JACQUIN,THIERRY, Universitè de Paris-Sud XI, Orsay, France; and MARK THOMSEN, Mobil Exploration Norway Inc., Stavanger, Norway

Abstract: 3 Dimensional Stratigraphic Modelling of the Northern North Sea

Sequence stratigraphy is a powerful technique for building a high-resolution framework over even large-size datasets. Unfortunately the increase in stratigraphic resolution does not necessarily mean increase in an understanding for the average scientist or manager who must work with the study. However, since the dataset has a uniform grid (in X and Y) it can be stored as a 3D matrix file and visualized as a whole. Using the stratigraphic data as a framework, we have built a 4 dimensional matrix to visualize stratigraphic features, where each cell of the model has 4 coordinates: X,Y,Z,T (T for time in Ma). The most important variable is not anymore the depth to a particular horizon as in standard 3D matrix visualization techniques, but the time in Ma.

This technique has been applied at various scales, from the reservoir up to the regional scale. We are presenting a 4 dimensional stratigraphic model of the Northern North Sea area between 60° and 62°N, 1° and 4.5°E, covering 200 Ma from the top Statfjord Formation to the sea-bottom. Major first- and second-order Transgressive/Regressive cycles can be visualized in 3D, with a full spectrum of colors corresponding to their age and duration in Ma. Lowstand basin deposits and/or aggradational shelfal deposits are delimited by isochrone surfaces and not isobaths like standard 3D techniques. One of the application is the analysis of sedimentation rates, in the three dimensions and per time unit. Sediment flux is significantly changing, which controls the timing of major peak transgressions and regressions.

AAPG Search and Discovery Article #90923@1999 International Conference and Exhibition, Birmingham, England