An Integrated Experimental and Numerical Study: Developing a Reaction Transport Model that Couples Chemical Reactions of Mineral Dissolution/Precipitation with Spatial and Temporal Flow Variations in CO2/Brine/Rock Systems Geothermal Project

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Last modified on July 22, 2011.

Project Title An Integrated Experimental and Numerical Study: Developing a Reaction Transport Model that Couples Chemical Reactions of Mineral Dissolution/Precipitation with Spatial and Temporal Flow Variations in CO2/Brine/Rock Systems
Project Type / Topic 1 Recovery Act: Enhanced Geothermal Systems Component Research and Development/Analysis
Project Type / Topic 2 Supercritical Carbon Dioxide / Reservoir Rock Chemical Interactions

Project Description This project will result in a numerical simulator (modified version of TOUGH2) that can adjust porosity and permeability fields according to experimentally observed chemical fluid-rock interactions (mineral dissolution/precipitation) under realistic conditions likely found when supercritical CO2 is injected into geothermal reservoirs for heat energy extraction. The simulator can thus help determine if CO2 injection into EGS brines will cause clogging of pore spaces or dissolution of host rocks with potentially detrimental consequences to heat extraction. As a result, this simulator will play a critical role when assessing long-term sustainability of geothermal energy utilization in enhanced and natural geothermal systems. The simulator can also be used to evaluate long-term CO2 sequestration potentials.
State Minnesota
Objectives Modify a numerical simulator (TOUGH2) to allow coupling of experimentally observed chemical interactions between supercritical carbon dioxide (CO2) and enhanced geothermal system (EGS) reservoir rocks with spatial and temporal variations in pore/fracture geometries and in associated permeability and flow fields.
Awardees (Company / Institution) University of Minnesota
Legal Name of Awardee Regents of the University of Minnesota
Awardee Website http://www.geo.umn.edu/











Funding Opportunity Announcement DE-FOA-0000075

DOE Funding Level (total award amount) $1,550,018.00
Awardee Cost Share $387,505.00
Total Project Cost $1,937,523.00



Principal Investigator(s) Martin O. Saar
Other Principal Investigators William E. Seyfried and Ellen K. Longmire

Targets / Milestones The chemical interactions studied are predominantly mineral dissolution/precipitation reactions that are likely heterogeneously distributed and time-dependent. Thus, standard chemical models that assume homogeneously mixed components, local equilibrium, and evenly distributed pore structures cannot be applied. Instead, this study will conduct physical experiments involving the actual fluids (brine, supercritical CO2) and solids (various likely reservoir rocks) under realistic pressure and temperature conditions. These experiments are then utilized in the manner described next to include mineral dissolution/precipitation processes and related perme-ability changes into TOUGH2 for conditions that are likely found when supercritical CO2 is used in EGS.




Location of Project Minneapolis, MN



Impacts If successful, the investigation will provide insights into the behavior and effects of supercritical C02 in EGS reservoirs. 3-D imagine of mineral surfaces will provide insights into unknown dissolution and percipitation processes within the CO2-H20 EGS system.
Funding Source American Recovery and Reinvestment Act of 2009

References EERE Geothermal Technologies Programs[1]

References

  1. EERE Geothermal Technologies Programs