U.S. patent application number 12/366793 was filed with the patent office on 2009-08-20 for on-site assemblable packer element for downwell packing system.
Invention is credited to Andreas Lutz, Peter Williamson.
Application Number | 20090205842 12/366793 |
Document ID | / |
Family ID | 40954055 |
Filed Date | 2009-08-20 |
United States Patent
Application |
20090205842 |
Kind Code |
A1 |
Williamson; Peter ; et
al. |
August 20, 2009 |
ON-SITE ASSEMBLABLE PACKER ELEMENT FOR DOWNWELL PACKING SYSTEM
Abstract
A packer system for a wellbore includes: a tubular member; a
packer element mounted on the tubular member and formed of a
swellable polymeric material; and a securing unit that is
configured to enable the position of the packer element to be
adjusted relative to the tubular member when the securing unit is
in an unsecured condition, but secures the packer element in place
when the securing unit is in a secured condition.
Inventors: |
Williamson; Peter;
(Schriesheim, DE) ; Lutz; Andreas; (Nideggen,
DE) |
Correspondence
Address: |
MYERS BIGEL SIBLEY & SAJOVEC
PO BOX 37428
RALEIGH
NC
27627
US
|
Family ID: |
40954055 |
Appl. No.: |
12/366793 |
Filed: |
February 6, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61028989 |
Feb 15, 2008 |
|
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Current U.S.
Class: |
166/387 ;
166/179 |
Current CPC
Class: |
E21B 33/1208
20130101 |
Class at
Publication: |
166/387 ;
166/179 |
International
Class: |
E21B 33/12 20060101
E21B033/12 |
Claims
1. A packer element unit for a packer system for a wellbore,
comprising: a generally annular packer element having an external
surface, the packer element being formed of a swellable polymeric
material; and a tightening band circumscribing the external surface
of the packer element, the tightening band being configured to
apply radially inward compression to the packer element to secure
the packer element on a tubular member.
2. The packer element unit defined in claim 1, wherein the
swellable polymeric material is a hydrocarbon-swellable
material.
3. The packer element unit defined in claim 2, wherein the
hydrocarbon-swellable polymer is selected from the group consisting
of: ethylene propylene rubber, ethylene-propylene-diene terpolymer
rubber, butadiene rubber, brominated butadiene rubber, chlorinated
butadiene rubber, chlorinated polyethylene, neoprene rubber,
styrene butadiene copolymer rubber, sulphonated polyethylene,
ethylene acrylate rubber, epichlorohydrin ethylene oxide copolymer,
silicone rubbers and fluorsilicone rubber.
4. The packer element unit defined in claim 1, wherein the
swellable polymer is a water-swellable polymer.
5. The packer element unit defined in claim 4, wherein the
water-swellable polymer is selected from the group consisting of:
starch-polyacrylate acid graft copolymers; polyvinyl alcohol cyclic
acid anhydride graft copolymers; isobutylene maleic anhydride;
acrylic acid type polymers, vinylacetate-acrylate copolymers;
polyethylene oxide polymers; carboxymethyl cellulose type polymers;
and starch-polyacrylonitrile graft copolymers.
6. A packer system for a wellbore, comprising: a tubular member;
and a packer element mounted on the tubular member and formed of a
swellable polymeric material; and a securing unit that is
configured to enable the position of the packer element to be
adjusted relative to the tubular member when the securing unit is
in an unsecured condition, but secures the packer element in place
when the securing unit is in a secured condition.
7. The packer system defined in claim 6, wherein the securing unit
comprises a tightening band that circumscribes the packer
element.
8. The packer system defined in claim 6, wherein the swellable
polymeric material is a hydrocarbon-swellable material.
9. The packer system defined in claim 8, wherein the
hydrocarbon-swellable polymer is selected from the group consisting
of: ethylene propylene rubber, ethylene-propylene-diene terpolymer
rubber, butadiene rubber, brominated butadiene rubber, chlorinated
butadiene rubber, chlorinated polyethylene, neoprene rubber,
styrene butadiene copolymer rubber, sulphonated polyethylene,
ethylene acrylate rubber, epichlorohydrin ethylene oxide copolymer,
silicone rubbers and fluorsilicone rubber.
10. The packer system defined in claim 6, wherein the swellable
polymer is a water-swellable polymer.
