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Publication numberUS2661065 A
Publication typeGrant
Publication dateDec 1, 1953
Filing dateMay 24, 1948
Priority dateMay 24, 1948
Publication numberUS 2661065 A, US 2661065A, US-A-2661065, US2661065 A, US2661065A
InventorsMccoy Carl J
Original AssigneeMccoy Carl J
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Perforation cleaning device
US 2661065 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

Dec. 1, 1953 c. J. MGcoY PERFORATION CLEANING DEVICE 2 Sheets-Sheet l Filed May 24. 1948 lllllllllll-IIIIIIIIIIIIIII IAN..n

Dec. 1, 1953 c. J. MCcoY PERFORATION CLEANING DEVICE 2 Sheets-Sheet 2 Filed May 24, 1948 Patented Dec. l, 1953 I UNITED STATES PERFoRATIoN CLEANING DEVICE Carl J. McCoy, Orcutt, Calif. 4 Y Application May 24, 1948, Serial No. 28,786

7 Claims.

This invention relates to a device for cleaning "perforations in a casing of the type employed in wells and is particularly directed to apparatus for continuously cleaning the casing perforations during the operation of the well pump for pumping fluid from the well. This device finds particular usefulness in connection with the production of petroleum from oil wells.

.This application is a continuation in part of my copending application for Brush for Well Casings, Serial No. 651,449, filed March 2, 1946, now abandoned.

The principal object of this invention is to provide aV device for automatically cleaning casing. perforations during operation of the pump for'raising fluid from the well, the device being caused to travel vertically in the well by reason of the relative movement between the tubing and casing occasioned by operation of the pump at the lower end of the tubing.

Another object is to provide a cleaner device of this type which travels upwardly along the tubing for a predetermined distance and then reverses its direction of ytravel automatically during normal operation of the well pump.

Another object is to provide a cleaner device having its spring iingers movable into and out of casing perforations which are yieldable to permit movement of the cleaner device in either direction within the casing. l

Another object is to provide mechanism for kautomatically moving a cleaner device within perforated casing in a step by step manner in accordance with relative movement between the tubing and casing occasioned by operation of the well pump.

A more particular object is to provide a novel form ef'releasable clutch construction which is operable to propel the cleaner device in either direction.

Another object is to provide a novel form of mounting for the spring ngers which are adapted to engage Within the perforated slots in the casing.

Other objects and advantages will 'appear hereinafter.

In the drawings:

Figure 1 is a sectional side elevation partly broken away showing a preferred embodiment of my invention positioned within a well bore.

AFigure 2 is a side elevation partly lin section 'on an enlarged vscale illustrating details of construction of a cleaner device embodying my invention. y

Figure 3 is an elevation View partly broken away taken in thedirection of the lines 3 3 as shown in Figure 2.

Figure 4 is a sectional plan view taken substantially on the lines 4 4 as shown in Figure 2.

Figure 5 is a sectional plan view taken substantially on the lines 5 5 as shown in Figure 2.

Figure 6 is a sectional detail taken substantially on the lines 5 6 as shown in Figure 1,

Figure 7 isa sectional perspective view illustrating the mounting of the spring ngers on the cleaner device.

Figure 8 is a perspective view partly broken `away showing the body of the cleaner device.

Figure 9 is a sectional elevation taken substantially on the lines 9 9 as shown in Figure 3. Figure 1G is a perspective view of a subassembly including the clutch plate and releasable latching mechanism. l

Figure` 11 is a view similar to the upper portion of Figure 10- showing the upper latching spring in compressed position.

Figure 12 is a partial sectional plan view taken substantially on the lines I2 I2 as shown in Figure 9.

Figure 13 is a partial sectional plan view of a .portion of the apparatus shown in Figure 4 but with the latching lug rotated to release position.

Referring to the drawings', the casing Ill within the well borevmay be provided with the usual perforated slots I which are adapted to allow well fluid to enter the casing I0. A well pump generally designated I2 and shown diagrammatically in Figure 1 may be positioned within the lower end of the tubing I3 which extends downwardly within the bore hole from the surface.

-The tubing I3 constitutes an eduction conduit for well fluid and is made up of sections conneet-ed by threaded collars I4. A jointed sucker rod I5 extends downwardly within the tubing I3 and is connected at I5 to reciprocate the pump plunger Il within the pump barrel I8.

