U.S. patent application number 12/100127 was filed with the patent office on 2009-10-15 for multi-piece packing element containment system.
This patent application is currently assigned to Baker Hughes Incorporated. Invention is credited to Gary L. Anderson, Nicholas S. Conner.
Application Number | 20090255690 12/100127 |
Document ID | / |
Family ID | 41163037 |
Filed Date | 2009-10-15 |
United States Patent
Application |
20090255690 |
Kind Code |
A1 |
Conner; Nicholas S. ; et
al. |
October 15, 2009 |
Multi-Piece Packing Element Containment System
Abstract
Methods and devices for retaining a packer element in a set
condition within a wellbore and for preventing or minimizing
extrusion of the packer element after setting. A packer device
includes a plurality of deformable packer elements which radially
surround a packer mandrel. One or more of the packer elements is
contained against axial extrusion using a packer containment
system. The packer containment system includes a flexible metal
backup ring, which partially encases the packer element by
substantially covering at least one axial side and a portion of the
exterior radial surface of the packer element. The packer
containment system also includes a plurality of annular support
rings, or "petal rings" which have petal-shaped radial
protuberances with slots between them.
Inventors: |
Conner; Nicholas S.;
(Cypress, TX) ; Anderson; Gary L.; (Houston,
TX) |
Correspondence
Address: |
SHAWN HUNTER
P.O Box 270110
HOUSTON
TX
77277-0110
US
|
Assignee: |
Baker Hughes Incorporated
Houston
TX
|
Family ID: |
41163037 |
Appl. No.: |
12/100127 |
Filed: |
April 9, 2008 |
Current U.S.
Class: |
166/387 ;
166/195 |
Current CPC
Class: |
E21B 33/1216
20130101 |
Class at
Publication: |
166/387 ;
166/195 |
International
Class: |
E21B 33/128 20060101
E21B033/128 |
Claims
1. A containment assembly for a packer element in a packer device
comprising: a backup ring which partially encases the packer
element; and a plurality of support rings adjacent the backup ring
to prevent deformation of the backup ring.
2. The containment assembly of claim 1 wherein each of the support
rings comprises an annular petal ring having a plurality of
radially outwardly projecting petals that are separated by a
plurality of slots.
3. The containment assembly of claim 2 wherein the support rings
are radially offset from each other such that the petals of one of
the plurality of rings covers the slots of an adjoining ring.
4. The containment assembly of claim 1 wherein: the backup ring
comprises: a web portion that abuts an axial side surface of the
packer element; and a leg portion that overlies a radial outer
surface of the packer element.
5. The containment assembly of claim 1 wherein each of the support
rings presents a cross-sectional, substantially flat plate-form
annular body that is disposed angularly outwardly with respect to
the ring's axis.
6. The containment assembly of claim 5 wherein the body of the ring
is disposed angularly outwardly with respect to the ring's axis at
an angle that is from about 35.degree. to about 45.degree..
7. The containment assembly of claim 6 wherein the angle is about
40.degree..
8. The containment assembly of claim 1 wherein there are three
support rings.
9. The containment assembly of claim 1 wherein the backup ring is
substantially comprised of a malleable metal.
10. The containment assembly of claim 5 wherein each of the support
rings is deformed during a packer setting operation such that the
angular outward disposition of the ring body becomes approximately
90.degree..
11. The containment assembly of claim 10 wherein the support rings
do not contact an interior radial surface of a surrounding tubular
member when in a set condition.
12. A packer device for forming a fluid seal within a wellbore,
comprising: a central packer mandrel; a deformable packer element
radially surrounding the mandrel, the packer element being axially
compressible between an unset position wherein the element has a
radially reduced condition, and a set position wherein the element
has a radially expanded condition to form a fluid seal against a
surrounding surface; a setting sleeve that is moveable axially with
respect to the mandrel for selectively axially compressing the
packer element into its set position; a packer element containment
system to limit axial deformation of the packer element, the
containment system comprising: a) a backup ring which partially
encases the packer element; and b) a plurality of support rings
adjacent the backup ring to prevent deformation of the backup
ring.
