Note: Descriptions are shown in the official language in which they were submitted.
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WELLBORE TELEMETRY SYSTEM AND METHOD
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims priority to U.S. Provisional Application Serial Number
60/697,073, filed on July 5, 2005 and entitled "WELLBORE TELEMETRY SYSTEM AND
METHOD."
FIELD OF THE DISCLOSURE
[0001] The present disclosure relates to telemetry systems and methods for use
in wellbore
operations. More particularly, the present disclosure relates to wellbore
telemetry systems
and methods for conveying signals between a surface unit and a downhole tool.
BACKGROUND
[0002] Wellbores may be drilled to locate and produce hydrocarbons. Typically,
a wellbore
is formed by advancing a downhole drilling tool having a drill bit at one end
into the ground.
As the drilling tool is advanced, drilling fluid ("mud") is pumped from a
surface mud pit
through a passage or passages in the drilling tool and out the drill bit. The
mud exiting the
drill bit flows back to the surface to be returned to the mud pit and may be
re-circulated
through the drilling tool. In this manner, the drilling mud cools the drilling
tool, carries
cuttings and other debris away from the drilling tool, and deposits the
cuttings and other
debris in the mud pit. As is known, in addition to the cooling and cleaning
operations
performed by the mud pumped into the wellbore, the mud forms a mudcake that
lines the
wellbore which, among other functions, reduces friction between the drill
string and
subterranean formations.
[0003] During drilling operations (i.e., advancement of the downhole drilling
tool),
communications between the downhole drilling tool and a surface-based
processing unit
and/or other surface devices may be performed using a telemetry system. In
general, such
telemetry systems enable the conveyance of power, data, commands, and/or any
other signals
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or information between the downhole drilling tools / bottom hole assemble
(BHA) and the
surface devices. Thus, the telemetry systems enable, for example, data related
to the
conditions of the wellbore and/or the downhole drilling tool to be conveyed to
the surface
devices for further processing, display, etc. and also enable the operations
of the downhole
drilling tool to be controlled via commands andlor other information sent from
the surface
devices) to the downhole drilling tool.
[0004] One known wellbore telemetry system 100 is depicted in FIG. 1. A more
detailed
description of such a known system is found in U.S. Patent No. 5,517,464,
which is
incorporated by reference herein in its entirety. With reference to FIG. 1, a
drilling rig 10
includes a drive mechanism 12 to provide a driving torque to a drill string
14. The lower end
of the drill string 14 extends into a wellbore 30 and carries a drill bit 16
to drill an
underground formation 18. During drilling operations, drilling mud 20 is drawn
from a mud
pit 22 on a surface 29 via one or more pumps 24 (e.g., reciprocating pumps).
The drilling
mud 20 is circulated through a mud line 26 down through the drill string 14,
through the drill
bit 16, and back to the surface 29 via an annulus 28 between the drill string
14 and the wall of
the wellbore 30. Upon reaching the surface 29, the drilling mud 20 is
discharged through a
line 32 into the mud pit 22 so that rock and/or other well debris carried in
the mud can settle
to the bottom of the mud pit 22 before the drilling mud 20 is recirculated.
[0005] As shown in FIG. 1, a downhole measurement while drilling (MWD) tool 34
is
incorporated in the drill string 14 near the drill bit 16 for the acquisition
and transmission of
downhole data or information. The MWD tool 34 includes an electronic sensor
package 36
and a mudflow wellbore telemetry device 38. The mudflow telemetry device 38
can
selectively block the passage of the mud 20 through the drill string 14 to
cause pressure
changes in the mud line 26. In other words, the wellbore telemetry device 38
can be used to
modulate the pressure in the mud 20 to transmit data from the sensor package
36 to the
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surface 29. Modulated changes in pressure are detected by a pressure
transducer 40 and a
pump piston sensor 42, both of which are coupled to a processor (not shown).
