in seismic data processing there is a step of calculating the absorption represented By Q value which is Q factor , how we can estimate it from VSP ! thank you.
The simplest method is the spectral ratio method where the frequency spectra at two different depth levels in the VSP are computed and divided i.e. the ratio of the spectra. IN theory the slope of this spectral ratio is related to the attenaution factor Q. However, this method is not very robust and the data needs careful preconditioning to remove reflections, multiples, conversions etc. There are many others methods that have been developed and are described in the literature e.g. Geophysics.