U.S. patent application number 14/303776 was filed with the patent office on 2015-12-17 for cable-conveyed activation object.
The applicant listed for this patent is Schlumberger Technology Corporation. Invention is credited to Theodore Lafferty, Matthew J. Miller, John R. Whitsitt.
Application Number | 20150361761 14/303776 |
Document ID | / |
Family ID | 54835735 |
Filed Date | 2015-12-17 |
United States Patent
Application |
20150361761 |
Kind Code |
A1 |
Lafferty; Theodore ; et
al. |
December 17, 2015 |
CABLE-CONVEYED ACTIVATION OBJECT
Abstract
A technique that is usable with a well includes deploying a
cable-conveyed object in a passageway of a string in the well;
using the object to sense a property of an environment of the
string and communicating an indication of the sensed property to an
Earth surface of the well; remotely controlling an operation of the
object to change a state of a first downhole valve assembly based
at least in part on the communication; and using the object to
control a state of the other downhole valve assembly(ies) during
deployment of the object in the well.
Inventors: |
Lafferty; Theodore; (Sugar
Land, TX) ; Whitsitt; John R.; (Houston, TX) ;
Miller; Matthew J.; (Katy, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Schlumberger Technology Corporation |
Sugar Land |
TX |
US |
|
|
Family ID: |
54835735 |
Appl. No.: |
14/303776 |
Filed: |
June 13, 2014 |
Current U.S.
Class: |
166/250.01 ;
166/65.1 |
Current CPC
Class: |
E21B 34/14 20130101;
E21B 23/14 20130101; E21B 47/092 20200501; E21B 47/095
20200501 |
International
Class: |
E21B 34/06 20060101
E21B034/06; E21B 43/26 20060101 E21B043/26; E21B 33/12 20060101
E21B033/12; E21B 43/25 20060101 E21B043/25; E21B 47/00 20060101
E21B047/00 |
Claims
1. A method usable with a well, comprising: deploying a
cable-conveyed object in a passageway of a string in the well;
using the object to sense a property of an environment of the
string and communicating an indication of the sensed property to an
Earth surface of the well; remotely controlling an operation of the
object to change a state of a first downhole valve assembly based
at least in part on the communication; and using the object to
control a state of at least one other downhole valve assembly
during deployment of the object in the well.
2. The method of claim 1, wherein the property comprises a physical
property.
3. The method of claim 2, wherein the physical property comprises a
magnetic field produced by a magnetic marker, a geometric
discontinuity of the string, an acoustic wave, a pressure or a
conductivity.
4. The method of claim 2, wherein the physical property comprises
an element selected from the group consisting essentially of a
dedicated marker, a radioactive source, a magnetic, a
microelectromechanical system (MEMS)-based marker and a
pressure.
5. The method of claim 1, wherein deploying the cable-conveyed
object comprises deploying the object on a wireline or a
slickline.
6. The method of claim 1, further comprising using the first
downhole valve assembly to perform a stimulation operation.
7. The method of claim 1, wherein remotely controlling the
cable-conveyed object comprises transitioning the object between a
radially contracted state and a radially expanded state.
8. The method of claim 1, wherein using the object sense the
property comprises sensing a repeating pattern along the string or
sensing a feature of the well primarily associated with a function
other than identifying a downhole location.
9. The method of claim 1, wherein using the cable-conveyed object
to sense the property comprises sensing a dedicated location
identification marker, sensing a current in a coil of the object or
sensing a magnetic field.
10. The method of claim 1, wherein remotely controlling the
cable-conveyed object further comprises forming a downhole
obstruction inside the passageway of the string.
11. The method of claim 1, wherein communicating the indication
comprises communicating with the Earth surface using tension-based,
acoustic-based, electrical signal-based, or electromagnetic
wave-based telemetry.
12. The method of claim 1, further comprising: perforating a
segment of the well; using the first downhole valve assembly to
fracture the segment of the well; perforating at least one other
segment of the well; and using a fluid obstruction formed by the at
least one other downhole valve assembly to fracture the at least
one other segment of the well.
13. The method of claim 12, wherein perforating the first segment
and perforating the at least one other segment comprises using a
perforating gun disposed on the object.
14. A method usable with a well, comprising: deploying a
cable-conveyed object in a passageway of a string in the well;
using the object to detect a location of the object and communicate
an indication of the location to the Earth surface of the well; in
response to the indication, remotely controlling operation of the
object from the Earth surface to cause the object to engage a first
valve assembly to change a state of the first valve assembly; and
remotely controlling operation of the object from the Earth surface
to cause the object to engage at least one additional valve
assembly while the object is deployed in the well to change a state
of the at least one additional valve assembly.
15. The method of claim 14, wherein remotely controlling operation
of the object from the Earth surface comprises remotely controlling
the object to cause the object to radially expand to engage a
sleeve of the valve assembly.
16. The method of claim 14, wherein remotely controlling the object
comprises remotely controlling the object to form a fluid barrier
in the string.
17. The method of claim 14, wherein remotely controlling the object
comprises remotely controlling the object to shift the valve
assembly between open and closed states.
18. The method of claim 14, wherein remotely controlling the valve
comprises radially expanding the valve to lodge the valve in a
sleeve of the valve assembly and create a fluid barrier, the method
further comprising: using the fluid barrier to pressurize the
string to hydraulically shift the sleeve to cause the valve
assembly to transition from a first state to a second state; and
using the fluid barrier to divert fluid to perform a stimulation
operation in a stage associated with the valve assembly with the
valve assembly in the second state.
19. The method of claim 18, further comprising: remotely
controlling the object from the Earth surface to cause the object
to radially retract; moving the object to another valve assembly in
the well; using the object transition the other valve assembly from
a first state to a second state; and performing another stimulation
operation in another stage associated with the other valve assembly
with the other valve assembly being in the second state.
20. A method of claim 18, wherein the stimulation operation
comprises a hydraulic fracturing operation.
21. An apparatus usable with a well, comprising: a conveyance
cable; and an object adapted to be deployed in the well using the
cable, the object comprising: a sensor to sense an environment of
the object; a telemetry interface; an actuator; an expandable
element; and a control system to: use the sensed environment to
determine a location of the object; use the telemetry interface to
communicate an indication of the location uphole; use the actuator
to selectively expand the expandable element to engage a first
valve assembly in response to receiving a first remotely
communicated stimulus; use the actuator to retract the expandable
element in response to receiving a second remotely communicated
stimulus; and use the actuator to expand the expandable element to
actuate a second valve assembly in response to receiving a third
remotely communicated stimulus.
