Autonomous seismic data acquisition unit

• US 7,660,201 B2
• Filed: 08/22/2006
• Issued: 02/09/2010
• Est. Priority Date: 08/22/2006
• Status: Expired due to Fees

• Current Assignee: Geophysical Technology, Inc.
• Original Assignee: Autoseis Inc. (Global Geophysical Services Incorporated)
• Inventors: Fleure, Thomas J., Walker, Larry
• Primary Examiner(s): Hughes; Scott A
• Application Number:
  US11/466,298
• Publication Number:
  US 20080049550A1
• Time in Patent Office: 1,267 Days
• Field of Search: 367/56, 367 77- 80, 367/50, 331 2- 3, 368/159
• US Class Current: 367/50
• CPC Class Codes: G01V 1/24 Recording seismic data
• CPC Class Codes: G01V 2200/12 Clock synchronization-related issues

Abstract

A method, apparatus and system for acquiring land seismic data includes acquiring seismic data with a first autonomous seismic data acquisition unit and a second autonomous seismic data acquisition unit wherein each acquisition unit comprises a plurality of digitally controlled temperature-compensated crystal oscillators. Oscillator-based timing signals are acquired that are associated with the plurality of digitally controlled temperature-compensated crystal oscillators and a time correction is determined to apply to the seismic data acquired with the first autonomous seismic data acquisition unit. The time correction is determined using the oscillator-based timing signals from the first and second autonomous seismic data acquisition units.

Claims

1. A method for acquiring seismic data comprising:

a) acquiring seismic data with a first autonomous seismic data acquisition unit and a second autonomous seismic data acquisition unit wherein each acquisition unit comprises a plurality of digitally controlled temperature-compensated crystal oscillators;

b) acquiring oscillator-based timing signals associated with the plurality of digitally controlled temperature-compensated crystal oscillators; and

c) determining a time correction to apply to the seismic data acquired with the first autonomous seismic data acquisition unit, the correction determined using the oscillator-based timing signals from the first and second autonomous seismic data acquisition units.

2. The method of claim 1 further comprising determining the time correction as a function of the relative time difference between a selected plurality of the oscillator-based timing signals from the first and second autonomous seismic data acquisition units.

3. The method of claim 1 further comprising applying the determined time correction value to the recorded seismic data.

4. The method of claim 3 further comprising merging corrected data from the first autonomous seismic data acquisition unit with data collected from a telemetry-based seismic data acquisition system.

5. The method of claim 1 further determining a relative time difference between the first autonomous seismic data acquisition unit and a telemetry-based seismic data acquisition system.

6. The method of claim 1 further comprising recording a reference timing signal from a reference clock on at least one of the autonomous seismic data acquisition units.

7. The method of claim 1 further comprising determining a time correction associated with the first autonomous seismic data acquisition units that is a function of one of:

i) the relative time difference between the plurality of digitally controlled temperature compensated crystal oscillators, ii) a long term time history of the plurality of digitally controlled temperature compensated crystal oscillators; and

iii) a temperature history of at least one of the plurality of digitally controlled temperature compensated crystal oscillators.

8. The method of claim 1 wherein the first autonomous seismic data acquisition unit further comprises removable media storage.

9. A method for recording seismic data comprising:

a) deploying a first and second autonomous seismic data acquisition unit for acquiring seismic signals;

b) deploying a plurality of digitally controlled temperature-compensated crystal oscillators with the first and second autonomous seismic data acquisition unit to generate oscillator-based timing signals;

c) using the oscillator-based timing signal to determine a time correction to apply to the seismic data acquired with the first autonomous seismic data acquisition unit based on the oscillator-based timing signals from the first and second autonomous seismic data acquisition units; and

d) applying the determined time correction to the seismic data.

10. The method of claim 9, further comprising:

a) recording the temperature in the first autonomous seismic data acquisition unit;

b) computing the determined time correction as a function of at least one of;

i) the recorded temperature, ii) the oscillator-based timing signals, and iii) a synchronizing-time signal from a master clock.

11. The method of claim 9, further comprising the steps of:

a) accessing a database of the long term historical performance of the digitally controlled temperature compensated crystal oscillators;

b) computing the determined time correction as a function of at least one of;

i) the recorded temperature, ii) the oscillator-based timing signals, iii) values from the historical database of digitally controlled temperature compensated crystal oscillator performance, and iv) a synchronizing-time signal from a master clock.

12. The method of claim 9 further comprising recording a synchronizing-time signal from a master clock on the first autonomous seismic data acquisition unit after deployment.

13. The method of claim 9 further comprising recording a synchronizing-time signal from a master clock on the first autonomous seismic data acquisition unit prior to deployment.

14. The method of claim 9 further comprising merging the corrected seismic data with seismic data acquired with a telemetry-based seismic system.

15. The method of claim 9 further comprising downloading the seismic data and the oscillator-based timing signals from the first autonomous seismic data acquisition unit to a data depository.