Note: Descriptions are shown in the official language in which they were submitted.
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AXIAL COMPRESSION ENHANCED TUBULAR EXPANSION
BACKGROUND OF THE INVENTION
Field of the Invention
Embodiments of the invention generally relate to expanding tubulars in a
wellbore. More particularly, embodiments of the invention relate to the
expansion of the
tubulars enhanced by use of compressive forces applied to the tubulars.
Description of the Related Art
Hydrocarbon and other wells are completed by forming a borehole in the earth
and then lining the borehole with pipe or casing to form a wellbore. After a
section of
wellbore is formed by drilling, a section of casing is lowered into the
wellbore and
temporarily hung therein from the surface of the well. Using apparatus known
in the art,
the casing is cemented into the wellbore by circulating cement into the
annular area
defined between the outer wall of the casing and the borehole. The combination
of
cement and casing strengthens the wellbore and facilitates the isolation of
certain areas
of the formation behind the casing for the production of hydrocarbons.
Recent developments in the oil and gas exploration and extraction industries
have included using expandable bore lining tubing. Apparatus and methods are
emerging that permit tubulars to be expanded in situ. The most common
expansion
apparatus is a cone or a swedge. Some expansion apparatus include expander
tools
which are fluid powered and are run into the wellbore on a working string.
These
hydraulic expander tools can include radially extendable members which,
through fluid
pressure, are urged outward radially from the body of the expander tool and
into
contact with a tubular therearound. As sufficient pressure is generated on a
piston
surface behind these extendable members, the tubular being acted upon by the
expansion tool is expanded past its point of plastic deformation. In this
manner, the
inner and outer diameter of the tubular is increased in the wellbore. By
rotating the
expander tool in the wellbore and/or moving the expander tool axially in the
wellbore
with the extendable members actuated, a tubular can be expanded along a
predetermined length in a wellbore. Other methods include using hydraulic
pressure
inside the tubular to expand the tubular past its point of plastic
deformation.
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Multiple uses for expandable tubulars are being discovered. For example, an
intermediate string of casing can be hung off a string of surface casing by
expanding a
portion of the intermediate string into frictional contact with the lower
portion of surface
casing therearound. This allows for the hanging of a string of casing without
the need
for a separate slip assembly. Additional applications for the expansion of
downhole
tubulars exist. These include the use of an expandable sand screen, employment
of an
expandable seat for seating a diverter tool, and the use of an expandable seat
for
setting a packer.
There are problems associated with the expansion of tubulars. One particuiariy
associated with rotary expander tools is that the rotary expansion of the
tubular makes
the wall of the tubular thinner. This then increases the overall length of the
tubular
which is problematic when trying to determine location in the well. Further,
expandable
tubulars are currently limited to an expansion of 10%-25% of their original
diameter
using existing expansion techniques that are constrained by the tubular burst
pressure
and friction applied thereto. Also when using hydraulic pressure to expand the
tubular,
due to the high pressure required, weaknesses in the tubular are exploited
limiting the
amount of expansion that can be achieved before the tubular ruptures.
There exists a need for an improved method and apparatus for expanding casing
or other tubulars within a wellbore. Further, there exists a need for method
and
apparatus for expanding a tubular which requires less outward force or
hydraulic
pressure on the tubuiar with increased expansion. There exists yet a further
need for
an apparatus and method for expanding a tubular which reduces the risk of
uneven
expansion of the tubular by reducing the amount of force needed for the
expansion
operation. Further, there exists a need for a method of expanding a tubular
and
accurately controlling the location of the tubing.
SUMMARY OF THE INVENTION
Embodiments of the invention generally relate to methods and apparatus for
expanding tubulars in a wellbore enhanced by compressive force applied to the
tubulars. According to one aspect of the invention, a method of expanding a
tubular in
a wellbore includes positioning the tubular in the wellbore, affixing at least
two locations
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spaced along a length the tubular to desired locations in the wellbore, and
expanding a
portion of the tubular between the two locations outward radially with a
rotary expander
tool, such that the tubular is in compression while expanding. According to
another
aspect of the invention, methods and apparatus provide for expanding a tubular
run into
a wellbore by applying a compressive force to at least a portion of the
tubular and
applying fluid pressure to an inside surface of the tubular to expand the
tubular to a
larger diameter. The tubular can be located proximate to a window in the
wellbore such
that expanding the compressed portion of the tubular covers the window and may
form
a bulge extending through the window.
