1.Field of the Invention
The present disclosure relates generally to dividing a fluid flow between two or more
flow paths in a wellbore. More particularly, embodiments of the disclosure relate to systems
and methods that employ an actuator to selectively restrict flow through a first flow path
extending through a turbine, and thereby regulate the relative flow through at least one
second flow path.
2 . Background
Hydrocarbon drilling and production operations often require fluid flow systems to be
installed in a subterranean wellbore. For example, drilling systems often circulate a drilling
fluid (i.e., "mud' ") down-hole to provide lubrication to a drill bit and to carry geologic
cuttings from the bottom of the wellbore. The mud is generally circulated down-hole into the
wellbore through a drill string, out through the drill bit, and then back up to a surface location
through an annulus defined between the drill string and a wall of the wellbore. Fluid flow
systems are also installed for completion operations such as production and/or injection.
Production systems generally receive hydrocarbons, water or other fluids from the
subterranean formation through down-hole valves or other flow control devices, and then
deliver the fluids to a surface location through a string of production tubing. Injection
systems generally transport fluids from the surface to down-hole locations in the wellbore,
and then introduce the fluids into the subterranean formation.
Often, a portion of the fluid in a down-hole fluid flow system is split from a main
conduit and employed to achieve various down-hole objectives. For example, energy is often
extracted from these fluids for electricity generation, heat transfer, mechanically opening or
closing down-hole valves, or other types of actuation of down-hole tools. In many instances,
to extract the energy , the portion of the fluid split from the main conduit is diverted through a
down-hole turbine. The turbine may have a rotor arranged to turn in response to fluid flow
therethrough. The rotational motion can be transferred to a down-hole tool such as a drill bit,
an electrical generator, a hydraulic pump, a valve mechanism or other apparatus that can be
actuated by the rotational motion. In many instances, a bypass valve can be included in the
main conduit to divide the flow from the main conduit to distribute an appropriate portion of
the flow between a first path extending through the turbine and at least one second path that
bypasses the turbine. In some instances, the bypass valve can add unnecessary complexity to
the flow system.
BRIEF DESCRIPTION OF THE DRAWINGS
The disclosure is described in detail hereinafter on the basis of embodiments
represented in the accom panying figures, in which:
FIG. A is a schematic view of a drilling system that employs a flow splitting
mechanism in accordance with one or more exemplary embodiments of the disclosure;
FIG. IB is a schematic view of a well completion system including the flow splitting
mechanism of FIG. 1A;
FIG. 2 is a cross-sectional view of the flow splitting mechanism of FIG. 1A
illustrating a first flow path extending through a turbine and a second flow path bypassing the
turbine;
FIG. 3 is a schematic view of the flow splitting mechanism of FIG. 1A illustrating an
actuator for controlling stator blades positioned upstream of a rotor of the turbine of FIG. 2;
and
FIG. 4 is a flowchart illustrating an operational procedure employing the flow
splitting mechanism of FIG. 1A i accordance with example embodiments of the disclosure.
DETAILED DESCRIPTION
The disclosure may repeat reference numerals and/or letters in the various examples
or Figures. This repetition is for the purpose of simplicity and clarity and does not in itself
dictate a relationship between the various embodiments and/or configurations discussed.
Further, spatially relative terms, such as beneath, below, lower, above, upper, up-hole, downhole,
upstream, downstream, and the like, may be used herein for ease of description to
describe one element or feature's relationship to another element(s) or feature(s) as
illustrated, the upward direction being toward the top of the corresponding figure and the
downward direction being toward the bottom of the corresponding figure, the up-hole
direction being toward the surface of the wellbore, the down-hole direction being toward the
toe of the wellbore. Unless otherwise stated, the spatially relative terms are intended to
encompass different orientations of the apparatus in use or operation in addition to the
orientation depicted in the Figures. For example, if an apparatus in the Figures is turned
over, elements described as being "below" or "beneath" other elements or features would
then be oriented "above" the other elements or features. Thus, the exemplary term "below"
can encompass both an orientation of above and below. The apparatus may be otherwise
oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors
used herein may likewise be interpreted accordingly.
Moreover even though a Figure may depict a wellbore in a vertical wellbore, unless
indicated otherwise, it should be understood by those skilled in the art that the apparatus
according to the present disclosure is equally well suited for use in wellbores having other
orientations including vertical wellbores, slanted wellbores, multilateral wellbores or the like.
Likewise, unless otherwise noted, even though a Figure may depicts an offshore operation, it
should be understood by those skilled in the art that the apparatus according to the present
disclosure is equally well suited for use in onshore operations. Further, unless otherwise
noted, even though a Figure may depict a cased hole, it should be understood by those skilled
in the art that the apparatus according to the present disclosure is equally well suited for use
in open-hole operations.
