Use and abuse of seismic data in reservoir characterisation

All seismic data contain a mixture of signal and noise. In detailed reservoir characterisation, it is commonly difficult to distinguish between real features and seismic artefacts. This is especially a problem when interpreting seismic attribute maps. Such maps are widely used tools during reservoir description, but serious pitfalls exist, which may lead to erroneous interpretations and fatal development plans for oil fields. A recent interpretation of seismic attribute maps from a seismic survey collected across Gullveig, an oil field located in the northern North Sea, has been used to illustrate how small faults can be recognised and mapped from such maps. We applied available well data (including core data) and two seismic surveys from the same area, and present convincing evidence that the vast majority of linear features seen on the seismic attribute maps are, in fact, seismic artefacts and not faults. The data from Gullveig are furthermore supplemented by observations from the nearby Gullfaks Field and discussions on the topic of seismic noise. We use these observations and discussions to stress the importance of using all available data to guide and quality control the structural interpretation of attribute map features before utilising such interpretations as input to reservoir modelling or well planning. (C) 2001 Elsevier Science Ltd. All rights reserved.