Transmitter and receiver synchronization for wireless telemetry systems.

(54) Title: SYNCHRONIZATION OF TRANSMITTER AND RECEIVER FOR WIRELESS TELEMETRY SYSTEMS. (54) Title: TRANSMITTER AND RECEIVER SYNCHRONIZATION FOR WIRELESS TELEMETRY SYSTEMS.

(57) Summary

A method and system for transmitting data along a casing in a borehole is presented, comprising generating an acoustic signal using a transmitter at a first location in the casing, and receiving the acoustic signal at a receiver in a second location in the casing. The method and system further comprise: (i) generating the acoustic signal at the transmitter at a first frequency and bit rate; (ii) receive the acoustic signal on the first frequency at the receiver and try to synchronize the receiver on the first frequency, and (iiia) if the synchronization is successful, continue transmitting the acoustic signal in order to pass the data from the transmitter to the receiver; or (iiib) if synchronization is unsuccessful, adjust the signal frequency and / or bit rate and repeat steps (i) - (iii) based on the adjusted signal.

(57) Abstract

A method and system are presented fortransmitting data along tubing in a borehole, comprising generating an acoustic signal using a transmitter at a first location on the tubing, and receiving the acoustic signal at a receiver at a second location on the tubing. The method and system further comprise: (i) generating the acoustic signal at the transmitter at a first frequency and bit rate; (ii) receiving the acoustic signal at the first frequency at the receiver and attempting to synchronize the receiver at the first frequency, and (iiia) if the synchronization is successful, continuing to transmit the acoustic signal so as to pass the data from the transmitter to the receiver; or (iiib) if the synchronization is unsuccessful, adjusting the frequency and / or bit rate of the signal and repeating steps (i) - (iii) on the basis of the adjusted signal.

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PATENT TITLE No. 355706

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IMPI

TtlAl rt

Headlines):

Home:

Denomination:

Classification:

Inventor (s):

SERVICES PETROLIERS SCHLUMBERGER

42, rue Saint Dominique, F-75007, FRANCE

SYNCHRONIZATION OF TRANSMITTER AND WIRELESS TELEMETRY.

RECEIVER FOR SYSTEMS

CIP: CPC: GUILLA

E21B47 / 16; E2Í1B47 / 12; GÓ1V3 / 00 E21B47 / 16; € 2tB47 / 12¿ ''

UME MILLOT; ERWANhMMtfelAGER

Number:

MX / a / 2011/001901

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..... W ·

s.2009

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HoJtq: ','

-. 'i

Nú'fl. ro:

08162855.4

Póís;

EP

Validity: Twenty years

Expiration Date: August 21, 2QjZ9 Issue Date: April 27, 2018

The patent of referenet * ne &lt;Q¿jrga based on the y.5 »rt» la Lrttde the PrgpedM

In accordance with the aS || j ^^ tffe'the Law of the Prdpled ^ Mf ^ l ^ q ^ t the patent will be in force for twenty an ^ s ^ prerogables, counted from the date of submit the solidWintemiaciíwi and payment d ^ jrfrtlBs $ aa ^^^ fener viger ^ s irirWechos.

«Faith 'feS ¿faith V *' '*« · w, feS&gt; «»_{í (} 5®? rf '. „jfe ® X

Who subscribes to the present title lobato # ¡C99 fun dame nto en lo disJjuest ^ pori &amp; Sijiftiáiltb 6 ° fraccionas III y 7? ^ s 2-of the Lfey of Industrial Property (Official Gazette of the Federation (0.0 F.) 27/06Λ991, amended on ^ »1994, $ / 10¿f» S6, 26/12 /) 8 $ 7, . 1 ^ 5/1999, 01/26/2004, 06/16/2005, 01/25/2006, 06/05/2009, 06/01/2010, tWraWO. ^ Oe / jafor 27/0 | / 2012 ^ 0W «/ 2012yartíMÍ ^ °, 3yr ^ A &amp; ^^ á a), 4 ° and 12 'fractions I and III of the Regulations of the Mexican Institute CteisPrapiefcd ImbitrtafXSUJ.F. Kl2 (1999, * (Stofmadúrel 01φ7 / 5®®2, J®®? / 2004, 07/28/2004 and 7/09/2007); articles 1, 3, 4, 5, section V, subsection a ), · ··· ~ - · .. ..uasw »· · - * ·

12/27/1999, amended on 10/10/2002, 29/0 ^ 3004

Deputy Generals, Coordinator, Departmental Directors and other subaltexpos ^ of the Mlxits Institute 08/04/2004 and 09/13/2007). ,

Lili and 3ÜWse »W« S »« rgán eÍ * 3F®Íe1i '^ (Industrial.

¡X ^ Orstiti ^ Oí ^ ib ^ d of Industrial Property (DOF

.... .... '' “^ Atít ^ do that delegates powers to the Directors, Divisional Deputy Directors, Coordinators jH ^ Í2 / 1999, amended on 02/04/2000, 07/29/2004,

This letter is signed with an advanced electronic signature (FIEL), based on articles 7 BIS 2 of the Industrial Property Law; 3rd of its Regulations, and 1 section HI »2 section V, 26 BIS and 26 TER of the Agreement establishing the guidelines for the use of the Electronic Payment and Services Portal (PASE) of the Mexican Institute of Industrial Property, in the procedures indicated.

