Note: Descriptions are shown in the official language in which they were submitted.
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REAL-TIME FIELD FRICTION REDUCTION METER AND METHOD OF USE
BACKGROUND
[0001] Hydrocarbon-producing wells often are serviced by a variety of
operations involving
introducing a servicing fluid into a portion of a subterranean formation
penetrated by a
wellbore. Examples of such servicing operations include a fracturing
operation, a hydrajetting
operation, an acidizing operation, or the like. In providing such a servicing
fluid to the
subterranean formation, it is often desirable to employ a friction reducer to
lessen the friction
between the servicing fluid and the conduit through which the servicing fluid
is communicated
to the formation.
[0002] Servicing fluids and the components comprising those servicing fluids
are diverse.
As such, a given friction reducer may not be compatible with a given servicing
fluid and,
therefore, may be ineffective to reduce the friction between the servicing
fluid and the conduit
through which the servicing fluid is communicated to the subterranean
formation. Further,
because the constituents and the relative amounts of those constituents of a
servicing fluid may
be changed or varied over the course of a servicing operation, the
effectiveness of a given
friction reducer may vary over the course of a servicing operation. As the
effectiveness of the
friction reducer changes, the friction between the servicing fluid and the
conduit through which
the servicing fluid is flowing will also likely change. As such, because the
friction between the
flowing servicing fluid and the conduit through which the servicing fluid
flows changes, the
pressure due to friction between the flowing servicing fluid and the innermost
surface of the
conduit, referred to herein as "pipe friction pressure," may vary.
[0003] During a servicing operation, various factors contribute to the total
pressure
experienced within the conduit through which the servicing fluid is
communicated; the pipe
friction pressure is one such component. Therefore, changes in the pipe
friction pressure may
yield a change in the total pressure. Conventionally, there has been no means
by which to
assess whether a change in the total pressure is due to a change in the
effectiveness of the
friction reducer employed (resulting in a change in the pipe friction
pressure) or to some other
component of the total pressure. In many situations, it is desirable to know
whether changes in
the total pressure are the result of a change in the effectiveness of the
friction reducer or some
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other factor. As such, there exists a need for methods, systems, and
apparatuses for determining
the effectiveness of a friction reducer in subterranean formation servicing
operations.
SUMMARY
[0004] According to one aspect of the invention there is provided a method of
servicing a
subterranean formation comprising communicating a servicing fluid comprising a
hydratable
friction reducer and a base fluid to the subterranean formation via a route of
fluid
communication, determining an actual percent by which the friction reducer
reduces a pipe
friction pressure, comparing the actual percent by which the friction reducer
reduces the pipe
friction pressure to an ideal percent by which the friction reducer should
reduce pipe friction
pressure to determine an effectiveness of the friction reducer, and
determining if the
effectiveness of the friction reducer is within an acceptable range.
[0005] In an embodiment, the method further comprises determining the ideal
percent by which
the friction reducer should reduce pipe friction pressure.
[0006] In an embodiment, the ideal percent by which the friction reducer
should reduce pipe
friction comprises a previously determined value.
[0007] In an embodiment, determining the actual percent by which the friction
reducer reduces
the pipe friction comprises: diverting at least a portion of the servicing
fluid from the route of
fluid communication through a friction reducer meter; measuring a pressure at
a first point
within the friction reducer meter and a pressure at a second point within the
friction reducer
meter; and calculating the difference between the pressure at the first point
and the pressure at
the second point. The flow of the portion of the servicing fluid diverted
through the friction
reducer meter may comprise a turbulent fluid flow.
[0008] In an embodiment, the determination of the effectiveness of the
friction reducer is
determined at the instant of measuring the pressure at the first point within
the friction reducer
meter and the pressure at the second point within the friction reducer.
[0009] In an embodiment, the method further comprises adjusting the
composition of the
servicing fluid, the route of fluid communication, or both in response to the
effectiveness of the
friction reducer where the effectiveness of the friction reducer is not within
the desirable range.
Adjusting the composition of the servicing fluid may comprise altering the
amount of friction
reducer, altering the type of friction reducer, adding second friction
reducer, adding a
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component to the base fluid, subtracting a component from the base fluid,
altering the
composition of the base fluid, or combinations thereof. Adjusting the route of
fluid
communication may comprise altering the amount of time for hydration of the
friction reducer,
altering the amount of time prior to communicating the servicing fluid to the
subterranean
formation, altering the amount of time the servicing fluid is mixed, altering
the pressure at
which the servicing fluid is communicated to the subterranean formation,
altering the volume of
servicing fluid communicated to the subterranean formation, or combinations
thereof.
[0010] In an embodiment, adjusting the servicing fluid increases the hydration
of the friction
reducer.
[0011] In an embodiment, adjusting the servicing fluid increases the
effectiveness of the
friction reducer.
[0012] In an embodiment, the route of fluid communication comprises one or
more storage
vessels, one or more supply lines, a blending pump, a low-pressure-side
conduit, one or more
pressurizing pumps, a manifold, a high-pressure-side conduit, a wellhead, the
pipe string, one or
more pathways between the pipe string and the subterranean formation, or
combinations
thereof.
[0013] In an embodiment, the base fluid comprises an aqueous base fluid.
[0014] In an embodiment, the aqueous base fluid comprises water produced from
the
subterranean formation.
[0015] In an embodiment, the servicing fluid comprises a fracturing fluid. The
fracturing fluid
may comprise a proppant.
[0016] In an embodiment, the servicing fluid comprises a perforating fluid, a
hydrajetting fluid,
or combinations thereof
[0017] In an embodiment, the friction reducer comprises a polyacrylamide, a
copolymer of
polyacrylamide and acrylic acid, a copolymer of polyacrylamide and 2-
acrylamido-2-
methylpropane sulfonic acid (AMPS), or combinations thereof
[0018] In an embodiment, the servicing fluid further comprises a proppant, an
acid, an abrasive,
a scale inhibitor, a rheology modifying agent, a resin, a viscosifying agent,
a suspending agent,
a dispersing agent, a salt, an accelerant, a surfactant, a retardant, a
defoamer, a settling
prevention agent, a weighting material, a vitrified shale, a formation
conditioning agent, a pH-
adjusting agent, or combinations thereof.
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[0019] According to another aspect of the invention there is provided a method
of servicing
a subterranean formation comprising communicating a servicing fluid comprising
a hydratable
friction reducer and a base fluid to the subterranean formation via a route of
fluid
communication, measuring a wellhead pressure, determining a pipe friction
pressure
independent from the wellhead pressure, calculating a formation response
pressure, and
monitoring the formation response pressure.
[0020] In an embodiment, determining the pipe friction pressure comprises:
diverting at least a
portion of the servicing fluid from the route of fluid communication through a
friction reducer
meter; measuring a pressure at a first point within the friction reducer meter
and a pressure at a
second point within the friction reducer meter; and calculating the difference
between the
pressure at the first point and the pressure at the second point. The flow of
the portion of the
servicing fluid diverted through the friction reducer meter may comprise a
turbulent fluid flow.
[0021] In an embodiment, the method further comprises adjusting the
composition of the
servicing fluid, adjusting the route of fluid communication, or both in
response to the formation
response pressure. Adjusting the composition of the servicing fluid may
comprise altering the
amount of friction reducer, altering the type of friction reducer, adding
second friction reducer,
adding a component to the base fluid, subtracting a component from the base
fluid, altering the
composition of the base fluid, altering the type of servicing fluid
communicated, or
combinations thereof. Adjusting the route of fluid communication may comprise
altering the
amount of time prior for hydration of the friction reducer, altering the
amount of time prior to
communicating the servicing fluid to the subterranean formation, altering the
amount of time
the servicing fluid is mixed, altering the pressure at which the servicing
fluid is communicated
to the subterranean formation, altering the volume of servicing fluid
communicated to the
subterranean formation, or combinations thereof.
[0022] In an embodiment, adjusting the communication of the servicing fluid
comprises
altering the pressure at which fluid is communicated, altering the rate at
which fluid is
communicated, or combinations thereof.
[0023] In an embodiment, the servicing fluid comprises a fracturing fluid, a
perforating fluid, a
hydrajetting fluid, or combinations thereof.
