Dipole Flexural Waves Splitting Induced by Borehole Pressurization and Formation Stress Concentration

Abstract

AbstractWe numerically calculate the Stoneley and flexural mode dispersion curves in a fluid‐filled borehole with borehole pressurization and uniaxially stressed solid formation. From the computational results of sensitivity coefficients and velocity‐stress coefficients, we show that the sensitivity coefficient without the third‐order elastic constant is larger than the other sensitivity coefficients , but the velocity‐stress coefficient corresponding to it is less than the other velocity‐stress coefficients with the third‐order elastic constants. Therefore, the fractional changes in the phase velocity hardly relate to the sensitivity coefficient without the third‐order elastic constant. In addition, computational results show that the point of dispersion curve crossover is affected by the borehole pressurization because of the change of velocity dispersion by borehole pressurization increasing with frequency, and as the borehole pressurization increases the velocity of the crossover point increases while the frequency of the point is unchanged.