f Robust P-wave attenuation estimates from VSP first arrivals

Compressional wave attenuation is correlated with the porosity, clay content and permeabilty of rocks (Klimentos and McCann 1990), pence attenuation potentially offers a method of remotely sensing these parameters. The vertical seismic profile (VSP) offers an ideal acquisition geometry for the measurement of compressional wave attenuation by determination of the log spectral ratio (LSR) beween succesive geophones. Due to the low frequency (peak at 20Hz) and narrow bandwidth (15Hz-60Hz) of the typical VSP source and also due to the effects of interference and transmission losses, great care must be taken if reliable attenuation estimates from real data are to be obtained.