First-order lateral interval velocity estimates without picking

Antoine Guitton, Jon Claerbout, and Jesse Lomask

antoine@sep.stanford.edu, jon@sep.stanford.edu, lomask@sep.stanford.edu

ABSTRACT

A new method for estimating interval velocities without picking is proposed. The first step applies a normal move-out correction with a v(z) stacking velocity to common mid-point gathers. The second step estimates local stepouts at every offset and time for each gather. Local stepouts across offset are then integrated to obtain local time shifts. The integration is done in the Fourier domain for increased speed. Finally the interval velocity is estimated in the $\tau$ space by fitting the time shifts with a tomographic inversion procedure based on a straight rays geometry. This approach is tested on a Gulf of Mexico dataset with flat geology where recovery of lateral velocity variations across faults is demonstrated.