13. The packer device of claim 12 wherein each of the support rings
comprises an annular petal ring having a plurality of radially
outwardly projecting petals that are separated by a plurality of
slots.
14. The packer device of claim 13 wherein the support rings are
radially offset from each other such that the petals of one of the
plurality of rings covers the slots of an adjoining ring.
15. The packer device of claim 12 wherein each of the support rings
presents a cross-sectional, substantially flat plate-form annular
body that is disposed angularly outwardly with respect to the
ring's axis.
16. The packer device of claim 15 wherein each of the support rings
is deformed when the setting sleeve is moved axially to set the
packer element, such that the angular outward disposition of the
ring body becomes approximately 90.degree..
17. The packer device of claim 12 wherein there are three support
rings.
18. The packer device of claim 12 wherein the backup ring is
substantially comprised of a malleable metal.
19. The packer device of claim 12 wherein the support rings do not
contact an interior radial surface of a surrounding tubular member
when in a set condition.
20. A method of containing a packer element against axial
extrusion, the method comprising the steps of: a) assembling a
packer device having: a central packer mandrel; a deformable packer
element radially surrounding the mandrel, the packer element being
axially compressible between an unset position wherein the element
has a radially reduced condition, and a set position wherein the
element has a radially expanded condition to form a fluid seal
against a surrounding surface; a setting sleeve that is moveable
axially with respect to the mandrel for selectively axially
compressing the packer element into its set position; a packer
element containment system to limit axial deformation of the packer
element, the containment system comprising a backup ring which
partially encases the packer element; and a plurality of generally
conically-shaped support rings adjacent the backup ring to prevent
deformation of the backup ring; b) moving the setting sleeve
axially with respect to the packer mandrel to compress the packer
element to its set position; and c) axially flattening the support
rings to form an axial structural barrier against extrusion of the
packer element.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates generally to packer devices used
within a wellbore.
[0003] 2. Description of the Related Art
[0004] Packers are used to create a fluid seal within a wellbore
between a central work string, such as a production tubing string,
and a surrounding tubular, such as a wellbore wall. A common packer
design has a central mandrel with an elastomeric packer element
surrounding the mandrel. The packer element is set by axially
compressing it on the mandrel. As the packer element is compressed
axially, the packer element is expanded radially outwardly and into
contact with the surrounding surface.
[0005] One problem with packer devices of this type is that of
extrusion of the packer element axially along the space between the
packer mandrel and the surrounding wellbore. This can occur as a
result of high wellbore temperatures, pressures and/or caustic
chemicals which act upon the packer element. Severe extrusion of
the packer element can cause the seal to fail.
SUMMARY OF THE INVENTION
[0006] The invention provides methods and devices for containing a
packer element in a set condition within a wellbore and for
preventing or minimizing extrusion of the packer element after
setting. An exemplary packer device is described which includes a
plurality of deformable packer elements which radially surround a
packer mandrel. One or more of the packer elements is contained
against axial extrusion using a packer containment system. In a
preferred embodiment, the packer containment system includes a
flexible metal backup ring, which partially encases the packer
element by substantially covering at least one axial side and a
portion of the exterior radial surface of the packer element. The
packer containment system also includes a plurality of annular
support rings, or "petal rings" which have petal-shaped radial
protuberances with slots between them. The petal rings are arranged
so that the petals of adjacent rings are radially offset. As a
result, the slots of each ring are covered by a petal of an
adjacent ring. Petal rings are preferred since they may be axially
compressed with relatively small amount of force due to the
presence of the slots. Because there are multiple support rings
used, a strong containment barrier is provided when set which
prevents extrusion of a packer element axially along the annular
space between the packer device and the inner surface of the
surrounding tubular member.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The advantages and further aspects of the invention will be
readily appreciated by those of ordinary skill in the art as the
same becomes better understood by reference to the following
detailed description when considered in conjunction with the
accompanying drawings in which like reference characters designate
like or similar elements throughout the several figures of the
drawing and wherein:
[0008] FIG. 1 is a side, partial cross-sectional view of an
exemplary packer assembly in accordance with the present
invention.
