Deharmonics, a Method for Harmonic Noise Removal on Vibroseis Data

With the advent of slip sweeps to increase Vibroseis acquisition productivity, the need for harmonic noise removal became more critical to preserve the data quality compared to conventional “flip flop” vibroseis data. Several methods for harmonic noise attenuation are available such as HPVA, Jeffryes, Bagaini, Ziolkowski, Sicking et al. and others. Most of the methods are based on the recording of the vibrator ground force signal to design the operator. However, in some cases the signal is lost or not representative of the vibroseis array. Some of the methods require using uncorrelated data that implies handling of a large amount of data every day. We have successfully implemented a method to remove the harmonic noise without the ground force signal. The method is based on collapsing the harmonic noise by adding the pilot fundamental phase on a correlated record and subtracting the theoretical harmonic phase to be collapsed followed by a deterministic surgical edit of the first breaks. Transformation back to the original noise free correlated record is trivial by applying the inverse phase operation, which is adding the harmonic phase and subtracting the fundamental. The method is demonstrated with synthetic and real data from a slip sweep acquisition