The reflection coefficients calculated using Zoeppritz equations plotted against angle of incidence show exactly what we expected. The highest layers of the well show a typical Class III interface. This is what we would expect to find when a low impedance saturated sand layer is directly beneath a high impedance shale layer. The gas saturated shale is shown by a dashed line and the brine sand is plotted with a solid line. One can see that the AVO response of the shale over gas saturated sand increases dramatically with angle in the shallow sections of the well. The central portion of the well (approximately 2.4 km below the surface) exhibit typical Class II behavior found in areas of little impedance contrast between the shale and adjacent sand layers. Again, the brine values are plotted with a solid line and the gas saturated sands is represented with a dashed line. Finally, one can see that the deepest sections of the well behave as Class I wells should behave. The high impedance sand cause an increasing negative amplitude with angle. It is also interesting that the effect of the gas on reflection coefficient is less in the deep section of the well, due to the effect of the overburden pressure.