Angle dependent surface multiple attenuation for two-component marine bottom sensor data

Abstract

A method of processing data that uses an angle dependent filter from two-component sensor data may allow for attenuation of free surface multiples. Typically, the sensors that are used to produce two-component ocean bottom sensor data are hydrophones and geophones. The method decomposes the recorded dual sensor data into upgoing and downgoing wavefields by combining the recorded pressure at the hydrophone with the vertical particle velocity from the geophone recorded at the ocean floor. Surface multiple attenuation is accomplished by application of an incident angle dependent deconvolution of the downgoing wavefield from the upgoing wavefield. The method uses an angle dependent filter to calibrate the geophone response so that the different coupling of the two instruments and associated noise are taken into account.

What is claimed is:  
     
         1 . A method for attenuation of multiples in marine seismic data, comprising: 
 creating seismic wavefields in a water environment, each created wavefield generated at a different location;    recording sensor readings from at least one sensor pair, wherein said at least one sensor pair comprises two different types of sensors, wherein said sensor readings are substantially a result of the created seismic wavefields, and wherein said sensor reading form a data set;    calculating angle dependent estimated values for upgoing and downgoing wavefields that generated the data set; and    generating an attenuated multiple data set using the estimated values for the upgoing and downgoing wavefields.    
     
     
         2 . The method as defined in  claim 1 , wherein the at least one sensor pair comprises a pressure sensor and a vertical particle velocity sensor.  
     
     
         3 . The method as defined in  claim 1 , wherein calculating angle dependent estimated values for upgoing and downgoing wavefields further comprises: 
 transforming the data set to a plane wave domain data set;    calibrating the plane wave domain data set using angle dependent calibration functions; and    using the calibrated plane wave domain set to calculate the estimated values for the angle dependent upgoing and downgoing wavefields.    
     
     
         4 . A system for generating attenuated multiple data for two-component marine seismic sensor data, comprising: 
 an acoustic energy source configured to generate an acoustic wavefield;    at least one sensor pair, the at least one sensor pair comprising two types of sensors configured to detect wavefields resulting from the generation of an acoustic wavefield by the acoustic energy source;    a recording system configured to separately record sensor readings from each sensor of the at least one sensor pair as data, the recording system configured to record the location of the acoustic energy source at a time when the acoustic energy source generates an acoustic wavefield, and said recording system configured to record the location of the at least one sensor pair; and    a data processor configured to analyze the data and produce the attenuated multiple data;    wherein the data processor calculates angle dependent estimated values of upgoing and downgoing wavefields that generated the data set, and wherein the data processor uses the estimated values of the upgoing and downgoing wavefields to generate the attenuated multiple data during use.    
     
     
         5 . A method of generating attenuated multiple data from two-component marine seismic data, comprising: 
 calculating angle dependent estimated values for upgoing wavefields and downgoing wavefields that generated the data; and    generating an attenuated multiple data set using the estimated values for the upgoing and downgoing wavefields.