Process for separating data recorded during a continuous data acquisition seismic survey

1. A method for separating signals recorded by a seismic receiver and generated with at least first and second vibratory seismic sources, the method comprising:

receiving seismic data that includes data d recorded by the seismic receiver and data related to the first and second vibratory seismic sources, wherein the first and second vibratory sources are driven simultaneously and continuously with no listening time;

computing in a computing device a source separation matrix based on the data related to the first and second vibratory seismic sources;

calculating first and second earth impulse responses HA and HB corresponding to the first and second vibratory seismic sources, respectively, based on the source separation matrix and the data d recorded by the seismic receiver; and

separating the signals recorded by the seismic receiver based on the first and second earth impulse responses HA and HB such that signals originating from the first vibratory seismic source are disentangled from signals originating from the second vibratory seismic source,

wherein the first vibratory seismic source is located at a different depth than the second vibratory seismic source.

2. The method of claim 1 , further comprising:

parsing the data d recorded by the seismic receiver into smaller-length data segments; and

calculating the first and second earth impulse responses HA and HB based on the smaller-length data segments, the data d recorded by the seismic receiver, the data related to the first and second vibratory seismic sources and the source separation matrix,

wherein a length of the smaller-length data segments is equal to a pre-determined length of pseudorandom sequences that drive the first and second vibratory seismic sources.

3. The method of claim 1 , wherein the data related to the first and second vibratory seismic sources includes (i) first and second measured outputs U and V of the first and second vibratory seismic sources, respectively, and (ii) excitation signals A and B that drive the first and second vibratory seismic sources, respectively.

4. The method of claim 3 , further comprising:

cross-correlating the first and second measured outputs U and V with the excitation signals A and B; and

windowing with a first window function results of the cross-correlating step to form matrix vectors RUA, RUB, RVA, and RVB.

5. The method of claim 4 , further comprising:

applying a Fourier transform to the matrix vectors RUA, RUB, RVA, and RVB.

6. The method of claim 5 , wherein the source separation matrix is given by {D f ( S f ) T }, where

S

f

:=

(

FRUA

f

FRVA

f

FRUB

f

FRVB

f

)

,

D

f

:=

[

(

S

f

_

)

T

·

S

f

+

γ

·

I

]

-

1

,

I is the identity matrix, f is frequency index, γ is a constant, FRUA f , FRUB f , FRVA f , and FRVB f are the frequency domain elements of the Fourier transformed time domain matrix vectors rUA, rUB, rVA, rVB, and T is the matrix transpose operator.

7. The method of claim 5 , further comprising:

cross-correlating the data d recorded by the seismic receiver with the excitation signals A and B.

8. The method of claim 7 , further comprising:

windowing with a second window function results of the step of cross-correlating the data d recorded by the seismic receiver with the excitation signals A and B; and

applying a Fourier transform to results of the windowing step to obtain the Fourier transforms FRHA and FRHB of the windowed cross-correlations results.

9. The method of claim 8 , further comprising:

forming a matrix vector R that includes the Fourier transforms FRHA and FRHB.

10. The method of claim 9 , further comprising:

calculating an earth impulse response matrix H based on the source separation matrix and the matrix vector R, wherein the earth impulse response matrix H includes the earth impulse response HA of the first vibratory seismic source and the earth impulse response HB for the second vibratory seismic source.

11. The method of claim 10 , where the earth impulse response matrix H is the product of the source separation matrix and the matrix vector R.

12. The method of claim 1 , wherein the first vibratory seismic source is a low frequency source and the second vibratory seismic source is a high frequency source.

