Retrievable Well Packer

Abstract

A well packer, which is provided with upper and lower slips and expanders for permanent anchoring in a casing, is also provided with retrieval means by which the slips may be disengaged without damage to either the packer or the casing. A special slotted retrieval sleeve or the like is provided for supporting the upper ends of a plurality of spacing bars wedged longitudinally between the elastic packing bodies and the upper expander. After the packer has been anchored, the sleeve may be lifted to remove the support provided to the upper ends of the bars, whereupon these ends of the bars will be driven loosely under the upper expander. The upper expander will thereafter not support the upper slip, and the packing bodies can relax to enable retrieval of the packer from the well.

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 or tubing. On the other hand, "permanent" packers are wedged in the casing in a manner opposing movement in either direction. Hence, permanently anchored packers of conventional design cannot be dislodged without damage either to the casing or to the packer, inasmuch as movement of the packer tends to jam the slips more firmly into engagement with the casing.

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 or 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 than 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, however, and novel packer means is provided herein which may be anchored immovably in a well casing or the like by conventional setting techniques, but which may also be adapted to be selectively retrieved by conventional retrieval techniques and equipment without damage to either the packer assembly or the casing.

SUMMARY OF INVENTION

In a preferred embodiment of the present invention, a well packer assembly is provided with one or more elastic annular packing bodies, and with upper and lower slip and slip-expanders for anchoring the packing bodies into locked fluidtight engagement with the inside surface of a casing in a generally conventional manner. However, the packer assembly is further provided with an assembly of spacing bars and a sleeve member of special configuration which may be engaged and raised to disengage the slips and expanders without significant damage to any portion of the packer assembly except for expendable shear pins and the like.

More particularly, the sleeve is provided with spaced-apart upper and lower longitudinal slots and is mounted at the upper end of the mandrel of the packer assembly. The upper slips are slidably mounted on the upper end of the special release sleeve, and further provided with splines or inwardly directed shoulder portions extending in the upper slots of the sleeve, whereby the sleeve may be moved upwardly between the upper slips and the mandrel while the slips are wedged between the casing and the upper expander. The upper expander is similarly provided with inwardly directed shoulder portions extending between the lower slots in the release sleeve, and a plurality of spacing bars are mounted longitudinally between the upper expander and the elastic bodies with their upper ends jammed against abutment surfaces on the lower expander and the release sleeve. The lower ends of the spacing bars are preferably wedged adjacent the surface of the mandrel, and thus the bars will be tilted upwardly and outwardly of the mandrel when the packer assembly is fully installed in the casing.

The upper end of the release sleeve is also preferably provided with inside ratchet threads or other suitable means for receiving and engaging the lower end of a grapple-type retrieving member. Accordingly, after the packing assembly has been "permanently" installed in a casing, it may be easily dislodged and removed by merely stabbing the retrieving member into the upper end of the sleeve, and by thereafter lifting the sleeve a limited distance sufficient to pull the lower end or edge of the sleeve from between the mandrel and the upper ends of the spacing bars.

The upper ends of the spacing bars are preferably canted downwardly and outwardly of the mandrel, the same as the edges of the upper expander against which the bars are jammed. As long as the lower edge of the sleeve is wedged between the mandrel and the upper ends of the spacing bars, however, the bars will remain wedged longitudinally between the elastic packing bodies and the upper expander.

On the other hand, when the sleeve is lifted free of the upper ends of the spacing bars, this removes their support, and the compressed packing bodies will relax sufficiently to drive the upper ends of the bars inwardly between the mandrel and the upper expander. This, in turn, completely releases the resistance to downward movement of the upper expander which upwardly wedges the upper slips against the inside surface of the casing. Accordingly, the sleeve may then be lifted a further distance sufficient to catch and lift the upper slips completely free of the upper expander without damage to either the expanders or the casing.

The foregoing action will, of course, permit complete upward relaxation of the elastic packing bodies and this, in turn, removes the downward pressure which jams the lower slips between the casing and the lower expander. Accordingly, the sleeve and upper slips may be interconnected such that sufficient upward travel of the sleeve will eventually engage and lift the packing assembly including the lower slips and expander out of the casing.

