U.S. patent application number 14/031816 was filed with the patent office on 2015-03-19 for telemetry on tubing.
The applicant listed for this patent is Halliburton Energy Services, Inc.. Invention is credited to Li Gao, Vimal V. Shah.
Application Number | 20150077265 14/031816 |
Document ID | / |
Family ID | 52667465 |
Filed Date | 2015-03-19 |
United States Patent
Application |
20150077265 |
Kind Code |
A1 |
Gao; Li ; et al. |
March 19, 2015 |
TELEMETRY ON TUBING
Abstract
In some embodiments, an apparatus and a system, as well as a
method and an article, may operate to program a first acoustic
repeater to transmit information at a first operating frequency; to
couple the first acoustic repeater circumferentially around a
coiled tubing portion, an inner diameter of the first acoustic
repeater being about equal to an outer diameter of the coiled
tubing portion; to program a second acoustic repeater to receive
information transmitted by the first acoustic repeater; and to
receive sensor information transmitted at the first operating
frequency by the first acoustic repeater and relayed by the second
acoustic repeater, the second acoustic repeater being coupled to
the coiled tubing portion uphole from the first acoustic repeater.
Additional apparatus, systems, and methods are disclosed.
Inventors: |
Gao; Li; (Katy, TX) ;
Shah; Vimal V.; (Sugarland, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Halliburton Energy Services, Inc. |
Houston |
TX |
US |
|
|
Family ID: |
52667465 |
Appl. No.: |
14/031816 |
Filed: |
September 19, 2013 |
Current U.S.
Class: |
340/853.7 |
Current CPC
Class: |
E21B 17/10 20130101;
E21B 47/16 20130101 |
Class at
Publication: |
340/853.7 |
International
Class: |
E21B 47/14 20060101
E21B047/14 |
Claims
1. A coiled tubing acoustic telemetry system, comprising: a length
of coiled tubing; and a first repeater apparatus including, an
acoustic transmitter, electrical circuitry configured to drive the
acoustic transmitter to generate acoustic signals, and an annular
housing configured to enclose the acoustic transmitter and to
engage an outer surface of the coiled tubing, the annular housing
having an inner diameter about equal to an outer diameter of the
length of coiled tubing; and a second repeater apparatus coupled to
the coiled tubing portion and spaced at a distance downhole from
the first repeater apparatus, the second repeater apparatus
including an acoustic transmitter and an annular housing configured
to enclose the acoustic transmitter and to engage an outer surface
of the coiled tubing, the annular housing having an inner diameter
about equal to an outer diameter of the coiled tubing portion.
2. The system of claim 1 wherein the annular housing has an outer
diameter larger than an inner diameter of a stripper packer
assembly.
3. The system of claim 1, wherein the acoustic transmitter includes
a flexible piezoelectric actuator.
4. The system of claim 1, wherein the electrical circuitry is
housed in another annular housing separate from the annular
housing.
5. The system of claim 1, wherein the first repeater apparatus
further includes a flexible battery element including a plurality
of battery portions.
6. The system of claim 5, wherein a battery portion of the
plurality of battery portions being enclosed in another annular
housing separate from the annular housing.
7. A method for providing communication between acoustic repeaters
and a surface system, the method comprising: programming a first
acoustic repeater to transmit information at a first operating
frequency; coupling the first acoustic repeater circumferentially
around a coiled tubing portion, an inner diameter of the first
acoustic repeater being about equal to an outer diameter of the
coiled tubing portion; programming a second acoustic repeater to
receive information transmitted by the first acoustic repeater; and
receiving sensor information transmitted at the first operating
frequency by the first acoustic repeater and relayed by the second
acoustic repeater, the second acoustic repeater being coupled to
the coiled tubing portion uphole from the first acoustic
repeater.
8. The method of claim 7, wherein the second acoustic repeater
relays the information on a second operating frequency different
from the first operating frequency.
9. The method of claim 7, further comprising: coupling additional
acoustic repeaters to the coiled tubing portion responsive to a
determination that a wellbore condition has changed; and
transmitting synchronization instructions to the first acoustic
repeater, subsequent to the coupling or uncoupling, to instruct the
first acoustic repeater to transmit test information using another
frequency different from the first frequency.
