US2893494A - Paraffin cutter - Google Patents

Description

D. J. MCDUFFIE July 7, 1959 PARAFFIN CUTTER 2 Sheets-Sheet 1' am .1. Mc Duff/'e IN V EN TOR.

Filed March 11, 1957 July 7, 1959 D. J. MCDUFFIE 2,893,494

PARAFFIN CUTTER Filed March 1]., 1957 2 Sheets-Sheet 2 PARAFFIN CUTTER Duel J. McDulie, Plaquemne, La.

Application March 11, 1957, Serial No. 645,156

6 Claims. (Cl. 166-176)I This invention comprises a novel and useful improved paraliin cutter and more particularly relates to an apparatus and method for removing the paran deposits which customarily form in the ow lines and tubing of oil wells.

A very serious problem attending the pumping and owing of petroleum through a tubing or ow line of a flowing or pumped oil well is the deposition of paraiiin upon the internal walls of the tubing and ow lines as the paraiin condenses or precipitates out of the more volatile liquid oil during the passage of the latter through the tubing or flow line. As these parailin deposits build up upon the interior of the tubing or flow line, they restrict the cross sectional internal diameter of the latter to such an extent as to seriously hamper and in some instances entirely prohibit'the tlow of oil through the flow line or tubing; and in other instances seriously interfere with or prevent the operation of a pump and the pumping rods in the tubing. When this condition arises, it has been heretofore frequently necessary to pull the tubing or ow line from the well in order to remove the parain and restore the well vto production; or to resort to various more or less expensive operations for mechanically or chemically cleaning the parafn deposits from the same.

It is therefore a primary purpose of this invention to provide an apparatus and a method whereby such parat-lin deposits may be quickly land readily removed from the tubing or flow line to thereby restore the same to normal operation; and whereby this object may be readily and quickly effected in an improved manner.

A further object of the invention is to provide an apparatus and method which shall be eifective for removing paraiin deposits despite any quantities which may be present in or occur in the tubing or tlow line.

A still further object of this invention is to provide an apparatus and a method whereby a pump rod string or the like may be employed for moving the paran cutter through a ow line or tubing and whereby the resiliency of the cutter may accommodate the latter to inequalities in the internal diameter or surface of the tlow line or tubing and enhance the eiciency of operation of the device.

A still further important object of the invention is to provide a paraiiin cutter having a plurality of longitudinally spaced, substantially circular, resilient cutter blades thereon which will be of extremely simple and inexpensive construction `and yet highly efficient for the purpose intended.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

Figure 1 is a view'in vertical section showing a porrrite States Patent O ICC tion of a well bore having a ow line or tubing therein and showing a preferred embodiment of paraffin cutter in accordance with this invention operatively disposed therein for cleaning parailin from the interior of the tubme;

Figure 2 is a perspective view of the paratlin cutter of Figure 1;

Figures 3-5 are horizontal sectional views taken substantially upon the planes indicated by the section lines 3--3, 4--4 and 5 5, respectively, of Figure 2 and showing upon an enlarged scale the structural details and particular mounting of the individual cutters of the device;

Figure 6 is an elevational view of a second embodiment of a paraiiin cutter in accordance with this invention, but having a single, rigid, annular cutter blade thereon;

Figure 7 is a horizontal sectional view taken substantially upon the plane indicated by the section line 7 7 of Figure 6, but upon an enlarged scale:

Figure 8 is a fragmentary view similar to Figure 1 and illustrating a tirst step in the method of cleaning parailin from llow line or tubing in accordance with .this invention and in which the undersized, annular, rigid cutter glade is passed through the tubing to remove the major portion of the parailn deposits but that leaves a thin coating thereof on the internal Wall of the tubing;

Figure 9 is a view similar to Figure 8, but showing the manner in which a second rigid, annular cutter blade, lin accordance with Figure 6, of substantially the same diameter as the internal diameter of the tubing is passed through the latter to complete the removal of the paraffin therefrom by removing the thin coating left by the step of Figure 8;

Figure l0 is a view similar to Figure 8, but showing an alternative method wherein the second step is per#v formed by the annular, resilient cutter blade of the embodiment of Figures 1-5; and,

Figure l1 is a detail view in vertical section, taken substantially upon the plane indicated by the section line 11-11 of Figure 7 and upon an enlarged scale.

Referring first to the embodiment of Figures 1-5, it will be seen that the numeral 10 designates the casing of a producing well, which may be either a flowing well or a pumped well, and in which is disposed a pump tubing or ilow line 12. Indicated by the numeral 14 is the lower portion of a pump rod string or a tool string, to which is secured the parati-in cutting tool indicated generally by the numeral 16 of this invention,"

lt will be'understood that in the operation of removing paraii'in deposits from the interior of a ow line or extremity 22 whereby the same may be connected to the pump rod string 14 in any conventional manner or to a wire line.

