Apparatus and method for reducing noise in seismic data

• US 8,077,740 B2
• Filed: 01/31/2008
• Issued: 12/13/2011
• Est. Priority Date: 02/01/2007
• Status: Active Grant

• Current Assignee: INOVA Limited
• Original Assignee: INOVA Limited
• Inventors: Elder, Keith, Kooper, Steven, Feszthammer, Andras, Clayton, Donald E., Polk, Henry T.
• Primary Examiner(s): LY, ANH VU H
• Application Number:
  US12/023,725
• Publication Number:
  US 20080187006A1
• Time in Patent Office: 1,412 Days
• Field of Search: None
• US Class Current: 370/468
• CPC Class Codes: G01V 1/22 Transmitting seismic signals to recording or processing apparatus
• CPC Class Codes: G01V 1/247 Digital recording of seismic data, e.g. in acquisition units or nodes

Abstract

A method of acquiring seismic data. The method includes receiving seismic signals at one or more sensors; sampling the received seismic signals into a plurality of samples, each sample having a same bit length; arranging the samples into a plurality of packets; compressing the plurality of packets by varying a time interval between transmissions of at least some of the packets; and transmitting the compressed packets.

Claims

1. A method of acquiring seismic data, comprising:

receiving seismic signals at one or more sensors;

sampling the received seismic signals into a plurality of samples, each sample having a same bit length;

compressing at least some of the samples in selected packets before arranging such compressed samples into packets;

arranging the samples into a plurality of packets;

computing packet efficiency for a packet of the plurality of packets before computing the time intervals between the transmissions of the packets; and

transmitting the plurality of packets by varying time intervals between transmissions of the packets.

2. The method of claim 1 further comprising determining the time intervals between the transmissions of the packets using a random number generator.

3. The method of claim 1 further comprising using a time slot scheme for assigning the time intervals between the transmissions of the packets.

4. The method of claim 1, wherein the time intervals between the transmissions of the packets corresponds to a time slot assignment scheme.

5. The method of claim 1, wherein compressing samples comprises deleting selected bits from the at least some of the samples.

6. The method of claim 1 further comprising placing an indicator that identifies the compressed samples in the packets.

7. The method of claim 1, wherein transmitting the plurality of packets further comprises transmitting the packets via one of:

(i) land cable;

(ii) wirelessly;

(iii) an ocean bottom cable; and

(iv) a streamer cable that is in data communication with a central recording unit on a vessel.

8. The method of claim 1 further comprising receiving the transmitted packets at a remote unit and decompressing compressed packets.

9. The method of claim 8 further comprising processing the decompressed packets to obtain information about a subsurface structure.

10. The method of claim 1 further comprising varying the time intervals between transmissions of the packets in a manner that reduces coherent noise in the transmission of the packets.

11. A seismic data acquisition apparatus, comprising:

a circuit configured to receive seismic signals from a sensor and digitize the received seismic signals to provide a plurality of samples, each sample having a selected bit length;

a processor configured to;

compress at least some of the samples in selected packets before arranging such compressed samples into packets;

arrange the plurality of samples into a plurality of packets;

compute packet efficiency for a packet of the plurality of packets before computing the time intervals between the transmissions of the packets; and

transmit the plurality of packets by varying time intervals between the transmissions of the plurality of packets.

12. The seismic data acquisition apparatus of claim 11, wherein the processor is further configured to randomize the time intervals between the transmissions of the packets.

13. The seismic data acquisition apparatus of claim 11, wherein the processor is further configured to utilize a time slot scheme for the transmission of the packets.

14. The seismic data acquisition apparatus of claim 11, wherein the processor compresses the selected samples by deleting selected bits from such samples.

15. The seismic data acquisition apparatus of claim 11, wherein the processor is further configured to place an indicator in the packets that include compressed samples in order to identify the compressed samples.

16. The seismic data acquisition apparatus of claim 11 further comprising a remote unit in data communication with the processor, wherein the remote unit is configured to receive the transmitted packets;

decompress the received packets; and

store the decompressed packets.

17. The seismic data acquisition apparatus of claim 11, wherein the packets are transmitted via one of:

(i) a land cable;

(ii) wirelessly;

(iii) an ocean bottom cable; and

(iv) a streamer cable in data communication with a central recording unit on a vessel.

18. The seismic data acquisition apparatus of claim 11, wherein the processor is further configured to vary the time intervals between transmissions to reduce coherent noise.

19. A method of acquiring seismic data, comprising:

receiving seismic signals at one or more sensors;

sampling the received seismic signals into a plurality of samples, each sample having a same bit length;

compressing at least some of the samples in selected packets before arranging such compressed samples into packets;

placing an indicator that identifies at least one of;

(i) a number of compressed samples, (ii) a number of bits in each sample, and (iii) a number of bits removed from each sample;

arranging the samples into a plurality of packets;

computing packet efficiency for a packet in the plurality of packets before computing the time intervals between the transmissions of the packets; and

transmitting the plurality of packets by varying time intervals between transmissions of the packets.

20. The method of claim 19 further comprising using a time slot scheme for assigning the time intervals between the transmissions of the packets.

21. The method of claim 19 further comprising determining the time intervals between the transmissions of the packets using a random number generator.

22. The method of claim 19 further comprising varying the time intervals between transmissions of the packets in a manner that reduces coherent noise in the transmission of the packets.