RESERVOIR CHARACTERIZATION FOR CONGLOMERATE SANDSTONE, LOWER TANJUNG FORMATION, IN “BUNGA” FIELD, BARITO BASIN

• Main Author: Fitria Rahmawati, Febriani
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/42296
• Institution: Institut Teknologi Bandung

“Bunga” field, located in Barito Basin, is a productive reservoir field in Indonesia. Lower Tanjung formation which is the main focus of this research is the main production layers. In order to leverage the hydrocarbon production, a better study of reservoir characterization has to be done for searching the upside potential. Lower Tanjung formation consists of sandstone, conglomerate and shale. The challenge of this research were no check shot was provided hence no time-depth relations and the presence of conglomerate made sensitivity analysis was tough. Using Gamma Ray cutoff 95 API, 52% certainty of sand was obtained. In the presence of sandstone, Vp and Vs has lower velocity and higher Vp/Vs ratio. Therefore the application of seismic model based inversion using Amplitude Variation with Offset Two-Term (AVO 2T) analysis to extract reflectivity-P volume and reflectivity-S volume was proposed. Aside from that, this research performed Extended Elastic Impedance (EEI) to get Vp/Vs ratio reflectivity volume with chi angle -45o. These three volumes were inverted by using model based seismic inversion. To improve the resolution Filter Wiener Optimum (FWO) was applied. FWO has been proven to improve the quality of seismic inversion. For interpretation relative impedances were used. Better separation between target and non-target area was observed and relative impedance minimized the effect of low frequency model. Negative values of relative P-Impedance and SImpedance were indicating the presence of porous lithology and positive values of relative Vp/Vs indicating the presence of fluid. Potential good reservoir area are located in the east of Tulip- 105 and the west of Tulip-107.