US3746093A

US3746093A - Releasable locking system for a well tool

Info

Publication number: US3746093A
Application number: US00257367A
Authority: US
Inventors: A Mullins
Original assignee: Schlumberger Technology Corp
Current assignee: Schlumberger Technology Corp
Priority date: 1972-05-26
Filing date: 1972-05-26
Publication date: 1973-07-17
Anticipated expiration: 1990-07-17
Also published as: CA955522A

Abstract

In accordance with an illustrative embodiment of the present invention, a new and improved locking system for locking and releasing parts of a well tool in a well bore is incorporated between members that are movable longitudinally relative to one another. The locking system includes a lock ring having gripping engagement with one member, and cam means that causes the lock ring to grip the member when in one position and movable to another position that enables the lock ring to pass longitudinally therethrough. After passage through the cam means, the lock ring is received within a recess on the other member so that the said other member can move freely along the one member upon disengagement of the cam means.

Description

[ RELEASABLE LOCKING SYSTEM FOR A WELL TOOL Albert A. Mullins, Richmond, Tex.

[73] Assignee: Schlumberger Technology Corporation, New York, N.Y.

[22] Filed: May 26, 1972 [21] Appl. No.: 257,367

[75] Inventor:

[52] US. Cl 166/217, 166/123, 166/134,

166/237 [51] Int. Cl E21b 23/06, E2lb 33/129 [58] Field of Search 166/120, 123, 134, 166/135, 237, 238, 216, 217

[56]. References Cited UNITED STATES PATENTS 3,136,364 6/1964 Myers 166/120 3,282,342 11/1966 Mott 166/120 3,361,209 1/1968 Edwards t. 166/120 3,422,898 l/ 1969 Conrad 166/237 X 3,456,723 7/1969 Current et a1. t. 166/ 120 3,552,489 1/1971 Berryman 166/120 1' July 17, 1973 Randermann 166/217 X Primary Examiner-David H. Brown A tt5 Ffiky ifii esT1i. Archambeall, Jr., David L. Moseley et al.

[57] ABSTRACT In accordance with an illustrative embodiment of the present invention, a new and improved locking system for locking and releasing parts of a well tool in a well bore is incorporated between members that are movable longitudinally relative to one another. The locking system includes a lock ring having gripping engagement with one member, and cam means that causes the lock ring to grip the member when in one position and movable to another position that enables the lock ring to pass longitudinally therethrough. After passage through the cam means, the lock ring is received within a recess on the other member so that the said other member can move freely along the one member upon disengagement of the cam means.

12 Claims, 8 Drawing Figures 111 3,746,093 1451 July 17,1973

United States Patent 11 1 Mullins FIG. 7A

4 Sheets-Sheet l.

F/GIB 59 Patented July 17, 1973 3,746,093

4 Sheets-Sheet 2 Patented July 17, 1973 4 Sheets-Sheet 3 FIG. 5A

RELEASABLE LOCKING SYSTEM FOR A WELL TOOL This invention relates generally to well tools used in well bores, and more particularly to a retrievable well tool that incorporates a uniquely arranged locking system that functions to lock the tool in the set position in the well, the lock system being releasable in such a manner that complete retraction of parts is assured.

In quite a number of well tools such as bridge plugs, packers and tubing anchors, certain parts are moved longitudinally relative to each other to cause lateral or expansive movement of other parts in order to set the tool in a well bore. For example, a mandrel might be moved longitudinally relative to an outer sleeve to cause compression and expansion of normally retracted packing elements, or relative to an expander to cause outward shifting of normally retracted slip elements. In order to secure the well tool in set position, one way lock systems may be utilized that permit relative movement in one direction but prevent movement in the opposite direction to retain the packing and slip elements in outer positions. Thus the tool is locked in the set position until such time as it becomes desirable to remove it from the well.

In order to retrieve the tool from the well, it is desirable to be able to positively and reliably release the one-way lock systems to enable movement in the opposite or reverse direction so that the packing and slip elements can return to their normally retracted positions. In the past, such lock systems upon release incorporated structure succeptable to binding due to friction and other factors, with the result that the slip elements, for example, were only partially released and were unable to return to their fully retracted position. Unless complete retraction is assured, however, difficulty may be encountered in actually retrieving the tool from the well intact.

