US2218267A - Fishing tool - Google Patents

Description

P. 'M. REA

.FISHING TOOL Oct. 15, 1940.

Filed July 51, 1929 ZShets-Shet 1 1 Oct. 15, 1940.

P. M. REA

FISHING TOOL I Filed July 51, 1939 2 Sheets-Sheet 2 Am i lallfllllt Patented Oct. 15, 1940 UNITED STATE PATENT QFFICE FISHING TOOL Philip M. Rea, Oklahoma City, Okla.

Application July 31, 1939, Serial No. 287,567

8 Claims.

My invention relates to tools for removing cylindrical objects, such as drill pipe, tubing, and the like, from wells, and more particularly to fis ing tools of the type commonly known in the art as an overshot.

It has at the present time become customary in oil well drilling to use 5% drill stem in well casing having an inside diameter of 8 Since the tool joint of the 55+," drill stem has an outside diameter of 7", there is an annular space of only of 1%", or it wide around the tool joint. When it is considered that there must be at least a working clearance between the outside diameter of the overshot bowl and the inside diameter of the casing, this confines the combined thickness of the bowl and slips to be not over inches. In oil well fishing it is frequently necessary to exert a pull on the fish of as much as one hundred tons, and to do this with a tool having only wall thickness is a considerable problem.

It is the prime object of the present invention to provide an overshot fishing tool which will function within the limited annular space available in present oil well drilling, and which will operate successfully in lifting the required loads. The present device, made in accordance with the stipulated diameters, has been tested and with-- stood a pull of 200 tons before the bowl was sufficiently distorted to permit the slips to slide past their seating surfaces. It is believed that this is the greatest pull ever exerted upon a slip type overshot with a wall thickness of only e;- of an inch. The slips were only 3 3 of an inch thick.

Another object of the invention is to provide a thin walled overshot in which the outward thrust of the load is so distributed that distortion of the bowl is reduced to a minimum.

A still further object is to render the overshot releasable from the fish.

Another object is to make circulation of a fluid through the bowl and fish possible.

Other objects of the invention are: to insure positive engagement of the fish by the slips; to provide a tool of this class which is simple in construction; the parts of which may be easily and quickly assembled, or removed for replacement; which is durable; and, which is efficient in accomplishing all of the purposes for which it is intended.

In the drawings:

Figure l is an elevational View of the tool operatively disposed within a section of well casing;

Figure 2 is a vertical sectional view of the overshot bowl with a fish engaged by the slips thereof;

Figure 3 is a horizontal sectional view taken substantially along the line 3-3 of Fig. 2;

Figure 4 is a vertical sectional view of the bowl with the slips therein shown in perspective, the section having been taken substantially along the line 3-4 of Fig. 3;

Figure 5 is a vertical sectional view of the bowl per se, the slips having been removed, said section having been taken substantially along the line 55 of Fig. 3; and,

Figure 6 is a perspective view of one of the slip segments.

Like. characters of reference designate like parts in all of the figures.

A preferred embodiment of the invention is illustrated in the accompanying two-sheet drawings wherein:

The reference numeral I indicates a typical well casing in which is disposed a fish 2. In this instance, the fish is shown as being the end of a drill stem section, the drill stem having presumably parted at the joint, leaving the lower portion of the string in the hole. The reference numeral 3 indicates the narrow annular space within which the tool is designed to function. i indicates thelower end of a fishing string which is adapted to be threaded into threads 5 in the upper end of a suitable tubular sub 6. The parts thus far described are usual and are not a part of the invention per se. The invention includes and is embodied within a tubular bowl ill having its upper end interiorly threaded at H to engage the lower end of the sub 6.

The bowl l8 has a bore l2 extending from its upper end downwardly to adjacent its lower end Where it is tapered inwardly to form a slip seat l3. Below the slip seat E3, the bore of the bowl is cylindrical. This portion of the bowl is cylindrical. This portion of the bowl is indicated by the reference numeral M. The lower end of the bowl I6 is exteriorly threaded at [5 to receive the upper end of a tubular guide shoe IS. The shoe it may be of any usual form for guiding the fish into the bowl, for instance, it may be a usual milling tool, wall hook, or the like.

The slip seat i3 is not continuously annular, but is divided into four radially spaced seats which are formed by keys I! made integrally with the inner wall of the bowl Ill and extending above the slip seat it. The four radially spaced inwardly projecting keys I! have their upper ends inwardly and downwardly tapered to form additional or auxiliary slip seating surfaces l8, and, as is apparent in Fig. 5, the seating surfaces 28 are radially staggered with relation to the slip seats IS.

A pair of identical slip segments l9 and 20 are provided for seating upon the slip seats l3 and I8, and their operative positions are best shown in Fig. 4. The element i9 is set apart and is detailed in Fig. 6, and consists substantially of a semi-circular sleeve having depending radially spaced legs 2| adapted to fit within the interstices between the keys I! of the bowl, and each leg having a tapered lower end portion 22 adapted to register with and seat upon the spaced slip seats I3 of the bowl. Intermediate the legs 2|, the slip segments l9 and 210 each have tapered outer surfaces 23 adapted to register with and seat upon the seating surfaces E8 on the upper ends of the keys H. The meeting surfaces or edges of the slip segments l9 and 20 are preferably complementally step-cut as shown at 26 so that when they are in operative position within the bowl, they must move in unison. The inner surfaces of the slip segments I9 and 20 are provided with continuous complemental threads 25 so that they may be unscrewed from the fish if desired. The slip segments are installed within the bowl ID by merely dropping them into place upon the seats l3 and i8.

