Chapter 1: Introduction
In this book, we present a unified theory of 3D seismic true-amplitude imaging that can be applied to seismic records under general measurement configurations. The precise formulation of the true-amplitude concept, which depends on the specific imaging task under consideration, will be given below.
The theory relies on the ray-theoretical description of the seismic wave propagation involved and assumes an a priori macrovelocity model. This is an initial, or reference, velocity model that incorporates the basic information we have from the subsurface to be imaged.
The imaging theory consists of a weighted true-amplitude diffraction stack to migrate the seismic-reflection data from the time-trace domain into the depth domain, and a weighted true-amplitude isochron stack to demigrate the migrated seismic image from the depth domain back into the time-trace domain. The diffraction and isochron stacks are explained in connection with true-amplitude migration and demigration. The stacking operations can be cascaded, or chained, for different measurement configurations, velocity models, or elementary waves to permit a variety of true-amplitude image transformations.
Many of the described ideas and results are contained in research articles that we have published over the last few years. Our goal is to provide an updated, didactic tutorial of the subject that is accessible to a broader audience that wishes to understand it and, above all, use it.