It is the leading object of this invention to provide a new and improved releasable one-way lock system for retaining parts of a well tool in set positions, the lock system being constructed and arranged whereby upon release thereof complete retraction of the expanded parts is obtained.

This and other objects are attained in accordance with the concepts of the present invention through the provision of a releasable locking system comprising first and second members movable longitudinally relative to one another, and a locking means that permits movement in one direction but normally prevents movement in the opposite direction. The locking means incudes a lock member having gripping engagement with the first member, and a cam means engaging the second member and causing the lock member to grip the first member when in one position and movable to another position to enable the lock member to pass longitudinally therethrough. A holding means positions the cam means in said one position and includes relief means to enable movement of the cam means to the other position, and after passage of the lock member through the cam means the lock means is received within a recess within the second member so that free relative movement in the opposite direction is assured. Such free relative movement enables complete retraction of parts of a well tool to occur without hindrance, so that the tool can be readily removed from the well bore.

The present invention has other objects and advantages which will become more clearly apparent in connection with the following detailed description of a preferred embodiment thereof, taken in conjunction with the accompanying drawings in which:

FIGS. 1A and 1B are longitudinal sectional views, with portions in side elevation, of a well packer that incorporates releasable locking systems in accordance with the principles of the present invention and with parts in the relative positions they occupy during running into a well bore, FIG. 1B forming a lower continuation of FIG. 1A;

FIGS. 2 and 3 are cross-sections taken on lines 2-2 and 33 of FIGS. 1A and 18, respectively;

FIGS. 4A and 4B are views similar to FIGS. 1A and 1B except with parts in relative positions when the tool is set in a well casing; and

FIGS. 5A and 5B are views similar to the foregoing except showing the parts in position for retrieving the tool from a well.

Referring initially to FIGS. 1A and 1B for a detailed description of a permanent or retrievable well packer that incorporates releasable lock systems constructed in accordance with the principles of the present invention, an elongated mandrel having a full opening throughbore 11 carries a set 12 of normally retracted slip elements 13 that are disposed between an upper expander 14 and a lower expander 15. The lower expander 15 is fixed to the mandrel 10 by virtue of being threaded to a ring 16 which is threaded to the mandrel, whereas the upper expander 14 is movable relatively therealong. A nose piece 17 is fixed to the mandrel 10 below the lower expander 15. The slip elements 13 are maintained in the same horizontal plane by a band 18 that encircles the elements and engages within an inwardly directed recess 19 in each slip element. Each slip element 13 has spaced upper and lower sets of wickers or

teeth

20 and 21, and has inner

inclined surfaces

22 and 23 that are engaged by companion

outer surfaces

24 and 25 on the respective expanders in order to cause outward shifting of the slip elements in response to movement of the upper expander 14 relatively toward the lower expander 15. Each end of each slip element 13 may be provided with a retractor structure including slidable connections to the adjacent expander so that movement of the upper expander 14 relatively away from the lower expander 15 will cause inward movement of the slip elements to retracted positions. For further detail of the slidable connections, attention is invited to Application Ser. No. 57,086, filed concurrently herewith and assigned to the assignee of this invention.

The mandrel 10 also carries a packing assembly that comprises several

elastomeric packing rings

31, 32 and 33 mounted around well tubular compression sleeve 34 that is movable relatively along the mandrel. The upper packingring 31 is engaged by a downwardly facing abutment 35 that is fixed to the sleeve 34, and the lower ring 33 is engaged by an upwardly facing abutment 36 that is movable relatively along the sleeve above an enlarged section 37 thereof provided at its lower end. Of course it will be recognized that movement of the

abutments

35 and 36 relatively toward one another will cause the

packing rings

31, 32 and 33 to be compressed and expanded into sealing contact with a wall casing wall.