11. The packer system defined in claim 10, wherein the
water-swellable polymer is selected from the group consisting of:
starch-polyacrylate acid graft copolymers; polyvinyl alcohol cyclic
acid anhydride graft copolymers; isobutylene maleic anhydride;
acrylic acid type polymers, vinylacetate-acrylate copolymers;
polyethylene oxide polymers; carboxymethyl cellulose type polymers;
and starch-polyacrylonitrile graft copolymers.
12. A packer system for a wellbore, comprising: a tubular member;
and a packer element mounted on the tubular member and formed of a
swellable polymeric material; and a securing end cap configured
such that its position relative to the tubular member can be
adjusted and secured.
13. A method of deploying a packer system in a wellbore, comprising
the steps of: determining a desired level for a packer element
within a wellbore based on conditions in the wellbore; positioning
the packer element on a tubular member based on the determining
step; securing the packer element on the tubular member to form a
packer system; and positioning the packer system into the wellbore
such that the packer element is located at the desired level
determined in the determining step.
14. The method defined in claim 13, wherein the securing step
comprises tightening a tightening band that circumscribes the
packer element to compress the packer element onto the tubular
member.
15. The method defined in claim 13, wherein the securing step
comprises securing an end cap to the tubular member.
16. The method defined in claim 13, wherein the packer element
comprises a swellable polymer.
17. The method defined in claim 16, wherein the conditions in the
wellbore determined in the determining step include the level of a
liquid in the wellbore, and wherein the positioning step comprises
positioning the packer element so that it will contact the liquid
in the wellbore when the lowering step is performed.
18. The method defined in claim 17, wherein the swellable polymer
is a water-swellable polymer.
19. The method defined in claim 17, wherein the swellable polymer
is a hydrocarbon-swellable polymer.
Description
RELATED APPLICATION
[0001] The present application claims priority from U.S.
Provisional Patent Application No. 61/028,989, filed Feb. 15, 2008,
the disclosure of which is hereby incorporated herein in its
entirety.
FIELD OF THE INVENTION
[0002] The present invention relates generally to a wellbore system
for oil exploration, and more particularly to a packer for a
wellbore system.
BACKGROUND OF THE INVENTION
[0003] A downhole wellbore system typically includes a pipe or
other tubular structure that extends into a borehole drilled into
the ground. In some instances, a casing is inserted into the
wellbore to define its outer surface; in other instances, the rock
or soil itself serves as the wall of the wellbore.
[0004] Many wellbore systems include a packer, which is designed to
expand radially outwardly from the pipe against the walls of the
wellbore. The packer is intended to seal segments of the pipe
against the wellbore in order to isolate some sections of the
wellbore from others. For example, it may be desirable to isolate a
section of the formation that includes recoverable petroleum
product from an aquifer.
[0005] Known sealing members for packers include, for example,
mechanical packers which are arranged in the borehole to seal an
annular space between a wellbore casing and a production pipe
extending into the borehole. Such a packer is radially deformable
between a retracted position, in which the packer is lowered into
the borehole, and an expanded position, in which the packer forms a
seal. Activation of the packer can be by mechanical or hydraulic
means. One limitation of the applicability of such packers is that
the seal surfaces typically need to be well defined, and therefore
their use may be limited to wellbores with casings. Also, they can
be somewhat complicated and intricate in their construction and
operation. An exemplary mechanical packer arrangement is discussed
in U.S. Pat. No. 7,070,001 to Whanger et al., the disclosure of
which is hereby incorporated herein in its entirety.
[0006] Another type of annular seal member is formed by a layer of
cement arranged in an annular space between a wellbore casing and
the borehole wall. Although in general cement provides adequate
sealing capability, there are some inherent drawbacks such as
shrinking of the cement during hardening, which can result in
de-bonding of the cement sheath, or cracking of the cement layer
after hardening.
[0007] Additional annular seal members for packers have been formed
of swellable elastomers. These elastomers expand radially when
exposed to an activating liquid, such as water (often saline) or
hydrocarbon, that is present in the wellbore. Exemplary materials
that swell in hydrocarbons include ethylene propylene rubber (EPM
and EPDM), ethylene-propylene-diene terpolymer rubber (EPT), butyl
rubber, brominated butyl rubber, chlorinated butyl rubber),
chlorinated polyethylene, neoprene rubber, styrene butadiene
copolymer rubber (SBR), sulphonated polyethylene, ethylene acrylate
rubber, epichlorohydrin ethylene oxide copolymer, silicone rubbers
and fluorsilicone rubber. Exemplary materials that swell in water
include starch-polyacrylate acid graft copolymer, polyvinyl alcohol
cyclic acid anhydride graft copolymer, isobutylene maleic
anhydride, acrylic acid type polymers, vinylacetate-acrylate
copolymer, polyethylene oxide polymers, carboxymethyl cellulose
type polymers, starch-polyacrylonitrile graft copolymers and the
like and highly swelling clay minerals such as sodium bentonite.
