Patent ID: 8913460
Filing Date: 2014-12-16
Classification: G01V

Abstract:
1. A method comprising: providing, in a borehole, a transmitter and a series of receivers spaced linearly from the transmitter at known different distances from the transmitter; measuring linear propagation times for a signal to propagate linearly from the transmitter to each of the receivers; determining an inline velocity based at least in part on the linear propagation times; measuring reflection times for a signal to propagate from the transmitter to a boundary and from the boundary to each of the receivers; for each of the reflection times, providing a time-distance anisotropic velocity (TDAV) relationship that depends on an effective signal velocity in an anisotropic subterranean formation adjacent the boundary as a function of reflection angle for the reflection time signal with respect to the boundary, inline velocity and orthogonal velocity, orthogonal to the inline velocity; performing semblance processing to combine the time-distance anisotropic velocity (TDAV) relationships with the inline velocity to provide for a best-fit calculation of the effective signal velocities for the different reflection angles of the reflection time signals; and based on the best-fit calculation, calculating for each of the effective anisotropic velocities a distance for the corresponding receiver to the boundary.