U.S. patent application number 13/211515 was filed with the patent office on 2013-02-21 for systems and methods for selective electrical isolation of downhole tools.
The applicant listed for this patent is Joseph C. Joseph. Invention is credited to Joseph C. Joseph.
Application Number | 20130043048 13/211515 |
Document ID | / |
Family ID | 47711816 |
Filed Date | 2013-02-21 |
United States Patent
Application |
20130043048 |
Kind Code |
A1 |
Joseph; Joseph C. |
February 21, 2013 |
Systems and Methods for Selective Electrical Isolation of Downhole
Tools
Abstract
Systems and methods for electrically isolating selected ones of
a set of downhole tools that are connected to a common electrical
cable. In one embodiment, a system includes surface equipment, a
plurality of downhole tools and a common electrical cable. The
downhole tools are connected to the cable by coupling switches.
Each switch has a closed position in which the downhole tool is
electrically coupled to the cable and an open position in which the
downhole tool is electrically decoupled from the cable. The
coupling switches are remotely actuated by placing an actuating
device in proximity to the switches, thereby alternately coupling
the corresponding downhole tools to the common cable or isolating
the tools from the cable.
Inventors: |
Joseph; Joseph C.; (Houston,
TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Joseph; Joseph C. |
Houston |
TX |
US |
|
|
Family ID: |
47711816 |
Appl. No.: |
13/211515 |
Filed: |
August 17, 2011 |
Current U.S.
Class: |
166/381 ;
166/65.1 |
Current CPC
Class: |
E21B 43/128 20130101;
E21B 47/12 20130101; E21B 17/028 20130101; E21B 47/092
20200501 |
Class at
Publication: |
166/381 ;
166/65.1 |
International
Class: |
E21B 23/00 20060101
E21B023/00; E21B 43/00 20060101 E21B043/00 |
Claims
1. A system comprising: surface equipment positioned at the surface
of a well; a cable coupled to the surface equipment, wherein the
cable extends into a wellbore of the well; and a plurality of
downhole tools, wherein at least a first one of the downhole tools
is connected to the cable by a switch, wherein the switch has a
closed position in which the downhole tool is electrically coupled
to the cable and an open position in which the downhole tool is
electrically decoupled from the cable, wherein the switch is
configured to be actuated to move between the open and closed
positions while the first one of the downhole tools is positioned
downhole in the wellbore.
2. The system of claim 1, wherein the first one of the downhole
tools is configured to be selectively coupled to or decoupled from
the cable independently of other ones of the plurality of downhole
tools.
3. The system of claim 1, wherein the first one of the downhole
tools comprises a sensor.
4. The system of claim 1, wherein the first one of the downhole
tools comprises a control device.
5. The system of claim 1, wherein the switch is configured to be
actuated by a magnet which is positioned in close proximity to the
switch.
6. The system of claim 1, wherein the cable comprises a conductor
which is configured to provide power to ones of the plurality of
downhole tools that are coupled to the cable.
7. The system of claim 6, wherein the cable is further configured
to carry data to or from ones of the plurality of downhole tools
that are coupled to the cable.
8. The system of claim 1, wherein the cable comprises a conductor
which is configured to carry data to or from ones of the plurality
of downhole tools that are coupled to the cable.
9. The system of claim 1, wherein the first one of the downhole
tools further comprises a fuse connected between the downhole tool
and the cable.
10. An apparatus comprising: a downhole tool having one or more
electrical components that are configured to be coupled to a
conductor external to the downhole tool; a coupling configured to
be coupled to the conductor external to the downhole tool; and a
switch connected between the electronic components and the
coupling; wherein when the switch is in a closed position the
electronic components are electrically connected to the coupling,
and wherein when the switch is in an open position the electronic
components are electrically isolated from the coupling; and wherein
the switch is configured to be actuated by an actuating device
which is external to the downhole tool.
11. The apparatus of claim 10, wherein the downhole tool comprises
a sensor.
12. The apparatus of claim 10, wherein the downhole tool comprises
a control device.
