US3330358A - Valved migratory scraper - Google Patents

Description

J v m k 2 4 .wo m I I I I l IIH II IHHII I- 6 M WARREN F. WARD ATTORNEYJ July 11, 1967 w. F. WARD VALVE-D MIGRATORY SCRAPER Filed Feb. 26, 1965 United States Patent 3,330,358 ALVED DIIGRATORY SCRAPER Warren F. Ward, 4419 Rawling St., Dallas, Tex. 75219 Filed Feb. 26, 1965, Ser. No. 435,551 11 Claims. (Cl. 166-175) ABSTRACT OF THE DISCLOSURE A paraffin scraper designed to migrate up and down a length of sucker rod to clean the same and also the tubing in which the rod is reciprocating, the scraper having a body surrounding the rod and insertable thereon by way of a slot disposed longitudinally straight through the body, and the scraper having a valve insertable into the lower end of the slot and carried upon a slender actuator which is longer than the body, passes loosely through the slot and keeps the valve located with respect to the slot, the valve and actuator having means surrounding the sucker rod above and below the body to guide them thereon and to move the valve into and out of the slot in response to impact against abutments on the sucker rod, thereby reversing the direction of migration of the scraper on the sucker rod.

This invention relates to self-cleaning oil well paraffin scrapers of the type which surround a sucker rod and migrate up and down substantially the entire length thereof as the well is pumped, and more particulirly the invention relates to the improvement of paraflin scrapers by providing novel valve means operated upon contact with the sucker rod upsets to cause the scraper to rise when it reaches the bottom upset of the sucker rod and to fall when it reaches the top upset.

It is a principal object of this invention to provide a parafiin scraper capable of migrating up and down a lengt of sucker rod as it reciprocates in a well for the purpose of cleaning paraffin deposits not only from the rod but also from the adjacent tubing, the direction of migration of the scraper being selectively determined by automatically-operated valve means cooperating with the downward effect of gravity and with the upward effect of the rising column of fluid in the tubing.

Another important object of the invention is to provide a novel paralfin scraper combination including a scraper of the type shown generally in Patents 2,604,364 and 2,793,917 and characterized by a body with a longitudinal slot through its side Wall communicating with a central bore loosely receiving the sucker rod, and the present novel combination further including a valve for selective- 1y opening and closing the slot to alter the resistance of the scraper body to the upward flow of fluid therepast, whereby when the valve is closed the scraper body will present a large resistance to fluid flow causing it to rise in the tubing, and when the valve is open the body will present a much smaller resistance to flow therepast thereby permitting the force of gravity to cause it to descend in the tubing.

A further important object of the invention is to provide a combined scraper body and valve with means for automatically and selectively opening or closing the valve when the scraper reaches one end or the other of the sucker rod, such means including a trip mechanism passing through the slot in the body and extending longitudinally beyond the body in both directions, so that when the body approaches a sucker rod upset, the trip mechanism will contact the latter and will be shifted longitudinally of the body to change the position of the valve with respect to the slot, and thereby reverse the direction of migration.

Since the valved scraper depends upon gravity to cause it to drop downwardly along the sucker rod when the valve is opened, it is important that the scraper be heavy enough to drop despite the upwardly flowing column of pumped fluid. It is also important that the opening provided by the longitudinal slot in the scraper body be large enough to by-pass the fluid to make it possible for the scraper to drop. The scraper body can be made of metal, rubber, or plastic, such as nylon, although in the latter case it may be necessary to add weight to the nylon body. The outside diameter of the body should be somewhat less than the tubing, and the bore through the body should be somewhat greater in diameter than the sucker rod. Experiments on working models have shown that a body having a central bore works well on a diameter sucker rod. The width of the longitudinal slot should be great enough not only to by-pass the well fluid flow, but also great enough to permit the insertion of the sucker rod into the bore through the slot by forcing it therethrough with a snapping action.

Experiments have shown that the valve member works well if it is made of rubber and used with a nylon or metal scraper body, and alternatively that a nylon valve member works well with a rubber body. The valve member should be an accurate fit in the slot without being tight enough to wedge therein, it being unnecessary that a perfect seal be formed when the valve member is inserted in the slot. A small detent may be added to yieldably hold the valve member in the slot, although the upward fluid flow will usually be adequate to accomplish this purpose.

