Gassmann’s Equation and Frequency Dependent Elastic Response - an Experimental Study

B-40 GASSMANN’S EQUATION AND FREQUENCY DEPENDENT ELASTIC RESPONSE – AN EXPERIMENTAL STUDY Abstract 1 The frequency dependent response of an artificial rock sample was measured in the frequency range between 3 Hz and 500 kHz and compared to the Gassmann prediction which is the low frequency limit of the fluid response. The low frequency response shows a good agreement with the prediction while the ultrasonic measurements especially at partial saturations show a large difference and can better be described with a theory like patchy saturation. Introduction Gassmann (1951) used linear elasticity to calculate the effect of fluids in a porous