22. The apparatus of claim 21, wherein the sensor is adapted to
sense at least one of a conductivity, an electromagnetic coupling,
a magnetic field and a radioactivity.
23. The apparatus of claim 21, further comprising: a string
comprising a plurality of valve assemblies, each of the valve
assemblies being sized to catch an object having substantially the
same size; and the cable-conveyed object is adapted to pass through
at least one of the valve assemblies and controllably expand to
said same size to cause capture of the cable-conveyed tool by one
of the valve assemblies.
Description
BACKGROUND
[0001] For purposes of preparing a well for the production of oil
or gas, at least one perforating gun may be deployed into the well
via a conveyance mechanism, such as a wireline or a coiled tubing
string. The shaped charges of the perforating gun(s) are fired when
the gun(s) are appropriately positioned to perforate a casing of
the well and form perforating tunnels into the surrounding
formation. Additional operations may be performed in the well to
increase the well's permeability, such as well stimulation
operations and operations that involve hydraulic fracturing. The
above-described perforating and stimulation operations may be
performed in multiple stages of the well.
SUMMARY
[0002] The summary is provided to introduce a selection of concepts
that are further described below in the detailed description. This
summary is not intended to identify key or essential features of
the claimed subject matter, nor is it intended to be used as an aid
in limiting the scope of the claimed subject matter.
[0003] In an example implementation, a technique that is usable
with a well includes deploying a cable-conveyed object in a
passageway of a string in the well; using the object to sense a
property of an environment of the string and communicating an
indication of the sensed property to an Earth surface of the well;
remotely controlling an operation of the object to change a state
of a first downhole valve assembly based at least in part on the
communication; and using the object to control a state of at least
one other downhole valve assembly during deployment of the object
in the well.
[0004] In another example implementation, a technique that is
usable with a well includes deploying a cable-conveyed object in a
passageway of a string in the well; using the object to detect a
location of the object and communicate an indication of the
location to the Earth surface of the well; in response to the
indication, remotely controlling operation of the object from the
Earth surface to cause the object to engage a first valve assembly
to change a state of the first valve assembly; and remotely
controlling operation of the object from the Earth surface to cause
the object to engage at least one additional valve assembly while
the object is deployed in the well to change state(s) of the
additional valve assembly(ies).
[0005] In yet another example implementation, an apparatus that is
usable with a well includes a conveyance cable and an object that
is adapted to be deployed in the well using the cable. The object
includes a sensor to sense an environment of the object, a
telemetry interface, an actuator, an expandable element and a
control system. The control system uses the sensed environment to
determine a location of the object; uses the telemetry interface to
communicate an indication of the location uphole; uses the actuator
to selectively expand the expandable element to engage a first
valve assembly in response to receiving a first remotely
communicated stimulus; uses the actuator to retract the expandable
element in response to receiving a second remotely communicated
stimulus; and uses the actuator to expand the expandable element to
actuate a second valve assembly in response to receiving a third
remotely communicated stimulus.
[0006] Advantages and other features will become apparent from the
following drawings, description and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a schematic diagram of a multiple stage well
according to an example implementation.
[0008] FIG. 2 is a schematic diagram of a cable-conveyed dart of
FIG. 1 in a radially contracted state according to an example
implementation.
[0009] FIGS. 3A, 3B and 3C are schematic diagrams illustrating use
of the dart in a downhole stimulation operation according to an
example implementation.
[0010] FIG. 4A is a flow diagram depicting a technique to use a
cable-conveyed object in a well according to an example
implementation.
[0011] FIG. 4B is a flow diagram depicting a technique to use a
cable-conveyed activation object to perform a stimulation operation
in a well according to an example implementation.
[0012] FIG. 5 is a schematic diagram of a dart illustrating a
magnetic field sensor of the dart according to an example
implementation.
[0013] FIG. 6A is a schematic diagram of a dart illustrating a
differential pressure sensor of the dart according to an example
implementation.
[0014] FIG. 6B is a flow diagram depicting a technique to determine
the location of a cable-conveyed dart in a well based on a pressure
sensed by the dart according to an example implementation.
[0015] FIG. 7 is a flow diagram depicting a technique to perform a
multiple stage stimulation operation in a well using a
cable-conveyed activation object according to an example
implementation.
[0016] FIG. 8 is a schematic diagram of a dart illustrating an
electromagnetic coupling sensor of the dart according to an example
implementation.
[0017] FIG. 9 is an illustration of a signal generated by the
sensor of FIG. 8 according to an example implementation.
[0018] FIG. 10 is a flow diagram depicting use of an
electromagnetic coupling sensor to sense a position of a
cable-conveyed activation object according to an example
implementation.
[0019] FIG. 11 is a schematic diagram of a dart according to an
example implementation.
DETAILED DESCRIPTION
[0020] In general, systems and techniques are disclosed herein for
purposes of deploying a cable-conveyed activation object into a
well; using the object to sense its location (its location relative
to a downhole, targeted tool assembly to be activated by the
object, for example); communicating the sensed location to the
Earth surface of the well; and based on this communicated position,
controlling the object from the Earth surface to perform one or
more downhole operations. In this context, a "cable-conveyed
object" refers to an object that travels at least some distance in
a well passageway while being attached to a cable-based conveyance
mechanism.
[0021] As specific examples, the cable-based conveyance mechanism
may be a cable that contains one or more electrical communication
lines (called an "electric line" or a "wireline") or a cable that
does not contain any electrical communication lines (called a
"slickline); and the activation object may be a dart, a ball or a
bar that is suspended from the conveyance cable as it is run into
the well, retrieved from the well or in general, has its downhole
location controlled by the conveyance cable. Moreover, in
accordance with some implementations, downhole actions that are
performed by the activation object (such as actions in which the
object radially expands or contract) may be controlled by command
stimuli that are communicated to the object via the cable. In
accordance with some implementations, the movement of the
activation object through a given well passageway may be aided by
pumping (i.e., pushing to object using a fluid), although pumping
may not be employed to move the object in the well, in accordance
with other implementations.