· Description of Exemplary Embodiments
Referring to FIG. A, a directional drilling system 10 is one exemplary environment
in which aspects of the present disclosure may be practiced. The directional dri lling system
10 includes a down-hole flow splitting mechanism 100, according to one or more
embodiments of the present disclosure. Although directional drilling system 10 is illustrated
in the context of a terrestrial drilling operation, it will be appreciated by those skilled in the
art that aspects of the disclosure may also be practiced in connection with offshore platforms
and or other types of hydrocarbon exploration and recovery systems as well (see, e.g. , FIG.
B).
Directional dri lling system 0 is partially disposed within a directional wellbore 2
traversing a geologic formation "G." The directional wellbore 12 extends from a surface
location "S" along a curved longitudinal axis X[ In some exemplary embodiments, the
longitudinal axis includes a vertical section 12a, a build section 12b and a tangent section
12c. The tangent section 12c is the deepest section of the wellbore 12, and generally exhibits
lower build rates (changes in the inclination of the wellbore 2) than the build section 12b. In
some exemplary embodiments, the tangent section 12c is generally horizontal (see, e.g. , FIG.
B). Additionally, in one or more other exemplary embodiments, the wellbore 1 includes a
wide variety of vertical, directional, deviated, slanted and/or horizontal portions therein, and
may extend along any trajectory through the geologic formation "G."
A rotary drill bit 14 is provided at a down-hole location in the wellbore 2 (illustrated
in the tangent section 12c) for cutting into the geologic formation "G." When rotated, the
drill bit 14 operates to break up and generally disintegrate the geological formation "G." At
the surface location "S" a drilling rig 22 is provided to facilitate rotation of the drill bit 4 and
drilling of the wellbore 12. The drilling rig 22 includes a turntable 28 that generally rotates
the drill string 18 and the drill bit together about the longitudinal axis X . The turntable
28 is selectively driven by an engine 30, chain drive system or other or other apparatus.
Rotation of the drill string 18 and the drill bit 14 together may generally be referred to as
drilling in a "rotating mode," which maintains the directional heading of the rotary drill bit 4
and serves to produce a straight section of the wellbore 12, e.g., vertical section 12a and
tangent section 12c.
In contrast, a "sliding mode" may be employed to change the direction of the rotary
drill bit 14 and thereby produce a curved section of the wellbore 12, e.g. , build section 2b.
To operate in sliding mode, the turn table 28 may be locked such that the drill string 18 does
not rotate about the longitudinal axis X , and the rotary drill bit 14 may be rotated with
respect to the drill string 8. To facilitate rotation of the rotary drill bit 4 with respect to the
drill string 18, a bottom hole assembly or BHA 32 is provided in the drill string 8 at a downhole
location in the wellbore 12 . In the illustrated embodiment, the BHA 32 includes the
down-hole flow splitting mechanism 100 and a down-hole mud motor 34 that rotates the drill
bit 14 with respect to the drill string 18 in response to the flow of a drilling fluid such as
drilling mud 36 therethrough.
To actuate the mud motor 34, to carry away cuttings from the drill bit 14, to provide
support to the walls of the wellbore 2, and for other reasons appreciated by those skilled in
the art, drilling mud 36 can be pumped down-hole. A mud pump 38 pumps drilling mud 36
through an interior of the drill string 18, where mud 36 passes through the flow splitting
mechanism 00. A first portion of the mud 36 can be employed to drive the mud motor 34,
and a second portion of the mud 36 can be routed directly to the drill bit 14 to flush away
geologic cuttings, or to bearings (not explicitly shown) for lubrication, or to any other downhole
tools. The mud 36 is then returned through an annulus 40 defined between the drill
string 18 and the geologic formation "G." The geologic cuttings and other debris are carried
by the mud 36 to the surface location "S" where the cuttings and debris can be removed from
the mud stream.
Referring to FIG. IB, the flow splitting mechanism 100 may also be employed in
other down-hole environments such as completion system 50. The completion system 50 is
disposed in wellbore 52 that extend through the geologic formation "G." Wellbore 52 has a
substantially vertical section 54, the upper portion of which has cemented therein a casing
string 56. Wellbore 52 also has a substantially horizontal section 58 that extends through
hydrocarbon bearing geologic formation "G". As illustrated, substantially horizontal section
58 of wellbore 52 is open hole, e.g. , not including a casing string 56 therein.
Positioned within wellbore 52 and extending from the surface location "S" is a tubing
string 62. Tubing string 62 provides a conduit for formation fluids to travel from the
geologic formation "G" to the surface location "S" or for injection fluids to travel from the
surface location S to the geologic formation "G." At its lower end, tubing string 62 is
coupled to a completion string 64 that has been installed in wellbore 52. The completion
string 64 is divided into a plurality of intervals by packers 66, which seal between the
completion string 64 and the geologic formation "G". The completion string 64 includes a
plurality of fluid flow control systems 68, which may include valves, screens or other
mechanisms for controlling the flow of fluids into or out of the completion string 64.
