SNR Gas Field is located in the north-eastern coastal region of Senoro-Toili Block on the eastern arm of Sulawesi Island. Six wells have been drilled since 1999. All wells proved significant gas column in Mentawa and Minahaki limestone. Well tests indicate gas rates in the range of 18 – 20 MMSCFD from selected intervals in both formations. An integrated geological-geophysical and reservoir study has been conducted to assist in formulating development plan scenarios for SNR Field. The key factor which leads to better understanding of the potential areas is an integrated 3D reservoir model, including a detailed petrophysical analysis. This paper focuses on the process of building a 3D static reservoir model. A reservoir modeling study was begun using 2D seismic interpretation and well correlation to build the structure model. Petrophysical analysis was performed using well-log & core data. At the cored well, lithology and reservoir properties were carried out to determine the rock types of Minahaki-Mentawa Formations. These were divided into 3 groups (i.e. good, medium and poor), while rock types in un-cored well were interpreted from logs. Acoustic Impedance (AI) model is the first property model that was created, based on AI well-log and AI map from each horizon. In rock type modeling, AI model was used as a secondary variable. Cross-plot analysis between porosity versus AI showed a good relationship, therefore AI model was used also as a secondary variable in porosity distribution, based on Sequential Gaussian Simulation method. A permeability model was made using a property calculator and porosity permeability transform formula, while a water saturation model was calculated based on capillary-gravity equilibrium formula. Volumetric calculation shows quite a large amount of gas accumulation. Based on the reservoir simulation results, sixteen well locations for development drilling have been proposed, which will lead to the optimal development of this field.
Author : Dian Kurniawan, Ferry Faris Baskaraputra, Sugiyanto, Anies Baasir, Dwi Hudya Febrianto