THE DIVISIONAL DIRECTOR OF PATENTS

NAHANNY CANAL REYES

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Original string:

NAHANNY MARISOL CANAL REYES | 00001000000403252793 | Tax Administration Service | 1695 || MX / 2013/35755 | MX / a / 2011/001901 | Patent title PCT | 1223 | GAGV | Pág (s) | Z8J + 8qSfhOfMOK8Cqqfd916 =

Digital stamp:

DRr¡6jn + hl7HX85e0E + 9mwXB9fE32c292tdFJjbah5k + flaVSGL3hBNru8en / ZojorU2cv / f7zT335z + H4Pym1nUS7

37zf1Eo4zx2ssOL6hxyN4ESW8plaFR77AEIyUy3yQ2rOOh7vWBMpbGMgXeleOuy / 7xR7tavL9TH1B6jN611WGhK4uc

149eKzJJuWfOSCSD6uDQPae3ApokBMkCslaL1 / Fx2KOe + PFVRtHLNOigmLDZs2D1UuT + lyX2wGVabc + pGorn027dH3K1QBKJJBKJQQBJQQQBDQBJQBQQNDQBJQBQJQNQ

Arenal No. 550. Floor 1, Pueblo Santa Marta Tepepan, Xochímilco, 16020, Mexico City.

(55) 53340700 www.gob.mx/impi

<img file="MX355706B_D0006.tif" />

MX / 2018/35755

SYNCHRONIZATION OF TRANSMITTER AND RECEIVER FOR

9ο //// / 0 /

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WIRELESS TELEMETRY

TECHNICAL FIELD

The present invention relates to telemetry systems for use with installations in oil and gas wells or the like. In particular, the present invention relates to synchronizing transmitters and receivers to transmit data and control signals between a location below a borehole and the surface, or between locations at the bottom of the bore.

antecedent art

One of the most difficult problems associated with any borehole is communicating measured data between one or more locations below a borehole and the surface, or between locations at the bottom of the bore. For example, in the oil and gas industry it is desirable to report the data generated from the bottom of the borehole to the surface during operations such as drilling, fracturing, and test of the well and drill rod; and during production operations such as the reservoir evaluation test, pressure and temperature monitoring. Communication is also desirable to transmit intelligence from the surface to the tools or instruments at the bottom of the bore to

IMPIAS

MEXICAN INSTITUTE OF PROPERTY _. ,, _,,, INDUSTRIAL carry out, control or modify the operations or parameters.

Accurate and reliable bottom-hole communication is particularly important when complex data comprising a set of measurements or instructions must be communicated, that is, when more than a single measurement or simple trigger signal has to be communicated. For complex data transmission it is often desirable to communicate encoded digital signals.

Downhole testing is traditionally done in a blind way: Downhole tools and detectors are deployed within a well at the end of a string or casing string for several days or weeks after which are recovered on the surface. During drillhole test operations, detectors can record measurements that will be used for interpretation once recovered at the surface. It is only after the test string or string of test liner tubes is retrieved from the bottom of the borehole that operators will know if the data is sufficient and not corrupted. Similarly when operating from the surface some of the bottom hole test tools, such as test valves, circulation valves, plug, samplers

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INSTITUTO MÍX.'CANO í'í or drilling loads, operators do not provide direct feedback from horramioni-ac- en ^q1 drilling end.

In this type of bottom hole test operations, the operator can greatly benefit from having two-way communication between the surface and the bottom of the hole. However, it may be difficult to provide such communication using a cable from within the string or chain of casing tubes; This limits the flow diameter and requires complex structures to route the cable from the inside to the outside of the casing. A cable within the casing is also an added complexity in the event of an emergency disconnection for a marine platform. The space outside the casing is limited and a cable can be easily damaged. Therefore a wireless telemetry system is preferred.

Various proposals have been made for wireless telemetry systems based on acoustic and / or electromagnetic communications. Examples of various aspects of such

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WO96 / 024751; WO92 / 06275;

WOOO / 77345; W007 / 095111.

Due to the repetitive structure of the used structure of the pipe system, the characteristic of acoustic propagation along the pipes is such that the frequency response of the channel is complex. Figure 13 shows the theoretical and experimental frequency response of a piping system structure comprising two pipes below the wave source and eight pipes above. The spectrum has numerous highs and lows that are difficult to predict in advance. Given the spectrum and the use of a mono-carrier modulation scheme, choosing a maximum for the carrier frequency of the transmitted modulated signal where the noise is inconsistent with the signal is advantageous in terms of signal-to-noise ratio. Choosing a carrier frequency around a locally flat, ie distortion-free, channel response is advantageous in maximizing the bit rate. In any case, choosing the transport frequency on site is a requirement, and the process of choosing the correct frequency can take time and computational resources and has to be as simple as it is »

EP1320659; EP1882811;

WO02 / 27139; W001 / 39412;

possible.