Above the slips and within the bowl i0, is provided a resilient annular sealing element 26 adapted to seal between the bowl and the fish 2. The element 26 is urged into contact with the upper ends of the slip segments by a tubular follower 21 and a compression spring 28. The lower end of the body section 6 acts to maintain the spring 28 under compression.

Obviously, the action of the spring acts to force the slip segments downwardly upon their seats so that they will immediately engage a fish upon its insertion into the slips.

In operation, as the bowl is lowered over the fish 2, the slip segments l9 and 2t are moved upwardly, by contact with the fish, a sufficient distance against the action of the spring 28 to permit their lateral movement away from each other, thus permitting entry of the fish into the slips. When the bowl is subsequently raised by upward movement of the string l, the slips move slightly downwardly upon theirseats l3 and i8 and are forced thereby into frictional engagement with the fish.

Since the slips are made of a material which is harder than the fish, the threads 25 cut into the exterior surface of the fish. Should it then be found desirable to release the fish, the bowl may be lowered sufficiently to relieve the wedging action of the slip seats, and rotation of the bowl will then act to unscrew the slips from the fish. The keys I! and legs 2|, of course, cause the slips to rotate with the bowl.

It is pointed out that since the keys I! are part of the bowl and also act as seats, and since the slip segments have the two tapered surfaces 22 and 23, there is no occasion to use an auxiliary key to prevent rotation of the slips with relation to the bowl. Consequently, neither the slips nor the bowl is weakened by providing for a key arrangement as is necessary with usual releasing overshots. Also, there are two vertically spaced seats each having substantially 360 degrees of seating contact. This arrangement permits both the bowl and slips to be made stronger than usual overshots designed to operate in an annular space of like dimensions.

Obviously more than one set of slips may be embodied in a single bowl, if desired.

The sealing element 26 renders it possible to obtain fluid circulation through the fish in order to assist in loosening it from the well.

I claim:

1. In an overshot fishing tool: a tubular bowl; a set of radially spaced tapered slip seating surfaces in the bore of the bowl; a second set of radially spaced tapered slip seating surfaces in the bowl beneath the first set, said second set being staggered radially with relation to the first set; and, a set of segmental pipe slips removably disposed within said bowl and having tapered surfaces corresponding to and adapted to seat upon both of said sets of slip seating surfaces.

2. In an overshot fishing tool: a tubular bowl; a set of radially spaced tapered slip seating surfaces in the bore of the bowl; a second set of radially spaced tapered slip seating surfaces in the bowl beneath the first set, said second set being staggered radially with relation to the first set; and, a set of interiorly threaded segmental pipe slips removably disposed within said bowl and having tapered surfaces corresponding to and adapted to seat upon both of said sets of slip seating surfaces.

3. Organization as described in claim 1, in which the meeting edges of the slip segments intermesh to prevent their independent longitudinal movement.

4. Organization as described in claim 1, in which each slip segment comprises: an upper body arcuate in cross-section and having exterior radially spaced tapered seating surfaces; radially spaced legs extending downwardly from said body and located between the seating surfaces thereof; and, an exterior tapered seating surface carried by each of said legs.

5. Organization as described in claim 1, in which each slip segment comprises: an upper body arcuate in cross-section and having exterior radially spaced tapered seating surfaces at its lower end; radially spaced legs extending downwardly from saidbody and located between the seating surfaces thereof; and, an exterior tapered seating surface carried by the lower end of each of said legs.

6. Organization as described in claim 1, in which each slip segment comprises: an upper body arcuate in cross-section and having exterior radially spaced tapered seating surfaces; radially spaced legs extending downwardly from said body and located between the seating surfaces thereof: and, an exterior tapered seating surface carried by each of said legs, the side edges of said legs acting to prevent independent rotation of the slip segments in the bowl, by co-action with the side edges of the vertically extending portions of the bowl which lie between its sets of slip seating surfaces.

7. An overshot fishing tool including: a tubular bowl; a series of radially spaced tapered slip seat'mg surfaces in the bore of the bowl; a second series of similar slip seating surfaces in said bowl beneath the first series and radially staggered with relation thereto; and, a set of segmental slips having seating surfaces for seating upon both series of seating surfaces in said bowl.

8. An overshot fishing tool including: a set of segmental pipe slips each segment of which comprises an upper body arcuate in cross-section and having exterior radially spaced tapered seating surfaces; radially spaced legs extending downwardly from said body and located between the seating surfaces thereof; an exterior tapered seating surface carried by each leg; and, a tubular bowl for receiving said slips, the bore of said bowl having tapered slip seating surfaces for contacting and seating all of the seating surfaces of said slips.

PHILIP M. REA.

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