These and other features and advantages of the present invention will be apparent from the following detailed description wherein reference is made to the figures of the accompanying drawings.

IN THE DRAWINGS:

FIG. 1 is a pictorial representation, partly in cross section, of a packing assembly embodying the concept of the present invention and disposed for permanent installation in a well casing or the like.

FIG. 2 is a similar representation of the apparatus depicted in FIG. 1, illustrating the packing assembly after such installation.

FIG. 3 is also a similar representation of the apparatus depicted in FIGS. 1 and 2, but illustrating the details and relative position of its various components after the packing assembly has been released from the casing.

FIG. 4 is a pictorial representation of a preferred embodiment of the release sleeve hereinbefore described, and which is depicted in cross section in FIGS. 1-3.

FIG. 5 is a cross-sectional representation of a portion of the apparatus depicted in FIG. 1.

FIG. 6 is a cross-sectional representation of another portion of the apparatus depicted in FIG. 1.

FIG. 7 is a cross-sectional representation of a further different portion of the apparatus depicted in FIG. 1.

FIG. 8 is a cross-sectional representation of another different portion of the apparatus depicted in FIG. 1.

DETAILED DESCRIPTION

Referring now to FIG. 1, there may be seen a pictorial representation, partly in cross section, of a packing assembly disposed longitudinally in a well casing 2 or the like for permanent anchorage therein. In particular, the packing assembly may include a hollow tubular mandrel 11 having a special retrieval sleeve 9 slidably disposed about its upper end, and further having one or more elastic annular packing bodies 20 circumferentially mounted about its exterior below the sleeve 9. An expandable annular upper slip 13 may be slidably positioned about the upper end of the mandrel 11 below a plurality of spaced-apart shoulder extensions 12, and an upper expander 14 is preferably disposed about the mandrel 11 and sleeve 9 below the upper slip 13. A lower slip expander 23 may be mounted about the mandrel 11 below the packing bodies 20 and above an expandable lower slip 24. More particularly, the lower edge of the lower expander 23 may be wedged between the mandrel 11 and the lower slip 24, and may be secured thereto by a shear pin 25 or other suitable means. The lower end of the mandrel 11 may be provided with a conventional end collar 30, and a spring support collar 29 may be mounted above the end collar 30 and secured to the mandrel 11 by any suitable means such as a pin 28.

As may be further seen, the spring support collar 29 is provided with an interior annular cavity or recess for supporting a helical spring 26 having its upper end urged against a suitable spacer ring 32, or the like, positioned between the upper end of the spring support collar 29 and the lower abutting end of the lower slip 24. A stop ring 27 may be provided between the support collar 29 and the adjacent surface of the mandrel 11, which together with a stop ring 21 between the expander 23 and the mandrel prevent premature setting of the lower slip 24 and the packing 20 during running. An annular drive ring 22 may be located in an elongated recess about the mandrel 11 to limit upward and downward travel of the lower expander 23.

Referring again to FIG. 1, the apparatus preferably includes an annular abutment member 19 of conventional design mounted about the mandrel 11 immediately above the upper surface of the uppermost packing body 20. A plurality of rigid spacing bars 16 may be provided in groups at suitable locations about the exterior of the mandrel 11, and aligned between the upper expander 14 and the abutment member 19. More particularly, the lower ends of the spacing bars 19 may be seen to be seated adjacent the mandrel 11 in an annular internal recess in the abutment member 19 and may also be secured to the abutment member 19 by suitable pins 18 or the like. The upper ends of the spacing bars, however, are preferably wedged between the lower tapered edges of the downwardly extending fingers 35 of the retrieval sleeve 9 (see FIG. 4) and an internal annular recess in the upper expander 14. A suitable shear pin 17 or the like may be provided for linking the upper expander 1 to the sleeve 9.