The usual traveling valve I9 is provided on the plunger I 1, and the standing valve 20 is mounted at the-lower end of the barrel I8. 'Ihe pump I2 may-.take 'any suitable or conventional form and is shown diagrammatically for illustrative purposes-only. The sucker rod I5 is reciprocated at the surface by means' of a suitable pumping jack (not shown). When the sucker rod I5 moves upwardly, the weight of the well uid in the tubing I3 ,is carried on the pump plunger I1. When the sucker rod I5 moves downwardly', however, the weight of the well fluid within the tubing 'I3 is carried by the tubing I3, since the 55 foot valve 20 remains closed. The alternate increase and decrease of weight occasioned byactuation of the pump I2 causes the tubing length to lengthen and contract in accordance with the operating strokes of the pump plunger II. Since the tubing may be several thousand feet in length, the relative movement between the tubing I3 and casing I2 near the lower end of the tubing may amount to several inches or more for each stroke of the pump.

In accordance with my invention I make .use of the alternate stretch and contraction of the tubing relative to the casing for moving a perforation cleaner vertically within the casing I0. rllhe perforation cleaner device is generally designated 2I and is adapted to travel on the tubing 1I3 "between spaced coupling collars I4. Although .only one perfo-ration cleaner device is shown and described, it will be understood that additional `devices 2I may be installed on the tubing between each pair of coupling collars I4 throughout the length of the perforated casing Ii). It will be understood 'by those 'skilled in the ,art that the perforated casing I5 is carried latthe lower end of imperforate casing extending from the well surface.

The -cleaner device 2-I comprises `afbody 22 :having -a Vpair of vertically spaced end flanges '23 vextending by yvertically extending bars v24, 25 and 26. A tubular 4guide 21 projects :from each of the end flanges23 4andis provided with threads '28 at 'its projecting end. -Each of the tubular guides 21 is provided with a longitudinal slot 29. The ftubular guides 2"I are adapted to encircle the tubing I3 for `sliding movement thereon. Upper and lower brush 'assemblies generally designated and 3 I are adapted-tobe mounted lon the tubuflar guides 21. Each of 4these brush 'assemblies yincludes a knut 32 having internal threads 33 adapted to engage the threads 28 on 'the outer #end of the 'tubular guides 21. Anadapter 34 rests :against each of the end flanges 23 and is provided with an annular shoulder Vadaptedto receive one end -of the spacer "36. IThe upper lend of -the spacer `r36 is received 'against a similarshoulder 37 provided on the nut 32. description it will be Iunderstood that `the yspacer 36 is clamped between the -annular'shoulders 35 and 31. -A plurality of slots 38 'areformed in the spacer '35, adapter I34 and `nut 32, las-shovvn clearly iin 'Figure i7. A plurality -of yspring elements 39 lare lmounted on the spacer 36, and each is provided with a pair of vertically spaced prongs 4U "projecting `radially youtwardly thro-ugh the slots .38. "The spring elements 39 each may be formed froma single length of spring wire having a loop .f

.4-'I .at the innerend ofieac'h Aof the projections 40 :and :a central loop '42 which L.projects outwardly through an aperture d3 provided in 'the spacer 35,. .A retainer v-wire .44 extends vc'ircumf'erentially :around the spacer (.36 :and 'thro-ugh the central .loops -142 to .prevent displacement of 'the spring elements 39. Adjacent spring elements y39 may fhave their central loops 42 pos'iI'iom-til at different elevations iin order that the apertures 543 may be=positionedin two parallel rows and :thus vavoid ,undesirable weakening of the spacer 36 which would zoccur if all :of :the vapertures 43 vwere 'located i-n asingle'row. Accordingly, a second -rre- .tainer "wire V45 lmay Lbe employed to ysecure :alternate spring 1elements 39 'in:positiononfthe spacer v315.

`The:opposite-.ends ofthe clearance Lslots 38 may .be Ycut son `an .angle tas vshown at 46 in v'order fte limit .the extent of `*the :angular 'movement of 'the projections 40. Movement of the cleaner :device From the above .1%.