The lower abutment 36 is coupled to the upper expander 14 through the medium of an intervening sleeve 38. Within limits, the sleeve 38 can move longitudinally relative to both the upper expander 14 and the compression sleeve 34. Limited movement with respect to the upper expander 14 is afforded through the provision of one or more outwardly extending plugs 39 that are threaded within openings in a reduced diameter upper section 40 of the expander, and which extend into elongated slots 41 through the wall of the sleeve 38, whereas limited movement with respect to the compression sleeve 34 is afforded by similar arrangement including a plug 42 on the section 37 that extends into an elongated slot 43 through the wall of the sleeve 34. Of course the respective plugs and slots also function to prevent relative rotation of the parts. Moreover, in the initial positions of the parts, the intervening sleeve 38 is relatively fixed by

shear pins

44 and 45 that extend through the wall of the sleeve and into the enlarged section 37 and the upper portion 40 of the expander 14, respectively. With the parts in the runningin position shown in FIG. 1B, the lower end surface 46 of the sleeve 38 engages an upwardy facing shoulder 47 on the upper expander 14 so as to be able to drive the upper expander downwardly along the mandrel 10.

A releasable, one-way lock system indicated generally at 50 is disposed above the upper end surface 51 of the upper expander 14, and between the mandrel and the intervening sleeve 38. The lock system 50 includes a split ratchet or lock ring 52 that normally is surrounded by a split cam ring 53 which is adapted to be held in an inner position as shown by an internal locking surface 54 on the intervening sleeve 38. The ratchet ring 52 has internal teeth 55 that can mesh with external teeth 56 formed, for example, by threads on an adjacent section of the mandrel 10. Moreover, the ring 52 has upwardly and outwardy inclined cam surfaces 57 on its outer periphery that are engaged by companion cam surfaces 58 formed interiorly of the cam ring 53. The ratchet ring 52, by virtue of its split construction as shown in FIG. 2, has the capability for lateral expansion and contraction and can therefore ratchet downwardly along the mandrel teeth 56 in response to downward force imposed upon the cam ring 53 by the inwardly directed shoulder 59 on the intervening sleeve 38 during downward movement of the latter, however the ratchet and cam rings cannot be moved jointly upwardly along the mandrel 10 by the expander 14 due to the camming action of the

surfaces

57 and 58 which causes the ratchet ring to be forced inwardly and to tightly grip the mandrel. The lock system 50 can be released, however, by moving the intervening sleeve 38 upwardly relative to the mandrel 10 and the expander 14 to position an enlarged diameter relief recess 60 adjacent the cam ring 53. When this occurs, the cam ring 53 due its split or segmented construction as shown in FIG. 2, can expand outwardly to a throughbore size such that it can pass upwardly over the ring 52 without interference therewith. An elongated counterbore provides an internal annular recess 61 within the upper end section of the upper expander 14, and the recess is sized to receive the ratchet ring 52 as the upper expander moves upwardly along the mandrel 10.

Turning now to FIG. 1A, it will be seen that the upper abutment 35 is formed in part by the lower end surface of a sleeve extension 65 that is threadedly fixed to the compression sleeve 34. The sleeve extension 65 extends upwardly along the upper end portion of the mandrel 10, and the lower end portion 66 of a releasing sleeve 67 is telescoped over the extension 65. Hereagain, the release sleeve 67 has some capability for limited vertical movement relative to the extension 65 due to the provision of opposed stop shoulders 68 and 69 that may be conveniently formed on the respective member by threads as shown in cut-away elevation. Relative rotation is prevented by virtue of a plug 70 fixed to the extension and engaging within an elongated slot 71 through the wall of the release sleeve. It will be appreciated of course that the release sleeve 67 and extension 65 are initially fixed together by means of a shear pin 72 or the like.

A second releasable one-way lock system 75 is disposed between the upper end portion 76 of the mandrel 10 and the release sleeve 67, and also comprises a split ratchet ring 77 (FIG. 3) having internal teeth 78 that mesh with external teeth 79 on the mandrel. The outer cam surfaces 80 of the ratchet ring 77 are engaged by internal cam surfaces 81 formed on enlarged head portions 82 of a plurality of circumferentially spaced spring fingers 83 that depend from the lower end of a latch sleeve 84 fitted within the release sleeve 67, the spring fingers being formed by slots 85 that are cut from the lower end of the latch sleeve 84. Normally, the head portions 82 are held inwardly, as shown, by locking surfaces 86 and '87 that are formed by stepped diameter inner wall portions of the release sleeve 67. ln a fashion similar to the first lock system described above, the upper lock system 75 permits the release sleeve 67 and the extension 65 to be moved jointly downwardly along the mandrel 10 as the ratchet ring 77 ratchets over the mandrel threads 79, however the parts cannot return upwardly due to the coaction of the cam surfaces 80 and 81 and the resultant inward camming action on the ratchet ring. Consequently, the packing assembly 30 can be locked with the

