3D Forward stratigraphic modelling of carbonate settings

By

 Kees van der Zwan¹, Henne Lammers¹, Jean Borgomano²

(1) SIEP-SEPTAR, Rijswijk, Netherlands (2) Shell EP Technical Application and Research, Rijswijk, Netherlands

 3D Forward stratigraphic modeling is used to predict the presence and quality of reservoirs, source rocks and seals both on an exploration and production scale. The main input parameters to model any depositional settings are: (1) tectonic subsidence, (2) initial bathymetry, (3) eustatic sealevel and (4) sediment supply. In a carbonate setting this parameter reflects in situ production of carbonate.

In Shell we use the software package DIONISOS, which has been developed in a consortium with IFP. A model was built in DIONISOS for the Cretaceous carbonate platform in the Middle East. Various scenarios were used to test the sensitivity of the main input parameters. 3rd, 4th and 5th order sea level fluctuations were combined with the carbonate growth potential for various “Rudist” platform facies, such as “Rudist” shoals, “Orbitulina” Wackestone and deeper shelf. Evaluation shows that the most important parameter is “accommodation space”. Less impact has changes in carbonate growth potential. For comparison we have build a model for a Tertiary build-up setting.

The above case studies show good matches between the predicted and observed stratigraphy based on seismic and well data. Initial program testing results look promising and suggest forward modelling to be a valuable tool to predict reservoir, source rock and seal distribution both on an exploration and production scale.