Depositional Sequence Stratigraphy and Play Fairway Analysis in the Paleogene of the North Sea
FISHER, MICHAEL J., and DAVID C. MUDGE, Nevis Associates Ltd., Helensburgh, Scotland
The Paleogene is a major hydrocarbon play in the North Sea with 18 producing fields and more than 30 further hydrocarbon discoveries. Recent exploration activity has emphasized the potential for stratigraphic trapping to contribute significant reserves. Notwithstanding these successes, these plays remain poorly understood and immature.
Conventional regional analysis is based largely on seismic stratigraphic mapping, which without careful well control is likely to generate significant misties. The resultant lack of precision and the potential for misinterpretation means that this approach on its own is of limited practical application in the North Sea which is a well data-rich area. The generation of a new lithostratigraphic framework, using all available data, is based on the recognition of a series of depositional sequences using wire-line log, biostratigraphic, and seismic criteria. Depositional sequence boundaries correlate with high gamma shale log markers often coinciding with condensed intervals with a strong biostratigraphic fingerprint. These are interpreted as maximum flooding surfaces. These synchronous ev nts can be correlated from basinal to shelfal areas and provide the key for typing the lithostratigraphic and chronostratigraphic framework. The placing of individual reservoir/topseal couples in a chronostratigraphic framework is critical in developing stratigraphic play concepts and producing play fairway maps that show the areas of maximum hydrocarbon prospectivity where all the regional play parameters are favorably combined.
Using this approach in basin analysis has generated new plays that can be evaluated at the local or prospect level. Three plays are illustrated and their future exploration potential highlighted.
AAPG Search and Discovery Article #91004 © 1991 AAPG Annual Convention Dallas, Texas, April 7-10, 1991 (2009)