Seismic Attenuation from VSP and Well Log Data - NW Shelf Australia Case Study

Abstract

Seismic attenuation is an important contributor to the overall amplitude decay of the seismic wave travelling through the medium. Seismic attenuation anomalies in the overburden can both mask amplitude changes at the target horizons and carry important information about presence of free gas or overpressure. In order to understand the pattern and principal causes of the attenuation in one geographical area, specifically, one of the Australian North-West shelf’s basins, we examine a relatively large number of wells coming from this area using one consistent workflow. The dataset includes recent wells with high quality zero-offset (rig) VSP and good well log coverage.