U.S. patent application number 12/134559 was filed with the patent office on 2009-06-04 for wrap-on reactive element barrier packer and method of creating same.
This patent application is currently assigned to Baker Hughes Incorporated. Invention is credited to Anthony P. Foster.
Application Number | 20090139708 12/134559 |
Document ID | / |
Family ID | 39744961 |
Filed Date | 2009-06-04 |
United States Patent
Application |
20090139708 |
Kind Code |
A1 |
Foster; Anthony P. |
June 4, 2009 |
Wrap-On Reactive Element Barrier Packer and Method of Creating
Same
Abstract
Systems and methods for installing an elastomeric element onto a
packer mandrel or other existing oil field tubular equipment. In
particular aspects, the packer device has a swellable elastomeric
packer element.
Inventors: |
Foster; Anthony P.; (Katy,
TX) |
Correspondence
Address: |
SHAWN HUNTER
P.O Box 270110
HOUSTON
TX
77277-0110
US
|
Assignee: |
Baker Hughes Incorporated
Houston
TX
|
Family ID: |
39744961 |
Appl. No.: |
12/134559 |
Filed: |
June 6, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60933471 |
Jun 6, 2007 |
|
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|
Current U.S.
Class: |
166/118 ;
156/191 |
Current CPC
Class: |
E21B 33/1208
20130101 |
Class at
Publication: |
166/118 ;
156/191 |
International
Class: |
E21B 33/12 20060101
E21B033/12; E21B 33/127 20060101 E21B033/127; B65H 81/08 20060101
B65H081/08 |
Claims
1. A method of forming a packer for a wellbore comprising the steps
of: disposing an uncured elastomer onto a curing mandrel, the
elastomer being swellable in response to contact with wellbore
fluids; curing the swellable elastomer; removing the cured
swellable elastomer from the curing mandrel; wrapping the cured
swellable elastomer onto a generally cylindrical packer
mandrel.
2. The method of claim 1 further comprising the step of securing
the swellable elastomer to the packer mandrel with a bonding
agent.
3. The method of claim 1 wherein the cured swellable elastomer is
wrapped onto the packer mandrel in a substantially helical
pattern.
4. The method of claim 1 wherein the step of removing the removing
the cured swellable elastomer from the curing mandrel comprises:
cutting through the cured elastomer in a substantially helical
pattern; and unwrapping the cut cured elastomer from the curing
mandrel.
5. The method of claim 2 further comprising the step of retaining
the cured elastomeric material upon the packer mandrel with a clamp
and allowing the bonding agent to set.
6. The method of claim 2 wherein the bonding agent comprises
epoxy.
7. The method of claim 2 wherein the bonding agent comprises molten
elastomer.
8. A method of assembling a packer device comprising: disposing a
section of uncured elastomer upon a packer mandrel, the elastomer
being swellable in response to wellbore fluids; and curing the
elastomer.
9. The method of claim 8 wherein the step of curing the elastomer
comprises wrapping the uncured elastomer with curing wraps.
10. The method of claim 8 wherein the step of curing the elastomer
comprises applying heat to the uncured elastomer from a heat
source.
11. The method of claim 10 wherein the heat source comprises a band
heater.
12. The method of claim 8 further comprising the step of securing
the elastomer to the packer mandrel with a bonding agent.
13. The method of claim 10 wherein the heat source is a mobile
molding unit.
14. A packer device comprising: a generally cylindrical packer
mandrel; and a cured strip of swellable elastomer deposited onto
the packer mandrel by wrapping.
15. The packer device of claim 14 wherein the swellable elastomer
is secured in place upon the packer mandrel by a bonding agent.
16. The packer device of claim 15 wherein the bonding agent
comprises epoxy.
17. The packer device of claim 15 wherein the bonding agent
comprises elastomer.
18. The packer device of claim 14 wherein the cured strip of
elastomer is wrapped onto the packer mandrel in a generally helical
pattern.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the priority of U.S. Provisional
Patent Application Ser. No. 60/933,471 filed Jun. 6, 2007.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to packer devices. In particular
aspects, the invention provides devices and methods for securing a
packer element to a packer mandrel.
[0004] 2. Description of the Related Art
[0005] Packers are used to create a fluid seal within a wellbore
between a tool string and the wellbore wall. Packer devices
incorporate elastomeric sealing elements that surround a central
mandrel. Particular variations of these packers are those that
employ elements that respond to the surrounding well fluids and
swell to form a seal. The packer device is incorporated into a
wellbore toolstring and disposed into the wellbore. When the packer
is to be set, the packer element is extruded or expanded radially,
as is known in the art, to contact and form a seal against the
wellbore wall.