2I vertically within the perforated casing I0 causes the projections to extend into the perforations II and thereby free the perforations of sand, grit or other foreign matter, thus permitting entrance of well iluid into the casing I0. As shown in Figure 6, the projections 40 engage the inner Wall of the casing IB until such time as movement of the cleaner device 2I brings the projection opposite one of the elongated slits or "perforations I-I. The ,projection .40 vthen moves into the 'perforation I'I vand is carried upwardly with the cleaner device 2l. The position of the ,projection 40 when operating within the perfora- .tion is shown .by the dotted lines 40a in Figure :6. As 'the cleaner device 2I continues to move relative tothe casing IIJ, the projection 4B strikes vthe end of the elongated slit or perforation and through .which the tubing 'I3 extends. The -opening Y48 'is shaped so .that .itgrips lthe surace .of the tubing I3 when the plate 4'! `is vtilted -to a suiiic'ient angle with respect thereto. 'The plate 41 is provided with a projecting portion 49 :adapted to be received within a horizontal slot '.59 provid-ed in the bar '24 on the 'body :22. 'On

"the opposite side of 'the clutch plate v4'! from the projection 49 is an ear 5I provided with an 'opening 52. The ear 5I .is 'adapted to extend into 'a central opening 53 provided in clutch control Yelement 5 4. 'This clutch .control element 'is Amounted between 'a pair of axially aligned oppositely extending vertical tubes 5,5 which are yintegrally connected to A'the element 54 and are `adapted lfor sliding movement 4relative to a pair of axially aligned lguide pins 53 Acarried .on the end ilanges 23.

The assembly uinclud-ing `the *tubes -55 and the cclutch control element "5'4 is hereinafter 'general- 'ly designa-'ted `the control ymember y'.il. Flan'ges 58 and 59 are Aprovided at opposite ends of the :control member 5'I and adapted lto engage Ythe end iianges v2? on the body 22. A pair of gripper 4springs 556) `and 6l are mounted on the control `member 51 within the clutch control element 54. A pair of cross pins Ii-2 extending through the tubes contact one end of each -of the springs. :the other `end of each spring engages the fear :55| fon the clutch plate f4'I. If desired, the `.wire at one lend of 'each of the coil springs B0 :and v6I may be Aprojected through the 1aperture 52 in the ear 5I in order to prevent disassembly of the ear from its position 4'between the gripper springs. ``The construction just described provides a floating 'mounting for the ear 51I between the opposed compression coil springs 6Fl fand Eil.

A'paircf :shifter springs '63 yand 64 encircle the Etubes 55, 'and each contacts la shoulder 65 and E6 provided on the clutch control element 54.

AThe upper end of the coil spring 63 rests yagainst a shoe 61 encircling the upper tube 55, and the lower end of the spring E4 contacts a similar shoe 58 encircling the lower tube 55. The shoe AII carries an upwardly extending trip finger 69 and the lower Ishoe 68 carries a downwardly extending trip rringer 19. rlhe fingers 69 and lll extend through slots 29 provided on the body `guides 21 and project outwardly beyond the position of the nuts 312.

clutch control element 54 and provided with a i bevelled surface 18. Compression of the spring 63 lfrom the position shown in Figure l() to the position shown in Figure 11 serves to bring the vcooperating bevelled surfaces 13 and 16 into engagement, thereby rotating the clutch control element 54 in a clockwise direction as viewed in Figure 13. In similar fashion, compression of lthe lower shifter spring 54 serves to bring the with the ear 5I at a higher elevation than the horizontal slot 5I).` When the latching lug 19 is positioned in engagement with the lower notch 8|, the clutch plate 41 assumes the dotted line position 41a, as shown in Figure 2. In operation the cleaner device generally designated 2| is installed on one or `more sections of tubing I3 between coupling collars I4 and is run into the well with the tubing string so asv to position the cleaner adjacent the perforated casing I0.

The tubing carries the pump I2 at its lower end.