BRIEF DESCRIPTION OF THE DRAWINGS
So that the manner in which the above recited features of the present
invention
can be understood in detail, a more particular description of the invention,
briefly
summarized above, may be had by reference to embodiments thereof which are
illustrated in the appended drawings. It is to be noted, however, that the
appended
drawings illustrate only typical embodiments of this invention and are
therefore not to
be considered limiting of its scope, for the invention may admit to other
equally effective
embodiments.
Figure 1 is a sectional view of a wellbore having a tubular disposed therein
for
expansion according to aspects of the invention;
Figure 2 is a sectional view of a tubular and an expansion assembly attached
to
a work string and disposed in a wellbore;
Figure 3 is a sectional view of the tubular of Figure 2 after expansion with
hydraulic pressure applied to an inside surface thereof;
Figure 4 is a sectional view of the tubular of Figure 2 after completing
expansion
with hydraulic pressure;
Figure 5 is a sectional view of the tubular of Figure 4 after being expanded
in a
wellbore with a multilateral junction;
Figure 6 is a sectional view of the tubular of Figure 5 after being fully
expanded;
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Figure 7 is a sectional view of the multi-lateral junction of Figure 5
completed
with the tubular expanded and drilled out; and
Figures 8 to 11 are schematic illustrations of steps in the process of lining
a bore
in accordance with embodiments of the invention.
DETAILED DESCRIPTION
Figure 1 illustrates a cross-sectional view of a wellbore 100 and a tubular
110
disposed therein. The tubular 110 can be casing or any other type of tubular
used in
downhole drilling operations, such as a liner or a patch. First and second
fixed
locations 120, 130 spaced apart along the length of the tubular 110
substantially
prevent axial movement of the tubular 110 in the wellbore 100 such that the
distance
between the fixed locations 120, 130 cannot vary. The fixed locations 120, 130
can be
achieved by any method or combination of methods known in the art, such as by
using
anchors or slips on an outside of the tubular 110 to engage a surrounding
surface, by
selectively expanding the tubular 110 at one or both of the fixed locations
120, 130 into
frictional contact with the surrounding surface or by locating the bottom of
the tubular
110 on a stop such as a plug, a packer or a bottom of the borehole (see,
Figures 9-12).
In the embodiment shown in Figure 1, the fixed locations 120, 130 have been
expanded
to place the outside surface of the tubular 110 into contact with a
surrounding surface.
Expansion of the fixed locations 120, 130 can be performed by either using a
rotary
expander tool 140 or additional expander(s) (not shown), such as one or more
inflatable
members or packers, capable of selective expansion at the fixed locations 120,
130.
The fixed locations 120, 130 create an annular space between the tubular 110
and the
wellbore 100. To facilitate expansion of the tubular 110, fluid in the annular
space can
escape through apertures (not shown) in a surrounding casing and into a
formation,
through apertures in the tubular 110, across flow paths at one or both of the
fixed
locations 120, 130 such as by only partial circumferential expansion, and/or
directly into
the surrounding formation when in an open wellbore. For example, the tubular
110 may
serve as a patch to remedy excessive mud loss in an open hole such that fluid
from the
annular space can easily be pushed into the formation.
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U.S. Patent No. 6,457,532 discloses an exemplary rotary expander tool that can
be used as the rotary expander tool 140 schematically illustrated in Figure 1.
The
rotary expander tool 140 operates to expand the length of the tubular 110
between the
fixed locations 120, 130. Typically, the rotary expander tool 140 starts at
one fixed
location (e.g., the first fixed location 120) and progresses to the other
fixed location
(e.g., second fixed location 130) expanding the tubular 110 along the way. If
only one
location along the tubular is initially fixed, expansion can start a distance
from that
location to thereby provide the other fixed location prior to the rotary
expander tool 140
moving toward the initially fixed location. The tubular need not be placed in
compression prior to starting expansion of the tubular 110 between the two
fixed
locations 120, 130 since a compressive load in the tubular 110 develops as
expansion
with the rotary expander tool 140 progresses. This is due to the fact that use
of the
rotary expander tool 140 lengthens the tubular 110 by thinning of the tubular
wall which,
because the fixed locations 120 130 are set to prevent the elongation of the
tubular
110, compresses the tubular 110. In contrast, a cone used to expand a tubular
typically
causes the tubular to shorten during expansion such that tension and not
compression
develops if the cone is used to expand a section between two fixed locations.
