US2315069A - Scraper - Google Patents

Description

March 30,1943.

J. H. VYMGKEAN Er AL/ SCRAPER Filed April 17, 1940 Patented Mar. 30, 1943 scRArER o John H. McKean-and verett K. McKean, Alvin, Tex., asslgnors to Stanolind Oil and Gas Com-y i pany, Tulsa, Okla., a corporation oi Delaware application Apri1.17,.194o, .serial Nassopsr 4 claims.' (ci. les-1s) This invention relates to scrapers designed to remove .deposits from the interiors ,oitubea pipes l and the like. More particularly it relates to Scrapersl :for the removalof deposits from wells and still more particularly to Scrapers for the removal oi parafiln and similar deposits -from the tubings of oil wells.

In many different connections deposits are Ibuilt up on the interiors of tubings and similar .conduits and it is often desired to remove these deposits. One particularly serious problem of this type exists in oil wells producing certain types of fluids notably crude oil containing large amounts oiv wax. As such fluids progress up the tubing of a l well the pressure'drops with the result that some of the 'lighter hydrocarbons are vaporized. 'At the same time the temperature is lowered with the result that waxy materials, commonly known as lparalmand sometimes other materials of an asphaltic or resinous naturev are thrownout and deposited on the walls of the tubing, particularly in the upper sections thereof. These deposits frequently reach such proportions that the capacity of the well is seriously reduced and in fact the well may completely plug. It has therefore long `been the custom in connection with Iwells of this sort to remove these deposits by various. means including the use of solvents and the running ci scrapers.

In general the use of solvents for the removal of these deposits has not .been found very satisfac-l tory and, on the other hand, the use o-f scrapers has ybeen found time-consuming and expensivel due to the unsatisfactory devices heretofore used. In general the prior art Scrapers have `not been successful in completely and expeditiously removing difcult deposits in a single run. u This is due in large measure to the fact that these devices have served only to 'cut grooves or svvaths4 through the parailin without completely' removing it and much difficulty/ has been encountered due tothe balling up of the para-illu above the cutting knives or similar elementsused in the prior art Scrapers.

It is anobject of our invention to provide new and improved Scrapers for refmdving deposits from tubes and the like. More particularly it is an object of our invention to provide aA superior scraper 'for removing deposits from wells and par-v ticularly for removing deposits, such as .parailin from the tubing oi' 'oil wells. A

A more particular object of our lnvention'is to provide a scraper oi the type -mentionedwhich will completely remove the deposits.l Another particular object of' our invention is to fprovide a scraper which will not cause hailing up oi' the Also the use oi wire cutting elements ma deposit ahead-of the cutting elements and which will, on the otherhand, cut thel deposits completely-free from the tubing and result in their complete removal from the well. a

It is also an object of o ur invention to provide a scraper of the type indicated which has unusual 'structural strength. .Another .object of our invention is to provide a scraper having cutting elements which will not be interfered withby the presence of obstructions in thetubing but which willpass by such obstructions and, after passing them, return. to the normal cutting position. w

A further object of our invention 'is to provide ascraper which -will give minimum interference with the now of uuid, v

Other and moreV detailed objects, advantages' and uses of our invention will become apparent as the description thereof proceeds.

. In general we accomplish these objectives by the use of wires as cutting elements and the wires are preferably constructed and arranged so that they will spring past obstructions and'then return to their normal cutting positions. The use' of wi-res is highly advantageous as compared with Y the use of .cutting knives or similar. cutting elements which present large surfaces to the deposit, since the wires reduce the pullnecessary to operate the scraper, thus eliminating the rbreakage of scraping tools,'and do not cause balling of the par'ain'ahead of the cutting elements. ttes it of using possible to` do away -with the necessity separate :spring members for the cutting ele-n ments', since the cutting element and spring can be made from a single piece of wire. Furthermore, the wire cutters can be so shaped and of suciisize and spacing as to give a scraping action over the complete Isurface oi the tubing without.

4putting any undue strain on the scraper.

Our invention will now be further described in connection wt'ih the accompanying drawing whichv shows one preferred embodiment therecfand` in Figure la is an elevation partly in section ofv the upper portion of a scraper in accordance with our invention;

Figure 1b is an elevation partly in section of the lower end oi this same scraper. the upper end' of' Figure 1b corresponding to the lower end of Figure la; 1 s

.Figures 2 and 3 are front and side elevations,

respectively, of one of the cutting elements shown;

in the device of Figures Ia and 1b;`

. Figurevfiis a'diagram illustrating one possiblev the form used by and also through holes 2 e arrangement voi'cutting lelements in the deviceof Figures la and 1b; i 1

Figure 5'is a detail in. elevation showing one of the-- cutting elements in cutting position; and

Figure 6 is a detail in elevation showing one of lthe cutting elements in depressedl position, as

when passing 'an obstruction. Our scraping tool as shown is made in three sections. The top section 2|, in the form in which we has constructed it, is about 6 inches long. It is hollow and threaded at its lower end f and through the hollow interior 25'of the. upper section and is knotted below it. a This knot 23 is then drawn up into the upper section2| where it comes to rest against shoulder 26. 'Iihe central section 24 is then screwed onto the upper section 2| and the device is thus -aillxed to the wire line 28 and is ready to runin the conventional mannel'.

The middle section 24 is a steel shaft which, in us,'is about 4 feet long. 'I'he principal purpose of-this section is to give the tool weight which is of advantage in spudding cover the complete internal circumference of the tubing. Thel length of the cutting elements is preferably such as to give about 11g inch clearance with the internal walls of the tubing when the cutting element is standing straight outwardly.

As seen in Figure 1b the lower end 4| of our cutting tool is preferably tapered to assist in the insertion of the tool into the parailined tubing.

