Note: Descriptions are shown in the official language in which they were submitted.
CA 02683103 2009-10-27
METHOD AND APPARATUS FOR EXPANDING AND SEPARATING
TUBULARS IN A WELLBORE
This is a divisional application of Canadian Patent Application Serial No.
2,462,115 filed
on September 26, 2002.
The present invention relates to methods and apparatus for wellbore
completions. More
particularly, the invention relates to completing a wellbore by expanding
tubulars therein.
More particularly still, the invention relates to completing a wellbore by
separating an
upper portion of a tubular from a lower portion after the lower portion of the
tubular has
been expanded into frictional engagement with another tubular therearound, or
into
contact with a surrounding wellbore formation.
It should be understood that the expression "the invention" and the like
encompasses the
subject-matter of both the parent and the divisional applications.
Hydrocarbon and other wells are completed by forming a borehole in the earth
and then
lining the borehole with steel 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.
It is common to employ more than one string of casing in a wellbore. In this
respect, a first
string of casing is set in the welibore when the well is drilled to a first
designated depth. In
this respect, the first string of casing is hung from the surface, and then
cement is circulated
into the annulus behind the casing. The well is then drilled to a second
designated depth, and
a second string of casing, or liner, is run into the well. The second string
is set at a depth
such that the upper portion of the second string of casing overlaps the lower
portion of the
first string of casing. The second liner string is then fixed or "hung off of
the existing casing
CA 02683103 2009-10-27
la
by the use of slips which utilize slip members and cones to wedgingly fix the
new string of
liner in the welibore. The second casing string is then cemented. This process
is typically
repeated with additional casing strings until the well has been drilled to
total depth. In this
manner, wells are typically formed with two or more strings of casing of an
ever decreasing
diameter.
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2
Apparatus and methods are emerging that permit tubulars to be expanded in
situ. The
apparatus typically includes expander tools which are fluid powered and are
run into a
wellbore on a working string. The hydraulic expander tools include radially
expandable
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 expansion 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 weilbore and/or moving the expander tool axially in the wellbore
with the
expansion member actuated, a tubular can be expanded along a predetermined
length in a
wellbore.
There are advantages to expanding a tubular within a wellbore. For example,
expanding a
second tubular into contact with a first tubular therearound eliminates the
need for a
conventional slip assembly. With the elimination of the slip assembly, the
annular space
required to house the slip assembly between the two tubulars can be reduced.
In one example of utilizing an expansion tool and expansion technology, a
liner can be hung
off of an existing string of casing without the use of a conventional slip
assembly. A new
section of liner is run into the wellbore using a run-in string. As the
assembly reaches that
depth in the wellbore where the liner is to be hung, the new liner is cemented
in place.
Before the cement sets, an expander tool is actuated and the liner is expanded
into contact
with the existing casing therearound. By rotating the expander tool in place,
the new lower
string of casing can be fixed onto the previous upper string of casing, and
the annular area
between the two tubulars is sealed.
There are problems associated with the installation of a second string of
casing in a wellbore
using an expander tool. Because the weight of the casing must be borne by the
run-in string
during cementing and expansion, there is necessarily a portion of surplus
casing remaining
above the expanded portion. In order to properly complete the well, that
section of surplus
unexpanded casing must be removed in order to provide a clear path through the
wellbore in
the area of transition between the first and second casing strings.
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Known methods for severing a string of casing in a wellbore present various
drawbacks. For
example, a severing tool may be run into the wellbore that includes cutters
which extend into
contact with the tubular to be severed. The cutters typically pivot away from
a body of the
cutter. Thereafter, through rotation the cutters eventually sever the tubular.
This approach
requires a separate trip into the wellbore, and the severing tool can become
binded and may
otherwise malfunction. The severing tool can also interfere with the upper
string of casing.
Another approach to severing a tubular in a welibore includes either
explosives or chernicals.
These approaches likewise require a separate trip into the wellbore, and
involve the expense
and inconvenience of transporting and using additional chemicals during well
completion.