US 2006/0187755 by

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Robert Tingley describes a method and system for communicating data through a drill string by transmitting multiple data sets simultaneously at different frequencies. The reference of

Tingley tries to optimize the opportunity for successful receipt despite the acoustic behavior of the drill string, and thus avoid the problem of selecting a single frequency.

Furthermore, US 5,995,449 by Clark Robison et al., Describes a method and apparatus for communication in a sounding using acoustic signals. However, the disclosure of

<td>Robison</td><td>et</td><td>to the. , it means</td><td>specifically to a</td><td>apparatus</td><td>and</td>

<td>method</td><td>for</td><td>transmit waves</td><td>acoustic through the</td><td>liquid</td><td>of</td>

<td colspan="2">completion</td><td>as a means</td><td>transmission in</td><td>instead of</td><td>the</td>

<td>pipeline</td><td>of</td><td>coating or</td><td>string or string</td><td>tubes</td><td>of</td>

coating.

It is an object of the present invention to provide a system that enables automatic synchronization of transmitters and receivers over an appropriate frequency for the reliable transmission of data along the casing in a borehole.

BRIEF DESCRIPTION OF THE INVENTION

A first aspect of the present invention provides a method for transmitting data along other pipelines.

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1 / SutójfuAx. * · * · Λ casing in a borehole, comprising generating a modulated acoustic signal using a transmitter at a first location in the casing, and receiving the acoustic signal at a receiver at a second location in the casing; the method further comprising:

(i) generate the acoustic signal at the transmitter at a first frequency and bit rate;

(ii) receive the acoustic signal on the first frequency at the receiver and try to synchronize the receiver on the first frequency; and (iiia) if the synchronization is successful, continue transmitting the acoustic signal in order to pass the data from the transmitter to the receiver; or

<td>(iiib)</td><td>yes</td><td>timing</td><td>not</td><td>is successful, adjust the</td>

<td>frequency</td><td>me</td><td>bit rate</td><td>the</td><td>acoustic signal and repeat</td>

<td>the stages</td><td>(i)</td><td>- (iii) based on</td><td>the</td><td>adjusted signal.</td>

Preferably step (iiib) comprises adjusting the frequency to one of a predetermined set of frequencies.

The predetermined set of frequencies may comprise the first frequency and more than two additional frequencies, the method further comprising iterating steps (i) - (iii) through the set of frequencies until synchronization is successful.

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Stage (iiib) can also include iasjitts £ ar the rate: 7 /

D £ LAP i 'i

JNDUSTiüzL 'bit signal at a lower bit rate. In one embodiment, the step of adjusting the bit rate follows the frequency adjustment.

A preferred embodiment of the present invention further comprises retransmitting the data received by the receiver from the second location to a third location. This can be as an acoustic or electromagnetic signal.

A second aspect of the present invention provides a system for transmitting data along the casing in a borehole, comprising:

- a transmitter at a first location in the casing to generate an acoustic signal in the casing; and

- a receiver at a second location in the casing to receive the acoustic signal; wherein the transmitter is configured to transmit data on a first frequency and a bit rate; and the receiver is configured to try to synchronize on the first frequency, such that if synchronization is successful, the transmitter continues to transmit the signal in order to pass the data from the transmitter to the receiver; or if synchronization is unsuccessful, the transmitter transmits the signal with a set frequency and / or bit rate and the reggptox tries'iÁ ^ j., z * to synchronize based on the set signal.

The transmitter and receiver typically operate in accordance with the method according to the first aspect of the present invention.

Preferably, the system comprises an additional transmitter at the second location to send a signal to the transmitter at the first location to confirm synchronization.

A transmitter can be provided at the second location to transmit the signal to a third location as an acoustic or electromagnetic signal.

The transmitter and receiver are preferably both configured to synchronize to selected frequencies from a predetermined set of frequencies.

The transmitter can also be adjusted to decrease the bit rate of the transmitted signal in the event that the receiver fails to synchronize.

I

A third aspect of the present invention provides a method of demodulating a single-carrier acoustic signal representative of particular data, wherein the modulated acoustic signal is transmitted along the casing in a borehole, the method comprising stages of:

<img file="MX355706B_D0009.tif" />

-β- - »: L u.¹· (I) transmit an acoustic signal

JNDUS predetermined carrier frequency and bit rate from a transmitter located at a first location in the casing;

(ii) trying to synchronize the modulated acoustic signal at multiple predetermined frequencies at a receiver located at a second location in the casing; and (iiia) if synchronization is successful for one of the transmitted frequencies, decoding the data on the synchronized frequency and transmitting an acknowledgment signal on the synchronized frequency to the transmitter;

or (iiib) if synchronization is not successful for one of the transmitted frequencies, adjust the carrier frequency and / or bit rate, and repeat steps (i) - (iii) based on the adjusted modulated acoustic signal.

In accordance with an embodiment of the third aspect, step (iiia) may further comprise transmitting the modulated acoustic signal to a receiver located at a third location in the casing. In another preferred embodiment, step (iiib) may comprise adjusting the carrier frequency to one of a predetermined set of frequencies, and further the bit rate of the modulated acoustic signal may be adjusted to a lower bit rate -'-. The-/··

Ρ *. OR . The bit rate adjustment can continue to adjust the carrier frequency.

