On the theory of acoustic sounding of near-borehole zones of porous and permeable rocks
© V.Sh. Shagapov, Z.A. Bulatova
The possibility of sounding the near-borehole zones of porous and permeable rocks using acoustic waves of pressure and fluid situated in the borehole is analyzed. For this purpose the paper presents results of the studies of the evolution of acoustic waves in cylindrical channels having permeable sites surrounded by porous space. The quantitative and qualitative features of the wave dynamics depending on the state of the inhomogeneous porous medium, in particular when the channel is surrounded by cracks or a weakly permeable "crust", are shown. Besides, processes of acoustic signal propagation in a circular slit whose one wall is a permeable rock and the other one is impermeable (the probe case) have been studied. The results showing that the collector characteristics of rocks can in some cases notably influence the acoustic signal evolution in the channels have been obtained. This, in turn, sets hope for the use of the acoustic method considered to check the near-borehole zones.