ENHANCEMENT OF THE GEOLOGICAL FEATURES OF THE SCOTIAN BASIN BY THE APPLICATION OF SPECTRAL INVERSION, OFFSHORE NOVA SCOTIA
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Reflections from the top and bottom of beds thinner than λ/4 cannot be distinguished from one another due to the limit of seismic resolution. It would be advantageous for geoscientists to image thin beds below resolution, especially those which are of reservoir quality. Frequency information obtained from spectral decomposition is related to the temporal thickness of layers. Spectral inversion uses a priori geological information and spectral decomposition to view thin beds below seismic resolution. Spectral inversion is applied to a 3D dataset from the Scotian Basin, on the shelf of Nova Scotia. Two wells, Petro-Can Shell Penobscot L-30 and Shell Petro-Can Penobscot B-41, were drilled in this study area. The L-30 well encountered hydrocarbons within five thin sand beds sealed by intraformational shales. Hydrocarbons were not encountered in the B-41 well, 3.25 km away. Several of these beds, identified on gamma ray logs, were found in both wells and were not visible on the original 3D seismic data. Vertical resolution in this area was improved from 60 m to 21 m. The accuracy of these bed thicknesses was increased using the spectral inversion volume. Some thin beds were able to be mapped which were not previously seen at all on seismic, as well as some small-throw faulting between the wells, improving the imaging of geological features in this area.