U.S. patent application number 12/100466 was filed with the patent office on 2009-10-15 for sealing between alignable windows for lateral wellbore drilling.
This patent application is currently assigned to HALLIBURTON ENERGY SERVICES, INC.. Invention is credited to Robert McCullough, Michael Rees, Shaun Renshaw, Henry Stoltz.
Application Number | 20090255687 12/100466 |
Document ID | / |
Family ID | 41162498 |
Filed Date | 2009-10-15 |
United States Patent
Application |
20090255687 |
Kind Code |
A1 |
McCullough; Robert ; et
al. |
October 15, 2009 |
Sealing Between Alignable Windows for Lateral Wellbore Drilling
Abstract
Sealing may be provided between alignable windows for lateral
wellbore drilling. A method for use with a lateral wellbore
includes the steps of: positioning a swellable seal material
between a closure device and a housing of a window assembly;
swelling the seal material to thereby prevent fluid transfer
through a window formed in a sidewall of the housing; and then
installing the window assembly in a parent wellbore. A lateral
wellbore system includes a window assembly with a window formed
through a sidewall of a generally tubular housing, and a swollen
seal material preventing fluid transfer through the window. A
window assembly includes a generally tubular housing having a
window formed through a sidewall of the housing, a closure device
having another window formed through a wall of the closure device;
and a swellable seal material which prevents fluid transfer between
the windows.
Inventors: |
McCullough; Robert; (Spruce
Grove, CA) ; Stoltz; Henry; (Edmonton, CA) ;
Rees; Michael; (Edmonton, CA) ; Renshaw; Shaun;
(Edmonton, CA) |
Correspondence
Address: |
SMITH IP SERVICES, P.C.
P.O. Box 997
Rockwall
TX
75087
US
|
Assignee: |
HALLIBURTON ENERGY SERVICES,
INC.
Carrollton
TX
|
Family ID: |
41162498 |
Appl. No.: |
12/100466 |
Filed: |
April 10, 2008 |
Current U.S.
Class: |
166/380 ;
166/184 |
Current CPC
Class: |
E21B 41/0035
20130101 |
Class at
Publication: |
166/380 ;
166/184 |
International
Class: |
E21B 33/124 20060101
E21B033/124 |
Claims
1. A lateral wellbore system, comprising: a window assembly
including a first window formed through a sidewall of a generally
tubular housing, and a swollen seal material preventing fluid
transfer through the first window.
2. The system of claim 1, wherein the seal material is swollen
prior to installation of the window assembly in a wellbore.
3. The system of claim 1, wherein the window assembly further
includes a second window formed through a wall of a closure device,
and wherein the seal material prevents fluid transfer between the
first and second windows.
4. The system of claim 3, wherein the second window is displaceable
into alignment with the first window, thereby permitting drilling
of a lateral wellbore through the aligned first and second
windows.
5. The system of claim 3, wherein the closure device is rotatable
to align the first and second windows.
6. The system of claim 3, wherein the closure device is
displaceable axially relative to the housing to align the first and
second windows.
7. The system of claim 1, wherein the window assembly further
includes a closure device displaceable to open the first window,
and wherein the seal material seals between the closure device and
the housing.
8. The system of claim 1, wherein the closure device is generally
tubular in shape and is received within an interior of the
housing.
9. A method for use with a lateral wellbore, the method comprising
the steps of: positioning a swellable seal material between a
closure device and a housing of a window assembly; swelling the
seal material to thereby prevent fluid transfer through a first
window formed in a sidewall of the housing; and then installing the
window assembly in a parent wellbore.
10. The method of claim 9, further comprising the step of
displacing the closure device relative to the housing, thereby
permitting fluid transfer through the window.
11. The method of claim 10, wherein the displacing step further
comprises rotating the closure device relative to the housing.
12. The method of claim 10, wherein the displacing step further
comprises axially displacing the closure device relative to the
housing.
13. The method of claim 10, wherein the displacing step further
comprises aligning the first window with a second window formed
through the closure device.