[0006] In certain situations, there are problems with timely
delivery and cost associated with conventional packer elements
because of the limited number of manufacturers capable of making
the parts and delays associated with material procurement and
processes required to manufacture the conventional packers. One way
of mitigating manufacturing lead time and costs is to create
vulcanized or cured rubber sleeves that can be slid over a mandrel,
which, in this case, could be any existing oilfield tubular
equipment, and adhered directly. The inner diameter of the cured
sleeve is sized to form to the outer diameter of the mandrel, and
with a cured sleeve of the rubber element, the strength of the
rubber requires the assistance of machinery to allow the sleeve of
rubber to be slid over the end of the mandrel to the desired
position. The inventor has observed that a packer sealing or
barrier element formed of an elastomer that expands or swells upon
contact with wellbore fluids can be adhered directly to a mandrel
or other existing oil field tubular equipment without the use of
assisting machinery by wrapping a helically-cut, cured sleeve of
rubber around the desired position of the mandrel. If the element
is merely slipped onto the mandrel from an end, in the manner of a
continuous cylindrical sleeve, any adhesive can be wiped off,
possible resulting in a poor bond of the packer element to the
mandrel. Wrapping a helically cut sleeve over the area prepared
with adhesive would eliminate the wiping effect created by a solid
sleeve in addition to eliminating the need for assisting
machinery.
SUMMARY OF THE INVENTION
[0007] The invention provides systems and methods for installing an
elastomeric element onto a packer mandrel or other existing oil
field tubular equipment. In particular aspects, the invention
relates to the assembly of a packer device having a swellable
elastomeric packer element.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The structure and operation of the invention will be more
readily understood with reference to the following drawings, which
are illustrative thereof and among which like components are
numbered with like reference numerals:
[0009] FIG. 1 illustrates an exemplary curing mandrel having
elastomeric material applied to it.
[0010] FIG. 2 depicts removal of cured elastomer from the curing
mandrel.
[0011] FIG. 3 illustrates the operation of applying the cured
elastomer to a packer mandrel.
[0012] FIG. 4 illustrates an exemplary operation for disposing an
uncured elastomer upon a packer mandrel.
[0013] FIG. 5 depicts an exemplary technique for curing uncured
elastomer upon the packer mandrel using curing wraps.
[0014] FIG. 6 depicts that arrangement shown in FIG. 5 now with an
exemplary heating source applied.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] In accordance with an embodiment of the present invention,
uncured elastomer 10 is disposed onto a generally cylindrical
curing mandrel 12 of desired size, as illustrated in FIG. 1. These
rubbers or elastomers are of the type that will swell in response
to contact with fluids of the type found within a wellbore. No
bonding material is used between the curing mandrel 12 and the
elastomer 10. The elastomer 10 is then cured in place on the curing
mandrel 12 in a manner known in the art. Upon completion of curing,
the cured elastomer 10 is then removed from the curing mandrel 12.
In a preferred embodiment, the cured elastomer 10 is removed by
first cutting through the elastomer 10. It is further preferred
that the cuts 14 form a spiral or helical pattern so that the cured
elastomer that is to be removed is in a substantially helical
pattern. The elastomer 10 is then unwrapped from the curing mandrel
12 as indicated by the arrow 16 in FIG. 2.
[0016] The cured elastomer 10 is then applied and secured to the
outer radial surface of a generally cylindrical packer mandrel or
other tubular oilfield equipment 18, as depicted in FIG. 3. It is
noted that the packer mandrel 18 preferably has the same or similar
diameter to that of the curing mandrel 12 so that the elastomer 10
can be wrapped onto the packer mandrel 18, as in the direction
depicted by arrow 19 in FIG. 3, and form a complete and
substantially intact cylinder without discontinuities. Preferably,
a bonding agent is used to help bond the elastomer 10 to the packer
mandrel 18. In a currently preferred embodiment, the bonding agent
comprises a suitable epoxy. A heated liquid elastomer is preferably
also applied to the seams corresponding to the cuts 14 previously
made in the elastomer 10 to adhere the cuts/seams 14 together and
integrate the elastomer 10. The elastomer 10 is preferably then
retained in place upon the packer mandrel 18 using clamps or
similar means while the bonding agent sets and dries. Once the
bonding agent has adequately set and cured, the completed packer
device can be run into a wellbore in a manner that is known in the
art.
