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| | Abstract | | In order to use the waveform inversion for the oil/gas reservoir structure study, it might be better to use seismic waves lower than 10 Hz. To study the propagation of low-frequency seismic waves for the waveform inversion, we carried out the experiment using the low-frequency seismic ACROSS source in Mori town, Shizuoka Pref., owned by JMA and 11 2Hz 3C-geophones along the survey line of 3 km long. The source was operated between 3.5-7.5Hz. Although the observed period is only 4 days, we obtained high S/N ratio at 3 km offset using 4 hours data. We interpreted data using assumed structures. The significant reflected arrivals are difficult to detect due to short offset distance, frequency and mode of seismic waves. If we use low frequency seismic waves such as 3.5-7.5 Hz, we can detect subtle changes in underground caused changes of oil/gas reservoir characteristics by 4 hours data. |
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