COUPLED TIME-DISTANCE DEPENDENT SWEPT FREQUENCY SOURCE ACQUISITION DESIGN AND DATA DE-NOISING

• US 20120290214A1
• Filed: 05/10/2012
• Published: 11/15/2012
• Est. Priority Date: 05/13/2011
• Status: Active Grant

• Current Assignee: Saudi Arabian Oil Company (Government of Saudi Arabia)
• Original Assignee: Saudi Arabian Oil Company (Government of Saudi Arabia)
• Inventors: Huo, Shoudong, Xu, Hai, Pecholcs, Peter I.
• Granted Patent: US 9,513,389 B2
• Time in Patent Office: Days
• US Class Current: 702/16
• CPC Class Codes: G01V 1/005 with exploration systems emitting special signals, e.g. frequency swept signals, pulse sequences or slip sweep arrangements
• CPC Class Codes: G01V 1/28 Processing seismic data, e.g. for interpretation or for event detection G01V1/48 takes precedence

Abstract

Acquisition of data by managing crosstalk interference with sector designs and unique sweeps is conducted and the resultant data are processed in 3D common receiver domain to attenuate crosstalk noise while preserving the signals for high source and receiver density acquisition designs. High-amplitude spectral amplitudes are attenuated and inter-ensemble statics or structural time delays are applied to achieve optimum filter performance. If the spectral amplitudes have been attenuated to a level consistent with non-simultaneous acquisition, conventional surface consistent processing can be performed to correct for statics and amplitude variations. A 3-point filter in different frequency bands may then be applied to remove any remaining residual crosstalk noise.

Claims

1. A computer implemented method of processing data obtained from seismic surveys of subsurface formations with emission by multiple swept frequency seismic energy sources for reception as blended source records at seismic receiver arrays in sectors of an area of interest, comprising the steps of:

sorting the blended source records in the time-distance domain to a common gather;

forming common offset trace ensembles of the common gather sorts of the blended source records;

transforming the common trace ensembles from the time-distance domain to the frequency-space domain;

applying a filter to frequency samples of the traces in the frequency-space domain to form a signal spectral model;

transforming the filtered traces from the frequency-space domain to the time-distance domain; and

storing the transformed filtered traces as deblended common source records for the individual ones of the swept frequency seismic energy sources.

2. The computer implemented method of claim 1, further including the step of:

forming an output display of selected deblended source common source records.

3. The computer implemented method of claim 1, wherein the step of sorting comprises the step of:

sorting the blended source records in the time-distance domain to a common receiver gather.

4. The computer implemented method of claim 1, wherein the step of sorting comprises the step of:

sorting the blended source records in the time-distance domain to a common source gather.

5. The computer implemented method of claim 1, further including the step of:

applying threshold values to the traces of the signal spectral model prior to transforming the filtered traces from the frequency-space domain to the time-distance domain.

6. The computer implemented method of claim 1, wherein the step of applying a filter comprises applying a median filter.

7. The computer implemented method of claim 1, further including the step of:

sorting the filtered traces in the time-distance domain to common-offset ensembles.

8. A data processing system for processing data obtained from seismic surveys of subsurface formations with emission by multiple swept frequency seismic energy sources for reception as blended source records at seismic receiver arrays in sectors of an area of interest, the data processing system comprising:

a processor performing the steps of;

sorting the blended source records in the time-distance domain to a common gather;

forming common offset trace ensembles of the common gather sorts of the blended source records;

transforming the common trace ensembles from the time-distance domain to the frequency-space domain;

applying a filter to frequency samples of the traces in the frequency-space domain to form a signal spectral model;

transforming the filtered traces from the frequency-space domain to the time-distance domain; and

storing the transformed filtered traces as deblended common source records for the individual ones of the swept frequency seismic energy sources; and

a display forming an output display of selected deblended source common source records.

