Note: Descriptions are shown in the official language in which they were submitted.
METHODS FOR ESTABLISHING FLUID COMMUNICATION
BETWEEN A SAGD WELL PAIR
This application is a divisional application of Canadian Patent Application
No. 2,847,141, filed on
March 21, 2014.
FIELD
[00011 The present disclosure relates to methods for effecting fluid
communication between
two wells in a hydrocarbon containing reservoir.
BACKGROUND
[0002] Steam Assisted Gravity Drainage (SAGD) uses a pair of wells to
produce a
hydrocarbon from a hydrocarbon containing reservoir. Typically the well pair
includes two
horizontal wells vertically spaced from one another, with the upper well used
to inject steam into
the reservoir and the lower well to produce the hydrocarbon. The steam
operates to generate a
steam chamber in the reservoir, and thermal heat from the steam operates to
lower the viscosity of
the hydrocarbon, allowing for gravity drainage, and thereby production from
the production well.
Typically, before production commences from the production well, a "start-up"
period is required
to warm the interwell region of the reservoir between the two wells. Heating
to a mobility
threshold enables displacement of the viscous hydrocarbon from the interwell
region to result in
effective fluid communication between the injection well and the production
well.
[0003] Steam circulation during the start-up period to pre-heat SAGD well
pairs is a routine
yet challenging process. Steam circulation may be hydraulically difficult to
start or sustain and
the circulation effort may be adversely affected by reservoir heterogeneity
near the wellbore or
between the injector and producer. Non-uniform heating of the wellbore, and
interwell region of
the hydrocarbon containing reservoir during steam circulation results in less
than optimal SAGD
production from the reservoir and higher SOR (steam to oil ratio). Also, steam
circulation may
not always be suitable for SAGD start-up where the reservoir is relatively
shallow, confined by
weak or non-existent cap-rock.
[0004] Another challenge with steam circulation as a start-up technique
results from the delay
between drilling the well pairs and the availability of surface facilities to
provide steam to the wells.
Generally, after SAGD well pairs have been drilled and completed, surface
facilities
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are constructed to enable utilization of steam from a steam generation
facility within the SAGD
well pair. There can be a significant time elapse after the well pair is
drilled until these facilities
to provide steam are constructed. Elapsed time varies but delays can be up to
two years.
SUMMARY
100051 In one aspect, a method of establishing fluid communication in an
interwell region
between an injection well and a production well forming the well pair includes
electrically
heating the interwell region between injection well and production well.
[0006] In some implementations, the electrical heating of the interwell
region is effected by
an electrical heating system disposed within the injection well and/or the
production -well.
[0007] In another aspect, a method of producing bitumen from an oil sands
reservoir
includes, during a start-up phase, electrically heating an interwell region of
the oil sands
reservoir disposed between an injection well and a production well, for
establishing a fluid
communication between between the injection well and the production well.
After establishing
the fluid communication, a production phase is commenced that includes
injecting steam from
the injection well into the oil sands reservoir for effecting mobilization of
bitumen within the oil
sands reservoir. The mobilized bitumen is conducted through the interwell
region to the
production well and recovered to surface through the production well.
[0008] In some implementations, the method further includes, after
establishing fluid
communication in the interwell region, supplying steam from a steam generator,
where the steam
being injected is the steam supplied from the steam generator. Electrically
heating the interwell
region can be completed prior to, or substantially completed prior to,
commissioning of steam
facilities for effecting the supplying of steam from the steam generator to
the injection well.
[0009] The electrical heating of the interwell region can be effected while
steam facilities,
for effecting the supplying of stearn from the steam generator to the
injection well, are being
constructed.
[00101 The electrical heating of the interwell region can be effected by an
electrical heating
system disposed within the injection well and/or the production well.
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[00111 The interwell region can be defined within a shallow hydrocarbon
reservoir.
[0012] The interwell region is the region of the reservoir that is between
the injection well
and the production well, which in a typical SAGD operation is approximately 5
metres in depth.
In some reservoirs, the bitumen saturation is greater than 85% and the
porosity is greater than
35%, although reservoirs vary in these characteristics and the bitumen
saturation and/or porosity
could be lower in some instances.