The edges of the body member serve to scrape both the sucker rod and the tubing as the body member travels up and down therewithin. Moreover, there are several phenomena which contribute to rapid rotation of the body during its travel, including the usual circular swirl of the fluid rising within the tubing, as well as the tendency of the valve member itself to lie near one side or the other of the slot when it is in open position, thereby causing deflection of the fluid passing through the slot which results in a circumferential component of force tending to cause rotary motion of the body. At any rate, the body not only travels in a longitudinal direction, it also rotates during this travel so that the edges of the slot act as paraifin cleaning blades slicing the soft parafiin both from the inner walls of the tubing and from the outer surface of the sucker rod. The actuator rod extending through the slot is a very loose fit therein and tends to lash about during migration to clean the sides of the slot of parafi'in deposits.

It is still another important object of the invention to provide a migratory, valved paraflin scraper which can be applied onto a standard sucker rod by merely snapping it into place, with the result that there is no need to provide a special sucker rod wherein one of the ends has no fixed upset structure so that a fully cylindrical scraper might be introduced over that end of the rod. The present structure can be snapped onto any standard rod without any alteration.

The known prior art includes Patent 2,720,925 which shows a cylindrical moving scraper structure which can be introduced over the end of a sucker rod to be actuated by rod-engaging dogs along the length thereof. The mode of operation and the structure thereof is, of course, different from the present invention. The prior art also includes various go-devils in the form of hollow torpedos which can be introduced into a pipeline, and some of which go-devils have valves which are manipulated by the striking of a stop located inside of the pipeline, but none of these devices would be operative within a tubing string which also has a sucker rod extending through its center. In general, the present structure operates most satisfactory in wells in which the tubing is relatively as straight so that the sucker rods tend to maintain a centered position within the tubing. However, in wells where the bore is not straight, the tendency of the sucker rod to lie against the tubing wall in an off-center position would tend to prevent free longitudinal movement of the present scraper body. This condition can be corrected in a satisfactory manner by mounting a fixed scraper on each end of the sucker rod, such as a scraper of the type shown in Patents 2,604,364; 2,793,917 or others, these scrapers serving the purpose of holding the sucker rod centered with respect to the tubing wall. Obviously, the present migratory scraper can operate between two fixed scrapers or between any other abutments which remain fixed to the sucker rod. Therefore, the operation of this migratory scraper is not limited to abutting against the upset at each end of the rod.

The present disclosure also includes novel specific structures for illustrating several practical embodiments of the present invention, these embodiments being described hereinafter in greater detail.

Other objects and advantages of the present invention will become apparent during the following discussion of the drawing, wherein:

FIG. 1 is a view in perspective showing a valved scraper according to the present invention descending on a sucker rod located within a pump-tubing string, the tubing being broken away to show the scraper assembly approaching the upset at the lower end of the illustrated rod;

FIG. 2 is an elevation view of the structure shown in FIG. 1, but showing the scraper after it has contacted the upset and closed the valve structure, thereby causing the scraper to rise within the tubing string;

FIG. 3 is an elevation view similar to FIG. 2, but taken at a location near the upper end of the sucker rod and showing the valved scraper assembly abutted against the upper upset of the sucker rod, with the result that the valve member has been moved to an open position, thereby adjusting the scraper assembly to commence its descent;

FIG. 4 is a view of a valve actuating rod member;

FIG. 5 is a perspective view of one satisfactory form of valve member constructed of a suitable plastic;

FIG. 6 is a perspective view of a modified valve member similar in external shape to the valve member shown in FIG. .5, but comprising a rubber or neoprene member into which a metal insert has been molded; and

FIG. 7 is a perspective view of the metal insert employed in the modified form of valve member shown in FIG. 6.

Referring now to the drawings, FIG, 1 shows a sucker rod R disposed within a length of pump tubing T, the latter being shown in cross-section so as to illustrate a migratory paraflin scraper assembly according to the present invention located within the tubing. FIGS. 1, 2, and 3 shows the parafiin scraper assembly in progressively different positions, as will be described hereinafter. The sucker rod R is'a standard rod having an upset U at each end located adjacent wrench flats W which are in turn located near threaded end portions, all of usual design.

The scraper assembly includes a scraper body 1 of a design which is generally well-known in the prior art and is characterized by a substantially cylindrical body having a bore 1a through the center thereof. Since it is necessary that the body slide up and down on the sucker rod, the

. diameter of the bore 1a is made somewhat greater than the diameter of the sucker rod R between the upsets U. Likewise, the outside diameter of the body 1 is made less than the inside diameter of the tubing T so as to permit the body to freely migrate within the tubing, and the ends of the body are chamfered as at 1b to prevent the body from snagging upon irregularities in the tubing. The body 1 also has a longitudinal slot 1c extending through its side wall, the slot being only slightly narrower in width than the diameter of the sucker rod R in the illustrated embodiment, whereby the rod can be forced through the slot and entered into the bore 1a with a snapping action. The slot 1c really need not be narrower than the rod in order to provide a workable assembly.

