Retrievable Well Packer

Abstract

A well packer is provided which may be permanently anchored in a well casing, but which may be retrieved without damage to either the casing or the packer. The packer may have separate upper and lower mandrel sections, and the upper cone is preferably collapsible but supported in an expanded condition by a support ring on the upper mandrel section when the packer is anchored. To retrieve the packer, the upper mandrel section is lifted from the lower mandrel section to draw the support ring from under the upper cone. When the upper cone collapses about the upper mandrel section, this disengages the upper slips from the casing. Further upward travel of the upper mandrel section draws the lower mandrel section and lower cone from under the lower slips and disengages them from the casing.

Description

BACKGROUND OF INVENTION

This invention relates to well packers and the like, and more particularly relates to permanently anchored packers which are adapted to be retrieved without damage to either the well or the packer.

There are many instances such as production operations wherein it is desirable to define and segregate one portion of a borehole from another. In those instances wherein the borehole is lined with a steel casing or the like, this is achieved by setting a packer assembly in the casing at such depth as may be desired.

In some instances, it may be desired that the well be "packed off" only temporarily, wherein in many other instances it is intended that the packer be permanently set in the well. So-called "temporary packers" are usually designed to be wedged in the casing in such manner as to resist movement in only one direction. This is because retrieval of a temporary packer is usually achieved by shifting in the opposite direction to disengage it from the interior of the casing. On the other hand, "permanent" packers are wedged in the casing in a manner opposing movement in either direction. Hence, most permanently anchored packers cannot be dislodged without damage to either the casing or the packer.

It is common occurrence for it to become desirable to remove a packer that has been permanently installed. Since this usually requires a drilling operation and consequent destruction of the packer, this may be quite costly. Moreover, it has become common to construct permanent packers of drillable materials so that they can be easily shattered by the drill bit. Although this provides a substantial saving insofar as drilling time is concerned, it has the disadvantage that a frangible packer may be an inherently weaker packer. Furthermore, the fragments and other debris from the shattered packer tend to clutter the bottom of the borehole, and may interfere with subsequent operations. In addition, a permanent packer is an expensive piece of equipment as such.

There have been many attempts to provide a packer which is adapted to be anchored immovably in the borehole, but which is also adapted to be retrieved whenever desired without damage to either the packer or the interior of the borehole or casing. However, none of these retrieval permanent packers have met with complete acceptance by the oil and gas industry.

In many cases, the packers have been both anchorable and retrievable, but either special setting techniques or equipment have been required to install the packer, or else special retrieval techniques and equipment have been necessary. In these cases, it has often cost more to retrieve such a packer then it would have cost to drill through and destroy it. Other packers such as that depicted in U.S. Pat. No. 3,398,795, have been capable of being installed and retrieved by special setting and removal equipment; however, such equipment and the packer itself are quite complicated and expensive.

These and other disadvantages of the prior art are completely overcome with the present invention, and novel packer means is provided herein which is adapted to be anchored immovably in a well casing or the like by conventional setting techniques, and which is also adapted to be selectively retrieved by conventional retrieval techniques and equipment without damage to either the packer assembly or the casing.

THE INVENTION

In a preferred embodiment of the invention, a packer assembly is provided which has a conventional elastic packing body located on the lower one of separate upper and lower mandrel sections which are arranged in end-to-end relationship to each other, but which may be connected together by a detachable link such as a shear pin or the like together with a collet finger assembly. An upper slip and expander assembly is mounted on the upper mandrel section and functions to anchor against upward movement, the assembly including a collapsible expander cone that is normally supported by a slidable support ring.

A lower slip and expander assembly of conventional design is mounted on the lower mandrel section and functions to anchor against downward movement. When the packer is set, the collet fingers are locked by engagement with a production tube or stinger so that the upper and lower mandrel sections are rigidly attached together.