The processor
interprets the modulated changes in pressure to reconstruct the data collected
and sent by the
sensor package 36. The modulation and demodulation of a pressure wave are
described in
detail in commonly assigned U.S. Patent No. 5,375,098, which is incorporated
by reference
herein in its entirety.
[0006] In addition to the known mud pulse telemetry system 100 depicted in
FIG. 1, other
wellbore telemetry systems may be used to establish communication between a
downhole
tool and a surface unit. Examples of known telemetry systems include a wired
drill pipe
wellbore telemetry system as described in U.S. Patent No. 6,641,434, an
electromagnetic
wellbore telemetry system as described in U.S. Patent No. 5,624,051, an
acoustic wellbore
telemetry system as described in published PCT Patent Application No.
W02004085796, all
of which are hereby incorporated by reference herein in their entireties.
Further examples
using data conveyance or communication devices (e.g., transceivers coupled to
sensors) have
also been used to convey power and/or data between a downhole tool and a
surface unit.
[0007] Despite the development and advancement of wellbore telemetry devices
in wellbore
operations, there remains a need for additional reliability and wellbore
telemetry capabilities
for wellbore operations. As with other many other wellbore devices, wellbore
telemetry
devices sometimes fail. Additionally, the power provided by many known
wellbore
telemetry devices may be insufficient to power desired wellbore operations.
Attempts have
been made to use two different types of mud pulse telemetry devices in a
downhole tool. In
particular, each of the different mud pulse telemetry devices is typically
positioned in the
downhole tool and communicatively linked to a different, respective surface
unit. Such
wellbore telemetry tools have been run simultaneously and non-simultaneously
and at
different frequencies. Attempts have also been made to develop dual channel
downhole
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wellbore telemetry for transmitting data streams via communication channels to
be
interpreted independently as described in U.S. Patent No. 6,909,667.
[0008] Despite the above-noted advancements in wellbore telemetry systems,
there remains a
need to provide wellbore telemetry systems capable of providing added
reliability, increased
speed, and increased power capabilities. As set forth in the detailed
description below, the
example methods and apparatus enable telemetry systems to operate at one or
more desired
frequencies and provide increased bandwidth. Additionally, the example methods
and
apparatus described below enable a plurality of different wellbore telemetry
devices to be
combined with a variety of one or more downhole components, such as formation
evaluation
tools, to provide flexibility in performing wellbore operations. Still
further, the example
methods and apparatus described below provide backup wellbore telemetry
capability, enable
the operation of multiple identical or substantially similar wellbore
telemetry tools, enable the
generation of comparative wellbore measurements, enable the activation of
multiple wellbore
telemetry tools, increase the available bandwidth and/or data transmission
rates for
communications between one or more downhole tools and one or more surface
units, and
enable adaptation of the wellbore telemetry tools to different and/or varying
wellbore
conditions.
SUMMARY
[0009] In accordance with one disclosed example, a wellbore communication
system for a
wellsite having a downhole tool deployed in a wellbore penetrating a
subterranean formation
includes a first mud pulse telemetry device disposed in the downhole tool. The
example
system may also include at least one additional telemetry device other than a
mud pulse
telemetry device and disposed in the wellbore. Additionally, the example
system may
include at least one of a pressure transducer or a pressure sensor adapted to
detect a
modulated pressure provided by at least one of the telemetry devices.
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[0010] In another disclosed example, a wellbore communication system for a
wellsite having
a downhole tool deployed in a wellbore penetrating a subterranean formation
includes a
plurality of wellbore telemetry systems. At least one of the wellbore
telemetry systems may
comprise a wired drill pipe telemetry system. The example system may also
include at least
one surface unit in communication with at least one of the plurality of
wellbore telemetry
systems.
