Hybrid deblending method and apparatus

Abstract

Methods and devices for seismic data processing deblend seismic data gathered using simultaneous source acquisition by applying two different deblending techniques. The second deblending technique is applied to residual data obtained after applying the first deblending technique. At least one of these first and second deblending techniques uses a signal-to-noise map.

What is claimed is: 
     
         1 . A method for separating energies originating from two sources when surveying an underground formation, the method comprising:
 receiving input seismic data following simultaneous actuation of the two sources;   applying a first deblending technique, FDT, to the input seismic data, to calculate residual data;   applying a second deblending technique, SDT, to the residual data to generate deblended data; and   creating an image of the explored underground formation using the deblended data obtained by applying the FDT and the SDT,   wherein the FDT and the SDT are different techniques, each attenuating cross-talk noise.   
     
     
         2 . The method of  claim 1 , wherein the two sources are part of a same seismic survey or the two sources belong to different seismic surveys. 
     
     
         3 . The method of  claim 1 , wherein the FDT yields a signal model and a noise model, and the residual data is obtained by subtracting data calculated using the signal model and the noise model, from the seismic data. 
     
     
         4 . The method of  claim 1 , further comprising:
 generating a signal-to-noise map for the seismic data,   wherein the signal-to-noise map is used when applying the FDT and/or when applying the SDT.   
     
     
         5 . The method of  claim 4 , wherein the signal-to-noise map is generated by:
 computing a first dataset that is representative of signal energy;   computing a second dataset that is representative of noise energy; and   populating the signal-to-noise map with expected signal-to-noise ratios based on the first dataset and the second dataset.   
     
     
         6 . The method of  claim 1 , wherein the FDT includes:
 applying weights to the input seismic data;   denoising the input seismic data to obtain denoised data;   generating a signal model based on the denoised data;   creating a noise model; and   calculating the residual data by subtracting data calculated using the signal model and the noise model, from the input seismic data.   
     
     
         7 . The method of  claim 6 , wherein the applying of the weights includes:
 selecting traces found inside a pre-defined radius around a noisy trace identified based on the signal-to-noise ratio, and   weighting the selected traces with an inverse of their amplitude.   
     
     
         8 . The method of  claim 1 , wherein one of the FDT and the SDT is a guided impulsive denoising comprising:
 generating a signal-to-noise map for the seismic data;   selecting noisy regions using the signal-to-noise map; and   replacing data in the noisy regions using interpolated data.   
     
     
         9 . The method of  claim 1 , wherein generating the signal-to-noise map comprises:
 weighting traces within a receiver gather with an inverse of their amplitudes;   computing an envelope of the data based on the weighted traces;   generating blended envelope data using acquisition shooting times; and   populating the signal-to-noise map with predicted signal-to-noise ratios (SNR) based on a difference between the envelope of the data and the blended envelope data.   
     
     
         10 . A data processing apparatus for separating energies originating from two sources that explore an underground formation, the apparatus comprising:
 an interface configured to receive input seismic data gathered using simultaneous actuation of the two sources; and   a data processing unit configured
 to apply a first deblending technique, FDT, to the input seismic data, to calculate residual data; 
 to apply a second deblending technique, SDT, to the residual data to generate deblended data; and 
 to obtain an image of the explored underground formation using the deblended data obtained by applying the FDT and the SDT, 
   wherein the FDT and the SDT are different techniques, each attenuating cross-talk noise.   
     
     
         11 . The apparatus of  claim 10 , wherein the two sources are part of a same seismic survey or the two sources belong to different seismic surveys. 
     
     
         12 . The apparatus of  claim 10 , wherein the FDT yields a signal model and a noise model, and the data processing unit is further configured to obtain the residual data by subtracting data calculated using the signal model and the noise model, from the seismic data. 
     
     
         13 . The apparatus of  claim 10 , wherein the data processing unit is further configured to generate a signal-to-noise map and to use the signal-to-noise map when applying the FDT and/or when applying the SDT. 
     
     
         14 . The apparatus of  claim 13 , wherein the data processing unit generates the signal-to-noise map by:
 computing a first dataset that is representative of signal energy;   computing a second dataset that is representative of noise energy using the acquisition shooting times; and   populating the signal-to-noise map with estimated signal-to-noise ratios based on the first dataset and second dataset.   
     
     
         15 . The apparatus of  claim 10 , wherein the FDT includes:
 applying weights to the input seismic data;   denoising the input seismic data to obtain denoised data;   generating a signal model based on the denoised data;   creating a noise model using acquisition shooting times; and   calculating residual data by subtracting data calculated using the signal model and the noise model, from the input seismic data.   
     
     
         16 . The apparatus of  claim 15 , wherein applying the weights includes:
 selecting traces found inside a pre-defined radius around a noisy trace identified based on the signal-to-noise ratio, and   weighting the selected traces with an inverse of their amplitude.   
     
     
         17 . The apparatus of  claim 10 , wherein one of the FDT and the SDT is a guided impulsive denoising comprising:
 generating a signal-to-noise map for the seismic data;   selecting noisy regions using the signal-to-noise map; and   replacing data in the noisy regions using interpolated data.   
     
     
         18 . The apparatus of  claim 17 , wherein the data processing unit generates the signal-to-noise map by:
 weighting traces within a receiver gather with an inverse of their amplitudes;   computing an envelope of the data based on the weighted traces;   generating blended envelope data using acquisition shooting times; and   populating the signal-to-noise map with predicted signal-to-noise ratios (SNR) based on a difference between the envelope of the data and the blended envelope data.   
     
     
         19 . A non-transitory computer readable medium storing executable codes which, when executed on a computer, makes the computer perform a method for deblending seismic data obtained when surveying an underground formation with two sources, the method comprising:
 receiving input seismic data following simultaneous actuation of the two source acquisition;   applying a first deblending technique, FDT, to the input seismic data, to calculate residual data;   applying a second deblending technique, SDT, to the residual data to generate deblended data; and   creating an image of the explored underground formation using the deblended data obtained by applying the FDT and the SDT,   wherein the FDT and the SDT are different techniques, each attenuating cross-talk noise.   
     
     
         20 . The medium of  claim 19 , wherein the two sources are part of a same seismic survey or the two sources belong to different seismic surveys.