The effects of stress concentrations of cased hole on induced azimuthal anisotropy velocity distribution
套管井应力集中诱导井周波速各向异性的研究

According to the need of estimating anisotropy and abnormal stress of formation by cross-dipole logging in a cased hole, we show how stress concentrations affect the velocity distribution of formation around a cased hole, and how the velocity distribution influences the cross-dipole anisotropy measurements by computing the stress distribution of a cased hole subjected to the tectonic stress and applying acoustoelasticity theory. The introduction of casing and cement in a cased hole results in that the range of stress concentrations becomes small. The crossover of shear-waves of radial polarization moves towards the borehole. The azimuthal extremum of shear-waves is changed. But the azimuth of compressional velocity minima can still provide an excellent indicator of the direction of maximum far-field tectonic stress.