10. The method of claim 7, further comprising: programming the
first acoustic repeater to use a modulation scheme for modulating
signals containing the sensor information.
11. The method of claim 10, wherein the modulation scheme includes
orthogonal frequency division multiplexing.
12. The method of claim 7, further comprising: receiving mud pulse
telemetry signals from the first acoustic repeater based on a
measurement by an accelerometer of the first acoustic repeater.
13. An apparatus, comprising: an acoustic transmitter; electrical
circuitry configured to drive the acoustic transmitter to generate
acoustic signals; an annular housing configured to enclose the
acoustic transmitter and to engage an outer circumference of a
section of coiled tubing; and a receiver.
14. The apparatus of claim 13, wherein the acoustic transmitter
includes a flexible piezoelectric actuator.
15. The apparatus of claim 13, wherein the electrical circuitry is
enclosed in the annular housing.
16. The apparatus of claim 15, further comprising additional
electrical circuitry enclosed in another annular housing separate
from the annular housing, the additional electrical circuitry
including one or more of a transducer interface board, a digital
signal processing board, or a gamma board.
17. The apparatus of claim 16, wherein the annular housing has an
outer diameter larger than an inner diameter of a stripper packer
assembly.
18. The apparatus of claim 13, further comprising a flexible
battery element.
19. The apparatus of claim 18, wherein the flexible battery element
includes a plurality of flexible battery portions.
20. The apparatus of claim 19, wherein a battery portion of the
plurality of battery portions is enclosed in a second annular
housing different from the annular housing.
Description
BACKGROUND
[0001] Tubing, such as coiled tubing, is a natural acoustic
waveguide that can serve as a telemetry channel to establish
bidirectional communication between surface operators and downhole
sensors and tools in a subterranean well system. An acoustic
telemetry system that operates on coiled tubing can include a
single transmitter at the well system bottom hole assembly (BHA)
and a receiver at the surface. For operations in extended and/or
horizontal wells, however, the telemetry signal from the
transmitter can be adversely attenuated.
[0002] Further, as coiled tubing is tripped into a well, it is
commonly passed through a stripper packer to maintain well
pressure. It may be difficult to use a conventional acoustic
repeater to mitigate signal attenuation, because the combination of
such a repeater and the coiled tubing may not fit through the
stripper packer annulus while maintaining the well seal at the
surface.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] FIG. 1 illustrates an example coiled tube system including
multiple acoustic repeaters in accordance with some
embodiments.
[0004] FIG. 2 illustrates a front view of an example acoustic
repeater in accordance with some embodiments.
[0005] FIG. 3 illustrates a section view of an example acoustic
repeater in accordance with some embodiments.
[0006] FIG. 4 illustrates a section view of an example modular
acoustic repeater in accordance with some embodiments.
[0007] FIG. 5 is a schematic diagram of an example electrical
system for an acoustic repeater for coiled tube telemetry in
accordance with some embodiments.
[0008] FIG. 6 illustrates an example data frame structure for data
transmitted by the acoustic repeater in accordance with some
embodiments.
[0009] FIG. 7 is a flow diagram for data transmission by the
acoustic repeater in accordance with some embodiments.
[0010] FIG. 8 is a flow diagram for data reception by the surface
system in accordance with some embodiments.
[0011] FIG. 9 is a flow chart illustrating a training and
synchronization method in accordance with some embodiments.
[0012] FIG. 10 illustrates a single hop relay mode for acoustic
repeater communication in accordance with some embodiments.
[0013] FIG. 11 illustrates a multi-hop relay mode for acoustic
repeater communication in accordance with some embodiments.
[0014] FIG. 12 is a flowchart illustrating a method for providing
communication between acoustic repeaters and a surface system in
accordance with some embodiments.
DETAILED DESCRIPTION
[0015] To address some of the challenges described above, as well
as others, systems, apparatus, and methods are described herein for
using acoustic telemetry repeaters in a subterranean well system
that employs coiled tubing. The acoustic repeaters may comprise a
relatively thin, hinged annular housing, which can be coupled about
the circumference of the coiled tubing before the stripper packer
location along the tubing, as the tubing is tripped into a well.
