Converted Wave AVO Inversion For Average Velocity Ratio And Shear Wave Reflection Coefficient

Li, Xiang Yang (University of Edinburgh) | Wei, Stephen (University of Edinburgh) | Chen, Tiansheng (SinoPec E&P Research Institute) | Ji, Yuxin (SinoPec E&P Research Institute)

OnePetro 

Summary

Using the empirical Gardner equation describing the relationship between density and compressional wave velocity, we propose converted wave reflection coefficient extreme attributes for AVO analysis and derive relations between the extreme position and amplitude, average velocity ratio across the interface, and shear wave reflection coefficient. The extreme position is a monotonically decreasing function of average velocity ratio, and the extreme amplitude is a function of average velocity ratio and shear wave reflection coefficient. For theoretical models, the average velocity ratio and shear wave reflection coefficient are inverted from the extreme position and amplitude obtained from fitting a power function to converted wave AVO curves. Shear wave reflection coefficient sections have clearer physical meaning than conventional converted wave stacked sections and establish the theoretical foundation for geological structural interpretation and event correlation. The method of inverting average velocity ratio and shear wave reflection coefficient from the extreme position and amplitude obtained from fitting a power function is applied to real CCP gathers.