RESERVOIR CHARACTERIZATION AND PETROLEUM SYSTEM ANALYSIS WITH ACOUSTIC IMPEDANCE, SEISMIC ATTRIBUTES, AND SPECTRAL DECOMPOSITION METODHS IN PROSPECT GANDARIA - NORTH SUMATRA BASIN

• Main Author: Pitas Malay, Raisa
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/80455
• Institution: Institut Teknologi Bandung

The North Sumatra Basin is a hydrocarbon-producing sedimentary basin that is being explored in Indonesia. This research is focused on one of the locations in the basin, the Gandaria Prospect with the research well named GDA-009. In the research area, reservoir distribution is usually carried out by lithological correlation between wells. But with 3D seismic data, it may give us more detail about well information. This research aims to characterize the reservoir and identify the distribution of lithology that have potential as reservoirs and analyze the petroleum system. The data used is well log data and 3D post stack time migration (PSTM) seismic data. The closest reference well to the research area is GDA-003 with 4 km. The analysis focused on the Belumai Formation using several methods, such as seismic attributes, spectral decomposition, and model-based seismic inversion. Seismic attributes used include RMS amplitude, instantaneous frequency and sweetness which help in mapping the lateral distribution of reservoir layers. Amplitude variance attribute is used to view trap stratigraphy. Spectral decomposition is used to see the distribution of lithology and validate the sealing petroleum system from variance amplitude. Based on the results of the analysis of several methods, the RMS amplitude and instantaneous frequency attributes succeeded in identifying the continuity of the lateral distribution of the target lithology in Belumai sandstone formation. The sweetness attribute shows that there is a sweet spot which indicates hydrocarbon accumulation. The spectral decomposition attribute is able to identify the continuity and distribution of sandstone reservoirs. The variance attribute can be identified in the image visible around the prospect well GDA-009 which can be identified as shale as sealing (stratigraphic trap). Model-based acoustic impedance inversion provides physical characteristics for reservoir distribution.