ASSESSMENT OF A POTENTIAL HYDROCARBON RESERVOIR IN A YOGYAKARTA BASIN USING BROADBAND-NOISE ANALYSIS

The search for hydrocarbon reservoirs through geophysical exploration in a particular basin has been in common recently. In this study, a potential hydrocarbon reservoir situated in a Yogyakarta Basin in Central Java, Indonesia was assessed using broadband-noise spectral analysis of spectrograms recorded by 2 local seismic stations: UGM and YOGI, where the broadband data included 3 components of waveforms. The aims of this study are thus twofold; firstly, we report the characteristics of micro-tremor seismic signals generated by a hydrocarbon reservoir in the region of interest and then secondly, we examine these findings in the context of determining which seismic station is likely to be positioned above the potential reserve for hydrocarbons and estimating the depth of a hydrocarbon reservoir. The results of broadband-noise seismic experiments revealed that the peak of micro-tremor anomalies associated with a hydrocarbon reserve was only detected by YOGI station. This primary finding suggests that, instead of UGM station, the YOGI station is arguably lying above a potential hydrocarbon reservoir with the layer depth is estimated to be 12-35 m. Discussions on these results include the practical use of broadband-noise experiments with a low pass-filtered frequency in geotechnical and industrial applications.