These methods also create a risk of interfering with the upper string of
casing. Another
possible approach is to use a separate fluid powered tool, like an expansion
tool wherein one
of the expansion members is equipped with some type of rotary cutter. This
approach,
however, requires yet another specialized tool and manipulation of the run-in
string in the
wellbore in order to place the cutting tool adjacent that part of the tubular
to be severed. The
approach presents the technical problem of operating two expansion tools
selectively with a
single tubular string.
There is a need, therefore, for an improved apparatus and method for severing
an upper
portion of a string of casing after the casing has been set in a wellbore by
expansion means.
There is a further need for an improved method and apparatus for severing a
tubular in a
wellbore. There is yet a further need for a method and apparatus to quickly
and simply sever
a tubular in a wellbore without a separate trip into the weilbore and without
endangering the
integrity of the upper string of casing.
Apparatus aspects corresponding to method aspects disclosed herein are also
provided, and
vice versa.
According to an embodiment, there is provided a method comprising:
positioning a first tubular within a wellbore;
placing a scribe within the top portion of a second tubular;
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running the second tubular to a selected depth within the we.llbore such that
the top
portion of the second tubular overlaps with a bottom portion of the first
tubular;
expanding the top portion of the second tubular at the depth of said scribe so
that the
outer surface of the expanded top portion of the second tubular is in
frictional contact with
the inner surface of the bottom portion of the first tubular, and thereby
severing the top
portion of the second tubular into an upper and lower portion; and
removing said severed upper portion of said top portion of the second tubular
from
the wellbore.
According to an embodiment, an expansion assembly is run into a wellbore on a
run-in
string. The expansion assembly comprises a lower string of casing to be hung
in the
welibore, and an expander tool disposed at an upper end thereof. The expander
tool
preferably includes a plurality of expansion members which are radially
disposed around a
body of the tool in a spiraling arrangement. In addition, the lower string of
casing includes a
scribe placed in the lower string of casing at the point of desired severance.
The scribe
creates a point of structural weakness within the wall of the casing so that
it fails upon
expansion.
The expander tool is run into the wellbore to a predetermined depth where the
lower string of
casing is to be hung. In this respect, a top portion of the lower string of
casing, including the
scribe, is positioned to overlap a bottom portion of an upper string of casing
already set in
the wellbore. In this manner, the scribe in the lower string af casing is
positioned downhole
at the depth where the two strings of casing overlap. Cement is injected
through the run-in
string and circulated into the annular area between the lower string of casing
and the
formation. Cement is further circulated into the annulus where the lower and
upper strings
of casing overlap. Before the cement cures, the expansion members at a lower
portion of the
expansion tool are actuated so as to expand the lower string of casing into
the existing upper
string at a point below the scribe. As the uppermost expansion members extend
radially
outward into contact with the casing, including those at the depth of the
scribe, the scribe
causes the casing to be severed. Thereafter, with the lower string of casing
expanded into
frictional and sealing relationship with the existing upper casing string, the
expansiori tool
and run-in string, are pulled from the wellbore.
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4a
According to an aspect of the present invention there is provided a method for
expanding
and separating a tubular in a wellbore, the method comprising:
positioning a first tubular within a wellbore;
providing a second tubular having a preferred line of fracture within a top
portion
thereof;
running the second tubular to a selected depth within the wellbore such that
the top
portion of the second tubular overlaps with a portion of the first tubular;
expanding at least a portion of the top portion of the second tubular at
and/or below the
preferred line of fracture so that the outer surface of the expanded portion
of the second
tubular is in frictional contact with the inner surface of said portion of the
first tubular,
and thereby severing the top portion of the second tubular into an upper and
lower
portion; and
removing said severed upper portion of said top portion of the second tubular
from the
wellbore.
According to another aspect of the present invention there is provided a
method of
expanding a second tubular into a first tubular within a wellbore, comprising:
lowering the second tubular to a selected depth within the wellbore so that a
portion of
the second tubular overlaps with a portion of the first tubular, a portion of
a surface of the
second tubular having a scribe therein;
expanding the portion of the second tubular so that an outer surface of the
second
tubular is in frictional contact with an inner surface of the first tubular at
the overlap,
thereby severing the second tubular into an upper and lower portion at the
scribe; and
removing the severed upper portion of the second tubular from the wellbore.
