Note: Descriptions are shown in the official language in which they were submitted.
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TUBULAR EXPANSION METHOD
FIELD OF THE INVENTION
[0001] The field of this invention is tools that expand tubulars and more
particularly tools that employ pressure retained by cup shaped seals to
accomplish the
expansion.
BACKGROUND OF THE INVENTION
[0002] In the late 1990s the technique of expansion of tubulars started to
become
widely used downhole. There were several applications such as casing patches,
screen
expansions in lieu of gravel packing, and expansion of casing or slotted
liners as part of
well completion. Different mechanical swages were devised that could be pushed
or
pulled through tubulars. These swages were of the fixed dimension variety or
incorporated rollers that had the ability to extend or retract. Another
technique that was
developed utilized inflatable bladders to perform the expansion.
[0003] While these techniques were effective, they had drawbacks. Mechanical
swages could get stuck before the expansion was complete and were problematic
to use if
there was any significant deviation in the welibore. Rigid tubing was
necessary in order
to be able to transmit significant pulling forces from the surface to the
swage. The
inflatables proved costly to run and, due to their complexity, occasionally
failed to inflate
or burst due to well conditions during run in or when in position for
inflation. The nature
of inflatables limited the available expansion force due to the pressure
rating of the
inflatable. What was needed was a simpler technique that could expand a
tubular
downhole that did not have the limitations of the known techniques described
above.
[0004] Cup type seals have been in oilfield use for a long time. They have,
among
other things, been used to pressure test tubulars for pinhole leaks or
fractures. One such
CA 02645401 2008-11-21
device is illustrated in U.S. Patent 4,149,566 in its figure 5. It describes
the test rig involving a
mandrel with opposed test cups to isolate the zone to be pressure tested with
fluid to be delivered
between the cups. This reference describes the limited reliability of
predecessor test cups to
withstand the rigors of testing thousands of feet of tubulars and the need for
frequent cup
replacements.
[0005] Yet, despite the use of test cups for pressure testing tubing being
known since the
1970s and the rapid commercialization of the expansion of tubulars downhole in
the late 1990s,
there has heretofore been no known device that incorporates the use of cup
type seal elements in a
device to expand tubulars. The present invention allows, among other
applications, the insertion of
cladding into existing casing and expanding it into a sealed engagement with
existing casing. In the
context of this application "cladding" comprises, among other things, a sleeve
or a scroll that stays
expanded due to a ratchet or other device, casing or tubing. It can also be
used to expand casing or
tubing. Depending on the mounting of the cup seals, the tool can be
repositioned to sequentially
expand long lengths of cladding, casing or tubing. These and other advantages
will be more
apparent to those skilled in the art from a review of the description of the
preferred embodiment
and the claims below.
[0006] Also related to cladding expansion are U.S. Patents 2,812,025 (showing
expansion
of a scroll downhole), 4,099,563 and 5,803,177 (showing packer cups used in a
downhole tool).
SUMMARY OF THE INVENTION
[0007] In one variation, a tool is disclosed that can run a section of
cladding into casing
where the cladding interior is closed off by opposed cup seals and access to
the volume between
the cup seals exists through the tool body. Pressure is applied to the
interior of the cladding to
expand it into anchored and sealed contact with the casing. An exterior
gripping surface can be
provided on the cladding to enhance grip upon expansion. The tool can be
repositioned to
expand lengths of cladding.
[0007a] Accordingly, in one aspect of the present invention there is provided
a method of
expanding a tubular downhole, comprising:
providing an expansion tool comprising a pair of seals spaced from each other
on a
body;
positioning said tubular and said expansion tool in the wellbore;
pressurizing the tubular between said seals;
expanding the tubular;
providing a flow path through said body; and
selectively blocking said flow path to allow said pressurizing.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Figure 1 is a section view of the apparatus running in a cladding into
casing;
[0009] Figure 2 is the view of Figure 1 in the cladding -expanded position;
[0010] Figure 3 is a detailed view of the teeth pattern on the exterior of the
cladding to promote grip upon expansion.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0011] Referring to Figure 1 a work string 10 is connected to top sub 12 at
thread
14. Top sub 12 is connected to body 16 at thread 18. Bottom sub 20 is
connected at
thread 22to body 16. Passage 24 extends through top sub 12, body 16 and bottom
sub 20.