Exemplary swellable packers are discussed in U.S. Pat. No.
7,059,415 to Bosma et al. and U.S. Patent Publication No.
2007/0056735 to Bosma et al., the disclosure of each of which is
hereby incorporated herein in its entirety.
[0008] Packer systems are typically assembled remotely from the
wellbore, i.e., the packer elements are fixed to the underlying
pipe or tube according to predetermined measurements. However, it
may be desirable to provide a packer system that allows on-site
adjustment of the positions of the packer elements on the pipe to
address variable conditions in the wellbore. It may also be
desirable to provide a system that enables the length of the packer
to be adjusted on-site.
SUMMARY OF THE INVENTION
[0009] As a first aspect, embodiments of the present invention are
directed to packer element units for wellbores. Such a packer
element unit comprises: a generally annular packer element having
an external surface, the packer element being formed of a swellable
polymeric material; and a tightening band circumscribing the
external surface of the packer element, the tightening band being
configured to apply radially inward compression to the packer
element to secure the packer element on a tubular member. In this
configuration, the location of the packer element relative to the
tubular member can be adjusted, particularly on-site of the
wellbore, to enable the packer system to be adjusted based on
conditions in the wellbore.
[0010] As a second aspect, embodiments of the present invention are
directed to a packer system, comprising: a tubular member; a packer
element mounted on the tubular member and formed of a swellable
polymeric material; and a securing unit that is configured to
enable the position of the packer element to be adjusted relative
to the tubular member when the securing unit is in an unsecured
condition, but secures the packer element in place when the
securing unit is in a secured condition.
[0011] As a third aspect, embodiments of the present invention are
directed to a packer system for a wellbore, comprising: a tubular
member; a packer element mounted on the tubular member and formed
of a swellable polymeric material; a securing end cap configured
such that its position relative to the tubular member can be
adjusted and secured. In this embodiment, the end cap can be
adjusted to position the packer elements at desired locations on
the tubular member.
[0012] As a fourth aspect, embodiments of the present invention are
directed to a method of assembling a packer system. The method
comprises the steps of: determining a desired level for a packer
element within a wellbore based on conditions in the wellbore;
positioning the packer element on a tubular member based on the
determining step; securing the packer element on the tubular member
to form a packer system; and positioning the packer system into the
wellbore such that the packer element is located at the desired
level determined in the determining step.
BRIEF DESCRIPTION OF THE FIGURES
[0013] FIG. 1 is a schematic side view of a packer system according
to embodiments of the present invention.
[0014] FIGS. 2-4 are schematic side views showing steps in the
assembly process of the packer system of FIG. 1.
[0015] FIG. 5 is an enlarged schematic side view of the packer
system of FIG. 1 showing a tightening ring installed on the endmost
packer element.
[0016] FIG. 6 is an enlarged schematic side view of a packer system
according to alternative embodiments of the present invention
showing an end cap installed adjacent the endmost packer
element.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0017] The present invention will now be described more fully
hereinafter, in which preferred embodiments of the invention are
shown. This invention may, however, be embodied in different forms
and should not be construed as limited to the embodiments set forth
herein. Rather, these embodiments are provided so that this
disclosure will be thorough and complete, and will fully convey the
scope of the invention to those skilled in the art. In the
drawings, like numbers refer to like elements throughout.
Thicknesses and dimensions of some components may be exaggerated
for clarity.
[0018] Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which this
invention belongs. It will be further understood that terms, such
as those defined in commonly used dictionaries, should be
interpreted as having a meaning that is consistent with their
meaning in the context of the relevant art and will not be
interpreted in an idealized or overly formal sense unless expressly
so defined herein.
[0019] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the invention. As used herein, the singular forms "a", "an" and
"the" are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood
that the terms "comprises" and/or "comprising," when used in this
specification, specify the presence of stated features, integers,
steps, operations, elements, and/or components, but do not preclude
the presence or addition of one or more other features, integers,
steps, operations, elements, components, and/or groups thereof. As
used herein the expression "and/or" includes any and all
combinations of one or more of the associated listed items.