According to a further aspect of the invention there is provided an apparatus
for
expanding and separating a tubular in a weilbore, the tubular having an
inscribed portion,
the apparatus comprising:
an expander tool disposed within the inscribed tubular and connected thereto,
the
expander tool having first extendable roller members for causing the tubular
to fail at the
inscribed portion and second extendable roller members,
CA 02683103 2009-10-27
4b
wherein the tubular is disposed within a wellbore and expandable into
frictional contact
with the wellbore by the second extendable roller members, the second
extendable roller
members extendable prior to the first extendable roller members.
According to a further aspect of the present invention there is provided a
tubular for
insertion into a welibore, the tubular having a preferred line of fracture
within a top
portion thereof so as to permit severing of the top portion into an upper and
a lower
portion by expansion of at least a portion of the top portion at and/or below
the preferred
line of fracture.
According to a further aspect of the invention there is provided a system for
completing a
wellbore comprising the tubular as described hereinabove and an expander tool.
According to a further aspect of the invention there is provided a method for
expanding a
second tubular into a first tubular, the first tubular and second tubular each
having a top
portion and a bottom portion, comprising the steps of:
positioning the first tubular within a wellbore;
placing a scribe within the top portion of the second tubular;
running the second tubular to a selected depth within the wellbore such that
the top
portion of the second tubular overlaps with the bottom portion of the first
tubular;
expanding the top portion of the second tubular at the depth of said scribe so
that the
outer surface of the expanded top portion of the second tubular is in
frictional contact
with the inner surface of the bottom portion of the first tubular, and thereby
severing the
top portion of the second tubular into an upper and lower portion; and
removing said severed upper portion of said top portion of the second tubular
from the
wellbore.
According to a further aspect of the present invention there is provided an
apparatus for
expanding and separating a tubular in a wellbore, the tubular having an
inscribed portion,
the apparatus comprising:
an expander tool disposed within the inscribed tubular and connected thereto,
the
expander tool having at least one first extendable roller member for causing
the tubular to
fail at the inscribed portion and at least one second extendable roller
member,
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4c
wherein the tubular is disposed within a welibore and expandable into
frictional contact
with the wellbore by the at least one second extendable roller member, the at
least one
second extendable roller member extendable prior to the at least one first
extendable
roller member.
According to an aspect of the present invention there is provided an expander
tool for
expanding a tubular, the tool comprising:
a body having a bore longitudinally formed therein;
at least one first roller member radially extendable from the body into
contact with a
surrounding inside surface of the tubular; and
at least one second roller member constructed and arranged to extend from the
body
after the at least one first roller member has been extended therefrom.
According to another aspect of the present invention there is provided an
expander tool
for expanding a tubular, comprising:
a body having a longitudinal bore therein; and
at least two expansion members radially extendable from the body into contact
with a
surrounding inside surface of the tubular, wherein the at least two expansion
members are
radially extendable at different times.
According to a further aspect of the present invention there is provided a
method of
expanding a tubular, comprising:
providing an expander tool within a tubular, the expander tool comprising at
least two
expansion members radially extendable from a body having a longitudinal bore
therethrough;
radially extending one of the at least two expansion members into contact with
an inside
surface of the tubular; and
thereafter radially extending another of the at least two expansion members
into contact
with the inside surface of the tubular.
According to a further aspect of the present invention there is provided a
method of
expanding a tubular, comprising:
running an expansion assembly that is supporting a tubular into a wellbore;
.I. . . . . .. .
CA 02683103 2009-10-27
4d
actuating the expansion assembly to expand a first portion of the tubular
while
preventing expansion of a second portion of the tubular; and
actuating the expansion assembly to expand the second portion of the tubular,
thereby severing the second portion of the tubular from the first portion of
the tubular.
According to a further aspect of the present invention there is provided a
method of
expanding a tubular, comprising:
running a tubular that is supported by an expansion assembly having a first
member and
a second member into a wellbore;
actuating the first member to expand a first portion of the tubular while
preventing
actuation of the second member; and
actuating the second member to expand a second portion of the tubular.