The migratory scraper assembly according to the present invention includes, in combination with the above described scraper body, valve means for selectively opening or blocking the longitudinal passageway provided by the slot 1c. This valve means comprises a valve member 2 and an actuating rod member 3 shown in detail in FIGS. 4 and 5. The valve member 2 comprises a C-shaped annular portion 2a having a slot 2b providing a gap sufficient to permit snapping the sucker rod R into the central bore 2c which bore in the relaxed condition is of somewhat larger diameter than the diameter of the sucker rod R so that it will be a free-sliding fit thereon. The annular portion 2a has an upwardly extending plug portion 2d of width sufiicient to slide freely into the slot 10 and sub stantially close the latter. The plug portion 2d has an inner surface 2e shaped to conform with a continuation of the surface of the bore 20. The plug portion is also narrowed at its upper end 2] to assist it to slide into the slot 10. When the plug is located in this slot in the position shown in FIG. 2, its outer surface in the vicinity of the reference character 2g substantially conforms with the chamfered outer surface 1b of the body 1.

The actuating rod member 3 has a threaded lower end 3a and a ring-shaped upper end 317, which does not close and therefore provides a gap through which the sucker rod R can be passed so as to place the ring-shaped portion 311 around the rod R as shown in FIGS. 1, 2, and 3. Assuming that the valve member 2 is made of nylon or some other dimensionally stable material, it is provided with a longitudinally threaded bore 2h into which the threaded portion 3a of the actuating member can be screwed. The valve member 2 also has a transverse bore 2k which is filled with a resilient rubber rod 4, the ends of which extend slightly out beyond the ends of the bore 2k so as to provide a small frictional grip sufficient to hold the valve member 2 in the slot 16 to prevent the force of gravity from causing the valve member 2 to drop from the position shown in FIG. 2 to the position shown in FIG. 3.

When the member 3 is screwed into the threaded bore 2h, the valve member 2 can be snapped onto the rod,

enough to permit it to be threaded. For example the valve member 5 can be made of rubber or neoprene, and in this event it will be provided with a C-shaped metal base ring 6 embedded in the rubber of the annular portion 5a. The rubber member 5 has a bore 5b extending through its plug portion 5d and aligning with a threaded bore 6b in the base ring 6 at a registering location. When a resilient valve means 5 is used in the present assembly, the actuating rod member 3 will have its threaded end 3a passed through the bore 5b and screwed into the bore 6b. If desired, small protrusions 52 can be molded on either side of the plug portion of the valve member 5 to serve the same frictional-grip purpose as the rubber detent rod 4, FIG. 5. The actuating rod 3 and the base ring 6' should be made of sturdy corrosion resistant materials, of which stainless steel is an example.

Referring now to FIGS. 1, 2, and 3, these three figures show a sequence of events occurring during normal operation of the present migratory scraper assembly. In

,FIG. 1, the scraper body 1 is descending toward the upset U at the lower end of the suckerrod R against the flow of fluid travelling in the direction of the arrows F. The valve member 2 is in open position so that the fluid is free to travel upwardly through the slot -1c to,

relieve enough pressure to permit the assembly to gravitate downwardly. As the assembly drops, eventually the annular portion 2a of the valve means will bottom against the upset U and the body 1 will settle downwardly on the plug portion 2d of the valve member, thereby driving the plug portion 2d into the slot 1c to assume the position shown in FIG. 2. The fluid passageway through the slot is thus closed by the valve member 2, thereby greatly increasing the resistance of the scraper body to the flow of fluid therepast in the direction of the arrow F, with the result that the whole scraper assembly becomes a piston which is buoyed up by the rising fluid F and forced to migrate upwardly on the sucker rod R, thereby scraping paraflin from the outer surface thereof.

Eventually, the wire loop 3b of the actuating member 3 bottoms upon the upset U at the upper end of the sucker rod R, and upon further upward advance by the body 1, the valve member 2 is dislodged from the slot 10, thereby reopening the slot to by-pass the fluid F therethrough and again reduce the buoyancy of the body 1 sufliciently so that the force of gravity can cause it to drop through the rising fluid F. The assembly will continue to drop until it reaches the position shown in FIG. 1, at which time the valve member will be closed again by re-insertin-g the plug portion 2d into the slot 10.

