US3027946A

US3027946A - Oil well tubing scrapers

Info

Publication number: US3027946A
Application number: US765484A
Authority: US
Inventors: Ernest J Paskevich; Douglas C Elves
Original assignee: Individual
Current assignee: Individual
Priority date: 1958-10-06
Filing date: 1958-10-06
Publication date: 1962-04-03
Anticipated expiration: 1979-04-03

Description

April 3, 1962 E. J. PASKEVICH ETAL 3,027,946

OIL WELL TUBING SCRAPERS Filed Oct. 6, 1958 I B W ATTORNEY United States Canada 7 Filed Oct. 6, 1958, Ser. No. 765,484 1 Claim. (Cl. 166176) This invention relates to oil well tubing scrapers.

In the operation of oil well pumping equipment, it is common practice to provide scrapers on the sucker rods and to impart rotation to the polish rod and the attached sucker rods to scrape off parafiin and the like which may accumulate in the oil well tubing.

It is an object of this invention to provide an oil well tubing scraper, which does not require rotation of the sucker rods for effective operation, which can be applied to the sucker rods in a simple and more satisfactory manner, which does not impede flow of oil past its surfaces, which can be readily removed when required, and which remains in proper relation to the sucker rods during operation of the pump.

The invention will be described with reference to the accompanying drawing, in which FIGURE 1 is a side elevation of a scraper in accordance with the invention as applied to a sucker rod, and

FIGURE 2 is a sectional view on line 2-2 of FIG- URE 1.

In the drawing, 1 is a conventional sucker rod of oil well pumping equipment and 2 thEQll well tubing. The scraper in accordance with the invention is indicated at 3 and comprises as shown, an integral length wire 4 formed of spring steel or other metal and having a plurality of deformed portions 5 at each end thereof. Each deformed portion 5 is of arcuate form to describe an are about the longitudinal axis of the scraper, such axis coinciding with the longitudinal axis of the sucker rod. Each deformed portion 5 extends through an arc in excess of 90 with alternate portions 5 being disposed on opposite sides of such longitudinal axis. Each deformed portion 5 comprises a terminal section 511 having partial loops 5b extending therefrom, each partial loop 5b of one portion 5 being a continuation of a partial loop 5b of the adjacent portion 5 to form a partial convolution extending from one to the adjacent one of the terminal sections 511. The described are has a radius approximately equal to that of the sucker rod whereby, when the scraper is applied to the rod, the portions 5 will engage the rod and wrap around the same in excess of 180 of surface contact.

The partial convolutions formed by the loops 5b at one end of the wire length lie on one side of the longitudinal axis of the scraper, i.e., they are engageable with the surface of the sucker rod on one side of the axis thereof, whereas the partial convolutions formed by the loops 5b at the other end of the wire length lie on the other or opposite side of the longitudinal axis of the scraper, i.e., they are engageable with the surface of the sucker rod on the other or opposite side of the axis thereof. Thus, the wire length may be clipped upon the sucker rod and, due to the spring tension of the end portions, cannot become detached therefrom except under extreme lateral pressure.

Intermediate the end portions of the wire length and substantially midway between the ends thereof is a scraping portion 6 which is of spiral or helical form, the outer cylindrical diameter of which is considerably greater than that of the sucker rod and but slightly less than the internal diameter of the tubing 2. The helical portion 6 may comprise a single convolution of a helix, as shown, or a plurality of convolutions. It will thus be apparent that the helical portion 6 will traverse the entire circumferential extent of the interior wall of the tubing 2.

- s,s27,a46 Patented Apr- 1962 The wire from which the scraper is formed may be approximately in diameter and its cross section may be round, square or of other suitable shape. Preferably, the wire is heat treated to provide desirable mechanical properties including optimum hardness and resilience.

While dimensions of the scraper may vary, the follow ing are given by way of example:

Inches Length 17 Outer diameter of spiral portion 6 2% As shown, each deformed portion 5 describes an arc of approximately 220-230".

It is proposed that scrapers as described will be placed on the sucker rods at intervals of approximately two feet, six inches whereby during the course of a pumping stroke the scrapers will overlap in their travel.

It will be apparent that, as the sucker rods reciprocate in the oil well tubing, the helical scraping portions 6 will scrape accumulated wax off the tubing wall. Thus, rotation of the rods is not necessary for effective scraping and the equipment required for such rotation in conventional apparatus may be eliminated.

Since the scraper clips onto the sucker rod and may be rigidly fixed in position thereon solely under its own structural tension, it can be applied without any welding procedure, thus obviating possible danger due to arcing of the rods. Elimination of welding eliminates possible overheating which may cause localized stresses in the sucker rod.

The scraper described offers a minimum of resistance to flow of oil past its surfaces and thus permits improved pumping efliciency, while eliminating possibility of build up of parafiin on the scraper surfaces.

As indicated above, installation and removal of the scraper on the sucker rod is a simple and easy operation.

During the pumping action, sucker rods are repeatedly stretched. The scraper described, by reason of its mechanical bond to the rod, stretches with the rod whereby walking of the scraper from its original location on the rod is avoided. Moreover, in pumping, the elongation of the sucker rods reduces the cross-sectional area of the rods this permitting the loosening of conventional rigid scrapers and allowing them to move axially on the rod. The scraper described automatically compensates for the reduction in cross-section due to its qualities of spring tension.

It is possible to put a plurality of the scrapers described on a sucker rod such that each scraper could abut the next, thus further to avoid any possibility of displacement of the scrapers on the rod. This is particularly advantageous in types of wells where the movement of the scraper is extremely critical.

The scraper can be readily wound in such a manner that it would accommodate oilwell tubing of varying sizes such as 2, 2 /2, 3 or 4 inch internal diameter.

We claim:

A scraper for oil well tubing comprising a unitary length of wire comprising a scraping portion of helically extending form, said scraping portion having a longitudinal axis and at least one complete convolution of uniform radius about said axis, and a series of rod clamping portions at each end of said scraping portion, each said clamping portion having a terminal section and partial loops extending therefrom, each said partial loop of one said clamping portion being a continuation of one of said partial loops of an adjacent one of said clamping portions and forming a partial convolution extending from one to an adjacent one of said terminal sections and about said axis and being of an extent greater than e3 180 but substantially less than 360", said partial convolutions being of uniform radius about said axis, the radius of said partial convolutions being less than the radius of said scraping portion convolution, said partial convolutions of one of said series of clamping portions lying on one side of said axis, and said partial convolutions of the other of said series of clamping portions lying on the opposite side of said axis.

UNITED STATES PATENTS McKay June 30, 1903 Tripplehorn Apr. 29, 1952 FOREIGN PATENTS France June 30, 1927 Germany Apr. 5, 1928