed down in preparation for its passage through the throat, is subject to both impact and abrasion wear, but to degrees less than the entrance section and the exit throat section, respectively.

The invention also comprises a method and apparatus for mounting the nozzle in a jet drilling bit, which comprises means to hold the nozzle sections locked into a suitable opening in said bit.

In the accompanying drawing forming a part of this disclosure: FIG. 1 is a front elevational view of a nozzle embodying the invention; FIG. 2 is a longitudinal crosssectional view taken on line 22 of FIG. 1; and FIG. 3 is a partial, vertical, cross-sectional view through a bit showing the nozzle mounted therein.

Referring now in detail to the drawing, 10 designates a nozzle embodying the invention. Nozzle 10 is formed with a longitudinal through opening 12. Opening 12 defines the operating characteristics of the nozzle, is shown diagrammatically only, and is not intended to representa preferred internal cross-sectional shape. As will be obvious, the invention is applicable to an elongated nozzle having an internal cross-sectional shape.

Nozzle 10 comprises an exit section 14, a central section 16, and an entrance section 18. The direction of flow through the nozzle is indicated by the arrows marked Q, representing the flow direction of the abrasive-laden slurry.

Each of the

sections

14, 16, and 18 is hollow, and the three sections are arranged in tandem to form through opening 12. The sections may be joined together by any suitable means such as silver solder, brazing or the like when it is desired to fabricate the nozzle alone, or they may be held together in a bit by suitable locking means, as described below. Exit section 14 is is fabricated of a grade of tungsten carbide having a high resistance to wear from abrasion. Entrance section 18, which is the section of the nozzle first subjected to the impact force of the abrasive particles in the slurry as the flow stream is reduced in cross-sectional area, is fabricated of a different grade of tungsten carbide characterized by a high resistance to wear from impact. The central section 16 is fabricated from a third grade of tungsten carbide having its abrasion resistance and impact resistance wear characteristics balanced, with the impact wear resistance characteristic being less than that of the material forming entrance section 18, and with the abrasion resistance wear characteristic being less than that of exit section 14. At present, a material high in both abrasion and impact resistance is not available.

Nozzle 10 is shown comprised of three sections, but it is to be understood that this is by way of example only, and a nozzle comprising two sections would be used in a shorter nozzle where the over-all length is such that there is in effect no central section, and the flow stream, as far as the wear characteristics with which the invention is concernd, goes directly from the entrance section to the exit section.

Suitable grades of tungsten carbide are manufactured by Kennametal Company of Latrobe, Pa. These various grades are described in their catalogue entitled, Properties of Kenn-ametal Hard Carbide Alloys. Copyright 1964, wherein there can he found tables listing numerical values for physical characteristics of the materials manufactured by said company including abrasion resistance and impact resistance. The cited catalogue also sets forth the test conditions by which these values were obtained. Referring to said catalogue at page 10, a suitable grade fo tungsten carbide for use in section 14 is designated grade K701; for section 16, grade K8; and for section 18, grade K68.

Boron carbide and diamond are also suitable materials for use in exit section 14, because both of these materials are very resistive to Wear from abrasion, and the fact that they are both brittle and hence not resistive to wear from impact, does not detract from their usefulness in the exit section.

Referring to FIG. 3, there is shown a diagrammatic cross-sectional view through a corner of a jet drilling bit showing the invention in use. It will be understood that the showing of FIG. 3 is intended to be illustrative only of the method and means of mounting the nozzle of the invention in a jet drilling bit, and is not to be limited to vertical as shown, since nozzles are mounted at various angles in practice. Jet drilling bit 20 comprises a bottom Wall 22 and a side wall 24, which together form a hollow slurry receiving chamber 26 within the bit. Bit 20 also comprises a bottom plate 28 formed of hard, abrasion resistant material, to protect the bit from excessive wear by backsplash of abrasive particles from the bottom and side walls of the borehole.

Mounted in bottom wall 22 and bottom plate 28 is a nozzle 10a, similar to the nozzle 10 of FIGS. 1 and 2', except that exit section 14a of nozzle 10a is formed with an external taper 30 which cooperates with a mating female taper formed in bottom plate 28 to limit movement of the nozzle 10a downwardly and outwardly of the bit, to hold the nozzle in place. Nozzle 10a also comprises a center section 16a and an entrance section 18a similar to those respective parts of nozzle 10. Above tapered portion 30, bottom plate 28 and bottom wall 22 are formed with a cylindrical opening 32 of a suitable diameter to snugly fit the external diameter of nozzle 10a. Means are provided to hold nozzle 10a firmly in place in

composite opening

30 and 32, and yet to selectively permit removal of the nozzle if it should become worn. To this end a nozzle locking sleeve 34 is provided. Sleeve 34 comprises an internal diameter 36, substantially equal to the external diameter of nozzle 10a, extending through substantially its entire length. At its upper end, sleeve 34 is provided with an overhanging lip or flange 38 having an internal diameter smaller than the external diameter of nozzle 10a, but larger than the largest diameter of the internal longitudinal opening of the nozzle. Thus, flange 38 overlies the upper end of the nozzle to hold the nozzle firmly in place against taper 30, and yet does not interfere with the flow stream of the abrasive-laden slurry through the nozzle. The lower end of sleeve 34 is formed with screw threaded 40 which cooperate with mating threads formed in an opening formed in bottom plate 22 above opening 32. The upper external portion 42 of sleeve 34 above threads 40 may be formed into a hex nut, or with holes for a spanner wrench, or with any other suitable means, for tightening the sleeve by means of threads 40 to lock the nozzle in place.

