Using AVA Geostatistical Inversion for Thin Layer Reservoir Characterization - A Carbonate Reservoir Case Study

Seismic inversion plays an important role in reservoir characterization. Simultaneous inversion of pre-stack seismic data produces elastic properties that can be related to reservoir properties such as porosity and water saturation. In this study well logs and pre-stack time migrated seismic data were used to characterize thin carbonate reservoir layers of Arab Formation in an oil field located in Persian Gulf. First, a deterministic simultaneous inversion was conducted, but these thin layers were not distinguishable in the results. Therefore, Geostatistical inversion was used to achieve higher vertical resolution. Afterwards, the water saturation and porosity of reservoir layers were estimated by cosimulation of geostatistically inverted P impedance and Vp/Vs. Finally, uncertainty of results was quantified and high reservoir quality bodies were captured. Simultaneous geostatistical inversion of pre-stack seismic data leads to delineation of thin layers of Arab formation. In addition, this inversion method provides possibility of reservoir properties estimation and reservoir geo-bodies extraction in this oil field.