In the illustrated embodiment, a flow splitting mechanism 100 is disposed adjacent
each of the flow control systems 68. In other embodiments, other arrangements are
contemplated such as arrangements where only a single flow splitting mechanism 100 is
provided in the wellbore 52, or aiTangements where multiple flow spitting mechanisms 100
adjacent each flow control system 68, depending on the operational objectives of completion
system 50. In some exemplary embodiments, formation fluids enter completion string 64
through the flow control systems 68, and then flow through the flow spl itting mechanisms
100 travel ing up-hole toward tubing string 62. The flow splitting mechanism 100 can divert a
portion of the formation fluids through a turbine (not explicitly illustrated in FIG. IB) to
provide power for operating the flow control system 68. In other embodiments, the flow
splitting mechanism 100 can be operably coupled to the packers 66, or to other down-hole
tools as will be appreciated by those skilled in the art.
Referring now to FIG. 2, a flow splitting mechanism 100 in accordance with aspects
of the present disclosure is illustrated. The flow splitting mechanism 100 is arranged in a
main conduit 1 2 for dividing a main flow in a main flow path (represented by arrow Ao) into
distinct or separate flow paths. As described above, in some exemplary embodiments, the
main conduit 02 may comprise a drill string 8 (FIG. 1A), a tubing string 62, a completion
string 64 (FIG. B) or any other down-hole fluid conduit as will be appreciated by those
skilled in the art. The flow splitting mechanism 00 divides fluid flow from the main flow
path Ao into a first flow i a first flow path (represented by arrows A ) that extends through a
turbine assembly 104 and a second flow path (represented by arrows AV), which bypasses the
turbine assembly 104. In some exemplary embodiments, the turbine assembly 104 can
comprise any mechanism responsive to the circulation of a fluid therethrough to generate
rotational motion. In some exemplary embodiments, the turbine assembly 104 can be a mudmotor
mechanism, and in some exemplary embodiments, the turbine assembly 104 ca be a
positive-displacement motor, sometimes referred to as a Moineau-type motor.
The turbine assembly 04 includes a stator 108 and a rotor 110. In some exemplary
embodiments, the stator 108 is mounted in a stationary manner with respect to the main
conduit 02, and is arranged to remain stationary as fluid flows there past. The exemplary
stator 108 includes a generally cylindrical body 112 with a conical leading end 114. A
plurality of stator blades 1 6 protrude from the generally cylindrical body 12 and curve in a
helical pattern toward a trailing end 118 of the stator 108. In some exemplary embodiments,
the stator blades 16 are operable to maintain a generally stationary position with respect to
the main conduit 102. For example, the stator blades 116 may maintain a non-rotating
position (e.g., about a longitudinal axis of the turbine assembly 04) with respect to the
main conduit 02 in response to fluid flow thereby.
In other embodiments, stator blades (not shown) may be provided in other
configurations such as generally straight configurations, and/or configurations wherein stator
blades (not shown) are provided that protrude inward from an interior wall of the main
conduit 102. The stator blades 116 define flow channels there between and operate to direct
the fluid flow through the first flow path (A ) onto the rotor 110. The position and
orientation of the stator blades 116 define an angle of attack for engaging the rotor 110 with
the fluid. The rotor 110 includes a generally cylindrical body 122 with a conical trailing end
124. A plurality of rotor blades 126 protrude from the cylindrical body 122 of the rotor 110
and curve in a helical pattern toward the trailing end 124. The rotor blades 126 curve in an
opposite direction than the stator blades 6 of the stator 08, and thus, fluid directed by
stator blades 6 of the stator 108 engage the rotor blades 26 of the rotor 10 and transfer
energy to the rotor blades 126 to cause the rotor 10 to rotate about the longitudinal axis 2
of the turbine assembly 104.
A flow splitter 130 is positioned within the main conduit 102 and defines the first and
second fluid flow paths (A] and A ) extending from a main flow path Ao in the main conduit
102. In some exemplary embodiments, the flow splitter 30 includes a tubular member
arranged to at least partially circumscribe the stator 108 and rotor 10. A leading end 130a of
the flow splitter 30 is tapered to direct a portion of the fluid flow into each of the fluid flow
paths A , A2, and thereby divide the fluid flow between the first and second flow paths A ,
A2. The first flow path A i extends through an interior of the flow splitter 130 and through the
turbine assembly 104. The second flow path A2 extends through an annulus defined between
an exterior of the flow splitter 130 and the main conduit 102 such that fluid flow through the
second fluid flow path A2 bypasses the stator 108 and rotor 110. The flow splitter 130
defines a boundary between the first and second fluid flow paths Ai, A , and thus the flow
characteristics (flow resistance, pressure, volume, viscosity, etc.) maintainable within each of
the fluid paths Ai, A2 may be distinct and different from one another. In some exemplary
embodiments, there is no fluid communication between the first and second fluid flow paths
A], A2 downstream of the leading end 130a of the flow splitter 130. In other exemplary
embodiments, apertures (not shown) may be provided in the flow splitter 130, or conduits
(not shown) may be provided that extend between the first and second fluid flow paths A , A2
providing some degree of fluid communication between the first and second fluid flow paths
A,, A2.
