Publications

Low frequency passive seismic, also known as micro-tremor, is employed by a growing number of oil and gas companies in Abu Dhabi, Dubai, Brazil, Russia, Saudi Arabia, Mexico, Austria, Norway, and a number of other countries to reduce exploration risks in hydrocarbon prospecting. Passive seismic can detect the existence of hydrocarbons by analyzing low frequency signals in the range of 1- 4Hz. In contrast to conventional 2D and 3D seismic technologies, passive seismic does not require artificial seismic excitation sources, such as explosives or vibrators. Despite the promise of this technology, passive seismic has not yet been deemed a ",valid", exploration tool in Indonesia, because it has a limited track record. Therefore it has not been employed widely in Indonesia.In 2010, a passive seismic survey was conducted in the onshore area of the Brantas Block, East Java, with 100 observation points. The points were located at existing wells, both over producing gas field and dry wells, and also over some prospects. The survey revealed a high correlation between passive seismic spectral properties, hydrocarbon presence and reservoir thickness. Advanced analysis showed that passive seismic can be used to infer the boundaries of hydrocarbon deposits.The conclusion of this study was that passive seismic is a valid tool for prospect ranking and reducing uncertainty in drilling.Keyword: Passive Seismic, low frequency, spectral, anomaly, oscillations, resonance.