[00131 In another aspect, a method of establishing fluid communication
between a well
pair within an oil sands reservoir includes electrically heating an interwell
region of the oil sands
reservoir disposed between an injection well and a production well, to at
least contribute to
establishing fluid communication in the interwell region. The electrical
heating includes:
electrically heating a first portion of the interwell region at a first
predetermined heating rate; and
electrically heating a second portion of the interwell region at a different
second predetermined
heating rate while the first portion is being heated at the first
predetermined rate.
[00111] In some implementations, the first predetermined heating rate and
the second
predetermined heating rate are selected to effect a substantially uniform
heating of the interwell
region.
[00151 In some implementations, the electrical heating of an interwell
region is effected by
an electrical heating system disposed within at least one of the injection
well and the production
well.
[0016] In another aspect, a method of establishing fluid communication
between a well
pair comprising an injection well and a production well within an oil sands
reservoir includes
heating an interwell region disposed between the injection well and the
production well,
establishing fluid communication between the two wells. The heating includes
heating the
interwell region with heat generated by steam injected into at least one well
in the well pair and
simultaneously with heat generated by an electric heating system. Heat
generated by the electric
heating system effects both heating of the interwell region and heating of the
injected steam.
[0017] In some implementations, the steam injected into the at least one
well is injected
into the well and circulated to surface.
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[0018] In some implementations, the steam injected into the at least one
well is injected
into the reservoir, i.e., bull heading.
[0019] In some implementations, the steam carries a gaseous chemical
additive material
and condensation of the chemical additive material is mitigated by the
electric heating of the
steam.
[0020] In some implementations, the electric heating system is disposed
within at least one
of the wells in the well pair.
[0021] In another aspect, a method method of producing bitumen from an oil
sands
reservoir includes, after a fluid communicating interwell region has been
established between
and injection well and a production well forming a well pair, injecting steam
into the oil sands
reservoir via the injection well for effecting mobilization of bitumen within
the oil sands
reservoir. The mobilized bitumen is conducted through the established fluid
communicating
interwell region to the production well. While the steam is being injected,
the injected steam is
heated with an electrical heating system situated in the injection well. The
mobilized bitumen is
recovered to surface through the production well.
(0022) In some implementations, the injected steam carries a gaseous
chemical additive
material, and the electrical heating of the injected steam is such that
condensation of the
chemical additive material is mitigated.
100231 In some implementations, prior to the injecting steam for effecting
mobilization, the
interwell region is electrically heated with the electrical heating system,
which at least
contributes to establishing a fluid communicating interwell region for
effecting fluid
communication between the injection well and the production well.
[0024] In another aspect, a method of producing bitumen from an oil sands
reservoir
includes electrically heating an interwell region, of the oil sands reservoir,
disposed between an
injection well and a production well established within the oil sands
reservoir, with an electrical
heating system. After the fluid communicating interwell region has been
effected, steam assisted
gravity drainage (SAGD) is conducted to produce the bitumen, wherein the SAGD
includes:
injecting steam into the oil sands reservoir via the injection well for
effecting mobilization of
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bitumen disposed within the oil sands reservoir such that the mobilized
bitumen is conducted
through the established fluid communicating interwell region to the production
well; and
recovering the mobilized bitumen through the production well. While SAGD is
being
conducted, a problem is detected requiring well intervention. In response to
the detecting of the
problem requiring well intervention, SAGD is suspended and the wellbore fluids
disposed within
one or both of the wells are electrically heated with the electrical heating
system. The wellbore
fluids are vaporized and are conducted through the respective well to the
wellhead.
[0025] In some implementations, the electrical heating system is disposed
in the injection
well and/or the production well.
[0026] In another aspect, a method of producing bitumen from an oil sands
reservoir
includes establishing fluid communication between an injection well and a
production well for
use as a steam assisted gravity drainage (SAGD) well pair by exclusively using
electrical heat
applied in situ. The method can further include, only after establishing the
fluid communication,
commencing injcction of steam into the oil sands reservoir via the injection
well and producing
production fluid from the oil sands reservoir via the production well, wherein
the production
fluid includes bitumen.
BRIEF DESCRIPTION OF DRAWINGS
[0027] The preferred embodiments will now be described with the following
accompanying drawings, in which;
[0028] Figure 1 is a schematic illustration of a well pair in an oil sands
reservoir, where
fluid communication between the pair is to be established by embodiments of
methods described
herein;
[0029] Figure 2 is a schematic illustration of a Mineral Insulated ("MI")
heater cable;
[0030] Figure 3 is a schematic illustration of a system for deploying an
electrical heating
system within a wellbore for enabling practising of methods described herein;
[0031] Figure 4 is a cross-sectional view of a coiled tube, from one end,
including three MI
heater cables illustrated in Figure 2; and
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100321 Figure 5 is a cross-sectional side view of a coiled tube, including
three MI heater
cables illustrated in Figure 2.