During retrieval of the subject packing assembly, the collet fingers are left unsupported, and a retrieving tool is used to raise the upper mandrel section through the casing a limited distance from the lower mandrel section. Since the aforementioned support ring is slidably mounted on the upper mandrel section, the support ring will remain fixed beneath the upper cone to keep the upper slips wedged against the casing until the support ring is engaged by a snap ring or other suitable protrusion fixedly secured to the upper mandrel section. Further upward travel of the upper mandrel section away from the lower mandrel section will thus lift the support ring slidably upward and out from under the upper cone. The cone is thus permitted to collapse or contract about the upper mandrel section, thereby disengaging the upper slip from the casing.

The upper and lower mandrel sections are preferably linked together in some suitable manner such as by a pin and slot arrangement. Furthermore, the upper slip is arranged to be engaged in some suitable manner by upward movement of the upper mandrel section. Hence, when the upper mandrel section is lifted a sufficient distance, it will first engage and lift the upper slip completely free of the casing surface, and it will thereafter engage and carry the lower mandrel section upwardly. Upward travel of the lower mandrel section preferably first engages and draws the lower cone out from under the lower slips, and thereafter carries the lower slips and cone with it to the surface.

Accordingly, it is an object of the present invention to provide an improved packing assembly which is adapted to be immovably anchored in a casing or the like, and which is also retrievable without damage to or loss of any portion of the assembly and without damage to the casing.

It is further an object of the present invention to provide an improved packing assembly which is adapted to be immovably or permanently anchored in a casing or tubing by conventional setting techniques, and which is also adapted to be retrieved by conventional retrieval techniques and equipment without damage to or loss of any portion of the packing assembly and without damage to the casing.

These and other objects and features of the present invention will become apparent from the following detailed description, wherein reference is made to the figures in the accompanying drawings.

IN THE DRAWINGS

FIGS. 1A and 1B are pictorial representations, partly in cross section, of the upper and lower portions of a packer assembly which exemplifies the present invention, and which is disposed in a relaxed condition prior to being anchored in a casing or tubing.

FIG. 2 is a cross-sectional representation of a portion of the apparatus depicted in FIG. 1A.

FIGS. 3A and 3B are similar pictorial representations of the apparatus depicted in FIGS. 1A and 1B, respectively, wherein the depicted packing assembly has been anchored in the casing.

FIGS. 4A and 4B are also pictorial representations of the apparatus depicted in FIGS. 1A and 1B, respectively, wherein the illustrated packing assembly is shown in a disengaged condition for retrieval from the casing.

DETAILED DESCRIPTION

Referring now to FIGS. 1A and 1B, respectively, there may be seen pictorial representations, partly in cross section, of the upper and lower portions of a packing assembly such as a production packer longitudinally disposed in a casing 2, and relaxed prior to being anchored immovably in the casing 2. Accordingly, the depicted apparatus may be seen to include an upper mandrel section 3 having inside ratchet threads 4 located at its upper end, and having a suitable upper slip carrier 6 slidably mounted thereon with an inside annular shoulder 7 abutting the external surface of the upper mandrel section 3. A plurality of upper slips 9 of generally conventional design may be circumferentially arranged about the exterior surface of the upper mandrel section 3, and held together as an annular assembly by an expandable ring 10 or other suitable device. As further indicated, the slips 9 may each be loosely linked to the upper slip carrier 6 by means of a T-connection 8 or other suitable linking technique. A stepped support ring 13 is preferably slidably disposed about the upper mandrel section 3 beneath a suitable assembly of expander members 11 having an inside annular recess 34 adjacent their upper edges or "toes." Each slip 9 and respective cone segment 11 are preferably loosely linked together by a dovetail connection, or the like, and may also be temporarily fastened together by at least one shearpin 12 or other suitable means of frangible character.

The depicted assembly may include a lower mandrel section 14 arranged with its upper end encompassing the lower end of the upper mandrel section 3, and supporting the lower ends of the expander assembly 11. The upper and lower mandrel sections 3 and 14 may also be temporarily fastened together by a shear ring 18 or other suitable means of frangible character. In addition, the lower end of the upper mandrel section 3 may be provided with a plurality of collet fingers 20 each having an outwardly directed finger tip 21 for spring-loaded engagement with a suitable annular detent recess 22 in the lower end of the lower mandrel section 14.