[0022] As just a few examples, the downhole operation may be a
stimulation operation (a fracturing operation or an acidizing
operation, as examples); an operation that is performed by a
downhole tool assembly (the operation of a downhole valve assembly,
the operation of a single shot tool assembly, or the operation of a
perforating gun assembly, as examples); an operation that involves
the formation of a downhole obstruction; or an operation that
diverts fluid (the diversion of fracturing fluid into a surrounding
formation, for example). Moreover, in accordance with example
implementations, a single deployed cable-conveyed activation object
may be used to perform multiple downhole operations in multiple
zones, or stages, of the well, as further disclosed herein.
[0023] In accordance with example implementations, the
cable-conveyed activation object travels in a passageway (a tubing
string passageway, for example) of the well, autonomously senses
its position as it travels in the passageway, and employs uphole
telemetry communication to communicate its sensed position to the
Earth surface. Moreover, in accordance with example
implementations, the cable-conveyed activation object is
constructed to be remotely operated from the Earth surface
initiate/further a given downhole operation.
[0024] As a more specific example, the cable-conveyed activation
object may, in general, have two physical states: a radially
contracted state (i.e., a state in which the object has a
relatively smaller overall outer cross-sectional dimension) and a
radially expanded state (i.e., a state in which the object has a
relatively larger overall cross-sectional dimension). The
cable-conveyed activation object is initially radially contracted
(i.e., has a reduced overall diameter) when the object is deployed
into the well at the Earth surface, and as the conveyance cable is
extended to lower the object into the well, the object continuously
or intermittently communicates indications of its location uphole
to the Earth surface as the object travels downhole. Based on the
object's location, actions may be taken at the Earth surface to
remotely control the state of the object. For example, when the
object reaches a predetermined, targeted location, one or more
actions may be taken at the Earth surface to remotely instruct the
object to radially expand.
[0025] The cable-conveyed object may actuate a downhole tool
assembly, such as a valve assembly, in ways other than radially
expanding the object to engage the assembly. For example, in
accordance with further, example implementations, the object may
form a magnetic coupling with the tool assembly; using a sliding
pin and key arrangement between the object and the assembly; and so
forth.
[0026] The increased diameter of the object due to its radial
expansion may be used to effect any of a number of downhole
actions, such as shifting a valve, forming a fluid obstruction,
actuating a tool, a construction of these actions, and so forth.
Moreover, because the object remains radially contracted before
reaching the predetermined location, the object may pass through
downhole restrictions (valve seats, for example) that may otherwise
"catch" the object, thereby allowing the object to be used in, for
example, multiple stage applications in which the object is used in
conjunction with seats of the same size so that the radial
expansion of the object is used to select which seat catches the
object.
[0027] In accordance with example implementations, the
cable-conveyed activation object is a downhole communication node
of an uphole telemetry system to continuously or intermittently
transmit indications of the object's location to the Earth surface.
For example, in accordance with some implementations, the object
may contain a transmitter (a radio frequency (RF) transmitter, for
example) that is constructed to communicate an electrical signal to
one of more electrical communication lines of a wireline for
purposes of transmitting data uphole, which represents the absolute
or relative location of the object. As a more specific example, the
electrical signal may represent a packet of telemetry data. Other
uphole telemetry techniques may be used, in accordance with
further, example implementations. For example, the object may
contain an acoustic transducer to communicate its position uphole
using acoustic pulses that are communicated via fluid or
communicated along a slickline. As another example, the object may
a tension-based transducer that has arms to selectively contact a
wellbore or tubing string wall for purposes of creating tension
pulses in the conveyance cable, which represents telemetry data
indicative of the object's position. As yet another example, the
object may contain an electromagnetic (EM) wave transducer for
uphole telemetry communication. Thus, many variations are
contemplated, which are within the scope of the appended
claims.
[0028] As disclosed herein, the cable-conveyed activation object
may sense its position based on features of a string in which the
object travels, markers, formation characteristics, and so forth,
depending on the particular implementation. As a more specific
example, for purposes of sensing its downhole location, the
cable-based activation object may be constructed to, during its
travel, sense specific points in the well, called "markers" herein.
Moreover, as disclosed herein, the cable-based activation object
may be constructed to detect the markers by sensing a property of
the environment that surrounds the object (a physical property of
the string in which the object is disposed or a formation, as
examples). The markers may be dedicated tags or materials that are
installed in the well for location sensing by the object or may be
formed from features (sleeve valves, casing valves, casing collars,
and so forth) of the well, which are primarily associated with
downhole functions, other than location sensing. As another
example, the markers may be incorporated into a material that is
used in the construction of the well, such as, for example,
microelectromechanical system (MEMS)-based sensors that are
deployed in a cement slurry. Moreover, as disclosed herein, in
accordance with example implementations, the cable-conveyed
activation object may be constructed to sense its location in other
and/or different ways that do not involve sensing a physical
property of its environment, such as, for example, sensing a
pressure for purposes of identifying valves or other downhole
features that the object traverses and/or passes in the vicinity of
during its travel.
[0029] In accordance with further example implementations,
activation of the object may be based on the measurement of a
length, such as measurement of a length between certain features of
the tubing string 130.
[0030] Referring to FIG. 1, as a more specific example of the
object and its well environment, in accordance with some
implementations, a multiple stage well 90 includes a wellbore 120,
which traverses one or more formations (hydrocarbon bearing
formations, for example). As a more specific example, the wellbore
120 may be lined, or supported, by a tubing string 130, as depicted
in FIG. 1. The tubing string 130 may be cemented to the wellbore
120 (such wellbores typically are referred to as "cased hole"
wellbores); or the tubing string 130 may be secured to the
formation by packers (such wellbores typically are referred to as
"open hole" wellbores). In general, the wellbore 120 extends
through one or multiple zones, or stages 170 (four stages 170-1,
170-2, 170-3 and 170-4, being depicted as examples in FIG. 1).
[0031] It is noted that although FIG. 1 depicts a laterally
extending wellbore 120, the systems and techniques that are
disclosed herein may likewise be applied to vertical wellbores,
such as the example vertical wellbores that are illustrated in
FIGS. 3A, 3B and 3C and discussed below. In accordance with example
implementations, the well may contain multiple wellbores, which
contain tubing strings that are similar to the illustrated tubing
string 130. Moreover, depending on the particular implementation,
the well may be an injection well or a production well. Thus, many
variations are contemplated, which are within the scope of the
appended claims.
