U.S. patent application number 11/484239 was filed with the patent office on 2007-02-15 for whipstock liner.
Invention is credited to Christopher A. Pratt.
Application Number | 20070034384 11/484239 |
Document ID | / |
Family ID | 37259245 |
Filed Date | 2007-02-15 |
United States Patent
Application |
20070034384 |
Kind Code |
A1 |
Pratt; Christopher A. |
February 15, 2007 |
Whipstock liner
Abstract
A liner system has a setting collar at one end and is adapted
for insertion into a well bore. The setting collar is adapted to
couple with a liner running tool. A whipstock surface is provided
on the setting collar and adapted to deflect a drilling string in
drilling a lateral well bore off of the first well bore. A method
of forming a well system includes forming a first well bore;
installing a first liner in the first well bore, the first liner
having a first whipstock surface adapted to deflect a drilling
string; and then forming a second well bore extending from the
first well bore by deflecting a drilling string through contact
with the first whipstock surface.
Inventors: |
Pratt; Christopher A.;
(Cochrane, CA) |
Correspondence
Address: |
FISH & RICHARDSON P.C.
P.O. BOX 1022
MINNEAPOLIS
MN
55440-1022
US
|
Family ID: |
37259245 |
Appl. No.: |
11/484239 |
Filed: |
July 10, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60697638 |
Jul 8, 2005 |
|
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|
Current U.S.
Class: |
166/380 ;
166/117.6; 166/50 |
Current CPC
Class: |
E21B 43/10 20130101;
E21B 7/061 20130101; E21B 41/0035 20130101 |
Class at
Publication: |
166/380 ;
166/050; 166/117.6 |
International
Class: |
E21B 7/06 20060101
E21B007/06 |
Claims
1. A device comprising: a liner setting collar, the setting collar
adapted to couple with a liner running tool, the setting collar
further adapted to attach to a liner tubing; and a whipstock
surface on the setting collar adapted to deflect a drilling
string.
2. The device of claim 1 further comprising a length of liner
tubing.
3. The device of claim 2 wherein the length of liner tubing and
liner setting collar are coupled using a threaded connection.
4. The device of claim 2 wherein a smallest inner diameter of the
setting collar about the whipstock surfaces is smaller than a
smallest inner diameter of the liner tubing.
5. The device of claim 2 wherein the liner tubing is selected from
the group consisting of solid liner tubing, apertured liner tubing,
and expanded/expandable liner tubing.
6. The device of claim 1 wherein the whipstock surface is at least
partially defined by additional material coupled to the end of the
setting collar.
7. The device of claim 1 wherein the whipstock surface is defined
at an end of the setting collar and wherein at least a portion of
the whipstock surface is at an acute angle to a longitudinal axis
of the setting collar.
8. The device of claim 7 wherein the angle is between 2 and 45
degrees.
9. The device of claim 1 wherein the whipstock surface is defined
by an end portion of setting collar sidewalls.
10. The device of claim 9 wherein the end portion of the setting
collar sidewalls has a first sidewall thickness than is greater
than a second sidewall thickness of a length of liner tubing
coupled to the setting collar.
11. The device of claim 1 wherein the whipstock surface and setting
collar are constructed as one piece of material.
12. The device of claim 1 wherein the setting collar is adapted to
remain attached to the liner tubing while the setting collar is in
a well bore.
13. A liner system comprising: a first length of liner tubing
extending from a first end to a second end; and a tubular body
adapted to couple with a liner running tool, the tubular body
including a whipstock surface adapted to deflect a drilling string;
wherein the tubular body is coupled to the first end of the first
length of liner tubing.
14. The liner system of claim 13 wherein the tubular body is
coupled to the first length of liner tubing using a threaded
connection.
15. The liner system of claim 14 wherein a smallest inner diameter
of the tubular body about the whipstock surfaces is smaller than a
smallest inner diameter of the liner tubing.
16. The liner system of claim 13 further comprising a second length
of liner tubing, the second length of liner tubing attached to the
second end of the first length of liner tubing.
17. The liner system of claim 13 wherein the liner tubing is
selected from the group consisting of solid liner tubing, apertured
liner tubing, and expanded/expandable liner tubing.
18. The liner system of claim 13 wherein the whipstock surface is
defined at an end of the tubular body and wherein at least a
portion of the whipstock surface is at an acute angle to a
longitudinal axis of the setting collar.
19. The liner system of claim 18 wherein the angle is approximately
3 degrees.
20. A method of forming a well system, the method comprising:
forming a first well bore; installing a first liner in the first
well bore, the first liner having a first whipstock surface adapted
to deflect a drilling string; and then forming a second well bore
extending from the first well bore by deflecting a drilling string
through contact with the first whipstock surface.
21. The method of claim 20 wherein the first liner comprises a
first setting collar attached to a length of liner tubing.
22. The method of claim 21 wherein the first setting collar is
adapted to couple with a liner running tool.
23. The method of claim 21 wherein installing a liner comprises
orienting the first whipstock surface by rotating the first setting
collar.
24. The method of claim 23 wherein rotating the first setting
collar comprises engaging the first setting collar with torque fins
on the liner running tool.
25. The method of claim 20 further comprising installing a second
liner in the second well bore, the second liner having a second
whipstock surface adapted to deflect a drilling string.
26. The method of claim 25 further comprising forming a third well
bore by deflecting a drilling string through contact with the
second whipstock surface.
27. The method of claim 26 wherein the third well bore extends from
the first well bore.
Description
[0001] This application claims the benefit of U.S. Provisional
Application No. 60/697,638, filed Jul. 8, 2005.
TECHNICAL FIELD
[0002] The present invention relates to well bore patterns, and
more particularly to forming one or more lateral well bores off a
first drilled well bore.
BACKGROUND
[0003] In some wells, a liner can be used to prevent the wall of a
well bore from caving or to filter solids (particulate or larger)
from entering the well bore. Liners can also be run to isolate one
or more subterranean zones, for example, to protect fresh-water
formations, isolate a zone of lost returns or isolate formations
with significantly different pressure gradients. Liners are usually
manufactured from plain carbon steel, but may be specially
fabricated of stainless steel, aluminum, titanium, fiberglass and
other materials.
[0004] In some cases, it is desirable to drill a second well bore
from a first well bore, i.e., a lateral. One manner of drilling the
second well bore involves a whipstock. Whipstocks include an
inclined wedge placed in a well bore that forces the drill bit to
start drilling in a direction away from the well bore axis. The
whipstock has a hard surface so that the bit will preferentially
drill through either casing or rock rather than the whipstock
itself. Whipstocks may be oriented in a particular direction if
needed, or placed into a well bore blind, with no regard to the
direction they face. Most whipstocks are set on the bottom of the
hole or on top of a high-strength cement plug or a whipstock anchor
packer (e.g., a special-purpose packer placed in the casing to
permit a sidetrack operation), but some are set in an open well
bore. When the operations involving the whipstock are complete, the
whipstock is often retrieved from the well bore.
SUMMARY
[0005] The present invention relates to well bore patterns, and
more particularly to forming one or more lateral well bores off a
first drilled well bore.
[0006] In one aspect, a device includes a liner having a setting
collar at one end, the setting collar adapted to couple with a
liner running tool, the setting collar further adapted to attach a
liner tubing; and a whipstock surface on the setting collar adapted
to deflect a drilling string.
[0007] In another aspect, a liner system includes: a first length
of liner tubing extending from a first end to a second end; and a
setting collar adapted to couple with a liner running tool, the
setting collar including a whipstock surface adapted to deflect a
drilling string. The setting collar is coupled to the first end of
the first length of liner tubing.
[0008] In another aspect, a method of forming a well system
includes: forming a first well bore; installing a first liner in
the first well bore, the first liner having a first whipstock
surface adapted to deflect a drilling string; and then forming a
second well bore extending from the first well bore by deflecting a
drilling string through contact with the first whipstock
surface.
[0009] Embodiments can include one or more of the following
features.
[0010] In some embodiments, the liner includes a length of liner
tubing. In some instances, a threaded connection couples the
setting collar to the length of liner tubing. In some instances, a
first inner diameter of the setting collar at least as large as a
second inner diameter of the liner tubing. In some instances, the
liner tubing is selected from the group consisting of solid liner
tubing, apertured liner tubing, and other types of liner
tubing.
[0011] In some embodiments, the whipstock surface is at least
partially defined by additional material coupled to the end of the
setting collar.
[0012] In some embodiments, the whipstock surface is defined at an
end of the setting collar and is formed at a an angle to a
longitudinal axis of the setting collar. In some instances, the
angle is between 2 and 45 degrees (e.g., about 3 degrees, between
10 and 20 degrees, and/or about 15 degrees).
[0013] In some embodiments, the whipstock surface is defined by an
end portion of setting collar sidewalls. In some instances, the end
portion of the setting collar sidewalls has a first sidewall
thickness than is greater than a second sidewall thickness of a
second portion of the setting collar sidewalls. In some instances,
the first sidewall thickness is greater than a third sidewall
thickness of a length of liner tubing coupled to the setting
collar. A threaded connection can couple the setting collar to the
first length of liner tubing. A first inner diameter of the setting
collar can be at least as large as a second inner diameter of the
liner tubing.
[0014] In some embodiments, liner systems also include a second
length of liner tubing, the second length of liner tubing attached
to the second end of the first length of liner tubing.
[0015] In some embodiments, the first liner includes a first
setting collar (e.g., a setting collar is adapted to couple with a
liner running tool) attached to a length of liner tubing. In some
instances, installing a liner includes orienting the first
whipstock surface by rotating the first setting collar. Rotating
the first setting collar can include engaging the first setting
collar with torque fins on the liner running tool.
[0016] In some embodiments, methods also include installing a
second liner in the second well bore, the second liner having a
second whipstock surface on the second setting collar adapted to
deflect a drilling string. In some instances, methods also include
forming a third well bore by deflecting a drilling string through
contact with the second whipstock surface. The third well bore can
extend from the first well bore
[0017] An advantage of one or more implementations is that the
whipstock surface is integrated with the setting collar of the
liner. Thus, a separate whipstock need not be provided. As the
whipstock surface resides at the end of a liner, the spacing
between laterals is not limited by the size of a separate whipstock
tool. In other words, multiple whipstock surfaces can be positioned
closer to one another in a well bore than multiple separate
whipstocks, because the whipstock surfaces residing at the end of a
liner take up less space. As a result, multiple lateral well bores
can be diverted from the original at more closely spaced intervals.
For example, one liner can be positioned adjacent, and in some
instances within a few inches of or in contact with, the whipstock
surface of another liner. This allows the first liner to
communicate flow into the second string and reduces the chance of
the well bore plugging if it collapses. In some implementations,
the whipstock surface maintains its position and orientation within
the well bore by reacting against the liner tubing which may be
frictionally held in the well bore. In some implementations, there
are no moving parts associated with a gripping mechanism to fail.
Also, because of the lack of moving parts, the system is
inexpensive to construct.
[0018] Another advantage of one or more implementations is
increased drilling efficiency because of a reduced number of trips
into and out of the well bore. For example, a well system with
single lateral well bore diverging from a horizontal well bore can
be formed with only three trips into and out of the well system
using the devices, systems, and methods described above. First, a
drill string can be used to form the horizontal well bore extending
from an articulated well bore. Second, after the drill string is
withdrawn, a working string can be used to install a liner with a
setting collar with a whipstock surface in the horizontal well
bore. The liner is positioned such that the setting collar is
disposed at the point the lateral well bore will be formed. Third,
after the working string is withdrawn, the drill string travels
back through the articulated well bore and horizontal well bore
until it is deflected by the whipstock surface on the setting
collar of the liner in the horizontal well bore. After forming the
lateral well bore, the drill string is withdrawn. In contrast, use
of a separate whipstock requires additional trips into and out of
the well bore by the working string to place and retrieve the
whipstock (e.g., after the liner is installed in the horizontal
well bore and after the lateral well bore is formed).
[0019] The details of one or more embodiments of the invention are
set forth in the accompanying drawings and the description below.
Other features, objects, and advantages of the invention will be
apparent from the description and drawings, and from the
claims.
DESCRIPTION OF DRAWINGS
[0020] FIG. 1 is a schematic partial side cross-sectional view of
an illustrative liner system constructed in accordance with the
concepts described herein.
[0021] FIG. 2 is a schematic side cross-sectional view of an
illustrative well system constructed in accordance with the
concepts described herein.
[0022] FIG. 3 is a schematic plan view of the illustrative well
system of FIG. 1.
[0023] FIG. 4 is a schematic side cross-sectional view of the
illustrative well system of FIG. 2 during its construction in
accordance with the concepts described herein.
[0024] FIG. 5 is a schematic side cross-sectional view of the
illustrative well system of FIG. 2 during its construction in
accordance with the concepts described herein.
[0025] Like reference symbols in the various drawings indicate like
elements.
DETAILED DESCRIPTION
[0026] Referring to FIG. 1, an illustrative liner system 10
constructed in accordance with the concepts described herein is
depicted depending from a liner running tool 12 in a well bore 14.
The illustrative liner system 10 includes a tubular setting collar
16 coupled to one or more lengths of liner tubing 18. In one
instance, the tubular setting collar 16 is coupled to an adjacent
length of liner tubing 18 with a threaded connection. The liner
tubing 18 can be one or more lengths of solid tubing, apertured
tubing, and other types of liner tubing.
[0027] Although there are numerous liner running tools that can be
used in accordance with the concepts described herein, an
illustrative liner running tool 12 is depicted in FIG. 1. The
illustrative liner running tool 12 includes a body portion 28 that
is adapted to couple to (and depend from) a working string 26. The
body portion 28 is at least partially received within the interior
of the setting collar 16. One or more radially
extendable/retractable dogs 20 are positioned about the body
portion 28. In the extended position, the dogs 20 protrude from the
exterior of the body portion 28. FIG. 1 depicts the dogs 20
extended into a corresponding groove 22 in the interior of the
setting collar 16. The dogs 20 abut a downwardly facing shoulder 24
of the groove 22 and support the weight of liner system 10. When
retracted, the dogs 20 reside out of the groove 22. In one
instance, the dogs 20 are biased to the radially extended position,
and can be retracted by application of hydraulic pressure through
the interior of the liner running tool 12. Thus, to release the
dogs 20 from the groove 22 and the liner running tool 12 from the
setting collar 16, hydraulic pressure is applied through the
interior of liner running tool 12. In other instances, the dogs 20
may be extended or retracted by one or more of mechanical
manipulation via the working string 26, hydraulic pressure,
electric power or other mechanism. When the dogs 20 are released
from the groove 22, the liner running tool 12 can be withdrawn from
the setting collar 16.
[0028] The liner running tool 12 further includes one or more
extendable/retractable torque fins 28 positioned about the body
portion 28. In the extended position, the torque fins 28 protrude
from the exterior of the body portion 28. FIG. 1 depicts a torque
fin 28 extended into a corresponding longitudinally (with respect
to the setting collar 16) oriented slot 30 in the interior of the
setting collar 16. The number of slots 30 can correspond to the
number of torque fins 28. When the liner running tool 12 is rotated
relative to the setting collar 16, the torque fin 28 abuts one or
the other sidewall 32 of the slot 30, and cause the setting collar
16 to rotate with the liner running tool 12. When retracted, the
torque fins 28 reside out of the slots 30, and the liner running
tool 12 can rotate in the setting collar 16. In one instance, the
torque fins 28 are spring biased to the radially extended position,
and include a sloped upper surface 34. As the liner running tool 12
is drawn upward in the setting collar 16, the sloped upper surface
34 bears against the upper wall 36 of the slot 30 and wedges the
torque fins 28 to the retracted position and out of the slots 30.
Thereafter the running tool 12 may be withdrawn from the setting
collar 16. In other instances, the torque fins 28 may be extended
or retracted by one or more of mechanical manipulation via the
working string 26, hydraulic pressure, electric power or other
mechanism.
[0029] The tubular setting collar 16 has a whipstock surface 40 on
its upper end. As is discussed in more detail below, the whipstock
surface 40 operates to deflect drilling operations to deviate from
a longitudinal axis of the setting collar 16. The longitudinal axis
of the setting collar 16 is substantially parallel or coincides
with the longitudinal axis of a portion of the well bore (e.g. well
bore 14) in which the setting collar 16 resides. The whipstock
surface 40 is defined at the end of the setting collar 16 and
formed at a specified angle .theta. to the longitudinal axis of the
setting collar 16. The specified angle .theta. is selected based on
the desired angle of departure of the drilling operations from the
longitudinal axis of the well bore. In some instances, at least a
portion of the whipstock surface is at an acute angle to a
longitudinal axis of the setting collar. For example, in one
instance, the whipstock surface 40 is formed at a 15.degree. angle
to the longitudinal axis of the well bore 14. In other instances,
the whipstock surface 40 can be formed at shallower or steeper
angles. For example, in another instance, the whipstock surface 40
is formed at a 3.degree. angle to the longitudinal axis of the well
bore 14. In certain implementations, the whipstock surface 40 has
two or more angles. For example, in one instance, the whipstock
surface 40 has an initial angle of 15.degree. and subsequently an
angle of 3.degree. to the longitudinal axis of the well bore
14.
[0030] In certain implementations, the whipstock surface 40 is
defined by the end walls 42 of the setting collar 16. Accordingly,
the whipstock is integral to the liner tubing 18 in contrast to a
conventional whipstock that is coupled to an interior of a liner or
casing. To this end, the setting collar 16 may have an increased
sidewall thickness 44 about the end walls 42. In some instances,
this sidewall thickness 44 is greater than the sidewall thickness
46 of the liner tubing 18. In one instance, the setting collar 16
has an outer diameter approximately equal to the outer diameter of
a stock sized collar for use with the size of liner tubing 18 used,
but has an inside diameter sized to receive a stock size liner
running tool 12 for running a smaller size of liner tubing. For
example, for a system with 4.5 inch (114.3 mm) nominal outer
diameter liner tubing 18, the setting collar 16 can have 5.0 inch
(127 mm) nominal outer diameter (i.e. approximately equal to the
standard size casing collar), but have an inner diameter sized to
accept a stock liner running tool 12 configured for running a 3.5
inch (88.9 mm) nominal outer diameter liner tubing 18. In other
implementations, additional material may be coupled to the end of
the setting collar 16 to define a whipstock surface 40. The inner
diameter of the setting collar 16 is equal to or greater than the
inner diameter of the liner tubing 18. For example, in some
instances, a smallest inner diameter of the setting collar is at
least as large as a smallest inner diameter of the liner
tubing.
[0031] In certain implementations, the whipstock surface 40 can be
harder than the remainder of the setting collar 16. In one
instance, the whipstock surface 40 is steel that has been surface
hardened. In other instances, a hardened surface is deposited on
the whipstock surface 40 in addition to, or as an alternative to,
the surface hardening.
[0032] In some embodiments, the setting collar 16 and whipstock
surface 40 are of one-piece construction (e.g., the whipstock
surface is formed directly on the setting collar). In some
embodiments, the setting collar 16 and whipstock surface 40 are of
unitary multi-piece construction (e.g., the whipstock surface can
be formed on a separate work piece that fixedly attached to the
setting collar so that the setting collar and whipstock-bearing
work piece are not separable downhole.
[0033] The liner running tool 12 enables the illustrative liner
system 10 to be placed in a well bore, such as well bore 14. To
this end, the liner running tool 12 is coupled to a working string
26 and received in the setting collar 16 of the illustrative liner
system 10. The dogs 20 are changed to the extended position to be
received in the groove 22 of the setting collar 16. If biased to
the extended position, the dogs 20 automatically snap into the
groove 22. The liner system 10 is thereafter supported from the
liner running tool 12, as the dogs 20 bear against the shoulder 24
of groove 22. Additionally, the torque fins 28 of the liner running
tool 12 can be aligned with the slots 30 in the setting collar 16.
When changed to the extended position, the torque fins 28 are
received in the slots 30 and torsionally lock the liner running
tool 12 to the setting collar 16 (and thus illustrative liner
system 10) to rotate together. If biased to the extended position,
the torque fins 28 automatically snap into the slots 30 when
aligned with the slots 30. Thereafter, the illustrative liner
system 10 depends from the liner running tool 12, and is run into a
well bore, such as well bore 14 as is depicted in FIG. 4, on the
working string 26. Once in the desired location within the well
bore and/or as the illustrative liner system is moved into location
in the well bore, the illustrative liner system 10 can be
rotationally oriented to align the whipstock surface 40 to deflect
drilling operations in the desired orientation by rotating the
liner running tool 12 via the working string 26. The liner running
tool 12 can then be released from the illustrative liner system 10
by actuating the dogs 20 to the retracted position (for example, by
applying hydraulic pressure through the working string 26 into the
interior of the liner running tool 12), actuating the torque fins
28 to the retracted position (for example, by wedging sloped upper
surface 34 against the upper wall of the slot 36), and withdrawing
the liner running tool 12 from the setting collar 16. The setting
collar 16 and whipstock surface 40 need not be attached (for
example, by slips) to the wall of the well bore, because they are
affixed to the liner tubing 18. The liner tubing 18, in turn, is
frictionally held in the well bore 14. However, in some instances,
the setting collar can include a liner hanger and/or can include a
gripping assembly (e.g., slips). The gripping assembly is actuable
into gripping engagement with a wall of the well bore to anchor the
setting collar, and liner tubing, in the well bore.
[0034] FIG. 2 depicts an illustrative well system 100 constructed
in accordance with the concepts described herein. The well system
100 includes a surface well bore 110 and one or more secondary well
bores 112 (three shown) formed near to, and in some instances
adjacent to, one another. The secondary well bores 112 define a
well bore pattern. The surface well bore 110 extends either
directly from the surface 116, or extends from another bore, pit,
shaft, fissure, cavity, or other feature (not specifically shown)
in communication with the surface 116. In FIG. 2, the surface well
bore 110 is depicted as an articulated well bore having a first
portion 118, a second portion 120, and a curved portion 122
connecting the first portion 118 and the second portion 120. The
second portion 120 extends into a subterranean zone 114. Although
depicted as being substantially vertical, some or all of the first
portion 118 may be slanted, undulating, or otherwise not vertical.
Likewise, although depicted as being substantially horizontal, some
or all of the second portion 120 may be slanted, undulating, or
otherwise not horizontal. A casing 124 or other type of liner
tubing may optionally be provided through at least a portion of the
surface well bore 110. The casing 124 may be provided, for example,
to prevent collapse of the earth about the well bore 110 and/or to
isolate other subterranean zones through which the well bore 110
may pass from communicating with the well bore 110. FIG. 3 depicts
the casing 124 extending from a wellhead 136 about the surface 116
downward through the first portion 118, curved portion 122 and into
the second portion 120. In other instances, the casing 124 can
extend solely in the first portion 118 or through the first portion
118 and into the curved portion 122.
[0035] In one instance, the subterranean zone 114 is a coal seam.
However, the concepts described herein are applicable to other
types of subterranean zones. For example, the subterranean zone 114
can be an oil and gas formation, water producing formation, or
other type of formation.
[0036] The illustrative well system 100 further includes a cavity
126 (an enlarged cavity is shown) formed in or near to the
subterranean zone 114. Other well systems formed according to the
concepts described herein can omit the cavity 126. In one instance,
the cavity 126 is formed through a surface communicating cavity
well bore 128 extending either directly from the surface 116, or
from another bore, pit, shaft, fissure, cavity, or other feature
(not specifically shown) in communication with the surface 116.
Therefore, the cavity 126 corresponds to the location of an
intersection between the surface well bore 110 and the cavity well
bore 128. The cavity 126 may have a larger transverse dimension
than the cavity well bore 128, as is shown in FIG. 2, or may have a
transverse dimension that is smaller than or substantially equal to
the transverse dimension of the cavity well bore 128. Some or all
of the cavity well bore 128 may be provided with a casing 130 or
other type of liner tubing. The casing 130 may be provided, for
example, to prevent collapse of the earth about the well bore 128
and/or to isolate other subterranean zones through which the well
bore 128 may pass from communicating with the well bore 128. In
FIG. 2, the casing 130 is shown extending from a wellhead 132 at
the surface 116 to the cavity 126. The casing 130 may also be
omitted. The cavity 126 can also optionally be provided with a sump
134 that extends downward beneath the cavity 126. In operation of
the illustrative well system 100, the sump 134 functions to collect
fluids and fines received in the cavity 126 to facilitate removal
of the fluids (and sometimes also the fines) to the surface 116.
The inlet 144 of a pump 146 can be provided in the sump 134 to pump
the fluids from the sump 134 to the surface 116. Alternately, the
inlet 144 of the pump 146 can be provided within the cavity 126 or
within the interior of the cavity well 128 to pump fluids from the
cavity 126 to the surface 116. An apertured liner section 152 may
be provided in the cavity 126 and communication with the interior
of the cavity well bore 128. The cavity 126 may be filled with
gravel or other particulate 148 (i.e. gravel packed) to help
support the cavity 126 from collapse and to filter against passage
of pieces of the subterranean zone 114 to the surface 116.
[0037] The secondary well bores 112 are depicted as extending
substantially horizontal within the subterranean zone 114 that
likewise extends substantially horizontal. The secondary well bores
112 need not be horizontal, and in other instances, one or more of
the secondary well bores 112, or portions thereof, may be vertical,
slanted, undulating, or otherwise not horizontal. In one instance,
one or more of the secondary well bores 112 is slanted to follow
the updip or the downdip of the subterranean zone 114. One or more
of the secondary well bores 112 may, alternately or additionally,
have a shallow slope that causes fluids received in the secondary
well bores 112 to flow towards the cavity 126.
[0038] FIG. 2 depicts the secondary well bores 112 originating from
the same location about the end of the second portion 120 of the
surface well bore 110. In other instances, one or more of the
secondary well bores 112 can originate from distinct locations
within or apart from the surface well bore 110 or subterranean zone
114. The secondary well bores 112, or portions thereof, may be
substantially parallel to other of the secondary well bores 112 or
may diverge from other of the secondary well bores 112. In FIG. 2,
the secondary well bores 112 are depicted as diverging from one
another near their origin and being substantially parallel to one
another in a portion that intersects the cavity 126. As is seen in
FIG. 3, the secondary well bores 112 thereafter diverge and extend
to a boundary of a specified access area 142 to more evenly access,
for example to drain, the specified access area 142. All of the
secondary well bores 112 may be substantially aligned in the same
horizontal, vertical or other plane, or one or more of the
secondary well bores 112 may reside at least partially out of plane
with others of the secondary well bores 112.
[0039] It should be appreciated that the systems and methods of
using the illustrative liner system 10 described herein are
described with respect to the specific configuration of the
illustrative well system 100 for convenience of discussion only.
The systems and methods described herein can be applied equally to
other configurations of well systems and well bores. For example,
other well systems may omit the cavity well bore, have different
patterns of secondary well bores, or have other different
configurations.
[0040] One or more of the secondary well bores 112 is provided with
an illustrative liner system 10 that extends through at least a
portion thereof. The liner systems 10 may be provided, for example,
to prevent the subterranean zone 114 from collapsing into the
secondary well bores 112. FIG. 2 depicts a liner system 10 provided
in two of the completed secondary well bores 112, and a liner 138
optionally excluding the whipstock surface 40 installed the last
installed liner system 10. The liner systems 10 and liner 138
extend from about the second portion 120 of the surface well bore
110 and through the cavity 126 continuing on into the subterranean
zone 114. The liner systems 10 and/or liner 138 may further extend
to the end of each of the secondary well bores 112. One or more of
the liners 10, 138 and/or liner tubings 18 may be provided with
apertures 140 to allow passage of fluid between their respective
exterior and interior. The liners 10, 138 and/or liner tubings 18
may, in some instances, be jointed lengths of tubing connected by
collars 150. In other instances, the liners 10, 138 and/or liner
tubings 18 may be continuous tubing. The liners 10, 138 and/or
liner tubings 18 may be affixed or otherwise intended to reside in
the secondary well bores 112 for the life or a majority of the life
of the well system 100.
[0041] Turning now to FIG. 4, an illustrative method for forming
well bores is described with reference to the construction of
illustrative well system 100. In construction of the illustrative
well system 100, the cavity well bore 128 is drilled from the
surface 116 to the desired location of the cavity 126 in or near
the subterranean zone 114. If a sump 134 is to be provided, the
cavity well bore 128 may be drilled to extend below the desired
location of the cavity 126. In some instances, a casing 130 can be
positioned (and optionally cemented in place) in the cavity well
bore 128 above the location of the cavity 126. The cavity 126 is
formed through the cavity well bore 128. In one instance, the
cavity 126 is formed using hydraulic or mechanical under reaming
processes. The cavity 126 may be centered about the cavity well
bore 128. As is seen in FIG. 2, the cavity well bore 128 may be
drilled so that the cavity 126 can be formed offset from a corner
of the access area 142 (whether or not the cavity well bore 128
originates offset from a corner of the access area 142).
[0042] The first portion 118 of the surface well bore 110 is
drilled from about the surface 116 towards the subterranean zone
114. The first portion 118 may be located near a corner of the
access area 142 (see FIG. 2). Directional drilling equipment 178
provided on a drill string 180 is then used to drill the curved
portion 122. In one instance, the directional drilling equipment
178 includes a downhole steerable motor, such as a mud motor
coupled to an adjustable bend or fix bend, bent sub, accelerometer
based inclinometer, and magnetic guidance tools. The directional
drilling equipment 178 is coupled to a drilling bit 176 such that
the downhole steerable motor rotates the drilling bit 176. The bent
sub points the downhole steerable motor and drilling bit 176 in a
direction different from the axis of the preceding portions of the
well bore drilled (i.e. first portion 118) when the drill string
180 is not being rotating. When rotated by the downhole steerable
motor, the drill bit 176 drills in the direction it points.
Therefore, by orienting the drill string 180 to point the bent sub
in the desired direction, the drill bit 176 drills the curved
portion 122 of the surface well bore 110. When the curved portion
122 is complete, the second portion 120 may be drilled
substantially straight (in one instance, substantially horizontal)
by rotating the entire drill string 180 while operating the
downhole steerable motor to rotate the drill bit 176. Rotating the
drill string 180 sweeps the bent sub through 360 degrees and the
drill bit 176 does not drill in a single direction off the well
bore axis, but rather sweeps around with the bent sub and drills in
a net direction that is substantially straight. If the bent sub is
adjustable, the angle of the bent sub can be set to 0 degrees
relative to the axis of the well bore to drill a substantially
straight well bore without rotating the drilling string 180.
Although described herein with respect to a sliding steerable motor
and bent sub, it is within the scope of the concepts described
herein to use rotary steerable tools to directional drill.
[0043] In some instances, upon completion of all or some portion of
the surface well bore 110, a casing 124 can be positioned (and
optionally cemented in place) in the surface well bore 110 or
portions thereof.
[0044] A first of the secondary well bores 112 is drilled extending
from the second portion 120 of the surface well bore 110. In one
instance, as shown in the figures, the first drilled secondary well
bore 112 is drilled substantially straight out from the end of the
second portion 120 of the surface well bore 110, through the cavity
126 and diagonally to a distant corner of the specified access area
142 (FIG. 3). When the first drilled secondary well bore 112 is
complete, a liner system 10 can be positioned in the first drilled
secondary well bore 112 using liner running tool 12 and working
string 26. The whipstock surface 40 is positioned about the desired
origination (i.e. kick off) location of the second secondary well
bore 112 to be drilled. Furthermore, as the liner system 10 is
being positioned in the first drilled secondary well bore 112 or
after the liner system 10 is in position, the liner running tool 12
can be rotated via of the working string 26 to orient the whipstock
surface 40. In FIG. 4, the whipstock surface 40 is oriented to
deflect drilling operations downwardly from the longitudinal axis
of the first drilled secondary well bore 112.
[0045] The second drilled secondary well bore 112 originates (i.e.
kicks off) from the second portion 120 of the surface well bore
110. The second drilled secondary well bore 112 can be termed a
lateral well bore to the second portion 120, because it deviates
laterally from the second portion 120. If drilled with the
directional drilling equipment 178 discussed above, the drill
string 180 is rotated to orient the drill bit 176 in the desired
kick off direction. The drill bit 176 is rotated to begin drilling,
and the drill string 180 is pushed axially further into the second
portion 120. The drill bit 176 and drill string 180 deflect off of
the whipstock surface 40 into the sidewall of the well bore and
begin drilling the second drilled secondary well bore 112.
Thereafter, the orientation of the drill string 180 may be
periodically adjusted and/or the drill string 180 may be rotated as
discussed above to control the desired path of the second drilled
secondary well bore 112. The second drilled secondary well bore 112
is drilled to diverge from (substantially vertically below) the
first drilled secondary well bore 112 for a distance, substantially
track the first drilled secondary well bore 112 for a distance,
intersect the cavity 126, and as is seen in FIG. 3 further diverge
from (substantially horizontally to the side) the first drilled
secondary well bore 112 to an intermediate boundary of the
specified access area 142.
[0046] Turning now to FIG. 5, when the second of the secondary well
bores 112 is complete, the drill string 180 is withdrawn to the
surface 116, and a second liner system 10 is positioned in the
second drilled secondary well bore 112 using the liner running tool
12 and working string 26. The second liner system 10 deflects off
of the whipstock surface 40 of the liner positioned in the first
drilled secondary well bore 112 as it is run into the second
drilled secondary well bore 112. The whipstock surface 40 of the
second liner system 10 is positioned about the desired kickoff
location of the third secondary well bore 112 to be drilled. In
FIG. 5, the liner system 10 extends into the second portion 120 of
the surface well bore 110. As the liner system 10 is being
positioned in the second drilled secondary well bore 112 or after
the liner system 10 is in position, the liner running tool 12 can
be rotated via the working string 26 to orient the whipstock
surface 40. In FIG. 5, the whipstock surface 40 is oriented to
deflect drilling operations downwardly from the longitudinal axis
of the second portion 120 of the surface well bore 110.
[0047] The third drilled secondary well bore 112 kicks off from the
second portion 120 of the surface well bore 110. The third drilled
secondary well bore 112 can be termed a lateral well bore to the
second portion 120, because it deviates laterally from the second
portion 120. The drill bit 176 is rotated to begin drilling and the
drill string 180 is pushed axially into the second portion 120. The
drill bit 176 and drill string 180 deflect off the whipstock
surface 40 into the sidewall of the well bore and begin drilling
the third drilled secondary well bore 112. The third drilled
secondary well bore 112 is drilled to diverge from (substantially
vertically below) the second drilled secondary well bore 112 for a
distance, substantially track the second drilled secondary well
bore 112 for a distance, intersect the cavity 126 and as is seen in
FIG. 3 further diverge from (substantially horizontally to the
side) the second drilled secondary well bore 112 to an intermediate
boundary of the specified access area 142.
[0048] When the third drilled secondary well bore 112 is complete,
a liner 138 may be positioned within the third drilled secondary
well bore 112. The liner 138 may be provided to terminate in or
about the casing 124. In one instance, the liner 138 can be
provided with a packer 144 that substantially seals the annulus
between the liner 138 and the casing 124.
[0049] It should be clear from the discussion above that additional
well bores beyond the three secondary well bores 112 discussed
above, or fewer well bores can be formed.
[0050] Upon completion of the secondary well bores 112, the cavity
126 is gravel packed and the apertured liner section 152 is
installed. The pump inlet 144 can be positioned in the sump 134,
the cavity 126 or the cavity well bore 128, and the pump 146
operated to withdraw fluid and fines to the surface while the
subterranean zone 114 is produced either through the surface well
bore 110 or through the cavity well bore 128. The setting collars
16 (and thus whipstock surfaces 40) of each liner system 10
installed in the secondary well bores 112 remain in the secondary
well bores 112 indefinitely, and at least during production.
Accordingly, fluids from the subterranean zone 14 that enter the
liner tubings 18 may flow through the interior of the setting
collars 16 to the surface if some or all of the fluids of the
subterranean zone 114 are produced through the surface well bore
110.
[0051] A number of embodiments of the invention have been
described. Nevertheless, it will be understood that various
modifications may be made without departing from the spirit and
scope of the invention. Accordingly, other embodiments are within
the scope of the following claims.
* * * * *