The
compression in the tubular 110 enhances the expansion process by increasing
the
expansion possible and decreasing the amount of force required by the rotary
expander
too1140.
Before both of the two fixed locations 120, 130 are set, the tubular 110 can
optionally be placed in compression either through use of gravity or a
mechanical,
electrical, or hydraulic device adapted to apply a compressive load on the
tubular.
Since the tubular 110 is expanded between end points that are fixed, this
increases
accurate location of the tubular 110 in the wellbore 100. Thus, this process
enables
accurate placement of liners, patches and other tubulars in the wellbore
without the
side effects of having the liner elongate or shorten during expansion.
Figure 2 shows a section of the wellbore 100 with a liner 230 and expandable
tubing 200. The expandable tubing 200 can be casing, liner, a patch, or any
other type
of tubing used in downhole operations for expansion into the liner 230, casing
or an
open wellbore. Figure 2 depicts the expandable tubing 200 as a patch used for
closing
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an aperture 235 in the wellbore 100 that is lined. The patch can include a
seal 256 and
an anchoring element 257 on the outside of the expandable tubing 200.
The expandable tubing 200 attaches to a work string 210 via a setting tool
220.
The lower end of the expandable tubing 200 attaches to the work string 210 by
a
carrying mechanism 240 of the setting tool 220. The carrying mechanism 240 is
any
suitable temporary connection known in the art such as carrying dogs, collets,
threads,
latches, slips etc. In one embodiment the carrying mechanism 240 is a set of
pre-set
slips 231. The pre-set slips 231 engage the inside diameter of the expandable
tubing
200 with a series of teeth 232. The pre-set slips 231 support the weight of
the
expandable tubing 200 and the piston assembly. The pre-set slips 231 are held
in
place by wedges 233 and 234. Wedge 234 is fixedly attached to the work string
210.
Wedge 233 is attached to a slip release assembly 236. The slip release
assembly 236
connects to a seat 237. The seat 237 holds a sealing member such as a dart, or
ball
270 at its upper end in order to hydraulically seal the work string 210. The
seat 237
connects to the work string 210 with a shear pin 238. Above the pre-set slips
231 is a
lower pressure seal cup 239 for hydraulically sealing the interior of the
expandable
tubing 200. At the upper end of the expandable tubing 200, a compression
piston 250
of the setting tool 220 attaches the expandable tubing 200 to the work string
210. The
compression piston 250 has a shoulder 253 which engages the upper end of the
expandable tubing 200. The compression piston 250 moves relative to the work
string
210 and a piston base 251. The piston base 251 fixedly attaches to the work
sting 210,
thus as fluid flows in to an annulus 252, the piston 250 pushes the expandable
tubular
200 down relative to the work string 210. With the lower end of the expandable
tubular
200 fixed to the work string 210 by carrying mechanism 240, the expandable
tubular
200 is in compression. More than one compression piston can be used in order
to
increase the compressive force applied to the expandable tubing 200, as is
known in
the art. The carrying mechanism 240 and the compression piston 250 can be
adapted
to seal the top and bottom of the expandable tubing 200.
As illustrated in Figure 3, the work string 210 lowers into the wellbore 100
to a
desired location for the expandable tubing 200. Once at the desired location,
the
compression piston 250 actuates upon application of hydraulic pressure through
the
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work string 210, which can be selectively plugged by a stopper, such as a ball
270
dropped onto the seat 237, a diverter valve such as that disclosed in U.S.
Patent
Publication No. US 2006-0065408 assigned to Weatherford/Lamb, Inc. could also
be
used. The compression piston 250 urges the attached top of the expandable
tubing
200 toward the carrying mechanism 240. This places the expandable tubing 200
in
compression since the attachment of the top of the expandable tubing 200 via
the
compression piston 250 permits relative movement between the work string 210
and
the expandable tubing 200 while the attachment of the expandable tubing 200 at
the
carrying mechanism 240 prevents relative axial movement between the lower end
of
the expandable tubing and the work string 210. Simultaneously, hydraulic
pressure
provided through port 245 acts on an inside surface of the expandable tubing
200 to
cause radial expansion of the expandable tubing 200 along a length of the
expandable
tubing 200 between the lower pressure seal cup 239 and an upper pressure seal
cup
254.