[0032] In general, the downhole operations that are performed using
the cable-conveyed activation object may be multiple stage
operations that may be sequentially performed in the stages 170 in
a particular direction (in a direction from a toe end 182 of the
wellbore 120 to a heel end 180 of the wellbore 120 or vice versa,
as examples) or may be performed in no particular direction or
sequence, depending on the implementation.
[0033] Although not depicted in FIG. 1, fluid communication with
the surrounding reservoir may be enhanced in one or more of the
stages 170 through, for example, abrasive jetting operations,
perforating operations, and so forth.
[0034] In accordance with example implementations, the well of FIG.
1 includes downhole tool assemblies 152 (tool assemblies 152-1,
152-2, 152-3, 152-4 and 152-5, being depicted in FIG. 1 as
examples) that are located in the respective stages 170. The tool
assembly 152 may be any of a variety of downhole tool assemblies,
such as a valve assembly (a circulation valve assembly, a casing
valve assembly, a sleeve valve assembly, and so forth), a seat
assembly, a check valve assembly, a plug assembly, a perforation
gun assembly, and so forth, depending on the particular
implementation. Moreover, the tool assembly 152 may contain
different tools (a mixture of a casing valve assembly, a plug
assembly, a check valve assembly, and so forth, for example).
[0035] A given tool assembly 152 may be selectively actuated by
deploying the cable-conveyed activation object through the central
passageway of the tubing string 130 and activating the object so
that the object enters a state that is used to actuate the tool
assembly 152. As an example, the general cross-dimensional size of
the object may be expanded to actuate a given tool assembly 152.
For these example implementations, the cable-based activation
object, when in its radially contracted state, passes relatively
freely through the central passageway of the tubing string 130 (and
thus, through tool assemblies of the string 130), and when in its
radially expanded state, the object is configured to land in, or,
be "caught" by, a selected one of the tool assemblies 152 or
otherwise secured at a selected downhole location (in general), for
purposes of performing a given downhole operation. For example, a
given downhole tool assembly 152 may catch the cable-conveyed
activation object in its radially expanded state and for purposes
of forming a downhole fluid obstruction, or barrier in the tubing
string 130. The tubing string 130 uphole of the fluid barrier may
then be pressurized to actuate the tool assembly 152.
[0036] For the specific example of FIG. 1, the cable-conveyed
activation object is a dart 100, which, as depicted in FIG. 1, may
be deployed from the Earth surface E into the tubing string 130 at
the end of a conveyance cable 101 and propagate along the central
passageway of the string 130 as the dart 100 is lowered into the
well by the cable 101. Based on the indications of the dart's
position that are communicated by the dart 100 uphole,
corresponding actions may be taken at the Earth surface E to
control the dart's downhole state. For example, commands may be
communicated downhole (via the cable 101, via acoustic signals,
electromagnetic signals, conveyance line movement and so forth) for
purposes of instructing the dart 100 to radially expand and engage
the next tool assembly 152 that the dart 100 encounters.
[0037] In accordance with an example implementation, the dart 100
may sequentially engage the tool assemblies 152 of the stages
170-4, 170-3, 170-2 and 170-1 in that order. For this example, the
dart 100 may be deployed on the cable 100 into the central
passageway of the tubing string 130 from the Earth surface E, and
the cable 100 is used to lower the dart 100 downhole. When the dart
100 is in proximity of the tool assembly 152 of the stage 170-4 (as
indicated by the uphole telemetry information that is communication
by the dart 100), an operator at the Earth surface E takes action
to cause the dart 100 to radially expand so that the dart 100
engages a dart catching seat of the tool assembly 152-4. Using the
resulting fluid obstruction, or barrier, that is created by the
dart 100 landing in the tool assembly 152-4, fluid pressure may be
applied uphole of the dart 100 (by pumping fluid into the tubing
string 130, for example) for purposes of actuating the tool
assembly 152-4.
[0038] The dart 100 is constructed to subsequently radially
contract to release itself from the tool assembly 152-4 (as further
disclosed herein), be pulled uphole via the cable 101, and be
controlled to radially expand inside of the tool assembly 152-3 of
the stage 170-3 to create another fluid barrier. Using this fluid
barrier, the portion of the tubing string 130 uphole of the dart
100 may be pressurized for purposes of actuating the tool assembly
152-3. The above-described process may then be repeated for the
tool assemblies 152 in stages 170-2 and 170-1.
[0039] Although examples are disclosed herein in which the dart 100
may be controlled to radially expand inside a tool assembly, in
accordance with further example implementations, the dart 100 is
constructed to secure itself to an arbitrary position of the string
130, which is not part of a tool assembly. Thus, many variations
are contemplated, which are within the scope of the appended
claims.
[0040] For the specific example of FIG. 1, the dart 100 senses its
downhole location by sensing downhole markers 160. For example, as
depicted in FIG. 1, each stage 170 may contain a marker 160, and
each marker 160 may be embedded in a different tool assembly 152.
The marker 160 may be a specific material, a specific downhole
feature, a specific physical property, a radio frequency (RF)
identification (RFID), tag, and so forth, depending on the
particular implementation.
[0041] It is noted that each stage 170 may contain multiple markers
160; a given stage 170 may not contain any markers 160; the markers
160 may be deployed along the tubing string 130 at positions that
do not coincide with given tool assemblies 152; the markers 160 may
not be evenly/regularly distributed as depicted in FIG. 1; and so
forth, depending on the particular implementation. Moreover,
although FIG. 1 depicts the markers 160 as being deployed in the
tool assemblies 152, the markers 160 may be deployed at defined
distances with respect to the tool assemblies 152, depending on the
particular implementation. For example, the markers 160 may be
deployed between or at intermediate positions between respective
tool assemblies 152, in accordance with further implementations.
Thus, many variations are contemplated, which are within the scope
of the appended claims.
[0042] In accordance with an example implementation, a given marker
160 may be a magnetic material-based marker, which may be formed,
for example, by a ferromagnetic material that is embedded in or
attached to the tubing string 130, embedded in or attached to a
given tool housing, and so forth. By sensing the markers 160, the
dart 100 may determine its absolute or relatively downhole location
and use uphole telemetry to communicate that position to the Earth
surface E. In this manner, the dart 100 may count the markers 160,
determine its location based on the count and communicate, via
uphole telemetry, the location to the Earth surface E. In further
implementations, the dart 100 may sense the markers 160 and
transmit an indication of a sensed marker 160 uphole to the Earth
surface E every time a marker 160 is sensed, so that a human or
electronics at the Earth surface E may count the markers to
determine the dart's location.