14. The method of claim 13, further comprising the step of drilling
the lateral wellbore through the aligned first and second
windows.
15. The method of claim 13, wherein the swelling step further
comprises preventing fluid transfer between the first and second
windows.
16. The method of claim 9, wherein the swelling step is performed
only prior to the installing step.
17. A window assembly for use in a subterranean well, the window
assembly comprising: a generally tubular housing having a first
window formed through a sidewall of the housing; a closure device
having a second window formed through a wall of the closure device;
and a swellable seal material which prevents fluid transfer between
the first and second windows.
18. The window assembly of claim 17, wherein the closure device is
generally tubular in shape and is received within an interior of
the housing.
19. The window assembly of claim 17, wherein the seal material is
swollen prior to installation of the window assembly in a
wellbore.
20. The window assembly of claim 17, wherein the second window is
displaceable into alignment with the first window, thereby
permitting drilling of a lateral wellbore through the aligned first
and second windows.
Description
BACKGROUND
[0001] The present disclosure relates generally to equipment
utilized and operations performed in conjunction with subterranean
wells and, in an embodiment described herein, more particularly
provides for sealing between alignable windows for lateral wellbore
drilling.
[0002] When a lateral or branch wellbore is drilled from a main or
parent wellbore, it is common practice to mill a window through the
sidewall of a casing or liner string in the parent wellbore in
order to initiate the lateral wellbore drilling process. However,
the milling process is very time consuming and expensive, and
entails certain risks.
[0003] Alternatively, the casing string could be provided with a
window pre-milled in its sidewall, with an easily drilled through
material (such as composite or aluminum, etc.) temporarily closing
off the window for circulating and cementing purposes. However,
such easily drilled through material is also relatively weak as
compared to the casing string, unless the material is made very
thick, which presents certain problems in the restricted confines
of a wellbore.
[0004] Another alternative is the use of an inner sleeve in the
casing string to temporarily close off a pre-milled window. The
inner sleeve could be displaced to uncover the pre-milled window
but, due to the complex geometry between the casing string and the
inner sleeve, obtaining a seal to prevent fluid transfer through
the window during circulating and cementing would be very
difficult.
[0005] Therefore, it will be appreciated that improvements are
needed in the art of providing windows for lateral wellbore
drilling.
SUMMARY
[0006] In the present specification, lateral wellbore window
methods and systems are provided which solve at least one problem
in the art. One example is described below in which a swellable
seal is used between alignable windows to thereby prevent fluid
transfer between the windows during operations such as circulating
and cementing. Another example is described below in which a window
which has been previously sealed using a swollen seal material is
then opened to permit drilling and/or accessing a lateral wellbore
through the window.
[0007] In one aspect, a lateral wellbore system includes a window
assembly with a window formed through a sidewall of a generally
tubular housing. A swollen seal material prevents fluid transfer
through the window.
[0008] In another aspect, a method for use with a lateral wellbore
includes the steps of: positioning a swellable seal material
between a closure device and a housing of a window assembly;
swelling the seal material to thereby prevent fluid transfer
through a window formed in a sidewall of the housing; and then
installing the window assembly in a parent wellbore.
[0009] In yet another aspect, a window assembly for use in a
subterranean well includes a generally tubular housing having a
window formed through a sidewall of the housing, and a closure
device having another window formed through a wall of the closure
device. A swellable seal material prevents fluid transfer between
the windows.
[0010] These and other features, advantages, benefits and objects
will become apparent to one of ordinary skill in the art upon
careful consideration of the detailed description of representative
embodiments hereinbelow and the accompanying drawings, in which
similar elements are indicated in the various figures using the
same reference numbers.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a schematic cross-sectional view of a lateral
wellbore drilling system and associated method which embody
principles of the present disclosure;
[0012] FIG. 2 is an enlarged scale schematic cross-sectional view
of a lateral wellbore window assembly usable in the system of FIG.
1;
[0013] FIG. 3 is a schematic partially cross-sectional view of a
method of operating the window assembly of FIG. 2;
[0014] FIG. 4 is a schematic cross-sectional view of the window
assembly in a closed configuration, taken along line 4-4 of FIG.