The sections 14a, 16a and 18a of nozzle 10a may be held in place solely by tension applied by locking sleeve 34. In applications wherein higher pressures and/or severely adverse conditions are encountered, brazing or other joining means between the sections may be employed.

The invention has advantages over prior nozzles fabricated all in one piece. It is simpler and less expensive to fabricate a nozzle in sections rather than in one piece, and easier to control the configuration of the internal profile. Also, it is possible to disassemble a composite nozzle and replace only the section that is worn, which is impossible in a one piece nozzle. This advantage is enhanced in those applications where the sections of the nozzle are held together solely by the force of the locking means, since the step of taking apart the solder or brazed joints is avoided. Thus, in effect, a reusable nozzle is provided, at a saving of approximately one-third the cost of a new nozzle.

While the invention has been described in some detail above, it is to be understood that this detailed description is by way of example only, and the protection granted is to be limited only within the spirit of the invention and the scope of the following claims.

We claim:

1. A bit for drilling earth boreholes by means of high velocity jets of an abrasive-laden slurry having an internal slurry receiving chamber, comprising an elongated nozzle consisting of a plurality of nozzle sections arranged in tandem, said nozzle sections being formed with aligned openings to form a longitudinal through opening through said nozzle, said plurality of sections including an entrance nozzle section and an exit nozzle sections, said exit nozzle section consisting of a first material having a high resistance to wear by abrasion, said entrance nozzle section consisting of a second material having a high resistance to wear by impact, said nozzle including a central nozzle section disposed between said exit and entrance nozzle sections, said central nozzle section consisting of a third material having a resistance to wear by impact less than that of the material constituting said entrance section and a resistance to wear by abrasion less than that of the material constituting said exit section, and locking means to lock said nozzle in said bit with the entrance end of said entrance section Within said chamber and with the exit end of said exit section outside of said chamber.

2. The combination of claim 1, said locking means comprising a locking sleeve formed with radially inwardly ext-ending flange means cooperable with the entrance end of said entrance section, said flange means being positioned outwardly of the entrance opening of said entrance section, whereby said flange means are positioned out of the flow stream of the slurry entering said nozzle, and said locking sleeve being formed with a screw thread cooperable with a mating thread in said bit to lock said nozzle in said bit.

3. The combination of claim 1, means on said bit cooperable With means on said exit section to limit movement of said nozzle with respect to said bit in one direction, said movement limiting means comprising mating tapers formed on the outside of said exit section and in a suitable opening formed in a wall of said bit defining said chamber.

4. The combination of claim 1, means to join the exit end of said entrance section to the entrance end of said central section, and means to join the exit end of said central section to the entrance end of said exit section.

5. The combination of claim 4, said joining means comprising silver solder.

6. A bit for drilling earth boreholes by means of high velocity jets of an abrasive-laden slurry having an internal slurry receiving chamber, comprising an elongated nozzle consisting of a plurality of nozzle sections arranged in tandem, said nozzle sections being formed with aligned openings to form a longitudinal through opening through said nozzle, said plurality of sections including an entrance nozzle section and an exit nozzle section, said exit nozzle section consisting of a first material having a high resistance to wear by abrasion, said entrance nozzle section consisting of a second material having a high resistance to wear by impact, and locking means to lock said nozzle in said bit with the entrance end of said entrance section within said chamber and with the exit end of said exit section outside of said chamber, said locking means comprising a locking sleeve formed with radially inwardly extending flange means cooperable with the entrance end of said entrance section, said flange means being positioned outwardly of the entrance opening of said entrance section, whereby said flange means are positioned out of the flow stream of the slurry entering said nozzle, and said locking sleeve being formed with a screw thread cooperable with a mating thread in said bit to lock said nozzle in said bit.

7. A bit for drilling earth boreholes by means of high velocity jets of an abrasive-laden slurry having an internal slurry receiving chamber, comprising an elongated nozzle consisting of a plurality of nozzle sections arranged in tandem, said nozzle sections being formed with aligned openings to form a longitudinal through opening through said nozzle, said plurality of sections including an entrance nozzle section and an exit nozzle section, said exit nozzle section consisting of a first material having a high resistance to wear by abrasion, said entrance nozzle section consisting of a second material having a high resistance to wear by impact, locking means to lock said nozzle in said bit with the entrance end of said entrance section within said chamber and with the exit end of said exit section outside of said chamber, and means on said bit cooperable with means on said exit section to limit movement of said nozzle with respect to said bit in one direction, said movement limiting means comprising mating tapers formed on the outside of said exit section and in a suitable opening formed in a wall of said bit defining said chamber.

References Cited M. HENSON WOOD, JR., Primary Examiner.

M. Y. MAR, Assistant Examiner.

US. Cl. X.R.