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[0024] In an embodiment, the servicing fluid further comprises a proppant, an
acid, an abrasive,
a scale inhibitor, a rheology modifying agent, a resin, a viscosifying agent,
a suspending agent,
a dispersing agent, a salt, an accelerant, a surfactant, a retardant, a
defoamer, a settling
prevention agent, a weighting material, a vitrified shale, a formation
conditioning agent, a pH-
adjusting agent, or combinations thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 is a partial cutaway view of the operating environment of the
invention
depicting a wellbore penetrating a subterranean formation.
[0026] Figure 2 is a partial cutaway view of an embodiment of friction reducer
effectiveness meter.
[0027] Figure 3 is a schematic overview of a method of servicing a
subterranean formation.
[0028] Figure 4 is a graph depicting the percent friction reduction over time
for various
servicing fluids.
DETAILED DESCRIPTION
[0029] Unless otherwise specified, use of the terms "connect," "engage,"
"couple,"
"attach," or any other like term describing an interaction between elements is
not meant to limit
the interaction to direct interaction between the elements and may also
include indirect
interaction between the elements described.
[0030] Unless otherwise specified, use of the terms "up," "upper," "upward,"
"uphole,"
"upstream," or other like terms shall be construed as generally from the
formation toward the
surface or toward the surface of a body of water; likewise, use of "down,"
"lower,"
"downward," "downhole," "downstream," or other like terms shall be construed
as generally
into the formation away from the surface or away from the surface of a body of
water,
regardless of the wellbore orientation. Use of any one or more of the
foregoing terms shall not
be construed as denoting positions along a perfectly vertical axis.
[0031] Unless otherwise specified, use of the term "subterranean formation"
shall be
construed as encompassing both areas below exposed earth and areas below earth
covered by
water such as ocean or fresh water.
[0032] Referring to Figure 1, an embodiment of an operating environment for a
Friction
Reducer Effectiveness (FRE) meter and a method of using the same is
illustrated. It is noted
that although some of the figures may exemplify horizontal or vertical
wellbores, the principles
of the devices, systems, and methods disclosed may be similarly applicable to
horizontal
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wellbore configurations, conventional vertical wellbore configurations, and
combinations
thereof. Therefore, the horizontal or vertical nature of any figure is not to
be construed as
limiting the wellbore to any particular configuration.
[0033] As depicted in Figure 1, the operating environment generally comprises
a wellbore
114 that penetrates a subterranean formation 102 for the purpose of recovering
hydrocarbons,
storing hydrocarbons, disposing of carbon dioxide, or the like. The wellbore
114 may be drilled
into the subterranean formation 102 using any suitable drilling technique. In
an embodiment, a
drilling or servicing rig comprises a derrick with a rig floor through which a
pipe string 150
(e.g., a drill string, segmented tubing, coiled tubing, etc.) may be
positioned within or partially
within the wellbore 114. A wellbore servicing apparatus 140 configured for one
or more
wellbore servicing operations may be integrated within the pipe string 150.
Additional
downhole tools may be included with or integrated within the wellbore
servicing apparatus
and/or the pipe string 150 for example, one or more isolation devices, for
example, packers such
as swellable packers or mechanical packers.
[0034] The drilling or servicing rig may be conventional and may comprise a
motor driven
winch and other associated equipment for lowering the pipe string 150 into the
wellbore 114.
Alternatively, a mobile workover rig, a wellbore servicing unit (e.g., coiled
tubing units), or the
like may be used to lower the pipe string 150 into the wellbore 114.
[0035] The wellbore 114 may extend substantially vertically away from the
earth's surface
over a vertical wellbore portion, or may deviate at any angle from the earth's
surface 104 over a
deviated or horizontal wellbore portion. In alternative operating
environments, portions or
substantially all of the wellbore 114 may be vertical, deviated, horizontal,
and/or curved. In
some instances, a portion of the pipe string 150 may be secured into position
within the
wellbore 114 in a conventional manner using cement 116; alternatively, the
pipe string 150 may
be may be partially cemented in wellbore 114; alternatively, the pipe string
150 may be
uncemented in the wellbore 114. In an embodiment, the pipe string 150 may
comprise two or
more concentrically positioned strings of pipe (e.g., a first pipe string may
be positioned within
a second pipe string). It is noted that although some of the figures may
exemplify a given
operating environment, the principles of the devices, systems, and methods
disclosed may be
similarly applicable in other operational environments, such as offshore
and/or subsea wellbore
applications.
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[0036] The devices, methods, and systems disclosed herein generally relate to
an FRE
meter. In an embodiment, the FRE meter may be employed to independently
determine one or
more components of the total pressure during a subterranean formation
servicing operation. In
an embodiment, independently determining one or more components of the
servicing fluid may
allow adjustment of the servicing operation to achieve a desired result.
[0037] Referring again to Figure 1, an embodiment of a route of fluid
communication to the
subterranean formation 102, illustrated by flow arrows 10, is shown in the
context of a wellbore
servicing equipment spread or layout (e.g., a fracturing spread) assembled at
a well site. In the
embodiment of Figure 1, the route of fluid communication 10 may generally
comprise one or
more storage vessels 230, one or more supply lines 220, a blending pump 210, a
low-pressure-
side conduit 200, one or more pressurizing pumps 190, a high-pressure manifold
180, a high-
pressure-side conduit 170, a wellhead 160, the pipe string 150, and,
optionally, one or more
pathways between the pipe string 150 and the formation 102. Although Figure 1
illustrates a
general route of fluid communication to the subterranean formation 102, the
FRE meter
disclosed herein may be applicable to other suitable routes of fluid
communication. For
example, a route of fluid communication, like the route of fluid communication
illustrated in
Figure 1, may further comprise various other fluid conduits, such as, one or
more conduits
leading to the manifold.
[0038] In an embodiment, the one or more storage vessels 230 may comprise any
suitable
storage device, for example a tank, reservoir, hopper, container, or the like.
The storage vessels
230 may be portable or movable, alternatively, permanent or semi-permanent.
The storage
vessels 230 may be configured to store a given material or substance as will
be necessary for a
given servicing operation. In a non-limiting example, the storage vessels may
be individually
configured for the storage of a liquid, a solid, a semi-solid, a suspension, a
powder, a slurry, a
gas, or combinations thereof. In an embodiment, one or more components of the
servicing fluid
may be stored in the one or more storage vessels. For example, a first storage
vessel 230 may
store a first servicing fluid component (e.g., a base fluid, as will be
discussed herein below), a
second storage vessel 230 may store a second servicing fluid component (e.g.,
a friction
reducer, as will be discussed herein below), and a third, fourth, fifth,
etcetera, storage vessel 230
may store one or more additional servicing fluid components.
[0039] In an embodiment, the one or more storage vessels 230 may be connected
to one or
more supply lines. The supply lines 220 may comprise any suitable conduit,
nonlimiting
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examples of which include a pipe, a line, a tubing member, or the like. The
supply lines may
comprise flowbore extending therethrough. In an embodiment, the one or more
supply lines
220 may comprise a route of fluid communication between the storage vessels
230 and the
blending pump 210. In an alternative embodiment, one or more of the storage
vessels 230 may
be directly connected to the blending pump 210.
[0040] In an embodiment, the one or more supply lines 220 may be connected to
the
blending pump 210. The blending pump 210 may comprise any suitable
configuration. The
blending pump 210 may be configured to blend servicing fluid components
introduced therein
and to discharge the resulting composition therefrom. The blending pump 210
may comprise a
route of fluid communication between the one or more supply lines 220 and the
low-pressure-
side conduit 200.
[0041] In an embodiment, the blending pump 210 may be connected to a low-
pressure-side
conduit 200. The low-pressure-side conduit 210 may comprise any suitable
conduit,
nonlimiting examples of which include a pipe, a line, a tubing member, or the
like. The low-
pressure-side conduit 200 may comprise a flowbore extending therethrough. The
low-pressure-
side conduit may comprise a route of fluid communication between the blending
pump 210 and
the one or more pressurizing pumps 190.