As may be further seen in FIG. 1A, the upper mandrel section 3 is preferably provided with at least one longitudinal slot 5 for receiving and accommodating a pin 19 which is fixedly mounted in the upper end of the lower mandrel section 14. Accordingly, it will be noted that tip 21 is preferably omitted from the collet finger 20 which contains the slot 5. The reason for this is that the lower end of the slot 5 must engage the pin 19, when the upper mandrel section 3 is raised through the casing 2, in order for both mandrel sections 3 and 14 to be lifted out of the well during retrieval of the assembly. If this particular finger 20 is provided with a tip 21, the same as with the other fingers 20 in the lower end of the upper mandrel section 3, this particular tip 21 might cause this finger 20 to be forced inward, when the various tips 21 are pulled up and out of the detent recess 22, to an extent that the lower end of the slot 5 might pass up and over the pin 19 without catching it, when the upper mandrel section 3 is raised the maximum intended distance above the upper end of the lower mandrel section 14. If this occurs, the upper and lower portions of the illustrated packing assembly will become completely separated, and the lower portion will then fall to the bottom of the borehole.

Referring now to FIG. 1B, there may be seen to be one or more annular packing bodies 25 formed of an elastic material such as rubber or neoprene and disposed about the lower mandrel section 14 between upper and lower abutment rings 23 and 24, and immediately below the enlarged upper abutment portion 15 of the lower mandrel section 14. A suitable lower expander or cone 26 is preferably slidably mounted on the exterior surface of the lower mandrel section 14 immediately and abuttingly below these packing bodies 25, and is preferably temporarily secured to the upper end of a suitable plurality of lower slips 30 by means of one or more shearpins 29 or the like. The slips 30 are preferably of conventional design, and are circumferentially mounted about the lower end of the lower mandrel section 14, and secured thereto by an expandable ring 35 or other suitable means. A lower slip carrier 32 may be slidably disposed about the lower mandrel section 14, and may be loosely linked to the lower slips 30 by means of a T-connection 31 or other suitable means. The lower cone 26 may be provided with one or more splines 27 which are slidably engaged in one or more longitudinal grooves 28 in the lower mandrel section 14, and a retaining ring 33 is preferably fixedly mounted on the lower end of the lower mandrel section 14.

Referring to FIG. 2, there may be seen a cross-sectional representation of a portion of the apparatus depicted in FIG. 1, wherein the casing 2 is illustrated as containing a plurality of four cone segments 11 circumferentially and slidably disposed about the exterior surface of the support ring 13. As further indicated in FIG. 2, the support ring 13 may be seen to be slidably disposed between the exterior surface of the upper mandrel section 3 and the cone segments 11, when the depicted apparatus is in a relaxed condition prior to being anchored in the casing 2.

Installation of the assembly may be achieved in any one of many conventional modes, such as by a conventional setting tool which is suggested in FIGS. 1A and 1B by the compression member 37 and tension member 36 depicted therein. More particularly, the tension member 36 is conventionally disposed axially within the upper and lower mandrel sections 3 and 14, with a shear ring 38 for detachably coupling the lower end of the tension member 36 to the lower end of the lower slip carrier 32. The compression member 37 depicted in FIG. 1A may be seen to be any suitable device of conventional design for urging the upper slip carrier 6 downwardly against the upper slips 9. Thus, downward travel of the compression member 37 will shear the pins 12 and shift the upper slips 9 over the cone segments 11 and outwardly against the casing, whereupon the upper cone assembly 11 will be immovable within the casing 2.

After the upper slips 9 have been driven into fixed engagement with the interior surface of the casing 2, the upper and lower mandrel sections 3 and 14 are fixed and the tension member 36 will force the lower slip carrier 32 upwardly. This causes compression and expansion on the packing 25, and eventually the pins 29 will shear so that the slips 30 are shifted outwardly by the expander cone 26 into gripping contact with the casing 2.