In accordance with another embodiment of the present invention, step (i) comprises transmitting a modulated acoustic signal at multiple predetermined carrier frequencies. Step (iiia) of this embodiment may further comprise selecting the best synchronized frequency to transmit an acknowledgment signal to the transmitter.

The predetermined conveyor frequency for each mode can be chosen from a frequency sweep at a predetermined time where at least one frequency is chosen based on the quality indicators determined on a receiver located in the casing.

More aspects, features, and advantages of the present disclosure will become apparent from the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

Certain embodiments of the present invention will now be described with reference to the accompanying drawings, where like reference numerals denote like elements, and:

Figure 1 shows a schematic view of an acoustic telemetry system according to an embodiment of the

<td colspan="5">present invention;</td><td rowspan="2">liF / eTe .; '' ··, · · - Uíí.a ... ii i. ·: .., íMObi '. ruAt a modem like</td><td rowspan="2">', I know</td>

<td>The</td><td>Figure</td><td>2 sample</td><td>a</td><td>schematic of</td>

<td>uses</td><td colspan="4">in accordance with the modality of the</td><td>Figure 1;</td><td></td>

<td>The</td><td>Figure</td><td>3 shows</td><td colspan="2">a variant of the</td><td>modality of</td><td>the</td>

<td>Figure</td><td> 1;</td><td></td><td></td><td></td><td></td><td></td>

<td>The</td><td>Figure</td><td>4 shows</td><td>a</td><td>hybrid system</td><td>telemetry</td><td>of</td>

<td>agreement</td><td>with a</td><td>modality</td><td>of</td><td colspan="2">the present invention;</td><td></td>

<td>The</td><td colspan="3">Figure 5 shows a</td><td colspan="2">schematic view of a modem;</td><td></td>

<td>The</td><td>Figure</td><td colspan="2">6 sample</td><td colspan="2">a detailed view of</td><td>a to</td>

<td colspan="2">installation in</td><td>the bottom</td><td>of</td><td>drilling</td><td>Which incorporates</td><td>the</td>

modem of Figure 5;

Figure 7 shows an embodiment of the modem assembly in accordance with an embodiment of the present invention;

Figure 8 shows an embodiment of the assembly of a repeater modem according to an embodiment of the present invention;

Figure 9 shows a dedicated modem device for mounting in accordance with an embodiment of the present invention;

Figures 10, 11, and 12 illustrate applications of a hybrid telemetry system in accordance with an embodiment of the present invention;

Figure 13 depicts a response to the acoustic frequency of a pipe structure;

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Figure 14 illustrates an S-flow diagram of a method -de · .- · ^ · ?, 1; · | according to an embodiment of the present invention; and

Figure 15 shows a flow diagram of a receiver architecture for use in an embodiment of the present invention.

DETAILED DESCRIPTION

The present invention is particularly applicable to test facilities as used in oil and gas wells or the like. Figure 1 shows a schematic view of such a system. Once the well has been drilled through a formation, the drill string can be used to test and determine various properties of the formation through which the well has been drilled. In the example of Figure 1, well 10 has been lined with a steel tubing 12 (lined hole) in the conventional manner, although similar systems can be used in uncoated (open hole) environments. To test formations, it is preferable to place the test apparatus in the well near the regions to be tested, in order to isolate sections or intervals of the well, and to transport fluids from the regions of interest to the surface. This is commonly done using a bonded tubular drill pipe, drill string, production casing pipe, or the like

<img file="MX355706B_D0010.tif" />

from equipment 16 at the wellhead at 'the surface (or the seabed in underwater environments) down into the well to the area of ​​interest. Wellhead equipment 16 may include anti-eruption devices and connections for fluid, power and data communication.

A plug 18 is positioned in casing 14 and can be actuated to seal the borehole around casing 14 in the region of interest. Several pieces of downhole test kit 20 are connected to casing 14 above or below plug 18. Such downhole kit 20 may include, but is not limited to: additional plugs ; testing valves;

circulation valves; chokes for the bottom of the perforation; heads of fire or explosion; TCP (pipeline borne driller) substructures or devices for lowering the drill barrel; samplers;

pressure gauges; flow meters at the bottom of the bore;

fluid analyzers at the bottom of the bore; and the like.

In the embodiment of Figure 1, a sampler 22 is located above the plug 18 and a testing valve 24 is located above the plug 18. The equipment

<img file="MX355706B_D0011.tif" />

IJ 1 V at the bottom of the bore connects to msun.ciRÓdero 2

IftryJ_ »), JaL the bottom of the bore which is mounted on a manometer conveyor 28 positioned between the sampler 22 and the test valve. Modem 26, also referred to as an acoustic transceiver or transducer, operates to allow electrical signals from equipment 20 to be converted to acoustic signals for transmission to the surface via casing 14, and to convert acoustic signals from control of the surface tool on electrical signals to operate equipment 20 at the bottom of the bore. The term data, as used herein, is intended to encompass control signals, tool status, and any variations thereof whether transmitted by digital or analog media.

