Seismic reservoir characterization of a deep water sandstone reservoir using hydraulic and electrical flow units: A case study from the Shah Deniz gas field, the South Caspian Sea

Seismic reservoir characterization of deep water sandstones using hydraulic and electrical flow units plays an important role in delineation of oil and gas traps in the Caspian Sea basin. The proposed methodology of this study comprises two major steps. Firstly, the reservoir rock types, including Hydraulic Flow Units (HFUs) and Electrical Flow Units (EFUs) are estimated from petrophysical data. Secondly, seismic data are converted into HFUs and EFUs by using the seismic attributes technology in conjunction with the neural networks and fuzzy clustering algorithms. Optimal seismic attributes for the estimation of Current Zone Index (CZI) and Flow Zone Indicator (FZI) include acoustic impedance, which was derived from a model based inversion, together with dominant frequency and amplitude envelope data. High porosity and permeability zones are delineated by using the seismic derived flow zone indicator data. Since there is a strong correlation between water saturation and current zone indicator, hydrocarbon saturation changes within the sandstone packages are investigated by using the EFU model. The integrated approach introduced in this study is successful in highlighting high porosity and low water saturations zones of the Shah Deniz sandstone packages.