The annular housing of the acoustic repeater is configured to be
concentric with the coiled tubing and symmetric about the
longitudinal axis of the coiled tubing. Concentricity and symmetry
combined with a relatively small radial thickness of the repeater
housing enables the repeater to be attached to the coiled tubing
before the tubing passes through the stripper packer into the well.
Concentricity can also enable coupling of the repeater without
creating discontinuities along the coiled tubing. When
discontinuities are created, pressure may leak out, defeating the
purpose of the stripper packer.
[0016] FIG. 1 illustrates a coiled tubing system (CTS) 10 including
a reel 12, coiled tubing (CT) 14, a gooseneck 16, an injector head
18, and a stripper packer 20. CTS 10 is configured to trip the CT
14 into and out of a wellbore 22 within a casing 24. CTS 10 can be
used for a number of interventions, and, in some cases, for
production in subterranean wells.
[0017] In operation, injector head 18 draws CT 14 off of reel 12
and trips CT 14 into wellbore 22 through stripper packer 20.
Injector head 18 includes a mechanism that pushes CT 14 into and
pulls CT 14 out of wellbore 22. Injector head 18 operates in
conjunction with gooseneck 16, which acts as a curved guide beam
that threads CT 14 into injector head 18.
[0018] Below injector head 18 is stripper packer 20. Stripper
packer 20 can include rubber pack off members, which provide a seal
around casing 24 to isolate the pressure within the well from the
surface. Stripper packer 20 can be hydraulically opened and closed
to contain wellbore pressure. By applying hydraulic pressure at
stripper packer 20, an operator at the surface of the well is able
to compress rubber inserts and trip CT 14 into and out of wellbore
22 under pressure.
[0019] Although not shown in FIG. 1, CTS 10 can also include a
blowout preventer (BOP) below stripper packer 20. The BOP can
provide the ability to cut CT 14 and seal wellbore 22 (shear-blind)
to hold and seal around CT 14 (pipe-slip).
[0020] Example CTS 10 also includes multiple acoustic repeaters 26,
27 communicatively coupling a downhole transmitter (not shown) and
a surface receiver 28. The bottommost acoustic repeater 27 may
serve as the downhole transmitter. As described in more detail
below, acoustic repeaters 26 include a thin hinged annular housing,
which can be coupled about the circumference of CT 14 before
passing through stripper packer 20 as CT 14 is tripped into
wellbore 22. The annular housing of acoustic repeaters 26 is
configured to be concentric with CT 14 and symmetric about the
longitudinal axis of the tubing, however embodiments are not
limited thereto. Concentricity and symmetry combined with a
relatively small radial thickness of the housing can enable
acoustic repeaters 26 coupled to CT 14 to pass through stripper
packer 20. The ability to trip acoustic repeaters 26 into wellbore
22 through stripper packer 20 enables multiple repeaters to be
deployed downhole to mitigate signal attenuation in extended and/or
horizontal subterranean wells.
[0021] FIG. 2 depicts a front view of an example acoustic repeater
26 in accordance with some embodiments. Acoustic repeater 26
includes an annular housing 28. Annular housing 28 engages an outer
surface of CT 14 using, for example, hinges 30. While some example
acoustic repeaters 26 may have a relatively smooth outer surface
(e.g., spherical or ovoid as depicted in FIG. 2) that can be useful
in some embodiments to provide less leakage as the repeater 26, 27
passes through the strip packet 20 and into the well, other
acoustic repeaters 26, 27 can have other shapes, such as hexagonal
or rectangular shapes.
[0022] FIG. 3 depicts a section view of acoustic repeater 26 in
accordance with some embodiments. Annular housing 28 encloses
acoustic transmitter 32. Acoustic transmitter 32 can also serve as
an acoustic telemetry signal detector (e.g., a receiver). Acoustic
transmitter 32 can include a piezoelectric actuator 56 (FIG. 5).
