The application of common offset wavenumber filtering on seismic data show improvements in isolating diffractions used to locate voids. F-k filtering is a simple method for attenuating primary waves and enhancing diffraction amplitudes. However, diffractions may also be attenuated where local apparent slopes are linear and within the reject fan of the f-K filter. We propose an alternative implementation of the f-k filter to better preserve diffraction amplitudes. When shot gathers are reordered to common offset records, diffractions are hyperbolic, whereas direct waves are nearly horizontal in settings with minimal or gradual lateral variability. A low-cut wavenumber filter attenuates the horizontal arrivals while retaining the diffraction amplitudes. Implementation of a static shift can further improve the alignment of direct arrivals and efficiency of the slope filter. This shift is trace dependent and is based on maximizing correlation coefficients to an averaged pilot trace. This alternative filtering technique in the common offset domain was compared to the conventional implementation, along with a variety of static shift parameters on data collected over a known tunnel. Slope filtering in the common offset domain better preserves diffraction signal and improves the overall signal-to-noise ratio on the final diffraction section.
Presentation Date: Monday, October 12, 2020
Session Start Time: 1:50 PM
Presentation Time: 3:05 PM
Location: Poster Station 5
Presentation Type: Poster