At the trailing end 124 of the rotor 110, the first and second flow paths Ai, A
recombine in the main conduit 102. In other exemplary embodiments, the second flow path
A may extend to a supplemental tool 132 (FIG. 3), directly to a drill bit 14 (FIG. A) for
removing cuttings, or may extend to other down-hole locations. In some exemplary
embodiments, the supplemental tool 132 may include a supplemental turbine assembly,
hydraulically activated tools and/or the drill bit 4 (FIG. 1A).
The rotor 110 is operably coupled to a down-hole tool 134. In some exemplary
embodiments, the down-hole tool 134 is directly coupled to the rotor 110 to receive torque or
rotational motion from the rotor 0. In some exemplary embodiments the down-hole tool
34 may include an electric generator, a hydraulic pump, an, off-center vibratory tool cutting
tool, a valve mechanism or tools recognized in the art. In some operational embodiments, the
down-hole tool 134 may have speed requirements or optimal operating ranges that can be
accommodated by a particular range of flow rates or other flow characteristics flowing
through the first flow path A . Thus, the flow rate through the first flow path A may be
selectively adjusted within the particular range without compromising operational
characteristics of the down-hole tool 134. By adjusting the flow characteristics through the
first flow path A , the flow characteristics through the second flow path A2 (and
correspondingly a flow ratio between the first and second flow paths A i and A2) may thereby
be adjusted as well.
Referring now to FIG. 3, the flow splitting mechanism 100 includes an adjustment
mechanism 142. The adjustment mechanism 142 is operably coupled to one or more of the
stator blades 1 6 of the stator 108 to adjust a pitch, orientation, or position of the stator
blades 116 with respect to the generally cylindrical body 2 of the stator 108. The
adjustment mechanism 142 is thus operable to control a flow area of the first flow path A i,
and also to thereby control a flow ratio between the first and second flow paths A and A2.
The adjustment mechanism 142 is operable to selectively limit or restrict flow through the
first flow path At, and in some exemplary embodiments, the adjustment mechanism 142 is
operable to completely close the first flow path A \ . For example, the first flow path A may
be closed by engaging the stator blades 116 with the flow splitter 130, and/or with one
another. By controlling the flow though the flow path A , the speed of the down-hole tool
134 can be controlled. Similarly, by controlling the flow through the first flow path A i, the
relative flow through the second flow path A2 may also be controlled. n some exemplary
embodiments, the second flow path A2 is fluidly coupled to the supplemental tool 132, and
thus, by controlling the relative flow through the second flow path A2, the relative flow to the
supplemental tool 132 may also be controlled.
The adjustment mechanism 142 includes a controller 144, which is operably and
communicatively coupled to one or more actuators 148. As illustrated, each individual
actuator 148 is coupled to an individual stator blade 6, and thus, each stator individual
blade 6 can be adjusted independently of any of the other stator blades 116. In other
exemplary embodiments (not shown), a single actuator 148 may be arranged to adjust a
plurality of the stator blades 1 6 simultaneously or sequentially. In still other embodiments,
one or more of the stator blades 116 may be mounted in a fixed or stationary manner with
respect to the generally cylindrical body 112 of the stator 108, while one or more of the other
stator blades 6 are operably coupled to an actuator 148 for selectively moving with respect
to cylindrical body 12. In exemplary embodiments, the adjustment mechanism 142 may be
operable to adjust the position of any subset of the stator blades 1 6. In some exemplary
embodiments, the actuators 148 can include pneumatic or hydraulic pistons, a bevel gear
assembly, a rack and pinion or a guide plate. In some exemplary embodiments, the actuator
may include a motor such as an electric rotary motor or a linear motor. In some exemplary
embodiments, the motor may be directly coupled to a stator blade 11 with a shaft coupling
or other mechanism recognized i the art. In any event, controller 144 is operatively and
communicatively coupled to the actuators 148 such that the controller 144 can selectively
instruct the actuators 48, and receive feedback therefrom. In some exemplary embodiments,
the actuator 48 may be operable to provide positional infonnation to the controller 44 such
that an intended adjustment may be verified.
In some embodiments, the controller 144 may include a computer having a processor
144a and a computer readable medium 144b operably coupled thereto. The computer
readable medium 144b can include a nonvolatile or non-transitory memory with data and
instructions that are accessible to the processor 144a and executable thereby. In one or more
embodiments, the computer readable medium 144b is pre-programmed with predetermined
sequences of instructions for operating the actuators 148 to achieve various objectives as
described in greater detail below. In one or more embodiments, instructions may be
communicated to the controller 144 in real time from the surface location "S" or from other
down-hole locations.