As is well-known to those skilled in the art, the fluid within the tubing T rotates during the pumping operation, and this has a tendency to rotate the body 1 and the membets 2 and 3 so as to increase the parafiin scraping efficiency by making the inside and outside edges of the slot is function as paraflin scraping edges thereby improving the cleaning action of the body both upon the sucker rod R and on the inner surfaces of the tubing T.

There is another factor contributing toward the rotation of the body 1 and the valve member 2 as the scraper assembly migrates. It will be noted in FIGS. 1 and 3 that when the valve member 2 is out of the slot 1c it usually does not hang directly below the slot, but is circumferentially ofiset usually one way or the other from one side of the plug portion 2d than from its other side, thereby admitting an eccentric rotative force component. The structure of the body might also be modified to advantage by having the slot skewed slightly so that it is no longer parallel with the axis of the bore 1a, thereby adding a further rotative component.

The present invention is not to be limited to the exact forms shown in the drawing, for obviously changes may be made therein within the scope of the following claims.

I claim:

1. In oil well equipment, a paraflin scraper assembly for migrating up and down on a sucker rod within a surro unding tubing string, comprising:

(a) a scraper body freely slidable within said tubing string, the body substantially surrounding the rod and having a longitudinal bore therethrough sized to freely pass the sucker rod, and the body having a straight slot in its side wall extending the full length of the body, the width of the slot approximating the diameter of the rod; and

(b) slot closing means comprising an actuating member slender in comparison with the cross-section of the slot and disposed longitudinally through the slot and extending therebeyond at its upper and low r ends, and having means fixed to said lower end including a valve member shaped to enter and close the slot when said closing means is raised with respect to the body to block the flow of fluid therethrough, and having means at said upper end to prevent downward withdrawal of the actuating memher from the slot, the latter means being longitudinally spaced from the plug by a distance greater than the length of the body.

2. In oil well equipment, a paraifin scraper assembly for migrating up and down on a sucker rod having upsets 6 at both ends and located within a surrounding tubing string, comprising:

(a) a scraper body freely slidable within said tubing string, the body substantially surrounding the rod and having a longitudinal bore therethrough sized to freely pass the sucker rod, and the body having a straight slot in its side wall extending the full length of the body, the width of the slot approximating the diameter of the rod; and

(b) slot closing means comprising an actuating member slender in comparison with the cross-section of the slot and extending longitudinally through the slot and therebeyond, and having slot plugging means located adjacent the lower end of the actuating member and including a portion shaped to fit snugly within the slot when introduced thereinto to restrict the flow of fluid therethrough, and having means at both ends of the actuating member to abut said upsets and shift the actuating member with respect to the body, the latter means being longitudinally spaced apart by a distance greater than the length of the body.

3. In oil well equipment, a paraflin scraper assembly for migrating up and down on a jointed sucker rod within a surrounding tubing string, comprising:

(a) a scraper body within the tubing string and substantially surrounding the sucker rod and sized to be freely slidable longitudinally of both, the body having longitudinal passageway means extending straight through its wall for conducting well fluids from one end of the body to the other;

(b) actuator means extending freely through said passageway means, the actuator means being slender in comparison with the cross-section of the passageway means and having means near each end spaced further apart than the length of the body and normally preventing withdrawal of the actuator means from the passageway means; and

(c) passageway-plugging means fixed to the actuator means and shaped to enter and close the passageway means when urged theretoward to restrict the flow of fluid therethrough, the plugging means being longitudinally shifted with respect to the passageway means when an end of the actuator means abuts a sucker rod joint.

4. In oil well equipment, a paraflin scraper assembly for migrating up and down on a jointed sucker rod within a surrounding tubing string, comprising:

(a) a scraper body Within the tubing string and substantially surrounding the sucker rod and sized to be freely slidable longitudinally of both, the body having longitudinal passageway means extending straight through its wall for conducting well fluids from one end of the body to the other;

(b) actuator means extending freely through said passageway means, the actuator means being slender in comparison with the cross-section of the passageway means and having loop means at least partly surrounding the sucker rod near each end of the body, the loop means being spaced further apart than the length of the body; and

(c) passageway-plugging means fixed to the actuator means and shaped to enter and close the passageway means when urged theretoward to restrict the flow of fluid therethrough, the plugging means being longitudinally shifted with respect to the passageway means when a loop means encounters a sucker rod joint.