DETAILED DESCRIPTION
100331 There is provided a method for effecting fluid communication between
a pair of
wells within a hydrocarbon containing reservoir during the start-up phase of a
SAGD operation.
The wells are separated by an interwell region of the reservoir. For
illustrative purposes below,
an oil sands reservoir from which bitumen is being produced is described.
However, it should be
understood, that the techniques described could be used in other types of
hydrocarbon containing
reservoirs where SAGD is employed.
[0034] Referring to Figure 1, in a typical SAGD well pair, the wells are
spaced vertically
from one another, such as wells 10 and 20, and the vertically higher well,
i.e., well 10, is used for
steam injection during a production phase of the SAGD operation, and the lower
well, i.e., well
20, is used for production during the production phase. In a conventional
start-up phase, steam is
circulated through both wells 10 and 20, for the purpose of warming the
interwell region 15
primarily by conduction. As the interwell region 15 warms, the viscosity of
the bitumen
contained in that region is reduced, mobilizing the bitumen which can then be
produced from the
production well 20.
[0035] In the implementation shown, a cased-hole completion includes casing
40 run down
the wellbore 10 and 20 through the production zone. The casing may be cemented
to the
subterranean oil sands reservoir for effecting zonal isolation. A liner may be
hung from the last
section of casing. The liner can be made from the same material as the casing
string, but, unlike
the casing string, the liner does not extend back to the wellhead. The liner
is slotted or
perforated to effect communication with the reservoir.
[0036] Fluid conducting tubing 50 or multiple tubing strings can be
installed inside the last
casing string of the injection well, well 10. The tubing(s) 50 is provided to
conduct steam and
steam condensate from the wellhead 60 to the liner and sequentially to the
reservoir.
100371 Fluid conducting tubing 50 or multiple tubing strings can be
installed inside the last
casing string of the production well, well 20.
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[0038] In the
illustrated embodiment, a perforated liner is provided in each of the wells
10,
20, for enabling fluid communication between the tubing 50 and the reservoir
30. During the
production phase of the SAGD operation, steam injected through the well 10
(typically referred
to as the "injection well") is conducted within the tubing or casing annulus
or both, through the
liner, and into the reservoir 30. The injected steam mobilizes the bitumen
within the oil sands
reservoir 30. The mobilized bitumen and steam condensate drains through the
interwell region
15 by gravity to the well 20 (typically referred to as the "production well"),
collects in the liner
and is surfaced through tubing 50 or by artificial lift to the surface 5.
[0039] Prior to
the production phase, the fluid communication between the wells 10, 20 is
established through the interwell region 15 during a start-up phase. Unlike
the conventional
start-up technique, which relies solely on steam to achieve fluid
communication, techniques and
systems are described where fluid communication between the injection well 10
and the
production well 20 is enabled by electrical heating of the interwell region
15. An in situ
electrical heat source raises temperature uniformly, or substantially
uniformly, along the
wellbore installation and heats the surrounding reservoir by conduction.
Electrical heating of the
interwell region 15 is more uniform, relative to steam circulation. As well,
in comparison to
using steam circulation for start-up, the heat generated within the interwell
region by electrical
sources can be easier to control. This is because heating of the interwell
region responds faster
to modulation of electrical sources than it does for modulation of steam
sources.
[0040] A
typical wellbore includes cement between the casing and the reservoir
material.
Cement integrity can be compromised by pronounced thermal cycling and/or
abrupt transitions
of heating rates in situ. Electrical heat provides a controllable heat source
that can avoid or
reduce these events, and cement integrity is more likely to be maintained for
a longer period of
time, than in a well pair relying solely on steam circulation for start-up.
[0041] In a
typical SAGD operation, there are multiple well pairs drilled into the
reservoir.
