Method for continuous sweeping and separation of multiple seismic vibrators

A method of separating the seismic response for each of a plurality N of seismic vibrators operated simultaneously with continuous sweeps, said method comprising the steps of:

• (a) loading each vibrator with a unique continuous sweep signal consisting of M≧N segments, the ith segment being of the same duration for each vibrator, i=1, 2, . . . , M;
• (b) activating all vibrators and using at least one detector to detect and record the combined seismic response signals from all vibrators;
• (c) recording a vibrator motion record for each vibrator indicative of the signature of that vibrator;
• and
• (d) obtaining a processed seismic data record wherein the record of the combined seismic response signals from all vibrators has been processed by
• parsing the vibrator motion record for each vibrator into M shorter records, each shorter record coinciding in time with a sweep segment, and then
• padding the end of each shorter record sufficiently to extend its duration by substantially one listening time;
• forming an M×N matrix s whose element sij(t) is the padded shorter vibrator motion record as a function of time t for the ith vibrator and jth sweep segment;
• parsing the seismic data record from step (b) into M shorter records, each shorter record coinciding in time with a padded shorter record of vibrator motion;
• forming a vector {right arrow over (d)} of length M whose element di is the ith shorter data record;
• solving for Ej(f) the following system of M linear equations in N unknowns
• S{right arrow over (E)}={right arrow over (D)}
• where Sij(f) is the Fourier transform to the frequency (f) domain of sij(t) and Di(f) is the Fourier transform of di(t), where i=1, 2, . . . M and j=1, 2, . . . N;
• and
• inverse Fourier transforming the Ej(f) to yield ej(t).