Solution of high velocity anomalies imperceptible to seismic resolution, by means of synthetic models, penobscot field, canada

Abstract

Penobscot Field is located in the Sable Sub-basin in Nova Scotia, Canada, where a 3D seismic acquisition campaign was carried out in 1991 and also two oil wells were previously drilled (L-30 and B-41). In the interpreted seismic data, a discrepancy was found in the travel times of the seismic waves near well B-41, causing a false structural height in the Naskapi Member, Mississauga Formation (Early Cretaceous or Lower Cretaceous) and deeper formations (10 to 15 ms, i.e. approximately 25 m). It was decided to fnd a solution of this problem using synthetic models. First, making a delimita-tion of the study area by means of a seismic subcube, which were later interpreted surfaces of interest, through the well data. The average velocity and density properties were found for each interpreted strata. Subsequently, a 2D seismic acquisition was simulated, choosing a line that crossed both wells and through the use of ray traces, synthetic shot gathers were obtained and processed through the use of diferent seismic migration tests, and the fnal solution was found to be Kirchhof pre-stacking migration in depth.