AVO analysis using the VSP

Craig A. Coulombe, Robert R. Stewart, Michael J. Jones

A multioffset VSP geometry and 3-component processing flow have been developed to obtain true reflection coefficients from 3-component VSP data with the purpose of using the reflection coefficients for AVO analysis. The geometry and processing flow have been tested on synthetic data and found to recover the true reflection coefficients for a range of incidence angles. A multioffset field VSP survey was acquired for the analysis of the AVO response of a gas-bearing carbonate. 3- component processing of the data resulted in a good correlation between real and modeled P-P and P-S reflection coefficients. Single interface AVO analysis was found to be inadequate in describing the AVO behavior of the reflections from the top and the base of the gas-bearing carbonate zone, and full multilayer modeling was found to match the real data well.