Introduction

The seismic reflection method of subsurface imaging is made up of three phases: acquisition, processing and interpretation. Acquisition maps the subsurface geology into the common-shot-gather data space. This space bears little visual relationship to the image space, and its S/N is often poor. Routine processing is therefore applied to enhance the data quality and to convert it to a zero-offset data space. Where geological structuring is gentle, this new space shows a close geometrical relationship to the image space and is often the end product of processing. For more complex geology this space represents a geometrically ``distorted'' image, and further processing is usually needed before a reliable interpretation is attempted. As the relationship between this data space and the image space is defined exactly by the wave-equation, the inverse process becomes possible.

In this report I give a brief mathematical treatment of the Kirchhoff migration algorithm for 2-D seismic data. I illustrate the practical implementation of the process by means of an algorithm that I developed and applied to synthetic seismic data. Furthermore, I show results that I obtained in testing different migration parameters to show the extent of ``distortion'' and the effect of the modeling-imaging procedure.