5. In oil well equipment, a migratory paraflin scraper assembly for scraping both the surface of a sucker rod having upset ends and the walls of a surrounding tubing string, comprising:

(a) a scraper body of diameter less than the inside diameter of the tubing and having a longitudinal bore therethrough of greater diameter than the sucker rod diameter between the upset ends, and having a longitudinal slot extending straight through the side of the body and communicating with said bore, the

7 width of the slot approximating said diameter of the sucker rod;

(b) valve actuating means comprising the actuating rod which is slender with respect to the cross-section of the slot, saidrod extending longitudinally through the slot and having a portion bent loosely around the rod beyond one end of the body; and

(c) slot-plugging valve means fixed to the other end of the actuating rod and shaped to enter the slot to restrict the flow of fluid therethrough when the actuating means is longitudinally positioned to bring the valve means into the slot, the spacing between the valve means and the bent portion of the actuating rod being greater than the length of the body.

6. In an assembly as set forth in claim 5, said valve means comprising a plug portion shaped to enter the slot, and an annular portion attached thereto and at least partially surrounding the rod beyond the other end of the body.

7. In an assembly as set forth in claim 6, said valve means being attached to the actuating rod at the end of the plug portion located opposite said annular portion.

8. In an assembly as set forth in claim 7, said plug portion tapering toward a narrow point at the end where it joins the actuator rod.

9. In oil well equipment, a migratory parafiin scraper assembly for scraping both the surface of a sucker rod having upset ends and the walls of a surrounding tubing string, comprising:

(a) a substantially annular scraper body of diameter less than the inside diameter of the tubing and having a longitudinal bore therethrough of greater diameter than the sucker rod diameter between the upset ends, and having a longitudinal slot extending straight through the side of the body and communicating with said bore, the width of the slot approximating said diameter of the sucker rod;

(b) valve and valve-actuating means comprising a slender actuating member extending longitudinally through a slot and having C-shaped portions near its ends substantially surrounding the rod at opposite ends of the body, the C-shaped portions being spaced further apart than the length of the body; and having slot-plugging valve means fixed adjacent to the C- shaped portion at one end of the actuating means, and having a plug portion shaped to fit snugly within the slot to restrict the flow of fluid therethrough when the actuating means is longitudinally positioned to bring the plug portion into the slot.

10. In any assembly as set forth in claim 9, said plug portion having resilient detent means on its sides and located to be yieldably compressed when the plug means is entered in the slot.

11. In an assembly as set forth in claim 9, said plugging means comprising a rubber body having a metal insert embedded therein, and said actuating member comprising a metal rod threaded at one end and screwed into said insert.

References Cited UNITED STATES PATENTS 627,039 6/ 1899 Youmans 103-225 2,360,577 10/1944 Parrish 103225 2,604,364 7/1952 Ward 3084 2,655,113 10/1953 Ward 308-4 2,793,917 4/1957 Ward 3084 3,273,648 10/1966 Barnard 166175 CHARLES E. OCONNELL, Primary Examiner.

JAMES A. LEPPINK, Examiner.

Claims (1)

1. IN OIL WELL EQUIPMENT, A PARAFFIN SCRAPER ASSEMBLY FOR MIGRATING UP AND DOWN ON A SUCKER ROD WITHIN A SURROUNDING TUBING STRING, COMPRISING: (A) A SCRAPER BODY FREELY SLIDABLE WITHIN SAID TUBING STRING, THE BODY SUBSTANTIALLY SURROUNDING THE ROD AND HAVING A LONGITUDINAL BORE THERETHROUGH SIZED TO FREELY PASS THE SUCKER ROD, AND THE BODY HAVING A STRAIGHT SLOT IN ITS SIDE WALL EXTENDING THE FULL LENGTH OF THE BODY, THE WIDTH OF THE SLOT APPROXIMATING THE DIAMETER OF THE ROD; AND (B) SLOT CLOSING MEANS COMPRISING AN ACTUATING MEMBER SLENDER IN COMPARISON WITH THE CROSS-SECTION OF THE SLOT AND DISPOSED LONGITUDINALLY THROUGH THE SLOT AND EXTENDING THEREBEYOND AT ITS UPPER AND LOWER ENDS, AND HAVING MEANS FIXED TO SAID LOWER END INCLUDING A VALVE MEMBER SHAPED TO ENTER AND CLOSE THE SLOT WHEN SAID CLOSING MEANS IS RAISED WITH RESPECT TO THE BODY TO BLOCK THE FLOW OF FLUID THERETHROUGH, AND HAVING MEANS AT SAID UPPER END TO PREVENT DOWNWARD WITHDRAWAL OF THE ACTUATING MEMBER FROM THE SLOT, THE LATTER MEANS BEING LONGITUDINALLY SPACED FROM THE PLUG BY A DISTANCE GREATER THAN THE LENGTH OF THE BODY.

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