3D Seismic Reservoir Characterization and Delineation in Carbonate Reservoir

Abstract

West Betara (WB) Field is located in South Sumatra Basin, Indonesia, tested hydrocarbon (Gas) from carbonate reservoirs of the Batu Raja Formation. This is an interesting challenge to describe the lateral distribution and its property within carbonate reservoir at minimum data information. The objectives of this study are to delineate carbonate reservoir distribution including the laterally rock properties by using seismic reservoir characterization methods. The availability of 3D seismic data, DST’s data, conventional well data as wireline and mudlog data is very helpful in answering the challenge. By optimizing well data information, the sensitivity analysis can be generated from wireline log data to determine gas zone and appropriate seismic reservoir characterization method. 3D Seismic data provides helpful inter-well information for determining and visualizing reservoir structure and rock properties at the present day, they help us to generate seismic inversion model and multi-attribute analyses to predict reservoir boundary and its property distribution laterally. The sensitivity analysis of cross-plots combination from Gamma Ray Log, Acoustic Impedance (AI) Log derived from Sonic and density log, Neutron-Porosity Log and Resistivity Log shows good separation for gas zone in carbonate reservoir. The results help us to predict reservoir boundary and its property distribution laterally by seismic inversion and multi-attribute method in our 3D seismic data. The Gamma ray (low value) and AI (high value) maps are showing consistency of carbonate reservoir delineation. In line with Gamma ray and AI maps, the porosity map of the carbonate reservoir shows gas zone (high value) with certain pattern and it is consistent with tested well data. The result of the study has been successfully delineating carbonate reservoir distribution including the property laterally within West Betara Field.