According to a further aspect of the present invention there is provided an
apparatus for
expanding a tubular, comprising:
a body having a bore disposed through the body;
a first member that is radially extendable from the body; and
a second member that is radially extendable from the body and is configured to
extend
from the body after extension of the first member.
) . . . . . ... . . .. .. . .
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Some preferred embodiments of the invention will now be described by way of
example only
and with reference to the accompanying drawings, in which:
Figure 1 is a partial section view of a wellbore illustrating the assembly
according to an
embodiment of the present invention in a run-in position.
Figure 2 is an enlarged sectional view of a wall in the lower string of casing
more fully
showing one embodiment of a scribe of the present invention.
Figure 3 is an exploded view of an expander tool as might be used in the
methods of the
present invention.
Figure 4 is a perspective view showing a shearable connection for an expansion
member.
Figures 5A - 5D are section views taken along a line 5-5 of Figure 1 and
illustrating the
position of expansion members during progressive operation of the expansion
tool.
Figure 6 is a partial section view of the apparatus in a wellbore illustrating
a portion of the
lower string of casing, including slip and sealing members, having been
expanded into the
upper string of casing therearound.
Figure 7 is a partial section view of the apparatus illustrating the lower
string of casing
expanded into frictional and sealing engagement with the upper string of
casing. Figure 7
further depicts the lower string of casing having been severed into an upper
portion and a
lower portion due to expansion.
Figure 8 is a partial section view of the wellbore illustrating a section of
the lower casing
string expanded into the upper casing string after the expansion tool and run-
in string have
been removed.
Figure 9 is a cross-sectional view of an expander tool residing within a
wellbore. Above the
expander tool is a torque anchor for preventing rotational movement of the
lower string of
casing during initial expansion thereof. Expansion of the casing has not yet
begun.
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6
Figure 10 is a cross-sectional view of an expander tool of FIG. 9. In this
view, the torque
anchor and expander tool have been actuated, and expansion of the lower casing
string has
begun.
Figure 1 is a section view of a wellbore 100 illustrating an apparatus 105 for
use in the
methods of the present invention. The apparatus 105 defines a string of casing
130, and an expander tool 120 for expanding the string of casing 130. By
actuation of the
expander tool 120 against the inner surface of the string of casing 130, the
string of casing
130 is expanded into a second, upper string of casing 110 which has already
been set in the
wellbore 100. In this manner, the top portion of the lower string of casing
130U is placed in
frictional engagement with the bottom portion of the upper string of casing
110.
In accordance with the present invention, a scribe 200 is placed into the
surface of the lower
string of casing 130. An enlarged view of the scribe 200 in one embodiment is
shown in
Figure 2. As will be disclosed in greater detail, the scribe 200 creates an
area of structural
weakness within the. lower casing string 130. When the lower string of casing
130 is
expanded at the depth of the scribe 200, the lower string of casing 130 is
severed into upper
130U and lower 130L portions. The upper portion 130U of the lower casing
string 130 can
then be easily removed from the wellbore 100. Thus, the scribe may serve as a
release
mechanism for the lower casing string 130.
At the stage of completion shown in Figure 1, the wellbore 100 has been lined
with the
upper string of casing 110. A working string 115 is also shown in FIG. 1.
Attached to a
lower end of the run-in string 115 is an expander tool 120. Also attached to
the working
string 115 is the lower string of casing 130. In the embodiment of FIG. 1, the
lower string of
casing 130 is supported during run-in by a series of dogs 135 disposed
radially about the
expander tool 120. The dogs 135 are landed in a circumferential profile 134
within the upper
string of casing 130.
A sealing ring 190 is disposed on the outer surface of the lower string of
casing 130. In the
preferred embodiment, the sealing ring 190 is an elastomeric member
circumferentially fitted
onto the outer surface of the casing 130. However, non-elastomeric materials
may also be
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7
used. The sealing ring 190 is designed to seal an annular area 201 formed
between the outer
surface of the lower string of casing 130 and the inner surface of the upper
string of casing
110 upon expansion of the lower string 130 into the upper string 110.