[0042] In an embodiment, the low-pressure-side conduit 200 may be connected
with the
one or more pressurizing pumps 190. The pressurizing pumps 190 may be
configured to
increase the pressure of a fluid moving therethrough. Although Figure 1
illustrates three
independent pressurizing pumps, any suitable number of pumps may be employed.
The
pressurizing pumps may comprise any suitable type or configuration of pump.
Nonlimiting
examples of a suitable pump include a centrifugal pump, a gear pump, a screw
pump, a roller
pump, a scroll pump, a piston pump, a progressive cavity pump, or combinations
thereof. The
one or more pressurizing pumps 190 may comprise a route of fluid communication
between the
low-pressure-side conduit 200 and the manifold 180.
[0043] In an embodiment, the one or more pressurizing pumps 190 may be
connected with
the manifold 180. The manifold 180 may suitably comprise one or more pipes,
lines, valves,
connections, the like, or combinations thereof. In an embodiment, the manifold
180 may be
configured to merge two or more fluid streams (e.g., from the one or more
pressurizing pumps
190) into a single fluid stream. The manifold 180 may comprise a flowbore
comprising a route
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of fluid communication between the pressurizing pumps 190 and the high-
pressure-side conduit
170.
[0044] In an embodiment, the manifold 180 may be connected with the high-
pressure-side
conduit 170. The high-pressure-side conduit 170 may comprise any suitable
conduit,
nonlimiting examples of which include a pipe, a line, a tubing member, or the
like. The high-
pressure-side conduit 170 may comprise an axial flowbore extending
therethrough. The high-
pressure-side conduit 170 may comprise a route of fluid communication between
the manifold
180 and the wellhead 160.
[0045] In an embodiment, the high-pressure-side conduit 170 may be connected
with the
wellhead 160. The wellhead may suitably comprise one or more pipes, lines,
valves,
connections, the like, or combinations thereof. The wellhead 160 may comprise
one or more
flowbores for the communication of a fluid therethrough. The wellhead 160 may
comprise a
route of fluid communication between the high-pressure-side conduit 170 and
the pipe string
150.
[0046] In an embodiment, the wellhead 160 may be connected to the pipe string
150. The
pipe string 150 may comprise a flowbore for the communication of fluid
therethrough. In
various embodiments, the pipe string 150 may comprise a casing string, a
liner, a production
tubing, coiled tubing, a drilling string, the like, or combinations thereof.
The pipe string 150
may extend from the earth's surface 104 downward within the wellbore 114 to a
predetermined
or desirable depth.
[0047] In an embodiment where the route of fluid communication 10 comprises a
wellbore
servicing apparatus 140, the wellbore servicing apparatus 140 or some part
thereof may be
incorporated or integrated within the pipe string 150. The wellbore servicing
apparatus 140
may be configured to perform a given servicing operation, for example,
fracturing the formation
102, expanding or extending a fluid path through or into the subterranean
formation 102,
producing hydrocarbons from the formation 102, or other servicing operation.
In an
embodiment, the wellbore servicing apparatus 140 may comprise one or more
ports, apertures,
nozzles, jets, windows, or combinations thereof for the communication of fluid
from the
flowbore of the pipe string 150 to the subterranean formation 102. In an
embodiment, the
wellbore servicing apparatus comprises a housing comprising a plurality of
housing ports, a
sleeve being movable with respect to the housing, the sleeve comprising a
plurality of sleeve
ports, the plurality of housing ports being selectively alignable with the
plurality of sleeve ports
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to provide a fluid flow path from the wellbore servicing apparatus to the
wellbore, the
subterranean formation, or combinations thereof. Such a wellbore servicing
apparatus is
described in greater detail in U.S. Application No. 12/274,193, which is
incorporated in its
entirety herein by reference.
[0048] Persons of ordinary skill in the art with the aid of this disclosure
will appreciate that
the components of route of fluid communication 10 described herein may be
connected and/or
coupled via any suitable connection. Nonlimiting examples of suitable
connections may
include flanges, collars, welds, or combinations thereof. One of more of the
components of
route of fluid communication 10 may include various configurations of pipe
tees, elbows, the
like, or combinations thereof.
[0049] In an embodiment the FRE meter generally comprises a route of fluid
communication of a servicing fluid, a side-stream from the route of fluid
communication, a flow
meter disposed in the side-stream, two or more pressure gauges, optionally, a
flow regulator,
and, optionally, a side-stream valve. The side-stream may be configured such
that a portion of
the servicing fluid flows may be diverted from the route of fluid
communication through the
side-stream.
[0050] Referring to Figure 2, an embodiment of an FRE meter 300 is
illustrated. In the
embodiment of Figure 2, the FRE meter comprises a side-stream 310, a first
pressure gauge
320a, a second pressure gauge 320b, a flow-rate meter 330, one or more
optional side-stream
valves 350, and an optional flow regulator 340.
[0051] In an embodiment, the FRE meter 300 may be connected to one or more
suitable
components of a route of fluid communication such as route of fluid
communication 10. In the
embodiment of Figure 2, the FRE meter 300 is connected to and in fluid
communication with
the low-pressure-side conduit 200. In alternative embodiments, one of skill in
the art viewing
the instant disclosure will recognize that the FRE meter 300 might be
connected to the storage
vessels 230, to the supply lines 220, the blending pump 210, the low-pressure-
side conduit 200,
the one or more pressurizing pumps 190, the manifold 180, the high-pressure-
side conduit 170,
the wellhead 160, the pipe sting 150, or combinations thereof.
[0052] In an embodiment, the side-stream 310 comprises any suitable conduit
through
which at least a portion of the servicing fluid may be routed. Nonlimiting
examples of such a
conduit include a pipe, tube, the like, or combinations thereof. The side-
stream 310 may
comprise a flowbore extending therethrough and may be in fluid communication
with the route
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of fluid communication 10. In the embodiment of Figures 1 and 2, the side-
stream 310 is
connected to the low-pressure-side conduit 200 and is in fluid communication
therewith such
that a portion of the fluid flowing via route of fluid communication 10 may be
selectively
diverted through the side-stream 310.
[0053] The side-stream 310 may be of any suitable length and any suitable
diameter. In an
embodiment, the side-stream 310 comprises a conduit of a suitable, known
diameter. In an
embodiment, the diameter may be within the range of from about 0.25 inches to
about 12
inches, alternatively, from about 0.5 inches to about 4 inches, alternatively,
about 0.5 inches. In
an embodiment, the length of the side-stream 310 may be within the range of
from about 1 foot
to about 25 feet, alternatively, from about 1.5 feet to about 20 feet,
alternatively, from about 2
feet to about 10 feet. The side-stream 310 may be characterized as straight,
curved, looped, or
combinations thereof and may comprise one or more elbows, bends, joints, the
like, or
combinations thereof.
[0054] In an embodiment, the side-stream 310 conduit comprises a suitable
inner surface.
In an embodiment, the inner surface of the side-stream 310 may comprise a
suitable roughness,
as will be appreciated by one of skill in the art. For example, in an
embodiment the relative
roughness with respect to the pipe diameter may be in the range of from about
0 to about 0.05,
alternatively, from about 0 to about 0.001.
[0055] In the embodiment of Figure 2, the FRE meter 300 comprises a flow-rate
meter 330.
In an embodiment, the flow-rate meter 330 is configured to determine the rate
at which a fluid is
moving through the flowbore of the side-stream 310. The flow-rate meter 330
may comprise
any type or configuration of device or apparatus suitable for measuring or
determining a rate
fluid of flow. Nonlimiting examples of a suitable types or configurations of a
flow-rate meters
include Coriolis mass flow meters, differential pressure flow meters,
electromagnetic flow
meters, positive displacement flow meters, ultrasonic flow meters, turbine or
paddlewheel flow
meters, variable area flowmeters, the like, or combinations thereof.
