A High-resolution Weighted Semblance for Dealing with AVO Phenomenon

Velocity analysis employs coherency measurement along a hyperbolic or non-hyperbolic trajectories time window to build velocity spectra. Accuracy and resolution are strictly related to the method of coherency measurements. Semblance has poor resolution velocity which affects its ability to distinguish distinct peaks. The problem of traditional semblance are two folds: low resolution and inability of handling AVO phenomenon. Although the AB semblance method can peak velocities in area with AVO anomaly, it has a lower resolution than conventional semblance. In this paper, we proposed a weighted AB semblance method that can handle the two problems simultaneously. We introduced new weighting functions to the AB semblance in order to enhance the resolution of velocity spectra in time and velocity axis. The first weighting function is defined based on the ratio between the first and second singular values of the time window in order to improve the resolution of velocity spectra in velocity axis. The second weighting function is based on the position of seismic wavelet in time window and can enhance the resolution of velocity spectra in time axis. We use both synthetic and field data examples to show the superior performance of the proposed approach over traditional approaches.