Variable depth streamer srme

Abstract

Methods and systems for variable wavelet correction are described. A variable depth dataset is deghosted before presentation to a multiples prediction step of multiples elimination model. In another aspect, the multiples prediction is reghosted before presentation to and adaptive subtraction step of the multiples elimination model. A source-side zero-phasing signature can be applied before deghosting and a predefined gain can be applied in the low and high frequency sides as part of deghosting and reghosting to compensate for the squaring effect produced by convolving wavelets.

What is claimed is: 
     
         1 . A method, stored in a memory and executing on a processor, for correcting wavelet variations associated with a variable depth streamer configuration for seismic data collection, said method comprising:
 processing a recorded variable-depth datum pre-stack dataset, in a shot gather domain, by deghosting said pre-stack dataset wherein all multiples orders are processed; and   outputting a deghosted pre-stack dataset wherein said deghosted pre-stack dataset is normalized to a sea-surface datum and provided to a multiples elimination technique.   
     
     
         2 . The method of  claim 1 , further comprising a pre-stack reghosting of a multiples model from said multiples elimination technique, in said shot gather domain, wherein said multiples model generated from said sea-surface datum is applied to said recorded datum to output a reghosted variable depth pre-stack dataset. 
     
     
         3 . The method of  claim 2 , wherein a predefined gain is applied to low frequency and high frequency sides during said pre-stack reghosting. 
     
     
         4 . The method of  claim 1 , wherein a predefined gain is applied to low frequency and high frequency sides during said pre-stack deghosting. 
     
     
         5 . The method of  claim 1 , wherein a source-side zero-phasing designature is applied to said recorded datum pre-stack dataset prior to said deghosting. 
     
     
         6 . The method of  claim 5 , wherein said deghosted pre-stack dataset is input to a multiples prediction of a Surface Related Multiples Elimination (SRME) technique. 
     
     
         7 . The method of  claim 5 , wherein said deghosted pre-stack dataset is input to a multiples prediction of a Shallow Water Demultiple technique. 
     
     
         8 . The method of  claim 5 , wherein said deghosted pre-stack dataset is input to a multiples prediction of a Convolution Inter-bed multiples technique. 
     
     
         9 . The method of  claim 5 , wherein said deghosted pre-stack dataset is input to a multiples prediction of a Radon Demultiple technique. 
     
     
         10 . The method of  claim 5 , wherein said deghosted pre-stack dataset is input to a multiples prediction of a Tau-P Deconvolution technique. 
     
     
         11 . The method of  claim 1 , wherein said recorded datum pre-stack dataset and said deghosted pre-stack dataset is two-dimensional data. 
     
     
         12 . The method of  claim 1 , wherein said recorded datum pre-stack dataset and said deghosted pre-stack dataset is three-dimensional data. 
     
     
         13 . The method of  claim 2 , wherein said reghosted pre-stack dataset is input to an adaptive subtraction process of a demultiples model. 
     
     
         14 . A system for correcting wavelet variations associated with a variable-depth streamer configuration, said system comprising:
 a dataset containing a plurality of streamer variable-depth input trace data;   one or more processors configured to execute computer instructions and a memory configured to store said computer instructions wherein said computer instructions further comprise:
 a deghosting component for processing a recorded variable-depth datum pre-stack dataset, in a shot gather domain, wherein all multiples orders are processed; and 
 an output component for outputting a deghosted pre-stack dataset wherein said deghosted pre-stack dataset is normalized to a sea-surface datum and provided to a multiples elimination technique. 
   
     
     
         15 . The system of  claim 14 , further comprising a reghosting component for reghosting a multiples model, in said shot gather domain, wherein said multiples model is generated from said sea-surface datum and is applied to said recorded variable-depth datum for outputting a reghosted variable-depth pre-stack dataset. 
     
     
         16 . The system of  claim 14 , wherein said deghosting component further comprises applying a predefined gain to low frequency and high frequency sides. 
     
     
         17 . The system of  claim 15 , wherein said reghosting component further comprises applying a predefined gain to low frequency and high frequency sides. 
     
     
         18 . The system of  claim 16 , wherein said deghosting component further comprises applying a source-side zero-phasing designature to said recorded variable-depth datum pre-stack dataset before said deghosting. 
     
     
         19 . The system of  claim 14 , wherein said streamer variable-depth input trace data is two-dimensional data. 
     
     
         20 . The system of  claim 14 , wherein said streamer variable-depth input trace data is three-dimensional data.