Estimation of Gas Saturation by Frequency-dependent Amplitude-versus-offset Analysis

We present a new method for the determination of gas saturation from frequency-dependent amplitude-versus-offset analysis. The method works by combining measurements of attenuation with a “low-frequency” acoustic impedance to resolve gas saturation variations. The concept is validated on synthetic data before being applied to field data from a producing gas reservoir. We present both the pre-drill and post-drill analyses, and conclude that the method shows great potential for improving our ability to estimate rock and fluid properties from seismic data.