Figure 2 shows a schematic of the modem 2 6 in more detail. The modem 26 comprises a housing 30 that supports a battery 32 or an electric piezo actuator that can be actuated to create an acoustic signal in the casing 14 when the modem 2 6 is mounted on the manometer conveyor 28. Modem 26 may also include an accelerometer 34 or electrical monitoring piezo detector 35 for receiving acoustic signals. Where the modem 26 is only required to act as a receiver, the electric piezo actuator 32 can be omitted. Transmitter electronics 36 and electronics

<img file="MX355706B_D0012.tif" />

they are also located in the housing 30 'and the power is supplied by means of a battery, such as a rechargeable lithium battery 40. Other types of power supply can also be used.

The transmitter electronics 36 are arranged to initially receive an electrical output signal from a detector 42, for example from equipment 20 at the bottom of the bore provided with an electrical or electro / mechanical interface. Such signals are typically digital signals that can be provided to a microcontroller 43 which modulates the signal in one of several known ways;

PSK, QPSK, QAM, and the like. The resulting modulated signal is amplified by either a linear or non-linear amplifier 44 and transmitted to the electric piezo cell 32 in order to generate an acoustic signal in the material of the casing 14.

The acoustic signal passing along the casing 14 as a longitudinal and / or flexural wave comprises a transport signal with applied modulation of the data received from the detectors 42. The acoustic signal typically has, but is not limited to, a frequency in the range of 1-10 kHz, preferably in the range of 2-5 kHz, and is configured to pass data at a rate of, but is not limited to, about to- \ tKDUiñÜÁL about 200 bps, preferably from about up to about 100 bps, and more preferably about 50 bps. The data rate is dependent on conditions such as noise level, conveyor frequency, and distance between repeaters. A preferred embodiment of the present invention is directed to a combination of a short jump acoustic telemetry system for transmitting data between a center located above the main plug 18 and a plurality of tools for the bottom of the bore and valves below and / or or above said shutter 18. Subsequently, the data and / or the control signals can be transmitted from the center to a surface module either by means of a plurality of repeaters as acoustic signals or by converting them into electromagnetic signals and transmitting directly to the top. The combination of a short jump acoustic telemetry system with a plurality of repeaters and / or the use of electromagnetic waves allows an improved data rate on existing systems. The system can be designed to transmit data at speeds as high as 200 bps. There are other advantages of the present system.

The electronic systems 38 of the receiver are arranged

OR:

, IN to receive the acoustic signal that passes to 'casing 14 produced by the electronic systems of the transmitter of another modem. The receiver electronics 38 are capable of converting the acoustic signal into an electrical signal. In a preferred embodiment, the acoustic signal that passes along the casing pipe 14 excites the electrical piezo cell 32 in order to generate an electrical output signal (voltage); however, it is contemplated that the acoustic signal may drive an accelerometer 34 or an additional electrical piezo cell 35 in order to generate an electrical output signal (voltage). This signal is essentially an analog signal that carries digital information. The analog signal is applied to a signal conditioner 48, which operates to filter / condition the analog signal to be digitized by a 50 A / D converter (analog to digital). The A / D converter 50 provides a digitized signal that can be applied to a micro-controller 52. Micro-controller 52 is preferably adapted to demodulate the digital signal to retrieve data provided by detector 42 connected to another modem, or provided on the surface. The type of signal processing depends on the modulation applied (ie PSK, QPSK, QAM, and the like).

The modem 26 can therefore operate to transmit

<img file="MX355706B_D0013.tif" />

Acoustic data signals from the equipment 20 at the bottom of the bore along the casing pipe 14. In this case, the electrical signals from the equipment 20 are applied to the transmitter electronics 36 (described above) which they operate to generate the acoustic signal. Modem 26 can also operate to receive acoustic control signals to be applied to equipment 20 at the bottom of the bore. In this case, the acoustic signals are demodulated by the electronic systems 38 of the receiver (described above), which operate to generate the electrical control signal that can be applied to the equipment 20.

To support the transmission of acoustic signals along the casing pipe 14 between the bottom location of the borehole and the surface, a number of modems 56a, 56b, etc., can be positioned along the pipeline. coating 14. These repeater modems 56a and 56b can operate to receive an acoustic signal generated in the casing 14 by a preceding modem and to amplify and retransmit the signal for further propagation throughout the drill string. The number and spacing of repeater modems 56a and 56b will depend on the particular installation selected, for example on the distance the signal must travel. A typical spacing between the modefftSfgyg ^ -about ^ 1,000 ft (304.8 meters), but can be much more or less to accommodate all possible test tool configurations. By acting as a repeater, the acoustic signal is received and processed by the receiver electronics 38 and the output signal is provided to the microcontroller 52 of the transmitter electronics 36 and is used to drive the 32 piezo battery in the manner previously described. In this way, an acoustic signal can be passed between the surface and the bottom location of the bore in a series of short jumps.

The role of a repeater is to detect an incoming signal, decode it, interpret it, and subsequently broadcast it if required. In some implementations, the repeater does not decode the signal but merely amplifies the signal (and noise). In this case, the repeater acts as a simple signal booster. However, this is not the preferred implementation selected for the wireless telemetry systems of the present invention.

Repeaters are positioned along the string or casing pipe / string. A repeater will either continuously listen to any incoming signal or can listen from time to time.

