Heterogeneous downhole acoustic network

• US 10,708,869 B2
• Filed: 01/30/2017
• Issued: 07/07/2020
• Est. Priority Date: 01/30/2017
• Status: Active Grant

• Current Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Original Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Inventors: Croux, Arnaud, Kusuma, Julius, Vannuffelen, Stephane
• Primary Examiner(s): Orgad, Edan
• Assistant Examiner(s): Mansoury, Nourali
• Application Number:
  US15/419,544
• Publication Number:
  US 20180220380A1
• Time in Patent Office: 1,254 Days
• CPC Class Codes: E21B 47/14 using acoustic waves
• CPC Class Codes: H04B 2215/061 Reduction of burst noise, e.g. in TDMA systems
• CPC Class Codes: H04L 27/00 Modulated-carrier systems
• CPC Class Codes: H04L 5/0055 Physical resource allocation for ACK/NACK for physical mapping arrangements in ARQ protocols H04L1/1861
• CPC Class Codes: H04L 5/1469 using time-sharing
• CPC Class Codes: H04W 40/005 Routing actions in the presence of nodes in sleep or doze mode
• CPC Class Codes: H04W 52/244 Interferences in heterogeneous networks, e.g. among macro and femto or pico cells or other sector / system interference [OSI]
• CPC Class Codes: H04W 56/002 Mutual synchronization
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

An acoustic network is located in a formation traversed by a borehole having a pipe contained therein. The acoustic network includes a backbone network having a number of backbone modems engaging the pipe and acoustically communicating along the pipe using a first modulation technique. A number of end node modems acoustically communicate using a second modulation technique orthogonal to the first modulation technique. At least one of the backbone modems is a bridge hub modem that is coupled to both the backbone network and an end node modem and communicates with the backbone network using the first modulation technique and with the end node modem using the second modulation technique. The end node modems may have a hibernation mode defined by low energy usage with no transmission or receipt of data, and a transmission mode defined by transmission of data by the end node modem.

Claims

1. An acoustic network located in a formation traversed by a borehole having a pipe contained therein, the network comprising:

a backbone network having a plurality of backbone modems engaging the pipe and acoustically communicating along the pipe using a first modulation technique, wherein the backbone modems are acoustic modems, wherein the backbone modems comprise a first set of modems comprising an uplink network and a second set of modems comprising a downlink network, the first set of modems being interleaved with the second set of modems, and wherein the uplink network and the downlink network have orthogonal signaling schemes providing for simultaneous bidirectional communications without interference; and

a plurality of end node modems acoustically communicating using a second modulation technique orthogonal to the first modulation technique, wherein the end node modems are acoustic modems, wherein at least one of the backbone modems is a bridge hub modem that is coupled to both the backbone network and to at least two of the plurality of end node modems, wherein the bridge hub modem is an acoustic modem and communicates with the backbone network using the first modulation technique and with the at least one end node modem using the second modulation technique.

2. The acoustic network of claim 1, wherein the plurality of end node modems operate in a plurality of modes including (i) a hibernation mode defined by low energy usage with no transmission or receipt of data and (ii) a transmission (TX) mode defined by transmission of data by the end node modem.

3. The acoustic network of claim 2, wherein

(i) the backbone modems comprise transmitter and receiver electronics, a processor, a battery of a first size and first capacity,

(ii) the end node modems comprise a transmitter, a processor, and battery of a second size and second capacity, and

(iii) the battery of a first size and first capacity is larger in size and larger in capacity than the battery of a second size and second capacity.

4. The acoustic network of claim 2, wherein the first modulation technique and the second modulation technique utilize time division multiplexing.

5. The acoustic network of claim 2, wherein

(i) the plurality of end nodes modems form an end node network, and

(ii) the end node network uses a protocol where the plurality of end node modems enter the TX mode and transmit messages to the bridge hub modem whenever the plurality of end node modems have messages to transmit.

6. The acoustic network of claim 5, wherein the protocol includes a random duplication such that each of the end node modems after transmitting a message waits a period of time and then transmits the same message again to the bridge hub modem.

7. The acoustic network of claim 2, wherein the plurality of modes includes a reception (RX) mode defined by reception of data by the end modem.

8. The acoustic network of claim 7, wherein

(i) the plurality of end node modems form an end node network, and

(ii) the end node network uses a protocol with acknowledgement signaling where (a) each end node modem enters the TX mode and transmits messages to the bridge hub modem whenever that end node modem has a message to transmit, (b) the hub bridge modem sends an acknowledgement signal to the end node modem that has sent a message, and (c) if the end modem that has sent a message does not receive the acknowledgement, that end modem waits a random period of time and then transmits the same message again to the bridge hub modem.

9. The acoustic network of claim 7, wherein

(i) the plurality of end node modems form an end node network, and

(ii) the end node network uses a protocol with channel occupation checking where, each end node modem prior to sending a message determines whether another modem is sending a message, and, if so, that end node modem waits a period of time and determines again whether a different modem is sending a message, and if no messages are being sent by other end node modems, that end node modem enters the TX mode and transmits a message to the bridge hub modem.