[0020] In addition, spatially relative terms, such as "under",
"below", "lower", "over", "upper" and the like, may be used herein
for ease of description to describe one element or feature's
relationship to another element(s) or feature(s) as illustrated in
the figures. It will be understood that the spatially relative
terms are intended to encompass different orientations of the
device in use or operation in addition to the orientation depicted
in the figures. For example, if the device in the figures is turned
over, elements described as "under" or "beneath" other elements or
features would then be oriented "over" the other elements or
features. Thus, the exemplary term "under" can encompass both an
orientation of over and under. The device may be otherwise oriented
(rotated 90 degrees or at other orientations) and the spatially
relative descriptors used herein interpreted accordingly.
[0021] Well-known functions or constructions may not be described
in detail for brevity and/or clarity.
[0022] Turning now to the figure, a downwell pipe assembly,
designated broadly at 20, is shown in FIG. 1. The assembly 20 is
inserted into a wellbore, which is defined by walls in the earth.
In some embodiments the assembly 20 may be disposed within a casing
or other annular member that is inserted in the earth, or it may be
inserted directly into the earth. In addition, the wellbore may be
substantially vertically disposed, substantially horizontally
disposed or disposed at any angle typically used for wells. As used
herein, the term "wellbore" is intended to encompass any of these
scenarios.
[0023] A packer system 30 is mounted to a segment of a base pipe
22. The packer system 30 includes a plurality of annular packer
elements: in the illustrated embodiment, the system 30 includes a
center element 32, two intermediate elements 34 that sandwich the
center element 32, and two end elements 36 that sandwich the
intermediate elements 34. In the illustrated embodiment, the
elements 32, 34, 36 abut each other; however, in some embodiments
gaps may exist between some or all of the elements.
[0024] The elements 32, 34, 36 are formed of a material, typically
an elastomer, that swells when contacted with a swelling fluid.
Most common swelling fluids include water and hydrocarbons. The
elements 32, 34, 36 thus typically comprise materials that are
selected for their ability to swell when in contact with water or
hydrocarbon, depending on the projected location of the packer
system 30 within the wellbore 10. Exemplary elastomeric materials
that swell in hydrocarbons include ethylene propylene rubber (EPM
and EPDM), ethylene-propylene-diene terpolymer rubber (EPT), butyl
rubber, brominated butyl rubber, chlorinated butyl rubber),
chlorinated polyethylene, neoprene rubber, styrene butadiene
copolymer rubber (SBR), sulphonated polyethylene, ethylene acrylate
rubber, epichlorohydrin ethylene oxide copolymer, silicone rubbers
and fluorsilicone rubber. Exemplary elastomeric materials that
swell in water include starch-polyacrylate acid graft copolymer,
polyvinyl alcohol cyclic acid anhydride graft copolymer,
isobutylene maleic anhydride, acrylic acid type polymers,
vinylacetate-acrylate copolymer, polyethylene oxide polymers,
carboxymethyl cellulose type polymers, starch-polyacrylonitrile
graft copolymers and the like.
[0025] The swellable elastomer may also include fillers and
additives that enhance its manufacturing or performance properties
and/or reduce its costs. Exemplary filler materials include
inorganic oxides such as aluminum oxide (Al.sub.2O.sub.3), silicon
dioxide (SiO.sub.2), magnesium oxide (MgO), calcium oxide (CaO),
zinc oxide (ZnO) and titanium dioxide (TiO.sub.2), carbon black
(also known as furnace black), silicates such as clays, talc,
wollastonite (CaSiO.sub.3), magnesium silicate (MgSiO.sub.3),
anhydrous aluminum silicate, and feldspar (KAlSi.sub.3O.sub.8),
sulfates such as barium sulfate and calcium sulfate, metallic
powders such as aluminum, iron, copper, stainless steel, or nickel,
carbonates such as calcium carbonate (CaCo.sub.3) and magnesium
carbonate (MgCo.sub.3), mica, silica (natural, fumed, hydrated,
anhydrous or precipitated), and nitrides and carbides, such as
silicon carbide (SiC) and aluminum nitride (AlN). These fillers may
be present in virtually any form, such as powder, pellet, fiber or
sphere. Exemplary additives include polymerization initiators,
activators and accelerators, curing or vulcanizing agents,
plasticizers, heat stabilizers, antioxidants and antiozonants,
coupling agents, pigments, and the like, that can facilitate
processing and enhance physical properties.
