Seismic survey method

A method of performing a 3-D seismic survey operation using (i) a plurality of sources comprising a vibrator or a group of vibrators, and (ii) an array of seismic sensors arranged within a survey area wherein each source emits a distinctive acoustic signal and each seismic sensor of the array is in a continuous state of readiness to detect reflected acoustic signals, the method comprising:

• (a) assigning vibrator points (VPs) to each of the sources;
• (b) independently moving each source to the assigned VPs where the source emits its distinctive acoustic signal independently in time of the emission of the distinctive acoustic signals of the other sources at their assigned VPs;
• (c) recording the emission time of the distinctive acoustic signal by each source at its assigned VPs together with the geographic position of the assigned VPs;
• (d) continuously listening for reflected acoustic signals using the array of seismic sensors and recording a time domain record of the reflected acoustic signals received by each seismic sensor of the array;
• wherein the reflected acoustic signals associated with the emission of a distinctive acoustic signal by a source at an assigned VP are determined by:
• (i) extracting the reflected acoustic signals associated with the emission of a distinctive signal from the time domain records for the seismic sensors of the array during a predetermined listening time associated with the emission of the distinctive acoustic signal by the source at the assigned VP;
• (ii) cross-correlating the extracted reflected acoustic signals with the distinctive emitted acoustic signal for the source at the assigned VP thereby eliminating weakly correlated signals and storing the correlated data in the form of time domain traces;
• and
• (iii) attenuating randomised cross-contamination in the cross-correlated extracted reflected acoustic signals from step (ii) using random noise attenuation techniques.