[0011] In yet another disclosed example, a wellbore communication system for a
wellsite
having a downhole tool deployed in a wellbore penetrating a subterranean
formation includes
at least one formation evaluation component to measure at least one wellbore
parameter. The
example system may also include a plurality of wellbore telemetry systems. At
least one of
the wellbore telemetry systems may be in communication with the at least one
formation
evaluation component to receive data therefrom and to transmit the data to a
surface unit.
[0012] In still another disclosed example, a method of communicating between a
surface
location and a downhole tool deployed in a wellbore penetrating a subterranean
formation
evaluates a subterranean formation using at least one downhole component
positioned in the
downhole tool. The downhole tool may comprise a plurality of wellbore
telemetry systems.
The example method may also selectively transmit data from the at least one
downhole
component to a surface unit via at least one of the wellbore telemetry
systems.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a schematic view, partially in cross-section, of a known
measurement while
drilling tool and wellbore telemetry device connected to a drill string and
deployed from a rig
into a wellbore.
[0014] FIG. 2 is a schematic view, partially in cross-section, of an example
telemetry system
including a downhole tool having multiple mud pulse telemetry devices.
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[0015] FIG. 3 is a schematic view, partially in cross-section, of another
example telemetry
system including a downhole tool having a wired drill pipe wellbore telemetry
device.
[0016] FIG. 4 is a schematic view, partially in cross-section, of a yet
another example
telemetry system including a downhole tool having a mud pulse telemetry device
and an
electromagnetic wellbore telemetry device.
[0017] FIG. 5 is a schematic view, partially in cross-section, of still
another example
telemetry system including a downhole tool having multiple downhole components
and
multiple wellbore telemetry devices.
DETAILED DESCRIPTION
[0018] Certain examples are shown in the above-identified figures and
described in detail
below. In describing these examples, like or identical reference numbers are
used to identify
common or similar elements. The figures are not necessarily to scale and
certain features and
certain views of the figures may be shown exaggerated in scale or in schematic
for clarity
and/or conciseness.
[0019] Referring now to FIG. 2, a mud pulse wellbore telemetry system 200
having multiple
telemetry devices is shown. In contrast to the known system 100 of FIG. 1, the
example
wellbore telemetry system 200 includes two MWD tools 234a and 234b, two mud
pulse
telemetry devices 238a and 238b, two transducers 240a and 240b, and two
sensors 242a and
242b. Additionally, the MWD tools 234a and 234b may communicate with a single
surface
computer or unit 202 via the mud pulse telemetry devices 238a and 238b. As can
be seen in
the example system 200 of FIG. 2, the mud pulse telemetry devices 238a and
238b are
identical or substantially identical, the MWD tools 234a and 234b are
identical or
substantially identical, and the devices 238a and 238b and the tools 234a and
234b are
positioned within a single downhole tool 201 (i.e., the same downhole tool).
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[0020] The surface unit or computer 202 may be implemented using any desired
combination
of hardware and/or software. For example, a personal computer platform,
workstation
platform, etc. may store on a computer readable medium (e.g., a magnetic or
optical hard
disk, random access memory, etc.) and execute one or more software routines,
programs,
machine readable code or instructions, etc. to perform the operations
described herein.
Additionally or alternatively, the surface unit or computer 202 may use
dedicated hardware or
logic such as, for example, application specific integrated circuits,
configured programmable
logic controllers, discrete logic, analog circuitry, passive electrical
components, etc. to
perform the functions or operations described herein.
[0021] Still further, while the surface unit 202 is depicted in the example of
FIG. 2 as being
relatively proximate to the drilling rig 10, some part of or the entire
surface unit 202 may
alternatively be located relatively remotely from the rig 10. For example, the
surface unit
202 may be operationally and/or communicatively coupled to the wellbore
telemetry system
200 via any combination of one or more wireless or hardwired communication
links (not
shown). Such communication links may include communications via a packet
switched
network (e.g., the Internet), hardwired telephone lines, cellular
communication links and/or
other radio frequency based communication links, etc. using any desired
communication
protocol.