[0009] FIG. 2 is an enlarged cross-sectional view of a packer
element containment system in accordance with the present
invention.
[0010] FIG. 3 is an enlarged cross-sectional view of the
containment system shown in FIG. 2, now in a set condition.
[0011] FIG. 4 is an external isometric view of the containment
system shown in FIGS. 2-3, in an unset condition.
[0012] FIG. 5 is an external isometric view of the containment
system shown in FIGS. 2-3, in a set condition.
[0013] FIG. 6 is an axial external view of an exemplary petal-type
support ring used in the containment system shown in FIGS. 2-5.
[0014] FIG. 7 is an external isometric view of the exemplary
support ring shown in FIG. 6.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] FIG. 1 illustrates an exemplary packer assembly 10 which
includes a central packer mandrel 12. The packer mandrel 12 can be
incorporated into a production tubing string or other work string
(not shown), in a manner known in the art. A flowbore 14 is defined
within the mandrel 12. The outer radial surface of the mandrel 12
has an expanded diameter portion 16 which presents a stop shoulder
18. Radially surrounding the packer mandrel 12 and immediately
below the stop shoulder 18 is a packer element portion, generally
indicated at 20, the structure of which will be described in
greater detail shortly. A setting sleeve 22 radially surrounds the
packer mandrel 12 below the packer element portion 20. The setting
sleeve 22 is axially moveable with respect to the mandrel 12 and
presents a compression end 24.
[0016] The exemplary packer element portion 20 depicted in FIG. 1
includes an upper end cone 28 which surrounds the mandrel 12 and
abuts the stop shoulder 18. The packer element portion 20 also
includes an upper packer element 30 and an upper packer element
containment assembly 32. A first spacer ring 34 separates the upper
packer element 30 from a central packer element 36. A second spacer
ring 38 separates the central packer element 36 from a lower packer
element 40 and a lower packer element containment assembly 42. A
lower end cone 44 lies adjacent the containment assembly 42 and
abuts the compression end 24 of the setting sleeve 22.
[0017] It is noted that the upper packer element 30, central packer
element 36 and lower packer element 40 are preferably formed of
nitrile or another suitable elastomeric material. It is noted that
the packer elements 30, 36, 40 and spacer rings 34, 38, containment
assemblies 32, 42 and end rings 28, 44 are not affixed to the
mandrel 12 so that they may slide axially with respect to it. It is
noted that, during the initial construction and run in of the
packer assembly 10, the end rings 28, 44 are preferably affixed in
place using frangible shear screws, as is known in the art
[0018] FIGS. 2 and 3 depict the upper packer element containment
assembly 32 in greater detail. It is noted that the lower packer
element containment assembly 42 preferably has the same structure
and function as upper containment assembly 32. The upper
containment assembly 32 includes a solid backup ring 46 which is
substantially formed of a malleable metal of low yield and high
ductility. The backup ring 46 includes a close-fitting radially
reduced inner annular flange portion 48. A portion of the inner
flange portion 48 is disposed beneath an axially-extending lip 50
of the end cone 28. An annular web portion 52 of the backup ring 46
extends radially outwardly from the flange portion 48. The web
portion 52 lies axially adjacent the upper packer element 30. A leg
portion 54 extends axially along the outer radial surface 56 of the
packer element 30. The upper packer element 30 is partially encased
by the web portion 52 and the leg portion 54. In particular, the
web portion 52 and leg portion 54 of the backup ring 46 help
prevent axial extrusion of the element 30 axially toward the end
ring 28.