13. The apparatus of claim 10, further comprising a fuse coupled
between the one or more electrical components and the switch.
14. A method comprising: positioning a plurality of downhole tools
within a wellbore of a well, wherein each of the plurality of
downhole tools is connected to a common cable via a corresponding
switch; positioning an actuating device in close proximity to a
first one of the downhole tools; and actuating the switch coupled
between the first one of the downhole tools and the common cable,
thereby moving the switch between a closed position in which the
downhole tool is electrically coupled to the cable and an open
position in which the downhole tool is electrically isolated from
the cable.
15. The method of claim 14, wherein the switch coupled between the
first one of the downhole tools and the common cable is actuated
independently of switches connected to other ones of the downhole
tools.
16. The method of claim 14, wherein actuating the switch coupled
between the first one of the downhole tools and the common cable
comprises positioning a magnet in close proximity to the
switch.
17. The method of claim 14, further comprising detecting a
malfunction associated with the first one of the downhole tools,
wherein the switch coupled between the first one of the downhole
tools and the common cable is actuated in response to detecting the
malfunction.
Description
BACKGROUND
[0001] 1. Field of the Invention
[0002] The invention relates generally to oil production, and more
particularly to systems and methods for selectively coupling or
decoupling individual downhole tools from a common electrical line
connects the downhole tools to equipment at the surface of a
well.
[0003] 2. Related Art
[0004] Petroleum drilling and production operations typically
involve the collection and processing of large amounts of data and
the adjustment of production equipment based on the processed data.
Various different tools may be installed in wells to collect the
necessary information and to control well operations. For instance,
gauges may be installed downhole to sense well conditions such as
temperature, pressure, flow rate, etc. Control devices such as
valves and packers may be installed downhole to regulate the
production of oil from the wells.
[0005] Often, multiple downhole tools are connected to a single
electrical cable that extends from the surface of the well, through
the wellbore to each of the tools. There may, for instance, be 8-16
tools connected to a single cable. Normally, when the downhole
tools are deployed in the well, the installation is considered to
be permanent, and the tools are expected to remain in place for the
life of the well, which may be 5-10 years or more.
[0006] One of the problems that may arise when multiple downhole
tools are connected to a single cable is that the failure of one
tool may adversely affect the other tools. For instance, if one of
the downhole tools experiences a short circuit, the entire cable
may be shorted as well, preventing the use of the remainder of the
tools that are connected to the cable. Other problems (e.g.,
current leaks, noise caused by one of the tools, etc.) may not
cause a complete failure of the system, but may complicate or
reduce the utility of other tools connected to the cable.
[0007] Current protections against these types of failures or
malfunctions are limited. Downhole tools may include fuses that are
intended to blow out when a short circuit occurs, thereby
decoupling the tools from the common electrical cable, but they are
not always effective. In some cases, the fuses do not completely
break the connection to the electrical cable. In other cases, the
malfunction may simply not cause a high enough current to destroy
the fuse. In either event, the tool remains coupled to the cable
rather than being electrically isolated.
[0008] It may also be possible to provide an electrical cable for
each of the downhole tools so that the malfunction or failure of
one tool does not affect the others. This, however, is an
impractical solution, as each cable may have to be tens of
thousands of feet long and may cost tens or even hundreds of
thousands of dollars. It would therefore be desirable to provide
some mechanism for preventing the failure or malfunction of one of
the downhole tools from affecting the ability to make use of the
other tools connected to the same cable.