[0056] In the embodiment of Figure 2, the FRE meter 300 comprises a first
pressure gauge
320a and a second pressure gauge 320b. In an embodiment, the first pressure
gauge 320a, the
second pressure gauge 320b, or both is configured to measure the pressure of
the fluid at a point
within the side-stream 310. The first and second pressure gauges, 320a and
320b, may
comprise any suitable type or configuration of pressure gauge for determining
or monitoring the
pressure of fluid. Non-limiting examples of a suitable pressure gauge include
a hydrostatic
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gauge, a piston-type gauge, a liquid column gauge, a mechanical gauge, a
diaphragm gauge, a
piezoresistive strain gauge, a capacitive gauge, a magnetic gauge, a
piezoelectric gauge, an
optical fiber gauge, a potentiometric gauge, a resonant gauge, or combinations
thereof. The first
pressure gauge 320a, the second pressure gauge 320b, or both may comprise a
suitable output,
for example, a display, an electric signal, a dial, etcetera.
[0057] In an embodiment, the first pressure gauge 320a and the second pressure
gauge 320b
may be separated by a known distance. In the embodiment of Figure 2, the first
pressure gauge
320a and the second pressure gauge 320b are illustrated as being separated by
distance d. In an
embodiment, distance d may be within the range of from about 1 foot to about
25 feet,
alternatively, from about 1.5 feet to about 20 feet, alternatively, from about
2 feet to about 10
feet.
[0058] In an embodiment where the FRE meter 300 comprises one or more side-
stream
valves 350, the side-stream valve 350 may comprise any suitable device or
apparatus
configured to selectively alter, adjust, allow, disallow, or combinations
thereof, flow of a fluid
therethrough. The side-stream valves 350 may be manually manipulatable,
automatically
manipulatable, or combinations thereof. Suitable valves are generally known to
one of skill in
the art.
[0059] In an embodiment where the FRE meter 300 comprises a flow regulator
340, the
flow regulator 340 may comprise any suitable device or apparatus configured to
impede, resist,
or prohibit fluid flow therethrough in a given direction, for example, a check-
valve. In an
embodiment, the flow regulator may additionally be configured to selectively
alter, adjust,
allow, disallow, or combinations thereof, flow of a fluid therethrough, for
example, a valve.
Suitable devices or apparatuses operable as the flow regulator 340 are
generally known to one
of skill in the art.
[0060] In an embodiment, the FRE meter 300 disclosed herein may be employed to
independently determine the pipe friction pressure, the formation response
pressure, or other
components of the wellhead pressure.
[0061] In an embodiment, during a wellbore servicing operation several
pressure
components may contribute to the total pressure which may be measured at the
wellhead,
referred to as the "wellhead pressure." For example, the wellhead pressure may
comprise a
formation response pressure component, a pipe friction pressure component, a
hydrostatic fluid
pressure component, and one or more additional pressure components such as
perforation
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friction. As used herein, "formation response pressure" refers to the
component of the
wellhead pressure attributable to the response of the subterranean formation
into which the
servicing fluid is introduced during a servicing operation. A near-wellbore
pressure component
and a formation friction pressure component may contribute to the formation
response pressure.
As used herein, "near-wellbore pressure" generally refers to pressure due to
flow restrictions
from the perforations to the fracture such as, for example, tortuosity. As
used herein "formation
friction pressure" generally refers to the pressure due to friction between a
servicing fluid and a
fracture as the servicing fluid moves through the fracture. As used herein,
"pipe friction
pressure" refers to the pressure due to pipe friction and "pipe friction"
refers to the friction
between the servicing fluid and the inner surface of the pipe string as the
servicing fluid flows
through the pipe string. As used herein, hydrostatic fluid pressure generally
refers to the
pressure at a given point within a fluid generally due to the weight of the
fluid above it.
[0062] In an embodiment, determining the pipe friction pressure independent
from one or
more other components of the wellhead pressure may allow the efficiency of the
friction
reducer included within the servicing fluid flowing via the route of fluid
communication 10 to
be ascertained or calculated. In an embodiment, knowledge of the efficiency of
the friction
reducer may allow an operator to adjust the servicing fluid to achieve a
desired level of friction
reducer efficiency.
[0063] In another embodiment, determining the formation response pressure
independent
from one or more other components of the wellhead pressure may provide an
operator with
valuable information regarding downhole conditions during the performance of
the servicing
operation. In an embodiment, knowledge of downhole conditions during the
servicing
operation may allow an operator to adjust the servicing operation parameters
to achieve one or
more desired results.
[0064] In an embodiment, the servicing fluid may comprise any suitable
servicing fluid.
Nonlimiting examples of suitable servicing fluids include a fracturing fluid,
a perforating fluid,
an acidizing fluid, a debris removal fluid, the like, or combinations thereof.
In an embodiment,
the servicing fluid may generally comprise a base fluid, a friction reducer,
and, optionally, one
or more additional components which may include but are not limited to
proppants, scale
inhibitors, biocides, surfactants, breakers, relative permeability modifiers,
or the like.
[0065] In an embodiment, the base fluid may comprise an aqueous base fluid,
alternatively,
a substantially aqueous base fluid. In an embodiment, a substantially aqueous
base fluid
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comprises less than about 50% of a nonaqueous component, alternatively less
than about 45%,
40%, 35%, 30%, 25%, 20%, 15%, 10%, 5%, 4%, 3%, 2% or 1% of a nonaqueous
component
by weight of the base fluid. In an embodiment, the base fluid may further
comprise an
inorganic monovalent salt, multivalent salt, or combinations thereof.
Nonlimiting examples of
salts suitable for use in such a base fluid include water soluble chloride,
bromide and carbonate,
hydroxide and formate salts of alkali and alkaline earth metals, zinc bromide,
and combinations
thereof. The salt or salts in the base fluid may be present in an amount
ranging from greater
than about 0% by weight of the base fluid to a saturated salt solution. The
water may be fresh
water or salt water. Examples of the base fluid include for are not limited to
water produced
from the subterranean formation, flowback water, water transported to the site
of the servicing
operation, or both.
[0066] In an embodiment, the base fluid may comprise a nonaqueous base fluid.
In an
embodiment, a nonaqueous base fluid may comprise an oleaginous fluid.
Nonlimiting
examples of such an oleaginous olefins, kerosene, diesel oil, fuel oil,
synthetic oils, linear or
branched paraffins, olefins, esters, acetals, mixtures comprising crude oil,
derivatives thereof, or
combinations thereof.
[0067] In an embodiment, the base fluid may comprise an emulsion of an aqueous
fluid and
a nonaqueous fluid. Nonlimiting examples of an emulsion include an invert
emulsion (a water-
in-oil emulsion), an oil-in-water emulsion, a reversible emulsion, or
combinations thereof
[0068] In an embodiment, the friction reducer may comprise any suitable
friction reducer.
In an embodiment the friction reducer comprises a hydratable friction reducer.
The hydratable
friction reducer may be effective to reduce friction between a servicing fluid
comprising the
friction reducer and a conduit through which the servicing fluid is
communicated. In an
embodiment, the hydratable friction reducer comprises a polymer. Nonlimiting
examples of a
suitable polymer include a polyacrylamide, polyacrylate, a copolymer of
polyacrylamide and
polyacrylate, a copolymer of polyacrylamide, and 2-acrylamido-2-methylpropane
sulfonic acid
(AMPS), polyethylene oxide, polypropylene oxide, a copolymer of polyethylene
and
polypropylene oxide, polysaccharides, and combinations thereof Other suitable
friction
reducers will be known to those of skill in the art. Examples of suitable
friction reducers that
are commercially available are FR-46, FR-56, FR-58, FR-66, FDP-S944-09, SGA-2,
SGA-5,
and SGA-18 from Halliburton Energy Services, Inc.
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[0069] In an embodiment, the one or additional components comprise any
suitable
servicing fluid components. Suitable servicing fluid components will be known
to those of skill
in the art with the aid of this disclosure. Nonlimiting examples of such
components include a
proppant, an acid, an abrasive, a scale inhibitor, a rheology modifying agent,
a resin, a
viscosifying agent, a suspending agent, a breaker, a dispersing agent, a salt,
an accelerant, a
surfactant, a relative permeability modifier, a retardant, a defoamer, a
settling prevention agent,
a weighting material, a vitrified shale, a formation conditioning agent, a pH-
adjusting agent, or
combinations thereof. These additional components may be included singularly
or in
combination.