Reciprocation of the sucker rod I5 from the surface serves to reciprocate the pump barrel I1 vand to cause well fluid to be pumped upwardly through the tubing I3 to the surface. As the tubing alternately lengthens and shortens due to the action of the pump I2 as set forth hereinabove, the lower end of the tubing I3 reciprocates within the `relatively stationary casing I0. The projections 40 of the spring elements 39 engage within the inner wall of the casing and extend into' the perforations II. Assuming that the clutch plate 41 is in the full line position shown in the drawings, downward movement of the tubing I3 relative to the perforated casing I0 releases the gripping action of the plate 41y on the surface of the tubing I3 and allows the tubing to descend. The cleaner device 2| remains in place and does not descend with the-tubing, because the projections 48 offer sufficient frictional resistance within the casing I0 to overcome the action of gravity. i When the tubing I3 moves upwardly the clutch plate 41 grips the surface of the tubing I3 and the entire cleaning device 2|, including the body 22 and brush assemblies 3|! and 3|, is carried upwardly for substantially the full amount of upward movement Aof the tubing I3. Downward movement of the tubing I3 again releases the gripping action of the plate 41, and the cleaner device 2| remains in place until the next upward Y movement of the tubing. This action continues with the cleaner device 2| moving upwardly step by step until theupper end of the finger |59 engages under the connecting collar I4. Subsequent vupward movement of the cleaner device with the 6 subsequent downward movement of the tubing I3 causes the finger 69 and its shoe 61 to compress the upper shifter spring 63. This action eventually brings the bevelled'surfaces 13 and 16 into engagement, thereby rotating the control member 51 and moving the latching lug 19 out of the upper notch 88 on the vertical bar 25. The energy' stored within the compressed coil spring 63 then acts to shift the control member 51 downwardly to bring the flange 59 into engagement with the end flange 23 on the body 22. The. .latching lug 19 enters the notch 8| in the vertical bar 25.

The upper spring 63 provides torsion to rotate the control member 51 in a counterclockwise direction as viewed in Figure 13 to maintain the latching lug 19 within the lower notch 8|. The torsion may be supplied in any desired manner, and as shown I prefer to employ the upper spring 63 for this purpose. rhe upper end 82 of the wire forming the spring 63 may bear against one side of the shoe 61, and the lower end 83 of the wire may be anchored within a hole 84 provided in the wall of the upper tube 55 adjacent the clutch control element 54.

When the clutch plate 41 assumes the position shown in dotted lines in Figure 2 and designated 41a -by reason of engagement of the latch lug 19 with the lower notch 8|, the cleaner device 2| begins its movement downwardly within the casing I. Upward movement of the tubing I3 serves to release the gripping action of the plate 41 on the surface of the tubing I3, permitting it to move upwardly without moving the cleaner device 2|. Downward movement of the tubing I3, however, causes the clutch plate 41 to grip the tubing I3 and to move the cleaner device 2| downwardly for substantially the full stroke of vthe lower end of the tubing. The cleaner device 2| therefore moves downwardly step by step as the lower end of the tubing reciprocates, and this action continues until the finger 10 which extends downwardly below the lower nut 32 engages a lower coupling collar I4 on the tubing. The finger 19 is moved upwardly on the next upward stroke `of the tubing and collar I4, and this action serves to raise the shoe 68 to compress the lower shifter spring 64.

Compression of the shifter spring 34 serves to bring together the bevelled surfaces 14 and 18 and thereby rotate the control member 51 in a clockwise direction as viewed in Figure I3 to release the latch lug 19 from the lower notch 8|. 'The energy stored in the lower shifter spring 64 then shifts the control member 51 upwardly, and the torsion action of the upper spring 63 rotates the member 51 to bring the latching lug 19 into engagement with the upper notch 89. The clutch plate 41 reassumes its full line position as shown in Figure 2, and the cleaning device again proceeds upwardly along the tubing I3, thus repeat- 'ing the cycle.

The gripper springs 68 and 6| for the ear 5| on the clutch plate 41 provide a floating mounting for one end of the clutch plate 41 so that it may move sufficiently to grip and lrelease the pipe 'I3 in the manner just described. The brush assemblies 39 and 3| by moving continuously between thecoupling collars 4 serve to keep the 'casing perforations free of obstructing material to facilitate iiow of well iiuid into the casing I0. The spring mounted projections 4I! move inwardly about the center loops 42 to permit reversal of movement and thereby cause the projections to be moved to a trailing position. The resilience :2,1661 ,oo-s

roi 'the spring elements 53B plus the spring action obtained by the Yloops #ll-I .and 42 insures an eec- `tive cleaning .action 'without resulting in any permanent deformation :of the spring elements 553. The use of my .improved cleaner device 2| 'which `operates automatically 'with the alternate :stretch and contraction of .the tubing serves to keep the casing periorationslclean while the pump i2 .is operating. The expense and time required tor periodic removal of :the 'pump in order to -ciean .the casing perfiorat'ions :are eliminated with consequent increase in overall 'production from the well.