[0019] Support rings 58, 60, 62 are located adjacent to the backup
ring 46 and are preferably in an abutting relation to the backup
ring 46. The support rings 58, 60, 62 are preferably each
petal-type rings or, "petal rings" with a construction
substantially as follows. FIGS. 6 and 7 illustrate a single
exemplary petal ring 58 apart from the other components of the
containment assembly 32 and 42. It is noted, however, that the
exemplary construction shown for the petal ring 58 can be
representative of the same construction for rings 60, 62 as well as
each of the rings used in the containment assembly 42. The ring 58
has a cross-sectional, substantially flat plate-form annular body
64 that is disposed angularly outwardly with respect to the ring's
axis 66 at an angle 68, which is depicted graphically in FIG. 7.
Thus, the ring 58 has a generally conical form. The angle 68 may
vary depending upon the particular project and design in which the
assembly 10 will be used. Preferably, however, the angle 68 is from
about 35.degree. to about 45.degree.. Most preferably, the angle 68
is about 40.degree.. The body 64 of the ring 58 includes a
plurality of slots 70 which partially divide portions of the body
64 into petal portions 72. The presence of the slots 70 permits the
ring 58 to be deformed or bent more easily during the setting
process. The petal rings 58, 60, 62 are preferably formed of metal
and most preferably formed of a malleable metal with low yield and
high ductility.
[0020] In the embodiment of the containment assembly 32 depicted in
FIGS. 2-5, there are three petal rings 58, 60, 62. However, there
may be fewer than or more than three rings, as desired. A greater
number of rings will result in a higher containment force for the
packer element 30. When assembled, the petals 72 of adjacent rings
58, 60, 62 are offset from one another, as depicted in FIG. 4 so
that a petal 72 of one ring will overlap and cover the slot 70 of
an adjacent ring. This will help form a solid barrier against
extrusion by blocking the gaps provided by the slots 70.
[0021] In operation, the packer assembly 10 is set by moving the
setting sleeve 22 axially with respect to the mandrel 12 so that
the compression end 24 is urged against the end cone 44. This
results in the components 42, 40, 38, 36, 34, 32, 30 and 28 being
compressed against the stop shoulder 18. The setting sleeve 22 may
be actuated by one of any number of methods known in the art,
including the use of a setting tool (not shown) or hydraulically.
As the components are compressed, the packer elements 30, 36, and
40 are expanded radially outwardly as FIG. 3 shows, so that the
packer elements 30, 36, 40 are set against the external wall 80 of
a surrounding tubular.
[0022] When the packer assembly 10 is set in the manner described,
the upper and lower packer element containment assemblies 32,42
become actuated to prevent axial extrusion of the upper and lower
packer elements 30, 40, respectively. FIGS. 2 and 3 illustrate the
operation of the containment assembly 32 moving from unset (FIG. 2)
to set (FIG. 3) positions. The web and leg portions 52, 54 portions
of the backup ring 46 will flex, so that they remain in an encasing
relation to the packer element 30 and physically block potential
extrusion of the element 30 axially toward the end cone 28. In
addition, the petal rings 58, 60, 62 are compressed axially to the
conditions depicted in FIGS. 3 and 5. The slots 70 of the rings 58,
60, 62 are expanded, allowing the rings to be axially flattened.
When axially flattened, the angle 68 of the rings 58, 60, 62 is
increased to approximately 90.degree. (see FIG. 3). The support
rings 58, 60, 62 do not, themselves, necessarily contact the
surrounding surface 80 (see FIG. 3) when in the set position. The
support rings 58, 60, 62 form a structural axial barrier to help
preserve containment of the packer element 30 by preventing the
backup ring 46 from deforming, which might permit extrusion of the
packer element 30. The containment assemblies 32, 42 require a
relatively small amount of setting force is required, but provide
increased resistance to shear forces.
[0023] The foregoing description is directed to particular
embodiments of the present invention for the purpose of
illustration and explanation. It will be apparent, however, to
those skilled in the art that many modifications and changes to the
embodiment set forth above are possible without departing from the
scope and the spirit of the invention.
* * * * *