SUMMARY OF THE INVENTION
[0009] This disclosure is directed to systems and methods for
electrically isolating selected ones of a set of downhole tools
that are connected to a common electrical cable that solve one or
more of the problems discussed above. In one particular embodiment,
a system for producing fluids from a well includes surface
equipment, a plurality of downhole tools and a cable coupled
between the surface equipment and the downhole tools. At least one
of the downhole tools is connected to the cable by a coupling
switch. The switch has a closed position in which the downhole tool
is electrically coupled to the cable and an open position in which
the downhole tool is electrically decoupled from the cable. The
downhole tools may include fuses in addition to the coupling
switches. The switch is configured to be remotely actuated to move
between the open and closed positions while the downhole tool is
deployed in the wellbore. The downhole tool may be selectively
coupled to or decoupled from the cable independently of other ones
of the plurality of downhole tools, or an entire string of tools
may be coupled to or decoupled from the cable as a group. The
downhole tools may include sensors, measurement devices, control
devices or other types of tools. The coupling switches may be
actuated by an actuating device that is external to the tools, but
is positioned in close proximity to the tools to actuate the
corresponding coupling switches. The actuating device may be an
electromagnet, a heating element, or some other type of device,
depending upon the requirements of the coupling switches.
[0010] An alternative embodiment comprises a downhole tool. The
downhole tool has one or more electrical components that are
configured to be coupled to a conductor external to the downhole
tool to receive power and/or communicate data. A coupling connects
the downhole tool to the external conductor. A switch is connected
between the electronic components and the electrical coupling. When
the switch is in a closed position, the electronic components are
electrically connected through the coupling to the external
conductor. When the switch is in an open position, the electronic
components are electrically isolated from the external conductor.
The switch is configured to be actuated by an actuating device that
is external to the downhole tool. The downhole tool may include
sensors, measurement devices, control devices or other types of
functional components. The downhole tool may include a fuse
configured to isolate the electronic components from the external
conductor.
[0011] Another alternative embodiment comprises a method. The
method includes deploying downhole tools into the wellbore of a
well, where each of the plurality of downhole tools is connected to
a common cable via a corresponding switch. When it is desired to
connect one of the downhole tools to the common cable or isolate
one of the tools from the common cable, an actuating device is
positioned in close proximity to the targeted downhole tool. The
switch coupled between the downhole tool and the common cable is
then actuated by the actuating device, moving the switch between a
closed position in which the downhole tool is electrically coupled
to the cable and an open position in which the downhole tool is
electrically isolated from the cable. The downhole tool may be
selectively coupled to or decoupled from the cable independently of
other ones of the plurality of downhole tools, or an entire string
of tools may be coupled to or decoupled from the cable as a group.
The method may be performed in response to detecting a malfunction
associated with the downhole tool.
[0012] Numerous other embodiments are also possible.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Other objects and advantages of the invention may become
apparent upon reading the following detailed description and upon
reference to the accompanying drawings.
[0014] FIG. 1 is a diagram illustrating an exemplary well system in
accordance with one embodiment.
[0015] FIG. 2 is a functional block diagram illustrating the
structure of a downhole tool in accordance with one embodiment.
[0016] FIG. 3 is a diagram illustrating the manner in which
coupling switches are actuated by an actuating device in one
embodiment.
[0017] FIG. 4 is a flow diagram illustrating a method for isolating
a downhole tool from a common electrical line in accordance with
one embodiment.
[0018] While the invention is subject to various modifications and
alternative forms, specific embodiments thereof are shown by way of
example in the drawings and the accompanying detailed description.
It should be understood, however, that the drawings and detailed
description are not intended to limit the invention to the
particular embodiment which is described. This disclosure is
instead intended to cover all modifications, equivalents and
alternatives falling within the scope of the present invention as
defined by the appended claims.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0019] One or more embodiments of the invention are described
below. It should be noted that these and any other embodiments
described below are exemplary and are intended to be illustrative
of the invention rather than limiting.
[0020] The present invention includes systems and methods for
electrically isolating selected ones of a set of downhole tools
that are connected to a common electrical cable. The downhole tools
are connected to the cable by switches that can be remotely
actuated to alternately couple the tools to the cable or decouple
the tools from the cable. Selected tools can therefore be
electrically isolated from the cable when the connection is not
required, or when those tools interfere with the operation of other
tools that are connected to the cable.
[0021] One embodiment of the invention is a system for enabling the
electrical isolation of a downhole tool that malfunctions or fails
so that the downhole tool does not affect the operation of other,
interrelated systems. This embodiment is implemented in a system
installed in a well for, e.g., the production of oil, gas or other
fluids. The production system includes power and control equipment
at the surface of the well, downhole tools such as gauges or
control devices installed within the wellbore, and a common
electrical line coupled between the surface equipment and the
downhole tools.
