Dealing with the noise — Improving seismic whitening and seismic inversion workflows using frequency split structurally oriented filters

Summary This paper describes a seismic processing method that uses dip-steered filtering to improve the performance of subsequent seismic whitening and relative impedance inversion. Given favorable acquisition and processing parameters, the availability of high frequency signals is ultimately limited by poor Signal/Noise ratio (S/N) at high frequencies. Managing this noise is key to accessing the high frequency information. We show that although spatial filters applied to broadband seismic data mainly affect the central pass-band, a frequency splitting approach can specifically benefit targeted high frequency ranges in the spectrum. The dipsteered filters trade spatial resolution for increased S/N, but only in targeted frequency bands that are boosted during the subsequent whitening process. The S/N of the low frequencies can be improved using a similar process prior to acoustic impedance inversion. In a relative impedance inversion workflow, de-noising the low frequencies allows accurate inversion of thicker beds. Applying the technique prior to full-bandwidth inversion allows the use of lower seismic frequencies, and reduces reliance on a pre-existing background model. We can apply frequency split dip-steered filtering to prestack common offset volumes or partial stacks in a similar fashion. This delivers frequency balanced partial stacks with lower noise and increased resolution, ultimately leading to a reduction of offset dependent tuning and higher resolution elastic inversion products. Logs are not required for the process but independent well ties demonstrate the validity of the technique and are used to QC the products.