Pre-stack diffraction Imaging and its application in hard rock environment

Abstract

Exploration for mineral deposits in a predominately hard rock environment is often quite difficult because of structural complexities of rocks such as faults, fracture zones, intrusives and steep dips. Many mineral deposits are related to these structures. Therefore, detecting such complexities is of a primary interest in in mineral exploration. Faults and intrusions scatter seismic energy in a form of diffraction and can be detected through a process known as "Diffraction Imaging". Post stack diffraction imaging has been successfully applied in hard rock environment. As a continuation of the development of this methodology, we propose a pre stack diffraction imaging algorithm in order to extract more information than is possible with post stack diffraction imaging. Proposed technique separates diffractions from reflections by clipping the area tangency around the apexes of reflections, defined by Fresnel zone, in CMP-offset domain. The performance of the method is demonstrated on both 2D synthetic and field seismic data collected over a well-known mineral system in South Australia.