Having fully-described my invention, 'it is to be understood that I :do not IWisin to be limited to 4the details herein set forth, but my invention is .-.o the -frulrl :scope of 'the appended claims.

'1, A :device tor .cleaning perfora'te well casings comprising iin combination: .a body axially movable :alongva string roi'vvell tubing through ra string o1" perforated casing sections; a collar secured to Ethebody, fsa-id 4collar .having-.a row of slots spaced around its periphery a Jacent an end thereof .and an aperture corresponding to Leach slo springs mounted within the collar, each spring comprising fa 'main portion having Aa central loop therein which Aprojects through .one :of said apertures, and :anend portion projecting outwardly through the corresponding slut in the collar for engaging the casing; :and .a :continuous retainer wire member encircling the periphery of `said cellar and threaded through ysaid central ioops, thereby zsecuning :springs to said collar.

.2.1i `device tor cleaning casing perforations comprising in combinations: .a body slidably monntablefupon a -reciprocable:str-ing of well tubing for introduction therewith into :a well casing; nge-rscarried by the body tor'brushing and rrictionally 'dragging on .the interi-or :of the oasingto vclear obstructions from perforations therein; 1a clutch `member carried -by the body and ,engageable with said tubing, said clutch member being movable between :a iirst position permitting upward movement of 'said body relative -to said @tubing but resisting .relative downward movement thereof, and :a ysecond position wherein the action of said clutch member is reversed; la device connected to the clutch member for moving the lclutch member between its lrst :and second positions; stops positioned at predetermined 'points along the length of 'the string of tubing; `means carried by the body .and movable thereby .into lengagement with `the Astops for actuating `said device to reverse the clutch.

T3. in .a well apparatus wherein a well casing is provided vwith a perforated zone, an eduction tube is suspended in the casing and is provided with fa reciprocating pump and wherein on operation of said pump, the region of said eduction tubing in-'the zone :of said perforations is caused to reciprocate relative to the casing .due to variation in uid loads impressed on the tubing, the combi-nation of a well cleaner, comprising: a frame structure adapted to be slidably mounted on said eduction tubing in the region of said perforations; a plurality of perforation cleaning fingers carried by said frame structure and engageable with the walls of said casing and capable of penetrating the openings therein; said fingers providing a yieldable frictional connection between said frame structure and said casing tending to maintain said frame structure ixed relative to .said casing; and a clutch means carried .by :said frame structure adapted to engage said eduction tubing to secure ysaid frame structure relative thereto during movement of said eduction tubing relative to said casing 'in one direction, and to disengage said eduction tubing .on movement of said tubing relative to said casing in the opposite direction, whereby said frame structure tends to travel along said casing and eduction tubing 'as said tubing is reciprocated.

4. 'In a well apparatus wherein a well casing is provided lwith a perforated zone, an eduction tube is suspended in the casing and is provided with a reciprocating pump 4and wherein on operation of said pump, the region of said educ- Vtion tubing in the zone of said periorations vis caused to reciprocate relative `to 'the casing `due to variation in iiuid loads impressed on the tubing, the combination of a well cleaner, comprising: a iframe structure adapted to be s'lidably mounted on said eduction tubing in the region of 'said perforations; a plurality of perforation cleaning fingers carried by said frame structure and engageable with the walls of said casing and capable -oi penetrating the openings therein; said ngers providing 'a yieldable frictiona'l connection between said frame structure and said casing tending to maintain said frame structure nXed relative to said casing; and a rclutch means carried by said frame structure adapted to engage said eduction tubing to secure said frame structure relative thereto during movement of said eduction tubing relative to said casing in one direction, and to disengage lsaid eduction 'tubing on movement of said tubing relative to said casing in the opposite direction, whereby said frame structure tends to travel along said casi-ng vand eduction tubing as said tubing is reciprocated; and means spaced on said eduction tubing for reversing the operation of said clutch means to eiiect travel of said frame 'structure back and forth between said spaced means.

