Processing, imaging, interpretation, and image analysis of seismic lines acquired offshore Nova Scotia, Canada

The Scotian Basin is a region of varied geological structures including a large carbonate bank complex, salt diapirs, and extensional faulting. Two seismic lines acquired in this area were examined in this study. For each line, seismic processing was followed by prestack and poststack time and depth migrations to determine an ideal imaging flow for the geological environments sampled. Features imaged were interpreted in the context of the regional geological history. Images were analyzed in detail to ascertain the sensitivity of image positioning in time and depth migration as a function of lateral velocity variation, and also the influence of reflector dip on quality of images obtained from prestack and poststack migration. It is shown that positional differences are apparent between time and depth migrations when lateral RMS velocity contrasts are 15% and higher and that prestack migrations produce superior images than poststack migrations for events that dip 15 degrees or greater.