10. The acoustic network of claim 7, wherein the plurality of end node modems form an end node network and the bridge hub modem sends a wakeup signal to the end node modems to cause the end node modems to exit a hibernation mode.

11. The acoustic network of claim 10, wherein the wakeup signal causes the end node modems to synchronize.

12. The acoustic network of claim 11, wherein, after the wakeup signal, the end node modems send messages to the bridge hub modem in a time division multiplexed manner.

13. The acoustic network of claim 10, wherein

(i) each the end node modem uses a core sequence of (a) hibernation followed by (b) a micro-wake state where the end node modem is able to determine whether or not the end node modem is receiving a wakeup signal, and

(ii) the core sequence repeated until the wakeup signal is received from the bridge hub modem.

14. The acoustic network of claim 13, wherein the micro-wake state has a first length of time and the hibernation state has a second length of time, the second length of time being greater than the first length of time.

15. The acoustic network of claim 14, wherein the wakeup signal has a length of time at least equal to a sum of the first length of time and the second length of time.

16. The acoustic network of claim 1, wherein the first modulation technique is at a first frequency band and the second modulation technique is at a second frequency band orthogonal to the first frequency band.

17. A method of communicating information acoustically between a surface of a formation and a downhole apparatus via an acoustic network located in the formation traversed by a borehole having a pipe contained therein, the method comprising:

providing (i) a backbone network having a plurality of backbone modems engaging the pipe and acoustically communicating along the pipe utilizing a first modulation technique and (ii) a plurality of end node modems acoustically communicating utilizing a second modulation technique orthogonal to the first modulation technique, wherein the backbone modems are acoustic modems, wherein at least one of the backbone modems is a bridge hub modem that is coupled to both the backbone network and to at least two of the plurality of end node modems, wherein the bridge hub modem is an acoustic modem and the end node modems are acoustic modems, wherein the backbone modems comprise a first set of modems comprising an uplink network and a second set of modems comprising a downlink network, the first set of modems being interleaved with the second set of modems, and wherein the uplink network and the downlink network have orthogonal signaling schemes providing for simultaneous bidirectional communications without interference;

sending an acoustic signal containing first information from an end node modem coupled to the downhole apparatus to the bridge hub modem using the second modulation technique; and

acoustically sending the first information from the bridge hub modem up the backbone network to the surface using the first modulation technique.

18. The method of claim 17, wherein

(i) the end node modems operate in a plurality of modes including a hibernation mode defined by low energy usage with no transmission or receipt of data and a transmit (TX) mode defined by transmission of data by the end node modem, and

(ii) the sending the first information from an end modem to the bridge hub modem comprises causing the end node modem to awaken from hibernation prior to transmitting.

19. The method of claim 18, wherein the causing the end modem to awaken comprises sending a wakeup signal from the bridge hub modem to the end node modem coupled to the downhole apparatus to cause that end node modem to exit its hibernation mode prior to the sending the first information.

20. The method of claim 19, wherein the plurality of end node modems form an end node network and the bridge hub modem sends a wakeup signal to the plurality of end node modems to cause the plurality of end node modems to exit a hibernation mode and to synchronize the plurality of end node modems.

21. The method of claim 20, wherein, after the wakeup signal, the plurality of end node modems send messages to the bridge hub modem in a time division multiplexed manner.

22. The method of claim 18, wherein

(i) the causing the end node modem to awaken comprises sending a wakeup signal from the downhole apparatus to the end node modem, and

(ii) the sending an acoustic signal containing the first information from an end node modem to the bridge hub modem using the second modulation technique comprises sending the acoustic signal on-demand.

23. The method of claim 22, wherein the sending an acoustic signal containing the first information from an end node modem to the bridge hub modem using the second modulation technique further comprises causing the end node modem to wait a period of time after the sending the acoustic signal on-demand, and then resending the acoustic signal.

24. The method of claim 22, wherein the sending an acoustic signal containing the first information from an end node modem to the bridge hub modem using the second modulation technique further comprises:

(i) causing the end node modem to await receipt of an acknowledgement signal from the hub, and

(ii) upon not receiving the acknowledgement signal, waiting a period of time after the sending the acoustic signal on-demand, and

(iii) then resending the acoustic signal.

25. The method of claim 17, further comprising:

sending an acoustic signal containing second information down the backbone network to the bridge hub modem using the first modulation technique; and

sending the second information from the bridge hub modem to the downhole apparatus via at least one of the end node modems using the second modulation technique.

26. A method according to claim 25, wherein

(i) the end node modems operate in a plurality of modes including a hibernation mode defined by low energy usage with no transmission or receipt of data and a receive (RX) mode defined by receipt and processing of data by the end node modem, and

(ii) the sending the second information from the bridge hub modem to the downhole apparatus comprises sending a wakeup signal from the bridge hub modem to an end node modem coupled to the downhole apparatus to cause the end node modem coupled to the downhole apparatus to exit its hibernation mode prior to the sending the second information.