LEAKY MODES AND WAVE COMPONENTS OF A FLUID-FILLED BOREHOLE EMBEDDED IN AN ELASTIC MEDIUM

Based on the analysis of the complex poles of the characteristic funct ion of the borehole system on four major Riemann sheets corresponding to the leaky modes, the wave components, such as compressional head ar rival, shear wave and Stoneley wave, are calculated. It is pointed out that the existing head wave theory which neglects the contribution of the leaky modes is not applicable to the wave component calculation o f the formation of large Poisson ratio. An improved method is proposed to isolate and calculate the wave components effectively and accurate ly.