US3036855A - Releasing spear for casing - Google Patents

Description

May 29, 1962 DV A. SIRACUSA RELEASING SPEAR FOR CASING Filed May 31, 1960 INVENTOR. DQNTEA-6//QQ aus@ ATTORN EY nited States Iid Patented May 29, 1962 3,036,855 RELEASING SPEAR FOR CASING Dante A. Siracusa, Houston, Tex., assigner to Bowen Itco, Inc., Houston, Tex., a corporation of Texas Filed May 31, 196i), Ser. No. 33,033 7 Claims. (Cl. 294-102) This invention relates to a releasing spear for casing and is `an improvement on my Patents No. 2,539,039 January 23, 195-1, and No. 2,732,249 January 24, i956, both of which patents relate to an oil well fishing spear. My present invention also relates to an oil well iishing tool whereby a lost section of pipe may be recovered from an oil well. The type of tool herein disclosed is commonly termed a spear in the industry. If a lost section of pipe, termed the fish, cannot be removed from the well due to the fact that it is stuck tightly therein, then my spear can be readily released and withdrawn from engagement with the fish without injury to the tool. The tool is lowered into the oil well and the toothed members thereof, termed the slips, fit against the inside of the lost or broken pipe. These slips are -then expanded by the tool until they are indented in the wall of the pipe, and thereafter upon exerting an upward pull the lost pipe is loosened and brought to the surface.

An object of my invention is to provide a novel resilient means at the lower end of the slips so that the slips will be frictionally held against rotation, but will be permitted to move inwardly and outwardly with relation to the mandrel of the tool by reason of their attachment to a retainer, which is termed a unitizer.

Still another object of my invention is to provide a novel spring-like structure which is coupled to lthe slip assembly in such a manner that the spring unit can move vertically into the lost pipe and frictionally engage the same, and at the same time will hold the slips against rotation relative to the lost pipe, except under a relatively high force.

Other objects, advantages and features of invention may appear from the accompanying drawing, the subjoined detailed description and the appended claims.

In the drawing:

FIGURE `l is a side elevation of my releasing spear for casing shown in position in a pipe.

FIGURE 2 is a side elevation of my releasing spear with parts broken away to show interior construction.

FIGURE 3 is a fragmentary side elevation of the spring unit adjacent the lower end of the tool.

FIGURE 4 is a sectional view taken on line 4-4 of FIG. 3.

Referring more particularly to the drawing, this invention relates primarily to an improvement in the lower portion of the tool, that is, the means of frictionally holding the slip assembly against rotation relative to the mandrel or body portion of the tool. The construction of the mandrel, the body of the tool, the slips, the method of hanging and supporting the slips at their upper ends, and the method of supporting the lower ends of the slips in a unitizer are all shown and described in my prior Patents Nos. 2,539,039 and 2,732,249. Portions of the structure already shown and described in my prior patents will again be described, at least in part.

My tishing spear for casings 1 comprises a coupling 2 which screws onto or into a string of pipe upon which the tool is run. The coupling 2 is suitably threaded to receive this pipe. A mandrel 4 depends from the coupling 2 and is threaded at its lower end to screw into a bottom nut 5. This bottom nut 5 acts as a guide to direct the tool into the lost or stuck or broken section of pipe, which is termed the fish. The mandrel 4 is a long tubular part which runs practically the entire length of the tool from the coupling 2 at the upper end to the nut 5 at the bottom.

The middle section of the mandrel 4 is formed with a plurality of superimposed tapered seats 6 which are frustro-conical in shape. The purpose of these seats is to cam the slips outwardly, as will be further described. Each of the seats 6 is formed with a horizontal shoulder '7 at its lower end. A plurality of slips 3 surround the mandrel 4 and rest on the seat 6. Each slip is formed with a plurality of tapered cam surfaces 9 which rest against the tapered seats 6. Each of the cam surfaces 9 terminate in a shoulder l@ at their upper end and this shoulder opposes the shoulder 7 on the seats 6. The slips S are `each formed with external teeth or wickers, all of which is usual and well known in the art. The slips 8, when assembled, completely encircle the mandrel 4 and particularly the area where the seats 6 are formed; thus providing a cylindrical structure which, when expanded, will engage the inside of the fish or pipe 11 with a substantially full circle engagement.

The coupling 2 may be formed with a depending annular apron l2 and each of the slips 8 are provided with an upwardly extending blade 13 which project under the apron l2. The blades i3 serve as guides or retainers for the upper part of the slips 8 and prevent these slips from falling outwardly before the tool has been inserted in the lost pipe 11. Each of the slips 8 are provided with an L-shaped slot or bayonet slot i4 and the vertical portion of this slot coincides with a vertical space 1S between adjacent blades 13. A lug 16 on the mandrel 4 extends into each or" the vertical grooves `l5 and may be moved into the bayonet slot i4 on downward movement of the mandrel 4, and subsequent rotation of the mandrel to the right while the slips 8 are being held stationary. Thus a releasable support is provided for the Slips 8 at their upper ends which permit those slips to be held in a raised position relative to the mandrel 4, that is, with the shoulders '7 and l0 contacting each other and, therefore, with the slips 8 held in a compressed or minimum diameter position.