[0022] Returning in detail to FIG. 2, the MWD tools 234a and 234b may be
implemented
using the same devices) used to implement the MWD tool 34 of FIG. 1.
Similarly, the mud
pulse telemetry devices 238a and 238b may be implemented using the same
devices) used to
implement the mud pulse telemetry device 38 of FIG. 1. An example of a mud
pulse
telemetry device that may be used or otherwise adapted to implement the
devices 38, 238a,
and 238b is described in U.S. Patent No. 5,517,464, which has previously been
incorporated
by reference.
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[0023] In operation, the example wellbore telemetry system 200 of FIG. 2 uses
the mud pulse
telemetry devices 238a and 238b to generate signals (e.g., modulated pressure
signals) in the
mud 20 flowing in the annulus 28 of the wellbore 30. These generated signals
(e.g.,
modulated or varying pressure signals) may be sensed by one or more of the
pressure
transducers 240a and 240b and/or the pressure sensors 242a and 242b and
analyzed by the
surface unit 202 to extract or otherwise obtain data or other information
relating to the
operational conditions) of the downhole tool 201 (e.g., one or both of the MWD
tools 234a
and 234b), conditions in wellbore 30, and/or any other desired downhole
information. In this
manner, communications may be established between the downhole tool 201 and,
thus,
between the MWD tools 234a and 234b, and the surface unit 202. More generally,
such
communications between the downhole tool 201 and the surface unit 202 may be
established
using uplink and/or downlink systems. Further, while mud pulse telemetry
devices 238a and
238b are described in connection with the example telemetry system 200 of FIG.
2, other
types of wellbore telemetry devices may be employed instead of or in addition
to the mud
pulse telemetry devices 238a and 238b. For example, one or more mud sirens,
positive pulse
mud flow telemetry devices, and/or negative pulse mud flow telemetry devices
may be used.
[0024] In general, the example wellbore telemetry systems described herein may
use
telemetry devices arranged or positioned in various configurations relative to
the downhole
tool. In the example of FIG. 2, one or both of the telemetry devices 238a and
238b may be
operatively or communicatively coupled to the same (i.e., a single) MWD tool
(e.g., the tool
234a or the tool 234b). Alternatively, each of the telemetry devices 238a and
238b may be
operatively or communicatively coupled to different respective tools. For
example, the
telemetry device 238a may be communicatively or operatively coupled to the MWD
tool
234a and the telemetry device 238b may be communicatively or operatively
coupled to the
MWD tool 234b, as depicted in FIG. 2. As described in greater detail below,
one or both of
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the telemetry devices 238a and 238b may be communicatively or operatively
coupled to one
or more additional downhole components.
[0025] Turning again to the operation of the example system 200 of FIG. 2, the
mud pulse
telemetry devices 238a and 238b may send uplink signals (e.g., varying or
modulated
pressure signals to be conveyed up along the annulus 28 to the surface 29) by
altering the
flow of mud through the telemetry devices 238a and 238b. Such uplink signals
(e.g., varying
or modulated pressure signals) are sensed or detected by the pressure
transducers 240a and
240b and/or the pressure sensors 242a and 242b. In particular, the uplink
signals generated
by the telemetry device 238a may be detected or sensed by the transducer 240a
and/or the
pressure sensor 242a. Similarly, the uplink signals generated by the telemetry
device 238b
may be detected or sensed by the transducer 240b and/or the pressure sensor
242b. The
pressure transducers 240a and 240b may be implemented using devices identical
or similar to
that used to implement the pressure transducer 40 of FIG. l, and the sensors
242a and 242b
may be implemented using devices identical or similar to that used to
implement the sensor
42 of FIG. 1.
[0026] FIG. 3 is a schematic view, partially in cross-section, of another
example telemetry
system 300 including a downhole tool 301 having a wired drill pipe wellbore
telemetry
system or device 348. In contrast to the known mud pulse telemetry system 100
depicted in
FIG. 1, the example telemetry system 300 utilizes a mud pulse telemetry device
338 that is
housed in a MWD tool 334 and includes the wired drill pipe telemetry system
348.