2;
[0015] FIG. 5 is a schematic cross-sectional view of the window
assembly in an open configuration;
[0016] FIG. 6 is an enlarged scale schematic detail of the window
assembly of FIG. 4; and
[0017] FIG. 7 is a schematic cross-sectional view of an alternate
construction of the window assembly.
DETAILED DESCRIPTION
[0018] It is to be understood that the various embodiments
described herein may be utilized in various orientations, such as
inclined, inverted, horizontal, vertical, etc., and in various
configurations, without departing from the principles of the
present disclosure. The embodiments are described merely as
examples of useful applications of the principles of the
disclosure, which are not limited to any specific details of these
embodiments.
[0019] In the following description of the representative
embodiments of the disclosure, directional terms, such as "above",
"below", "upper", "lower", etc., are used for convenience in
referring to the accompanying drawings. In general, "above",
"upper", "upward" and similar terms refer to a direction toward the
earth's surface along a wellbore, and "below", "lower", "downward"
and similar terms refer to a direction away from the earth's
surface along the wellbore.
[0020] Representatively illustrated in FIG. 1 is a lateral wellbore
drilling system 10 and associated method which embody principles of
the present disclosure. In the method, a parent wellbore 12 is
drilled, and then a lateral wellbore 14 is drilled extending
outwardly from the parent wellbore.
[0021] In order to facilitate drilling of the lateral wellbore 14,
the system 10 includes a window assembly 16 interconnected as part
of a casing string 18 installed in the parent wellbore 12. As used
herein, the term "casing string" is used to indicate a generally
tubular string used to provide a protective lining for a wellbore,
and can include at least those types of strings known as casing and
liner strings, which may be made of any type of material (such as
steel, other metals and alloys, plastics, composite materials,
etc.).
[0022] The window assembly 16 can include various features, such as
an azimuthally orienting latch profile 20, and other features not
specifically illustrated in the drawings. The latch profile 20
could be, for example, a Latch Coupling of the type available from
Sperry Drilling Services, and may be used to secure and orient
equipment such as a drilling whipstock (not shown) for drilling the
lateral wellbore 14.
[0023] As depicted in FIG. 1, the window assembly 16 also includes
a generally tubular housing 22 and a closure device 24. The closure
device 24 is used to initially close off a window 26 formed through
a sidewall of the housing 22.
[0024] When it is desired to drill (or otherwise obtain access to)
the lateral wellbore 14 from the parent wellbore 12, the closure
device 24 is displaced relative to the housing 22. In the example
illustrated in FIG. 1, this displacement results in alignment of
the window 26 in the housing 22 with another window 28 formed
through the closure device 24.
[0025] Preferably, the closure device 24 prevents fluid transfer
through the window 26 in the housing 22 while the casing string 18
is being installed in the parent wellbore 12, during fluid
circulation through the casing string, and during cementing of the
casing string in the parent wellbore. After the cementing
operation, the closure device 24 is displaced to open the window 26
and thereby permit drilling the lateral wellbore 14.
[0026] Note, however, that the various method steps and elements of
the system 10 described above and depicted in the drawings can be
altered to suit the particular circumstances or desired outcome of
an actual well operation. For example, it is possible that the
lateral wellbore 14 could be drilled prior to installing the casing
string 18 in the parent wellbore 12, it is not necessary for the
closure device 24 to include the window 28 which is alignable with
the window 26, it is not necessary for the casing string 18 to be
cemented in the parent wellbore, the closure device is not
necessarily internal to the housing 22, the closure device is not
necessarily tubular in shape, the latch profile 20 could be
positioned above the window 26, etc. Thus, it should be clearly
understood that the principles of the present disclosure are not
limited to the details of the system 10 and associated methods
described herein.
[0027] Referring additionally now to FIG. 2, an enlarged scale
cross-sectional view of the window assembly 16 is representatively
illustrated. In this view, further details of the window assembly
16 may be seen.