After both the upper and lower slips 9 and 30 have been fixedly engaged with the interior surface of the casing 2, further upward tension on the tension member 36 will break the shearpin 38 and thereby disconnect the tension member 36 from the lower end of the slip carrier 32. The tension member 36 and compression member 37 may now be removed from the casing 2, and the packing assembly will now be anchored securedly in the casing 2 as depicted in FIGS. 3A and 3B. The installation of a production tube or stinger (not shown) having an outer diameter slightly less than the inner diameter of the upper mandrel section 3 will lock the collet heads 21 in engaged positions within the recess 22.

Referring to FIGS. 3A and 3B in particular, there may be seen a pictorial representation of the apparatus depicted in FIGS. 1A and 1B, respectively, wherein the tension member 36 and compression member 37 have been removed from the casing 2, and wherein the upper slip carrier 6 has been driven downwardly along the surface of the upper mandrel section 3 to urge the upper slips 9 downwardly and outwardly of the upper cones 11 and into fixed engagement with the inside surface of the casing 2. It will be noted that the shearpin 12 has been severed, as hereinbefore explained, but that the shear ring 18 connecting the upper and lower mandrel sections 3 and 14 is still intact. Further, the tips 21 of the collet finger 20 are presently positioned within the detent recess 22, and the pin 19 is located at the top of the slot 5, thereby indicating that the upper and lower mandrel sections 3 and 14 are positioned together as much as possible.

As may further be seen in FIG. 3B, the lower slip carrier 32 has now been disengaged from the lower end of the tension member 36 and driven slidably upwardly about the lower end of the lower mandrel section 14. This, in turn, has forced the lower slips 30 and cone 26 upwardly and compressively against the packing bodies 25 until the compression developed in the packing bodies 25 is sufficient to prevent further upward travel of the lower cone 26. Additional upward movement of the lower slips 30 and slip carrier 32 will then overcome and break the shearpin 29, and the lower slips 30 will then move upwardly and outwardly of the lower cone 26 until the slips 30 are fixedly wedged against the interior surface of the casing 2.

Referring now to FIGS. 4A and 4B, there may be seen pictorial representations of the apparatus depicted in FIGS. 1A and 1B, respectively, wherein a typical inside grapple-type retrieval tool 39 has been inserted or screwed into the threads 4 in the upper end of the upper mandrel section 3. The upper mandrel section 3 is upwardly movable independently of the upper slips 9 as well as the lower mandrel section 14. Accordingly, when the retrieval tool 39 is lifted through the casing 2, this will break the shear ring 18 and carry the upper mandrel section 3 upward and away from the lower mandrel section 14, until the lower end of the slot 5 catches the pin 19.

Upward movement of the upper mandrel section 3, however, will contract the springlike collet fingers 20 whereby the tips 21 can be shifted upwardly out of the detent recess 22. Thereafter, the upper mandrel section 3 will also travel upwardly independently of the lower mandrel section 14 until the pin 19 is engaged by the lower end of the slot 5 as hereinbefore stated, whereupon further upward movement of the upper mandrel 3 will also carry the lower mandrel section 14 upwardly through the casing 2.

It will be seen, however, that during upward movement of only the upper mandrel section 3 following disengagement of the tips 21 from the recess 22, the snap or shoulder ring 17 located in the recess 16 will first engage and lift the support ring 13 slidably out from under the cone segments 11, and that this ring 13 will be carried upward until it is deposited in the annular recess 34. This will permit the cone segments 11 to contract inwardly about the upper mandrel section 3, because of pressure from the upper slips 9 wedged against the casing 2. Accordingly, the upper slips 9 will be effectively released from the casing 2 as soon as the ring 13 is carried free of the cone segments 11, and the collapsible ring 10 will pull the upper slips 9 free of the inside surface of the casing 2 after the support ring 13 has been lifted from under the cone segments 11.

