Note: Descriptions are shown in the official language in which they were submitted.
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Expandable Composite Tubulars
FIELD OF THE INVENTION
[0001] The field of this invention relates to tubulars that are expanded
downhole and more particularly to composite tubulars that can be expanded
wherein
the expansion triggers a polymerization reaction to lend rigidity to the
expanded
tubular or the reaction is otherwise triggered independent of the expansion.
BACKGROUND OF THE INVENTION
[0002] Expanding metallic tubulars downhole has become more common.
Casing, slotted liners and screens have been expanded using a variety of
techniques
involving fluid pressure or a swage. The expansion of tubulars has to date
excluded
the use of composites. Composites offer advantages of light weight, good
chemical
and thermal resistance properties, and low cost. The problem with composites
and
other non-metallics is that they are too brittle to withstand significant
expansions that
would make them useful in a downhole application where expansion was
contemplated when used in the finished form in which such tubular goods are
currently available.
[0003] Attempts to use composites in the past were in applications that were
not readily adapted for downhole use for a variety of reasons. A good example
is U.S.
Patent 4,752,431. In this reference, the tubular is provided in a limp
condition and
unrolled. It comprises a sandwich of a cement layer between two layers that
could be
flexible plastic, rubber or canvas. When water or steam is circulated, the
limp tubular
assumes a cylindrical shape and the cement sets to provide rigidity. The
application of
this technology is for lining existing pipes such as those that cross under
roads.
Another stated advantage is that the limp pipe can follow the contour of the
land and
then be hardened when pressurized with water.
[0004] U.S. Patent 5,634,743 uses a flexible lining that contains a curable
synthetic resin in conjunction with a device advanced with the lining to apply
ultrasonic energy to the leading end of the lining, as the lining is unfurled
along the
center of the pipe to be lined. Expansion is not contemplated in this process.
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[0005] U.S. Patent 5,925,409 shows a multi step procedure where a resin
containing hydrogen is reacted with a polycarbodiimide to make a tube that can
be
inserted into another tube for the purpose of lining it. The inner tube is
inflated to
contact the outer tube and then cured in place with hot air or water,
electricity or
radiation. The liner tube is inflated as opposed to expanded. A similar
concept is
employed in German Application DE 3732694 Al.
[0006] U.S. Application U.S. 2001/0010781 Al. involves putting cables in a
strip and then inflating a liner over the strip. The final step is to set the
body with hot
water in the liner or heat from cables that run through the body.
[0007] In WO 93/15131 a technique for lining sewer pipes and the like is
illustrated where the liner is applied followed by the application of
ultrasonic energy
to liberate microencapsulated catalyst. Alternatively, iron oxide particles
are
incorporated in the resin and are caused to heat by applying electromagnetic
energy.
No expansion is contemplated. Related to this technique are U.S. Patents
4,064,211;
4,680,066; 4,770,562.
[0008] Elastic Memory Composites and their ability to be deformed on
heating and to hold the deformed shape on subsequent cooling, have been
described in
a paper published by IEEE in 2001 entitled Developments in Elastic Memory
Composite Materials for Spacecraft Deployable Structures. These materials
resume
their original shape when reheated. More recently, R&D Magazine published in
the
July 2002 issue on page 13, an article describing the ability of a composite
tube to fix
stress cracks that form by liberation of an encapsulated compound as a result
of the
crack formation. Shape memory materials and some of their uses are described
in an
article by Liang, Rogers and Malafeew entitled Investigation of Shape Memory
Polymers and their Hybrid Composites which appeared in the April 1997 edition
of
the Journal of Intelligent Materials Systems and Structures. Also of interest
is
American Institute of Aeronautics and Astronautics paper 2001-1418 entitled
Some
Micromechanics Considerations of the Folding of Rigidizable Composite
Materials.
[0009] The object of this invention is to employ non-traditional materials for
well tubulars by taking advantage of their properties to allow the tubular to
be rapidly
deployed into a wellbore and then expanded in place. The expansion can trigger
a
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reaction that will harden the tubular in place to allow it to function
downhole.
Alternatively, the reaction can be otherwise triggered and the tubular
expanded.
Additionally, healing agents can also be encapsulated in the tubular to heal
subsequently forming cracks that may develop during the service life of the
expanded tubular. While composites that are flexible until a reaction occurs
are
envisioned as the preferred material, other materials are envisioned that
preferably
can be coiled with the catalyst encapsulated and that become rigid on
expansion with
the liberation of the catalyst. These and other advantages of the present
invention
will become more apparent to those skilled in the art from a review of the
description
of the preferred embodiment and claims, below.
