The impact of pre‐stack data phase on the AVO interpretation workflow

Abstract

In the conventional approach of interpreting stacked seismic data, it is quite common to rotate the phase of the data to match synthetic correlations and/or to get isolated reflections in the data as close as possible to zero phase. Understanding the phase of the data is extremely important in the interpretation workflow and has significant implications for the final interpretation and drilling of wells. This functionality is available on most interpretation systems today. What is not routine in the normal interpretation process is to phase rotate gathers to determine how this affects the final stacked volume, the analysis of the pre‐stack data, and ultimately the final interpretation of the prospect. Depending on the phase of gathers, the generation of various AVO attributes for crossplotting can produce varied results, which may adversely obscure or highlight significant trends in the data. From a 3D data set in the shallow waters offshore Louisiana, an AVO interpretation of pre‐stack gathers and AVO crossplots was found to be quite beneficial in understanding the phase of the data and its impact on defining acoustic reservoir thickness.