In o e or more embodiments, adj ustment mechanism 142 optionally includes one or
more feedback devices 50. The controller 144 is communicatively coupled to feedback
devices 150, which are operable to detect and/or react to an environmental characteristic, and
to provide a feedback signal representative of the environmental characteristic to the
controller 144. In one or more embodiments, one or more of the feedback devices 150 are
flow rate feedback devices operable to detect and/or react to an environmental characteristic
from which a flow rate is determinable or estimable. As used herein, the term
"representative" means at least that one signal, pressure or quantity is directly correlated,
associated by mathematical function, and/or otherwise determinable or estimable from
another signal pressure or quantity. In one or more embodiments, one or more feedback
devices 50 may be positioned to measure a flow rate within the first flow path A \ and one
or more feedback devices 150 may be positioned to measure a flow rate in the second flow
path A?. Among other operations, the feedback devices 150 to provide information to the
control ler 144 from which the controller 144 may determine a position of the stator blades
116.
In some exemplary embodiments, the feedback devices 150 may include temperature
sensors operable to detect a temperature of the fluid flowing through the first and second flow
paths A i, A and/or a temperature of down-hole components in thermal communication with
the fluid flowing through the first and second flow paths A and A . For example, the
feedback devices 150 may operate to detect a temperature of a housing (not explicitly
depicted) of the turbine assembly 104, the flow splitter 130 and/or the main conduit 02. In
some exemplary embodiments, the controller 144 may be pre-programmed with a threshold
temperature above or below which more or less fluid can be directed through the flow paths
A and A 2 . In this manner, more fluid may be directed through the particular flow path A or
A in thermal contact with components that may require additional cooling.
A communication unit 152 may be provided in operative communication with the
control ler 144. In some embodiments, the communication unit 152 can serve as both a
transm itter and receiver for communicating signals between the controller 44 and a surface
unit 154, or for communicating signals between the controller 144 and another down-hole
component. For example, the communication unit 152 can transmit data signals from
feedback devices 150 to the surface unit 154 for evaluation by an operator. The
communication unit 1 2 can also serve as a receiver for receiving data or instructions from
the surface unit 154. In some exemplary embodiments, the surface unit 54 and the
communication unit 52 are communicatively coupled to one another any type of telemetry
system or any combination of telemetry systems, such as electromagnetic, acoustic and\or
wired pipe telemetry systems for two-way communication between the surface unit 154 and
the communication unit 52. The communication unit 152 may transmit data collected from
the feedback devices 150 or information from the controller 44 in an up-hole direction to the
surface unit 154 to be interpreted thereby, and the surface unit 154 may transmit instructions
for the controller 144 in a down-hole direction to the commun ication unit 152.
2. Example Implementation
Referring now to FIG. 4, and with reference to FIGS. 1A through 3, some exemplary
embodiments of operational procedures 200 that employ the flow splitting mechanism 100
are described. In some exemplary embodiments, the operational procedures 200 serve to
control an erosion rate within the turbine assembly 104 or on an exterior of the turbine
assembly, e.g. , by selectively reducing a proportion of a main flow A flowing through or
around the turbine assembly 104, respectively. In other exemplary embodiments, the
operational procedure 200 serves to divert a portion of the main flow A0 for cooling portions
of the turbine assembly 104 or other down-hole components, for actuating a supplemental
tool 32, to operate an additional turbine assembly, or to achieve other flow splitting
objectives recoginzed in the art.
Initially at step 202, a target flow distribution between first and second down-hole
flow paths A and A is determined. The target flow distribution can be determ ined based on
functions to be performed by the flow through the first and second flow paths A and A2. For
instance, when the flow splitting mechanism 00 is deployed in a drilling system 10 (FIG.
1A), the target flow distribution may be based on a required flow through the first flow path
A extending through the turbine assembly 04 to drive the drill bit 14, and also a required
flow through the second flow path A to sufficiently flush cuttings from the drill bit 14. In
some exemplary embodiments, a tolerance with respect to the target flow distribution may be
determined and preprogrammed onto the controller prior to deploying the adjustment
mechanism 42 into the wel !bore 2.
At step 204, the main flow Ao is split between the first flow path A and the second
flow path A2 to establish a first flow distribution there between. The flow distribution
between the first and second flow paths A \ and A2 is established, at least in part, due to a
resistance to flow through tubular member of the flow splitter 130. For instance, the
available flow area through the flow splitter 30 and the angle of attack established by the
blades of the stator 108 affect the flow resistance through the flow splitter 130, and thus
affect the flow through the first and second flow paths first flow path A and A .