The expandable tubing 200 can utilize changes in material and configuration in
order to enhance expansion. In one embodiment, the tubing thickness at the two
fixed
end points, the piston 250 and carrying mechanism 240 is larger that the
expandable
tubing 200 wall thickness between the fixed points. Further, in another
embodiment the
yield strength and/or elastic modulus of the expandable tubular 200 is changed
between the fixed points. In another embodiment the expandable tubular 200 is
longitudinally corrugated between the fixed points. In yet another embodiment
the
expandable tubular 200 has a different material than the material at the fixed
points.
Further, any of these methods can be used in combination to enhance expansion
of the
expandable tubular 200. These embodiments ensure the expandable tubular 200
expands from the middle portion first and then outwards toward both ends. This
ensures that fluids are not trapped in the annulus between the Expandable
tubular 200
and the liner 230.
After expansion of the expandable tubing 200 with hydraulic pressure it is
necessary to ensure the expandable tubular 200 is secure in the wellbore by
pulling or
pushing on the work string 210. The setting tool 220 then releases the
expandable
tubular 200 at the carrying mechanism 240. By increasing the hydraulic
pressure in the
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work string 210 the seat 237 shears the shear pin 238. This causes the slip
release
assembly 236 to move down which moves the lower wedge 233 down, releasing the
pre-set slips 231 as shown in Figure 4. Additionally, an expander 265 (shown
schematically) actuates to an extended position having an increased outer
diameter.
The expander 265 can be any type of expandable cone or hydraulically actuated
rotary
expander tool, such as those disclosed in U.S. Patent No. 6,457,532, U.S.
Patent No.
U.S. 7,121,351 and U.S. Patent Application Publication No. U.S. 2006-0065408.
Figure 4 shows the expandable tubing 200 while the expander 265 completes
expansion of the expandable tubing 200 along its entire length. In operation,
lowering
the work string 210 moves the expander 265 through the expanded section of the
expandable tubular 200 and across the end of the expandable tubular 200 where
expansion was previously prevented by the carrying mechanism 240. As the
expander
265 moves through the expandable tubular 200, the expander 265 insures proper
expansion and/or further expands the previously expanded length of the
expandable
tubular 200 and expands the bottom end of the expandable tubular 200.
Accordingly,
the previously unexpanded top end of the expandable tubular 200 where
expansion
was previously prevented due to attachment to the compression piston 250
occurs
upon pulling the expander 265 out of the expandable tubular 200 during removal
of the
work string 210. For some embodiments, the expander 265 may not be required if
it is
not desired to expand the ends of the expandable tubular 200 where the
expandable
tubular attaches to the setting tool 220. Further, the expander 265 can be
arranged to
work in conjunction the hydraulic expansion in order to enhance the expansion
process.
Further, the expander 265 can be attached either below or above the expandable
tubular 200 or on another tool and actuated once hydraulic expansion is
complete. The
work string 210 is removed upon completion of the expansion leaving the
expandable
tubing 200 in place. Thus, the expandable tubing 200 can be used to patch
apertures
in the casing, liner or the wellbore itself with no liner. In another
embodiment, the
unexpanded portions of the expandable tubular 200 could be removed by the
apparatus
and methods disclosed in U.S. Patent No. 6,598,678 assigned to
Weatherford/Lamb,
Inc. or as disclosed U.S. Patent No. 6,752,215 assigned to Weatherford/Lamb,
Inc.
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This procedure can be done multiple times in the wellbore in order to control
production
from the formations.
Figures 5-7 depict an embodiment of the invention that utilizes an assembly
similar to that illustrated in Figures 2-4. Figure 5 shows the wellbore 100
with a window
310 cut in the side to provide an opening for a lateral junction 320. An
expandable
tubing 300 is shown expanded so that it covers the lateral junction 320. The
expandable tubular 300 expands using the methods described above. Thus, the
expandable tubing 300 is compressed. While in compression, the expandable
tubing
300 is expanded by fluid pressure acting on an inside surface of the
expandable tubing
to initially expand the expandable tubing 300 up to an inner diameter of the
wellbore
100, as shown in Figure 5. The expansion process continues by further
application of
hydraulic pressure to cause a wall of the expandable tubing 300 to bulge at
the window
310 and enter the lateral junction 320, as shown in Figure 6. For enhanced
expansion,
the expandable tubing may comprise any suitable material which can sustain an
expansion ratio of greater than 20%. Further, the expandable tubing can be
initially
longitudinally corrugated in order to facilitate a high expansion ratio. The
expander 265
is removed from the wellbore. The lateral junction 320 can then be drilled out
using
techniques known in the art providing a multi-lateral junction, as shown in
Figure 7. A
subsequent liner (not shown) can be run into the lateral junction 320 and
suspended off
of the tubing 300 therein.