Ιί / * '/&gt; 3ϊ

Wireless acoustic signals,^TÍMÍLÍi ^ 'aa3ég&gt; *^;W^and«

WDU £ T? JAL transport commands propagate in the transmission medium (casing) in an omni-directional manner, ie up and down. It is not necessary for the modem to know if the acoustic signal comes from another repeater from above or below. The message address is preferably embedded in the message itself. Each message contains multiple network addresses: the address of the transmitter (last and / or first transmitter) and the address of the destination modem at least. Based on the addresses embedded in the messages, the repeater will interpret the message and construct a new message with updated information regarding the transmitter and destination addresses. Messages will be transmitted from repeaters to repeaters and will be slightly modified to include new network addresses.

Referring again to Figure 1, a surface modem 58 is provided at wellhead 16 which provides a connection between casing pipe 14 and a data cable or wireless connection 60 to a control system 62 that can receive equipment data 20 at the bottom of the borehole and provide the control signals for its operation.

In the Figure 1 mode, the acoustic telemetry system is used to provide communication between the

1......

.L. ...

surface and bottom location of per &amp; usation. The.

¡ÍS t'bLlZdfL '&gt; * Figure 3 shows another modality in which ~ acoustic telemetry is used for communication between tools in the multi-zone test. In this case, two zones A, B of the well are isolated by means of shutters 18a, 18b. The team

Test 20a, 20b is located in each isolated zone A, B with corresponding modems 26a, 26b being provided in each case. Operation of the 26a, 26b modems allows the equipment

20a, 20b in each zone communicate with each other as well as allow communication from the surface with control and data signals in the manner described above.

Figure 4 shows an embodiment of the present invention with a hybrid telemetry system. The test facility shown in Figure 4 comprises a lower section 64 corresponding to that described above in relation to Figures 1 and 3. As before, the equipment 66 at the bottom of the bore and the plug (s) 68 are provided with 70 acoustic modems. However, in this case, the upper modem 72 differs in that the signals are converted between acoustic and electromagnetic formats. Figure 5 shows a schematic of the modem 72. The electronic systems 74, 76 of the acoustic transmitter and receiver correspond essentially to those described previously in relation to Figure 2, receiving and emitting signals

<img file="MX355706B_D0014.tif" />

acoustic by accelerometers).

source of

Also stacks 32 show piezo ef ^ Slrfiidas ,, Je 'UJi

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78, 80 of the electromagnetic (EM) receiver and transmitter, each having an associated micro-controller 82, 84; however, it should be appreciated that the EM receiver and transmitter electronics 78, 80 can also share a single micro-controller. A typical EM signal will typically be a digital signal in the 0.25 range

Hz to about 8 Hz, and more preferably around 1 Hz. This signal is received by the receiver electronics 78 and passed to an associated micro-controller 82. Data from microcontroller 82 can be passed to microcontroller 86 of the acoustic receiver and to microcontroller 88 of the acoustic transmitter where they are used to drive the signal from the acoustic transmitter in the manner described above. Likewise, the acoustic signal received at the receiver micro-controller 86 can also be passed to the EM receiver micro-controller 82 and subsequently to the EM transmitter micro-controller 84 where it is used to drive an antenna of the EM transmitter to create the digital EM signal that can be transmitted along the well to the surface. In an alternative embodiment (not shown), the acoustic transmitter and receiver electronics 74, 76 may share a single micro-controller

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Adapted to modulate and demodulate the corresponding j ['g [igital \ ító EM transceiver signal (not shown) can be provided on the surface for connection to a control system.

Figure 6 shows a more detailed view of a downhole installation where the modem is part of a downhole center 90 that can be used to provide short hop acoustic X telemetry with the various tools. 20 at the bottom of the bore (eg test and circulation valves (i), flowmeter (ii), fluid analyzer (iii) and plug (iv), and other tools under the plug (iv)), and long jump telemetry and EM to the surface. It should be understood that while not shown, the EM telemetry signal can be transmitted further down the hole to another center at the bottom of the hole or tools at the bottom of the hole.

Figure 7 shows how a modem 92 can be mounted on the equipment at the bottom of the bore. In the case shown, modem 92 is located in a common housing 94 with a manometer 96, although other housing and equipment may be used. Housing 94 is positioned in a recess 97 on the outside of a section of casing pipe 98 provided for such equipment and is commonly referred to as a manometer conveyor 97, ^ © s-íc'iórietí ^^ l, ^, · 2 J. .. .... £. .,. £) -ArJ ^ctlsdujVíual securely housed 94 in gauge conveyor 97, the acoustic signal can be coupled to casing 98. Typically, each piece of equipment at the bottom of the bore will have its own modem to provide the short jump acoustic signals, either for transmission via the center and long jump EM telemetry, or by acoustic long jump telemetry using repeater modems. The modem is protected with a hard cable in the detectors and actuators of the equipment in order to receive data and provide control signals. For example, where the equipment at the bottom of the bore comprises an operable device such as a plug, valve, or choke, or a detonation head of the bore barrel, the modem will be used to provide fix / unclamp, open / close signals. or shoot as appropriate. Sampling tools can be instructed to activate, pump, and so on; and detectors such as pressure and flow meters can transmit the recorded data to the surface. In most cases, the data will be recorded in the tool's memory and subsequently transmitted to the surface in batches. Also the tool settings can be stored in the tool memory and activated using

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the acoustic telemetry signal.