[0028] Note that the windows 26, 28 are aligned with each other in
the open configuration of the window assembly 16 depicted in FIG.
1, but the windows are not aligned with each other in the closed
configuration of the window assembly depicted in FIG. 2. Thus, in
the closed configuration, the closure device 24 prevents fluid
transfer through the window 26, and in the open configuration, the
closure device permits fluid transfer through the window 26.
[0029] In this example of the window assembly 16, the closure
device 24 is rotated about a longitudinal axis 30 of the window
assembly in order to displace the closure device between its open
and closed positions. As described more fully below, the latch
profile 20 and recesses 32 formed in the interior of the closure
device 24 facilitate this rotation of the closure device, but other
means may be used to displace the closure device if desired.
[0030] Preferably, the window assembly 16 is installed in the
parent wellbore 12 with the closure device 24 in its closed
position preventing fluid transfer through the window 26. In this
manner, fluid may be circulated through the entire casing string 18
during its installation. Also, when the casing string 18 is
properly positioned in the wellbore 12, it may be cemented in place
by flowing the cement through the casing string and into the
annulus between the casing string and the wellbore.
[0031] After the cementing operation, the closure device 24 is
preferably displaced to its open position. With the windows 26, 28
aligned, the lateral wellbore 14 can be drilled through the windows
(e.g., by installing a drilling whipstock in the window assembly 16
and deflecting a drill string from within the casing string 18
outward through the windows), access to the lateral wellbore is
permitted, etc.
[0032] Referring additionally now to FIG. 3, a schematic partially
cross-sectional view of the system 10 and associated method is
representatively illustrated. In this view, one technique for
rotating the closure device 24 between its open and closed
positions is depicted.
[0033] A service-tool 34 is conveyed into the window assembly 16 on
a tubular string 36. A latch 38 at a lower end of the service tool
34 engages the latch profile 20, thereby axially and azimuthally
aligning the service tool with the window assembly 16. This
alignment positions dogs or lugs 40 on the service tool 34 opposite
the recesses 32 in the closure device 24 (see FIG. 2).
[0034] Pressure is applied to the tubular string 36 to cause the
lugs 40 to extend outward into engagement with the recesses 32. The
tubular string 36 and service tool 34 above the latch 38 are then
rotated to thereby rotate the closure device 24. When the windows
26, 28 are properly aligned with each other, an indication of this
alignment will be provided by, for example, an increased torque in
the tubular string 36 and/or the service tool 34 causing a release
of pressure from the tubular string, etc.
[0035] When the applied pressure is released from the tubular
string 36, the lugs 40 will withdraw from the recesses 32, and the
service tool 34 can be retrieved from the well. Latches, snap
rings, detents, etc. can be provided in the window assembly 16 to
retain the closure device 24 in its open position.
[0036] Referring additionally now to FIG. 4, an enlarged scale
cross-sectional view of the window assembly 16 is representatively
illustrated, taken along line 4-4 of FIG. 2. In this view, the
window assembly 16 is in its closed configuration, with the closure
device 24 preventing fluid transfer through the window 26.
[0037] Referring additionally now to FIG. 5, the window assembly 16
is depicted in its open configuration, with the windows 26, 28
aligned and permitting fluid transfer through the windows between
the interior and exterior of the window assembly. Note that the
closure device 24 is rotated 180 degrees about the longitudinal
axis 30 of the window assembly 16 between its closed and open
positions. Of course, depending on the geometry of the window
assembly 16, other amounts of rotation of the closure device 24 may
be used if desired.
[0038] In one unique aspect of the window assembly 16, a swellable
seal material 42 is positioned in the annular space between the
closure device 24 and housing 22. The seal material 42 is also
positioned in such a way as to prevent fluid transfer between the
windows 26, 28 when the closure device 24 is in its closed
position.
[0039] An enlarged scale detailed view of the seal material 42
between the housing 22 and closure device 24 is representatively
illustrated in FIG. 6. In this view, it may be seen that the seal
material 42 effectively closes off the annular space between the
housing 22 and closure device 24.