Adjacent the `lower end of the mandrel 4l- I provide a unitizer 17 which surrounds the lower ends of the slips 8 and holds the lower ends of these slips in position around the mandrel 4. This unitizer is ixedly -attached to each or" the slips by means of the L-shaped fingers i9 which iit into correspondingly shaped slots 20 in the unitizer. The iingers 19 can move inwardly or outwardly relative to the unitizer 17, so that the slips can expand or contract, but all of the slips: are held against vertical movement relative to each other by their coupling means to the unitizer 17, that is, the lingers i9. The unitizer i7 is also formed with a vertical slot 2l which extends upwardly from the lower end thereof, and this slot receives a key 2.2 on the mandrel 4. A step 23, in the slot 2l, receives the key 22 when the mandrel 4 is lowered relative to the slips S, and when the lug le enters the bayonet slot 14.

So that the slips S may all move in unison, `and also for the purpose of permitting vertical movement of the mandrel 4 and also limited rotation thereof relative to the slips 8, I provide a spring cage 24 which surrounds the unitizer i7 and is keyed to the unitizer by means of the lug 25 which projects upwardly therefrom into a groove 26 on the outside of the unitizer. The spring cage 24 may be formed as a plurality of outwardly bent spring ingers, or it may be formed from a sleeve of spring metal which has been belled outwardly and which has then been slotted to form longitudinal fingers, substantially as shown in FlG. 3. The spring cage 24 is of sufficient outward diameter to tightly engage the lost casing or fish ll and will frictionally engage the inside of the casing, thus permitting vertical movement of the fishing tool within the casing against the friction of the spring cage. However, rotation of the cage 24 and also the unitizer 17, and therefore the slips 8, will be resisted with considerable force due to the spring finger construction of the cage 24. The spring cage 24 is held in position surrounding the sleeve portion 27 of the unitizer, by means of a snap ring 28 which is seated in the sleeve Z7 and projects slightly to act as a stop or shoulder for the spring cage 24. The spring ring 28 is positioned somewhat below the lower edge of the cage 24 to permit elongation of that cage, due to compression when the cage enters the pipe or casing l1.

In Operation My tool is lowered into the well with the slips 8 in their raised position, that is, the lugs i6 are in the bayonet slots 14 and the key 22 rests in the step 23. The nut 5 will direct the spear into the open end of the pipe or casing 1i. The spring fingers of the cage 24 will contact the inner wall of the fish and hold the unitizer 17, the spring cage 24 and the slips S stationary until the shoulders 7 engage the shoulders 1G. On downward movement of the mandrel 4 the slips 8 will now be pushed into the pipe or casing 11. The slips 8 are now in their uppermost position relative to the mandrel 4 and are compressed their maximum amount, The mandrel 4 is now rotated to the left which releases the lugs 16 from the bayonet slot 14 and moves that lug into the vertical groove 15. Simultaneously the key 22 is moved off of the step 23 and into the vertical slot 2l. The mandrel 4 can now be pulled upwardly relative to the slips 8, since the slips 8 are frictionally held against vertical movement by the spring cage 24. The cam seats 6 will now cam the slips 8 outwardly to expand these slips into a tight full circle engagement with the inside of the pipe 11.

If it is desired to release the fishing tool from the lost pipe or fish, the mandrel 4 is first moved downwardly, at which time the slips 8 are still held stationary against any downward movement by the spring cage 24. Downward movement of the mandrel 4 will move the cam surfaces 6 downward until the shoulders 7 and 10 engage. At this point the slips 8 will be in their maximum inward or compressed position and will disengage the fish il. Rotation of the mandrel 4 to the right will again engage the lugs 16 with their matching slots i4 to hold the slips in their compressed position, permitting removal of the fishing tool from the sh.

Having described my invention, I claim:

l. A releasing spear for casing comprising a coupling, a mandrel depending from the coupling, tapered seats on the mandrel, a plurality of slips surrounding the mandrel, tapered cam surfaces on said slips resting on the first named tapered seats, releasable means engaging the upper ends of each of the slips and releasably holding these slips in raised position relative to the mandrel, a unitizer slidably mounted on the mandrel for limited vertical movement on the mandrel and positioned below the slips, a finger on each of the slips at the lower end thereof, means on the unitizer engaged by the fingers to attach the unitizer to the slips, a spring cage surrounding the unitizer and projecting outwardlybeyond the periphery of the unitizer, said cage including a plurality of spring fingers.

