Formation anisotropic constants from sonic data acquired while drilling

Formation anisotropic constants play an important role in the determination of formation stresses, fractures, lithology, and mechanical properties. These characteristics provide critical inputs to wellbore stability during drilling optimal completion designs hydrocarbon bearing reservoirs. However, there are no available techniques for estimation a sub-set using Logging-While-Drilling (LWD) sonic data. Inversion LWD-sonic data is rather challenging because strong coupling between collar-flexural formation-flexural modes propagating along borehole. The influence collar flexural on significantly different fast slow formations. Consequently, frequency dependent sensitivities measured dispersions changes as well. New inversion algorithms estimates Transversely-Isotropic (TI)-constants from both Computational results confirm validity proposed synthetic dispersion obtained Bakken shale Austin chalk TI-formations presence drill-collar account LWD tool liquid-filled