The packing assembly as depicted in FIG. 1 may be anchored by a conventional setting tool 3 comprising a compressional member 5 (shown in phantom lines) arranged to be driven downwardly against the upper surface of the upper slip 13, and a tension member 4 for drawing the mandrel 11 upwardly in the casing 2. In particular, the tension member 4 may be composed of an elongated member or bar disposed within the mandrel 11 and having a locking rim 7 at its lower end. In addition, a collet ring having a plurality of collet fingers 8 may be slidably disposed about the lower end of the tension member 4 with the tips of the fingers 8 locked to the locking rim 7 by one or more shear pins 6 and extending below the lower end of the mandrel 11. Accordingly, the packing assembly depicted in FIG. 1 may be anchored in the casing 2 by simultaneously moving the compression member 5 downwardly through the casing 2 and drawing the tension member 4 upwardly therethrough. This will first cause the upper slip 13 to be shifted by the expander 14 into gripping engagement with the casing, whereupon the mandrel 11 will begin to travel upwardly. Upward movement of the mandrel 11 is transmitted by the drive ring 22 to the lower expander 23 which compresses and expands the packing 20 into sealing contact with the casing 2. During setting of the packing 20, the shear pins 25 will fail and enable the coil spring 26 to shift the slips 24 outwardly along the expander 23 and against the casing. The spring 26 continues to press the slips 24 into wedging engagement between the upper expander 14 and the casing 2.

When the upper and lower slips 13 and 24 and the packing 20 have been set forcefully against the casing 2, further upward movement of the tension member 4 will shear the pins 6, and will thereafter pull the locking rim 7 upwardly to free the tips of the collet fingers 8. The collet fingers 8 may then resile inwardly so that they may be drawn upwardly through the mandrel 11. Accordingly, the setting tool 3 may then be removed from the casing 2.

Referring now to FIGS. 4-8, there may be seen a pictorial representation of the special retrieval sleeve 9, and detailed cross-sectional representation of the related portions of the assembly at various locations. More particularly, the sleeve 9 may be seen in FIG. 4 to have a plurality of equally spaced-apart and aligned upper and lower extending fingers 37 and 35 respectively, which form upper and lower longitudinal slots 36 and 38. The upper ends of the fingers 37 may be seen to be provided with internal ratchet threads 10 to engage the end of a suitable retrieval tool, and the lower fingers 35 may be seen to be provided with tapered tips to slidably support the upper ends of the spacing bars 16 as hereinbefore described. The central annular or ringlike portions 34 of the sleeve 9 separates the upper and lower slots 36 and 38.

Referring again to FIG. 8, the upper beveled ends of the spacing bars 16 are wedged between the tapered surfaces of the lower fingers 35 and against the correspondingly beveled inner surface 39 of the upper expander 14. Referring now to FIG. 5, there may be seen a representation of the spaced-apart, shoulderlike extensions 12 which are located to ride between the upper fingers 37 of the sleeve 9, and further located to be engaged by the upper slip 13 when the slip 13 is carried upward along the mandrel 11 by the sleeve 9, as will hereinafter be explained.

Referring now to FIG. 2, there may be seen a pictorial representation, partly in cross section, of the packing assembly depicted in FIG. 1 after such assembly has been anchored in the casing 2. More particularly, the upper slip 13 has been driven downwardly along the interior surface of the expander 14 and into gripping engagement with the casing 2. Similarly, the lower expander 23 may be seen to have been driven upwardly against the packing bodies 20 to compress and expand them outwardly against the interior surface of the casing 2. In this respect, the lower slip 24 will also be seen to have been wedged between the lower expander 23 and the casing 2, after severing of the connecting shear pin 25. After the upper and lower slips 13 and 24 have been anchored, and after the setting tool 3 has been removed from the casing 2, the well packer will remain immovable in the casing until it is desired to remove it.

Referring now to FIG. 3, there may be seen a similar representation of the apparatus depicted in FIGS. 1 and 2, wherein a retrieval tool 40 has been stabbed into the upper end of the special retrieval sleeve 9 for the purpose of engaging the threads 10. Accordingly, when the retrieval tool 40 is drawn upwardly through the casing 2 a sufficient distance, the taper lower ends of the fingers 35 are first disconnected from the shear pin 17, and are thereafter drawn from under the upper ends of the outwardly directed spacing bars 16. After these tapered ends of the lower fingers 35 clear the upper ends of the spacing bars 16, decompression of the packing bodies 20 will drive the upper ends of the spacing bars 16 under the upper expander 14, and release the compression loading in the system.

