A method of monitoring heavy oil recovery in a hydrocarbon reservoir including the steps of obtaining a set of acoustic signals; deriving from the obtained signals a velocity model including shear and compressional velocities for at least a section of the reservoir; defining a relation relating shear and compressional velocities to at least one material parameter of the heavy oil; performing a reservoir treatment process; obtaining an in-situ or post-treatment set of acoustic signals; and deriving from the in-situ or post-treatment set of acoustic signals shear and compressional velocities and the at least one material parameter using the relation.