rings

30, 31 and 32 in expanded condition and will remain in such condition until it is desirable to retract them. Retraction is accomplished through release of the lock system 75 by lowering into the well an inside grapple type tool that engages the internal threads 88 at the upper end of the release sleeve 67. An upward pull on the sleeve 67 results in shearing of the pin 72 so that the sleeve can telescope upwardly over the extension 65 and the latch sleeve 84, thus removing the locking surfaces 86 and 87 from around the head portions 82. Unsupported against outward movement, the head portions 82 are free to resile outwardly so that theycan pass upwardly over the ratchet ring 77, thereby enabling the sleeve extension 65 and the compression sleeve 34 to move upwardly along the mandrel l0 and relieve the compression loading in the packing rings 30, 31 and 32. The extension 65 is also provided by an elongated internal annular recess 89 that is sized to receive the ratchet ring 77 during such upward movement. Upward movement of the release sleeve 67 along the extension 65 is of course stopped by engagement of the inwardly directed shoulder 68 on the sleeve with the outwardly directed shoulder on of the extension.

The latch sleeve 84 has threads 90 formed internally at its upper end for reception of a typical latching mechanism on a seal mandrel (not shown) that forms the lower end of a production string of pipe, an exemplary structure that is suitable for this purpose being shown in U. S. Pat. No. 2,737,248. The presence of a tensile strain in the production string will not affect the locked condition of the lock system 75, since upward force only causes the ratchet ring 77 to grip the mandrel more tightly. Since the seal mandrel and associated latching system noted above are released by relative rotation, a lock pin 91 on the release sleeve 67 extends into a groove 92 at the upper end of the latch sleeve 84 to prevent co-rotation of the latter mentioned part.

In operation, the parts are assembled as shown in the drawings and the assembly is coupled to a conventional gas operated setting tool (not shown) for lowering to the desired setting depth in a well casing. The setting tool is releasably connected to the packer through instrumentalities including a tension member 100 and an adapter sleeve 101 shown in FIGS. 1A and 1B. The tension member 100 includes a central rod 102 having its lower end connected to a frangible tension stud 103 having a reduced neck providing a weak point 104, the lower end of the tension stud being threaded to a bottom cap 105. The cap 105 has a coupling sleeve 106 extending upwardly therefrom, and the coupling sleeve carries a split ring 107 operatively engaged between an upwardly facing shoulder 108 thereon and a downwardly facing shoulder 109 presented by the lower end surface of the mandrel 10. A holding and releasing member 110 is received over the upper end portion of the coupling sleeve 106, and comprises a skirt 1 l1 having an external annular recess 112 in which the split ring 107 is held. The member 110 also includes inwardly directed flange portion 113 that is disposed in spaced relation above an outwardly directed flange 1 14 on the rod 102. Moreover, an upwardly facing shoulder 115 is arranged in vertical alignment with a downwardly facing shoulder 116 on the coupling sleeve 106. As long as the tension stud 103 remains intact, the split ring 107 is engaged within the annular recess 117 formed in the nose piece 17 below the shoulder 109.

The adapter sleeve 101 has a drive surface 120 which engages the upper end face 121 of the latch release sleeve 67. As will be appreciated by those skilled in the art, activation of the setting tool will cause upward movement of the tension rod 102 and downward movement of the adapter sleeve 101. In response to the resultant movement in opposite longitudinal directions, the packer is set in the following manner. Inasmuch as the latch release sleeve 67 is in driving contact with the extension 65 of the compression sleeve 34, the compression sleeve and its upper abutment 35 will be shifted downwardly relatively along the mandrel 10, which is simultaneously being pulled upwardly. As the release sleeve 67 and the compression sleeve 34 move downwardly, the latch sleeve 84 is also driven downwardly by virtue of the shoulder formed by the stepped locking

surfaces

86 and 87. As previously described, the ratchet ring 77 has capability of sufficient lateral expansion and contraction within the head portions 82 whereby it can ratchet downwardly over the mandrel threads 79.