[0043] The dart 100 may, in accordance with example
implementations, detect specific markers 160, while ignoring other
markers 160. In this manner, another dart may be subsequently
deployed into the tubing string 130 to count the previously-ignored
markers 160 (or count all of the markers, including the ignored
markers, as another example) in a subsequent operation, such as a
remedial action operation, a fracturing operation, and so forth. In
this manner, using such an approach, specific portions of the well
may be selectively treated at different times. In accordance with
some example implementations, the tubing string 130 may have more
tool assemblies 152 (see FIG. 1), such as sleeve valve assemblies
(as an example), than are needed for current downhole operations,
for purposes of allowing future refracturing or remedial operations
to be performed.
[0044] As a more specific example, the dart 100 may be deployed on
the cable 101 for purposes of performing a being caught in the tool
assembly 152-4, which, for this example, has there tool assemblies
152-1, 152-2 and 153 that are location uphole of the assembly
152-4. Therefore, after the dart 100 has passed by three markers
160 (i.e., the markers 160 of the tool assemblies 152-1, 152-2 and
152-3), the Earth surface E has received an indication that the
dart 100 is between the tool assemblies 152-3 and 152-4. At this
point, the dart 100 may be remotely controlled from the Earth
surface to cause the dart 100 to radially expand so that when the
cable 101 further lowers the dart 100 downhole, the dart 100
engages the tool assembly 152-4.
[0045] Referring to FIG. 2, in accordance with an example
implementation, the dart 100 has one or multiple, outer elastomer
rings 252, which are constructed to radially expand (be compressed
between opposing pistons, or thimbles 254 and 256, for example) for
purposes of radially expanding the dart 100 to lodge the dart 100
inside a given sleeve valve assembly. In this manner, when deployed
into the well, in accordance with example implementations, the
thimbles 254 and 256 are spaced apart to allow the elastomer
element(s) 252 to relax to reduce the outer diameter of the dart
100 to a sufficiently small diameter to allow the dart 100 to pass
through other passageways, valve assemblies, and so forth.
[0046] As depicted in FIG. 2, in accordance with an example
implementation, the dart 100 includes a controller 224 (a
microcontroller, microprocessor, field programmable gate array
(FPGA), or central processing unit (CPU), as examples), which is
constructed to communicate with a telemetry interface 250 of the
dart 100 for purposes of communicating sensed dart positions to the
Earth surface E, receive data indicative of commands for the dart
100 (commands to radially expand and retract, as examples), and so
forth. In accordance with example implementations, the controller
224 may include a memory (a volatile or a non-volatile memory,
depending on the implementation) that stores program instructions
and data for the controller 224.
[0047] In accordance with example implementations, the telemetry
interface 250 may include a transceiver (RF transceiver, acoustic
transceiver, and so forth) for purposes of communicating data to
(uphole telemetry) the Earth surface and for purposes of
communicating data and commands from (downhole telemetry) from the
Earth surface. The uphole and/or downhole telemetry may involve the
use of the cable 101, in accordance with example implementations.
For example, the uphole/downhole telemetry may use one or more
wires, fibers, and so forth of the cable 101. Moreover, in
accordance with some example implementations, the telemetry
interface 250 may control arms (not shown) that selectively contact
the wellbore or tubing string wall for purposes of communicating
data with the Earth surface via tension pulses. The telemetry
interface 250 may also use, in accordance with further example
implementations, acoustic signals, electromagnetic (EM) signals,
acoustic pulses, fluid pulses, and so forth for uphole and/or
downhole communications, depending on the particular
implementation. Thus, the telemetry interface 250 may, for example,
communicate stimuli uphole to indicate the dart's downhole
position; and the telemetry interface 250 may receive stimuli
communicated downhole for such purposes as directing the dart 100
to operate in a manner to engage a downhole tool assembly (such as
a valve assembly), disengage from a given downhole tool assembly to
allow the dart 100 to travel to other downhole positions, engage
another downhole tool assembly, and so forth.
[0048] FIG. 2 also depicts an actuator 220 that is coupled to the
controller 224 for purposes of controlling the radial expansion and
contraction of the dart 100. In this regard, in accordance with
some example implementations, the controller 224 controls the
actuator 220 for purposes of compressing the thimbles 254 and 256
for purposes of radially expanding the resilient element 252 as
well as radially expanding one or multiple slips 260 of the dart
100. In this regard, engagement of the slips 260 with a tubing
string wall, sleeve valve, and so forth, stops downhole progress of
the dart 100 and anchors the dart 100 to the surrounding
member.
[0049] Among its other components, the dart 100 may have a downhole
energy source, in accordance with further example implementations,
such as a battery or a fuel cell, and in accordance with further
example implementations, the dart 100 may receive its power from
the cable 101 (for the case of a wireline, for example). Moreover,
as shown in FIG. 2, in accordance with example implementations, the
dart 100 may have a wiper 264 at its lower end for purposes of
allowing the pumping of fluid to facilitate the movement of the
dart 100 through the well. In further implementations, the dart may
have power regulation circuitry that receives power either from the
cable 100 or a downhole energy source and distributes regulated
supply voltages to the electrical power consuming components of the
dart 100.
[0050] As also depicted in FIG. 2, in accordance with example
implementations, the dart 100 includes at least one sensor 230. In
general, the sensor 230 may be used to detect markers 160 as well
as detect other downhole features for purposes of acquiring an
indication of the dart's downhole position, as further disclosed
herein.
[0051] In accordance with example implementations, the sensor 230
provides one or more signals that indicate a physical property of
the dart's environment (a magnetic permeability of the tubing
string 130, a radioactivity emission of the surrounding formation,
and so forth); the controller 224 use the signal(s) to determine a
location of the dart 100; and the controller 224 correspondingly
uses the telemetry interface 250 to communicate with the Earth
surface E for purposes of informing an operator or circuitry at the
Earth surface E as to the dart's location.
