Traveltime parameters in a tilted elliptical anisotropic medium‡.

ABSTRACT In this paper, we derive analytical expressions for one-way and two-way kinematical parameters in elliptical tilted transverse isotropy media. We show that the homogeneous elliptical tilted transverse isotropy models result in hyperbolic moveout with a reflection point sideslip x₀, which can be considered as an additional traveltime parameter for one-way wave propagation. For homogeneous elliptical tilted transverse isotropy models we show that the inversion of one-way traveltime parameters suffers from the ambiguity for large tilts. It is shown that the accuracy of the inversion is sensitive to the error in x₀. We also derive and invert the traveltime parameters for a vertically heterogeneous elliptical tilted transverse isotropy model with a tilt gradually changing with depth. The a priori knowledge of parameter δ is very important for inversion. The wrong choise of this parameter results in significant errors in inverted model parameters. [ABSTRACT FROM AUTHOR]