Modeling Squirt Dispersion and Attenuation of Ultrasonic in Fluid-Saturated Rocks at the Core Scale

Abstract

Abstract Modeling dispersion and attenuation of ultrasonic wave in fluid-saturated rocks at core scale, the effect of the local flow of the pore fluid induced by the passing wave can’t be neglected. The squirt-flow mechanism between pores of different shapes and orientations should be considered in the ultrasonic simulation of the pore structure. A core scale modeling method for velocity dispersion and attenuation of saturated carbonate at laboratory frequencies is developed based on the ultrasonic pulse transmission method, can be used to simulate the effect of the different pore structure on velocity dispersion and attenuation of core samples. The elastic moduli matrix of stress-strain function of rock contain stiff pores and compliant pores are described by the squirt flow model and the velocity dispersion and attenuation are calculated by waveform of two piezoelectric transducers. Then, the methods of obtaining the parameters in the model are introduced. For the validation, we consider several models consisting of different pore space embedded in an elastic solid grain material, it shows our model considering squirt-flow is in good agreement with the results of petrophysical experiments.