SUMMARY OF THE INVENTION
[0010] Composite tubulars that have not been polymerized and are thus
flexible enough to be coiled are delivered into a wellbore and expanded. The
expansion occurs from an external catalyst such as heat or releases the
internal
catalyst and allows the expanded tubular to become rigid. Alternatively, the
reaction
can be triggered independently of the expansion. Optionally, healing agents
can be
imbedded in the tubular wall to be released to seal subsequently forming
cracks.
[0010a] Accordingly, in one aspect of the present invention there is provided
a method of installing a tubular string defined by a wall in a wellbore, the
string
capable of being put into an initial cylindrical dimension, comprising:
installing the tubular string into position in the wellbore while the
tubular string is in a flexible to the touch condition;
expanding the tubular string beyond the initial cylindrical dimension;
and
making the wall more rigid as a direct result of said expanding.
[0010b] According to another aspect of the present invention there is provided
a method of installing a tubular string defined by a wall in a wellbore, the
tubular
string capable of being put into an initial cylindrical dimension, comprising:
installing the tubular string into position in the wellbore while the
tubular string is in a flexible to the touch condition;
expanding the tubular string beyond said initial cylindrical
dimension;
making said wall more rigid as a direct result of said expanding; and
inflating the tubular after positioning it in the wellbore to point short
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of expansion.
[0010c] According to yet another aspect of the present invention there is
provided a method of installing a tubular string defined by a wall in a
wellbore, said
tubular string capable of being put into an initial cylindrical dimension,
comprising:
installing the tubular string into position in the wellbore while the
tubular string is in a flexible to the touch condition;
expanding the tubular string beyond said initial cylindrical
dimension;
making said wall more rigid as a direct result of said expanding; and
unrolling the tubular string from a coil prior to insertion into the
wellbore.
[0010d] According to yet another aspect of the present invention there is
provided a method of installing a tubular string defined by a wall in a
wellbore, said
tubular string capable of being put into an initial cylindrical dimension,
comprising:
installing the tubular string into position in the wellbore while the
tubular string is in a flexible to the touch condition;
expanding the tubular string beyond said initial cylindrical
dimension;
making said wall more rigid as a direct result of said expanding; and
providing a healing agent for sealing cracks in the wall of said
tubular string.
[0010e] According to still yet another aspect of the present invention there
is
provided a method of installing a tubular string defined by a wall in a
wellbore, said
tubular string capable of being put into an initial cylindrical dimension,
comprising:
installing the tubular string into position in the wellbore while the
tubular string is in a flexible to the touch condition:
expanding the tubular string beyond said initial cylindrical
dimension;
making said wall more rigid as a direct result of said expanding;
making said tubular string from a non-metallic material;
storing a catalyst for a hardening reaction in the wall of said tubular
string;
making the tubular string from a composite epoxy resin and a fiber
material;
providing a healing agent for sealing cracks in the wall of said
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tubular string; and
liberating said healing agent as a result of crack formation in the wall
of said tubular string in the vicinity of where said healing agent is stored.
[0010f] According to still yet another aspect of the present invention there
is
provided a method of installing a tubular string defined by a wall in a
wellbore, said
tubular string capable of being put into an initial cylindrical dimension,
comprising:
installing the tubular string into position in the wellbore while the
tubular string is in a flexible to the touch condition;
expanding the tubular string beyond said initial cylindrical
dimension; making said wall more rigid as a direct result of said expanding;
making said tubular string from a non-metallic material;
storing a catalyst for a hardening reaction in the wall of said tubular
string;
making the tubular string from a composite epoxy resin and a fiber
material; and
performing said expanding without cracking the wall of said tubular
string.
BRIEF DESCRIPTION OF THE DRAWINGS
[00111 Figure 1 is a schematic representation of the wall of the tubular
showing the catalyst that can be released on expansion and healing agent that
can
subsequently be released to fill stress cracks;
[0012] Figure 2 is a schematic view of the tubing fed into a wellbore off of a
reel prior to expansion;
[0013] Figure 3 is the view of Figure 2 shown after the tubing is expanded
and made rigid from the expansion; and
[0014] Figure 4 shows release of the catalyst occurring independently of
expansion with a swage as the swage is advanced.
