US2670046A - Casing scraper - Google Patents

Description

Feb. 23, 1954 z ci-l 2,670,046

CASING SCRAPER Filed Jan. 5, 1950 Z I 1 I5 i l2a l j. 7' l 19 7 INVENTOR: Haber! B. Km bach ATTORN E Y Patented Feb. 23, 1954 UNITED STATES PATENT OFFICEJ CASING SCRAPER Robert B. Kinzbach, Houston, Tex. Application January 3, 1950, Serial No. 136,449

1 This invention relates to a casing scraper.

An object of the invention is to provide a tool of the character described for smoothing and conditioning the inside of a casing, or other pipe, set in a well bore.

In carrying on operations in a Well, the interior of the casing should be kept as smooth and as nearly round as possible so as not to interfere with said operations nor to injure the tools or equipment by means of which the operations are carried on; for example, well casing is often perforated opposite potentially productive strata by what is commonly known as a well shooting gun, and if no oil is produced therefrom the perforations are cemented up by filling the casing with cement opposite said perforations and allowing it to set around and within the casing. Thereafter, the cement is often drilled out of the casing in order to carry on operations beneath, and the casing should be smoothed, interiorly, in order to condition it for the carrying on of such operations through it.

It is the object of the present invention to provide a casing scraper which can be incorporated into the drill stem adjacent the drill and by means of which the casing may be scraped, smoothed and conditioned simultaneously with the drilling out process.

Another object is to provide a tool of the character described which will remove inwardly extending projections from the pipe such as burrs or bullets or the like.

Of course, the tool may be used in tubular ob jects anywhere for the purpose indicated.

Other objects and advantages will be apparent from the following specification, which is illustrated by the accompanying drawings, wherein:

Figure l is a side elevation of the tool, partly in section, shown connected into a drill stem and associated with a drill used in drilling out the well casing;

Figure 2 is a side elevation, partly in section, of a cutter;

Figure 3 is a cross-sectional view of the scraper taken on the line 3-3 of Figure 1;

Figure l is a cross-sectional view taken on the line i l of Figure 1; and

Figure 5 is an enlarged, cross-sectional view taken on the line 5-5 of Figure 1.

Referring now more particularly to the drawings, wherein like numerals of reference designate the same parts in each of the figures, the numeral 5 designates the scraper body, which, in the present illustration, is of a general cylindrical shape and whose upper end is formed with a reduced, outwardly threaded, tapering pin 2 for the connection of an operating string 3 to the body. This string 3 may extend to the ground surface. v

The lower end of the body I may be provided 5 Claims. (01. 166-18) with an internally threaded, downwardly flaredbox 4 to receive the externally threaded shank of a drill 5.

Of course, the drill may be employed only when the well has become obstructed by cement, as 6,-

ly, whose outer ends have the opposing sockets- 9 and ID.

Within the bearing members or housings are the upper and lower yieldable elements ll, l2 which react against the bottom of the respective bearings and the outer ends of the housings l, 8 so as to independently hold said housings yieldably outwardly. These elements may vary in resistance, the stronger elements being so located as to hold the driving teeth most firmly against the inside wall of the casing.

The upper and lower ends of each cutter Ha are reduced and formed into extended necks which terminate in ball joints l3, l4 that work independently in the opposing sockets 9, Ill, as shown in Figure 1. These tapered cutters work in the pockets 6a but project out beyond the surface of the body so as to contact the inner wall' of the casing when inserted therein, and the inde-' pendently yieldable housings I and 8 cause them' to cant their axes to that of the body until line contact is secured between the periphery of the cutters and the pipe wall to be scraped.

Each cutter includes the driving and scraping" teeth I6, which may be helical, and these teethf required distance apart around may be spaced the the body, and the the body.

teeth extend longitudinally of The housings l, 8 have side keyways l'l, ll,

which extend out radially, and keys, as l8, are

threaded into the body l at right angles to said keyways and with their inner, smooth ends projecting into the keyways so as to retain the housings against detachment, and these keys are locked in place by means of locknuts 19.

In operation, the body I is rotated, causing a corresponding rotative movement of the cutters due to the pressure contact between their teeth.

and the pipe wall. Inasmuch as the circumferences of the cutters vary from end to end, while that of the pipe it contacts is constant, the rotative speed of the cutters will correspond to that of only one diameter (usually the largest because.

of the greater torque at this point) and relative slippage must occur throughout the balance of the length of the cutter. The magnitude of this slippageis controlled by the difference in cutter.-

tapered diameters. This slippage provide the wall scraping action.

Due to independent radial movement of end bearings, the cutters are yieldably forced into line contact with the inner wall or the casing. In this position the cutter axis is canted to the body axis by half the included angle of the tapered cutter.

