title: Tube-wave propagation in a fluid-filled borehole generated by a single point force applied to the surrounding formation.
abstract: Propagation of tube waves in an infinite fluid-filled borehole, generated by a single-force point source placed in the elastic surrounding formation, is analyzed in the long-wave approximation. Integral representations of the precise solution are obtained both for fast and slow formations. An asymptotic analysis of tube-wave propagation in the fluid-filled borehole is performed on the basis of these two integral representations. The complete asymptotic wave field in the borehole fluid for a fast formation consists of P and SV phases and the lowest eigenmode of the Stoneley wave (tube wave). For a slow formation the conical Stoneley wave (Mach wave) is generated. It appears only behind the critical angle defined by the ratio of the S wave velocity in the formation to the low-frequency Stoneley wave velocity and decays weakly with an offset. Asymptotic wave forms are in good agreement with wave forms obtained by straightforward calculations.
authors.affiliation: Department of Modeling of Physical Processes in Environment, Moscow State Engineering Physics Institute (State University), 31 Kashirskoe Shosse, 115409 Moscow, Russia.
authors.forename: Pavel M
authors.initials: PM
authors.lastname: Bokov
authors.forename: Andrei M
authors.initials: AM
authors.lastname: Ionov