Gravity and Passive Seismic Application in Exploration and Development Bunyu Field, Indonesia

Bunyu Field is mature field in Tarakan Basin was discovered in 1901 and has been developed since 1950. The main problem is to delineate hydrocarbon accumulation in combination structural-stratigraphic trap. The existing seismic data is poor quality due to highly attenuated weathering layer, shallow coal layer and topography. Vertical gradient gravity and low frequency passive seismic is applied to delineate structure and hydrocarbon distribution within reservoir.Second vertical derivative of Bouguer anomaly assist in interpreting the structure, vertical gradient anomaly is used to detect low low density anomaly distribution and low frequency passive seismic amplitude spectrum used as hydrocarbon indicator. The result have good consistency with current production wells and discovered 2 anomalies which could be followed up with drilling new wells