Stochastic Inversion and Low-Frequency Passive Seismic Integration for Sand Distribution Opportunities in BTG Field, South Sumatra

Deterministic seismic inversion has been widely successful in various exploration and development projects but exhibits limitations in effectively resolving thin layers due to its tendency to produce smooth and blocky results. To address this, geostatistical inversion has been applied to enhance the resolution of thin layers that deterministic seismic inversion struggles with. Additionally, low-frequency passive seismic (LFPS) methods have been utilized to optimize hydrocarbon drainage. LFPS continuously records signals or background noise originating from both surface and subsurface activities. These methods have been applied to the Betung Structure in the South Sumatra Basin, a gas and oil-producing structure from limestone and sandstone reservoirs of the Talangakar Formation. The study aimed to determine the presence of hydrocarbons in the sandstone reservoir using an integration of stochastic seismic inversion techniques and low-frequency models from passive seismic data. The geostatistical inversion yielded high-resolution results for the sand-T layer at 12 meters and sand-S at 23 meters. The LFPS method also indicated hydrocarbon potential at the 2–4 Hz frequency, with LFPS amplitude and energy distributions showing a high correlation with existing production wells.