The Differentiation Mapping of Oil Gravity Using Amplitude Variation with Offset, Hebron Ben Nevis Field, Offshore Newfoundland, Canada

Andrew John Royle

This paper investigates the amplitude variation with offset (AVO) behaviour at the Ben Nevis reservoir zone in an attempt to predict API oil gravity variations. Intercept, gradient, fluid factor, and density reflectivity attribute volumes were extracted to observe the AVO effects at the reservoir zone. These attributes isolated the oil zones associated with the Ben Nevis reservoir and showed differences between the adjacent fault block reservoir zones. Detailed crossplotting at the oil bearing well locations isolated anomalous zones associated with the response at the top of the reservoir. Simultaneous inversion methods were applied to the dataset, which provided useful information on the nature of the lithology and pore fluids. The AVO and inversion attributes were then used as inputs in a neural network analysis for porosity and fluid density. The porosity volume correlated closely with the well data across the asset and the fluid density volume accurately portrayed the variations in oil density across the asset.