Further upward movement of the upper mandrel section 3 will carry the support ring 13 upwardly out of the annular recess 34 formed by the toes of the cone segments 11, and slidably past the upper slips 9, until the support ring 13 engages the lower edge of the inside annular shoulder 7 of the upper slip carrier 6. Thereafter, additional upward travel of the upper mandrel section 3 will carry the cone segments 11, slips 9, and carrier 6 as a unit through the casing 2, thereby preventing these components from being disconnected and lost in the well.

Disengagement of the upper slips 9 from the interior surface of the casing 2 will, of course, immediately release the compression being maintained in the packing bodies 25. Accordingly, the packing bodies 25 will expand longitudinally to lift the lower mandrel section 14 slightly upwardly through the casing 2, and to effectively release the pressure exerted by the lower cone 26 on the lower slips 30.

After the packing bodies 25 have expanded upwardly in the casing 2, as hereinbefore described, further upward travel of the upper mandrel section 3 will engage the pin 19 and thereafter carry the lower mandrel section 14 upwardly through the casing 2. As the lower mandrel section 14 is lifted through the casing 2, however, it will initially move slidably from under the lower slip carrier 32 and the lower slips 30. These components will not fall to the bottom of the casing 2, however, since the lower slip carrier 32 is preferably coupled to the lower slips 30 by means of a T-connection 31 or other suitable means, and since the lower slips 30 are preferably held together by a spring-like expansion ring 35 or other suitable device. Furthermore, the lower slips 30 are preferably loosely connected or linked to the lower cones or cone 26 by means of a dovetail connection or other suitable means.

When the lower mandrel section 14 has traveled a sufficient distance upwardly through the casing 2, however, the spline 27 of the lower cone 26 will be engaged by the retaining ring 33. Thereafter, the retaining ring 33 will carry the lower cone 26 upwardly through the casing 2 with the lower mandrel section 14. Although the packing bodies 25 may be slidably mounted on the lower mandrel section 14 as indicated in FIG. 4B, they will be supported about the lower mandrel section 14 by the lower cone 26. Furthermore, the lower cone 26 will carry the lower slips 30 and lower slip carrier 32 upwardly through the casing 2 to keep them from becoming separated from the packer assembly.

It will be apparent from the foregoing that many other variations and modifications may be made in the structures and methods described herein without substantially departing from the essential concept of the present invention. Accordingly, it should be clearly understood that the forms of the invention described herein and depicted in the accompanying drawings, are exemplary only and are not intended as limitations in the scope of the present invention.

Claims

What is claimed is:

1. A retrievable well packer assembly comprising

mandrel means having separate upper and lower sections longitudinally movable relative to each other,

an elastic packing body mounted on one of said sections of said mandrel means,

upper and lower slip means slidably respectively mounted on said sections of said mandrel means,

upper and lower expander means respectively slidably mounted on said sections of said mandrel means and respectively disposed between a slip means and one side of said packing body, said expander means on said other section of said mandrel means being laterally movable relative to said section between an outer position of supporting engagement with an adjacent slip means, and an inner position enabling inward movement of said adjacent slip means,

support means slidably disposed between said expander means on said other section of said mandrel means for maintaining such expander means responsive to longitudinal movement of said other mandrel section relative to said one mandrel section for removing said support means from between said expander means and said other section to enable inward movement of such expander means and an adjacent slip means.

2. A retrievable well packer assembly comprising

mandrel means having separate upper and lower sections longitudinally movable relative to each other,

an elastic packing body centrally mounted on said mandrel means,

upper slip means slidably mounted on said upper section of said mandrel means,

lower slip means slidably mounted on said lower section of said mandrel means,

upper and lower expander means slidably mounted respectively on said upper section and said lower section of said mandrel means and respectively disposed between said packing body and one of said slip means, one of said expander means being contractable relative to said mandrel means between an outer position of supporting engagement with a respective one of said slip means, and an inner position enabling inward movement of said one slip means,

support means slidably disposed between one of said sections of said mandrel means and said one expander means for maintaining said one expander means in said outer position relative to said mandrel means, and means responsive to longitudinal movement of one of said mandrel sections relative to the other for removing said support means from between said mandrel means and one expander means so that upon removal of said support means said one expander means and said respective one of said slip means can move inwardly.

