APPLICATION OF SEISMIC ATTRIBUTE AND 2D ACOUSTIC IMPEDANCE INVERSION TO MAP THE DISTRIBUTION OF GAS RESERVOIR AT BATU RAJA FORMATION STRATIGRAPHIC TRAP IN 'TERRA' FIELD, SOUTH SUMATERA BASIN

• Main Author: Muzakki Puar, Anugrah
• Format: Final Project
• Language: Indonesia
• Subjects: Teknik (Rekayasa, enjinering dan kegiatan berkaitan)
• Online Access: https://digilib.itb.ac.id/gdl/view/36864
• Institution: Institut Teknologi Bandung

Oil and gas production in Indonesia has declined in recent years, so research in several areas that has not yielded optimal results, needs to be done. One of the basin that still needs to be examined is South Sumatra Basin, with carbonate reservoirs in the Batu Raja Formation as the target. This research field is located in the west area of the South Sumatra Basin. After analyzed total gas value in mudlog and the well logging response, the carbonate reservoir of the Batu Raja Formation shows the potential of hydrocarbons with the stratigraphic trap. The purpose of this study is to determine the distribution of carbonate reservoir as the consideration for well development location. In this study, seismic data available in this area were 2D seismic data from seven vintage. Consequently, amplitude response of seismic varies and the continuity of the layers is not clear which complicates the process of structural and stratigraphic interpretation. To overcome this problem, the cosine of phase attribute is applied when picking the horizon. Then, based on sensitivity analysis by crossploting the log data, acoustic impedance (AI) crossplots with neutron porosity can separate carbonate zone with other lithologies and can be able to indicate the presence of hydrocarbons. Therefore, an effective method for achieving the objectives of this study is AI inversion. The result of these inversions will be sliced to obtain AI distribution laterally. The AI distribution map was then transformed into neutron porosity distribution map by using linear regression. As the results, it can be concluded there are two prospect area that have characteristic of low AI value and high neutron porosity. First, it’s located in the northwestern part of the study area, precisely at the northeast part of well KEN-AMP-1. It's estimated because this high area is dissoluted. Second location is near well SUL-AMP-1 because there are fractures due to tectonic processes.