A Comparison of Different Geomodeling Approaches in the Context of CO2 Injection and Flow Simulations for the Mt. Simon Sandstone

Abstract

One million tonnes of CO2 was injected into the Mt. Simon Sandstone, a deep saline reservoir, during the Illinois Basin – Decatur Project (IBDP), a large-scale carbon dioxide (CO2) injection and storage demonstration project. During the life of the project, several different Static Earth Models (SEM) were developed for this reservoir, each using different modeling strategies and conceptual geologic models. This study describes four of these SEMs and examines their properties in the context of CO2 injection and flow simulation results. Unlike the original work for IBDP, we did not apply calibration or history matching to the CO2 monitoring data. Thus, CO2 plume development and changes in formation pressure reflect modeling differences, with no intention to replicate the IBDP simulation efforts. Furthermore, for simulation purposes, we introduced an injection well with a 90-ft perforated injection zone above the base of the Lower Mt. Simon and increased the injection rate to one million tonnes of CO2 per year for 3 years. The four models are classified as object based (emulated densely spaced fluvial streams described by various stream geometries); stochastic based (employed neural networks and well logs to derive lithofacies); multipoint facies simulation (implemented a braided-fluvial training image); and porosity mapping (lateral heterogeneity prepared through use of a three-dimensional seismic inversion porosity cube). Considering the differences in facies and petrophysical modeling methodologies, flow simulation results showed that the CO2 plumes were generally constrained to a 762-m (2500-ft) radius around the injection well within the Lower Mt. Simon. At 3 years and 3 million tonnes, the CO2 saturation was compared against porosity and permeability models. This poster will describe the four SEM methods and showcase, side-by-side, flow simulation results depicting the CO2 plume, CO2 saturation, and formation pressure perturbation. We have illuminated the resulting differences among these modeling methods so that geomodelers and reservoir engineers can better understand the benefits and tradeoffs between these SEM approaches. The IBDP is supported by the U.S. Department of Energy-National Energy Technology Laboratory via the Regional Carbon Sequestration Partnership Program (contract No. DE-FC26- 05NT42588) and by a cost-share agreement with the Illinois Department of Commerce and Economic Opportunity, Office of Coal Development, through the Illinois Clean Coal Institute. Acknowledgments We greatly thank the technical support for this research from James R. Damico, Roland T. Okwen, and Charles C. Monson of the Illinois State Geological Survey, Champaign, IL.

AAPG Datapages/Search and Discovery Article #90335 © 2018 AAPG 47th Annual AAPG-SPE Eastern Section Joint Meeting, Pittsburgh, Pennsylvania, October 7-11, 2018