The piezoelectric actuator 56 may be flexible to enable the
piezoelectric actuator 56 to be mounted in annular housing 28 that
is concentrically mounted about CT 14. The flexible piezoelectric
actuator 56 can include a micro-fiber composite (MFC) piezoelectric
actuator. Some references for MFC piezoelectric actuators quote
stress generation capabilities of +/-4000 psi at temperatures up to
180 degrees Celsius. Acoustic transmitter 32 can include a
plurality of flexible piezoelectric actuators (not shown in the
figures) arranged in a stack to actuate together. In this manner,
the actuators can generate acoustic signals with higher power than
the actuators could individually generate for transmission on CT
14.
[0023] Acoustic repeater 26 includes electrical circuitry 34.
Electrical circuitry 34 may include some of the elements described
in more detail below with respect to FIG. 5 (e.g., elements 44-50
and 54). Annular housing 28 may enclose electrical circuitry 34, or
electrical circuitry 34 may be enclosed in another separate annular
housing as described below with respect to FIG. 4. Electrical
circuitry 34 and acoustic transmitter 32 may be exposed to at least
some ambient pressure to permit a thinner annular housing 28
design. A thinner annular housing 28 design may enable further
reduction in the profile of acoustic repeater 26, as it appears
against the outer surface of the coiled tubing. A thinner annular
housing 28 may provide capability for insertion of additional
electrical circuitry 34 into annular housing 28.
[0024] Acoustic repeater 26 can include a flexible battery element
36. Flexible battery element 36 can include a plurality of flexible
battery portions, which may be housed in separate annular housing
(not shown in FIG. 3). Some references for flexible battery
elements quote a thickness of about 0.5 millimeters. Flexible
battery portions may be combined in series or parallel to achieve
greater power capacity in acoustic repeater 26. In some
embodiments, a flexible battery such as the FLEXION (Model SF
4823-25EC) lithium polymer battery made by Solicore corporation
(Lakeland, Fla., United States of America) can be used as the
flexible battery element 36.
[0025] Annular housing 28 can have an inner diameter about equal to
an outer diameter of CT 14 to prevent, for example, leakage or loss
of pressure between acoustic repeater 26 and CT 14. Some references
for CT quote outer diameters of about 1.2 inches to about 2.5
inches. Annular housing 28 may have an outer diameter larger than
an inner diameter of stripper packer 20. For example, annular
housing 28 may have an outer diameter larger than an inner diameter
of rubber inserts of stripper packer 20, described above with
respect to FIG. 1, yet small enough that the annual housing 28 does
not apply excessive stress to the rubber inserts or other elements
of stripper packer 20. Some references for the stripper packer 20
quote through-bore sizes of about 2.5 inches to about 5 inches.
[0026] FIG. 4 is a section view of acoustic repeater 26 arranged in
a modular design in accordance with some embodiments. Acoustic
repeater 26 can be separated into acoustic transmitter module 38,
electrical module 40, battery modules 42 and 44, or any combination
of modules thereof. Acoustic repeater 26 may be arranged in a
modular design to gain flexibility in acoustic repeater 26
configuration and for ease of maintenance. For example, operators
can add or remove additional battery modules 42, 44 to adjust to
changing energy requirements or change or add electrical modules 40
to adjust to changing requirements or replace non-functioning
modules of acoustic repeater 26. The modular design as shown in
FIG. 4 may also allow for a further reduced profile of the overall
acoustic repeater 26, with respect to the distance the repeater 26
rises above the outer surface of the coiled tubing.
[0027] FIG. 5 is a schematic diagram of an electrical system for
acoustic repeater 26 in accordance with some embodiments. Acoustic
repeaters 26 in accordance with this disclosure can be constructed
with a number of electronic components. The components described
with respect to FIG. 5 can include application-specific integrated
circuits (ASICs) or field programmable gated arrays (FPGAs)
designed for acoustic telemetry applications. Any of the components
shown in FIG. 5 may be housed separately or together in the annular
housing 28 (FIG. 2-3) or in one or more modules such as modules 38,
40, 42, 44 (FIG. 4) of the acoustic repeater 26. While some
components are shown in FIG. 5, acoustic repeater 26 may include
other components not shown in FIG. 5 or acoustic repeater 26 may
include a subset of the components shown in FIG. 5. Different
acoustic repeaters 26 of system 10 may have different subsets of
the components shown in FIG. 5.