Referring now especially to Figures 3-5, it will be seen that the arbor 1S has secured thereto a plurality of substantially annular or circular cutters, three being shown in Figure 2, and which are indicated generally( by the numerals 24, 26 and 28. Eachof the resilient cutters 24, 26 and 28 is of identical4 construction, these cutters differing from each other solely" Patented July 7, 1959 YEach" ofl the cutters comprises" a single resilient, butA stil'wire' comprising an intermediate arcuate portion 3Q whichf is concentric` toY the4 axis of the; arbor 18` and extendsV throughout' the major' portion of its' length, as,

for example, between the points 32 and 34, and is shown inFigurcs3-'5';l this intermediate portion extends through at least 270 of the circumference of the arbor. The' intermediate portion at the'points 32and 34 is provided With terminal portions` 36 and 38; which extend radially inwardly Ytowards the arbor 18. The junction ot" the terminal portions with lthe ends of'th'e intermediate portion tlzus providerounded radially outwardly projecting points 32`and 34. Each of the terminal portions is attached to the arbor 18`.I Thus, for eachofthe cutters 24, 26and 28'; there is provided a pairvr of longitudinally' spaced, diametricallyextending bores 40 and 42 which are closely adjacent to each other, but spaced slightly longitudinally of' the arbor and are disposedfperpendicul'arly with respect to each other, as shown'in Figures 35. The terminal portions 36 and 38 are provided with end portions 44 and'46, respectively, which'extend through these bores and-have iiattened extremities^48 and- 50. It will be observed by reference to Figure 3 that the terminal portionsv 36 and 38' overlap each other.

As so far described, it will thus be apparent that each ofthe cutter blades comprises a resilient annulus which extends entire about the arbor, the major portion of this annulus being at a constant radius from the center of thea'rbon-and there being a slightrecess between-the points 32 and 34=where the terminal portions 36 and 38 cross 'each other.

It* is intended. that the resilient cutter blades 24, 26

and 28'shall be of slightly greater diameter than that of' the:tubing or ilow line in which the same are to be utilized in order that the inherent resiliency of the material of the cutter blades willV resiliently place the intermediate portion' 30- thereof intol av scraping contact with the wall of thelflow line or' tubing. Inasmuch as themajor portion 30 of each blade is supported solely by the two resilient arms formed by the terminal portions 36 and 33, it is evident that the blade'is exibly supported upon thev arbor with a greater exibili-ty than could be obtained from a support'at both sides of the arbor, whereby a stiffer material can be employed for the cutter blade.

Itwill-be observed next by comparing Figures 3, 4 and 5 that successive blades 26 and 28 yhave their-sets of bores 40 and'42-and their sets of terminal portions 36, 38 and ends 44 and 46 spaced at slightly less than 90 circumferentially of the arbor. from those of the immediately adjacent cutter blade. This provides that the portion of the. internal wall' of the flow line'or tubing which is not scrapedL by the blade which lies between the points 32 and 340i oneV blade will be engaged by the intermediate pon tion of the other blades to thus comprise a complete overlapping action of the blades on the wall of the flow line or-tubing.

It will thus be understood that there has been provided a highly effective paran' cutter, which by virtue of `its unusual resiliency asr'to construction and mounting Will accommodateitselfto irregularities in the internal diameter of fiow lines'or tubing, will compensate for any out-of-round conditions therein, and can be inserted'in pipes-V having smaller diameters than that of the inter mediate portion V30.

Referring next to Figures 6 and' 7, there is disclosed' a modifed construction' ofparafn cutter,` which, in place of the resilient 'circular cutter of the embodiment Vof Figf ures 1-5, employs'a rigid circular blade thereon. embodiment the cutter,A includes` an arbor 60l which is externally threaded as at' '-621 at its .upper end for reception in a box 6'4 having a pin 66'adapted'to be secured In' thisto therend of a pump rod string or tool stringv such asthat indicated at 14 in the preceding embodiment.

At its lower end, the arbor 60 is provided with rigid radially extending arms 68 and an annular band 70 is secured thereto as by welding or the like. This band and also the arms 68 are provided with a depending annular knife edge 72 as willbelap'parent from Figure 11.

I' If desired, as shownin Figure 7, the arm 68 may extend slightly beyond theband 70, wlie'reby to space the latter slightly from the internal walls of a flow line or tubing.

Referring now to Figure 8, there is disclosed an embodiment: similar'to' that ofv Figures 6 and 7 and which embodiment is substantially identical with that of my prior Patent No. 2,521,076. This particular form of cutter is identical with that of Figures 6 and 7, except that the arbor thereof is integral with the diametrically enlarged upper portion 82 and which is adapted to be secured to the lower en'd'of the pump rod string or tool stingfp'reviously mentioned. As in the embodiment of Figures 6 and`7, the radially extending arms 86 and the annlar`rim'88, having a knife edge 90 thereon, are identical with the arms, rim and knife edge, 68, 70 and 72, of the'f preceding embodiment, However, in this form, thean'nu'lar' blade, instead of being welded to the arms 68, is secured'to the arbor as by nuts 92 carried by the diametrically'reduced, externally threaded portion 94.