2. A releasing spear for casing comprising a coupling, a mandrel depending from the coupling, tapered seats on the mandrel, a plurality of slips surrounding the mandrel, tapered cam surfaces on said slips resting on the first named tapered seats, releasable means engaging the upper ends of each of the slips and releasably holding these slips in raised position relative to the mandrel, a unitizer slidably mounted on the mandrel for limited vertical movement on the mandrel and positioned below the slips, a finger on each of the slips at the lower end thereof, means on the unitizer engaged by the fingers to attach the unitizer to the slips, a spring cage surrounding the unitizer and projecting outwardly beyond `the periphery of the unitizer, said cage including a plurality of spring lingers, and means nonrotatably coupling said spring means to the unitizer.

3. A releasing spear for casing comprising a coupling, a mandrel depending from the coupling, tapered seats on the mandrel, a plurality of slips surrounding the mandrel, tapered cam surfaces on said slips resting on the first named tapered seats, releaseble means engaging the upper ends of each of the slips and releasably holding these slips in raised position relative to the mandrel, a unitizer slidably mounted on the mandrel for limited vertical movement on the mandrel and positioned below 4the slips, a finger on each of the slips at the lower end thereof, means on the unitizer engaged by the fingers to attach the unitizer to the slips, and spring means mounted on the unitizer, said spring means projecting outwardly beyond the periphery of the unitizer, a key on the mandrel adjacent the lower end thereof, said unitizer having a slot therein to receive said key in one position, and a step in the unitizer adjacent the slot to receive the key in another position of the parts.

4. A releasing spear for casing comprising a coupling, a mandrel depending from the coupling, tapered seats on the mandrel, a plurality of slips surrounding the mandrel, tapered cam surfaces on said slips resting on the first named tapered seats, releasable means engaging the upper ends of each of the slips and releasably holding these slips in raised position relative to the mandrel, a unitizer slidably mounted on the mandrel for limited vertical movement on the mandrel and positioned below the slips, a finger on each of the slips at the lower end thereof, means on `the unitizer engaged by the fingers to attach the unitizer to the slips, and spring means mounted on the unitizer, said spring means projecting outwardly beyond the periphery of the unitizer, and means nonrotatably coupling said spring means to the unitizer, a key on the mandrel adjacent the lower end thereof, said unitizer having a slot therein to receive said key in one position, and a step in the unitizer adjacent the slot to receive the key in another position of the parts.

5. A releasing spear for casing comprising a coupling, -a mandrel depending from the coupling, tapered seats on the mandrel, a plurality of slips surrounding the mandrel, tapered cam surfaces on said slips resting on the first named tapered seats, releasable `means engaging the upper ends of each of the slips and releasably holding these slips in raised position relative to the mandrel, a unitizer slidably mounted on the mandrel for limited vertical movement on the mandrel and positioned below the slips, a finger on each of the slips at the lower end thereof, means on the unitizer engaged by the fingers to attach the unitizer to the slips, a spring cage surrounding the unitizer and projecting outwardly beyond the periphery of the unitizer, said cage including a plurality of spring fingers, a key on the mandrel adjacent the lower end thereof', said unitizer having a slot therein to receive said key in one position, and a step in the unitizer adjacent the slot to receive the key in another position of the parts.

6. A releasing spear for casing comprising a coupling, a mandrel depending from the coupling, tapered seats on the mandrel, a plurality of slips surrounding the mandrel, tapered cam surfaces on said slips resting on the first named tapered seats, releasable means engaging the upper ends of each of the slips and releasably holding these slips in raised position relative to the mandrel, a unitizer slidably mounted on the mandrel for limited vertical movement of the mandrel and positioned below the slips, a finger on each of the slips at the lower end thereof, means on the unitizer engaged by the fingers to attach the unitizer to the slips, a spring cage surrounding the unitizer and projecting outwardly beyond the periphery of the unitizer, said cage including a plurality of spring fingers, and means nonrotatably coupling said spring means to the unitizer, a key on the mandrel adjacent the lower end thereof, said unitizer having a slot therein to receive said key in one position, and a step in the unitizer adjacent the slot to receive the key in another position of the parts.

7. A releasing spear for casing comprising a coupling, a mandrel depending from the coupling, tapered seats on the mandrel, a plurality of slips surrounding the mandrel, tapered cam surfaces on -said slips resting on the first named tapered seats, lreleasable means engaging the upper ends of each of the slips and -releasably holding these slips in raised position relative to the mandrel, a unitizer slidably mounted on the mandrel for limited vertical movement on the mandrel and positioned below the slips, 'a linger on each of the slips at the lower end thereof, means on the unitizer engaged by the fingers to attach the unitizer Ito the slips, and spring means mounted on the unitizer, said spring means projecting outwardly beyond the periphery of the unitizer, and means nonrotatably coupling said spring means tothe unitizer consisting of a lug projecting from the spring cage, -said unitizer having a groove therein to receive said lug.

References Cited in the tile of this patent UNITED STATES PATENTS

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