Characterization of Deltaic Rocks for Numerical Reservoir Simulation Purposes

MIJNSSEN, F. C. J., TNO Institute of Applied Geoscience, Delft, The Netherlands, and K. J. WEBER and A. W. MARTINIUS, Delft University of Technology, Delft, The Netherlands

To predict the production behavior of deltaic reservoirs, use can be made of numerical simulation models. The reliability of these models largely depends on the accuracy of the description of the reservoir architecture and the spatial variability of rock properties.

A methodology for building a data base for quantitative prediction of reservoir architecture and permeability distribution has been developed. This methodology uses data from recent environments, outcrops, and densely drilled fields. Examples of data collection will be shown from the Recent Atchafalaya delta (Louisiana), outcrops of Tertiary sandstones in the Loranca basin (Spain), and the Frio Formation of the North Markam-North Bay City field (Texas). A study has been made of the specific characteristics of deltaic genetic units. It was found that the 26 genetic units recognized can be represented by only 8 basically different models with respect to fluid flow. The scale of these flow elements compares with the size of reservoir simulation grid blocks commonly used. For each type of elementary flow unit, characteristic horizontal and vertical permeability anisotropies were established. These can be used to derive pseudo horizontal and vertical permeabilities for simulation grid blocks. Examples will be shown of the use of the permeability anisotropies in numerical simulation experiments.

AAPG Search and Discovery Article #91004 © 1991 AAPG Annual Convention Dallas, Texas, April 7-10, 1991 (2009)