Figures 8-11 depict an embodiment of the invention used to line a wellbore
400.
Figure 8 shows the lower end of the wellbore 400 including an unlined bore
section
410. Above the unlined section 410, casing 420 lines the wellbore 400. As
shown, the
lower end of the casing 420 includes a larger diameter end section 425, or
bell-end,
however, the lower end of the casing 420 can be straight pipe.
An expandable tubing or liner 430 is run into the wellbore 400 on a work
string
440. The liner 430 is initially coupled to the work string 440 via a setting
tool 450. The
liner 430 is located in the wellbore 400 such that the upper end of the liner
430 overlaps
the larger diameter casing end section 425. The lower end of the liner 430 is
positioned
at the end of the wellbore 400. The liner 430 itself or a shoe 460 contacts
the bottom of
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the wellbore 400. Next, weight can optionally be set down on the liner 430.
The weight
can be from the length of the work string 440, or any other method that places
the liner
430 in a compressive state.
As shown in Figure 9, once the liner 430 is in compression, an anchor 470 is
set.
The anchor 470 can be any type of liner hanger known in the art. With the
anchor 470
set, the liner 430 is held in compression between the anchor 470 and the end
of the
wellbore 400. For some embodiments, the compressive state, as discussed above
with
regard to Figure 1, may be caused solely by the expansion process itself and
not
initially applied to the liner 430 prior to setting of the anchor 470.
Next, as shown in Figure 10, a rotary expander tool 480 moves downwardly
through the liner 430 to expand the liner 430 to a larger diameter such that
the
expanded inner diameter of the liner 430 corresponds to the inner diameter of
the
casing 420. A more detailed description of the setting tool and expansion tool
can be
found in U.S. Patent Application Publication No. 2003/0127225. The compressive
state
of the liner 430 enhances the expansion process and requires less force from
the rotary
expander tool 480 than conventional methods. Once the desired expansion of the
liner
is complete, the liner 430 can be cemented in place, and the annulus between
the liner
430 and the casing 420 proximate the anchor 470 can be sealed.
Figure 11 shows creation of a bulge formed monobore shoe, which can be an
additional step to the method described in Figures 8-10. Once the liner 430 is
on the
bottom of the wellbore 400, weight is applied to the liner 430 to place the
liner 430 in
compression. The bottom of the liner 430 is then expanded by fluid pressure
applied to
the inner surface of the liner 430 to form a bell shaped end 500. For some
embodiments, the material used at the bell shaped end 500 of the liner 430 has
a
thinner wall thickness than the rest of the liner 430 and/or is shaped pipe in
order to
facilitate expansion thereof and provide the bell shaped end 500 upon
expansion.
Further, the bell shaped end 500 may be hydraulically isolated from the rest
of the liner
such that the fluid pressure is applied to only the bell shaped end 500.
Additional bell
shaped ends (not shown) having smaller diameters than the bell shaped end 500
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CA 02551067 2006-06-27
be located above the bell shaped end 500. These additional bell shaped ends
may be
formed by application of a different fluid pressure than applied to the bell
shaped end
500 and/or they may be formed of a different material than the bell shaped end
500.
The remainder of the liner 430 can be expanded using any expansion method such
as
a rotary expansion, a swedge or cone, hydraulic pressure and any methods
described
above.
Any of the expandable tubing described above can be longitudinally corrugated
tubing or shaped pipe in order to further facilitate expansion. Using shaped
pipe or
corrugated tubing also reduces the tendency for pipe to buckle. This allows
for
compression of longer lengths of pipe enhancing the expansion process further.
Further, the methods described above can be used in any type of down hole
tubular expansion including but not limited to liner hangers, packers,
straddles, PBRs,
drilling-with-liner, etc.
While the foregoing is directed to embodiments of the present invention, other
and further embodiments of the invention may be devised without departing from
the
basic scope thereof, and the scope thereof is determined by the claims that
follow.
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