Also positioned on the outer surface of the lower string of casing 130 is at
least one slip
member 195. In the preferred embodiment of the apparatus 105, the slip member
195
defines a pair of rings having grip surfaces formed thereon for engaging the
inner surface of
the upper string of casing 110 when the lower string of casing 130 is
expanded. In the
embodiment shown in FIG. 1, one slip ring 195 is disposed above the sealing
ring 190, and
one slip ring 195 is disposed below the sealing ring 190. In Figure 1, the
grip surface
includes teeth formed on each slip ring 195. However, the slips could be of
any shape and
the grip surfaces could include any number of geometric shapes, including
button-like inserts
(not shown) made of high carbon material.
Fluid is circulated from the surface and into the wellbore 100 through the
working string
115. A bore 168, shown in Figure 3, runs through the expander tool 120,
placing the
working string 115 and the expander tool 120 in fluid communication. A fluid
outlet 125 is
provided at the lower end of the expander tool 120. In the preferred
embodiment, shown in
FIG. 1, a tubular member serves as the fluid outlet 125. The fluid outlet 125
serves as a
fluid conduit for cement to be circulated into the wellbore 100 in accordance
with the method
of the present invention.
In the embodiment shown in Figure 1, the expander tool 120 includes a swivel
138. The
swivel 138 allows the expander tool 120 to be rotated by the working tubular
115 while the
supporting dogs 135 remain stationary.
Figure 3 is an exploded view of the expander tool 120 itself. The expander
tool 120 consists
of a cylindrical body 150 having a plurality of windows 155 formed
therearound. Within
each window 155 is an expansion assembly 160 which includes a roller 165
disposed on an
axle 170 which is supported at each end by a piston 175. The piston 175 is
retained in the
body 150 by a pair of retention members 172 that are held in place by screws
174. The
assembly 160 includes a piston surface 180 formed opposite the piston 175
which is acted
upon by pressurized fluid in the bore 168 of the expander tool 120. The
pressurized fluid
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8
causes the expansion assembly 160 to extend radially outward and into contact
with the inner
surface of the lower string of casing 130. With a predetermined amount of
fluid pressure
acting on the piston surface 180 of piston 175, the lower string of casing 130
is expanded
past its elastic limits.
The expander tool 120 illustrated in FIGS. 1 and 3 includes expansion
assemblies 160 that
are disposed around the perimeter of the expander tool body 150 in a spiraling
fashion.
Located at an upper position on the expander tool 120 are two opposed
expansion assemblies
160 located 180 apart. The expander tool 120 is constructed and arranged
whereby the
uppermost expansion members 161 are actuated after the other assemblies 160.
In one embodiment, the uppermost expansion members 161 are retained in their
retracted
position by at least one shear pin 162 which fails with the application of a
predetermined
radial force. In Figure 4 the shearable connection is illustrated as two pin
members 162
extending from a retention member 172 to a piston 175. When a predetermined
force is
applied between the pistons 175 of the uppermost expansion members 161 and the
retaining
pins 162, the pins 162 fail and the piston 175 moves radially outward. In this
manner,
actuation of the uppermost members 161 can be delayed until all of the lower
expansion
assemblies 160 have already been actuated.
Figures 5A - 5D are section views of the expander tool 120 taken along lines 5-
5 of Figure
1. The purpose of Figures 5A - 5D is to illustrate the relative position of
the various
expansion assemblies 160 and 161 during operation of the expander tool 120 in
a wellbore
100. Figure 5A illustrates the expander tool 120 in the run-in position with
all of the
radially outward extending expansion assemblies 160, 161 in a retracted
position within the
body 150 of the expander tool 120. In this position, the expander tool 120 can
be run into a
wellbore 100 without creating a profile any larger than the outside diameter
of the expansion
tool body 150. Figure 5B illustrates the expander tool 120 with all but the
upper-most
expansion assemblies 160 and 161 actuated. Because the expansion assemblies
160 are
spirally disposed around the body 150 at different depths, in Figure 5B the
expander tool
120 would have expanded a portion of the lower string of casing 130 axially as
well as
radially. In addition to the expansion of the lower string of casing 130 due
to the location of
the expansion assemblies 160, the expander tool 120 and working string 115 can
be rotated
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9
relative to the lower string of casing 130 to form a circumferential area of
expanded liner
130L. Rotation is possible due to a swivel 138 located above the expander tool
120 which
permits rotation of the expander tool 120 while ensuring the weight of the
casing 130 is
bome by the dogs 135.