It is preferableto arrange the cutting elements in opposed pairs so as to avoid any tendency for the cutting action to give unbalanced forces. Thus in the form shown in Figure 1b the two' lowermost cutters are arranged 180 apart, making one of the opposed pairs.

Figure 4 illustrates diagrammatically one arrangement of these cutting elements. 'Ihe 10W- ermost cutting element is numbered I and the next'higher` one is numbered 2 and so on to the uppermost one .which is numbered I6. The

' positions of the arrows in Figure 4 shows the. cirit into the hole through the'parafilned section of the tubing. Obviously if the tool is otherwise sufficiently heavy this section can be omitted and it is alsopossible, of course, to use .a weighted section below rather than above the cutting section.

At the lower end or the central threaded joint tions 2|- and 24, l attached to the lower or cutting section 3|.

Near its upper end section '3| carries a ilat portion 32 which can be used ,in handling this section, for instance, by a wrench or the like.

The cutters 33 carried by this bottom section 3| are outline cutters and are made of tempered spring steel wire. `These cutters are placed in keyways 34 and are keyedin place by pins 35 section 24 is a.

30, similar to that between sec-l by whichthis central section is cumferential spacing of these numbered cutters. l

Thus, the third cutting element from the bottom is spaced 221/2 from the rst, the fth is spaced 221A.; from the third, etc. Figure 1b shows only two of the eight opposed pairs of cutting elements, these pairs being made up of the rst and second and ninth and tenth cutting elements denoted 331, 332, 33 and 331 respectively. Thus the cutting elements are spaced both longitudinally' and circumferentially so as to give complete coverage, great structural strength, and balanced forces.

From the preceding description of our device its operation will largely be apparent.. The device is dropped into a Well on wire line 28 through the para'ined section of the tubing, the cutters 33 being forced into the position shown in Figure 1b by contact with the deposit. When the tool has passed below the parafiined section of the tubing, the cutting elements 33 will fall outwardl ly until heels 39 encounter the bases of keyways passing through holes in the walls of the keyways 33 (Figure 3) inthe cutting elements 33. It will be noted that the key- Ways do not pass completely through the body of the tool as in some prior art devices .and we thus obtain improved structural strength.

As seen in Figures 2 and 3, each' of the cutters 33 are preferably shaped from a single piece 'of wire which is bent to give' a dat outline cutting head 31 and to form an opening or loop. adjacent the cutting edge of the cutter, -a spring section 33 (defining aperture 33) and a short projecting heel 39. The angle portion 31 of cutter and the heel 33 is preferably about 90 or slightly more, depending in part on the shape of the back wallot keyways 34 against which heels 33 rest. In the form which we have l used, the diameter of the tool shaft in alll three inch andthe width of the outline 1/2 inch, the cutters if inch tempered are used in such numas to cut through the between the outline head around the m- 34 at which point the cutter heads 31 will stand horizontally or preferably pointed upwardly at a slight angle as shown in Figure 5. `If gravity should not cause thevcutting elements to assume e this position, they will assume it when their leo upper and outer edges encounter the surface of the paraffin as the tool is pulled upward since it will be noted that the'se. upper and outer edges project beyond the keyways and are exposed to irictional contact with the paraln. 'I'he result is that during the upward course of the tool the outline cutters stand out and each one cuts away its section of the parailin 42 from the tubing 43 (Figure 5) thus making it possible for the upilouiring oil to disintegrate and remove the depos t.

tion 43 on tubing 43 (Figure 6) ,it springs down- Figure 6) untu the obstruction is passed, artrwhichthe spring action of the wire forces the cutter back to its cutting position (Figure 5).

Actual experience has shown Athat even in extremely badly paralned wells the cutting tooll or our invention permits the removal oi' the paramn far more completely and expeditiously than 'do the Scrapers heretofore used. The wire out ting elements not only give complete cutting but When a cutting element encounters an obstruc-l prevent balling and undue frictlonal resistance because the parailin, after having been cut away.

from the tubing,l can pass through the loop or opening in the cutter, as shown in Figures 5 and 6,'and consequently give minimum interference with the oil passing upwardly through the weil, which, in turn, assists in the removal of the paraln deposit.

1 Our scraper and modifications of it which will occur to 'those skilled inthe art can likewise be used in scraping oil pipe lines which `frequently contain parailinic or other deposits.

While we have described our invention in connection with a specific embodiment thereof, it is' to be understood that this is by way of illustration and not lby way of limitation and that we do4 not mean to be restricted thereto except as indicated in `themzipended claims.

Weclaim: 1. A scraper for removing parailin deposits and the like from the interior of aconduit, comprising a body portion having a plurality of keyways', an outline cutter mounted in each of said keyways, each of said outline cutters comprising a 'T wire outline cutting head having a cutting edge formed as a loop and a portion Aadapted to hold said head yieldingly in cutting position.

2. A scraper according to claim 1 in which said outline cutters are separated longitudinally -from each other on saidbody portion and also placed circumferentially on said body portion to cover substantially the whole surface of the conduit to be scraped. y

3. A scraper for removing parailln deposits ann the like from the interior of a conduit, comprising a body portion havinga plurality of keyways, an outline cutterwrnounted in each of said keyways, each of said outline cutters comprising a.

wire outline cutting head having a cutting edge formed as a loop. a' spring portion integral therewith and a heel portion integral with said spring` portion adapted to cooperate with one of said'- keyways to hold said head yieldingly in cutting position. A

4. A scraper according to claim l in which said outline cutters are mounted in said keyways by means of pins passing through said spring portion.V

JOHN H. MCKEAN. K. MCKEAN. v

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