Properties of CO2-Rich Pore Fluids and Their Effect on Porosity Evolution in EGS Rocks Geothermal Lab Call Project

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Last modified on July 22, 2011.

Project Title Properties of CO2-Rich Pore Fluids and Their Effect on Porosity Evolution in EGS Rocks
Project Type / Topic 1 Laboratory Call for Submission of Applications for Research, Development and Analysis of Geothermal Technologies
Project Type / Topic 2 Supercritical Carbon Dioxide / Reservoir Rock Chemical Interactions
Project Description While geologic CO2 sequestration and geothermal energy production are increasingly viewed as central to a sustainable energy future, existing models of fluid properties and their effect on reservoir rocks are grossly inadequate for CO2-rich systems under EGS conditions. We propose a suite of innovative complementary studies designed to address the principal weaknesses of current models, which are a lack of accurate fluid properties in the relevant pressure, temperature, and composition ranges, an inability to predict the migration of such fluids through the fracture/pore environment over variable length scales; and no provision in current models for the effects of adsorption and fluid confinement. These shortcomings preclude accurate predictions of the most important processes underpinning reservoir performance: reservoir hydrodynamics and fluid-rock mass transfer, the latter of which catalyzes porosity/permeability evolution, which in turn may effectively enhance heat mining.
State Tennessee
Objectives Quantify key parameters critically needed for developing and validating numerical modeling of chemical interactions between EGS reservoir rocks and supercritical CO2 and CO2-rich aqueous fluids.
Awardees (Company / Institution) Oak Ridge National Laboratory

Funding Opportunity Announcement DE-PS36-09GO99017
DOE Funding Level (total award amount) $1,000,000.00
Total Project Cost $1,000,000.00

Principal Investigator(s) David R. Cole

Targets / Milestones Using four complementary approaches to improve predictive geochemical modeling by addressing the problems described above:

- Characterization of CO2+H2O bulk and pore fluids by vibrating tube densimetry (VTD)
- Determination of changing pore and fluid structures using a combination of small angle and ultra-small angle neutron scattering (SANS and USANS).
- Real time imaging of the advancing fluid front and evolution of porosity using X-ray and neutron tomography (XCT and NCT).
- Linking these synergistic experimental efforts through development of new equations of state (EOS) for bulk and pore-confined fluids involving typical EGS reservoir rocks and environmental conditions.

Location of Project Oak Ridge, TN

Funding Source American Recovery and Reinvestment Act of 2009
References EERE Geothermal Technologies Programs[1]


  1. EERE Geothermal Technologies Programs