[0017] It is preferred to use the system and method of the present
invention with elastomers that are reactive or swell in response to
wellbore fluids. With packers that incorporate such reactive or
swellable elastomer, it is desired to have the packer element 10
secured to the packer mandrel 18 along substantially the entire
axial length of the packer element 10 and about the entire
circumference of the interface between the packer mandrel 18 and
the packer element 10. A barrier packer 20 is created that is
reactive to fluids within the wellbore.
[0018] In a variation of the system and method of the invention,
the elastomer 10 is put on a rubber mill and cut into long strips
or extruded into an uncured cylindrical pre-form 15 using a rubber
extruder and appropriately formed extruder die, as is known in the
art. A curing mandrel 12 is not needed for the application of
uncured rubber. For the case of uncured strips of rubber, the
elastomer 10 is wrapped around the desired area of the packer
mandrel 18, already prepared with an appropriate bonding agent in
the manner described for the mandrel 18 below. For the case of an
uncured, extruded cylindrical pre-form 15, the uncured pre-form 15
is placed onto the surface of the packer mandrel 18, as depicted in
FIG. 4. It is noted that the mandrel 18 has already been prepared
with an appropriate bonding agent in the same manner as for the
uncured rubber strips. For the case of the extruded cylindrical
pre-form 15, the interior diameter 20 of the pre-form would be
adequately large enough to permit the pre-form 15 to easily slide
over the pipe mandrel 18 to the approximate location prepared with
the bonding agent without wiping the bonding agent from the surface
of the mandrel 18.
[0019] Curing is then conducted upon the assembled packer assembly
22. One currently preferred method of curing the elastomer 15, as
illustrated in FIG. 5, is to wrap curing wraps 26 around the
uncured elastomer 15. Curing wraps 26 are usually a film or tape,
typically fashioned from nylon, with a significant shrinkage of
approximately 7% to 11% that occurs during the curing process. The
curing wraps 26 may be wrapped over the uncured elastomer 15 in an
overlapping spiral pattern known to those familiar with rubber
wrapping processes, although other suitable wrapping patterns may
be used. During curing of the elastomer 15, the curing wraps 26
shrink, which applies a significant radially-inward compressive
load to the elastomer 15 that is curing underneath. A heating
source, such as a band heater 28, of a type known in the art, is
then disposed over the curing wraps 26. FIG. 6 illustrates the
packer device 22 now disposed within an annular band heater 28 to
cause the elastomer 15 to be cured by applied heat. The band heater
28 is activated by a power source 30 to cure the elastomer 15. As
the uncured elastomer 15 heats up during the cure cycle, any spaces
or voids will knit together and close from the vulcanization. The
bonding agent will activate and begin bonding the curing elastomer
15 to the mandrel 18. The length of the curing cycle will be
determined by the thickness of the elastomer 15 being cured.
Generally, the curing process requires that the elastomer be
maintained at a temperature of about 300.degree. to about
320.degree. F. for around 1.5 hours. Heat may alternatively be
applied by any of a number of known heating sources, including, for
example, heating blankets similar to those used for annealing welds
on large pieces, as is known in the art. Alternatively, the
elastomer 10 may be cured using a specialized mobile molding unit,
of a type know to those of skill in the art. Where a mobile molding
unit is used for the curing lo process, curing wraps 26 are not
necessary to the curing process.
[0020] In a related aspect, the invention contemplates preparation
of the packer mandrel 18 prior to affixing the elastomer 10
thereto. The packer mandrel 18 is preferably prepared by
sandblasting, grinding, or buffing with sand paper or a similar
abrasive material to remove rust and scale from the outer radial
surface of the packer mandrel 18. It is then cleaned with a solvent
to remove oils and other chemicals. Then, a primer and bonding
agent for uncured rubber or an epoxy for the cured rubber is
applied to the area. Finally, the elastomer 10 is wrapped over the
mandrel 18 prior to curing. In the case of a cured piece of rubber,
the rubber is wrapped over the epoxy.
[0021] Those of skill in the art will recognize that numerous
modifications and changes may be made to the exemplary designs and
embodiments described herein and that the invention is limited only
by the claims that follow and any equivalents thereof.
* * * * *