[0052] In accordance with example implementations, the sensor 230
senses a magnetic field. In this manner, the tubing string 130 may
contain embedded magnets, and sensor 230 may be an active or
passive magnetic field sensor that provides one or more signals,
which the controller 224 interprets to detect the magnets. However,
in accordance with further implementations, the sensor 230 may
sense an electromagnetic coupling path for purposes of allowing the
dart 100 to electromagnetic coupling changes due to changing
geometrical features of the string 130 (thicker metallic sections
due to tools versus thinner metallic sections for regions of the
string 130 where tools are not located, for example) that are not
attributable to magnets. In other example implementations, the
sensor 230 may be a gamma ray sensor that senses a radioactivity.
Moreover, the sensed radioactivity may be the radioactivity of the
surrounding formation. In this manner, a gamma ray log may be used
to program a corresponding location radioactivity-based map into a
memory of the dart 100.
[0053] FIGS. 3A, 3B and 3C depicts deployment and use of the dart
100 in a multiple stage fracturing operation in a vertical wellbore
that contains sleeve valve assemblies 300 and markers 160. For this
example, the dart 100 is used to perform a fracturing operation in
stage 170-3; and as shown in FIG. 3A, initially all of the sleeve
valve assemblies 300 are closed so that radial fluid communication
with the surrounding formations is prevented. The dart 100 is
deployed into the tubing string 130 on the cable 101 and passes
through valve assemblies 170-1 and 170-2. For this example
implementation, the valve assembly 300 in the stage 170-3 contains
a marker 160 that identifies the valve assembly 170-3 as being the
valve assembly 300 that is targeted by the dart 100.
[0054] Referring to FIG. 3B, the dart's proximity to the stage
170-3 (and its associated marker 160) is detected at the Earth
surface using the uphole telemetry communication from the dart 100.
At this point, the dart 100 is remotely controlled from the Earth
surface E to cause the dart 100 to radially expand above the valve
assembly 300 of the stage 170-3 so that as the dart 100 is further
deployed downhole, the dart 100 lodges in an inner sleeve 304 of
the valve assembly 300, in shown in FIG. 3B. The lodging of the
dart 100 in the inner sleeve 300 creates a fluid barrier in the
tubing string 130. Referring to FIG. 3C, therefore upon application
of hydraulic pressure above the barrier (by pumping fluid downhole
into the central passageway of the tubing string 130), a downward
shifting force is developed to shift the inner sleeve 304
downwardly to open radial fluid communication through the valve
assembly's radial ports 302. At this point, fracturing fluid may be
pumped downhole in the tubing string 130, and the fluid is diverted
by the fluid barrier through the radial ports 302 and into the
surrounding formation.
[0055] Continuing the example, the dart 100 may then be remotely
controlled from the Earth surface to cause the dart 100 to radially
contract at the conclusion of the fracturing of the zone associated
with the stage 170-3. Once radially contracted, as an example, the
cable 101 may be used to move the dart 100 uphole of the valve
assembly 300 for the stage 170-2. For example, in accordance with
some implementations, the cable 101 may be retracted to cause the
dart 100 to pass through a marker (not shown) associated with the
valve assembly 300 for the stage 170-2. Upon receiving an
indication of this position of the dart 100, a command may then be
communicated downhole to once again cause the dart 100 to radially
expand. Next, the dart 100 may be lowered downhole to thereafter
engage the inner sleeve 304 of the valve assembly for the stage
170-2. At this point, the radially expanded dart 100, now engaged
with the inner sleeve 304, may be forced farther downhole using
hydraulic pressure to shift the valve assembly 300 open. Once
again, fluid may then be communicated using the fluid barrier
created by the dart 100 and the open state of the valve assembly
300 for purposes of fracturing the associated zone. Other zones may
be fractured using the above-described process.
[0056] Although the above-described multiple stage operation occurs
in an uphole direction, it is understood that the dart 100 may be
used for purposes of performing multiple stage operations in a
downhole direction, in accordance with further, example
implementations. For these implementations, the dart 100 may, while
in the radially expanded state, be pulled uphole to subsequently
reclose the valve assembly 300 before the dart 100 is radially
contracted to allow the dart 100 to move to the next valve assembly
300.
[0057] Thus, in general, a technique 400 that is depicted in FIG.
4A includes deploying (block 402) a cable-conveyed object in a
passageway of a string in a well and using (block 404) the object
to sense a property of an environment of the string and communicate
an indication of the sensed property to the Earth surface of the
well. Pursuant to the technique 400, the object may be remotely
controlled (block 406) based on the communicated indication to
engage a downhole valve assembly and transition the assembly from
one state (a closed state, for example) to another state (an open
state, for example). The object may then be used to perform (block
408) a downhole operation.
[0058] For example, in accordance with some implementations, the
object may be radially expanded to engage a sleeve of a valve
assembly and shift the sleeve to open the valve assembly. Due to
the fluid barrier, or obstruction, that is created by the now
lodged object, fluid may be diverted into the surrounding formation
through radial ports of the opened valve assembly to conduct a
downhole operation, such as a stimulation operation (a fracturing
operation, as a more specific example). The technique 400 further
includes allowing (block 410) the object to travel to the next
downhole valve assembly and repeating blocks 404, 406 and 408 at
least one additional time. In this regard, the object may be
released by radially contracting the object (or by operating
another type of release mechanism of the object) to allow the
object to move to change the state of another downhole valve
assembly and perform another stimulation operation in a similar
manner.
[0059] A technique 420 that is depicted in FIG. 4B may be used for
purposes of performing a stimulation operation in a well. Referring
to FIG. 4B, pursuant to the technique 420, in a well, a
cable-conveyed object is deployed in a passageway of a string,
pursuant to block 422. The object is used (block 424) to sense a
downhole location of the object and communicate an indication of
the sensed location of the Earth surface of the well, pursuant to
block 424. In response to this indication, operation of the object
may be remotely controlled from the Earth surface to cause the
object to radially expand in a given valve assembly, pursuant to
block 426. A fluid barrier that is created by the radial expansion
of the object is then used (block 426) to hydraulically shift the
given valve assembly open so that a stimulation operation may be
performed (block 430) in the zone that is associated with the given
valve assembly.
