Keeping the Data Quality of High Productivity Vibroseis Acquisitions Under Control

The popularity of the slip-sweep method for high productivity vibroseis acquisition is growing. However, for high values of the sweep length to slip-time ratio, that is for aggressive slip-sweep acquisitions, the harmonic contamination is severe. The first part of this paper presents a new technique for harmonic noise attenuation in aggressive slip-sweep acquisition. The second part introduces the dithered acquisition method in the framework of vibroseis acquisition. It is shown that after separation of the dithered records using a modeling and inversion technique, the quality of the final image (using the same number of shot gathers) is not affected by the dithered interference. The combination of dithered and slip-sweep acquisition is here proposed as a method to increase vibroseis productivity to values close to the limits obtainable when the vibrators sweep independently while keeping the interference noise due to simultaneous shooting under control.