Ultrasound propagation in porous rocks: Theory identifies three distinct wave modes‎

Ultrasound-based irradiation of rock formations has attracted considerable attention as a technique for enhancing heavy-oil (high-viscosity crude oil) recovery from deep underground reservoirs. However, a unified theoretical framework for wave propagation and energy dissipation in these formations remains lacking because water coexists with heavy oil within rock pores, and gas bubbles in the water respond dynamically to ultrasonic excitation, thereby creating a complex system.