[0022] Each of the downhole tools is connected to the common
electrical line by a corresponding coupling switch. The switch can
be set to either a closed position in which the corresponding
downhole tool is electrically connected to the common electrical
line, or an open position in which the corresponding downhole tool
is electrically disconnected or isolated from the common electrical
line. The coupling switch is actuated by an actuating device that
is separate from and external to the downhole tool. The actuating
device may, for example, use magnetic or electrical fields or
mechanical means to actuate the coupling switches.
[0023] When the downhole tools are initially installed in the
wellbore, the corresponding coupling switches are closed. If it is
desired to isolate one of the downhole tools from the common
electrical line, the actuating device is lowered into the wellbore,
positioned in close proximity to the downhole tool to be isolated,
and activated. The activation of the actuating device causes the
coupling switch to be toggled to the open position, thereby
electrically disconnecting the tool from the common electrical
line. If it is desired to reconnect an isolated downhole tool to
the common electrical line, the same procedure is used to toggle
the corresponding coupling switch to the closed position.
[0024] The present systems and methods provide simple and reliable
means to make or break connections between downhole tools and a
common electrical line. This allows selective isolation of the
tools and provides a number of benefits that are not available in
conventional systems. For example, if a gauge fails and starts
drawing all the available power (current), it could bring down an
entire system. The present systems and methods allow such tools to
be isolated, thereby enabling continued operation of the remainder
of the tools connected to the common line. There could also be
other potential benefits of downhole tool isolation, including
power management, system reconfiguration, and so on.
[0025] Referring to FIG. 1, a diagram illustrating an exemplary
system in accordance with one embodiment of the present invention
is shown. In this embodiment, an oil production system is installed
in a well. Production tubing 110 extends from wellhead 120 into the
wellbore of the well. An electric submersible pump (ESP) 130 is
coupled to the end of production tubing 110. ESP 130 pumps oil
through production tubing 110 to the surface of the well. ESP 130
is electrically coupled to a drive system (not shown) which is
positioned at the surface of the well and provides power to drive
the ESP.
[0026] Several downhole tools (140-142) are also installed in the
well. These tools may include various different types of devices,
including both measurement devices and control devices. For
instance, the downhole tools may comprise gauges or sensors to
monitor temperature, pressure, vibration, flow rate or other
conditions in the well. The downhole tools may also comprise such
control devices as packers which seal selected portions of the
wellbore annulus, and valves which control the flow of fluids in
the well. Each of downhole tools 140-142 is connected to a common
electrical line 150. This line may be, for example, a logging
cable, an electrical wireline, a coiled tubing string equipped with
an electrical conductor, or any other electrical line. At the
surface of the well, a control unit 160 is connected to common
electrical line 150 through a well interface unit 170. Common
electrical line 150 enables the transmission of power and/or data
between the surface equipment (control unit 160 and well interface
unit 170) and downhole tools 140-142.
[0027] Downhole tools 140-142 are intended to be permanently
installed in the well, and are expected to operate for the
productive life of the well, which may be 5-10 years. Even though
the tools are designed to have a high degree of reliability, there
is a possibility that one or more of them may malfunction or fail.
When this occurs, the malfunction or failure may not only prevent
the use of the malfunctioning or failed tool, but may also affect
the remainder of the tools or the surface equipment, all of which
are connected to common electrical line 150. For instance, a
current leak or complete short circuit in one tool may prevent the
other tools from receiving sufficient power. A short circuit or a
malfunction that causes noise on the common line may prevent the
communication of data between the surface equipment and the other
tools.