As the compression sleeve 34 moves downwardly along the mandrel 10, the intervening sleeve 38 between the lower abutment 36 and the upper expander 14 is also moved downwardly, resulting in advancement of the upper expander toward the lower expander which is fixed to the mandrel. Thus the slip elements 13 are shifted outwardly until their teeth and 21 bite into and grip the well casing wall as shown in FIG. 4B

to anchor the tool against longitudinal movement. As the intervening sleeve 38 and the upper expander 14 move downwardly, the shoulder 59 drives the one-way lock system 50 downwardly along the mandrel 10, and as described above the ratchet ring 52 ratchets along the threads 56 and traps the extent of downward movement of the upper expander 14. Since the ratchet and cam rings cannot be moved jointly upwardly, it will be apparent that the slip elements 13 are locked by the system 50 in set or expanded positions.

Once the slip elements 13 are set against the casing C, the intervening sleeve 38 and the lower abutment 36 cannot be moved any further downwardly. Consequently, continued downward movement of the compression sleeve 34 and the upper abutment 35 results in shearing of the pins 44, whereupon the upper abutment moves toward the lower abutment 36 to compress the packing rings 31, 32 and 33 and expand them into sealing contact with the surrounding well casing wall. The upper one-way lock system prevents upward movement of the compression sleeve 34 and thereby traps the packing in expanded condition, whereby the packer is fully set in the casing C.

At a predetermined magnitude of tensile strain in the rod 102, which magnitude is somewhat above that required to fully set the packer, the tension stud 103 fails at the weak point 104 as shown in FIG. 4B. Upward movement of the rod 102 brings the flange 113 against the holding member and moves it upwardly relative to the mandrel 10, whereupon the split ring 107 is permitted to resile inwardly and disengage from the recess 117. The result is to disconnect the coupling assembly from the mandrel 10 as shown in FIG. 4B, whereupon the setting tool is released from the packer and can be withdrawn from the well. The lower shoulder on the rod 102 picks up the member 106 and the cap 105 so that nothing is left in the well as a result of the setting procedure.

With the packer firmly set in the casing C as shown in FIGS. 4A and 4B, a production string can be lowered into the well and connected to the packer. A seal mandrel and latch sleeve as referred to above can be connected to the lower end of the production string, the seal mandrel extending into the bore 11 of the packer mandrel 10 and being fluidly sealed with respect thereto, the latch engaging the internal threads 88 at the upper end of the latch sleeve 84 to provide a coupling. The packer isolates the producing zone and confines the pressure of the production fluids to the production string of tubing that extends upwardly to the surface.

To release the packer for retrieval to the surface, the production string is removed, and an inside grappletype retrieving tool 125 shown schematically in FIG. 5A is lowered into the well on a pipe string and connected to the internal threads 90 at the upper end of the releasing sleeve 67. A sufficient upward pull on the releasing sleeve 67 will cause the pin 72 to be sheared to enable upward movement of the release sleeve relative to the mandrel 10 until the shoulder 69 thereon abuts the shoulder 68 on the extension 65. Such movement removes the locking surfaces 86 and 87 from around the latch heads 82, and enables the heads and the fingers 83 to resile outwardly and pass upwardly over the ratchet ring 77, which remains stationary with respect to the mandrel 10. This permits upward movement of the compression sleeve 34 and relief of the compression loading in the packing rings 31, 32 and 33 so that they will inherently retract. Upward movement of the compression sleeve 34 is completely unimpeded, since the ratchet ring 77 is received within the recess 89.

When the lower enlarged section 37 of the compression sleeve 34 engages the lower abutment 36, the pins 45 are sheared and the intervening sleeve 38 is drawn upwardly relative to the mandrel and to the upper expander 14. Accordingly, the lock surface 54 is removed upwardly from around the cam ring 53 so that it can move outwardly into the recess 60 and upwardly over the ratchet ring 52. When the plugs 39 engage the lower ends of the slots 41, the upper expander 14 is pulled upwardly with respect to the slip elements 13. During upward movement of the expander 14 the ratchet ring 52, which remains stationary with respect to the mandrel 10, is received within the recess 61 and does not impede such upward movement. Movement of the upper expander 14 away from the lower expander results in complete retraction of the slip elements 13 as shown in FIG. 5B. With the packing and the slips retracted, the packer can be retrieved intact to the surface.

