Introduction

Small velocity anomalies can create AVO effects by focusing the reflected seismic wavefield. This impedes AVO analysis. The AVO anomalies caused by focusing are distinguishable by surface-consistent patterns. () named this phenomenon focusing-effect AVO (FEAVO). In this paper, I present and discuss the feasibility of a method whose application to FEAVO-affected 2D and 3D datasets would produce an estimate of the anomalies. The goal is to determine a velocity field accurate enough to generate a FEAVO-free prestack volume by downward continuing the wavefield through the FEAVO-generating anomalies. The accurate velocity model should be obtained by using the inversion method known as wave equation migration velocity analysis (WEMVA) (), with a fitting goal modified so that it is specifically geared toward extracting FEAVO effects.

I have continued that line of work by going into more depth with regard to each of the aspects of the study. I will respect the same structure. The material presented at each point consists of the progress in knowledge and research accomplished since the previous paper. I begin with a review of previous work used as a basis for my work, then I explain my approach and show evidence of its validity.