CARBONATE RESERVOIR CHARACTERIZATION OF THE MENTAWA FORMATION IN THE

• Main Author: Kautaman Andhika Putra, Dimas
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/87889
• Institution: Institut Teknologi Bandung

The "Pandawa" field is a hydrocarbon field located in the Banggai-Sula Basin. This study focuses on the Mentawa Formation, a carbonate build-up formation situated above the carbonate platform of the Minahaki Formation. The geological complexity, with significant lateral and vertical variations, presents a challenge in reservoir characterization in this field. Therefore, a method capable of accurately characterizing the reservoir is needed. Analysis of various elastic parameters from well data indicates that AI and the Vp/Vs ratio are sensitive elastic parameters. The Linear Programming Sparse Spike (LPSS) inversion method is used to address the bandwidth limitations of the seismic data. The results effectively demonstrate the lateral distribution of porosity and fluid presence, indicated by low AI values and a low Vp/Vs ratio. However, the elastic parameter inversion results tend to be biased and show linear relationships, whereas petrophysical parameters such as porosity and fluid saturation have non-linear relationships. Therefore, an inversion approach using Curved Pseudo Elastic Impedance (CPEI) and Pseudo Elastic Impedance Lithology (PEIL) attributes is employed to better approximate the nonlinear trends of petrophysical parameters related to fluid trends and compaction trends. The CPEI and PEIL attributes are formulated using a trigonometric approach to petrophysical parameters: resistivity and water saturation to represent fluid trends, and density and porosity to represent compaction trends. The results show that CPEI correlates well with resistivity and water saturation, while PEIL correlates well with density and porosity. These CPEI and PEIL attributes are then transformed into pseudo resistivity, water saturation, density, and porosity volumes, providing a more accurate representation of the reservoir conditions. The results indicate that the reservoir in the Mentawa Formation at the Pandawa field has high porosity and low water saturation, filled with hydrocarbon fluids.