IDENTIFICATION OF LAMPUNG SEDIMENTARY BASIN (SE SUMATRA) USING GRAVITY FORWARD MODELING AND SEISMIC INTERPRETATION

This study investigates the configuration of sedimentary basin in Lampung area, the southeastern part of the Sumatra Island, using integrated gravity and seismic data. This research aims to enhance the understanding of sedimentary basin structures, focusing on the identification and delineation of sub-basins, basement highs, and fault systems. Gravity data analysis, including Bouguer anomaly mapping and spectral analysis, was used to estimate the depth of sedimentary layers and the configuration of the basement. Seismic data provided direct observations of subsurface reflectors, aiding in the identification of fault structures and stratigraphic continuity. The integration of both datasets allowed for the creation of a detailed geological model of the basin, supported by well log data from wells LPG-1, LPG-2, and LPG-3. The study identified seven major sedimentary sub-basins, among which are Negara Batin, Menggala, East Menggala, Terbanggi, Metro, and Kotabumi. Forward modeling results indicate that the Terbanggi sub-basin is the deepest, with a maximum depth of approximately 3 kilometers. The presence of volcanic material, particularly tuffaceous sandstone and tuff breccia in the Lower Lahat and Baturaja formations, was confirmed through well and seismic data, highlighting the interaction between volcanic and sedimentary processes in the basin’s evolution. This integrated approach provides a more accurate understanding of the basin’s geometry and structural features, offering valuable insights into the tectonic history of the region. The findings contribute to future geological studies and exploration efforts, demonstrating the effectiveness of com­bining gravity and seismic data in analyzing complex subsurface environments.