Next, at decision 206, a determination is made whether a difference between the first
flow distribution and the target flow distribution is outside a predetermined tolerance. This
determination may be made based on information provided by the feedback devices 150, or
by other methods recognized in the art. For example, where target flow distribution is
defined to provide sufficient flushing of cuttings from a drill bit 4, for example, and where a
slower drilling rate than expected is realized, a determination may be made that cuttings are
not being effectively flushed form the drill bit 4 due to an insufficient flow through the
second flow path A2. Accordingly, a determination can be made that the difference between
the first flow distribution and the target flow distribution is outside the predeterm ined
tolerance. In some exemplary embodiments, the determination is made by a operator at the
surface location "S" and in some embodiments; the determination is made by the controller
44.
n some exemplary embodiments, determining that a difference between the first flow
distribution and the target flow distribution is outside a predetermined tolerance comprises
determ ining that a temperature of a component in thermal communication with one of the
first and second flow paths Ai and A is greater than a predetermined threshold temperature.
The predetermined threshold temperature may be pre-programmed onto the controller 144,
and data from the feedback devices 150 may assist in determining if the temperature of
particular down-hole component may be outside a tolerance. The down-hole component may
be heated or cooled by greater or lesser fluid flow thereby or therethrough.
Where the tolerance is exceeded, the procedure continues to step 208 where an
adjustment to the stator blades 116 may be initiated as described below. Where the tolerance
is not exceeded, e.g. , where it is determined at decision 208 that a difference between the first
flow distribution and the target flow distribution is not outside of the predetermined
tolerance, operations may continue with no immediate adjustments to stator blades 116, and
the procedure 200 returns to step 202 where a new target flow distribution may be
determined.
At step 208, one or more of the actuators 148 are activated. In some exemplary
embodiments, an operator at the surface location "S" transmits a signal from the surface unit
1 4 down hole to the communication unit 52, which receives the signal and converts the
signal to a form readable by the controller 44. The controller 144 in turn, reads and
interprets the signal, and then instructs the one or more actuators 48 based on the signal to
move one or more of the stator blades 116 with respect to the cylindrical body 11 of stator
08. The movement of the stator blades 116 adjusts the resistance to flow through the turbine
assembly 104 by adjusting a flow area through the flow splitter 130, or by adjusting a pitch of
one or more of the stator blades 116 to obstruct or facilitate flow of the through the second
flow path A . By adjusting the resistance of flow through the first flow path Ai, a second
flow distribution between the first and second paths A and A2 is established.
Next, at decision 2 10, a determination is made whether a difference between the
second flow distribution and the target flow distribution is within the predetermined
tolerance. This determ ination may again be made based on information provided by the
feedback devices 50, or by other methods recognized in the art. For example, if the drill ing
rate increases with the second flow distribution, a determination can be made that tire second
flow distribution is appropriate to continue operations. The procedure 200 may then again
return to step 202 where a new target flow distribution can be determined. Where the second
flow distribution is not appropriate, e.g. , where the difference between the second flow
distribution and the target flow distribution is outside the predetermined tolerance, the
procedure 200 returns to step 208 where further adjustments to the stator blades may be
made.
3. Aspects of the Disclosure
In one aspect, the disclosure is directed to a system for dividing flow in a wellbore.
The system includes a main conduit defining a main flow path therethrough, and a flow
splitter in positioned in fluid communication with the main conduit downstream of the main
flow path. The flow spl itter defines first and second distinct fluid flow paths extending from
the main flow path. The system also includes a turbine assembly in fluid communication
with the first flow path downstream of the flow splitter. The turbine assembly includes a
stator disposed within the first flow path and having a plurality of stator blades operable to
maintain a generally stationary position with respect to the main conduit during fluid flow
through the first flow path. The turbine also includes a rotor responsive to the fluid flow
through the first flow path to rotate with respect to the stator, and an actuator coupled to at
least one of the stator blades. The actuator is operable to move the at least one stator blade to
adjust a flow resistance through the first flow path.
In one or more exemplary embodiments, the stator comprises an elongate body
disposed within the first flow path, and the plurality of stator blades protrudes radially
outward from the elongate body to define flow channels there between. In some
embodiments, the elongate body includes a generally cylindrical body, and the plurality of
stator blades protrudes radially from the generally cylindrical body to define flow channels
there between. In some embodiments, the stator blades curve in a helical manner toward a
trail ing end of the stator. In some exemplary embodiments, the generally stationary position
of the stator blades may include a non-rotating position about a longitudinal axis of the
turbine assembly.
In exemplary embodiments, the flow splitter includes a leading edge of a tubular
member disposed within the main conduit, and wherein the stator is at least partially disposed
within an interior of the tubular member. The second fluid flow path may extend through an
annu!us defined between an exterior of the tubular member and the main conduit such that
fluid flow through the second fluid flow path bypasses the stator and rotor. In one or more
exemplary embodiments, the system further includes a supplemental tool in fluid
communication with the second fluid flow path, and the supplemental tool comprises at least
one of a turbine assembly, a hydraulically activated tool and a drill bit.
