Interval velocity estimation using iterative prestack depth migration in the constant angle domain

This article discusses a technique which a number of people at Amoco have been working on since the early 1980s. We begin by answering two questions: What is the constant angle domain? and Why would anyone want to use it? First, although the concept has been around for the better part of two decades, the term (constant angle) is not widely known (for example, it is not included in SEG's Encyclopedic Dictionary of Exploration Geophysics) probably because seismic exploration has traditionally used a point source which generates rays in all directions. The constant angle technique, on the other hand, uses an extended source which produces a plane wave that has a single ray parameter along its entire length.