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Modeling Carbonate Reservoirs – Past, Present, and Future Trends

Vernon S. Breit
International Reservoir Technologies, Inc., Lakewood, Colorado

The presentation will present an overview of the modeling process for Carbonate reservoirs from the early 1980’s to the present day. Models will be shown from early studies employing single porosity deterministic interpolated mapping of properties to geostatistically based dual porosity models currently being used in the industry.

Emphasis will be placed on the changes in workflows from the early models ( Figure 1 ) -- simple mapping of properties and manual digitization of maps to simulation model grids -- to the more complex models of today ( Figure 2 ) – with property distributions based on seismic attributes and object modeling to distribute matrix and fracture properties. Through the examples presented the length of time to “complete” studies in the 80’s, 90’s, and currently will be presented. Finally, a discussion of what is needed in the future to increase the usage of modeling in carbonate reservoirs will be presented.

The presentation will briefly present two west Texas carbonate reservoir model studies of the early 1980’s, 2 middle east carbonate reservoir studies of the late 1990’s, and one Mexican and one middle Eastern dual porosity modeling study from the last 2 years. The methodology used in each study will be highlighted along with the time needed to complete each study.

In all cases the author will emphasize the kind of “practical” assumptions and workflow compromises that were necessary to complete the studies in a “reasonable” time-frame. 

Figures of properties, matches, and predictions from the studies will be presented that highlight the techniques used in the studies.

Figure 1- Integrated Studies- 1980 Practice

Figure 2- Integrated Studies – 2000’s Concept