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[00151 Figure I shows a schematic representation of a wall of a tubular that
is
preferably a composite epoxy resin system composed of a fiber material 10 and
further featuring encapsulated catalysts and hardeners 12 that are liberated
when the
tubular 14 is placed downhole as shown in Figure 2 and then expanded by any
one of
a variety of known techniques such as by a swage 16.It should be noted that
the
tubular that is initially in a flexible state can be reshaped to its original
dimension
without being expanded in the context used herein. Expansion is an increase in
size
above the original dimension when in the flexible state, regardless of the
manner such
increase in dimension is accomplished. After expansion, the encapsulated
catalyst is
liberated and a hardening reaction takes place. Alternatively, the reaction
can be
instigated by a mechanism independent of the expansion or the two events can
occur
contemporaneously. For example, an energy source such as electro-magnetic,
acoustic, or nuclear can be secured to an advancing swage where the source
triggers
the reaction in the tubular by permitting the catalyst to operate to trigger
the reaction
and the swage 16 expands the tubular. In that instance, the two events would
occur
contemporaneously rather than one triggering the other. This mode of operation
is
shown in Figure 4. The formerly limp tubular, that can optionally be lined
with a
metallic sacrificial inner sleeve 18 comes off a reel 20 and can be rapidly
deployed
downhole. It can advance due to its weight or it can have assistance in the
form of
known tools that employ anchors and a telescoping assembly to crawl downhole
taking with it the leading end 22 of the tubular 14. The tubular 14 can also
be partially
or fully inflated to its original maximum dimension for insertion but not
expanded.
When it is in position, it can be expanded to trigger the release of the
catalyst to begin
the hardening of the tubular 14. The catalyst and/or hardening agents can be
selected
for the expected temperatures and the desired final mechanical properties with
materials currently available from General Pacific Chemical. Optionally, a
healing
agent 24 can be encapsulated 26 in a manner that will retain the healing agent
even
despite prior expansion. Only a subsequently formed stress crack 28 will allow
the
healing agent 24 to flow into it to seal it up. The encapsulation 26 for the
healing
agent 24 will thus need to be severed or otherwise defeated. Simple expansion
of the
tubular 14 will release the catalyst 12 so that a reaction will commence with
the fiber
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reinforced epoxy material that forms the tubular 14. The liner 18 can remain
intact or
actually rip during the expansion. Optionally, liner 18 may be fully omitted.
[0016] The catalyst 12 can be tied up in the wall of the tubular in a physical
or
chemical way and can be liberated at the required time in a variety of
techniques. The
encapsulation of the catalyst can be defeated to trigger the desired hardening
reaction
by applying nuclear, magnetic, electric or electromagnetic energy or light
radiation or
the addition of or exposure to a chemical. Yet other ways include applied
force or
pressure or the introduction of a chemical to break the encapsulation for the
catalyst.
The catalyst can be selectively deposited to straddle the expected pay zones
so that in
the region of expected production the tubular will remain unhardened and could
permit production while above or below that zone the expanded tubular is
hardened to
preclude production or channeling between zones. The healing agent 24 can be
similarly distributed.
[0017] The fracture-healing feature is an adaptation of the process developed
at the University of Illinois, Champaign-Urbana and adapted to a tubular
structure for
downhole use.
[0018] Those skilled in the art will appreciate that the light weight and
corrosion resistance of composites are advantages in wellbore applications.
Previously, the brittle nature of fully formed composite tubes has precluded
their use
downhole, where expansion was contemplated. However, by delaying the
polymerization reaction the tubular 14 can be delivered to the desired
location and
expanded without the fear of cracking. The act of expansion triggers the
reactions to
allow the tubular to develop full strength. The expansion also allows the
tubular 14 to
conform to the shape of a surrounding tubular or the borehole, within limits,
before
the reaction bringing it to full strength commences.
[0019] Alternatively, the tubular 14 can be made of a shape memory material
that originally has a desired final diameter. The preformed material is heated
under an
applied force to alter its shape and then cooled to be able to advance it into
the
wellbore. After being advanced into the wellbore, the downhole temperature or
additional supplied heat causes the material to resume its original shape at
the desired
diameter downhole. This approach adapts a spacecraft application of such
materials to
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a tubular structure for downhole use. It should be noted that expansion is not
required
as the original tubular shape is already of the desired dimension, without
expansion.
However, to the extent that the elastic memory composite can withstand
expansion
forces, then some expansion can also be undertaken.
[0020] The foregoing disclosure and description of the invention are
illustrative and explanatory thereof, and various changes in the size, shape
and
materials, as well as in the details of the illustrated construction, may be
made without
departing from the spirit of the invention.
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