[0060] Referring to FIG. 5 in conjunction with FIG. 2, in
accordance with an example implementation, the sensor 230 of the
dart 100 may include a coil 504 for purposes of sensing a magnetic
field. In this manner, the coil 504 may be formed from an
electrical conductor that has multiple windings about a central
opening. When the dart passes in proximity to a ferromagnetic
material 520, such as a magnetic marker 160 that contains the
material 520, magnetic flux lines 510 of the material 520 pass
through the coil 504. Thus, the magnetic field that is sensed by
the coil 504 changes in strength due to the motion of the dart 100
(i.e., the influence of the material 520 on the sensed magnetic
field changes as the dart 100 approaches the material 520,
coincides in location with the material 520 and then moves past the
material 520). The changing magnetic field, in turn, induces a
current in the coil 504. The controller 224 (see FIG. 2) may
therefore monitor the voltage across the coil 504 and/or the
current in the coil 504 for purposes of detecting a given marker
160; and thereafter, the controller 224 may use the telemetry
interface 250 for purposes of communicating to the Earth surface a
detected position of the dart 100. The coil 504 may or may not be
pre-energized with a current (i.e., the coil 504 may passively or
actively sense the magnetic field), depending on the particular
implementation.
[0061] It is noted that FIGS. 2 and 5 depict a simplified view of
the sensor 230 and controller 224, as the skilled artisan would
appreciate that numerous other components may be used, such as an
analog-to-digital converter (ADC) to convert an analog signal from
the coil 504 into a corresponding digital value, an analog
amplifier, and so forth, depending on the particular
implementation.
[0062] In accordance with example implementations, the dart 100 may
sense a pressure to detect features of the tubing string 130 for
purposes of determining the location/downhole position of the dart
100. For example, referring to FIG. 6A, in accordance with example
implementations, the dart 100 includes a differential pressure
sensor 620 that senses a pressure in a passageway 610 that is in
communication with a region 660 uphole from the dart 100 and a
passageway 614 that is in communication with a region 670 downhole
of the dart 100. Due to this arrangement, the partial fluid
seal/obstruction that is introduced by the dart 100 in its radially
contracted state creates a pressure difference between the upstream
and downstream ends of the dart 100 when the dart 100 passes
through a valve assembly.
[0063] For example, as shown in FIG. 6A, a given valve may contain
radial ports 604. Therefore, for this example, the differential
pressure sensor 620 may sense a pressure difference as the dart 100
travels due to a lower pressure below the dart 100 as compared to
above the dart 100 due to a difference in pressure between the
hydrostatic fluid above the dart 100 and the reduced pressure (due
to the ports 604) below the dart 100. As depicted in FIG. 6A, the
differential pressure sensor 620 may contain terminals 624 that,
for example, electrically indicate the sensed differential pressure
(provide a voltage representing the sensed pressure, for example),
which may be communicated to the controller 224 (see FIG. 2). For
these example implementations, valves of the tubing string 130 are
effectively used as markers for purposes of allowing the dart 100
to sense its position along the tubing string 130.
[0064] Therefore, in accordance with example implementations, a
technique 680 that is depicted in FIG. 6B may be used in
conjunction with the dart 100. Pursuant to the technique 680,
cable-conveyed object is deployed (block 682) in a passageway of a
string; and the object is used (block 684) to sense pressure as the
object travels in a passageway of the string. The technique 680
includes selectively communicating (block 686) with the Earth
surface to indicate detection of a valve assembly based at least in
part on the sensed pressure.
[0065] In accordance with some implementations, the dart 100 may
sense multiple indicators of its position as the dart 100 travels
in the tubing string 130. For example, in accordance with example
implementations, the dart 100 may sense both a physical property
and another downhole position indicator, such as a pressure (or
another property), for purposes of determining its downhole
position. Moreover, in accordance with some implementations, the
markers 160 (see FIG. 1) may have alternating polarities, which may
be another position indicator that the dart 100 uses to
assess/corroborate its downhole position. In this regard,
magnetic-based markers 160, in accordance with an example
implementation, may be distributed and oriented in a fashion such
that the polarities of adjacent magnets alternate. Thus, for
example, one marker 160 may have its north pole uphole from its
south pole, whereas the next marker 160 may have its south pole
uphole from its north pole; and the next the marker 160 may have
its north pole uphole from its south pole; and so forth. The dart
100 may use the knowledge of the alternating polarities as feedback
to verify/assess its downhole position.
[0066] Thus, referring to FIG. 7, in accordance with an example
implementation, a technique 700 for autonomously operating an
untethered object in a well, such as the dart 100, includes
determining (decision block 704) whether a marker has been
detected. If so, the dart 100 updates a detected marker count and
updates its location and transmits an indication of its location
uphole to the Earth surface, pursuant to block 708. The dart 100
further determines (block 712) its location based on a sensed
marker polarity pattern, and the dart 100 may determine (block 716)
its location based on one or more other measures (a sensed
pressure, for example). If the dart 100 determines (decision block
720) that the marker count is inconsistent with the other
determined locations, then the dart 100 adjusts (block 724) the
marker count/location.
[0067] In accordance with example implementations, the dart 100
continually performs the above-described loop (sensing and
transmitting its location uphole); and the radial expansion and
contraction of the dart 100 are independently controlled. In
further example implementations, when the dart 100 determines
(decision block 728) that the dart 100 has received a command to
expand, the dart 100 suspends the location transmission and
performs functions related to expanding and contracting, as
controlled from the Earth surface. In this manner, in accordance
with example implementations, the dart 100 actuates (block 733) its
actuator to cause the radial expansion of the dart 100 and
thereafter waits (decision block 736) for a command to release the
dart 100. In this regard, in accordance with example
implementations, upon receiving a command to be released, the dart
activates (block 740) a self-release mechanism to release the dart.
For example, in accordance with some implementations, the dart 100
actuates the actuator in the opposite direction used to expand the
dart for purposes of radially contracting the dart to allow the
dart to be moved to the next valve assembly, be moved to another
position in the well, and so forth. In accordance with example
implementations, if the dart is to be radially expanded again
(decision block 744), then control returns to decision block
704.
[0068] Other variations are contemplated, which are within the
scope of the appended claims. For example, FIG. 8 depicts a dart
800 according to a further example implementation. In general, the
dart 800 includes an electromagnetic coupling sensor that is formed
from two receiver coils 814 and 816, and a transmitter coil 810
that resides between the receiver coils 815 and 816. As shown in
FIG. 8, the receiver coils 814 and 816 have respective magnetic
moments 815 and 817, respectively, which are opposite in direction.
