Reservoir Characterization and Volumetric Calculation of Hydrocarbons Reserves in “RRD” Field, Layer Z.2260 Talang Akar Fomation, North West Java Basin

Abstract

“RRD” field is one of the hydrocarbon prospects in North West Java Basin. One of the potential oil reserves in this field was found on Talang Akar Formation Z.2260 layer and indicated by the presence of oil show on drill steam test data. Physical parameters such as acoustic impedance, porosity and hydrocarbon saturation are essential to determine the distribution of reservoir layer. Acoustic impedance can distinguish the reservoir and non-reservoir zone, while porosity and hydrocarbon saturation can be used in the calculation of oil reserves on the layer Z.2260. Model Based Inversion was performed to find out the lithology distribution determined by acoustic impedance. Porosity distribution was identified using crosspiot acoustic impedance and porosity analysis while hydrocarbon saturation distribution was determined using cokriging geostatistical analysis. The result shows the existence of sandstone reservoir with acoustic impedance values ranging from 8500-10.000 (m/s)(g/cc) that spreads over 2 zones in the research area of anticline zone A and R. Sandstone with such acoustic impedance range has a porosity value of 8-12% and hydrocarbon saturation 25-50%. The reservoir zone A has value 0,201 (MMbbl) as well as R area 1,689 (MMbbl).