Patent ID: 8248886

Claim:
A method for separating multiple-vibrator seismic data and reducing separation-related noise, said seismic data being recorded in an actual or simulated survey with N vibrators (N>1) operating simultaneously, with the number of sweeps per vibrator being fewer than N and the sweeps for each vibrator being different from the sweeps for the other vibrators in some manner, a sweep being defined as a period of continuous source energy radiation terminated by a listening time or other cessation of vibration for a time period at least as long as the two-way travel time of a seismic wave traveling from a vibrator down to a pre-selected deepest target of interest and back up to a seismic receiver, said method comprising: (a) separating the survey data to obtain a preliminary estimate of N seismograms, one per vibrator; and (b) adjusting the seismograms to match the survey data and to satisfy selected characteristics of noise-free seismograms, thereby producing N updated seismograms; wherein said adjusting comprises extracting that part of each seismogram that corresponds to signal, and using the extracted signal parts to generate an updated set of separated seismograms; and wherein the set of updated seismograms is generated by convolving each extracted signal part with its corresponding vibrator signature, then stacking all N results, subtracting that from the survey data, separating the result of that by vibrator, and for each vibrator adding that to the corresponding extracted signal part.