A ball seat 26 is connected to bottom sub 20 and shear pins 28 secure its
position. A ball
30 can be dropped on seat 26 to allow passage 24 to be pressurized. Passage 24
has
lateral outlets 32 that lead to annular space 34 outside body 16 and between
cup seals 36
and 38, which are respectively backed by thimbles 40 and 42. Cladding 44 has
been
pushed over cup seals 36 and 38 to close off annular space 34. A running tool
(not
shown) is attached to work string 10 so that cladding 44 can be supported from
the work
string 10. The cladding 44 has an exterior tooth profile 46 made. up of a
plurality of teeth
48, shown in detail in Figure 3. Teeth 48, upon expansion of cladding 44, dig
into casing
50.
[0012] In operation, a ball 30 is dropped on seat 26 and pressure upwards of
10,000 pounds per square inch (PSI) is applied. The pressure is communicated
between
cup seals 36 and 38 to expand cladding 44 into sealing contact with casing 50.
Teeth 48 dig into casing 50 to secure cladding 44. Cup seals 36 and 38 can be
in pairs near the upper and lower ends of the cladding 44 so that the
expansion, as well as sealing and anchoring, will be at opposed ends of
the cladding. Alternatively, the cup seals 36 and 38 can be at one end,
preferably the lower end, of cladding 44 so that upon expansion,. one end is
sealed and
anchored. Thereafter, a sewage S, shown schematically in Figure 2 as located
above
cup seals 36 and 38 but which can also be placed between them, can be
energized
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to run from the expanded zone of the cladding 44 by pulling the work string,
wliich
supports the swage uphole and out of the cladding 44 to expand the balance of
the
cladding. Sleeve 52 is used to keep cups 36 and 38 separate and at opposite
ends of
annular space 34 during tool assembly. When the expansion of cladding 44 is
complete,
the ball seat is released by further pressure application to break shear pins
28. The work
string 10 can be pulled without pulling a wet string, as the passage 24 is
again open at the
bottom. It should be noted that the bottom sub could have a check valve
instead of ball
seat 26. The check a valve allows fluid into passage 24 for run in but
prevents fluid from
passing in the opposite direction. When it is time to pull the work string 10,
the entire
check valve assembly can be blown out by raising pressure in passage 24 and
breaking
shear pins that hold the check valve. Yet other ways to temporarily block the
passage 24
to allow expansion with pressure applied between cup seals 36 and 38 are
within the
scope of the invention. The cup seals 36 and 38 are commercial products
available from
Global Elastonneric Products located in Bakersfield, CA, under the product
designation 5
%z" 15/17# Packer Cup w/ O-Ring Groove 80/90 HD (E105502H6291189). The
expansion of the cladding 44 allows the work string to be removed from the
well as the
sleeve remains in sealed contact with the casing 50. The apparatus described
can also
expand cladding into tubing as well as casing 50. It should also be noted that
the
expansion could be accomplished on a volumetric basis of fluid pumped between
the cup
seals 36 and 38. A positive displacement pump can be used or/and some type of
flow
measurement to insure that the proper amount of expansion is achieved without
over-
expansion. The annular space could be vented to allow it to fill with a known
volume of
fluid short of expansion of the cladding 44, at which point the vent can close
and a
predetermined volume pumped in to get the desired expansion. In a variation,
the annular
space 34 can be initially evacuated to dispense with the need for a vent.
j00131 In an alternative embodiment the apparatus A can be reconfigured so
that
it cari be repositioned for repeated uses, such as expansion of long lengths
of casing,
tubing, liners or cladding. To do this the backing rings 40 and 42 can be
reconfigured to
extend outwardly a little more and are mounted to be selectively responsive to
an applied
force, represented schematically by arrows 58 and 60. When this happens in the
absence
of pressure in annular space 34 the cup seals 36 and 38 can flex sufficiently
to move the
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apparatus A without damage to the cup seals 36 and 38. After movement of the
apparatus
A the backing rings 40 and 42 can be retracted and the cycle is repeated.
[0014] Those skilled in the art will appreciate that this technique is far
more
economical than using an inflatable or a swage. A pressure booster (not shown)
can be
located above the apparatus A so that surface pressures in the order of about
3,000 PSI
can be boosted at the apparatus A to over 10,00 PSI. The cup seals are usable
to high
temperatures in excess of 200 degrees Fahrenheit. The cup seals can be stored
on site and
quickly renewed, if necessary, during a lengthy expansion or if otherwise
damaged when
cladding 44 is passed over them.
[0015] While the preferred embodiment has been described above, those skilled
in the art will appreciate that other mechanisms are contemplated to
accomplish the task
of this invention, whose scope is delimited by the claims appended below,
properly
interpreted for their literal and equivalent scope.