After the well pairs are drilled and completed, surface facilities must be
built before the SAGD
operation can commence. The surface facilities may include steam generating
units or steam
distribution pipelines and manifolds. Until the steam generating units are
complete, there is no
source of steam and the start-up phase cannot commence. Advantageously, when
using
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electrical heat as the heat source for the start-up phase, the start-up phase
can commence at any
time after the well pairs are completed and prior to completion of the surface
facilities.
Considering the time that can elapse between the well pairs being drilled and
the surface
facilities being completed can be two or more years, a significant time
advantage can be realized
by employed electrical heat.
[0042] In some implementations, electrical heat is the sole source of heat
during the start-
up phase, and fluid communication in the interwell region 15 can be enabled
without any
circulation of steam in the injection well 10 or the production well 20. In
other implementations,
electrical heat is employed as the initial source of heat during the start-up
phase, and particularly
while a steam source is unavailable. Once surface facilities including a steam
source are
complete, a final stage of the start-up phase can include both electrical heat
and steam injection
to displace highly viscous hydrocarbons from interwell region 15. In other
implementations
electrical heat in the production well 20 and steam circulation in the
injection well 10 could be
applied for heating interwell region 15 . In other implementations, electrical
heat is employed as
the initial source of heat, and once surface facilities including a steam
source unit are complete,
the final stage of the start-up phase is by steam circulation only, e.g., in
one or both of the wells
10, 20, In any of these implementations, by employing electrical heat as a
start-up phase heat
source during the time period when steam was unavailable, start-up is achieved
sooner than
would have been the case if relying on steam only. Accordingly, the SAGD
operation can move
into the production phase sooner. By accelerating start-up of SAGD, pad
economics are
improved by virtue of the earlier production of bitumen. Additionally, start-
up can be achieved
using significantly less steam, resulting in an improved SOR.
[00431 In some embodiments, the electrical heating is by an electrical
heating system that
is disposed in the injection well and/or the production well. In addition to
an electrical heater or
an electrical heating system, heating can be by one or more other artificial
sources of heat. That
is, in addition to electrical heating of the interwell region 15, one or more
other artificial sources
of heat can supply heat to the interwell region 15, such that the heating in
the interwell region 15
is caused by heat supplied by the electrical heating as well as heating by the
other artificial
sources of heat. Where, in addition to an electrical heater or an electrical
heating system, there is
at least one or more other artificial sources of heat that is supplying the
heat to the interwell
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region 15, each one of the multiple artificial sources of heat may be
supplying the heat to the
interwell region 15 independently of one another or in co-ordination or
controlled co-operation
with one or more of the other heat sources. Also, each one of the multiple
sources of heat may
be supplying the heat to the interwell region 15 simultaneously with one or
more of the other
heat sources, asynchronously relative to one or more of the other heat
sources, or any
combination thereof. An example of another artificial source of heat is steam.
In this respect,
heating of the interwell region 15 can also be caused by steam injection
through one or both of
the wells 10, 20. In some implementations, the steam injection is effected by
steam circulation
within the well. In such case, the steam is injected through a fluid passage
provided within the
well (such as, for example, the fluid conducting tubing 50) to the toe of the
well, becomes
disposed in thermal communication with the reservoir 30 and effects heating of
the interwell
region 15, and is then returned to the surface 5 through another fluid passage
defined within the
well (such as, for example, the annulus between the tubing 50 and the casing
40). In other
implementations, the steam injection is effected by bullheading. In such case,
the steam is
injected through a fluid passage provided within the well (such as, for
example, the fluid
conducting tubing and/or the annulus between the tubing 50 and the casing 40)
and supplied to
the reservoir 30.
100441 In some implementations, the interwell region is defined within a
shallow
hydrocarbon reservoir that includes bitumen. A shallow hydrocarbon reservoir
is a hydrocarbon
reservoir that is disposed less than 140 metres from the surface. For shallow
hydrocarbon
reservoirs, using conventional steam circulation to establish fluid
communication between the
wells 10, 20 can create environmental risks, as the steam pressure may effect
fractures within the
oil sands reservoir 30, and thereby effect conduction of the bitumen and/or
steam to undesirable
locations within the oil sands reservoir 30, or to surface. In this respect,
by using electrical
system to heat the interwell region 15 and enable displacement of immobile
bitumen between the
wells 10, 20, the risk of damaging the oil sands reservoir 30, or causing
undesirable surface
releases of bitumen or steam, is avoided.