[0070] In an embodiment, the base fluid, the friction reducer, and any
additional component
are blended together in any suitable order to form the wellbore servicing
fluid. In an
embodiment, the attributes of one or more of the components of the servicing
fluid may vary
from one servicing operation to another. Further, the components of a
servicing fluid or the
relative amounts thereof may vary throughout the course of a given servicing
operation. Not
intending to be bound by theory, the friction reducer employed in a servicing
fluid may vary in
compatibility with the other servicing fluid components between servicing
operations or
throughout a servicing operation, thereby causing the friction reducer to vary
as to its
effectiveness. For example, the base fluid may comprise water produced from
the subterranean
formation; because the attributes and/or relative amount of the produced water
may vary over
the course of the servicing operation, the friction reducer may vary in
compatibility with the
base fluid and, as such, the effectiveness of the friction reducer may vary.
Not intending to be
bound by theory, poor dispersion, inversion, hydration, or combinations
thereof of a friction
reducer may cause a friction reducer to exhibit less than a desired level of
effectiveness.
[0071] In an embodiment, it may be desirable for a friction reducer to be
about 100,
alternatively, 95, 90, 85, 80, 75, or 70% effective. In an embodiment, where a
friction reducer
exhibits less than the desired level of effectiveness, it may be desirable to
adjust the servicing
fluid, the route of fluid communication of the servicing fluid; or
combinations thereof to
improve dispersion, inversion, hydration, or combinations thereof and thereby
increase friction
reducer effectiveness.
[0072] Disclosed herein is an embodiment of a method of servicing a
subterranean
formation. In various embodiments, the servicing operation may comprise a
fracturing
operating, a perforating and/or hydrajetting operation, an acidizing
operation, or combinations
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thereof. In the embodiment of Figure 3, the servicing method 50 generally
comprises the steps
of determining an ideal percent friction reduction for a given friction
reducer 500,
communicating a subterranean formation servicing fluid to the subterranean
formation 510, and
determining an actual percent friction reduction 520. In an embodiment, the
subterranean
formation servicing method optionally comprises calculating a percent
effectiveness of the
friction reducer 530. In an embodiment, a servicing method optionally
comprises adjusting at
least one parameter of the servicing operation in response to the
effectiveness of the friction
reducer 540.
[0073] In an embodiment, determining the ideal percent friction reduction
500, %FRideab
may comprise any suitable method. As used herein, the term "ideal percent
friction reduction"
refers to the ideal percentage by which the pipe friction is reduced by a
friction reducer. The
%FR/dear may be determined analytically, experimentally, or combinations
thereof.
[0074] In an embodiment, determining the %FR/de& 500 may comprise an
experimental
determination. For a fluid flowing from a first point, Point A, to a second
point, Point B, in a
pipe, assuming that the diameter of the pipe remains constant, that the
elevation of the pipe
between Point A and Point B is unchanged, and that the velocity of the fluid
is constant along
the pipe, the pressure at Points A and B may be generally described in that
the pressure at Point
B, PB, is equal to the pressure at Point A, PA, minus the pipe friction
pressure, Pp,pe. Therefore,
assuming the foregoing, the pipe friction pressure will be equal to the
difference in the pressure
at Point A and the pressure at Point B as shown in equation (I):
Phpe = PA PB Equation (I).
[0075] In an embodiment, determining the %FRIdeal 500 may generally
comprise
determining the pipe friction pressure for a fluid (e.g., fresh water) that
does not comprise a
friction reducer, -Pinitiai, and determining the pipe friction pressure for
fresh water comprising a
friction reducer at its ideal effectiveness, P - Ideal. In an embodiment,
an experimental
determination of the %FRIdeal may also generally comprise comparing the P
Initial with the &eat-
[0076] In an embodiment, determining the P Imaal comprises observing the
difference in PA
and P B for fresh water from which a friction reducer is absent while flowing
through a conduit
(e.g., a pipe, a test loop, a pressure loop, or the like). In an embodiment,
determining the P - Ideal
comprises observing the difference in PA and P B for the same fresh water or a
substantially
similar fresh water with a friction reducer while flowing through the same or
a similar conduit.
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[0077] In an alternative embodiment, determining the hum,/ comprises
calculating the
change in pressure for a fluid (e.g., fresh water) from which a friction
reducer is absent at about
ambient conditions (e.g., about 25 C and about 1 atm. [101.325 kilopascal])
over a given
portion of a flow conduit of length L according to equation (II-A):
pV2 Lf
PInitial2g,D Equation (II-A) =
where p is the density of the fluid at about 25 C and about 1 atm. [101.325
kilopascal], V is the
velocity of the fluid, g, is the gravitational constant, D is the diameter of
the flow conduit, and
wherefis the friction factor. The friction factor, f, may be calculated
according to equation (III)
for a fully turbulent fluid flow:
¨2
f = {-- 2 log[el D 5.02 log e 1 D 14.5 Equation (III)
3.7 Re 3.7 Re
where e is the pipe roughness, D is the diameter of the flow conduit, and Re
is the Reynolds
number as calculated for the fluid at about 25 C and about 1 atm. [101.325
kilopascal]
(Shoehorn, M., Isr. Chem. Eng., 8, 7E (1976)).
[0078] As will be appreciated by one of skill in the art, one or more of the
time that the
friction reducer is in contact with an aqueous fluid, temperature of the
fluid, the solute (e.g., a
salt) concentration of the fluid, the combinations of solutes of the fluid,
the soluble and
insoluble organic materials of the fluid, the particulates of the fluid, the
pressure of the fluid, or
combinations thereof may vary the effectiveness of the friction reducer
utilized in such a fluid.
In an embodiment, the fluid for which the pipe friction will be determined
comprises
freshwater. Not intending to be bound by theory, utilizing freshwater to
determine the pipe
friction pressure may minimize the opportunity for incompatibility of the
friction reducer; as
such, the friction reducer may be fully or substantially hydrated (and
thereby, not intending to
be bound by theory, maximally effective). In an embodiment, the friction
reducer may be
contacted with the fluid for 20 seconds under appreciable flow or shear to
ensure the friction
reducer may be fully or substantially hydrated (and thereby, not intending to
be bound by
theory, maximally effective). In an embodiment, the maximum effectiveness of a
given
hydratable friction reducer may be determined where, for example, the friction
reducer has been
in contact with a fluid for a given amount of time, the fluid is at a given
temperature, the fluid is
at a given solute (e.g., a salt) concentration, the fluid is at a given
pressure, or combinations
thereof.
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[0079] In an embodiment, the presence of the friction reducer in the fluid
may reduce the
amount of pipe friction. Therefore, the Pmed may be less than the Pimtwd. By
comparing the
PIdeal and the Phutial, the percent by which the pipe friction is reduced, the
%Fitideai, may be
calculated according to equation (IV):
%FR/cf./ = 1( Pldeal x 100% Equation (IV).
Plinual
[0080] In an alternative embodiment, determining the %FR/ded 500 may
comprise an
analytical determination. Such an analytical determination of the %FR/dear may
generally
comprise calculating, deriving, or extrapolating %FRIdeal, Pldeal, Plninah or
combinations thereof
according to a suitable mathematical relationship.
[0081] In an embodiment, %FR/dear may be determined prior to the servicing
operation, at a
site removed from the servicing operation, or both. For example, %FRIdeal may
be determined
in a laboratory setting prior to a given servicing operation. In an
embodiment, where a %FR/deat
has been determined for a given friction reducer, the previously determined
%FR/dew may be
employed. For example, a %FRIdeal utilized in a prior or separate servicing
operation may be
employed as the %FR/de& for another servicing operation. It is specifically
contemplated that
the %FRAdea associated with a friction reducer may be known or may be derived
from other
known data and, as such, need not be determined for each and every servicing
operation.
[0082] In an embodiment, the servicing method 50 comprises communicating a
servicing
fluid comprising the friction reducer the subterranean formation 510. In an
embodiment, the
servicing fluid may be communicated to the subterranean formation 102 via a
suitable route of
fluid communication, for example, referring to Figure 1, route of fluid
communication 10.
[0083] In an embodiment, the components of the servicing fluid may be
provided from the
one or more storage vessels 230 to the blending pump 210 via the one or more
supply lines 220.