In one or more exemplary embodiments, the actuator comprises at least one of the
group consisting of a bevel gear assembly, a rack and pinion and a guide plate. In some
exemplary embodiments, one or more of the stator blades is mounted in a fixed manner with
respect to a body of the stator. In some exemplary embodiments, at least one stator blade is
independently adjustable from another stator blade.
In another aspect, the present disclosure is directed to a method of dividing flow in a
wellbore. The method includes (a) deploying a main conduit into a wellbore, (b) splitting a
main flow of fluid in the main conduit between a first flow path and a second flow path, (c)
flowing fluid through the first flow path to engage at least one stator blade and a rotor of a
turbine assembly, (d) maintaining the at least one stator blade in a first stationary position
with respect to the main conduit to establish a first flow distribution between the first and
second flow paths, (e) moving the at least one stator blade to a second stationary position
with respect to the main conduit to adjust a resistance to flow in the first flow path, and (f)
maintaining the at least one stator blade i the second stationary position with respect to the
main conduit to establish a second flow distribution between the first and second flow paths.
In one or more exemplary embodiments, moving the at least one stator blade to the
second stationary position comprises activating an actuator operably coupled to the at least
one stator blade. In some embodiments, activating the actuator comprises transmitting a
signal to a controller operably coupled to the actuator and preprogrammed with a series of
instructions for moving the at least one stator blade.
In some embodiments, the method further includes determining that a difference
between the first flow distribution and a target flow distribution is outside a predetermined
tolerance. In some exemplary embodiments, the predeterm ined tolerance is preprogrammed
onto the controller prior to deploying the main conduit into the wel lbore. In one or more
exemplary embodiments, determ ining that a difference between the first flow distribution and
the target flow distribution is outside a predetermined tolerance comprises determining that a
temperature of a component in thermal communication with one of the first flow path and is
greater than a predetermined threshold temperature.
In another aspect, the present disclosure is directed to a down-hole flow system
including a main conduit extending through a subterranean formation and defining a main
flow path therethrough. A flow splitter is positioned downstream of the main flow path and
is operable to divide flow from the main flow path into first and second fluid flow paths
extending from the main flow path. A rotor is disposed in the first flow path and is rotatable
in the first flow path in response to a fluid flow through the first flow path. A stator is
disposed in the first flow path. The stator includes a body and a plurality of stator blades
extending from the body to guide the fluid flow into the rotor. The down-hole flow system
also includes an adjustment mechanism operable to adjust a flow area defined by the first
flow path. The adjustment mechanism includes an actuator and a controller. The actuator is
operably coupled to at least one stator blade to move the at least one stator blade between
first stationary position with respect to the body wherein a first flow area is defined through
the f i st flow path, and a second stationary position with respect to the body wherein a second
flow area is defined through the first flow path that is different than the first flow area. The
controller is operably coupled to the actuator to selectively induce the actuator to move the at
least one stator blade between the first and second positions.
In some exemplary embodiments, the main conduit includes at least one of the group
consisting of a drill string, a production string and an injection string. In some exemplary
embodiments, the down-hole flow system further includes a down-hole communication unit
operably coupled to the controller. The down-hole communication unit may be operable to
communicate with a surface unit disposed at a surface location outside the subterranean
formation. In some exemplary embodiments, the controller is operable to determine a blade
position, and in some exemplary embodiments, the communication unit is operable to
transmit the blade position to the surface unit.
In one or more exemplary embodiments, the flow splitter includes a tubular member
circumscribing at least a portion of the stator and the rotor such that the first flow path is
defined on an interior of the tubular member and the second flow path is defined on the
exterior of the tubular member. In some embodiments, the second flow area through the
tubular member is fully closed when the at least one stator blade is in the second stationary
position. In some exemplary embodiments, the adjustment mechanism is operable to move a
subset of the plurality of stator blades.
Moreover, any of the methods described herein may be embodied within a system
including electronic processing circuitry to implement any of the methods, or in a computerprogram
product including instructions which, when executed by at least one processor,
causes the processor to perform any of the methods described herein.
The Abstract of the disclosure is solely for providing the United States Patent and
Trademark Office and the public at large with a way by which to determine quickly from a
cursory reading the nature and gist of technical disclosure, and it represents solely one or
more embodiments.
While various embodiments have been il lustrated in detail, the disclosure is not
limited to the embodiments shown. Modifications and adaptations of the above embodiments
may occur to those skilled i the art. Such modifications and adaptations are i the spirit and
scope of the disc losure.