[0027] As shown in FIG. 3, the MWD tool 334 and the mud pulse telemetry device
338 may
be positioned in the downhole tool 301. The MWD tool 334 may be implemented
using a
device that is similar or identical to that used to implement the MWD tool 34
of the FIG. 1
and/or the MWD tools 234a and 234b of FIG. 2. Similarly, the mud pulse
telemetry device
338 may be implemented using a device that is similar or identical to that
used to implement
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the mud pulse telemetry device 38 of FIG. 1 and/or the mud pulse telemetry
devices 238a and
238b of FIG. 2. Additionally, the surface unit or computer 302 may be
implemented in a
manner similar to the surface unit or computer 202 described in connection
with FIG. 2.
Thus, the surface unit 302 may be operatively or communicatively coupled to
the MWD tool
334 via the mud pulse telemetry device 338 and/or may be operatively or
communicatively
coupled to the wired drill pipe telemetry system 348 via one or more
communication links
(not shown). As with the example system 200 of FIG. 2, the surface unit or
computer 302
may be proximate the drilling rig 10 or, alternatively, some or all of the
surface unit or
computer 302 may be remotely located relative to the drilling rig 10.
[0028] Turning in detail to the wired drill pipe wellbore telemetry system
348, it can be seen
in the example of FIG. 3 that the system 348 extends substantially entirely
through the drill
string 14. An example of a wired drill pipe wellbore telemetry system that may
be used to
implement the system 348 is described in U.S. Patent No. 6,641,434, which has
been
previously incorporated by reference herein. As depicted in FIG. 3, the wired
drill pipe
wellbore telemetry system 348 includes a plurality or series of wires 352
positioned in each
drill pipe 350 that forms or composes the drill string 14. A coupler 354 is
positioned at the
end of each of the drill pipes 350 so that when the pipes 350 are connected,
joined, or
otherwise coupled, the drill string 14 provides a hardwired communication link
extending
through the drill string 14. While the wired drill pipe telemetry system 348
is depicted in
FIG. 3 as extending substantially entirely through the drill string 14 to the
MWD tool 334, the
wired drill pipe telemetry system 348 may instead extend only partially
through the drill
string 14.
[0029] During operation, either or both of the mud pulse telemetry device 338
and the wired
drill pipe system 348 may be used to enable communications between the
downhole tool 301
(e.g., the MWD tool 334) and the surface unit 302. Depending on the particular
operational
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mode of the rig 10 and/or downhole or other environmental conditions, the
device 338 or the
system 348 may be best suited to convey data to the surface unit 302.
Alternatively or
additionally, both the device 338 and the system 348 may be used to convey
information
between the surface unit 302 and the downhole tool 301 at the same time. In
such a case, the
conveyed information may concern the same downhole parameters) or conditions)
or
different parameters) or condition(s).
[0030] FIG. 4 is a schematic view, partially in cross-section, of a yet
another example
telemetry system 400 including a downhole tool 401 having a mud pulse
telemetry device
438 and an electromagnetic wellbore telemetry device 448. Similar to the
systems 200 and
300 depicted in FIGS. 2 and 3, respectively, the system 400 includes a surface
unit or
computer 402 that can communicate with the downhole tool 401 and/or other
downhole
components and analyze information obtained therefrom. In this manner, the
surface unit
402 may be operationally or otherwise coupled to a MWD tool 434 via, for
example, the mud
pulse telemetry device 438. Still further, as with the other systems 200 and
300, the surface
unit 402 may be proximate the drilling rig 10 as shown, or some or all of the
surface unit 402
may be remotely located relative to the drilling rig 10 and communicatively
coupled via, for
example, any desired combination of wireless and hardwired communication links
to the
system 400.