[0028] The present system therefore uses coupling switches to
connect downhole tools 140-142 to common electrical line 150. The
switches can be actuated to toggle them between closed and open
positions which alternately couple the tools to the common line or
isolate the tools from the common line. The coupling switch for
each downhole tool is selectively actuated (separately and
independently of the switches for the other tools), so that each
tool can be selectively isolated from the common line when
necessary (e.g., when the tool malfunctions and interferes with the
operation of the other tools). This avoids any need to physically
remove the malfunctioning tool (which is extremely costly), and
enables the continued use of the properly functioning tools, which
may allow more efficient operation of the well.
[0029] Referring to FIG. 2, a functional block diagram illustrating
the structure of a downhole tool in accordance with one embodiment
is shown. In this embodiment, downhole tool 200 includes a
functional portion 210 and a coupling portion 220. Functional
portion 210 includes the components necessary to performs the tasks
required of the tool, such as sensing well conditions or
controlling the flow of fluid through the production system. The
components of functional portion 210 include electrical components
211, as well as any necessary mechanical components.
[0030] Electrical component 211 is coupled to the common electrical
line 250 through coupling portion 220. Coupling portion 220
mechanically couples downhole tool 200 to line 250, and also serves
to selectively couple or decouple electrical component 211 to line
250. In one embodiment, coupling portion 220 comprises a cable head
that provides a mechanical connection of the tool's housing to the
portion of the electrical line that gives the line its tensile
strength. Coupling portion 220 incorporates a coupling switch 221
that is connected between electrical component 211 and the
electrical conductor of line 250.
[0031] As noted above, coupling switch 221 has an open position and
a closed position. When coupling switch 221 is closed, electrical
component 211 is electrically coupled to line 250. When coupling
switch 221 is open, electrical component 211 is electrically
isolated from line 250. Coupling switch 221 is configured to be
actuated by an actuating device external to the downhole tool. For
instance, coupling switch 221 could be configured to be actuated by
application of appropriate magnetic fields. The coupling switch
could be an SPDT device that moves in one direction with one
polarity of the activating magnetic flux and to the other direction
with the opposite polarity. In this case, the actuating device
would be a magnet that is positioned in close proximity to the
switch. The physical configuration of coupling portion 220 is
therefore designed to allow the actuating device to be positioned
sufficiently close to coupling switch 221 to actuate and toggle the
switch.
[0032] In one embodiment, electrical component 211 of the downhole
tool includes a fuse. The fuse may be in line with the coupling
switch so that the downhole tool is automatically disconnected from
electrical line 250 in the event of an overcurrent condition. This
fuse does not replace the coupling switch, but provides an
additional level of protection in the event of a short circuit or
similar failure. It should also be noted that, while the fuse may
provide automatic disconnection of the downhole tool from the
common electrical line, it does not enable the tool to be
alternately connected to or isolated from the line (i.e., it does
not allow the tool to be reconnected to the electrical line after
it is disconnected.
[0033] Referring to FIG. 3, a diagram illustrating the manner in
which the coupling switches are actuated by the actuating device in
one embodiment is shown. In this figure, three downhole tools
(341-342) are depicted. Each of downhole tools 340-342 is connected
to a common electrical line 350. Downhole tools 340-342 and line
350 are installed in the annulus of the wellbore between the
production tubing and the wall or casing of the wellbore.
Electrical line 350 extends through wellhead 330 to well interface
unit 360, which is connected to control unit 370.
[0034] Actuation device 310 is connected to a line that allows it
to be lowered into the well through the production tubing. If
actuation device 310 requires no activation (e.g., if it is a
permanent magnet), the line only needs to support the device. If
actuation device 310 requires activation (e.g., if it is an
electromagnet), the line will have a structural component which
provides support for the device, as well as an electrical component
that allows the device to be activated or otherwise controlled.
[0035] When it is desired to either isolate one of the downhole
tools from line 350 or couple the tool to line 350, actuation
device 310 is lowered through the production tubing into a position
in which it is in close proximity to the targeted tool. If
actuation device 310 is a type that requires no activation, the
proximity of the device to the targeted tool will actuate the
coupling switch and cause it to toggle from the current position to
the other position (i.e., from the closed position to the open
position, or from the open position to the closed position). If
actuation device 310 requires activation, it is activated after
being positioned in proximity to the targeted tool, thereby causing
the tool's coupling switch to toggle and either couple the tool to
the common electrical line or electrically isolate the tool from
the common line.