13. A computing device for separating signals recorded by a seismic receiver and generated with at least first and second vibratory seismic sources, the computing device comprising:

an interface for receiving seismic data that includes data d recorded by the seismic receiver and data related to the first and second vibratory seismic sources, wherein the first and second vibratory sources are driven simultaneously and continuously with no listening time for generating the data d; and

a processing unit connected to the interface and configured to,

compute a source separation matrix based on the data related to the first and second vibratory seismic sources;

calculate first and second earth impulse responses HA and HB corresponding to the first and second vibratory seismic sources, respectively, based on the source separation matrix and the data d recorded by the seismic receiver; and

separate the signals recorded by the seismic receiver based on the first and second earth impulse responses HA and HB such that signals originating from the first vibratory seismic source are disentangled from signals originating from the second vibratory seismic source,

wherein the first vibratory seismic source is located at a different depth than the second vibratory seismic source.

14. The computing device of claim 13 , further comprising:

parsing the data d recorded by the seismic receiver into smaller-length data segments; and

calculating the first and second earth impulse responses HA and HB based on the smaller-length data segments, the data d recorded by the seismic receiver, the data related to the first and second vibratory seismic sources and the source separation matrix,

wherein a length of the smaller-length data segments is equal to a pre-determined length of pseudorandom sequences that drive the first and second vibratory seismic sources.

15. The computing device of claim 13 , wherein the data related to the first and second vibratory seismic sources includes (i) first and second measured outputs U and V of the first and second vibratory seismic sources, respectively, and (ii) excitation signals A and B that drive the first and second vibratory seismic sources, respectively.

16. The computing device of claim 15 , wherein the processor is further configured to:

cross-correlate the first and second measured outputs U and V with the excitation signals A and B; and

window with a first window function results of the cross-correlating step to form matrix vectors RUA, RUB, RVA, and RVB.

17. The computing device of claim 16 , wherein the processor is further configured to:

apply a Fourier transform to the matrix vectors RUA, RUB, RVA, and RVB.

18. The computing device of claim 17 , wherein the source separation matrix is given by {D f ( S f ) T }, where

S

f

:=

(

FRUA

f

FRVA

f

FRUB

f

FRVB

f

)

,

D

f

:=

[

(

S

f

_

)

T

·

S

f

+

γ

·

I

]

-

1

,

I is the identity matrix, f is frequency index, γ is a constant, FRUA f , FRUB f , FRVA f , and FRVB f are the frequency domain elements of the Fourier transformed time domain matrix vectors rUA, rUB, rVA, rVB, and T is the matrix transpose operator.

19. The computing device of claim 17 , wherein the processor is further configured to:

cross-correlate the data d recorded by the seismic receiver with the excitation signals A and B;

window with a second window function results of the step of cross-correlating the data d recorded by the seismic receiver with the excitation signals A and B;

apply a Fourier transform to results of the windowing step to obtain the Fourier transforms FRHA and FRHB of the windowed cross-correlations results;

form a matrix vector R that includes the Fourier transforms FRHA and FRHB; and

calculate an earth impulse response matrix H based on the source separation matrix and the matrix vector R, wherein the earth impulse response matrix H includes the earth impulse response HA of the first vibratory seismic source and the earth impulse response HB for the second vibratory seismic source;

wherein the earth impulse response matrix H is the product of the source separation matrix and the matrix vector R.

20. A non-transitory computer readable medium including computer executable instructions, wherein the instructions, when executed by a processor, implement a method for separating signals recorded by a seismic receiver and generated with at least first and second vibratory seismic sources, the instructions comprising:

receiving seismic data that includes data d recorded by the seismic receiver and data related to the first and second vibratory seismic sources, wherein the first and second vibratory sources are driven simultaneously and continuously with no listening time;

computing in a computing device a source separation matrix based on the data related to the first and second vibratory seismic sources;

calculating first and second earth impulse responses HA and HB corresponding to the first and second vibratory seismic sources, respectively, based on the source separation matrix and the data d recorded by the seismic receiver; and

separating the signals recorded by the seismic receiver based on the first and second earth impulse responses HA and HB such that signals originating from the first vibratory seismic source are disentangled from signals originating from the second vibratory seismic source,

wherein the first vibratory seismic source is located at a different depth than the second vibratory seismic source.