Interferometric seismic data processing for a towed marine survey

1. A method for processing seismic data, comprising:

receiving the seismic data acquired at two or more sensors on a towed marine survey;

regularizing the seismic data in space;

classifying the regularized seismic data below and equal to a predetermined frequency as low-frequency seismic data;

calculating, using a microprocessor, a set of low-frequency Green's functions using interferometry on the low-frequency seismic data;

processing high-frequency seismic data of the seismic data to create a set of high-frequency Green's functions at one or more source locations of the towed marine survey; and

merging the set of low-frequency Green's functions and the set of high-frequency Green's functions to create a set of broad-band Green's functions at the source locations.

2. The method of claim 1 , wherein regularizing the seismic data in space comprises organizing the seismic data based on one or more locations at which the seismic data was received.

3. The method of claim 1 , further comprising attenuating one or more noise modes in the low-frequency seismic data.

4. The method of claim 3 , wherein the noise modes comprise ambient noise present in a sea, one or more guided waves in the sea, swell noise of a sea surface, self noise due to one or more streamers, or combinations thereof.

5. The method of claim 1 , wherein the set of low-frequency Green's functions comprises one or more reflection seismic data based on one or more cross-correlations between the two or more sensors, and wherein one of the two or more sensors is configured as a source of the reflection seismic data.

6. The method of claim 1 , wherein the seismic data is classified using a low pass filter.

7. The method of claim 1 , further comprising generating a seismic image using the set of broad-band Green's functions.

8. The method of claim 7 , wherein generating the seismic image comprises:

producing a velocity model based on the set of broad-band Green's functions; and

imaging the set of high-frequency Green's functions using the velocity model.

9. The method of claim 8 , wherein imaging the set of high-frequency Green's functions comprises performing a reverse time migration using the velocity model and the set of high-frequency Green's functions.

10. The method of claim 1 , wherein the predetermined frequency is based on one or more sources and the sensors.

11. The method of claim 1 , wherein the seismic data are obtained through continuous recording for the seismic data and surrounding noise.

12. The method of claim 1 , further comprising re-sampling the low-frequency seismic data based on the predetermined frequency, and wherein the set of low-frequency Green's functions is calculated using interferometry on the re-sampled low-frequency seismic data.

13. The method of claim 12 , wherein the low-frequency seismic data are re-sampled according to a time interval and a spatial interval based on the predetermined frequency and a Nyquist sampling theorem.

14. The method of claim 13 , wherein the Nyquist sampling theorem specifies that the spatial interval is less than v*(2*f) −1 , where v is a frequency of noise in the recorded seismic data and f is the predetermined frequency.

15. A method for processing seismic data comprising:

receiving the seismic data acquired at two or more sensors on a towed marine survey;

regularizing the seismic data in space;

classifying the regularized seismic data above and equal to a predetermined frequency as high-frequency seismic data and below and equal to the predetermined frequency as low-frequency seismic data;

re-sampling the low-frequency seismic data based on the predetermined frequency;

attenuating one or more noise modes in the re-sampled seismic data;

calculating, using a microprocessor, a set of low-frequency Green's functions using interferometry on the attenuated seismic data;

processing the high-frequency seismic data of the seismic data to create a set of high-frequency Green's functions at one or more source locations of the towed marine survey; and

merging the set of low-frequency Green's functions and the set of high-frequency Green's functions to create a set of broad-band Green's functions at the source locations.

16. The method of claim 15 , wherein the predetermined frequency is based on one or more sources and the sensors.

17. The method of claim 15 , wherein the low-frequency seismic data are re-sampled according to a time interval and a spatial interval based on the predetermined frequency and a Nyquist sampling theorem.

18. The method of claim 15 , wherein the interferometry comprises using cross-correlation functions, deconvolution functions, summation functions, or combinations thereof.

19. A system, comprising:

a processor; and

a memory having program instructions configured to cause the processor to:

receive seismic data acquired by one or more seismic sensors on a towed marine survey;

regularize the seismic data in space;

classify the regularized seismic data below and equal to a predetermined frequency as low-frequency seismic data;

calculate a set of low-frequency Green's functions using interferometry on the low-frequency seismic data;

process high-frequency seismic data of the seismic data to create a set of high-frequency Green's functions at one or more source locations of the towed marine survey; and

merge the set of low-frequency Green's functions and the set of high-frequency Green's functions to create a set of broad-band Green's functions at the source locations; and

generate a seismic image using the set of broadband Green's functions.

20. The system of claim 19 , wherein the program instructions configured to cause the processor to regularize the seismic data comprises programs instructions configured to:

identify seismic data acquired by the seismic sensors at a position on the earth; and

concatenate the identified seismic data.