As the body is rotated with the cutters in this position, they are caused to rotate about their axes by the drag of their teeth against the sta tionary wall of the casing.

Since the cutters are conical in shape, their larger diameter end will tend to control their rotative speed to a valve corresponding to the circumferential casing surface traversed divided by the circumference of the cutter at its larger end. Since the circumference of the smaller end f the cutter cannot cover this same circumferential distance in the casing at this speed relative slippage must occur, starting at zero at the large diameter end and increasing to a maximum at the small diameter end. By the same reasoning, if the smaller end of the cutter happens to control cutter rotative speed, due to its encountering irregularities of suflicient drag to overcome the torque drag at the larger end, then cutter rotative speed will be controlled as a function of this diameter, and slippage will occur to a maximum value at the larger diameter end.

in elTect this design provides a combination of circumferential chipping and sliding action against the casing wall for the removal of burrs, cement coating, and the like.

The housings =7, 8 will break major obstructions in the and the cutters in rolling will scrape the wall smooth. Each cutter is tapered and frusto-conical in shapeand has longitudinal teeth spacedabout its periphery.

The drawings and description are (illustrative merely, while the broad principle of the invent-ion will Ice-defined by the-appended-claims.

What .I claim is:

1-. A tool of the character described comprising, a body, rolling cutters, end bearings mounted on the body for supporting said cutters, at their -op-.

posite ends for independent angular movement relative to the bearings and independent radial movement relative to said body, and yieldable means cooperable with said bearings and body to yielding-1y .hold said bearings outwardly with respect to the body, said bearings also shaped to form bumpers for the removal of major obstructions ahead of roller contact.

2. A tool of the character described comprising a body adapted to be connected to an operating string for rotation with the string and having outwardly opening pockets therein, outwardly opening aligned recesses above and below each of 'saidpockets, a bearing member in each 'of'said recesses extending outwardly beyond the body and movable inwardly and outwardly thereof, a frusto-conical rolling cutter rotatably mounted at its opposite ends between the bearing-members o'f each of the pockets 'for independent angular movement relative thereto, resilient-means in the recesses :in engagement with the body and :said heating members and :urging said :members routwardly of said recesses and stop means on the body engageable with said "bearing members to limit outward movement of the bearing members.

3. 'A-toolior the character described comprising a cy-lindrically shaped body adapted to be conneoted at one end to'an operating string for rota-- tion with the string, said body having z-p'erinher-a 4 ally-spaced, vertically-elongated outwardly-opening pockets therein and an outwardly-opening radially-extending bearing recess beyond each end of each of said pockets and in alignment therewith, a bearing member positioned'in each of said recesses and extending outwardly thereof, said bearing members being movable inwardly and outwardly of the recesses, a rolling cutter rotatably mounted at its opposite ends in the bearing members of each pocket for independent angular movement relative thereto, and resilient means in said recesses between said body and said bearing members and cooperable with the body and said members to urge said members outwardly of the recesses.

4. A tool of the character described comprising a cylindrically shaped body adapted to be connected at one end to an operative string to retate with the operating string said body having radially-disposed vertically-elongated outwardlyopenin-g pockets therein, and a radially-extending outwardly-opening bearing recess above and beneath each of said pockets and aligned therewith, a bearing member positioned ineaeh of said recesses and substantially closing the same, said bearing members extending outwardly beyond the body and being independently movable inwardly and outwardly of the recesses, a rolling cutter positioned between and .rotatably mounted at its opposite ends in the bearing member o-f each pocket for independent angular movement relative thereto, resilient means in said recesses, engageable with said body and said bearing membars to .yieldingly resist movement of said members inwardly 'oi said recesses, and-stopmeans on the body engageable with .said members to limit outward movement of said members in .said recesses.

5. A tool of the character described comprising a eylindrically shaped'body adapted to be connectedat one end toan operating string for-rotation with the string and having outwardly-opening vertically-elongated, pockets therein, and aligned, outwardly-openi-ng.bearing recesses .beyond the ends of each of the pockets, a bearing member positioned in each recess for movement inwardly and outwardly thereof and extending outwardly beyond the body, a frusto-conical rolling cutter rotatably mounted-rat its opposite ends in the bearing members of each pocket .for independent angular movement relative thereto, resilient imeans positioned irl said recesses and engage-able with :said body and said bearing members to urge said cutters away from said body, and stop meanson the body engageable with the bearing members to limit outward movement of the members.

ROBERT B. KINZBAGH.

References Cited in 'thefiile o'fth'is patent srAr-Es PATENTS 179,850 Germany .1907

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