Abstract: The Influence of Diapiric Topography on the Deposition of Turbidite Sandstones

Al-Ja'aidi, Omar; Knellier, Ben; and McCaffrey, Bill - University of Leeds

Around the world, turbidite sands have become increasingly important reservoir targets for many exploration and production companies. Profitable exploitation of these turbidite reservoirs requires detailed understanding of their geometries and facies distribution. This, in turn, requires an understanding of the factors which controlled turbidity current deposition. Here, we examine the role played by pre existing diapiric sea floor topography.

Submarine fans of Late Paleocene and Early Eocene age form important hydrocarbon reservoirs in the Central North Sea, and provide a good case study of topographic influence, where topography is primarily controlled by the structural evolution and particularly by the halokinesis of the Zechstein salt. Secondary morphological relief was also found to dictate the depositional geometries of subsequent turbidity flows.

Correlation of wireline data from the Central North Sea turbidite reservoirs is frequently hampered by rather subtle log patterns due to the apparently monotonous nature of these deposits, which may lead to ambiguous correlations. Wireline logs calibrated to high density 3-D seismic reflection data have provided valuable insights in describing reservoir areal extent, external geometries, internal fill characteristics, and facies distribution. This combined with the application of new flume-based and theoretical depositional models, together with field observations, has lead to an improved ability in the understanding and prediction of depositional geometries and facies distribution within topographically influenced turbidite systems.

AAPG Search and Discovery Article #90933©1998 ABGP/AAPG International Conference and Exhibition, Rio de Janeiro, Brazil