The packing bodies 20 will completely relax to release the fluidtight engagement with the interior surface of the casing 2, and the upper expander 14 no longer supports the upper slip 13 with respect to the casing.

The retrieval tool 40 may now be further lifted through the casing 2 until the central annular portion 34 of the sleeve 9 engages the interior abutting portions 41 of the upper slip 13. Upward travel of the retrieval tool 40 will then cause the sleeve 9 to carry the upper slip 13 completely free of the casing 2, and from the upper part of the upper expander 14.

The packing bodies 20 may now be assumed to be fully relaxed and decompressed. However, the spring 26 may still be compressed sufficiently to drive the lower slip 24 upwardly into partial engagement between the casing 2 and the lower expander 23. Nevertheless, when the sleeve 9 has been raised sufficiently to drive the upper end of the upper slips 13 into abutting engagement with the lower side of the shoulders 12, this will cause the mandrel 11 to be lifted through the casing 2 and the stop ring 22 to lift the lower expander 23 out from underneath the lower slips 24. Then the entire assembly may be lifted free of the casing 2.

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 well packer apparatus comprising:

an elongated body member;

packing means on said body member adapted to be compressed and expanded into sealing contact with a well casing;

upper slip and expander means for anchoring against upward movement of said body member in said casing;

lower slip and expander means for anchoring against downward movement of said body member in said casing;

support means on said body member for maintaining said upper slip and expander means in fixed, spaced relation to said packing means and for maintaining said packing means in sealing contact with said casing; and

means for disabling said support means to enable the upper end portion of said packing means to move relatively toward said upper slip and expander means and to relieve said compression and expansion in said packing means.

2. The packer apparatus described in claim 1, wherein said disabling means includes

a sleeve means slidably mounted on said body member and upwardly movable relative to said packing means for disabling said support means.

3. The packer apparatus described in claim 2, wherein said support means is radially disposed about said body member between said sleeve member and said expander means for maintaining said compression and expansion in said packing means.

4. The packer apparatus described in claim 3, wherein said support means is radially disposed about said body member between said upper expander means and said packing means.

5. The packer apparatus described in claim 4, wherein said support means is radially collapsible about said body member upon upward movement of said sleeve member along said body member to release said upper expander means and said packing means.

6. A well packer apparatus comprising

a mandrel,

an annular body member formed of a resilient material and concentrically mounted on said mandrel,

upper expander means slidably mounted on said mandrel above said resilient body member,

lower expander means slidably mounted on said mandrel below said resilient body member,

upper slip means downwardly movable along said mandrel for wedging engagement between said upper expander means and the inside surface of a well casing or the like,

lower slip means upwardly movable along said mandrel for wedging engagement between said lower expander and the inside surface of a well casing or the like,

a sleeve means slidably movable on said mandrel independently of said expander means and said slip means and having one end extending at least partially between said upper expander and said mandrel, and

support means at least partially disposed between said upper expander means and the upper end of said body member for maintaining a spaced relationship therebetween.

7. The packer apparatus described in claim 6, wherein said support means comprises

a plurality of rigid members disposed about said mandrel and each having one end adjacent said resilient body member and the other end wedged between said upper expander means and said end of said sleeve member.

8. The packer apparatus described in claim 7, wherein said rigid members are elongated bar members longitudinally aligned with said mandrel.

9. The packer apparatus described in claim 8, wherein the ends of said bar members adjacent said upper expander means are adapted to be driven between said upper expander means and said mandrel by relaxation of said resilient body member upon withdrawal of said sleeve member from between said mandrel ans said upper expander means.

10. The packer apparatus described in claim 9, wherein said sleeve member is provided with a plurality of upper longitudinal slots extending partially along said sleeve member for accommodating said upper slip means, and

wherein said sleeve member is adapted to engage and draw said upper slip means out of wedging engagement between said upper expander means and said well casing after said end of said sleeve member is removed from between said ends of said bar members and said mandrel.

11. The packer apparatus described in claim 10, wherein said sleeve member is further provided with a plurality of lower longitudinal slots extending partially along said sleeve member for accommodating said upper expander means.

12. The packer apparatus described in claim 11, wherein said upper slip means is adapted to be slidably movable along said mandrel between said lower slots of said sleeve means.