Figure 8 shows a way to mount the modem iui ι · ι.κιιιιι || ^ 4ομ

100 repeater in casing pipe 104. In this case, modem 100 is provided in an elongated housing 102 that is secured to the exterior of casing pipe 104 by clamps 106. Each modem 100 may be a self-contained installation, the pipe liner 104 providing both the physical support and the signal path.

Figure 9 shows an alternative embodiment for mounting repeater modem 108. In this case, the modem 108 is mounted on an external recess 110 of a dedicated tubular device 112 that can be installed in the drill string between adjacent sections of the drill rod string, or casing. Multiple modems can be mounted on the device for redundancy.

The preferred embodiment of the present invention comprises a two-way wireless communication system between the bottom of the perforation and the surface, which combines different modes of propagation of electromagnetic and acoustic waves. It can also include local cable communication, for example in the case of marine operations. The system takes advantage of the different technologies and combines them in a hybrid system, as represented in Figure 4.

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The purpose of combining the different ^¹- tipqs telemetry is to take advantage of the best characteristics of the different types of telemetry without having the limitations of some unique telemetry medium. Preferred applications for the embodiments of the present invention are for single zone and multiple zone well testing in terrestrial and marine environments. In the case of deep and ultra-deep marine environments, the communication link should be established between the floating platform (not shown) and equipment 66 at the bottom of the bore above and below the plug 68. The distance between the Drill train floor (above deck) and tools at the bottom of the borehole can be considerable, with up to 3km of seawater and 6km of formation / hole depth. There is a need to jump by means of a 'Long Jump' from the floor of the sounding train to the top of the equipment 66 at the bottom of the bore but then it is necessary to communicate locally between tools 66 (detectors and actuators) by means of of a 'short jump' within a zone or through several zones. The Salto Corto is used as a means of communication that supports distributed communication between the Salto Largo system and the individual tools that make up the 66 equipment at the bottom of the drilling, as well as between some of these tools within the facility in drilling. Short Jump communication supports: measurement data; temperature and gauge pressure; flow rates at the bottom of the bore; fluid properties; and the status of the tool at the bottom of the drill and activation commands, such as but not limited to:

IRDV; samplers (multiple); detonation heads (multiple); shutter release; other tools at the bottom of the bore (ie casing pipe tester, circulation valve, reversing valve); and the like.

All telemetry channels, whether wireless or not, have limitations from bandwidth, deployment, cost or reliability point of view. These are summarized in Figure 10.

At low frequency (~ 1 Hz), electromagnetic waves 120 propagate very far with little attenuation through formation 122. The greater the resistivity of the formation, the greater the range of wireless communication. The main advantages of electromagnetic wave communication relate to the long communication range, the independence of the flow conditions and the configuration of the string 124 or casing tube chain.

12 6 propagation of waves

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the string 124 or casing tube string can be made in such a way that each element of the system is small and power effective using high frequency (1 to 10 kHz) sonic waves. In this case, the main advantages of this type of acoustic wave communication are related to the small footprint and the medium data rate of wireless communication.

Optical or electrical cable technology 128 can provide the largest bandwidth and the most predictable communication channel. The power requirements for digital communication are also limited with electric or optical cable, compared to wireless telemetry systems. However, it is expensive and difficult to deploy the cable over several kilometers in a well (drillhole time, clamps, subsea tree) especially in the case of a temporary well installation, such as a well test.

In the case of single-zone or multiple-deep, deep-sea well testing, an appropriate topology for the hybrid communication system is to use a 128 (optical or electrical) cable from the sounding train floor to the seabed, a communication 120 electromagnetic wireless from the seabed to the top

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126 acoustic for communication of the local busbar.

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Another way to combine telemetry technologies is to parallel telemetry channels to improve system reliability through redundancy.

Figures 11 and 12 represent two cases where two or three communication channels are placed in parallel. In the

Figure 11, both electromagnetic wireless communication 120 and acoustic wireless communication 126 are used to transmit the data to the wellhead; and a cable

128 leads from the wellhead to the floor of the sounding train (not shown). In such configurations, common nodes 130 can be used for the different communication channels. Such nodes 130 essentially have functions similar to the center described above in relation to the

Figure 6. In Figure 12, the electromagnetic wireless communication 120 and acoustic wireless communication 126, and cable 128 are all provided to the location at the bottom of the bore, the acoustic wireless signal being used between the tools at the bottom of the hole. drilling. The selection of the particular communication channel used can be made at the surface or the bottom of the bore or at any common node between the channels. There are multiple paths for commands to go from the surface to the bottom of the bore and for which

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status go from the bottom of the hole to 1¿ surface. In the event of communication loss in a channel segment, an alternate path between two common nodes can be used.

