Title:
Packing element and method
Kind Code:
A1


Abstract:
A packing element includes a mandrel, at least one seal member having a Chevron shape and composed of a metal material, and an energizer in operable communication with the at least one seal member and a method for packing a tubular.



Inventors:
Wright, Marie (Kintore, GB)
Simpson, Alan T. (Aberdeen, GB)
Application Number:
11/726265
Publication Date:
09/25/2008
Filing Date:
03/21/2007
Primary Class:
Other Classes:
166/118
International Classes:
E21B33/12
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Related US Applications:



Primary Examiner:
LOIKITH, CATHERINE A
Attorney, Agent or Firm:
CANTOR COLBURN LLP (Hartford, CT, US)
Claims:
1. A packing element comprising: a mandrel; at least one seal member having a Chevron shape and composed of a metal material; and an energizer in operable communication with the at least one seal member.

2. The packing element as claimed in claim 1 wherein the element further comprises at least one slip and at least one ramp in operable communication with the mandrel.

3. The packing element as claimed in claim 2 wherein the at least one ramp is movable on the mandrel.

4. The packing element as claimed in claim 2 wherein the at least one slip and at least one ramp is two slips and two ramps, one of each operable as a set and responsive to axial compression along the mandrel to increase an outside diameter of each slip and ramp combination.

5. The packing element as claimed in claim 1 wherein the at least one seal member comprises a stack of seal member elements.

6. The packing element as claimed in claim 1 wherein the at least one seal member is two seal members having a direction of the Chevron shape of each member opposed.

7. The packing element as claimed in claim 1 wherein the energizer is a resilient member.

8. The packing element as claimed in claim 1 wherein the energizer is a spring member.

9. The packing element as claimed in claim 1 wherein the at least one seal member when actuated creates a series of relatively narrow annular seals with a target tubular.

10. The packing element as claimed in claim 9 wherein the series of seals are at different relative diameters.

11. A method of packing a tubular comprising: compressing a packing element as claimed in claim 1; splaying open at least one seal member to enlarge a radial dimension of the member; and maintaining energy in the at least one seal member.

12. The method of packing a tubular as claimed in claim 11 wherein the compression is axial.

13. The method of packing a tubular as claimed in claim 11 wherein the splaying of at least one seal member is splaying open of a number of sealing elements to cause a number of relatively narrow annular seals to form against a target tubular.

14. The method of packing a tubular as claimed in claim 13 wherein the relatively narrow annular seals have different diameters.

15. The method of packing a tubular as claimed in claim 11 wherein the maintaining is by compressing an energizer to store energy that is automatically released upon a reduction in axial compression of the packing element.

16. The method of packing a tubular as claimed in claim 11 wherein the maintaining is by setting a ratcheting assembly.

17. The method of packing a tubular as claimed in claim 11 wherein the at least one seal member is a number of seal members, the members each including at least one sealing element.

18. The method of packing a tubular as claimed in claim 17 wherein the seal members are a mirror image of one another.

Description:

BACKGROUND OF THE INVENTION

Packing elements are well known and often used components of downhole operations. Packing elements are used for a number of different reasons in a number of different systems but generally all operate similarly. Packing elements are annular structures used to press against an inside or outside diameter of a target tubular, sometimes sealing thereagainst, to prevent all fluid communication past the packing element/tubular interface.

While the ubiquity of packing elements clearly evidences their effectiveness, it will be recognized by those of ordinary skill in the art that because of the elastomeric material utilized in most packing elements, degradation remains a problem for the art. The art is therefore always receptive to alternatives and especially those with greater robustness.

SUMMARY

A packing element includes a mandrel, at least one seal member having a Chevron shape and composed of a metal material, and an energizer in operable communication with the at least one seal member.

Further disclosed herein is a method of packing a tubular. The method includes compressing a packing element, splaying open at least one seal member to enlarge a radial dimension of the member, and maintaining energy in the at least one seal member.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the drawings wherein like elements are numbered alike in the several Figures:

FIG. 1 is a quarter section view of a packing element in accordance with this disclosure in the run in position;

FIG. 2 is a quarter section view of the element of FIG. 1 in the set position;

FIG. 3 is a quarter section view of an alternative arrangement of a packing element.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to FIG. 1, one embodiment of a packing element 10 that is in one iteration free of elastomeric members is illustrated in the run-in position. The element 10 includes a mandrel 12 upon which is disposed a series of components. The components include (arbitrarily starting from an uphole end of the packing element 10) a slip 14 in operable communication with a moveable ramp 16 disposed upon the mandrel; a release member 18 (such as a sheer screw) releasably attaching the moveable ramp 16 to the mandrel 12; a series (one or more sealing elements 20) of Chevron shaped seal members 22 disposed between the ramp 16 and an energizer 24; another series (one or more sealing elements) of Chevron shaped seal member 26 disposed between the energizer 24 and another moveable ramp 28; a release member 30 releasably attaching the ramp 28 to the mandrel 12; a slip 32 in operable communication with the ramp 28, and a ratchet assembly 34.

