f Cased borehole effects on downhole seismic measurements

Interactions of seismic wave with an open borehole is well studied, especially in the low frequency limits (White, 1953 ; Schoenberg, 1986; Lovell and Hornby, 1990 ; Peng et al., 1992). Less understood is the distortion of incident wave by presence of radially layered casing and cement around a borehole. This paper is devoted to the cased borehole effect on downhole seismic experiment, which is an extension of our works reported last year at the Paris EAEG meeting.