Alternatively, one or more of the components may be introduced directly into
the blending
pump 210. The servicing fluid components may be introduced at any suitable
rate, in any
suitable order, in any suitable ratio, as will be appreciated by one of skill
in the art. When
mixed, the servicing fluid may be routed from the blending pump 210 to the one
or more
pressurizing pumps 190 via the low-pressure-side conduit 200. A portion of the
servicing fluid
may be routed through each of the one or more pressurizing pumps 190, thereby
increasing the
pressure of the servicing fluid moving within the route of fluid communication
10. As will be
appreciated by one of skill in the art, the servicing fluid may be pressurized
to a suitable
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pressure, dependent upon the servicing operation being performed. The
pressurized servicing
fluid may be routed from the one or more pressurizing pumps 190 through the
manifold 180,
high-pressure-side conduit, wellhead 160, pipe string 150, and wellbore
servicing apparatus 140
to the subterranean formation 102. A portion of the servicing fluid may flow
into and/or
through the subterranean formation 102. Additionally, a portion of the
servicing fluid may be
circulated through the wellbore 114.
[0084] In an embodiment, the servicing method 50 may comprise determining the
actual
percent friction reduction, %FRActuat 520. In an embodiment, %FRAcivat may be
determined by
any suitable method. As used herein, the term "actual percent friction
reduction" refers to the
actual percentage by which the pipe friction of a servicing fluid is reduced
by a given friction
reducer.
[0085] In an embodiment, determining the %FRActuar 520 may comprise diverting
at least a
portion of the servicing fluid through the side-stream 310, measuring the
velocity of the
diverted servicing fluid, measuring a change in pressure of the diverted
servicing fluid over a
given distance, or combinations thereof.
[0086] In an embodiment, at least a portion of the servicing fluid flowing via
the route of
fluid communication may be diverted into the side-stream 310 of the FRE meter
300. In an
embodiment, the portion of the servicing fluid that is diverted may be in the
range of from about
less than 1% to about 99% of the total volume of servicing fluid,
alternatively, from about 1%
to about 20% of the total volume of servicing fluid, alternatively, from about
5% to about 15%
of the total volume of servicing fluid, alternatively, about 10% of the total
volume of servicing
fluid. In an embodiment, the percentage of the total volume of the servicing
fluid diverted into
the side-stream 310 may be adjusted by opening or closing the side-stream
valves 350.
[0087] In an embodiment, the average fluid velocity of the portion of the
servicing fluid
diverted into the side-stream 310 may be determined from the flow-rate meter
330. In an
embodiment, the average fluid velocity of the fluid flowing through the side-
stream may be any
suitable velocity. In an embodiment, the average fluid velocity of the fluid
flowing through the
side-stream may be in the range of from about 1 to about 200 feet per second
(fps),
alternatively, about 10 to about 100 fps, alternatively, about 20 to about 60
fps. In an
embodiment, the average fluid velocity of the fluid flowing through the side-
stream 310 may be
adjusted, for example, as by manipulation of one or more of the side-stream
valves 350. In an
embodiment, adjustment of one or more of the side-stream valves 350 may be
manual,
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automatic, or combinations thereof. For example, an operator viewing the
average fluid
velocity of the fluid within the side-stream 310 may manually adjust the side-
stream valve to
achieve a desirable average fluid velocity. Alternatively, the side-stream
valves 350 may be
automatically adjusted in response to the velocity of the fluid in the side-
stream 310 as
measured by the flow-rate meter (e.g., via a suitable connection between the
flow-rate meter
330 and the side-stream valves 350). In an embodiment, the velocity of the
fluid flowing via
the side-stream may be employed in comparing the ideal percent friction
reduction for the
friction reducer, %FRideai, to the actual friction reduction for that friction
reducer, %FRActuar=
For example, because %FR/decd may depend largely on fluid velocity and shear
rate, it may be
advantageous, alternatively, necessary, to know the fluid velocity at which
%FRActuar occurs to
ensure that %FRActua/ is compared to the appropriate %FRidecd, which is
discussed in greater
detail below.
[0088] In an embodiment, the flow of the servicing fluid through the side-
stream 310 may be
characterized as a turbulent flow. As will be appreciated by one of skill in
the art, turbulent
flow is a flow regime that may be characterized by secondary flows appreciable
in magnitude
compared to the primary flow direction, eddies, and apparent randomness.
Conversely, non-
turbulent flow may be referred to as laminar flow. The Reynolds number, a
dimensionless
number that relates the ratio of inertial forces to viscous forces, often
indicates whether a flow
regime will be characterized as turbulent or laminar for a given flow
geometry. Generally
Newtonian fluids flowing in pipes with circular cross-sections, flow regimes
where the
Reynolds number is greater than about 2000 may be characterized as turbulent
flow while flow
regimes where the Reynolds number is less than about 2000 may be characterized
as laminar
flow.
[0089] In an embodiment, the change in the pressure of the portion of the
servicing fluid
flowing over distance d within the FRE meter 300 is determined using the first
pressure gauge
320a and the second pressure gauge 320b. Not intending to be bound by theory,
as discussed
above, for a fluid flowing from a first point, Point A, to a second point,
Point B, in a pipe,
assuming that the diameter of the pipe remains constant, that the elevation of
the pipe between
Point A and Point B is unchanged, and that the velocity of the fluid is
constant along the pipe,
the pressure at Point A (e.g., as measured by the first pressure gauge 320a)
and the pressure at
Point B (e.g., as measured by the second pressure gauge 320b) may be generally
described in
that the pressure at Point B, PB, is equal to the pressure at Point A, PA,
minus the pipe friction
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pressure, Pp,pe. Therefore, assuming the foregoing, the pipe friction pressure
may be calculated
according to equation (I):
PPrpe = PA ¨ PB Equation (I).
[0090] In an embodiment, determining %FRActuar 520 may comprise
determining the pipe
friction pressure for the servicing fluid from which the friction reducer is
absent, Po;
determining the pipe friction pressure for the servicing fluid comprising a
friction reducer,
P Actual; and comparing the Po with the P Actual.
[0091] In an embodiment, determining the Po may comprise observing the
difference in PA
and P B for a servicing fluid from which a friction reducer is absent. In an
embodiment,
determining the P - Actual may comprise observing the difference in PA and P B
for a servicing fluid
comprising a friction reducer. By comparing the Po and the P41, the %FRActuar
may be
calculated according to equation (V):
%FR Actual 1 ?Act./ x 100% Equation (V).
P
[0092] In an alternative embodiment, the Po may be estimated,
calculated, or otherwise
determined based upon a prior known value, for example, based upon the value
of PInftw used in
determining %FR ideal as described above.
[0093] In another embodiment, Po may be calculated (similar to the
calculation of P - Inutal
given above) by equation (II-B):
pV2 Lf
P Equation (II-B)
2g,D
where L is the length of the flow conduit, p is the density of the fluid at 25
C and about 1 atm.
[101.325 kilopascal], V is the velocity of the fluid, g, is the gravitational
constant, D is the
diameter of the flow conduit, and where f is the fiction factor. The friction
factor, f, may be
calculated according to equation (III) for a fully turbulent fluid flow:
-2
Re 1 D 5.02 , ( 37 s/D 14.5
f = {¨ 2 log[ log ¨ Equation
(III)
3.7 . Re
where E is the pipe roughness, D is the diameter of the flow conduit, and Re
is the Reynolds
number as calculated for the fluid at about 25 C and about 1 atm. [101.325
kilopascal]
(Shacham, M., Isr. Chem. Eng., 8, 7E (1976)).
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[0094] In an embodiment, the servicing method 50 comprises calculating the
effectiveness
of the friction reducer 530. In an embodiment, calculating the effectiveness
of the friction
reducer 530 comprises comparing the ideal percent friction reduction for the
friction reducer,
9WRIdeal, to the actual friction reduction for that friction reducer,
%FRActuat. By comparing
%FRA/ and %FR Ideal, the effectiveness, expressed as a percent, may be
calculated according
to equation (VI):
Effectiveness =V0FR Actual .100% Equation (VI).