[0040] In the illustrated example, the seal material 42 is a
swellable material which swells in response to contact with a
certain fluid. The term "swell" and similar terms (such as
"swellable") are used herein to indicate an increase in volume of a
seal material. Typically, this increase in volume is due to
incorporation of molecular components of the fluid into the seal
material itself, but other swelling mechanisms or techniques may be
used, if desired.
[0041] The seal material 42 is preferably adhered to an exterior
surface of the closure device 24. When the seal material 42 swells
in the window assembly 16, it preferably expands radially outward
into contact with an inner surface of the housing 22. This swelling
of the seal material 42 is preferably accomplished prior to
installing the window assembly 16 in the wellbore 12.
[0042] Note that swelling is not the same as expanding, although a
seal material may expand as a result of swelling. For example, in
some conventional packers, a seal element may be expanded radially
outward by longitudinally compressing the seal element, or by
inflating the seal element. In each of these cases, the seal
element is expanded without any increase in volume of the seal
material of which the seal element is made. Thus, in these
conventional packers, the seal element expands, but does not
swell.
[0043] The fluid which causes swelling of the swellable material
could be water and/or hydrocarbon fluid (such as oil or gas). The
fluid could be a gel or a semi-solid material, such as a
hydrocarbon-containing wax or paraffin which melts when exposed to
increased temperature. The fluid could cause swelling of the
swellable material due to passage of time.
[0044] Various swellable materials are known to those skilled in
the art, which materials swell when contacted with water and/or
hydrocarbon fluid, so a comprehensive list of these materials will
not be presented here. Partial lists of swellable materials may be
found in U.S. Pat. Nos. 3,385,367 and 7,059,415, and in U.S.
Published Application No. 2004-0020662, the entire disclosures of
which are incorporated herein by this reference.
[0045] The swellable material may have a considerable portion of
cavities which are compressed or collapsed. When exposed to higher
pressure, the material is expanded by the cavities filling with
fluid.
[0046] This type of swellable material might be used where it is
desired to expand the material in the presence of gas rather than
oil or water. A suitable swellable material is described in
International Application No. PCT/NO2005/000170 (published as WO
2005/116394), the entire disclosure of which is incorporated herein
by this reference.
[0047] It should, thus, be clearly understood that any swellable
material which swells when contacted by any type of fluid may be
used in keeping with the principles of the invention. Preferably,
the seal material 42 used in the window assembly 16 is swellable in
response to contact with a hydrocarbon fluid.
[0048] It will be appreciated that, due to the complex geometry
between the housing 22 and the closure device 24, it would be very
difficult to use a conventional seal (such as an o-ring) to prevent
fluid transfer between the windows 26, 28 in the closed
configuration of the window assembly 16. In contrast, the swellable
seal material 42 is able to conform to the complex geometry and any
surface irregularities on the exterior surface of the closure
device 24 and on the inner surface of the housing 22.
[0049] In addition, the seal material 42 can serve to centralize
the closure device 24 within the housing 22. In one embodiment, the
exterior surface of the closure device 24 may be completely covered
with the seal material 42. In other embodiments, the seal material
42 could extend only about the window 26 when the closure device 24
is in its closed position. The seal material 42 may be shaped and
positioned in various different ways in keeping with the principles
of this disclosure.
[0050] Referring additionally now to FIG. 7, an alternate
construction of the window assembly 16 is representatively
illustrated. In this construction, the closure device 24 is
displaced axially, instead of rotationally, to align the windows
26, 28.
[0051] As depicted in FIG. 7, the closure device 24 is in its
closed position preventing fluid transfer through the window 26.
However, when the closure device 24 is displaced downward relative
to the housing 22 (e.g., in a direction parallel to the
longitudinal axis 30 of the window assembly), the windows 26, 28
will be aligned, thereby permitting fluid transfer between the
windows.