[0031] The mud pulse telemetry device 438 is position in the downhole tool 401
and may be
implemented using the same device or a device similar to the device used to
implement the
device 38 of FIG. 1, the devices 238a and 238b of FIG. 2, and/or the device
338 of FIG. 3.
Also, the MWD tool 434 is positioned in the downhole tool 401 and may be
implemented
using the same device or a device similar to the device used to implement the
devices) used
to implement the tools 234a and 234b of FIG. 2, and/or 334 of FIG. 3.
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[0032) The electromagnetic wellbore telemetry system 448 includes a downhole
transceiver
454 and a surface transceiver 452. An example of an electromagnetic wellbore
telemetry
system that may be used to implement the system 448 of FIG. 4 is described in
U.S. Patent
No. 5,624,051, previously incorporated by reference herein. As depicted in the
example of
FIG. 4, the electromagnetic wellbore telemetry system 448 is also provided
with a gap collar
450, which is position in the downhole tool 401 to enhance the electromagnetic
signals
conveyed between the transceivers 452 and 454. An example of a gap collar that
may be
used to implement the collar 450 is described in U.S. Patent No. 5,396,232.
[0033] While the example systems depicted in FIGS. 2-4 include certain
combinations of
mud pulse telemetry, wired drill pipe telemetry, and electromagnetic telemetry
systems, other
combinations of such systems may be employed to achieve the same or similar
results. For
example, a wellbore telemetry system using a mud siren, positive and/or
negative pulse
telemetry devices, an acoustic telemetry device, a tortional wave telemetry
device, or any
other telemetry devices) could be used instead of or in addition to those
depicted in FIGS. 2-
4 to communicate with a surface unit or computer. Additionally, various
combinations of
communication links (e.g., wireless, hardwired, etc.) may be employed to
provide selective
communications between the surface unit and the telemetry devices to suit the
needs of
particular applications.
[0034] Still further it should be understood that the telemetry devices, or
any combination
thereof, used with the example systems described herein may be positioned in
various
configurations about the downhole tool. For example, the devices may be
positioned
adjacent to each other or, alternatively, at some desired distance or spacing
apart, with or
without components disposed therebetween. The telemetry devices may be
oriented
vertically as shown in the examples, or one or more of the devices may be
inverted.
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[0035] FIG. 5 is a schematic view, partially in cross-section, of still
another example
telemetry system 500 including a downhole tool 501 having multiple downhole
components
and multiple wellbore telemetry devices. As depicted in the example system 500
of FIG. 5,
the downhole tool 501 includes two MWD tools 534a and 534b, two mud pulse
telemetry
devices 538a and 538b, two pressure transducers 540a and 540b, and two sensors
542a and
542b.
[0036] A surface unit or computer 502, which may be similar or identical to
one or more of
the example surface units 202, 302, and 402 of FIGS. 2, 3, and 4,
respectively, may be
communicatively and/or operationally coupled to the telemetry devices 538a and
538b and/or
downhole components 548a and 548b. As with the other example surface units
202, 302, and
404, the example surface unit 502 may be proximate (e.g., onsite) or remotely
situated (e.g.,
offsite) relative to the rig 10 and operationally and/or otherwise coupled to
the telemetry
systems, MWD tools 534a and 534b, and/or mud pulse telemetry devices 538a and
538b via
any desired communication links (not shown). The MWD tools 534a and 534b may
be
implemented using devices similar or identical to those used to implement the
MWD tools
34, 234a, 234b, 334, and/or 434. Similarly, the mud pulse telemetry devices
538a and 538b
may be implemented using devices similar or identical to those used to
implement the mud
pulse telemetry devices 38, 238a, 238b, 338, andJor 438.