[0028] In some embodiments, acoustic repeater 26 includes a
floating point digital signal processing (DSP) board 45. DSP board
45 is configured to receive digital data from, for example,
transducer interface board 46, gamma board 48, accelerometer 50 or
other data sources over communication links, for example an RS232
communication link or other data and control lines. Transducer
interface board 46 can receive and digitize data from casing collar
locator assembly 52, pressure transducers 54 or other sources
within or external to the acoustic repeater 26 assembly.
[0029] Accelerometer 50 can be a single-axis accelerometer or a
multi-axis accelerometer. For example, accelerometer 50 can be
multi-axis to provide increased precision or sensitivity with
respect to off-axis movement. Using accelerometer 50, acoustic
repeater 26 can also detect pressure pulses in the fluid within,
for example, CT 14 or elsewhere. In this way, acoustic repeater 26
can detect and relay mud pulse telemetry signals to surface system
28 (FIG. 1).
[0030] DSP board 45 compresses and packages the digital data and
transmits the data over a communication link to acoustic driver
board 54. Acoustic driver board 54 can be used to drive
piezoelectric stack 56 of acoustic transmitter 32, which generates
acoustic signals that are transmitted through CT 14 (FIG. 1-4). As
described above with respect to FIG. 3-4, acoustic repeater 26 can
include low profile batteries 36. Acoustic repeater 26 can also
include power supply boards 60 and 62.
[0031] Piezoelectric stack 56, another piezoelectric stack (not
shown in FIG. 5) or accelerometer 50 can also serve as a receiver
for acoustic repeater 26. In some embodiments, acoustic repeater 26
may include processor 58 that can be programmed to implement
different modulation schemes or trained to allow acoustic receiver
26 to receive and transmit on different frequencies as described
below with respect to FIG. 7. In some embodiments, acoustic
transmitter 32 can additionally or alternatively be programmed to
implement different modulation schemes or trained to allow acoustic
receiver 26 to receive and transmit on different frequencies.
[0032] FIG. 6 illustrates a generic data frame structure for a data
frame 64 transmitted by acoustic repeater 26 in accordance with
some embodiments. Data frame 64 can include preamble 66. Preamble
66 can include a pattern of data to allow acoustic repeaters 26,
surface system 28 or other devices to detect new incoming data
frames 64. Data frame 64 can include a data frame delimiter 68 to
denote the end of preamble 66. Data frame 64 can include a header
70. Header 70 can have identification information for data frame 64
such as type identifiers, sources of the data, etc. Data frame 64
can include a data payload 72, which can include sensor data or
other data being transmitted by acoustic repeater 26. Data frame 64
can include a cyclic redundancy check (CRC) 74 for detection of
corrupted data within data frame 64. Data frame 64 can include all
of fields 66, 68, 70, 72, and 74, or a subset of these fields, or
other fields (not shown in FIG. 6).
[0033] FIG. 7 is a flow diagram for data transmission by acoustic
repeater 26 in accordance with some embodiments. Functional
elements can be performed within acoustic repeater 26 by, for
example, DSP board 44, acoustic driver board 54, processor 58, or
acoustic transmitter 32.
[0034] Data to be transmitted 76 may be received at acoustic
transmitter 32, or as digital data received from the acoustic
driver board 54 and encoded as acoustic data in an encoder 78.
Circuitry, for example the circuitry of processor 58 or acoustic
transmitter 32, can perform modulation 80, preamble generation 82,
and header generation 84 to assemble 86 a data packet 64 (FIG. 6).
Acoustic transmitter 32 transmits the data packet 64. For example,
piezoelectric stack 56 of the acoustic transmitter 32 can launch an
acoustic signal into CT 14, which then acts as an acoustic
transmission medium.
[0035] Modulation 80 can be performed according to various
modulation schemes, including at least one of pulse position
modulation (PPM), on-off keying (OOK), frequency shift keying
(FSK), amplitude modulation (AM), and phase shift keying (PSK).
[0036] Modulation 80 can also be performed using orthogonal
frequency division multiplexing (OFDM), which is a method currently
used in some broadband communication applications for encoding
digital data on multiple carrier frequencies. With OFDM, a large
number of closely-spaced orthogonal sub-carrier signals are used to
carry the data on parallel channels. Each sub-carrier is modulated
with a modulation scheme such as, for example, FSK, at a low symbol
rate.