[0026] The swelling elastomer may also include a swelling agent. In
some embodiments, the swelling agent may be a sorbent for
hydrocarbon. Also, in some embodiments the swelling agent may
comprise polyethylene (particularly linear polyethylene) and/or
other polymers, which may be combined with a hydrocarbon wax or the
like. Other suitable swelling agents include thermoplastic polymer
and copolymer mixtures and polyalphaolefins.
[0027] In some embodiments, the elements 32, 34, 36 may include a
protective coating that is removed once the system 30 is inserted
into the wellbore. The protective coating may be removed with a
fluid that is present in the wellbore, or may be removed through
the introduction of a non-naturally-occurring fluid or agent in the
wellbore.
[0028] The elements 32, 34, 36 are constructed so as to be able to
slide relative to the base pipe 22 when being inserted thereon (see
FIGS. 2-4). This can be achieved by making the central opening in
each of the elements slightly larger than the diameter of the pipe
22. As such, the elements 32, 34, 36 can be inserted onto the pipe
22 and moved relative thereto, which enables an operator to
position the elements precisely on the pipe 22. The ability to move
the elements 32, 34, 36 relative to the pipe 22 provides the
operator with the capacity to determine a desired level for the
packer elements 32, 34, 36 and to adjust the positions of the
elements 32, 34, 36 to the desired level and secure them at that
level, while on-site, to account for changing conditions in the
wellbore, mismeasurement, and the like.
[0029] Moreover, the length of the overall packer system 30 may be
adjusted on-site by including or omitting packer elements. For
example, if it is determined that the system 30 should be greater
in length than that provided by the five elements 32, 34, 36,
additional elements can be added to the pipe 22 on-site.
[0030] Installation of the elements 32, 34, 36 on the pipe 22 can
be understood from FIGS. 2-5. Starting with the base pipe 22 (FIG.
2), an endmost element 36 can be slid into position on the pipe
(FIG. 3). In the illustrated embodiment, the endmost element
includes a tightening ring 38 applied to an end portion of the
endmost element 36. The tightening ring 38 can be applied in
multiple ways. For example, it may be formed of a heat-shrinkable
material, or it may be a band that can by tightened through
mechanical means (e.g., a manual or pneumatic drive unit). With
either of these techniques, the tightening band 38 radially
compresses the element 36 to fix it in position on the base pipe 22
(FIG. 5). By fixing the positions of at least one endmost packer
element 36 (and in most instances both endmost elements 36), the
remaining elements can remain in position. Thus, additional
elements 32, 34, 36 can be added to the pip 22 (FIG. 4). Of course,
in other embodiments, all elements may be positioned on the pipe 22
prior to the securing of the endmost element 36. Also, other means
of securing the endmost element, such as mechanical fasteners,
adhesives or the like, may also be employed.
[0031] As another example for fixing the position of the elements
32, 34, 36 on the base pipe 22, as shown in FIG. 3, an end cap 40
can be fixed to the base pipe 22 to abut the endmost element 36.
The end cap 40 can be fixed by any number of fixing techniques,
including mechanical fasteners, adhesives, welding or the like. The
end caps 40 can, in some embodiments, have a diameter that is
slightly larger than the diameter of the elements 32, 34, 36 in
order to protect the elements as the system 30 is being inserted
into the wellbore. The end caps 40 may also be used in conjunction
with a tightening ring 38. Like the tightening ring, the end cap 40
can be converted between a secured condition, in which the end cap
40 is fixed to the pipe 22, and an unsecured condition, in which
the end cap 40 can moved relative to the pipe 22.
[0032] Those skilled in this art will appreciate that other
embodiments may also be suitable. For example, the packer system 30
may be thicker at its center than toward its ends. For example, it
may comprise multiple distinct elements of different diameters, a
single tapered element, or even a single element with a "stepped"
profile with sections of different diameters rather than being
tapered, in order to enable the center region of the packer system
to contact the walls of the wellbore prior to the end portions.
Also, if multiple distinct elements such as elements 32, 34, 36 are
employed, the materials of each may vary, often such that the
system includes central elements that swell more rapidly. Of
course, the numbers of elements may also vary depending on the
environment of use.
[0033] The foregoing is illustrative of the present invention and
is not to be construed as limiting thereof. Although exemplary
embodiments of this invention have been described, those skilled in
the art will readily appreciate that many modifications are
possible in the exemplary embodiments without materially departing
from the novel teachings and advantages of this invention.
Accordingly, all such modifications are intended to be included
within the scope of this invention.
* * * * *