Patent ID: 6832160
Filing Date: 2004-12-14
Classification: G01V

Abstract:
A method for finding the Reflection Coefficient (RC) of reflectors in illuminated areas of the subsurface of the ground, comprising:a) migrating to depth recorded traces in a survey by Pre-Stack Depth Migration (PSDM), using shot/receiver pairs, to obtain a real depth migrated seismic cube PObs({right arrow over (x)}) which is a function of the recorded traces that have each been given a weight wi({right arrow over (x)}); b) interpreting PObs({right arrow over (x)}) to find the spatial positions of the reflectors in the subsurface, and based on these reflectors and the seismic velocities, a depth model is established in the computer, wherein one of the reflector surfaces in the depth model is chosen to be the target reflector; c) computing synthetic traces from the target reflector for all shot/receiver pairs by setting the RC of the target reflector in the depth model to an essentially constant value when the synthetic traces are computed; d) performing a local PSDM of the computed synthetic traces in a band around the target reflector to obtain a modeled synthetic PSDM cube PMod({right arrow over (x)}) locally around the target reflector; and e) measuring the amplitudes along the target reflector from the real PSDM cube PObs({right arrow over (x)}), and dividing these amplitude measurements by the corresponding amplitude measurements from the modeled PSDM cube PMod({right arrow over (x)}), to thereby obtain discrete estimates of the angle dependent RC for all illuminated areas of the target reflector and a weight function for all discrete estimates of the RC along the target reflector.