[0052] The swellable seal material 42 in the example of FIG. 7
extends completely around the closure device 24. The seal material
42 prevents fluid transfer between the windows 26, 28 when the
closure device 24 is in its closed position
[0053] Note that it is not necessary for the closure device 24 to
have a generally tubular shape, or for the window 28 to be formed
through a wall of the closure device. For example, the closure
device 24 could instead close off the window 26 without having a
tubular shape, or the closure device could be a sleeve without a
window in its sidewall (in which case the closure device would not
cover or be positioned opposite the window 26 in the open position
of the closure device).
[0054] Note, also, that any type of displacement may be used to
move the closure device 24 between its closed and open positions
(such as, axial, rotational, helical, reciprocal or any other
displacement). The closure device 24 could be retrieved from within
the housing 22, instead of remaining in the housing after the
closure device is displaced to its open position. Thus, it should
be clearly understood that the present disclosure is not limited to
any of the particular details of the window assembly 16 described
herein.
[0055] It may now be fully appreciated that the system 10, its
associated methods and the window assembly 16 provide significant
advances in the art of drilling lateral wellbores. Specifically, a
window is provided in a casing string in a parent wellbore for
drilling and accessing a lateral wellbore, without the need for
milling through a sidewall of the casing string, but with enhanced
sealing to permit circulation and cementing prior to opening the
window, and in a manner which allows the window to be conveniently
opened.
[0056] In particular, a lateral wellbore system 10 is provided
which includes a window assembly 16 having a window 26 formed
through a sidewall of a generally tubular housing 22, and with a
swollen seal material 42 preventing fluid transfer through the
window. The seal material 42 is preferably swollen prior to
installation of the window assembly 16 in a wellbore 12.
[0057] The window assembly 16 may further include another window 28
formed through a sidewall of a closure device 24, and the seal
material 42 may prevent fluid transfer between the windows 26,
28.
[0058] The window 28 may be displaceable into alignment with the
window 26, thereby permitting drilling of a lateral wellbore 14
through the aligned windows 26, 28 The closure device 24 may be
rotatable to align the windows 26, 28. The closure device 24 may be
displaceable axially relative to the housing 22 to align the
windows 26, 28.
[0059] The window assembly 16 may include the closure device 24
which is displaceable to open the window 26, with the seal material
42 sealing between the closure device 24 and the housing 22. The
closure device 24 may be generally tubular in shape and may be
received within an interior of the housing 22.
[0060] A method for use with a lateral wellbore 14 is provided
which includes the steps of: positioning a swellable seal material
42 between a closure device 24 and a housing 22 of a window
assembly 16; swelling the seal material 42 to thereby prevent fluid
transfer through a window 26 formed in a sidewall of the housing
22; and then installing the window assembly 16 in a parent wellbore
12.
[0061] The method may also include the step of displacing the
closure device 24 relative to the housing 22, thereby permitting
fluid transfer through the window 26.
[0062] The displacing step may include rotating the closure device
24 relative to the housing 22. The displacing step may include
axially displacing the closure device 24 relative to the housing
22.
[0063] The displacing step may include aligning the window 26 with
another window 28 formed through the closure device 24. The method
may include the step of drilling the lateral wellbore 14 through
the aligned windows 26, 28. The swelling step may include
preventing fluid transfer between the windows 26, 28.
[0064] The seal material swelling step may be performed only prior
to the window assembly installing step.
[0065] Also provided by the present disclosure is a window assembly
16 for use in a subterranean well. The window assembly 16 includes
a generally tubular housing 22 having a window 26 formed through a
sidewall of the housing, a closure device 24 having another window
28 formed through a wall of the closure device, and a swellable
seal material 42 which prevents fluid transfer between the windows
26, 28.
[0066] Of course, a person skilled in the art would, upon a careful
consideration of the above description of representative
embodiments, readily appreciate that many modifications, additions,
substitutions, deletions, and other changes may be made to these
specific embodiments, and such changes are within the scope of the
principles of the present disclosure. Accordingly, the foregoing
detailed description is to be clearly understood as being given by
way of illustration and example only, the spirit and scope of the
present invention being limited solely by the appended claims and
their equivalents.
* * * * *