It is noted that the moments 815 and 817 that are depicted in FIG.
8 may be reversed, in accordance with further implementations. As
also shown in FIG. 8, the transmitter 810 has an associated
magnetic moment 811, which is pointed upwardly in FIG. 8, but may
be pointed downwardly, in accordance with further
implementations.
[0069] In general, the electromagnetic coupling sensor of the dart
800 senses geometric changes in a tubing string 804 in which the
dart 800 travels. More specifically, in accordance with some
implementations, the controller (not shown in FIG. 8) of the dart
800 algebraically adds, or combines, the signals from the two
receiver coils 814 and 816, such that when both receiver coils 814
and 816 have the same effective electromagnetic coupling the
signals are the same, thereby resulting in a net zero voltage
signal. However, when the electromagnetic coupling sensor passes by
a geometrically varying feature of the tubing string 804 (a
geometric discontinuity or a geometric dimension change, such as a
wall thickness change, for example), the signals provided by the
two receiver coils 814 and 816 differ. This difference, in turn,
produces a non-zero voltage signal, thereby indicating to the
controller that a geometric feature change of the tubing string 804
has been detected.
[0070] Such geometric variations may be used, in accordance with
example implementations, for purposes of detecting certain
geometric features of the tubing string 804, such as, for example,
sleeves or sleeve valves of the tubing string 804. Thus, by
detecting and possibly counting sleeves (or other tools or
features), the dart 800 may determine its downhole position and
actuate its deployment mechanism accordingly.
[0071] Referring to FIG. 9 in conjunction with FIG. 8, as a more
specific example, an example signal is depicted in FIG. 9
illustrating a signature 902 of the combined signal (called the
"V.sub.DIFF" signal in FIG. 9) when the electromagnetic coupling
sensor passes in proximity to an illustrated geometric feature 820,
such as an annular notch for this example.
[0072] Thus, referring to FIG. 10, in accordance with example
implementations, a technique 1000 includes deploying (block 1002) a
cable-conveyed object in a string and using (block 1004) the object
to sense an electromagnetic coupling as the object travels in a
passageway of the string. The technique 1000 includes selectively
communicating (block 1006) with the Earth surface to indicate
detection of a valve assembly based at least in part on the sensed
electromagnetic coupling.
[0073] Thus, in general, implementations are disclosed herein for
purposes of deploying a cable-conveyed object through a passageway
of the string in a well and using the object to sense a location
indicator as the object traverses the passageway. The object
communicates an indication of its position to the Earth surface and
is constructed to be remotely actuated from the Earth surface to
selectively expand and retract. As disclosed above, the property
may be a physical property such as a magnetic marker, an
electromagnetic coupling, a geometric discontinuity, a pressure or
a radioactive source. In further implementations, the physical
property may be a chemical property or may be an acoustic wave.
Moreover, in accordance with some implementations, the physical
property may be a conductivity. In yet further implementations, a
given position indicator may be formed from an intentionally-placed
marker, a response marker, a radioactive source, magnet,
microelectromechanical system (MEMS), a pressure, and so forth. The
cable-conveyed activation object has the appropriate sensor(s) to
detect the locations indicator(s), as can be appreciated by the
skilled artisan in view of the disclosure contained herein.
[0074] Other implementations are contemplated and are within the
scope of the appended claims. For example, in accordance with
further example implementations, the dart may have a container that
contains a chemical (a tracer, for example) that is carried into
the fractures with the fracturing fluid. In this manner, when the
dart is deployed into the well, the chemical is confined to the
container. The dart may contain a rupture disc (as an example), or
other such device, which is sensitive to the tubing string pressure
such that the disc ruptures at fracturing pressures to allow the
chemical to leave the container and be transported into the
fractures. The use of the chemical in this manner allows the
recovery of information during flowback regarding fracture
efficiency, fracture locations, and so forth.
[0075] As another example of a further implementation, the
telemetry interface 250 (see FIG. 2) of the dart 100 may be used
for purposes of communicating information other than the
above-described commands and locations. For example, in accordance
with further example implementations, the telemetry interface 250
may be used by the controller 224 (see FIG. 2) for purposes of
communicating a status of the dart to the Earth surface. For
example, the status may be an acknowledgment that the dart 100 has
expanded, contracted, and so forth. As another example, the status
may be a status indicating whether dart 100 is functioning
properly. Other information may be communicated using the telemetry
interface 250, such as sensed downhole pressures, temperatures and
so forth.
[0076] As yet another example, in accordance with some
implementations, the cable-conveyed object may contain or be
attached to a perforating gun assembly. In this regard, FIG. 11
depicts a cable-conveyed object 1100 in accordance with a further
example implementation. For this example, the object 1100 includes
a perforating gun assembly 1102. As an example, a firing head of
the perforating gun assembly 1102 may be instructed to fire
perforating charges (shaped charges, for example) of the assembly
1102 by remotely communicating stimuli to the assembly 1102 from
equipment at the Earth surface of the well. For example, after the
cable-conveyed object 1100 forms a fluid obstruction, pressure
pulses may be communicated to the firing head using the fluid
column above the object 1100. In further example implementations,
the cable 101 may be moved in a predetermined pattern to send a
firing command to the perforating gun assembly 1102. In yet further
example implementations, pressure in the fluid column above the
object 1100 (due to the object 1100 creating a fluid obstruction)
may be used to cause the firing head to fire the perforating
charges. Other stimuli (acoustic, electromagnetic (EM), electrical,
and so forth) may be used to communicate with the firing head and
with the object 1100 in general, in accordance with further example
implementations.
[0077] Thus, in accordance with example implementations, the
cable-conveyed object 1100 may be used to perforate a given zone,
or stage of a well and then perform a stimulation operation in the
stage before moving onto to the next stage where another set of
stimulation and perforation operations are performed. Thus, the
perforation and stimulation may be repeated for multiple zones. In
further example implementations, the perforating gun assembly 1102
may be replaced with another type of perforating tool, such as an
abrasive fluid-based jetting tool, for example.
[0078] While a limited number of examples have been disclosed
herein, those skilled in the art, having the benefit of this
disclosure, will appreciate numerous modifications and variations
therefrom. It is intended that the appended claims cover all such
modifications and variations.
* * * * *