Patent ID: 7684952
Filing Date: 2010-03-23
Classification: G01N,G01V

Abstract:
1. A method for subsurface exploration, comprising: receiving seismic data that were acquired by one or more seismic sensors; receiving a gamma value at a subsurface interface, wherein the gamma value is a ratio of Vp/Vs at the subsurface interface, wherein Vp is the average P wave velocity and Vs is the average S wave velocity; receiving a converted wave reflection coefficient at the subsurface interface, wherein the converted wave reflection coefficient is a function of a density contrast at the subsurface interface and a shear velocity contrast at the subsurface interface, and the converted wave reflection coefficient is determined from the seismic data; determining a P wave incident angle such that the converted wave reflection coefficient is a function of substantially only the density contrast at the P wave incident angle, wherein the P wave incident angle is referred to herein as θ; and calculating the density contrast based on the converted wave reflection coefficient at θ.