VP/VS from prestack multicomponent seismic data and automatic PS to PP time mapping
Osareni Christopher Ogiesoba, Robert R. Stewart
This paper discusses the development and application of a prestack method that scans for the average vertical velocity ratio (VP/VS) value, generally referred to as 0, and the stacking velocities of multicomponent seismic data using a converted-wave (PS) nonhyperbolic traveltime equation. The procedure entails computing semblance as a function of two variables namely, the PS stacking velocity VPS, and 0, with respect to the PS zero-offset time tps0. The results are displayed in 2D plots. We tested the procedure using numerical data sets and real data sets from the Blackfoot Field in Southern Alberta. We observed that the 0 values from the scanning method agree reasonably well with the 0 values from the well log of Well 09-08 located at the CDP location at which the analysis was performed. In addition, when these 0 estimates are used for PS-PP time mapping, the time difference between the computed and actual PP time at the target level is found to be 10 ms; being an error of less than 3%.