It will now be apparent that a new and improved locking system has been provided that enables complete retraction of packing and slip elements after they have been set in a locked position in a well casing. Inasmuch as the principle locking element, that is the lock ring that grips the mandrel, need not be advanced in the reverse direction during retraction of the expanded well tool part, it will be apparent that all substantial binding action is completely eliminated.

Since certain changes or modifications may be made in the disclosed embodiment without departing from the inventive concepts involved, it is the aim of the appended claims to cover all such changes and modifications falling within the true spirit and scope of the present invention.

I claim:

1. Apparatus for use in a well tool, comprising: a first member; a second member movable relatively along said first member; releasable means for permitting movement of said second member along said first member in one direction but normally preventing movement in the opposite direction, including a lock member having gripping engagement with said first member, cam means engaging said second member and causing said lock member to grip said first member when in one position and movable to another position to enable said lock member to pass longitudinally therethrough, holding means for positioning said cam means in said one position and means to enable movement of said cam means to said other position; and recess means in said second member for receiving said lock member after passage thereof through said cam means and during movement of said second member along said first member in said opposite direction.

2. The apparatus of claim 1 wherein said second member is a slip expander means that is adapted to shift a normally retracted slip means outwardly during movement in said one direction, said expander means being adapted to retract said slip during movement in said opposite direction.

3. The apparatus of claim 1 wherein said second member is a sleeve structure that is adapted for mounting a settable packing means, movement of sleeve structure in said one direction causing expansion of said packing means and movement thereof in the opposite direction enabling retraction of said packing means.

4. The apparatus of claim 1 wherein said lock member is constituted by a split ring having internal teeth that mesh with external teeth on said first member to provide said gripping engagement, said ring having external cam surfaces that are engaged by internal cam surfaces on said cam means.

5. The apparatus of claim 4 wherein said cam means is constituted by a split cam ring having the capability for lateral expansion and contraction between said one and said other position.

6. The apparatus of claim 5 wherein said holding means is constituted by an annular member having limited longitudinal movement with respect to said second member, said member having an internal annular looking surface that engages said cam ring in said one position, said member being movable longitudinally to dispose a relief means opposite said cam ring to enable movement thereof to said other position.

7. Apparatus for use in a well tool, comprising: a body member, an annular member surrounding said body member and movable relatively therealong; releasable one-way lock means for enabling movement of said annular member along said body member in one direction but normally preventing movement in the opposite direction, said lock means including an expansible and contractible ring having gripping engagement with said body member, cam means engaging said ring and said annular member and causing said ring to grip said body member when in one position and movable to another position to enable said ring to pass longitudinally therethrough; holding means for positioning said cam means in said one position and including means to enable movement of said cam means to said other position; and elongated recess means within said annular member sized to receive said ring after its passage through said cam means and during subsequent movement of said annular member along said body member in said opposite direction.

8. The apparatus of claim 7 wherein said ring has upwardly and outwardly inclined external cam surfaces and said cam means has downwardly and inwardly inclined internal cam surfaces, said cam surfaces being slidably engaged when said cam means is in said one position and disengaged when said cam means is in said other position.

9. The apparatus of claim 8 wherein said cam means and said annular member have oppositely facing transverse surfaces that are engageable to transmit longitudinal forces from said annular member to said cam means in said opposite direction when said cam means is in said one position.

10. The apparatus of claim 9 wherein said elongated recess means is formed internally of annular member on a diameter at least as great as the outer diameter of said ring.

11. The apparatus of claim 10 wherein said cam means is formed by the lower end portion of a sleeve having a plurality of circumferentially spaced slots cut from the lower end thereof to divide said lower end portion into a plurality of laterally flexible fingers, each finger having an enlarged head portion that is provided with said internal cam surfaces and one of said oppositely facing transverse surfaces.

12. The apparatus of claim 1 1 wherein the upper portion of said sleeve has internal threads therein adapted to be connected with latch means on a seal mandrel extending into said body member.

Claims

6. The apparatus of claim 5 wherein said holding means is constituted by an annular member having limited longitudinal movement with respect to said second member, said member having an internal annular locking surface that engages said cam ring in said one position, said member being movable longitudinally to dispose a relief means opposite said cam ring to enable movement thereof to said other position.

12. The apparatus of claim 11 wherein the upper portion of said sleeve has internal threads therein adapted to be connected with latch means on a seal mandrel extending into said body member.