[0037] In some embodiments, OFDM may be used because the movement
of CT 14 can generate loud noises or other interference. OFDM can
reduce the impact of the noise at the surface, where signals may be
processed, thus improving reliability of some embodiments. OFDM can
reduce the impact of noise at least because OFDM's low symbol rate
can permit the use of a guard interval between symbols (e.g., a
representation of bits of data), thus reducing or eliminating
interference between symbols and, in turn, leading to a
signal-to-noise ratio improvement.
[0038] FIG. 8 is a flow diagram for data reception by surface
system 28 in accordance with some embodiments. In functional blocks
88, 90, 92, 94, and 96, surface system 28 can detect various
portions of a data frame 64 (FIG. 6). In functional block 94,
surface system 28 can perform a demodulation of the data signal
that was modulated by acoustic repeater 26. Surface system 28 can
perform error checking in functional block 96. Surface system 28
can then, in functional block 98, receive or prepare to receive a
next data frame 64.
[0039] FIG. 9 is a flow chart illustrating a training and
synchronization method 900 in accordance with some embodiments. The
training and synchronization method 900 can be performed when
acoustic repeaters 26, 27 are downhole. The training and
synchronization method 900 can be performed when the surface system
28 detects that downhole conditions have change, when additional
acoustic repeaters 26 are coupled to CT 14, or for other reasons.
Training and synchronization may be executed by processor 58 or
acoustic transmitter 32 of an acoustic repeater 26. The training
and synchronization method 900 can include functionalities 901
performed by surface system 28 and other functionalities 903
performed by acoustic repeaters 26, 27.
[0040] Surface system 28 can scan 902 a set of predetermined
frequency channels. Acoustic repeater 26 can transmit 904 on the
predetermined frequency channels. Surface system 28 can listen on
the predetermined frequency channels for these transmissions of
acoustic repeater 26 to identify 906 frequency channels that have
at least a threshold signal-to-noise ratio (SNR). Acoustic repeater
26 can wait 908 for a certain time duration after each
transmission, and then turn on 910 a listen mode to listen for a
channel identifier. If a channel identifier is received 912 from
the surface system 28, acoustic repeater 26 can send an
acknowledgement 914 and repeater identifier on the frequency
channel identified.
[0041] If surface system 28 receives 916 a response, including an
acknowledgement and an acoustic repeater identifier, to the surface
system 28's transmission of the channel identifier, the acoustic
repeater 26 can begin 918 transmissions on the determined frequency
channel, and surface system 28 can receive 920 data from acoustic
repeater 26 on the frequency channel. Otherwise, the
synchronization process may begin anew, or other channel
identifiers can be transmitted to the acoustic repeater 26.
[0042] Instead of or in addition to the process described above
with respect to FIG. 9, acoustic repeaters can be pre-programmed to
transmit on a given frequency channel. The frequency channel can be
adapted at a later time using the process described above with
respect to FIG. 9.
[0043] FIG. 10 illustrates an example single hop relay mode for
acoustic repeater 26 communication in accordance with some
embodiments. In the illustrative example, two frequency channels f1
and f2 are in use. At least one acoustic repeater 26 receives data
on frequency channel f1 and retransmits on frequency channel f2.
Adjacent acoustic repeaters 26 transmit on different frequency
channels f1, f2 to avoid signal contamination between the channels.
Frequency channels f1 and f2 may have been programmed into acoustic
repeaters 26 when the acoustic repeaters 26 were coupled to CT 14,
or at a later time during a synchronization process as described
above with respect to FIG. 9.
[0044] FIG. 11 illustrates a multi-hop relay mode for acoustic
repeater communication in accordance with some embodiments. In the
multi-hop relay mode, adjacent acoustic repeaters 26 still transmit
on different frequencies f1, f2. Each acoustic repeater 26 receives
and retransmits on a same frequency f1 or f2. Accordingly, when
data is transmitted on, for example, frequency f1, that data is not
received by a next adjacent acoustic repeater 26 but instead by a
subsequent acoustic repeater 26.