Figure 6 presents a partial section view of the apparatus 105 after expanding
a portion of the
lower string of casing 130L into the upper string of casing 110. Expansion
assemblies 160
have been actuated in order to act against the inner surface of the lower
string of casing
130L. Thus, Figure 6 corresponds to Figure 5B. Visible also in Figure 6 is
sealing ring
190 in contact with the inside wall of the casing 110. Slips 195 are also in
contact with the
upper string of casing 110.
Figure 5C is a top section view of a top expansion member 160 in its recessed
state. Present
in this view is a piston 175 residing within the body 150 of the expander tool
120. Also
present is the shearable connection, i.e., shear pins 162 of FIG. 4.
Referring to Figure 5D, this figure illustrates the expander tool 120 with all
of the expansion
assemblies 160 and 161 actuated, including the uppermost expansion members
161. As
previously stated, the uppermost expansion members 161 are constructed and
arranged to
become actuated only after the lower assemblies 160 have been actuated.
Figure 7 depicts a wellbore 100 having an expander tool 120 and lower string
of casing 130
according to an embodiment of the present invention disposed therein. In this
view, all of
the expansion assemblies 160, 161, including the uppermost expansion members
161, have
been actuated. Thus, Figure 7 corresponds to the step presented in Figure 5D.
Referring again to Figure 1, formed on the surface of the lower string of
casing 130L
adjacent the uppermost expansion member 161 is a scribe 200. The scribe 200
creates an
area of structural weakness within the lower casing string 130. When the lower
string of
casing 130 is expanded at the depth of the scribe 200, the lower string of
casing 130 breaks
cleanly into upper 130U and lower 130L portions. The upper portion 130U of the
lower
casing string 130 can then be easily removed from the wellbore 100.
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The inventors have determined that a scribe 200 in the wall of a string of
casing 130 or other
tubular will allow the casing 130 to break cleanly when radial outward
pressure is placed at
the point of the scribe 200. The depth of the cut 200 needed to cause the
break is dependent
upon a variety of factors, including the tensile strength of the tubular, the
overall deflection
of the material as it is expanded, the profile of the cut, and the weight of
the tubular being
hung. Thus, the scope of the present invention is not limited by the depth of
the particular
cut or cuts 200 being applied, so long as the scribe 200 is shallow enough
that the tensile
strength of the tubular 130 supports the weight below the scribe 200 during
run-in. The
preferred embodiment, shown in Figure 2, employs a single scribe 200 having a
V-shaped
profile so as to impart a high stress concentration onto the casing wall.
In the preferred embodiment, the scribe 200 is formed on the outer surface of
the lower string
of casing 130. Further, the scribe 200 is preferably placed around the casing
130
circumferentially. Because the lower string of casing 130 and the expander
tool 120 are run
into the wellbore 100 together, and because no axial movement of the expander
tool 120 in
relation to the casing 130 is necessary, the position of the upper expansion
members 161
with respect to the scribe 200 can be predetermined and set at the surface of
the well or
during assembly of the apparatus 105.
Figure 7, again, shows the expander tool 120 with all of the expansion
assemblies 160 and
161 actuated, including the uppermost expansion members 161. In Figure 7, the
scribe 200
has caused a clean horizontal break around a perimeter of the lower string of
casing 130 such
that a lower portion of the casing 130L has separated from an upper portion
130U thereof.
In addition to the expansion assemblies 160 and 161 having been actuated
radially outward,
the swivel 138 permitted the run-in string 115 and expansion tool 120 to be
rotated within
the wellbore 100 independent of the casing 130, ensuring that the casing 130
is expanded in a
circumferential manner. This, in turn, results in an effective hanging and
sealing of the lower
string of casing 130 upon the upper string of casing 110 within the wellbore
100. Thus, the
apparatus 105 enables a lower string of casing 130 to be hung onto an upper
string of casing
110 by expanding the lower string 130 into the upper string 110.
