Impact of directional illumination control parameters on seismic signals
To improve quality of seismic signals, DICT (directional illumination control technique) of DVAS (the distributed vibrator array system) is developed. It explains DICT theory in seismic wave domain and states why DVAS can generate directional seismic wave with DICT. The property of directional seismic wave can be described with directional factor. From directional factor, some control parameters such as amount of vibrators, arrangement of DVAS and delay time play an important role in seismic wave directivity and reflected waves' SNR (signal signal-to-noise ratio). To study parameters of directional illumination system, receiving signals are simulated by numerical method. The results show that reflected wave' SNR can be improved with more vibrators and small space between adjacent source in the same line. When the amount and space of source are settled down, a long delay time can increase reflected wave' SNR in shallow lays and a short delay time can boost signal SNR in deep lays. It concludes that DICT is a better control method to achieve high SNR signals with proper parameters. Furthermore, it offers some rules on how to determine parameters.
ATTENUATING MULTIPLES FOR LOW SIGNAL-TO-NOISE RATIO SEISMIC DATA USING OPTIMAL BEAMFORMING
We present an optimal beamforming method and its application to attenuating multiple for low signal-to-noise (S/N) ratio seismic data,which is better than some popular techniques like f-k and Radon transformation.The key point of the method is updating the constraint in the optimal beamformer design by using adaptive beamformer with the quiescent weighted vector.The example of real data processing example shows that this optimal beamformer method has improved the minimum variance unbiased beamformer significantly in attenuating multiples for low folding and/or low S/N ratio data at small extra cost.
Garnitures mécaniques d'étanchéité
Keywords: etancheite ; mecanique Reference Record created on 2005-11-18, modified on 2016-08-08