Abstract:Rock consists of pores and matrix particles. Theory of full-wave logging in porous formations reveals better the propagation characteristic of acoustic wave in borehole and formations. Revised Biot's wave theory is used to calculate synthetic waveforms of full-wave logging, to analyse low permeability, porosity, shale con tent and Poisson's ratio contribute to waveform respectively, and to describe how slow wave is influenced by permeability and porosity. This article expounds that permeability should be determined by taking Stoneley wave when the center frequency of acoustic source is quite low(&le5 kHz), or by adopting Airy phase of pseudo Rayleigh wave when the center frequency is high (The influences of porosity and shale content, etc. must be removed). Then tact porosity and shale content can be determined with the base of travel-time difference between P-wave and S-wave. FinaIIy that Poisson's ratio can be derived from late arrivals of P-wave.