3. The packer assembly described in claim 2, wherein said support means is an annular body slidably disposed about said one of said mandrel sections, and

wherein said one expander means is longitudinally slotted to enable movement thereof between outer and inner positions.

4. The packer assembly described in claim 3, wherein said removing means includes a shoulder on one of said mandrel sections that is engageable with said support means upon longitudinal movement of said one mandrel section relative to the other of said mandrel sections.

5. The packer assembly described in claim 4, wherein said upper and lower sections of said mandrel means have cooperation means for limiting longitudinal movement of said sections relative to each other.

6. A retrievable well packer assembly comprising

mandrel means including separate elongated upper and lower mandrel members coaxially aligned and longitudinally movable relative to each other,

engaging means interconnecting said mandrel members and limiting separation thereof,

upper expander means slidably mounted on said upper mandrel member and having an upwardly directed tapering toe portion,

upper slip means slidably mounted on said upper mandrel member for downward wedged engagement between said toe portion and the inside surface of a well casing or the like, said upper expander means being radially movable relative to said upper mandrel member between an outer position of supporting engagement with said upper slip means, and an inner position enabling inward movement of said upper slip means,

lower expander means slidably mounted on said lower mandrel member and having a downwardly directed tapering toe portion,

lower slip means slidably mounted on said lower mandrel member for wedged engagement between said toe portion of said lower expander means and the inside surface of a well casing or the like,

an annular elastic packing body disposed about said mandrel means between said expander means,

support means slidably mounted on said upper mandrel member and disposed in supporting relation to said upper expander means to normally maintain said upper expander means in said outer position, and means responsive to longitudinal movement of said upper mandrel member relative to said lower mandrel member and to said upper slip and expander means for sliding said support means out from behind said upper expander means to enable inward movement of said upper expander means and said upper slip means.

7. The well packer assembly described in claim 6, wherein said support means is a ringlike member slidably disposed about and engageable by means on said upper mandrel member upon movement of said upper mandrel member relative to said lower mandrel member.

8. The well packer assembly described in claim 7, wherein said upper expander means is provided with an internal annular recess opening outwardly of said toe portion thereof for receiving and accommodating said ringlike member.

9. The well packer assembly described in claim 8, wherein said expander means on said one mandrel member is a segmented annular cone-like body with the segments thereof maintained in supporting engagement with said upper slip means by said ringlike member accommodated in said annular recess and contractable about said one mandrel member upon withdrawal of said ringlike member from said recess.

10. A retrievable well packer assembly comprising

an elongated lower mandrel member,

an elongated upper mandrel member coaxially aligned and longitudinally movable relative to said lower mandrel member,

coupling means limiting said longitudinal movement of said upper mandrel relative to said lower mandrel member,

upper slip means slidably mounted on said upper mandrel member,

collapsible upper expander means slidably mounted on said upper mandrel member and adapted to shift said upper slip means into gripping contact with a well casing and to release said upper slip means from gripping contact with a well casing, lower slip means slidably mounted on said lower mandrel member,

lower expander means slidably mounted on said lower mandrel means and adapted to shift said lower slip means into gripping contact with a well casing,

packing means disposed on one of said mandrel members between said upper and lower slip and expander means, and

means for collapsing said upper expander means to release said upper slip means from gripping contact with a well casing.

11. A well packer assembly for use in a well bore comprising

telescopically arranged tubular members movable between longitudinally spaced positions, said members having means for releasably latching said members in one of said positions,

packing means disposed on one of said members,

anchor means on said one member operable for gripping engagement with the wall of a well bore and for providing a support for said packing means,

anchor means on said other member operable for gripping engagement with the wall of a well bore and for providing a support for said packing means, said anchor means on said other member including contractable expander means, and support means normally maintaining said expander means in an operable condition,

said anchor means when in engagement with the wall of a well bore preventing release of a compressed packing means, and

means on said other member engageable with said support means when said members are moved from said one position toward said other position for displacing said support means longitudinally of said contractable expander means to place said expander means in an inoperable condition.