9. The data processing system of claim 8, wherein the processor in the step of sorting performs the step of sorting the blended source records in the time-distance domain to a common receiver gather.

10. The data processing system of claim 8, wherein the processor in the step of sorting performs the step of sorting the blended source records in the time-distance domain to a common source gather.

11. The data processing system of claim 8, wherein the processor further performs the step of:

applying threshold values to the traces of the signal spectral model prior to transforming the filtered traces from the frequency-space domain to the time-distance domain.

12. The data processing system of claim 8, wherein the processor in applying a filter applies a median filter.

13. The data processing system of claim 8, wherein the processor further performs the step of:

sorting the filtered traces in the time-distance domain to common-offset ensembles.

14. A data storage device having stored in a computer readable medium computer operable instructions for causing a data processing system in processing data obtained from seismic surveys of subsurface formations with emission by multiple swept frequency seismic energy sources for reception as blended source records at seismic receiver arrays in sectors of an area of interest, the data storage device containing instructions for causing the data processing system to perform the steps of:

sorting the blended source records in the time-distance domain to a common gather;

forming common offset trace ensembles of the common gather sorts of the blended source records;

transforming the common trace ensembles from the time-distance domain to the frequency-space domain;

applying a filter to frequency samples of the traces in the frequency-space domain to form a signal spectral model;

transforming the filtered traces from the frequency-space domain to the time-distance domain; and

storing the transformed filtered traces as deblended common source records for the individual ones of the swept frequency seismic energy sources.

15. The data storage device of claim 14, wherein the data processing system includes a display, and further including instructions causing the display to form an output display of selected deblended source common sources records.

16. The data storage device of claim 14, wherein the instructions cause the processor in performing the step of sorting to sort the blended source records in the time-distance domain to a common receiver gather.

17. The data storage device of claim 14, wherein the instructions cause the processor in performing the step of sorting to sort the blended source records in the time-distance domain to a common source gather.

18. The data storage device of claim 14, wherein the instructions further cause the processor to perform the step of:

applying threshold values to the traces of the signal spectral model prior to transforming the filtered traces from the frequency-space domain to the time-distance domain.

19. The data storage device of claim 14, wherein the instructions further cause the processor to perform the step of:

sorting the filtered traces in the time-distance domain to common-offset ensembles.

20. A method of land surveying of subsurface formations in an area of interest with emission by a plurality of survey fleets of a plurality of swept frequency seismic energy sources for reception as blended seismic records at a receiver spread of seismic energy receiver arrays in sectors of the area of interest, comprising the steps of:

locating the survey fleets in different individual sectors across separate source swaths outside the receiver spread;

performing linear frequency sweeps at frequencies for individual survey fleets at different frequency ranges in a common bandwidth from the frequency ranges in the common bandwidth of the other survey fleets;

performing the linear frequency sweeps for the sources in the individual survey fleets of the plurality of survey fleets for sweep lengths of different times from the other sources in the same individual survey fleet; and

forming a blended seismic record at the receiver spread of linear frequency sweeps from the concurrently operating survey fleets.

21. The method of claim 20, further including the step of:

maintaining time-distance rules between the survey fleets during the survey.

22. The method of claim 20, further including the step of:

maintaining minimum distance rules between the survey fleets during the survey.

23. The method of claim 20, wherein the linear frequency sweeps for the sources in the individual survey fleets of the plurality of survey fleets for sweep lengths of differ in time from the other sources in the same individual survey fleet by at least twice the two-way travel time to a subsurface formation of interest. times from the other sources in the same individual survey fleet.

24. The method of claim 20, wherein the linear frequency sweeps in the sectors of the survey are performed in near-simultaneous time.

25. The method of claim 20, wherein frequencies for the frequency sweeps in the common bandwidth for the survey fleets overlap in part.

26. The method of claim 20, wherein the linear frequency sweeps for the sources in a sector of the survey are an increasing sweep and the linear frequency sweeps of an adjacent sector are a decreasing sweep.