[0045] FIG. 12 is a flowchart illustrating an example method 1200
for providing communication between acoustic repeaters and a
surface system in accordance with some embodiments. Some elements
of method 1200 can be implemented by a surface receiver system 28
(FIG. 1).
[0046] Example method 1200 starts at block 1210 with programming a
first acoustic repeater 26 to transmit information at a first
operating frequency. In some embodiments, the programming of block
1210 proceeds similarly to the training and synchronization method
described above with respect to FIG. 9. In some embodiments, first
acoustic repeater 26 is preprogrammed to transmit at a first
operating frequency and later trained to transmit at different
operating frequencies as described above with respect to FIG. 9.
First acoustic repeater 26 can also be programmed to use a
modulation scheme for modulating signals containing the sensor
information. The modulation scheme can include OFDM, as described
above with respect to FIG. 7.
[0047] Example method 1200 continues at block 1220 with coupling
the first acoustic repeater 26 circumferentially around a CT 14
portion, an inner diameter of the first acoustic repeater 26 being
about equal to an outer diameter of the CT 14 portion.
[0048] Example method 1200 continues at block 1230 with programming
a second acoustic repeater 26 to receive information transmitted by
the first acoustic repeater 26.
[0049] Example method 1200 continues at block 1240 with receiving
sensor information transmitted at the first operating frequency by
the first acoustic repeater and relayed by the second acoustic
repeater. The second acoustic repeater is coupled to the coiled
tubing portion uphole from the first acoustic repeater. The second
acoustic repeater can relay the information on a second operating
frequency different from the first operating frequency.
[0050] Any number of additional acoustic repeaters 26 can be
coupled to CT 14. The number can be selected based on or in
response to a determination that a wellbore condition has changed.
If additional acoustic repeaters 26 are added, a synchronization
process as described above can be performed. This process can
include at least transmitting synchronization instructions to the
first acoustic repeater, subsequent to the coupling or uncoupling,
to instruct the first acoustic repeater to transmit test
information using another frequency different from the first
frequency.
[0051] Example method 1200 can include receiving mud pulse
telemetry signals from first acoustic repeater 26 based on a
measurement by an accelerometer 50 (FIG. 5) of first acoustic
repeater 26.
[0052] It should be noted that the methods described herein do not
have to be executed in the order described, or in any particular
order. Moreover, various activities described with respect to the
methods identified herein can be executed in iterative, serial, or
parallel fashion.
[0053] In summary, using the apparatus, systems, and methods
disclosed herein can provide surface systems with downhole sensor
data that uses the coiled tubing itself as an acoustic
communication channel between a series of acoustic repeaters. As a
result, real-time downhole conditions can be monitored during
CT-delivered services or processes, such as fracturing processes,
in extended or horizontal wells. At the same time, a surface system
can send commands, through the repeaters, to instruct downhole
tools to carry out desired operations. The low-profile of the
repeaters makes it possible to trip them into a well, through a
conventional stripper packer, without loss of pressure or other
problems, and without the need to modify existing surface
equipment.
[0054] The accompanying drawings that form a part hereof, show by
way of illustration, and not of limitation, specific embodiments in
which the subject matter may be practiced. The embodiments
illustrated are described in sufficient detail to enable those
skilled in the art to practice the teachings disclosed herein.
Other embodiments may be utilized and derived therefrom, such that
structural and logical substitutions and changes may be made
without departing from the scope of this disclosure. This Detailed
Description, therefore, is not to be taken in a limiting sense, and
the scope of various embodiments is defined only by the appended
claims, along with the full range of equivalents to which such
claims are entitled.
[0055] Such embodiments of the inventive subject matter may be
referred to herein, individually and/or collectively, by the term
"invention" merely for convenience and without intending to
voluntarily limit the scope of this application to any single
invention or inventive concept if more than one is in fact
disclosed. Thus, although specific embodiments have been
illustrated and described herein, it should be appreciated that any
arrangement calculated to achieve the same purpose may be
substituted for the specific embodiments shown. This disclosure is
intended to cover any and all adaptations or variations of various
embodiments. Combinations of the above embodiments, and other
embodiments not specifically described herein, will be apparent to
those of ordinary skill in the art upon reviewing the above
description.
* * * * *