100451 In another aspect, the interwell region 15 is defined within a poor
geology
reservoir. A poor geology reservoir is a reservoir with a bitumen saturation
of less than 85% and
a porosity of less than 30%. Bitumen saturation of a reservoir is the mass
concentration of
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bitumen within the reservoir. Porosity of a reservoir is the volumetric
fraction of empty space
within the reservoir, expressed as a percentage. It can be desirable to use
electrical heating to at
least partially contribute to the establishment of fluid communication through
such an interwell
region 15 during the start-up phase, rather than solely relying on steam to
establish the fluid
communication. This is because it is relatively difficult for steam to be
conducted through a
poor geology reservoir. Comparatively, the establishment of fluid
communication through the
interwell region 15 in a poor geology reservoir is faster when electrical
heating is used to heat
such interwell region 15.
[0046] In some implementations, different portions of the interwell region
15 are
independently electrically heated so as to differentially mobilize the fluid
within interwell region
15. Electrically heating the interwell region 15 can include electrically
heating a first portion of
the interwell region 15 at a first predetermined heating rate and, while the
first portion is being
electrically heated at the first predetermined heating rate, electrically
heating a second portion of
the interwell region at a different second predetermined heating rate. It can
be desirable to
independently control the rate of heating of one or more portions of the
interwell region 15 from
the rate of heating of one or more other portions of the interwell region 15
if some portions have
different thermal characteristics (e.g. thermal conductivity and heat
capacity) than other portions
and therefore, require different rates of heating to achieve uniform (or
substantially uniform)
temperature conditions.
[0047] In some implementations, heating of the interwell region 15 is by at
least both: (i)
electrical heating and (ii) steam injection through one or both of the
injector and production
wells. In such implementations, steam is injected through at least one of the
wells 10, 20 while
electrically heating the interwell region 15 with an electrical heating
system, disposed within a
respective one or more of the wells 10, 20 through which the steam is being
injected. In this
respect, the injected steam is also heated by the electrical heating system.
The heating of the
steam can improve or maintain steam quality. In some implementations, the
steam injection is
effected during steam circulation. In other implementations, the steam
injection is effected while
bullheading.
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[0048] In some
embodiments, for example, during start-up, the injected steam carries a
gaseous chemical additive material for supply to the interwell region 15. The
gaseous chemical
additive material is configured for promoting establishment of the fluid
communicating interwell
region 15. Suitable chemical additives include a surface tension adjusting
agent, such as a
detergent. A surface tension adjusting agent would be configured for affecting
the surface
tension between the bitumen and the rock such that separation of the bitumen
from the rock is
facilitated. Suitable
chemical additives include cationic surfactants, such as
alkyltrimethylammonium bromide and alkyldimethylammonium bromide. Other
suitable
chemical additives include alcohol propoxylate sulfate and alkyl sulfonate
surfactants. Further
suitable chemical additives include hydrocarbon materials, such as butane,
propane or diesel.
Such hydrocarbon materials arc provided for enhancing the mobility of the
bitumen within the
reservoir. In this respect, in addition to the injected steam being heated by
the electrical heating
system, where the injected steam is carrying the gaseous chemical additive
material, the gaseous
chemical additive material is also heated by the electrical heating system,
such that condensation
of the gaseous chemical additive material is prevented or at least mitigated,
and that the chemical
additive material remains in the gaseous phase so its supply to the reservoir
is enabled.
[0049] In
another aspect, an electrical heating system disposed within at least one of
the
injector and production wells 10, 20, at least partially contributes to
heating of the interwell
region 15. After the interwell region 15 has been heated to effect, SAGD is
conducted, and
SAGD includes injecting steam from the injection well 10 into the oil sands
reservoir 30 for
mobilizing bitumen within the oil sands reservoir 30 such that the mobilized
bitumen is
conducted through the interwell region 15 to the production well 20, and
recovering the
mobilized bitumen through the production well 20. While SAGD is being
conducted, a problem
may be detected requiring well intervention. Well intervention may be
required, for example, to
replace downhole equipment or instrumentation, such as submersible pumps, long
tubing,
plugged components, or optical fibre. In response to the detecting of the
problem, SAGD is
suspended so as to permit well intervention. After the suspending of SAGD,
wellbore fluids
within one or both of the wells 10, 20 may be conducted to the surface by
electrically heating the
wellbore fluids with the electrical heating system, such that the wellbore
fluids are vaporized and
are conducted through the respective well 10 or 20 to the surface 5. In some
embodiments, for
example, the electrical heating system may have also been used to heat the
steam being supplied
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to the injection well 10 during SAGD. By enabling conduction of the wellbore
fluids in this
manner, use of pumping units or other lifting mechanism can be avoided. As
well, removal of
the wellbore fluids using electrical heaters is more effective than by using
pumping units or other
lift mechanisms, and thereby mitigates the risk of possible undesirable
chemical reactions
between residual wellbore fluids and fluids being introduced to the wellbore
during well
intervention.