Figure 8 illustrates the lower string of casing 130 set in the wellbore 100
with the run-in
string 115 and expander tool 120 removed. In this view, expansion of the lower
string of
. . . , ~ . . . . . . . . . . ... . . . . . . .
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11
casing 130 has occurred. The slip rings 195 and the seal ring 190 are engaged
to the inner
surface of the upper string of casing 110. Further, the annulus 201 between
the lower string
of casing 130 and the upper string of casing has been filled with cement,
excepting that
portion of the annulus which has been removed by expansion of the lower string
of casing
130.
In operation, the method and apparatus of the present invention can be
utilized as follows: a
wellbore 100 having a cemented casing 110 therein is drilled to a new depth.
Thereafter, the
drill string and drill bit are removed and the apparatus 105 is run into the
wellbore 100 . The
apparatus 105 includes a new string of inscribed casing 130 supported by an
expander tool
120 and a run-in string 115. As the apparatus 105 reaches a predetermined
depth in the
wellbore 100, the casing 130 can be cemented in place by injecting cement
through the run-
in string 115, the expander tool 120 and the tubular member 125. Cement is
then circulated
into the annulus 201 between the two strings of casing 110 and 130.
With the cement injected into the annulus 201 between the two strings of
casing 110 and
130, but prior to curing of the cement, the expander tool 120 is actuated with
fluid pressure
delivered from the run-in string 115. Preferably, the expansion assemblies 160
(other than
the upper-most expansion members 161) of the expander tool 120 extend radially
outward
into contact with the lower string of casing 130 to plastically deform the
lower string of
casing 130 into frictional contact with the upper string of casing 110
therearound. The
expander tool 120 is then rotated in the wellbore 100 independent of the
casing 130. In this
manner, a portion of the lower string of casing 130L below the scribe 200 is
expanded
circumferentially into contact with the upper string of casing 110.
After all of the expansion assemblies 160 other than the uppermost expansion
members 161
have been actuated, the uppermost expansion members 161 are actuated.
Additional fluid
pressure from the surface applied into the bore 168 of the expander tool 120
will cause a
temporary connection 162 holding the upper expansion members 161 within the
body 150 of
the expander tool 120 to fail. This, in turn, will cause the pistons 175 of
the upper expansion
members 161 to move from a first recessed position within the body 150 of the
expander tool
120 to a second extended position. Rollers 165 of the uppermost expansion
members 161
then act against the inner surface of the lower string of casing 130L at the
depth of the scribe
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200, causing an additional portion of the lower string of casing 130 to be
expanded against
the upper string of casing 110.
As the uppermost expansion members 161 contact the lower string of casing 130,
a scribe
200 formed on the outer surface of the lower string of casing 130 causes the
casing 130 to
break into upper 130U and lower 130L portions. Because the lower portion of
the casing
130L has been completely expanded into contact with the upper string of casing
110, the
lower portion of the lower string of casing 130L is successfully hung in the
wellbore 100.
The apparatus 105, including the expander tool 120, the working string 115 and
the upper
portion of the top end of the lower string of casing 130U can then be removed,
leaving a
sealed overlap between the lower string of casing 130 and the upper string of
casing 110, as
illustrated in Figure S.
Figures 5A-5D depict a series of expansions in sequential stages. The above
discussion
outlines one embodiment of the method of the present invention for expanding
and
separating tubulars in a wellbore through sequential stages. However, it is
within the scope
of the present invention to conduct the expansion in a single stage. In this
respect, the
method of the present invention encompasses the expansion of rollers 165 at
all rows at the
same time. Further, the present invention encompasses the use of a rotary
expander tool 120
of any configuration, including one in which only one row of roller assemblies
160 is
utilized. With this arrangement, the rollers 165 would need to be positioned
at the depth of
the scribe 200 for expansion. Alternatively, the additional step of raising
the exparider tool
120 across the depth of the scribe 200 would be taken. Vertically translating
the expander
tool 120 could be accomplished by raising the working string 115 or by
utilizing an actuation
apparatus downhole (not shown) which would translate the expander tool 120
without raising
the drill string 115.
