Characterization and 3-D Modeling of Devonian Pinnacle Reefs for CO₂ Storage and Enhanced Oil Recovery

Abstract

The Energy & Environmental Research Center, through the Plains CO₂ Reduction Partnership Program, has characterized various Devonian-aged pinnacle reefs in the Zama Member of the Muskeg Formation and the Keg River Formation in the Western Canada Sedimentary Basin and the Winnipegosis Formation in the Williston Basin for potential CO₂ storage and CO₂ enhanced oil recovery. These pinnacle reefs were characterized by constructing 3-D geocellular models using a database containing geologic interpretations, well logs, and core data. The geologic models were constructed by first building structural surfaces, populating a facies model, and then performing geostatistical analysis on reservoir properties. Finally, the models were passed on to dynamic simulation for predictions. These Devonian pinnacle reefs have been altered by diagenetic processes and cemented by anhydrite deposits, creating complex geometry and heterogeneous internal facies. In addition, these pinnacle reefs vary widely in size depending on the conditions during deposition. Thus structural models were built to capture a wide variety of sizes and internal architecture. Multiple-point statistics were used to construct facies models based on geologic interpretations that honor well data and reservoir properties were then conditioned to each facies model. The models were prepared for dynamic simulations, which calculated the total CO₂ storage of 5000–10,000 metric tons for each pinnacle, with up to 1000% additional storage when optimization techniques were utilized. The approach utilized in this study will allow others to more efficiently construct pinnacle reef models and perform predictive simulations to determine the potential for oil recovery and/or CO₂ storage.

AAPG Datapages/Search and Discovery Article #90193 © 2014 Rocky Mountain Section AAPG Annual Meeting, Denver, Colorado, July 20-22, 2014