The packing element 10 is set to create a seal, by being axially compressed which causes a compression of each of the components numerically identified above to an axially smaller area. That is, in order to set the element 10, slip 14 is caused to reside more axially proximate to ratchet 34. This can be effected by preventing movement of ratchet 34 while moving mandrel 12 in a direction that brings a mandrel shoulder 36 closer to ratchet 34, thereby forcing all other components to also become closer to ratchet 34; by moving mandrel 12 in the same direction while moving ratchet 34 in an opposing direction; and by fixing the mandrel in place and moving the ratchet 34 toward mandrel shoulder 36. In each case, the axial distance between mandrel shoulder 36 and ratchet 34 is reduced thereby compressing all intermediary components into a smaller axial space. During such movement of the components hereof, the slips 14 and 32 are caused to move up ramp surfaces 38 and 40, respectively, thereby moving slips 14 and 32 radially outwardly of mandrel 12 into interfacing contact with an inside surface 42 of a tubular (not otherwise shown). Slips 14 and 32 thus provide anchoring of the packing element 10. The slips 14 and 32 are maintained in this position by ratchet assembly 34, which ratchets in the direction of compression of the packing element 10 and prevents movement in an opposite direction. Contemporaneously with the movement of slips 14 and 32, and as noted above, movable ramps 16 and 28 are also urged to move toward one another. In the illustrated embodiment, movement is unidirectional, though collectively converging. This can be noted from a review of FIG. 2 with specific attention focused upon release members 18 and 30, which are illustrated as shear members, in the sheared position. The converging relative movement of movable ramps 16 and 28 causes an axial load to be applied to seal members 22 and 26 as well as to energizer 24, positioned therebetween. In the compressed condition, the seal members 22 and 26 tend to yield to a configuration that is flatter, or alternatively stated, more radially directed than the condition in which they exist when at rest, (see FIGS. 1 and 2 in comparison). Due to the Chevron shape of each sealing element 20 of seal members 22 and 26, a flattening, i.e. a growth, or splaying open of an inside angle alpha, necessarily translates to an increasing radial distance between an inside edge 44 and an outside edge 46 of each sealing element 20 of each seal member 22 and 26. Radial growth is precisely what is needed to seal the annulus between mandrel 12 and inside diameter 42. In addition, because of the directional nature of the seal members 22 and 26, utilizing both directions in a single packing element 10 ensures that pressure is held from both directions.

Energizer 24, which is a resilient member such as a spring, ensures that sealing energy stays in the seal members even after multiple pressure reversals in the downhole environment. Such pressure reversals have been a cause of seal leakage and such is avoided in the context of the invention by employing the energizer 24.

In an alternate embodiment, referring to FIG. 3, the direction of the seal members 22 and 26 is reversed. Sealing is, however, effected in substantially the same way as the forgoing embodiment since the same forces are not at work to cause an enlargement of the angle alpha in the Chevron shaped members thereby increasing their radial dimensions.

In the foregoing embodiments, the seal members comprise non-elastomeric materials to enhance resistance of the packing element to downhole environmental conditions thereby ensuring a long, useful life of the element.

Because of the particular configuration of the sealing elements 20 of each seal member 22 and 26, a series of relatively narrow annular seal areas are created against both the inside surface 42 of a target tubular and the mandrel 12. This means that ridges and other surface irregularities of the target tubular are much more easily accommodated than with prior art packing elements having a broader contact surface in one element, where bridging might occur. For example, if a target tubular presents a series of annular irregularities, each of the individual sealing elements 20 of the seal members 22 and 26 will automatically adjust to the surface by extending more radially outwardly (limited of course to a maximum radial expansion related to total axial compression and the ability of the seals to flatten) or by being more highly loaded against a “high spot” on the casing so that the individual sealing element member does not expand radially to its otherwise fullest potential. Due to this property, the individual sealing element will create individual annular seals that together combine to create a more competent packing element while being exceptionally robust.

It is to be appreciated that while a pair of slips is shown and a pair of sealing members is shown, singles of each is also workable while still maintaining good sealing properties of the packing element. In such a configuration, the seal members 20 or even the energizer 24 could be arranged to abut the mandrel shoulder 36, for example, so that energy is storable in the packing element through axial compression thereof against the shoulder 36 or similar.

In yet another embodiment, where anchoring is not needed or desired, the seal members 22 (or 22 and 26) may be employed alone with such as ratchet assembly 34 to hold energy in the seals.

While preferred embodiments have been shown and described, modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation.