Note: Descriptions are shown in the official language in which they were submitted.
TITLE: SHIFTABLE TUBULAR VALVE ASSEMBLY AND PROCESS FOR
DIRECTING FLUID FLOW IN A WELLBORE
FIELD OF THE DISCLOSURE
[0001] The present disclosure relates to wells and in particular valve
assemblies
and processes for directing fluid flow in wells.
BACKGROUND OF THE DISCLOSURE
[0002] The following paragraphs are provided by way of background to the
present disclosure. They are not, however, an admission that anything
discussed
therein is prior art or part of the knowledge of persons skilled in the art.
[0003] Subterranean oil and gas wells require the inflow of hydrocarbon
products
from reservoir rock formations into the well. Various techniques, commonly
known
as completions, have evolved to condition a well in order to enable transport
of
hydrocarbon products from the surrounding rock formation to the wellbore. This
includes a technique, known as multistage completion, involving the isolation
of
multiple zones of a reservoir formation along a wellbore and sequential staged
treatment of each zone with stimulation fluids to promote fracturing of the
rock
formation and flow of hydrocarbons. In order to accomplish this, operators
typically
install a tubular wellbore string, also known as a completion string or liner.
[0004] For example, in multistage completions known as open hole completions,
the completion string commonly contains multiple shiftable sleeve valves
flanked
by packers, as well as a wellbore isolation valve at the distal end of the
string.
Shifting of a sleeve valve results in the opening of a side port in the sleeve
housing,
allowing fluid communication between the central string bore and the wellbore
and
rock formation. One well known technique to achieve this involves deploying a
ball
into the completion string. The ball travels through the completion string
until it
makes contact with a matching ball seat within a sleeve valve of the
completion
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string. The sleeve valve is designed so that upon the ball making contact with
the
ball seat, it actuates shifting of the sleeve valve via hydraulic pressure
provided
from the surface to thereby open the side port in the sleeve housing. At the
same
time, when the ball contacts the ball seat, the ball can seal off the central
string
bore. Thus, fluid flow through the string is directed through the side ports,
thereby
making it is possible to sequentially treat zones from a distal end to a
proximal end
of the well. The sleeve valve systems used in these operations are generally
built
to operate under high hydraulic pressures (e.g., in excess of 2,000 psi) and
to treat
the rock formation at such high pressures to cause fracturing of the rock
formation.
[0005] In certain circumstances, it is desirable to install a valve system
that allows
for fluid treatment of a hydrocarbon bearing rock formation using low
hydraulic
pressures. For example, following initial treatment, for example, by an
initial high
pressure hydraulic fracturing operation, it may be desirable to extract
further
residual hydrocarbon from a rock formation. In such operations, known in the
art
as "enhanced recovery" operations, it can be desirable to fluid treat a rock
formation using low fluid pressures.
SUMMARY OF THE DISCLOSURE
[0006] The following paragraphs are intended to introduce the reader to the
more detailed description that follows and not to define or limit the claimed
subject
matter of the present disclosure.
[0007] In one aspect, the present disclosure relates to wellbore systems.
[0008] In another aspect, the present disclosure relates to tool assemblies
for
directing fluid flow for use in wellbore systems.
[0009] Accordingly, the present disclosure provides, in one broad aspect, in
accordance with the teachings herein, in at least one example embodiment, a
tubular valve assembly for directing and controlling fluid flow in a wellbore,
the
valve assembly comprising:
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a first tubular member having a port through a wall of the first
tubular member, the port being covered by a fluid degradable barrier; and
a second tubular member located exteriorly to the first tubular
member and displaceable relative to the first tubular member from a port-
closed position to a port-open position;
the second tubular member further being arranged so that in a port-
closed position there is no fluid communication from an exterior of the
valve assembly to an inner passage of the first tubular member through
the port, and the second tubular member covers the degradable barrier to
prevent fluid contact between the exterior of the valve assembly and the
degradable barrier; and
the second tubular member being displaceable by application of a
fluid flow in the inner passage of the first tubular member at a hydraulic
pressure that is sufficient to cause the second tubular valve to shift from
the port-closed position to the port-open position, the degradable barrier in
the port-open position being exposed to and contacted by fluid to the
exterior of the valve assembly causing the degradable barrier to gradually
degrade the barrier for a delay period during which the applied fluid flow in
the inner passage can be controlled without regard to an exterior fluid flow
that is to the exterior of the tubular valve assembly, and upon
disintegration of the degradable barrier a fluid communication is
established between the exterior of the valve assembly and the inner
passage.
[0010] In at least one embodiment, the valve assembly can include a hydraulic
actuation member.
[0011] In at least one embodiment, the hydraulic actuation member can include
an actuation aperture forming a second fluid communication between the
interior
of the valve assembly and the second tubular member.
[0012] In at least one embodiment, the valve assembly further can include a
plug
or a surface coating that is disposed between the degradable barrier and the
inner
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passage of the first tubular member to protect the degradable barrier from
degradation due to fluids in the inner passage of the first tubular member.
[0013] In at least one embodiment, the plug can be a cylindrical plug radially
disposed between the inner passage of the first tubular member and the
degradable barrier, and upon disintegration of the degradable barrier the plug
member is radially exteriorly displaceable by the fluid flow through the inner
passage of the first tubular member.
[0014] In at least one embodiment, the port can be an inwardly radially
narrowing port.
[0015] In at least one embodiment, the valve assembly can include a shear pin
that is arranged to couple the first tubular member to the second tubular
member
and during the application of the fluid flow in the inner passage of the first
tubular
member the shear pin is arranged to shear thereby allowing displacement of the
second tubular member.
[0016] In at least one embodiment, the delay period can be sufficiently long
to
hydraulically shift at least one other hydraulically controllable component
installed
on a tubular string together with the valve assembly from a first operable
position
to a second operable position.
[0017] In at least one embodiment, the delay period can be from about 48 hours
to about 1 hour.
[0018] In at least one embodiment, fluid communication between the exterior of
the valve assembly and the inner passage can be established by a second fluid
flow at a hydraulic pressure that is sufficient to form a fluid-front in a
hydrocarbon
bearing rock formation surrounding the valve assembly installed in the
wellbore.
[0019] In at least one embodiment, the hydraulic pressure can be from about
100 psi to about 1,000 psi.
[0020] In at least one embodiment, the hydraulic pressure that is sufficient
to
displace the second tubular member can be larger than the hydraulic pressure
that
is sufficient to form a fluid-front in a hydrocarbon bearing rock formation.
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[0021] In another aspect, the present disclosure relates to processes for
controlling fluid flow in a subterranean well. Accordingly, the present
disclosure
further provides, in one broad aspect, in at least one example embodiment, a
process for controlling fluid flow in a wellbore string, the process
comprising:
installing a wellbore string in a wellbore, the wellbore string having
a central bore therethrough and comprising a side-ported two member
tubular valve assembly interconnecting two successive portions of the
string, the tubular valve assembly being shiftable from a port-closed
position to a port-open position, and having a fluid degradable barrier
covering the port, the degradable barrier being covered by one of the
tubular valve members in the port-closed position to prevent fluid contact
between an exterior of the tubular valve and the degradable barrier; and
applying fluid flows to the central bore at sufficient hydraulic
pressures to:
cause the tubular valve assembly to shift from the port-
closed position to the port-open position;
expose the degradable barrier to the exterior of the tubular
valve assembly to permit fluid contact between the barrier and fluid
to the exterior of the tubular valve assembly;
degrade the barrier during a delay period until the
degradable barrier is disintegrated; and
establish fluid communication between the central bore and
the exterior of the tubular valve assembly when the barrier is
disintegrated.
[0022] In at least one embodiment, the process can further include applying a
first fluid flow at a first hydraulic pressure sufficient to cause the tubular
valve
assembly to shift from the port-closed position to the port-open position, and
then
applying a second fluid flow at a second hydraulic pressure to establish fluid
communication between the central bore and the exterior of the tubular valve
assembly.
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[0023] In at least one embodiment, the second fluid flow at the second
hydraulic
pressure can further be sufficient to form a fluid-front in a hydrocarbon-
bearing
rock formation surrounding the valve assembly to displace hydrocarbons from
the
rock formation into the wellbore.
[0024] In at least one embodiment, the first hydraulic pressure can be higher
than
the second hydraulic pressure.
[0025] In at least one embodiment, the first hydraulic pressure can be a
pressure
of from about 1,000 psi to about 4,000 psi and the second hydraulic pressure
can
be a pressure of from about 100 psi to about 1,000 psi.
[0026] In at least one embodiment, the process can further include, during the
delay period, hydraulically shifting at least one other hydraulically
controllable
component installed on the tubular string together with the valve assembly
from a
first operable position to a second operable position.
[0027] In at least one embodiment, the wellbore string can comprise two or
more
of the side-ported valve assemblies separated from one another by a portion of
the
wellbore string, and the process further includes applying fluid flow at a
sufficient
pressure to the central bore to cause each of the two or more side-ported
valve
assemblies to simultaneously or sequentially shift from the port-closed
position to
the port-open position.
[0028] In at least one embodiment, the process further includes applying fluid
flow at a sufficient pressure to the central bore to cause each of the two or
more
side-ported valve assemblies to:
(i) shift from the port-closed to the port-open position;
(ii) expose the degradable barrier in each of the valve assemblies to the
exterior of the valve assemblies to permit fluid contact between the barriers
and fluid to the exterior of the valve assemblies;
(iii) degrade the barrier during a delay period until the degradable
barrier is disintegrated; and
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(iv) establish fluid communication between the central bore and the
exterior of the tubular valve assemblies when the barriers are
disintegrated; and
wherein the performance of all of steps (i) to (iv) is completed for a first
of the two
side-ported valves before the performance of these steps is initiated in
respect of
a second of the two or more side-ported valves.
[0029] In at least one embodiment, the wellbore string can be installed inside
another larger diameter wellbore string.
[0030] In at least one embodiment, the larger diameter wellbore string can
include an additional side-ported valve, and the process further includes upon
establishing fluid communication between the central bore and an exterior of
the
tubular valve assembly, establishing fluid communication between the tubular
valve assembly and the wellbore by actuating the side ports of the additional
side-
ported valve.
[0031] In at least one embodiment, the larger diameter wellbore string can
include two or more other side-ported valves, and the process further includes
upon establishing fluid communication between the central bore and an exterior
of
the tubular valve assembly, establishing fluid communication between the
tubular
valve assembly and the wellbore by actuating the side ports of the two or more
other side-ported valves.
[0032] In another aspect, the present disclosure relates to use of the valve
assembly of the present disclosure. Accordingly, the present disclosure
further
provides, in one broad aspect, in at least one example embodiment, a use of a
tubular valve assembly to establish a contiguous fluid front in a hydrocarbon
bearing rock formation to thereby displace the hydrocarbon from the rock
formation
into a wellbore, the assembly comprising:
a first tubular member having a port through a wall of the tubular
member, the port covered by a fluid degradable barrier;
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a second tubular member located exteriorly to the first tubular
member and being displaceable relative to the first tubular member from a
port-closed position to a port-open position;
the second tubular member further being arranged so that in the
port-closed position there is no fluid communication from an exterior of the
valve assembly to an inner passage of the first tubular member through
the port, and the second tubular member covers the degradable barrier to
prevent fluid contact between the exterior of the valve assembly and the
degradable barrier; and
the second tubular member being displaceable by application of a
fluid flow in the inner passage at a hydraulic pressure that is sufficient to
cause the tubular valve to shift from the port-closed position to the port-
open position, the degradable barrier in the port-open position being
exposed to and contacted by fluid to the exterior of the valve assembly
causing the degradable barrier to gradually degrade for a delay period
during which the applied fluid flow in the inner passage can be controlled
without regard to the fluid flow to the exterior of the tubular valve system,
and upon disintegration of the degradable barrier a fluid communication is
established between the exterior of the valve assembly and the inner
passage.
[0033] Other features and advantages of the present disclosure will become
apparent from the following detailed description. It should be understood,
however,
that the detailed description, while indicating preferred embodiments of the
present
disclosure, are given by way of illustration only, since various changes and
modifications within the spirit and scope of the disclosure will become
apparent to
those skilled in the art from the detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] The disclosure is in the hereinafter provided paragraphs described in
relation to its figures. The figures provided herein are for illustration
purposes and
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are not intended to limit the present disclosure. Like numerals designate like
or
similar features throughout the several views possibly shown situated
differently or
from a different angle. Thus, by way of example only, part 215 in FIG. 2 and
FIG.
3A refers to a tubular string in both of these figures.
[0035] FIG. 1 is a schematic view of an example configuration of a well
arrangement.
[0036] FIG. 2 is schematic view of an example configuration of a portion of a
well
arrangement having a wellbore string with shiftable tubular valve assemblies
in
accordance with the teachings herein.
[0037] FIG. 3A is an elevated side view of a shiftable valve in a first state.
[0038] FIG. 3B is a cross-sectional view of a shiftable valve attached to a
wellbore string and installed in a wellbore section, shown in the same state
as in
FIG. 3A.
[0039] FIG. 3C is an enlarged cross-sectional view of the area marked 3C in
FIG.
3B.
[0040] FIG. 4A is an elevated side view of a shiftable valve in a second
state.
[0041] FIG. 4B is a cross-sectional view of a shiftable valve attached to a
wellbore string and installed in a wellbore section, shown in the same state
as in
FIG. 4A.
[0042] FIG. 4C is an enlarged cross-sectional view of the area marked 4C in
FIG.
4B.
[0043] FIG. 5A is an elevated side view of a shiftable valve in the second
state
after the degradable barrier has disintegrated.
[0044] FIG. 5B is a cross-sectional view of a shiftable valve attached to a
.. wellbore string and installed in a wellbore section, shown in the same
state as in
FIG. 5A.
[0045] FIG. 5C is an enlarged cross-sectional view of the area marked 5C in
FIG.
5B.
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[0046] FIG. 6 is a schematic view of an example configuration of a portion of
a
well arrangement.
[0047] FIGS. 7A, 7B, 7C, and 7D are schematic overviews of example
configurations of portions of a well arrangement.
[0048] The figures together with the following detailed description make
apparent
to those skilled in the art how the disclosure may be implemented in practice.
DETAILED DESCRIPTION OF THE DISCLOSURE
[0049] Various apparatuses and processes will be described below to provide an
example of an embodiment of each claimed subject matter. No embodiment
described below limits any claimed subject matter, and any claimed subject
matter
may cover any apparatuses, assemblies, methods, processes, or systems that
differ from those described below. The claimed subject matter is not limited
to any
apparatuses, assemblies, methods, processes, or systems having all of the
features of any apparatuses, assemblies, methods, processes, or systems
described below or to features common to multiple or all of the any
apparatuses,
assemblies, methods, processes, or systems below. It is possible that an
apparatus, assembly, method, process, or system described below is not an
embodiment of any claimed subject matter. Any subject matter disclosed in an
apparatus, assembly, method, process, or system described below that is not
claimed in this document may be the subject matter of another protective
instrument, for example, a continuing patent application, and the applicants,
inventors, or owners do not intend to abandon, disclaim, or dedicate to the
public
any such subject matter by its disclosure in this document.
[0050] All publications, patents, and patent applications referenced herein
are
herein incorporated by reference in their entirety to the same extent as if
each
individual publication, patent, or patent application was specifically and
individually
indicated to be incorporated by reference in its entirety.
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[0051] Several directional terms such as "above", "below", "lower", "upper",
"inner", and "outer" are used herein for convenience, including for reference
to the
drawings. In general, the terms "upper", "above", "upward", "uphole",
"proximal",
and similar terms are used to refer to a direction towards the earth's surface
along
the wellbore, while the terms "lower", "below", "downward", "downhole", and
"distal"
are used to refer to a direction generally away from the earth's surface along
the
wellbore. The terms "inner" and "inward" are used herein to refer to a
direction that
is more radially towards the central longitudinal axis of a tubular component,
while
the terms "outer" and "outward" refer to a direction that is more radially
away from
the central longitudinal axis of a tubular component.
[0052] As used herein, the wording "and/or" is intended to represent an
inclusive-
or. That is, "X and/or Y" is intended to mean X or Y or both, for example. As
a
further example, "X, Y, and/or Z" is intended to mean X or Y or Z or any
combination thereof.
[0053] It will be understood that any range of values described herein is
intended
to specifically include any intermediate value or sub-range within the given
range,
and all such intermediate values and sub-ranges are individually and
specifically
disclosed (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.90, 4, and 5). It is
also to be
understood that all numbers and fractions thereof that are modified by the
term
"about" are presumed to include a variation of up to a certain amount of the
number
to which reference is being made if the end result is not significantly
changed, such
as 1%, 2%, 5%, or 10%, for example.
[0054] It will also be understood that the word "a" or "an" is intended to
mean
"one or more" or "at least one", and any singular form is intended to include
plurals
herein, unless expressly specified otherwise.
[0055] It will be further understood that the term "comprise", including any
variation thereof, is intended to be open-ended and means "included, but not
limited to", unless otherwise specifically indicated to the contrary.
[0056] In general, the valve assembly of the present disclosure can be used to
operate a well in a reservoir of hydrocarbons. Notably, the assembly of the
present
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disclosure permits control of the flow path of fluids in a well. In
particular, the valve
assembly can be used to establish fluid communication between defined sections
within a wellbore and portions of a hydrocarbon reservoir formation
surrounding
these sections.
[0057] In broad terms, the valve assembly of the present disclosure can be
inserted in a wellbore string and shifted from a port-closed position to a
port-open
position to establish fluid communication between the inner passage of the
valve
and the exterior thereof, including the wellbore and surrounding rock
formation.
One disadvantage of known valve systems is that high pressures can be required
to hydraulically shift the valve to an open position. Upon shifting these
known valve
systems, the surrounding rock formation becomes exposed to high pressure
differentials, for example 2,000 psi or more. This can be desirable in
fracturing
operations. However, such high-pressure differentials are problematic in
enhanced
recovery operations since the rock formation can be damaged, and perhaps more
importantly, these pressure differentials can prevent or interfere with the
establishment of a slowly migrating fluid front in the rock formation. The
establishment of such a fluid front is required in an enhanced recovery
operation
to gradually displace hydrocarbon with fluid to thereby effect migration of
residual
hydrocarbon from the rock formation into the wellbore. In these operations, it
is
desirable to inject fluid at low pressures.
[0058] Furthermore, abrupt hydraulic pressure changes in the inner passage of
the wellbore string can pose challenges for operators who wish to
hydraulically
control other components of the wellbore string, for example other valves or
packers, upon having opened up the valve. This typically then requires
operators
to deploy mechanical tools, for example various shifting or setting tools,
coupled
to coiled tubing or a wire line from the surface to control these components,
which
can be a time consuming and expensive process.
[0059] By contrast, the valve assembly of the present disclosure can be
operated
so that only modest hydraulic pressure differentials between the inner
wellbore
string and the rock formation are established, for example 500 psi, or less.
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However, the pressure applied for shifting the valve can be well in excess
thereof.
This renders the valve assembly of the present disclosure particularly
suitable for
the extraction of residual hydrocarbon from a rock formation by flooding of
the rock
formation, i.e., gradual hydrocarbon displacement by fluids injected at low
pressure, for example, following a high pressure fracturing operation. It is
noted
that in this regard, reference is made in the present disclosure to the phrase
"a
fluid flow having a hydraulic pressure sufficient to form a fluid-front", by
which it is
meant a fluid flow having a hydraulic pressure that is sufficient to form a
more or
less contiguous gradually migrating fluid front within a hydrocarbon bearing
rock
formation, for example, within a portion of a rock formation surrounding a
valve, to
displace hydrocarbons within the rock formation.
[0060] Furthermore, the valve assembly of the present disclosure can be
hydraulically shifted without pressure changes in the inner passage for a
period of
time. During this time period, other components in the wellbore string may be
controlled hydraulically, obviating the need for mechanical intervention.
[0061] Example embodiments are hereinafter described with reference to the
drawings.
[0062] Referring to FIG. 1, shown therein is an example well arrangement 100
for fracturing an oil or gas reservoir formation 105. A rig 110 is set up at
surface
120 for operating well 130. Rig 110 can initially be a drilling rig and can
later be
representative of well operation equipment, such as fracturing, cementing,
stimulation fluid treatment, or acidizing equipment at selected times. For
simplicity,
any type of surface rig or tool deployment rig, including a mobile rig, such
as a
truck, can be represented by rig 110.
[0063] Well 130 comprises a vertical well section 140 and a horizontal well
section 150. In operation, rig 110 can be used to apply fluids, for example,
stimulation fluids, through the vertical section 140 of the well 130 to the
reservoir
formation 105 surrounding the horizontal section 150 of the well 130. The
valve
assemblies of the present disclosure can be deployed from rig 110, and permit
control over the application location where fluid is applied in the well 130,
including
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in the horizontal section 150 of well 130 and selected portions of reservoir
formation 105.
[0064] Referring now to FIG. 2, shown therein in further detail (relative to
FIG. 1),
is a portion of an example well arrangement 200 for fracturing an oil or gas
reservoir formation, known as an open hole wellbore system. The shown portion
of the wellbore system 200 comprises a wellbore 202 defined by a wellbore wall
204 drilled into the reservoir formation 205 and having a proximal end p
extending
to the surface (not shown), and a distal end d extending to the end (not
shown) of
the wellbore 202. A tubular string 215 having an inner bore 216 inserted in
the
wellbore 202 forms an axially extending annulus 210 between the wellbore wall
204 and the tubular string 215. The tubular string 215 includes a plurality of
spaced
apart shiftable tubular valve assemblies 220a, and 220b (of which the exterior
view
is shown in FIG. 2), which will be described hereinafter in further detail.
Each valve
assembly 220a and 220b comprises several side ports (not visible) which can be
exposed to allow fluid communication between the tubular string 215 and the
reservoir formation 205 via the annulus 210. A source to provide fluid and
control
fluid circulation can be set up at proximal end p of the well 130 so that
fluid flows
within the tubular string 215, as indicated by arrow F towards distal end d of
the
tubular string 215, whence fluid can flow into the annulus 210. Although two
shiftable tubular valve assemblies 220a, and 220b are shown, more or fewer
tubular valve assemblies may be used in practice. Thus, in some embodiments,
10, 20, 30, 40, 50, or more tubular valve assemblies may be used.
[0065] To provide zonal isolation, tubular isolating elements 230, 232, 234
are
placed at the proximal and distal ends of each valve assembly 220a and 220b,
so
as to create fluid flow barriers between each valve assembly 220a and 220b and
the surface. The tubular isolating elements 230, 232 and 234 can be packers,
cup
seals, or other isolation devices. Once the tubular string 215 is run into the
wellbore
202 and placed in the desired position, the tubular isolating elements 230,
232,
and 234 can be set to provide a substantially fluid tight seal between the
wellbore
wall 204 and the exterior of the tubular string 215, as will be understood by
those
of skill in the art. Once the valve assembly 220a or 220b is opened and fluid
is
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permitted to flow from the inner bore 216 to the annulus 210, the fluid and
pressure
is contained to the area between the isolating elements, for example, between
tubular isolating elements 230 and 232, or between tubular isolating elements
232
and 234. Fluid treatment can then be concentrated on portions of the rock
formation 205 between these pairs of isolating elements. By this method,
different
portions of the formation 205 can be subjected to a desired treatment regimen,
for
example, certain types and/or amounts of fluids and certain pressures that
need
not be the same for each valve assembly. Thus, for example, the portion 205a
of
the rock formation 205 between tubular isolating elements 230 and 232 may be
treated differently than the portion 205b between tubular isolating elements
232
and 234. The spacing, number, and placement of the tubular isolating elements
230, 232, and 234, and valves 220a and 220b can vary and can be determined by
one skilled in the art, for example, a completions engineer familiar with the
described open hole wellbore systems.
[0066] In at least one embodiment, the wellbore 202 has an outer diameter of
4.5
inches and an inner diameter of 4 inches, such that the wellbore wall 204 has
a
thickness of 0.25 inches. The tubular string 215 has an outer diameter of 3
inches
and an inner diameter of 2 inches, such that the wall of the tubular string
215 has
a thickness of 0.5 inches. Accordingly, the inner bore 216 has a diameter of 2
inches. The annulus 210 formed therefrom has an wellbore inner diameter of 4
inches and a tubular string outer diameter of 3 inches. The valve assemblies
220a
and 220b have an outer diameter of slightly less than 4 inches at their widest
parts
such that the outer portions of the valve assemblies 220a and 220b are located
adjacent to the inner portion of the wellbore wall 204. The tubular isolating
elements 230, 232, and 234 when installed have an outer diameter of 4 inches
such that at their widest parts the outer portions of the tubular isolating
elements
230, 232, and 234 are in contact with the wellbore wall 204. It will be
appreciated
that this embodiment has been provided for illustration purposes only, and
that
other dimensions and proportions may be more suitable in different
circumstances.
[0067] In some embodiments, inner bore 216 of the valve assemblies has a
diameter of from about 1 inch to about 4 inches, and the length between
proximal
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end p1 and distal end dl of the valve assemblies is from about 10 inches to
about
20 inches.
[0068] In another example well implementation (not shown), the wellbore system
can be a cemented wellbore system. In such a system, cement is used to form a
lining for the wellbore prior to fluid treatment of the rock formation.
[0069] In further well implementations (not shown), the wellbore or certain
sections thereof, can be lined with casing, in which an annulus is formed
between
the wellbore string and the casing.
[0070] It is noted that in the well assembly 200, in addition to including the
shiftable valve assemblies 220a and 220b, which typically serve to
interconnect
two pieces of tubing, the tubular string 215 of the wellbore system further
can
include additional tools, including, without limitation, additional isolating
elements
capable of sealing the annulus 210 between the tubular string 215 and the
wellbore
wall 204, and other valves. As will be appreciated by those skilled in the
art, such
additional isolating elements and other valve assemblies can also be spaced in
various ways relative to one another to achieve a desired interval length or
number
of ports per interval. In addition, well assemblies can include several other
operational devices, including, for example, cementing tools (not shown),
and/or a
wellbore isolation valve (not shown), as is known by those skilled in the art.
As
further will be appreciated by those of skill in the art, these tools may be
operable
from the surface.
[0071] In general, the valve assemblies 220a and 220b are deployed as part of
the tubular string 215 to control fluid flow therethrough. In particular, the
valve
assemblies 220a and 220b can be deployed to control the opening of ported
intervals through the tubular string 215 and are each operable from a port-
closed
position to a port-open position wherein fluid flow is permitted through the
ports
either from or to the surrounding reservoir formation 205. In general, the
valve
assemblies 220a and 220b can be actuated, causing one or more of the valve
assemblies 220a and 220b to shift from a port-closed position to a port-open
position. Conveniently, the valves assemblies 220a and 220b of the present
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disclosure can be hydraulically actuated through a hydraulic actuation member.
In
an example embodiment, the hydraulic actuation member can include a vent 222a
and 222b, which will hereinafter be described in further detail. In some
embodiments, a single actuation can open a plurality of valves in a wellbore
string.
In other embodiments, a first actuation can open a first valve in a wellbore
string,
and a second actuation can open a second valve in a wellbore string. Valve
assemblies 220a and 220b are constructed in such a manner that upon shifting,
fluid cannot immediately flow from the inner bore 216 of the tubular string
215
through the ports into the annulus 210. Instead, for a certain period of time,
herein
termed a "delay period", the fluid flow within the inner bore 216 of the
tubular string
215 remains controllable without regard for the fluid flow in the annulus 210
or the
reservoir formation 205. Upon expiration of the delay period, fluid can flow
through
the port to the annulus 210 and contact reservoir formation 205. Furthermore,
conversely, upon expiration of the delay period, fluid can flow from the
reservoir
formation 205 to the annulus 210 into the inner bore 216 of the tubular string
215.
[0072] The tubular string 215, including the valve assemblies 220a and 220b,
and optionally other operational devices, can be run in and installed in the
wellbore
202 typically with each of the valve assemblies 220a and 220b, in a port-
closed
position. The valve assemblies 220a and 220b can be shifted into their port-
open
position when the tubular string 215 is ready for use and ready for fluid flow
to or
from the reservoir formation 205.
[0073] It should be clearly understood that the valve assembly and methods of
the present disclosure are not limited in any way to use in conjunction with
the
example well arrangements 100 and 200 shown in FIG. 1 and FIG. 2,
respectively.
On the contrary, a wide variety of wellbore arrangements and configurations
having a requirement for directing fluid in a wellbore can be constructed, and
at
least one tool assembly of the present disclosure and at least one process of
the
present disclosure can be used in conjunction with these wellbore arrangements
and configurations.
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[0074] According to one example embodiment of the present disclosure, well
arrangements, such as the well arrangements 100 and 200, can, in one
embodiment, be operated as illustrated in FIGS. 3A-3C, 4A-4C, and 5A-5C. In
general overview, in FIGS. 3A-3C, a valve assembly 220a is shown in an initial
port-closed position. In FIGS. 4A-4C, the valve assembly 220a is shown in a
port-
open position with a degradable barrier 360 in place. In FIGS. 5A-5C, the
valve
assembly 220a is shown in a port-open position following disintegration of the
degradable barrier 360. It is noted that side views of the valve assembly 220a
are
shown in FIGS. 3A, 4A, and 5A, while cross sections of the valve assembly 220a
are shown in FIGS. 3B, 3C, 4B, 4C, 5B, and 5C.
[0075] As shown in FIGS. 3A-3B, initially a tubular string 215 having an inner
bore 216 comprising a valve assembly 220a in a port-closed position can be run
into a wellbore 202 within a reservoir formation 205 and installed, to
achieve, for
example, a well arrangement as depicted in FIG. 2. The downhole depth may be
selected as desired. In at least one embodiment, the downhole depth location
of
the valve assembly 220a within the wellbore 202, relative to the surface, can
generally be established by measuring the length of the section of wellbore
liner
between a valve assembly or other known equipment and the surface, or other
known methodologies may be used.
[0076] The axially extending valve assembly 220a has a distal end dl and a
proximal end p1. Valve assembly 220a is constructed to have a first tubular
member 305 and a second tubular member 310 collectively forming an inner valve
bore 302 axially extending from and to the inner bore 216 of the tubular
string 215.
The first tubular member 305 has threads 340 on an inner surface of its
proximal
end portion. The first tubular member 305 is proximally coupled to the tubular
string
portion 215a via the threads 340. Likewise, the first tubular member 305 has
threads 341, on an inner surface of its distal end portion. Distally first
tubular
member 305 is coupled to a tubular extension member 375, 375b via the threads
341 and further secured via set screws 342 and 343 which can be accessed for
assembly and disassembly purposes from the exterior of the valve assembly 220a
via apertures 346 and 347. In turn, tubular extension member 375, 375b is
distally
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coupled to the tubular string portion 215b. It is noted that the distal
portion 375b of
tubular member 375 is not shown as a cross section, but rather as a side view,
hence the coupling thread is not shown.
[0077] The second tubular member 310 is coupled to the first tubular member
305 via shear pins 315 and 316. Furthermore, a support member 395, which is
exterior of and coupled to the first tubular member 305 via threads 343 and
set
screws 368 and 369, separates a portion of the first tubular member 305 and
the
second tubular member 310, and furthermore the support member 395 provides
support to the second tubular member 310. Various seal members, such as 0
rings
330, 331, 332, 333, and 334, ensure that in the closed position of the valve
assembly 220a shown in FIGS. 3A-3B, there is no fluid contact between the
inner
valve bore 302 and the exterior wellbore 202.
[0078] The valve assembly 220a further includes an interior actuation aperture
355 through an inner surface of the first tubular member 305, shown in detail
in
FIG. 3C, which represents a fluid communication between the inner valve bore
302
and compartment 365. It is noted that a single actuation aperture 355 is
shown;
however, in other embodiments, 2, 3, 4, 5, or more actuation apertures may be
included. Further apertures included are vent apertures 385 and 386 through
the
second tubular member 310, which represent fluid communication between the
exterior of the valve assembly 220a (i.e., the annulus 210) and vent
compartment
387 that is formed between an outer surface of the first tubular member 305
and
an inner surface of the second tubular member 310.
[0079] In addition to being separated by the support member 395, the first
tubular
member 305 and second tubular member 310 are also separated by a degradable
barrier 360, which is disposed between the first tubular member 305 and the
second tubular member 310 at a proximal portion of the second tubular member
310 and covers port apertures 398 and 399. In the shown embodiment, the
degradable barrier 360 is annularly shaped and radially exteriorly disposed
relative
to the first tubular member 305. In other embodiments, the degradable barrier
360
can have different geometrical shapes, or it can be constructed out of
separate
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degradable barrier elements. For example, in embodiments where multiple ports
are included, each port can be covered by a separate degradable barrier
element.
In the closed position shown in FIGS. 3A-3B, the degradable barrier 360 is not
in
fluid contact either from the exterior or from the interior. In the shown
embodiment,
plugs 381 and 382 (further shown in FIG. 4C and described hereinafter) are
located in channels in the first tubular member 310 and are radially disposed
between the inner bore 302 and the degradable barrier 360 to prevent fluid
contact
from the interior, and portions of the second tubular member 310 cover the
degradable barrier 360 to prevent fluid contact from the outside of the valve
assembly 220a. Interior fluid contact in other embodiments may be prevented
using, for example, a surface coating or a wax seal.
[0080] Side ports in the tubular valve assemblies of the present disclosure
can
be implemented in various ways. In general, side ports are apertures in the
wall of
the tubular valve assembly that allow for fluid communication between the
central
inner passage of the tubular valve assembly and the exterior of the tubular
valve
assembly. In different embodiments, the number of ports can vary. For example,
in different embodiments, the shiftable valve 220a can have 1, 2, 3, 4, 5, 6,
7, 8, 9,
10, or more side ports. Furthermore, the geometry of the ports can vary. Ports
can,
for example, have an oval shape, or in other embodiments, have a round shape
(see e.g.: 505 in FIG. 5A). Radially extending port apertures can also be
shaped
in different geometries. In some embodiments, the port apertures are
cylindrically
or octahedrally shaped. In other embodiments, the ports can have walls that
radially narrow gradually or incrementally (in one or more increments). By way
of
example, referring to the enlarged cross sections FIG. 4C (the degradable
barrier
covered) and FIG. 5C (the ports are open as the degradable barrier has
disintegrated), in one embodiment, port aperture 398 contains a single
incrementally inwardly radially narrowing portion 446 with a wider exterior
portion
and a narrower interior portion. Different port aperture designs can be used
to
achieve different fluid flows through the ports. Thus, for example, an
inwardly
radially narrowing port design such as that shown in FIG. 4C and FIG. 5C will
result
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in a reduced fluid flow through the port aperture 398 relative to a port
without
narrowing portion 446.
[0081] The degradable barrier 360 can be fabricated from any degradable
materials, including for example polyvinyl alcohol-based materials,
polyglycolic
acid-based materials, polylactide polymer-based materials, or alloyed
materials,
such as magnesium or aluminum-based materials, or combinations of any of the
foregoing. Materials can further be selected to react at relatively low
wellbore
temperatures, for example as low as 50 C, and materials can be selected so
that
they react with fresh water exhibiting low chloride concentrations. In this
respect,
materials consisting primarily of magnesium and aluminum are deemed
particularly suitable. In more general terms, degradable materials can be any
materials that can chemically react with one or more fluids that can be
present in
a wellbore, including for example water, a stimulation fluid, a proppant
slurry, an
acid, or a base, in a manner that results in degradation and subsequent
disintegration of the material in a relatively brief time period, for example,
a delay
period of less than about 1 month, or less than about 1 week. In some
embodiments, degradation can be even faster, for example, a delay period of
less
than about 72 hours, less than about 48 hours, less than about 36 hours, less
than
about 24 hours, less than about 12 hours, less than about 6 hours, less than
about
3 hours, less than about 1 hour, less than about 30 minutes, or from about 1
hour
to about 48 hours.
[0082] The delay period provides for at least two operational advantages.
First,
the pressure initially used to open the valve can, during the delay period, be
reduced by reducing the fluid flow from the surface. At reduced pressures, it
is
possible to inject fluid into the rock formation surrounding the valve
assembly and
form a fluid front to displace hydrocarbons and capture these in the well. It
should
be noted that such a fluid injection operation is different from a fracking
operation,
in that the rock formation at these pressures is not fractured, but rather
fluid within
the rock formation is displaced. Second, during the delay period, other
hydraulically controllable tools present in the string can continue to be
controlled.
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[0083] In the closed position shown in FIGS. 3A-3B, the valve assembly 220a
can be installed in the wellbore 202 in a manner in which there is no fluid
communication between the inner bore 302 of the valve assembly 220a or the
inner bore 216 of the tubular string 215, on the one hand, and the annulus 210
or
surrounding rock formation 205, on the other hand. Therefore, the degradable
barrier 360 in this closed position is not subject to degradation.
[0084] Turning now to FIG. 3C, in conjunction with FIG. 3A and FIG. 3B, in
order
to shift the valve assembly 220a from a port-closed position to a port-open
position,
a fluid flow can be established from the surface through the inner bore 216 of
the
tubular string 215 and the inner bore 302 of the valve assembly 220a. The
fluid
flow can exert fluid pressure (PR) via actuation aperture 355 on to the second
tubular member 310. Upon the exertion of sufficient fluid pressure, shear pins
315
and 316 are sheared, and the second tubular member 310 can move in a distal
direction relative to the first tubular member 305. It is noted that fluid
present in
vent compartment 387 in the movement of the second tubular member 310 is
displaced and can escape via the vent apertures 385 and 386. It is further
noted
that the fluid flow may be selected to have hydraulic pressures as desired,
provided
the hydraulic pressure is sufficient to shear the shear pins 315 and 316, and
subsequently shift the second tubular member 310 in the distal axial direction
relative to the first tubular member 305. In some embodiments, the fluid flow
can
be selected to have a hydraulic pressure substantially in excess of the
hydraulic
pressure used to subsequently treat the rock formation surrounding the valve,
as
hereinafter further described. Thus, in some embodiments, hydraulic pressures
used to shift the valve assembly 220a can be about 1,000 psi or more, about
1,500
psi or more, about 2,000 psi, about 3,000 psi or more, or about 4,000 psi or
more,
or from about 1,000 psi to about 4,000 psi, or, for example, from about 1,000
psi
to about 3,000 psi.
[0085] As noted in general, hydraulic pressures can be selected to be
sufficient
to shear shear pins 315 and 316. Shear pins 315 and 316 in turn can be
selected
to be shearable within the pressure ranges set forth herein. Pressure gauges,
generally known to those in the art, can be installed at surface 120, and
pressure
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can be applied using a fluid pump, for example deployed by a pump truck, at
surface using techniques generally known to those in the art. The applied
pressures can be monitored and adjusted until a desired pressure is achieved,
based on the pressure gauge readings.
[0086] Turning now to FIGS. 4A-4B, shown therein is the valve assembly 220a
in a port-open position shortly following actuation and axial displacement of
the
second tubular member 310 in the distal direction. It is noted that the
displacement
of the second tubular member 310 is stopped by displacement limiting surface
362
that is located on an exterior surface of the tubular member 375.
[0087] Advantageously, displacement of the second tubular member 310 results
in the exposure of degradable barrier 360 to the exterior of valve assembly
220a.
Thus, now contact is made between the fluid present in the annulus 210 and the
degradable barrier 360, and thus degradation of the degradable barrier 360 is
initiated. However, no fluid contact is made between the interior bore 302 of
the
valve assembly 220a and the exterior since the degradable barrier 360 covering
port apertures 398 and 399, and the plugs 381 and 382, positioned radially
interiorly relative to the barrier 360, prevent such contact. The port
apertures 398
and 399 are located opposite one another on the first tubular member 305 near
the proximal end portion of the first tubular member 305. In different
embodiments,
the plugs may have different shapes; however, they are shaped so as to
sufficiently
closely fit within the port aperture to prevent fluid contact between the
interior bore
and the degradable barrier. Thus, for example, cylindrical plugs may be used
in
conjunction with cylindrically shaped port apertures, as shown in FIGS. 4C and
5C,
and octahedrally shaped plugs may be used in conjunction with octahedrally
shaped port apertures.
[0088] It is further noted that during displacement of the second tubular
member
310, compartment 365 volumetrically expands as a first surface of the flange
portion of the tubular member 310 adjacent the compartment 365 moves away
from the compartment 365 as the second tubular member 310 moves distally. At
the same time, the volume of vent compartment 387 reduces until it is no
longer
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substantially existent in the closed-port position shown in FIGS. 4A-4B (which
is
why the vent compartment 387 label does not appear in FIG. 4B). This is due to
a
second surface of the flange portion of the tubular member 310 adjacent the
compartment 387 moving toward the compartment 387 as the second tubular
member 310 moves distally. The first and second surfaces of the flange of the
second tubular member 310 are opposite one another. Any fluid present in vent
compartment 387 can escape to the exterior via vent apertures 385 and 386. In
the shown embodiment, in a port-open position, set screws 342 and 343 are
aligned with vent apertures 385 and 386, thus allowing access thereto from the
exterior of the valve assembly 220a. Furthermore, as noted, shear pins 315 and
316 are sheared in the displacement of the second tubular member 310 leaving
sheared shear pins 405 and 406, respectively.
[0089] As noted, upon exposure following displacement of the second tubular
member 310 to a port-open position, degradation of the degradable barrier 360
is
initiated. Such degradation starts from the outside in, and for a period of
time (i.e.,
the delay period), the barrier 360 remains intact and there is no fluid
communication between the annulus 210 and the inner valve bore 302, or vice-
versa. Thus, during the delay period, fluid flow inside the inner bore 302 of
the
valve assembly 220a (i.e., the valve bore) can continue to be controlled
without
regard of the fluid flow and hydraulic pressure to the exterior of the valve
assembly
220a. During the delay period, it is therefore possible, in one example
embodiment,
to hydraulically operate other components present on the tubular string 215,
for
example components distally located on the tubular string 215 relative to the
valve
assembly 220a, such as another valve assembly (not shown) or a packer (not
shown). During the delay period, such tools can be hydraulically operated to
cause
a shift from a first operable position to a second operable position. Thus,
for
example, during the delay period, a hydraulically operable valve, for example,
a
valve located distally on the tubular string from valve assembly 220a, may be
operated to shift from a port-closed position to a port-open position or vice-
versa,
or a hydraulically operable isolation element, such as a packer, may be
operated
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to shift from a position where the isolating element forms a seal between a
wellbore
and a wellbore liner to another position in which the seal is broken, or vice-
versa.
[0090] Turning now to FIGS. 5A-5B, shown therein is the valve assembly 220a,
upon completion of degradation (i.e., disintegration) of the degradable
barrier 360.
Plugs 381 and 382 have also been displaced, which can be achieved by applying
a fluid flow at low hydraulic pressure to the valve bore 302. Referring now to
FIGS.
4B-4C, again in conjunction with FIGS. 5A-5B. Plugs 381 and 382 in the current
example embodiment are separate metal cylinders that carry seals 444 and 445
on their periphery to ensure a fluid tight seal against the walls of port
apertures
398 and 399. Plugs 381 and 382 can provide protection to the degradable
barrier
360 from the hydraulic pressure that is applied to shift the valve assembly
220a
from a port-closed position to a port-open position. Thus, it is possible to
apply fluid
flows in the inner bore 216 of the tubular string 215 at hydraulic pressures
well in
excess of the pressures used to inject fluid into the rock formation following
disintegration of the barrier 360. For example, shifting pressures (i.e.,
pressure
required to actuate the shiftable valve assembly 220a from a port closed
position
to a port open position) may be in excess of 1,000 psi, in excess of about
1,500
psi, in excess of about 2,000 psi, in excess of about 3,000 psi, or in excess
of
about 4,000 psi, or for example from about 1,000 psi to about 3,000 psi. Once
the
degradable barrier 360 has disintegrated, fluid flows applied from the valve
bore
302 can displace the plugs 381 and 382 radially outward into the space
previously
occupied by the degradable barrier 360 and the second tubular member 310.
Fluid
(F) can flow from the interior of the valve bore 302 through the incrementally
narrowing portion 446 (see: FIG. 5C) and wider portion of the port apertures
398
and 399 into the annulus 210, or vice-versa. Plugs 381 and 382 can be made of
any material suitable for operation under wellbore conditions, or they may be
optional. Thus, for example, in one embodiment, plugs may absent, and the
degradable barrier may be protected from degradation by fluids in the valve
interior
by a surface coating applied to the interiorly disposed surface area of the
degradable barrier. Upon disintegration of the barrier, the surface coating
will break
as fluid pressure is applied.
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[0091] The shiftable valve assembly of the present disclosure is particularly
useful to fluid-treat a rock formation using fluid flows at modest hydraulic
pressures, notably fluid flows at hydraulic pressures sufficient to form a
fluid-front
to thereby displace hydrocarbons from a hydrocarbon bearing rock formation.
This
is because after a higher hydraulic pressure is used to expose a degradable
barrier
so that the degradable barrier disintegrates, fluid flows at lower hydraulic
pressures
can be used to interact with the hydrocarbon formation. Fluid flows at
hydraulic
pressures sufficient to a form a fluid-front include pressures less than about
1,000
psi; less than about 750 psi; less than about 500 psi; less than about 400
psi; less
than about 300 psi; less than about 200 psi; and less than about 100 psi; or
from
about 100 psi to about 1,000 psi. Under such hydraulic pressures, fluid can
migrate
through a rock formation surrounding at a volumetric flow rate of, for
example, from
about 20 m3/day to about 120 m3/day. In this manner, the shiftable valve
assembly
may be implemented according to effect a fluid flow in a hydrocarbon bearing
rock
formation disclosure as further illustrated in an example embodiment in FIGS.
7A-
7D.
[0092] Referring now to FIGS. 7A-70, shown therein is an example well
configuration 700 including a wellbore 709 having a proximal end p and distal
end
d and a zone 701 in the hydrocarbon bearing rock formation 205 identified for
low
pressure fluid treatment. Following the establishment of fluid communication
between the tubular string 715 and the rock formation 205, operating a valve
assembly 220 as hereinbefore described, a fluid flow (F) having a hydraulic
pressure sufficient to form a fluid-front can be set up at surface 707. The
fluid flow
F can exit the valve assembly 220 to establish a migrating and expanding fluid
front 702 within the treatment zone 701 of rock formation 205. As the fluid
front
702 migrates outward in a more or less radial direction into the rock
formation 205
surrounding the valve 220, the fluid front 702 displaces hydrocarbons present
in
the treatment zone 701, allowing a hydrocarbon flux to develop, including a
hydrocarbon flux (H) towards the wellbore 709. The hydrocarbons entering the
wellbore 709 may be recovered at surface 707.
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[0093] In another aspect, the present disclosure relates to processes for
controlling fluid flow in a subterranean well. Accordingly, the present
disclosure
further provides, in one broad aspect, in at least one example embodiment, a
process for controlling fluid flow in a tubular string (also referred to as a
wellbore
string), the process comprising: installing a tubular string 215 in a wellbore
202
and applying fluid flows to the inner bore 216 of the tubular string 215.
[0094] The process begins with installing a tubular string 215 in a wellbore
202.
The tubular string 215 has an inner bore 216 (also referred to as a central
bore)
therethrough and includes a shiftable tubular valve assembly 220 (also
referred to
as a side-ported two member tubular valve assembly) interconnecting two
successive portions of the tubular string 215. The valve assembly 220 has a
first
tubular member 305 (which has a port) and a second tubular member 310. The
valve assembly 220 is shiftable from a port-closed position to a port-open
position
and has a fluid degradable barrier 360 covering the port. The degradable
barrier
360 is covered by the first tubular member 305 in the port-closed position to
prevent fluid contact between the exterior of the valve assembly 220 and the
degradable barrier 360.
[0095] The process continues with applying fluid flows to the inner bore 216
at
sufficient hydraulic pressures to cause changes to the valve assembly 220.
These
various pressures can be determined experimentally or by mounting sensors at
locations of the valve assembly 220 to confirm that the changes have occurred.
One change is to cause the valve assembly 220 to shift from the port-closed
position to the port-open position. Another change is to expose the degradable
barrier 360 to the exterior of the valve assembly 220 to permit fluid contact
between
the degradable barrier 360 and fluid to the exterior of the valve assembly
220.
Another change is to degrade the degradable barrier 360 during a delay period
until the degradable barrier 360 is disintegrated. Another change is to
establish
fluid communication between the inner bore 216 and the exterior of the valve
assembly 220 when the degradable barrier 360 is disintegrated.
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[0096] In at least one embodiment, the process can further include applying a
first fluid flow at a first hydraulic pressure sufficient to cause the valve
assembly
220 to shift from the port-closed position to the port-open position, and then
applying, after the degradable barrier 360 has disintegrated, a second fluid
flow at
a second hydraulic pressure to establish fluid communication between the inner
bore 216 and the exterior of the valve assembly 220.
[0097] In at least one embodiment, the second fluid flow at the second
hydraulic
pressure can further be sufficient to form a fluid-front in a hydrocarbon-
bearing
rock formation surrounding the valve assembly 220 to displace hydrocarbons
from
the rock formation into the wellbore 202.
[0098] In at least one embodiment, the first hydraulic pressure can be higher
than
the second hydraulic pressure.
[0099] In at least one embodiment, the first hydraulic pressure can be in
excess
of about 1,000 psi, in excess of about 1,500 psi, in excess of about 2,000
psi, in
excess of about 3,000 psi, or in excess of about 4,000 psi, and the second
hydraulic pressure can be less than about 1,000 psi; less than about 750 psi;
less
than about 500 psi; less than about 400 psi; less than about 300, psi; less
than
about 200 psi; or less than about 100 psi.
[00100] In at least one embodiment, the process can further include, during
the
delay period, hydraulically shifting at least one other hydraulically
controllable
component installed on the tubular string 215 together with the valve assembly
220 from a first operable position to a second operable position.
[00101] In at least one embodiment, the tubular string 215 comprises two or
more
of the side-ported valve assemblies of the present disclosure separated from
one
another by a portion of the tubular string 215, for example, 3, 4, 5, 6, 7, 8,
9, 10, or
more side-ported valve assemblies. The process can then further include
applying
fluid flow at a sufficient pressure to the inner bore 216 to cause each of the
two or
more side-ported valve assemblies to shift from the port-closed to the port-
open
position. Such shifts may be effected more or less simultaneously, or
sequentially.
In one embodiment, in which a first and second shift are effected
sequentially, a
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first shift may result in a first valve assembly 220a to be shifted from a
port-closed
position to a port-open position, and following disintegration of the
degradable
barrier 360 (and the concomitant expiration of the delay period) of the first
valve
assembly 220a, a second shift may result in a second valve assembly 220b to be
shifted from a port-closed position to a port-open position.
[00102] In at least one embodiment, the tubular string 215 can be installed in
a
wide-diameter tubular string 620, which is another, larger diameter wellbore
string.
[00103] In at least one embodiment, the wide-diameter tubular string 620
includes
other side-ported valves 615, and upon establishing fluid communication
between
the inner bore 216 and the valve assembly 220, further fluid communication is
established between the valve assembly 220 and the wellbore 202 via the side
ports of the other side-ported valves 615.
[00104] Turning to FIG. 6 now, shown therein is an example well arrangement
600. Well arrangement 600 contains a wellbore 605 in which has been installed
a
wide-diameter tubular string 620. The wide-diameter tubular string 620
contains a
side-ported valve 615. The side-ported valve 615 may have been used to
fracture
rock formation 205 and extract hydrocarbon from the rock formation 205. Upon
having completed the hydrocarbon recovery from the fracturing operation, the
ports 610 of the side-ported valve 615 were left in a port-open position;
alternatively, the ports 610 were left in a port-closed position and are now
opened.
In order to perform an enhanced recovery operation, a narrow-diameter tubular
string 625 can be installed inside the wide-diameter tubular string 620. The
narrow-
diameter tubular string 625 contains the valve assembly 220 of the present
disclosure. In some embodiments, the narrow-diameter tubular string 625 can be
inserted in such a manner that the valve assembly 220 is positioned in close
proximity to the side-ported valve 615, for example so that the valve assembly
220
and the side-ported valve 615 are spaced apart less than about 10 meters, less
than about 5 meters, or less than about 2 meters from one another. This may be
achieved in particular when it is known where in the wellbore 605 (i.e., at
what
depth) the side-ported valve 615 is located, for example, based on information
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relating to the prior fracturing operation for which the side-ported valve 615
was
used. The narrow-diameter tubular string 620 can then be designed to include
the
valve assembly 220 at a position within the narrow-diameter tubular string
620, so
that the narrow-diameter tubular string 620 can be inserted in a manner that
allows
valve assembly 220 to become positioned in close proximity of the side-ported
valve 615. Accordingly, the insertion can then be performed using a
methodology
that allows the determination of the depth of the side-ported valve 615 to be
made,
for example, by measuring the length of the section of wellbore liner between
valve
assembly 615 and the surface, or using other known methodologies.
[00105] In another embodiment, the narrow-diameter tubular string can be
inserted within the wide-diameter tubular string so that upon completion of
the
insertion, the valve assembly 220 is not located distally or proximally
relative to the
side-ported valve 615, but instead is inserted therein.
[00106] The valve assembly 220 can then be actuated and shifted from a port-
closed position to a port-open position as hereinbefore described. Upon
disintegration of the fluid degradable barrier (not shown) of the valve
assembly
220, a low-pressure fluid flow can be established from the surface through the
side
ports (not shown) of valve assembly 220 and the ports 610 of side-ported valve
615, and a fluid-front can be formed within rock formation 205 surrounding the
side-ported valve 615. Displacement of the hydrocarbon results in flow of the
hydrocarbon to the wide-diameter tubular string 620 and narrow diameter
tubular
string 625 whence the hydrocarbon can be recovered at surface.
[00107] In further different embodiments, the wide-diameter tubular string 620
can
include a plurality of side-ported valves 615, and the narrow-diameter tubular
string
625 can contain a corresponding plurality of valve assemblies 220 that each
interact with one of the side-ported valves 615. In some embodiments, upon
installation of the narrow-diameter tubular string 625, two or more valve
assemblies 220 may be spaced closely to two or more side-ported valves 615,
and
different zones of the rock formation 205 may be treated sequentially as
hereinbefore described.
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[00108] As can now be appreciated, the various embodiments of the valve
assembly described herein can be conveniently used to control fluid flow in
wells
by using modest pressure levels to provide enhanced hydrocarbon recovery and,
optionally to hydraulically control other components in a wellbore. The
various
.. embodiments of the valve assembly described herein can be applied in
various oil
or gas extraction processes.
[00109] The above disclosure generally describes various aspects of various
example embodiments of apparatuses and processes of the present disclosure. It
will be appreciated by a person skilled in the art having carefully considered
the
above description of representative example embodiments of the present
disclosure that a wide variety of modifications, amendments, adjustments,
substitutions, deletions, and other changes may be made to these specific
example embodiments, without departing from the scope of the present
disclosure.
Accordingly, the foregoing detailed description is to be understood as being
given
by way of example and illustration only, the spirit and scope of the present
disclosure being limited solely by the appended claims.
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