%FR Ideal
[0095] In an embodiment, the FRE meter 300 and the methods disclosed herein
may yield a
measure of friction reduction and/or friction reducer effectiveness at a time
from about 10 to
about 60 seconds after the friction reducer has been injected into the
servicing fluid (e.g., the
FU meter measures the pipe friction pressure at a point downstream from where
the
components of the servicing fluid are first mixed, as shown in Fig. 1). The
FRE meter 300 and
the methods disclosed herein may yield a measure of friction reduction and/or
friction reducer
effectiveness that is instantaneous and/or in real-time.
[0096] In an embodiment, the FRE Meter 300 allows for the determination of
the pipe
friction pressure independent from one or more other components of the
wellhead pressure. In
an embodiment where the pipe friction pressure is known, it may be possible to
calculate or
monitor changes in one or more other components of the wellhead pressure. For
example, it
may be possible to calculate the formation response pressure component, the
hydrostatic fluid
pressure component, or one or more additional pressure components independent
from the
wellhead pressure.
[0097] In an embodiment, the servicing method 50 further comprises adjusting
at least one
parameter of the servicing operation 540. In an embodiment, adjusting at least
one parameter of
a servicing operation 540 may increase the efficiency of a friction reducer,
effect a change in the
servicing operation, or combinations thereof.
[0098] As discussed above, a given friction reducer may vary as to its
effectiveness
dependent upon the servicing fluid in which it is used, and/or other
components present within
the servicing fluid. As such, it may be desirable to adjust one or more
parameters of the
servicing operation to achieve a desirable friction reducer effectiveness. In
an embodiment
where the effectiveness of a friction reducer is less than desired, an
operator may adjust one or
more parameters of the servicing operation to increase the effectiveness of
the friction reducer.
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[0099] As discussed above, the formation response pressure may indicate the
presence or
absence of a condition within a downhole portion of the wellbore and/or the
subterranean
formation. As such, it may be desirable to adjust one or more parameter of the
servicing
operation where the formation response pressure so-indicates.
[00100] In an embodiment adjusting one or more parameters of the servicing
operation may
comprise altering, changing, adjusting the composition of the servicing fluid,
for example, by
altering, changing, adjusting the base fluid of the servicing fluid, one or
more components of the
servicing fluid, the friction reducer used therein, or combinations thereof in
order to achieve a
desired effectiveness. For example, the operator might adjust or alter the
servicing fluid by
changing the amount or proportion of some component, adding a component,
altering a pH,
changing the amount, type, or proportion of friction reducer used, using a
different friction
reducer, using a combination of friction reducers, or combinations thereof
[00101] In an embodiment, adjusting at least one parameter of the servicing
operation may
comprise altering, changing, or adjusting the route of fluid communication of
the servicing fluid
in response to the effectiveness of the friction reducer. For example, the
operator might alter
the amount of time for hydration of the friction reducer, alter the amount of
time prior to
communicating the servicing fluid to the subterranean formation, alter the
amount of time the
servicing fluid is mixed, alter the pressure at which the servicing fluid is
communicated to the
subterranean formation, alter the volume of servicing fluid communicated to
the subterranean
formation, or combinations thereof.
[00102] In an embodiment, one or more of the steps of the servicing method
disclosed herein
may be implemented in software on one or more computers or other computerized
components
having a processor, user interface, microprocessor, memory, and other
associated hardware and
operating software. Software may be stored in tangible media and/or may be
resident in
memory on the computer. Likewise, input and/or output from the software, for
example ratios,
percentages, comparisons, and results may be stored in a tangible media,
computer memory,
hardcopy such a paper printout, or other storage device.
[00103] In an embodiment, data (e.g., pressures, pressure differentials, etc.)
obtained from
the performance of the foregoing methods may be input into a computer
automatically via a
suitable interface; alternatively, data may be input by a user or operator.
Calculations and
comparisons (e.g., percent effectiveness, ideal percent friction reduction,
actual percent friction
reduction) may be performed by a suitable computer or computerized component;
alternatively,
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calculations and comparisons may be performed by a user or operation. A
suitable computer or
computerized component may effect changes to the servicing operation (e.g.,
changes to the
servicing fluid, the route of fluid communication, or both) responsive to a
calculation,
comparison, or both (e.g., a comparison of the actual effectiveness of a
friction reducer with the
desired effectiveness of the friction reducer) via a suitable interface (e.g.,
electric, electronic,
mechanical, or combinations thereof); alternatively, the results of a
calculation or comparison
may be provided to a user or operator via a suitable display (e.g., a print-
out, a screen, etc) and
the user or operator may decide whether changes to the servicing operation are
desirable and, if
so effect one or more changes to the servicing operation via one or more
suitable control means
(a dial, switch, level, etc).
[00104] In an embodiment, the devices, systems, and/or methods of the instant
disclosure
may be employed to introduce a fracture into a subterranean formation (e.g., a
fracturing
operation). Hydrocarbon-producing wells often may be stimulated by hydraulic
fracturing
operations. In an embodiment of a fracturing operation, a fracturing fluid,
such as a particle
laden fluid, is pumped at relatively high-pressure into a wellbore. The
fracturing fluid may be
introduced into a portion of a subterranean formation at a sufficient pressure
and/or velocity
and/or initiate, create, extend, or enhance at least one fracture therein.
Proppants, such as grains
of sand, may be mixed with the fracturing fluid to keep the fractures open so
that hydrocarbons
may be produced from the subterranean formation and flow into the wellbore.
Hydraulic
fracturing may desirably create high-conductivity fluid communication between
the wellbore
and the subterranean formation.
[00105] In an embodiment, the method of introducing a fracture into a
subterranean
formation comprises preparing a fracturing fluid. In such an embodiment, the
servicing fluid
comprises a fracturing fluid comprising a base fluid, a proppant, a hydratable
friction reducer,
and, optionally, additives.
[00106] In an embodiment, the base fluid may comprise water. The water may be
potable,
non-potable, untreated, partially treated, treated water, or combinations
thereof. In an
embodiment, the water may be produced water that has been extracted from the
wellbore while
producing hydrocarbons form the wellbore. The produced water may comprise
dissolved
and/or entrained organic materials, salts, minerals, paraffins, aromatics,
resins, asphaltenes,
and/or other natural or synthetic constituents that are displaced from a
hydrocarbon formation
during the production of the hydrocarbons. In an embodiment, the water may be
flowback
WO 2012/010853 CA 02805703 2013-01-16PCT/GB2011/001112
25
water that has previously been introduced into the wellbore during wellbore
servicing operation.
The flowback water may comprise some hydrocarbons, gelling agents, friction
reducers,
surfactants and/or remnants of wellbore servicing fluids previously introduced
into the wellbore
during wellbore servicing operations. The water may further comprise local
surface water
contained in natural and/or manmade water features (such as ditches, ponds,
rivers, lakes,
oceans, etc.). Still further, the water may comprise water stored in local or
remote containers.
The water may be water that originated from near the wellbore and/or may be
water that has
been transported to an area near the wellbore from any distance. In some
embodiments, the
water may comprise any combination of produced water, flowback water, local
surface water,
and/or container stored water.
[00107] In an embodiment, proppant, the base fluid, the hydratable friction
reducer, and,
optionally, the additives are fed into the blending pump 210 via supply lines
220. The blending
pump 210 mixes solid and fluid components to achieve a well-blended fracturing
fluid. The
mixing conditions of the blending pump 210, including time period, agitation
method, pressure,
and temperature, may be chosen by one of ordinary skill in the art with the
aid of this disclosure
to produce a homogeneous blend having a desirable composition, density, and
viscosity. In
alternative embodiments, however, sand or proppant, water, friction reducer,
and/or additives
may be premixed and/or stored in a storage tank.
[00108] In an embodiment, the method of introducing a fracture into a
subterranean
formation comprises determining the ideal percent friction reduction, %FRideab
for a given
friction reducer. As disclosed above, the %FRidea/ may be determined by
experimental means.
For example, it may be determined that a given friction reducer ideally may
reduce pipe friction
by about up to 80% (%FR/dear = 80%) at about 15-25 seconds after injection of
the friction
reducer into the base fluid.