l*5. 1n a well pumping apparatushaving 1a casing, an eduction tubing lin the casing and a reciprocatingpump near 'the lower end lof the tubing where- "1n the eduction tubing is caused, by action of the pump, to reciprocate relative to Vsaid casing, the improvement comprising .a device for 4cleaning perfor-ations in the casing including the com- `bination of: fa body adapted 'to beslidafbly lpositioned upon :a .string of eduction tubing for intro-duction therewith into a well, there being stops -on said eduction tubing to limit Asliding .movement of said body.; cleaning ngers carried by the body .for cleaning the casing rperforations and -aiordin'g a frictional drag :tending `to prevent movement of said body relative to said casing and thereby to cause movement thereof relative to vsaid eduction tubing; clutch means vcarried by the body mterengaging .said body and eduction tubing -tduring lmovement of said tubing in one .direction :relative -to said casing `to force said body to move with said eduction tubing, :and disengaging said `body from said tubing yduring movement of said tubing in the opposite direction whereof said body tends Vto remain stationary in said casing but move relative to said eduction tubing thereof on repeated reciproca-tion of said tub-ing to progress the body :along `the tubing in cleaning engagement with the casing; `and La mechanism carried by said body and engageable with :the .stops on rsaid eduction tubing for automatically reversing the position ni said "clutch means `so as zto interengage ,said 'body and eduction tubing when said :eduction tubing Amoves in said opposite direction, and to disengage said body and eduction tubing when said :eduction tubing is moving invsaid one direction, thereby to cause progression of said body in the opposite direction.

6. A device for cleaning Well casing perforations, comprising: a, body adapted to be slidably mounted on a reciprocable string of well tubing and lowered therewith into a 'well casing, there being spaced stops on said well tubing to limit sliding movement of said body on said well tubing; cleaning fingers carried by the body for frictionally engaging and cleaning the casing perforations; a clutch member carried by said body and having a central opening to receive said well tubing, said clutch member being tiltable on said well tubing between a first and second extreme position, whereby in the first position of said clutch member, the margins of said opening tend to grip the well tubing on downward movement of the well tubing relative to the clutch member and to slide on the weil tubing on upward movement of the well tubing relative to the clutch member, and whereby in the second position of said clutch member the margins of said opening tend to grip the well tubing on upward movement of the well tubing relative to the clutch member and to slide on the well tubing on downward movement of the well tubing relative to the clutch member; said clutch member thus tending, when in its first position, to advance said body downwardly on said well tubing, and when in its second position, to advance said body upwardly on said well tubing; and a clutch shifting means mounted on said body and cooperating with the stops on said 10 well tubing to shift said clutch member between its rst and second positions, thereby to cause said body member to progress alternately, downwardly and upwardly on said well tubing.

7. A device for cleaning casing perforations comprising in combination: a body mountable upon a reciprocable string of well tubing for introduction therewith into a well casing; fingers carried by the body for brushing and frictionally dragging on the interior of the casing to cleai` obstructions from perforations therein; a tilting clutch member carried by said body and engageable with said tubing, said clutch member being movable between a rst position permitting upward movement only of said body member relative to said tubing and a second position permitting downward movement only of said body member relative to said tubing; stops positioned at predetermined points along the length of the string of tubing; and an operating mechanism carried by said body and engageable with said stops to move said clutch member between its rst and second positions.

CARL J. McCOY.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 1,380,517 Bashara June 7, 1921 1,758,995 Armstrong et a1. May 20, 1930 1,844,760 Haynes Feb. 9, 1932 2,295,058 Smethers Sept. 8, 1942 2,421,434 Reistle et al June 3, 1947

Patent Citations
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US1758995 *May 18, 1928May 20, 1930Armstrong John CTubing cleaner and protector
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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2959224 *Sep 30, 1957Nov 8, 1960Houston Oil Field Mat Co IncWell hole cleaner and method
US5135051 *Jun 17, 1991Aug 4, 1992Facteau David MPerforation cleaning tool
US5893383 *Nov 25, 1997Apr 13, 1999Perfclean InternationalFluidic Oscillator
US6029746 *Jul 22, 1997Feb 29, 2000Vortech, Inc.Self-excited jet stimulation tool for cleaning and stimulating wells
US6470980Oct 3, 2000Oct 29, 2002Rex A. DoddSelf-excited drill bit sub
US7007865Aug 14, 2003Mar 7, 2006Rex A. DoddSelf-adjusting nozzle
Classifications
U.S. Classification166/105, 166/171
International ClassificationE21B37/00, E21B37/08
Cooperative ClassificationE21B37/08
European ClassificationE21B37/08