It is also within the scope of the present invention to utilize a swaged cone
(not shown) in
order to expand a tubular in accordance with the present invention. A swaged
conical
expander tool expands by being pushed or otherwise translated through a
section of tubular
to be expanded. Thus, the present invention is not limited by the type of
expander tool
employed.
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As a further aid in the expansion of the lower casing string 130, a torque
anchor may
optionally be utilized. The torque anchor serves to prevent rotation of the
lower string of
casing 130 during the expansion process. Those of ordinary skill in the art
may perceive that
the radially outward force applied by the rollers 165, when combined with
rotation of the
expander tool 120, could cause some rotation of the casing 130.
In one embodiment, the torque anchor 140 defines a set of slip members 141
disposed
radially around the lower string of casing 130. In the embodiment of Figure 1,
the slip
members 141 define at least two radially extendable pads with surfaces having
gripping
formations like teeth formed thereon to prevent rotational movement. In FIG.
1, the anchor
140 is in its recessed position, meaning that the pads 141 are substantially
within the plane of
the lower casing string 130. The pads 141 are not in contact with the upper
casing string 110
so as to facilitate the run-in of the apparatus 105. The pads 141 are
selectively actuated
either hydraulically or mechanically or both as is known in the art.
In the views of FIG. 6 and FIG. 7, the anchor 140 is in its extended position.
This means
that the pads 141 have been actuated to engage the inner surface of the upper
string of casing
110. This position allows the lower string of casing 130 to be fixed in place
while the lower
string of casing 130 is expanded into the wellbore 100.
An alternative embodiment for a torque anchor 250 is presented in Figure 9. In
this
embodiment, the torque anchor 250 defines a body having sets of wheels 254U
and 254L
radially disposed around its perimeter. The wheels 254U and 254L reside within
wheel
housings 253, and are oriented to permit axial (vertical) movement, but not
radial movement,
of the torque anchor 250. Sharp edges (not shown) along the wheels 254U and
254L aid in
inhibiting radial movement of the torque anchor 250. In the preferred
embodiment, four sets
of wheels 254U and 254L are employed to act against the upper casing 110 and
the lower
casing 130, respectively.
The torque anchor 250 is run into the wellbore 100 on the working string 115
along with the
expander tool 120 and the lower casing string 130. The run-in position of the
torque anchor
250 is shown in Figure 9. In this position, the wheel housings 253 are
maintained
essentially within the torque anchor body 250. Once the lower string of casing
130 has been
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lowered to the appropriate depth within the wellbore 100, the torque anchor
250 is activated.
Fluid pressure provided from the surface through the working tubular 115 acts
against the
wheel housings 253 to force the wheels 254C and 254L outward from the torque
anchor
body 250. Wheels 254C act against the inner surface of the upper casing string
130, while
wheels 254L act against the inner surface of the lower casing string 130. This
activated
position is depicted in Figure 10.
A rotating sleeve 251 resides longitudinally within the torque anchor 250. The
sleeve 251
rotates independent of the torque anchor body 250. Rotation is imparted by the
working
tubular 115. In turn, the sleeve provides the rotational force to rotate the
expander 120.
After the lower casing string 130L has been expanded into frictional contact
with the inner
wall of the upper casing string 110, the expander tool 120 is deactivated. In
this regard, fluid
pressure supplied to the pistons 175 is reduced or released, allowing the
pistons 175 to return
to the recesses 155 within the central body 150 of the tool 120. The expander
tool 120 can
then be withdrawn from the wellbore 100 by pulling the run-in tubular 115.
Although the invention has been described in terms of preferred embodiments as
set forth
above, it should be understood that these embodiments are illustrative only
and that the
claims are not limited to those embodiments. Those skilled in the art will be
able to make
modifications and alternatives in view of the disclosure which are
contemplated as falling
within the scope of the appended claims. In this respect; it is within the
scope of the present
inventions to expand a tubular having a scribe into the formation itself,
rather than into a
separate string of casing. In this embodiment, the formation becomes the
surrounding
tubular. Thus, the present invention has applicability in an open hole
environment.