[0037] As depicted in FIG. 5, the downhole tool 501 houses the MWD tools 534a
and 534b,
the mud pulse telemetry devices 538a and 538b, and the downhole components
548a and
548b. In the example of FIG. 5, the downhole components 548a and 548b are
depicted as
formation evaluation tools, which may be used to test and/or sample fluid from
a surrounding
formation. Examples of such formation evaluation tools that may be used to
implement the
tools 548a and 548b are described in published U.S. Patent Application No.
2005/01109538,
which is incorporated by reference herein in its entirety. As shown, the
downhole
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components 548a and 548b include stabilizer blades 552a and 552b with probes
554a and
554b for drawing fluid into the downhole tool 501, and backup pistons 550a and
550b to
assist in driving the probes 554a and 554b into position against the wall of
the wellbore 30.
The formation evaluation components 548a and 548b may enable various pressure
testing
and/or sampling procedures to be performed. Although the example of FIG. 5
depicts two
formation evaluation components in the downhole tool 501, one or more than two
formation
evaluation components may be used instead.
[0038] In the example of FIG. 5, the wellbore telemetry devices 538a and 538b
are
operationally coupled to the respective downhole components 548a and 548b.
However, one
or more wellbore telemetry devices may be coupled to one or more formation
evaluation
components. For example, two wellbore telemetry devices may be coupled to the
same
downhole component or, alternatively, each wellbore telemetry device may be
coupled to a
single, respective downhole component. Additionally, a variety of formation
evaluation
components may be coupled to one or both of the wellbore telemetry devices
538a and 538b.
As used herein, "formation evaluation component" refers to a device for
performing
formation evaluation such as, for example, sampling, detecting formation
pressure while
drilling, measuring resistivity, nuclear magnetic measurements, or any other
downhole tool
used to evaluate a subterranean formation.
[0039] Multiple wellbore telemetry devices and/or systems such as those
described in
connection with the example systems herein may be used to provide downhole
tools with the
ability to perform independent or integrated downhole operations. For example,
one wellbore
telemetry system and/or telemetry device may be used in conjunction with a
downhole
formation evaluation component to perform various testing operations, while a
second
telemetry device may be used to perform resistivity operations. Additional
wellbore
telemetry systems and/or devices may be provided as desired. In some cases it
may be
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desirable to use certain wellbore telemetry systems or devices in conjunction
with certain
downhole components to perform certain downhole operations.
[0040] Measurements taking using the wellbore telemetry devices may be
compared and
analyzed. In this manner, duplicate or redundant measurements may be taken for
calibration
and/or verification purposes. Additionally, duplicate or redundant
measurements may be
taken at different positions (at the same or different times) to determine
differences in the
formation at various downhole locations. Measurements taken by different
components may
also be analyzed to determin6 e, for example, performance capabilities and/or
formation
properties.
[0041] The separate or individual functionality of the wellbore telemetry
devices may also be
used to supply and/or enhance power capabilities for instruments or tools
downhole / in the
BHA as needed to perform continuous or additional operations. For example,
embodiments
of the systems disclosed herein may be implemented with a power source (e.g.
batteries) or
power generator (e.g. mud turbine), as known in the art, to provide the
desired energy. Yet
other embodiments may be implemented for power transmission via
electromagnetic energy
conveyance using the wired drill pipe systems disclosed herein.
[0042] Multiple wellbore telemetry devices may also be used to increase data
transmission
rates to the surface and/or to eliminate the need for batteries in the
downhole tool. The use of
multiple wellbore telemetry devices may also provide a backup system in a case
where one of
the wellbore telemetry systems fails or is otherwise unable to function
properly. Further, in
cases where two different wellbore telemetry systems and/or devices are used,
alternative
types of communications may be employed as desired or needed to provide more
effective
communications between a downhole tool and a surface unit. Still further, any
desired
communication medium (e.g., gas/gas mixtures including air, methane, nitrogen,
mud, etc.)
CA 02551090 2006-06-27
or combination of media may be used to implement the telemetry systems
described herein.
