Integrative ArcGIS mapping study of direct hydrocarbon indicators within the Shelburne Subbasin of the Scotian Slope, Nova Scotia

Abstract

Seepage data can provide evidence for hydrocarbon migration from underlying mature source rocks. In this study, ArcGIS coupled with seismic analysis of the Shelburne 3D seismic survey is used to better constrain the prospectivity of petroleum systems underlying the Scotian Slope. In this study, the seismic attributes root mean square amplitude (RMS) and coherence were used to identify near-surface expressions of hydrocarbon migration from the Shelburne 3D seismic volume. The RMS amplitude maps reveal amplitude anomalies including direct hydrocarbon indicators (DHIs) above salt features that are likely related to the presence of hydrocarbon-bearing sediments. Coherence maps were used to highlight seafloor and subsurface discontinuities such as paleo-pockmarks and polygonal faults, which are subsurface fluid escape mechanisms. The DHIs are commonly associated with these fluid escape structures. The presence of these two features suggest hydrocarbons are migrating from deeper within the Shelburne Subbasin implying the presence of an active petroleum system within the deeper Scotian Slope.