CLAIMS
WHAT IS CLAIMED IS:
1. A system for dividing flow in a wellbore, the system comprising:
a main conduit defining a main flow path therethrough;
a flow splitter positioned in fluid communication with the main conduit downstream
of the main flow path, the flow splitter defining first and second fluid flow paths extending
from the main flow path; and
a turbine assembly i fluid communication with the first flow path downstream of the
flow splitter, the turbine assembly comprising:
a stator within the first flow path, the stator including a plurality of stator
blades operable to maintain a general ly stationary position with respect to the mai conduit
during fluid flow through the first flow path;
a rotor responsive to the fluid flow through the first flow path to rotate with
respect to the stator; and
an actuator coupled to at least one of the stator blades, the actuator operable to
move the at least one stator blade to adjust a flow resistance through the first flow path.
2. The system of claim 1, wherein the stator comprises an elongate body within the first
flow path, and wherein the plurality of stator blades protrudes radially outward from the
elongate body to define flow channels there between.
3. The system of claim 2, wherein the flow splitter comprises a leading edge of a tubular
member within the main conduit, and wherein the stator is at least partially within an interior
of the tubular member.
4. The system of claim 3, wherein the second fluid flow path extends through an annulus
defined between an exterior of the tubular member and the conduit such that fluid flow
through the second fluid flow path bypasses the stator and rotor.
5. The system of claim 1, wherein the actuator comprises at least one of the group
consisting of a bevel gear assembly, a rack and pinion, a guide plate, and a direct coupling to
a motor.
6. The system of claim 1, wherein one or more of the stator blades is mounted in a fixed
manner with respect a body of the stator.
7. The system of claim 1, wherein at least one stator blade is independently adjustable
from another stator blade.
8. The system of claim 1, further comprising a supplemental tool in fluid communication
with the second fluid flow path, and wherein the supplemental tool comprises at least one of a
turbine assembly, a hydraulically activated tool and a drill bit.
9. A method of dividing flow in a wellbore, the method comprising:
deploying a main conduit into a wellbore;
splitting a main flow of fluid in the main conduit between a first flow path and a
second flow path;
flowing fluid through the first flow path to engage at least o e stator blade and a rotor
of a turbine assembly;
maintaining the at least one stator blade in a first stationary position with respect to
the main conduit to establish a first flow distribution between the first and second flow paths;
moving the at least one stator blade to a second stationary position with respect to the
main conduit to adjust a resistance to flow in the first flow path; and
maintaining the at least one stator blade in the second stationary position with respect
to the main conduit to establish a second flow distribution between the first and second flow
paths.
0. The method of claim 9, wherein moving the at least one stator blade to the second
stationary position comprises activating an actuator operably coupled to the at least one stator
blade.
1 . The method of claim 0, wherein activating the actuator comprises transm itting a
signal to a controller operably coupled to the actuator and preprogrammed with a series of
instructions for moving the at least one stator blade.
2 . The method of claim 1 , further comprising determining that a difference between the
first f ow distribution and a target flow distribution is outside a predeterm ined tolerance.
13. The method of claim 12, wherein determining that a difference between the first flow
distribution and the target flow distribution is outside a predetermined tolerance comprises
determining that a temperature of a component in thermal communication with one of the
first flow path and is greater than a predetermined threshold temperature.
4 . A down-hole flow system, comprising:
a main conduit extending through a subterranean formation and defining a main flow
path therethrough:
a flow splitter positioned downstream of the main flow path and operable to divide
flow from the main flow path into first and second fluid flow paths extending from the main
flow path;
a rotor in the first flow path and rotatable in the first flow path in response to a fluid
flow through the first flow path;
a stator in the first flow path, the stator including a body and a plurality of stator
blades extending from the body to guide the fluid flow into the rotor; and
an adjustment mechanism operable to adjust a flow area defined by the first flow path;
the adjustment mechanism comprising:
an actuator operably coupled to at least one stator blade to move the at least
one stator blade between first stationary position with respect to the body wherein a first flow
area is defined through the first flow path, and a second stationary position with respect to the
body wherein a second flow area is defined through the first flow path that is different than
the first flow area; and
a controller operably coupled to the actuator to selectively induce the actuator
to move the at least one stator blade between the first and second positions.
15. The down-hole flow system of claim 14, wherein the main conduit includes at least
one of the group consisting of a drill string, a production string and an injection string.
16. The down-hole flow system of claim 14, further comprising a down-hole
communication unit operably coupled to the controller, wherein the down-hole
communication unit is operable to communicate with a surface unit at a surface location
outside the subterranean formation.
17. The down-hole flow system of claim 16, wherein the controller is operable to
determine a stator blade position, and wherein the communication unit is operable to transmit
the stator blade position to the surface unit.
1 . The down-hole flow system of claim 14, wherein the flow splitter comprises a tubular
member circumscribing at least a portion of the stator and the rotor such that the first flow
path is defined on an interior of the tubular member and the second flow path is defined on
the exterior of the tubular member.
1 . The down-hole flow system of claim 1 , wherein the second flow area through the
tubular member is fully closed when the at least one stator blade is i the second stationary
position.
20 The down-hole flow system of claim 14, wherein the adjustment mechanism is
operable to move a subset of the plurality of stator blades.