For example, any combination of wireless and/or hardwired media may be used to
suit the
needs of particular applications. More specifically, wireless media may
include drilling mud,
electromagnetic signals, acoustic signals, etc., and hardwired media may
include wired drill
pipe and/or any other media using electrical conductors. In some cases,
especially when
running under-balanced drilling, inert gas like nitrogen, methane or air is
mixed to reduce the
weight of the mud. If there is an excessive amount of gas is in the mud
system, mud pulse
telemetry systems often fail to work. In some cases only pressurized gas is
used for drilling.
In these cases electromagnetic and/or wired drill pipe telemetry systems of
the invention may
be used. A combination of these telemetry systems or multiple electromagnetic
or other
telemetry devices can also be used as disclosed herein.
[0043] As noted above in connection with the examples of FIGS. 2, 3, 4, and 5,
the surface
units 202, 302, 402, and/or 502 may be located onsite or offsite (e.g.,
relative to the rig) and
may be communicatively and/or operationally coupled to one or more respective
downhole
tools via communication links (not shown). The communication links may be
implemented
using any desired wireless and/or hardwired link capable of transmitting data
between
wellbore telemetry devices and surface units or computers. In some examples,
the
communication link may be coupled to a wellbore telemetry device via an
intermediary
device such as, for example, a pressure transducer. The communication link
provides means
for passing signals such as command, data, power or other signals between the
wellbore
telemetry devices and the surface computer. These signals may be used to
control the
downhole tool and/or to retrieve data collected by the downhole tool.
Preferably, but not
necessarily, signals are passed in real time to provide fast and efficient
data collection, tool
operation and/or response to wellbore conditions.
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CA 02551090 2006-06-27
[0044] One or more communication links may be provided to operatively couple
the wellbore
telemetry systems) and/or devices) to one or more surface unit(s). In this
manner, each
wellbore telemetry device and/or system can selectively communicate with one
or more
surface unit(s). Alternatively, such links may couple the wellbore telemetry
systems) and/or
device(s). The telemetry devices) may communicate with the surface via a
wellbore
telemetry system. Various communication links may be provided so that the
wellbore
telemetry devices and/or systems may communicate with each other and/or the
surface units)
independently, simultaneously or substantially simultaneously, alternately
(e.g., while one
telemetry device is actively communicating, other telemetry devices are not
actively
communicating), and/or during selected (e.g., predetermined) time frames or
intervals.
[0045] The signals and/or other communications conveyed via the example
wellbore
telemetry systems described herein may be used or manipulated to enable the
efficient flow
of data or information. For example, the example telemetry devices and/or
systems may be
selectively operated to pass data from the downhole tool to the surface unit
or computer.
Such data may be passed from the telemetry devices and/or systems at similar
or different
frequencies, simultaneously or substantially simultaneously, and/or
independently. The data
and/or signals may be selectively manipulated, analyzed, or otherwise
processed to generate
an optimum and/or desired data output. The data (e.g., the output data) may be
compared
(e.g., to reference values, threshold values, etc.) and/or analyzed to
determine wellsite
conditions, which may be used to adjust operating conditions, locate valuable
hydrocarbons,
and/or perform any other desired wellsite operations or functions.
[0046] It will be understood from the foregoing description that the example
systems and
methods described herein may be modified from the specific embodiments
provided. For
example, the communication links described herein may be wired or wireless.
The example
devices described herein may be manually and/or automatically activated or
operated to
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CA 02551090 2006-06-27
perform the desired operations. Such activation may be performed as desired
and/or based on
data generated, conditions detected, and/or results from downhole operations.
[0047] The foregoing description and example systems and methods provided
thereby are for
purposes of illustration only and are not to be construed as limiting. Thus,
although certain
apparatus and methods have been described herein, the scope of coverage of
this patent is not
limited thereto. To the contrary, this patent covers all embodiments fairly
falling within the
scope of the appended claims either literally or under the doctrine of
equivalents.
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