Gas saturation calculated from patchy and homogeneous models at foinaven field

There are several methods by which partial gas saturation can be predicted from acoustic impedance results. Here well logs and core are used along with Gassmann Equations, Voigt and Reuss averages for the fluid mixture (corresponding to patchy and homogeneous mixtures respectively) to predict gas saturation changes at the Foinaven Field. Differences between using Voigt and Reuss averages can be minor depending on the end points assumed for the Voigt average. If low saturations of moveable gas are present, then these differences can be much larger and result in substantial uncertainty in gas saturation. Here, the calculated change in acoustic impedance is used to predict gas saturation increase at the Foinaven Field, based on time-lapse seismic surveys.