SEGJ Technical Conference

Time Lapse experiment using the seismic ACROSS source near the Nojima-fault in Awaji Island-Generation of vertical and horizontal vibration by synthetic method

Abstract In order to watch the temporal change of oil/gas/CO2 reservoirs, it is important to develop accurate 4D (time-lapse) method. For these objectives, we use ultra-stable seismic source called ACROSS and multi-geophones. Using newly developed seismic ACROSS source, we examined the waveforms of observed 32-three component geophones exited by the source in Awaji Island. The seismic ACROSS can generate seismic signals from 10 to 50Hz with 40 ton-f at 50Hz. By the addition and the subtraction of clockwise and anti-clockwise rotations of the eccentric mass of the ACROSS, we obtained transfer functions between a source and a receiver for vertical force and horizontal force. It is found that addition and subtraction process of clockwise and anti-clockwise rotation records can satisfactory generate P and S wavers, respectively.