The preferredmethod otcleaning paran from a ow line' or`tubing in accordance with this invention is as follows, reference' beingimade particularly to the views of'Figures` SL10; In=Figure 8, the flow line or tubing 12 is'shown with an internal deposition of paran in the form'of a coating or'lin'ingA 96. While ltheview indicates thefcoat'in'gas being substantially regular in its nature, it-is`to be understood'l that actually parain deposits are usually irregular iii-nature and may be of any magnitude up to'A substantially entirely bridging and closing the internaldiameter of-'the tubing.

Asv the iirst'step of this invention, there is secured to the end ofthe"strin'g 1'4 aA paraiin cutter in which the annular cutter blade'isof slightly less diameter than that of the interior ofthe tubing 12. Thus, when the cutter is passedthrough the tubing', it will remove the major potionof the'paran'deposit, but will leave a relatively thin lm or' coating; asat 9'8, which may be of the order ofiaboutone'tliirtyesecondof an inch in thickness. The purpose of-itlis'is topermitfthe use of a relatively heavy and rigid cutter forv removing the major portion of the parain; and inforder to'permit the use of the rigid cutter, the same-'must be of alessdiameter than the wall of a boil-e` in orderto' permit the device to be passed through atubinglwhielimaybeout-of-round or have other surface-irregularitiestherein which would prevent the passageofj al cutter having a close' t with the wall of the tubing.

Illustrated infFigure 8 isthat form of paraiim cutter' shownlandclaimed in my above mentioned priorpatent. Itwill b'eunderstoo'd,- however, that the same may be, in' some instances, ofi the form shown in Figuresl 6 and 7, whilelinfurther"A instances satisfactory results may be obtained by use of the cutter of Figures l-5.

VAfter"y the'undersized cuttery has been run through the pipe,fas in Figure 8, the same is removed and to the striugflfis attached-a second cutter. such as that shown inrF-igu'res 61and7; Thev secondcutter, however, is of sul'istantiallycthesameI internaldiameter as the tubing 12, as indicated in Figure 9, is employed to scrape away the'V remainder'y of the r paraffin constituted byy the thin coating of 'sheaff98- left by theiirst cutter.

Alternatively,1asshown in Figure l0, in place of thc rigidcutter shown-'inFigure 9, the second step of the method may; be performed by thev resilient cutter of lr'igures l--S.. As` the latter is passedthrough the tubing` 12, its resilient annular cutter elements 24, 26 and 28-willl remove the lmror coating 98. DuringthisV opera tion," that portion of this thin lm, as at 100, which may have passed or been left by the opening between the points 32 and 34 of one of the annular resilient cutter blades, as shown in Figure l0, will be removed completely by succeeding blades.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

1. A paraffin cutter for oil well tubing comprising an arbor, means for connecting said arbor to a means for vertical reciprocation in said tubing, a plurality of resilient cutters secured to said arbor in longitudinally spaced position thereon, said arbor having a pair of substantially perpendicular, diametrically spaced bores for each cutter, each cutter comprising a separate substantially circular wire having a single convolution about said arbor and having a pair of ends secured in said pair of bores.

2. The combination of claim 1 wherein successive pair of bores are disposed at successive angular intervals to each other circumferentially of said arbor.

3. The combination of claim 1 wherein each cutter has its end portions overlapping each other and in spaced relation longitudinally of said arbor.

4. The combination of claim 1 wherein each cutter has an intermediate circular portion surrounding the major portion of the circumference of the arbor and radially inwardly directed terminal portions, the terminal portions overlapping and having their ends extending through and secured in said pair of bores.

5. The combination of claim l wherein each cutter has an intermediate circular portion surrounding the major portion of the circumference of the arbor and radially inwardly directed terminal portions, the terminal portions overlapping and having their ends extending through and secured in said pair of bores, the junction of the intermediate portion with the terminal portions providing a pair of rounded, radially outwardly projecting points.

6. The combination of claim 1 wherein each cutter has an intermediate circular portion surrounding the major portion of the circumference of the arbor and radially inwardly directed terminal portions, the terminal portions overlapping and having their ends extending through and secured in said pair of bores, each cutter projecting from one terminal portion both circumferentially and longitudinally of the arbor to its other terminal portion.

References Cited in the le of this patent UNITED STATES PATENTS 2,322,419 Cranford June 22, 1943 2,433,955 Meynig Ian. 6, 1948 2,690,808 Besse Oct. 5, 1954

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