Downhole Orbital Vibrator as Source for 1km-Offset Crosswell Seismic Wave-Guide Surveys

P224 DOWNHOLE ORBITAL VIBRATOR AS SOURCE FOR 1KM- OFFSET CROSSWELL SEISMIC WAVE-GUIDE SURVEYS 1 L. WALTER 1 and P. LEARY 1 1 Geospace Engineering Resources International 12750 S. Kirkwood Stafford Texas 77477 USA The downhole orbital vibrator (DOV) provides a stable acoustically-coupled linear-physics swept-frequency far-field seismic wavelet with frequencies in 50-350Hz band and a cylindrically-symmetric angular power-band at angles < 20 o -30 o from the plane normal to the host borehole. Tube wave generation is negligible. DOV-excited acoustic waves have a uniform displacement amplitude � 1-3� across the DOV axial cross-section. Because the acoustic wave motion is spatially limited