A preferred embodiment of the present invention is based on a protocol in which a transmitter transmits a message (i.e. a control signal or data signal) on sequential frequencies belonging to a set S_F default of N frequencies until communication is successful. The mode preferably uses a receiver for parallel synchronization that simultaneously tries to demodulate the incoming signals transmitted by another tool / modem on frequencies S_F predetermined. The protocol is illustrated in Figure 14, which shows the

Sf to understand four frequencies Fi ~ F₄however, the predetermined set of frequencies can include many more or much less. A schematic of the parallel receiver is shown in Figure 15.

In the example illustrated in Figure 14, the transmitter initially transmits a signal on frequency F₄. The receiver tries to synchronize on multiple frequencies, FiF₄, but due to signal attenuation or distortion at this frequency, it is unable to synchronize with this signal at

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Fi so it does not return a recognition signal »i¿ewfei&gt; *

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INUUA «Auté transmitter. Upon starting to transmit on a given frequency, the transmitter initiates a timing routine. If no acknowledgment is received from the receiver within a predetermined time interval, the transmitter times and switches to the next frequency F₂. This process is repeated until an acknowledgment signal is received from the receiver on the same frequency, at which time the transmitter begins data transmission. An advantage of parallel synchronization illustrated in the example of

Figure 14 is the robustness of the process, and the removal of the need for frequency detection. In the example of the

Figure 14, synchronization occurs on frequency F3. It is contemplated that while one carrier frequency can be chosen for transmission from modem A to modem B, a different second carrier frequency can be chosen for transmission from modem B to modem

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The selection of an initial transmission frequency is preferably chosen from a set of frequencies based on past experience, but may also include an automatic mechanism at the start of the communication. This mechanism could consist of having all the transmitters transmitting frequency sweeps at a time

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mS? UTO MEXICANO DS THE default PROPERTY and all receivers in the string or^INeSS'éna casing tubes recording the incoming fiydlléK'd'Ta scans, subsequently determining the N best frequencies based on quality indicators such as amplitude, signal-to-noise ratio and flat spectrum variation.

Based on the spectral estimation of the communication channel in several cases and assuming that the set Sf is well chosen, it is very likely that there is at least one transport frequency between N (N being small, such as 4 or 5, but it can be much higher) with distortion and limited attenuation.

Figure 15 schematically shows the receiver architecture used for parallel synchronization. This corresponds to the signal processing preferably implemented in the micro-controller of the receiver's electronic systems, represented in Figure 2.

After the analog signal is digitized by the A / D converter, the resulting digitized signal is simultaneously demodulated by the micro-controller on the predetermined set of frequencies belonging to the Sf. The demodulation process preferably comprises two stages.

In the first stage, the micro-controller simultaneously tries to synchronize on the Sf frequencies. Where the incoming signal only has one frequency, the micro-controller tries;¹ ',' to synchronize on multiple frequencies, Jk ^ @_MHe &amp; 'can' ';

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INDUSTRIAL succeed in synchronizing on this signal frequency (the synchronized frequency). A synchronization process is based on correlation; where parallel synchronization consists of multiple simultaneous correlations. If synchronization is successful over the synchronized frequency, the start of the received signal is well known as well as its frequency. However, certain parameters can be estimated, such as phase and carrier frequency offset. In a second stage, the modulated signal is decoded and the data is recovered. Where the incoming signal is transmitted over multiple frequencies, the microcontroller selects the best frequency based on the highest correlation ratio and proceeds to decode the data on the best frequency.

In the example in Figure 14, all messages are transmitted at the same bit rate and the receiver tries to synchronize over the different frequencies at a single given bit rate. In another embodiment of the present invention, the bit rate can be varied. If the signal channel is unusually very loud and any of the transmitted signals are not recovered by the receiver, the system in Figure 14 will not work. To avoid this, the receiver can also be synchronized at a lower bit rate for each

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one of the frequencies belonging to the S_F. ·.

The transmitter will first try to transmit its messages at a high bit rate. In case of failure, it will transmit them in successively lower bit rates. Because the energy per bit becomes higher as the bit rate decreases, the energy per bit-to-noise ratio (Eb / N₀) is increased. Also, because the bandwidth of the signal is reduced, the received acoustic signal is less distorted by the channel. However this adds more complexity to the receiver and decreases the data rate, communication becomes more robust.

A particularly preferred embodiment of the present invention relates to multi-site testing (see

Figure 4). In this case, the well is isolated in separate zones by shutters 68, and one or more test tools are located in each zone. A modem is located in each zone and operates to send data to center 72 located above the upper shutter. In this case, the tools in each zone operate either independently or in synchronization. The signals from each zone are then transmitted to the center to be forwarded to the surface by any of the mechanisms described above. Also, surface control signals can be sent down through these mechanisms and forwarded to tools in

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each concert area.

in order to operate them either independently ^ S ^ T ^ ittéñt.ó iá.o ν ϊ ·;, .. .-. t

The signals can be transmitted to different

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, or eijú-.ú zones using multiple redundant telemetry paths (ie acoustic or EM) based on a predetermined set of communication related quality indicators. Based on the quality indicators, the best communication path can be selected.

Although only some embodiments of the present invention have been described in detail above, those of ordinary skill in the art will readily appreciate that many modifications are possible without materially departing from the teachings of the present invention. Consequently, such modifications are intended to be included within the scope of the present invention as defined in the claims.

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