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Simulating the Stratigraphic Evolution of a Jurassic Carbonate Ramp Outcrop Analog Using the Forward Stratigraphic Model Dionisos

Pierre, Aurelien O.1; Jones, Gareth D.1; Harris, P. Mitch 1; Durlet, Christophe 2
1 CHEVRON, San Ramon, CA.
2 Biogeosciences, Universite de Bourgogne, Dijon, France.

A continuous 37 km seismic scale dip orientated exposure of Jurassic age carbonates located near Amellago in Morocco provides a world class outcrop analog for Mesozoic carbonate ramp reservoirs. The evolving ramp geometry captures inner and outer ramp facies including reservoir prone ooid facies. A high resolution sequence stratigraphic framework has previously been described by Pierre et al. (2006).

We utilized the Amellago ramp to evaluate the forward stratigraphic model DIONISOS to simulate the stratigraphic evolution of a carbonate ramp reservoir. Specifically we tested: 1) The impact of user specified eustatic cyclicity at the resolution of 3rd order and 4th orders; 2) Sensitivity to rates of carbonate production based on water depth and wave energy and sediment transport and 3) Sensitivity of the simulated stratigraphy to the specified model time step and grid cell dimensions. Comparative analyses indicate that DIONISOS can adequately model the stratigraphic evolution of a carbonate ramp reservoir. Incorporation of 4th order eustatic cycles resulted in greater facies heterogeneity, reduced reservoir facies connectivity and a stratigraphic architecture closer to that observed. Failure of diffusive transport routines to simulate sediment transport by tidal currents accounts for certain discrepancies relative to observed stratigraphy. Results proved sensitive to specified time step increment and grid size, which were optimized at 0.05 My and 0.5 km respectively. Further sensitivity studies and quantitative interrogation of model results are being undertaken to generate digital analogs and improve the conditioning of carbonate ramp reservoir models for flow simulation.


AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009