[0036] For the purposes of this disclosure, "close proximity" to
the targeted tool should be construed to mean that the actuation
device is close enough to the targeted downhole tool to cause the
tool's coupling switch to be actuated and toggled from one position
to the other. In the embodiment described above, the coupling
switch is preferably positioned adjacent to the production tubing
in order to facilitate its actuation by the actuating device. In
other embodiments, the actuating device may be positioned external
to the production tubing, so it may be preferable to position the
coupling switch away from the production tubing.
[0037] It may be beneficial to employ an actuation device of a type
that requires activation in order to provide improved control of
the actuation process. Exemplary devices may include electromagnets
or devices that selectively generate electric fields. While
inactivated, the device can be moved past non-targeted downhole
tools without inadvertently actuating the coupling switches of
these tools. Then, when the actuation device is properly
positioned, it can be activated to cause actuation of the targeted
tool. If an actuation device that does not require activation is
used, it may be desirable to implement the actuation of the
switches in a manner that requires the actuation device to be in
proximity to a switch for some predetermined minimum amount of time
in order to actuate the switch. This would prevent the switches of
non-targeted tools from being actuated when the actuating device
passes these tools in the wellbore. Alternatively, the actuating
device could be required to be properly aligned with a targeted
tool before the tool's switch could be actuated.
[0038] Referring to FIG. 4, a flow diagram illustrating a method in
accordance with one embodiment is shown. The method includes
positioning multiple downhole tools in a wellbore, where each of
the tools is connected to a common electrical line (410). It is
then determined that one of the downhole tools should be
disconnected (420). This determination may be based on various
considerations, such as a short circuit or other malfunction in one
of the tools that affects the other tools, a malfunction that
prevents the tool from operating as intended (but does not affect
the other tools), completion of the tool's function (e.g., an
electrically set packer that has already been set), and so on. Once
it has been determined that one of the downhole tools (the targeted
tool) should be isolated from the common line, an actuating device
is lowered into the wellbore and positioned in close proximity to
the targeted tool (430). The coupling switch of the targeted tool
is then actuated by the actuating device (440) to toggle the switch
from the closed (connected) position to the open (isolated)
position. A similar procedure can be used to identify and reconnect
selected downhole tools to the common electrical line.
[0039] The embodiments described above are exemplary, and many
variations of the features described above may be implemented in
alternative embodiments. For example, while the foregoing
embodiments utilize magnetically actuated coupling switches, an
alternative embodiment could use a heat-actuated switch that
employs a shape memory alloy to change from one switch position to
another. The actuating device in such an embodiment would be a
heating element.
[0040] In the embodiments described above, multiple downhole tools
are coupled to a single, common electrical line. In alternative
embodiments, there may be a single downhole tool coupled to the
line, or there may be multiple electrical lines, each of which has
one or more downhole tools coupled to it. In yet another
embodiment, a string of multiple downhole tools may be coupled to
the electrical line by a single coupling switch.
[0041] The benefits and advantages which may be provided by the
present invention have been described above with regard to specific
embodiments. These benefits and advantages, and any elements or
limitations that may cause them to occur or to become more
pronounced are not to be construed as critical, required, or
essential features of any or all of the claims. As used herein, the
terms "comprises," "comprising," or any other variations thereof,
are intended to be interpreted as non-exclusively including the
elements or limitations which follow those terms. Accordingly, a
system, method, or other embodiment that comprises a set of
elements is not limited to only those elements, and may include
other elements not expressly listed or inherent to the claimed
embodiment.
[0042] While the present invention has been described with
reference to particular embodiments, it should be understood that
the embodiments are illustrative and that the scope of the
invention is not limited to these embodiments. Many variations,
modifications, additions and improvements to the embodiments
described above are possible. It is contemplated that these
variations, modifications, additions and improvements fall within
the scope of the invention as detailed within the following
claims.
* * * * *