Determining the oil-gas contact using Amplitude Versus Offset (AVO) technique in a sandstone reservoir of the southern Iran

Reservoir geophysics studies have playeda significant role in exploration and production activities during the last decades. These techniques often try to identify the lithology and fluid content of the reservoir by utilization of pre-stack seismic data. The most effective type of these studies is performed in sandstone reservoirs,in which shear sonic logs increase the quality of the results. In this study, Amplitude Versus Offset (AVO) technique is applied in one of the sandstone reservoirs in the Persian Gulf. The applied methodology is based on modeling of seismic responses with different scenarios of fluid saturations in order to identify,using rock physics models, theseismic behavior of the reservoir in wells lacking shear logs. To achieve this goal, petrophysical interpretations of well data and reservoir parameters were integrated into a rock physics model, which eventually helped to recognize the seismic attributes sensitive to fluid content of the reservoir. In addition, calculation of pre-stack seismic attributes data led us to discriminate accurately the gas-oil contact. The comparison of the AVO study results with petrophysical evaluation results shows that AVO method results are very reliable and precise in the study area.