Velocities from amplitude variations with offset

摘要

The sensitivity of amplitude variations with offset (AVO) to normal-moveout (NMO) velocity errors has usually been taken to be a significant limitation of the method. However, this sensitivity can, in most cases, be exploited to obtain more accurate velocities from a fully automated procedure. The error due to velocity in the AVO gradient is in phase quadrature with the AVO zero- Offset intercept. Furthermore, if the majority of reflectors Within a suitable data window contain a similar gradient Quadrature component, then it may be inferred that this Component is due to an NMO velocity error.