[00109] In an embodiment, the method of introducing a fracture into a
subterranean
formation comprises communicating the fracturing fluid to a subterranean
formation via a
suitable route of fluid communication, for example, route of fluid
communication 10 disclosed
herein. In an embodiment, the pressurizing pumps 190 may pressurize the
fracturing fluid to a
pressure suitable for delivery into the wellhead 160. For example, the
pressurizing pumps 190
may increase the pressure of the fracturing fluid to a pressure of up to about
20,000 psi or
higher. In an embodiment, the fracturing fluid may be combined to achieve a
total fluid flow
CA 02805703 2013-01-16
WO 2012/010853 PCT/GB2011/001112
26
rate that enters the wellhead 160 at a total flow of between about 1 BPM to
about 200 BPM,
alternatively from between about 50 BPM to about 150 BPM, alternatively about
100 BPM.
[00110] During the communication of the fracturing fluid, a portion of the
fracturing fluid
may be diverted from the route of fluid communication through an FRE meter so
as to
determine the actual percent friction reduction, %FRActual. In an embodiment,
to determine
%FRActõ,,/, the pipe friction pressure for the servicing fluid from which the
friction reducer is
absent, Po, may be calculated by equation (II-B):
pi/2 Lf
= 2g, D Equation (II-B)
where L is the length of the flow conduit, p is the density of the fluid at 25
C and about 1 atm.
[101.325 kilopascal], V is the velocity of the fluid, ge is the gravitational
constant, D is the
diameter of the flow conduit, and where f is the fiction factor. The friction
factor, f, may be
calculated according to equation (III) for a fully turbulent fluid flow:
-2
elD 5.0210g elD 14.5
J ={¨ 2 log[ Equation (III)
3.7 Re 3.7 Re
where e is the pipe roughness, D is the diameter of the flow conduit, and Re
is the Reynolds
number as calculated for the fluid at about 25 C and about 1 atm. [101.325
lcilopascal]
(Shacham, M., Isr. Chem. Eng., 8, 7E (1976)). P Actual may be determined by
measuring the pipe
pressure of the servicing fluid having the friction reducer present as the
servicing fluid flows via
the FRE meter. Therefore, as disclosed above, comparing Po with PActuat yields
the actual
percent by which the friction reducer reduces pipe friction. For example, it
may be determined
that a given friction reducer actually reduces pipe friction by 60% (%FRActual
= 60%) at about
15-25 seconds after injection into the fracturing fluid. As disclosed above,
comparing the
%FR/dear with the %FRActua yields the percent effectiveness. For example, a
friction reducer
that ideally reduces pipe friction by 80% and actually reduces pipe friction
by 60% would be
75% effective.
[00111] In an embodiment where the percent effectiveness of the friction
reducer is less than
a desired percent effectiveness, an operator may choose to adjust the
composition of the
servicing fluid, the route of fluid communication or both. For example, if an
operator desired
90% effectiveness, where a friction reducer performed at 75% effectiveness,
the operator might
choose to adjust the composition of the servicing fluid, the route of fluid
communication, or
combinations thereof. In an embodiment, adjusting the composition of the
servicing fluid, the
WO 2012/010853 CA 02805703 2013-01-16 PCT/GB2011/001112
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route of fluid communication, or combinations thereof may increase the
effectiveness of the
friction reducer by, not intending to be bound by theory, increasing the
hydration, inversion,
dispersion, or combinations thereof of the friction reducer.
[00112] In an embodiment, the operator may adjust the composition of the
servicing fluid by
altering the amount of friction reducer, altering the type of friction
reducer, adding second
friction reducer, adding a component to the base fluid, subtracting a
component from the base
fluid, altering the composition of the base fluid, or combinations thereof. In
an embodiment,
the operator may adjust the route of fluid communication by altering the
amount of time for
hydration of the friction reducer, altering the amount of time prior to
communicating the
servicing fluid to the subterranean formation, altering the amount of time the
servicing fluid is
mixed, altering the pressure at which the servicing fluid is communicated to
the subterranean
formation, altering the volume of servicing fluid communicated to the
subterranean formation,
or combinations thereof.
EXAMPLES
[00113] The embodiments having been generally described, the following
examples are
given as embodiments of the disclosure and to demonstrate the practice and
advantages thereof.
It is to be understood that the examples are presented herein as a means of
illustration and are
not intended to limit the specification or the claims.
[00114] In each of the following examples, an FRE meter, for example, similar
to FRE meter
300 disclosed herein, was used, for example, as by the methods disclosed
herein, to measure
friction reduction and/or the effectiveness of a friction reducer. The results
of these examples
are shown in Figure 4.
Example 1
[00115] 1 gpt (gallons per thousand gallons) [3.785 litres per 3785 litres] of
FR-56 was
injected into Duncan tap water flowing at a nominal rate of 28 gallons [106
litres] per minute
through a 0.56-inch [1.42 cm], smooth pipe. Approximately 20 seconds after the
friction
reducer was injected, the instantaneous friction reduction was measured at
about 72%, and the
friction reduction effectiveness was 100%. In an embodiment, this may
represent %FR Ideal.
Example 2
[00116] 1 gpt [3.785 litres per 3785 litres] of FR-56 was injected into Duncan
tap water
containing 16 wt% CaC1 (calcium chloride) flowing at a nominal rate of 28
gallons [106 litres]
per minute through a 0.56-inch [1.42 cm], smooth pipe. Approximately 20
seconds after the
WO 2012/010853 CA 02805703 2013-01-16 PCT/GB2011/001112
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friction reducer was injected, the instantaneous friction reduction was
measured at about 30%,
and the friction reduction effectiveness was 42%.
Example 3
[00117] 1 gpt [3.785 litres per 3785 litres] of FR-46 was injected into
untreated Velma field
water flowing at a nominal rate of 10 gallons [37.85 litres] per minute
through a 0.56-inch [1.42
cm], smooth pipe. Approximately 20 seconds after the friction reducer was
injected, the
instantaneous friction reduction was measured at about 48%, and the friction
reduction
effectiveness was 67%.
[00118] At least one embodiment is disclosed and variations, combinations,
and/or
modifications of the embodiment(s) and/or features of the embodiment(s) made
by a person
having ordinary skill in the art are within the scope of the disclosure.
Alternative embodiments
that result from combining, integrating, and/or omitting features of the
embodiment(s) are also
within the scope of the disclosure. Where numerical ranges or limitations are
expressly stated,
such express ranges or limitations should be understood to include iterative
ranges or limitations
of like magnitude falling within the expressly stated ranges or limitations
(e.g., from about 1 to
about 10 includes, 2, 3, 4, etc.; greater than 0.10 includes 0.11, 0.12, 0.13,
etc.). For example,
whenever a numerical range with a lower limit, RI, and an upper limit, Ru, is
disclosed, any
number falling within the range is specifically disclosed. In particular, the
following numbers
within the range are specifically disclosed: R=R1 +k* (Ru-R1), wherein k is a
variable ranging
from 1 percent to 100 percent with a 1 percent increment, i.e., k is 1
percent, 2 percent, 3
percent, 4 percent, 5 percent, ..... 50 percent, 51 percent, 52 percent, ...,
95 percent, 96 percent,
97 percent, 98 percent, 99 percent, or 100 percent. Moreover, any numerical
range defined by
two R numbers as defined in the above is also specifically disclosed. Use of
the term
"optionally" with respect to any element of a claim means that the element is
required, or
alternatively, the element is not required, both alternatives being within the
scope of the claim.
Use of broader terms such as comprises, includes, and having should be
understood to provide
support for narrower terms such as consisting of, consisting essentially of,
and comprised
substantially of. Accordingly, the scope of protection is not limited by the
description set out
above but is defined by the claims that follow, that scope including all
equivalents of the subject
matter of the claims. Each and every claim is incorporated as further
disclosure into the
specification and the claims are embodiment(s) of the present invention. The
discussion of a
reference in the disclosure is not an admission that it is prior art,
especially any reference that
WO 2012/010853 CA 02805703 2013-01-16PCT/GB2011/001112
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has a publication date after the priority date of this application. The
disclosure of all patents,
patent applications, and publications cited in the disclosure are hereby
incorporated by
reference, to the extent that they provide exemplary, procedural or other
details supplementary
to the disclosure.