[0050] In some embodiments, for example, the electrical heating is by an
electrical heating
system. In some of these embodiments, for example, an electrical heating
system is disposed in
one or both of the wells 10. In some of these embodiments, for example, the
electrical heating
system includes a heater cable. The heater cable includes a wire surrounded by
insulation (e.g.
mineral insulation) and disposed within a metallic sheath. The wire is
electrically coupled to a
power source and a controller and, in this respect, is configured to effect
heating of the interwell
region 15 by conduction. An example of a suitable heater cable is a mineral-
insulated ("MI")
heater cable 70. Referring to Figure 2, a MI heater cable 70 includes an
electrically conducting
core 72, surrounded by a metallic sheath 74 (for example, a 304L sheath) with
a mineral
insulation layer 76 (for example, magnesium oxide) disposed between the
metallic sheath 74 and
the core 72. In some embodiments, for example, the heater cable 70 can include
relatively hotter
and relatively colder sections. This is enabled by using different materials
in different sections
of the cable. In this respect, by having relatively hotter and relatively
colder section, different
heating rates can be provided for different portions of the interwell region
15 in some
embodiments.
[0051] Referring to Figure 3, in some of these embodiments, for example,
the heater cable
is deployed within a coiled tube 60. Referring to Figures 4 and 5, in some
embodiments, for
example, multiple cables 70 are deployed within the coiled tube 60. In some
embodiments, for
example, the cables 70 are mounted to a support rod 80 for maintaining
positioning the cables
70. In the illustrated embodiment, for example, the heater cable is a three
(3) phase heater
consisting of three (3) single conductor MI heater cables 70 disposed in a
coiled tube 60 that is
deployed from a reel 90 disposed on the surface 5. The MI heater cables 70 are
assembled into
complete heater units by installing a wye splice 100 at the bottom of the
cables 70 for forming a
dielectrically insulated connection.
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[0052] Other
forms of electrical heating devices can be used, and are not limited to those
discussed herein.
[0053]
Reference throughout the specification to "one embodiment," "an embodiment,"
"some embodiments," "one aspect," "an aspect," or "some aspects" means that a
particular
feature, structure, method, or characteristic described in connection with the
embodiment or
aspect is included in at least one embodiment of the present invention. In
this respect, the
appearance of the phrases "in one embodiment" or "in an embodiment" or "in
some
embodiments" in various places throughout the specification are not
necessarily all referring to
the same embodiment. Furthermore, the particular features, structures,
methods, or
characteristics may be combined in any suitable manner in one or more
embodiments.
[0054] Each
numerical value should be read once as modified by the term "about" (unless
already expressly so modified), and then read again as not so modified unless
otherwise
indicated in context. Also, in the sumrnary arid this detailed description, it
should be understood
that a concentration range listed or described as being useful, suitable, or
the like, is intended that
any and every concentration within the range, including the end points, is to
be considered as
having been stated. For example, "a range of from 1 to 10" is to be read as
indicating each and
every possible number along the continuum between about 1 and about 10. Thus,
even if specific
data points within the range, or even no data points within the range, are
explicitly identified or
refer to only a few specific data points, it is to be understood that
inventors appreciate and
understand that any and all data points within the range are to be considered
to have been
specified, and that inventors have disclosed and enabled the entire range and
all points within the
range.
[0055] In the
above description, for purposes of explanation, numerous details are set forth
in order to provide a thorough understanding of the present disclosure.
However, it will be
apparent to one skilled in the art that these specific details are not
required in order to practice
the present disclosure. Although
certain dimensions and materials are described for
implementing the disclosed example embodiments, other suitable dimensions
and/or materials
may be used within the scope of this disclosure. All such modifications and
variations, including
- all suitable current and future changes in technology, are believed to be
within the sphere and
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scope of the present disclosure.
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