Skip to main content

Pore-Scale Investigation of the Impacts of Solution Chemistry on Mixing-Induced Mineral Precipitation in Silicon-Based Micromodels


EMSL Project ID
38008

Abstract

CO2 sequestration in geologic formations is increasingly being studied as a strategy for limiting CO2 emission to the atmosphere, but there are potentials for geochemical reactions in the reservoirs and uncertainties associated with the environmental impacts. Reactions between dissolved CO2 and cations in groundwater (e.g., Ca2+, Mg2+) may cause mineral precipitation, and hence reductions in permeability and loss of injectivity. In this study, microfluidic pore structures etched into silicon wafers will be used as two-dimensional model groundwater systems (i.e., micromodels) to study the impacts of solution chemistry on mechanisms of mineral precipitation relevant to CO2 sequestration. Solutions containing CaCl2 and Na2CO3 will be introduced through two separate inlets and they mix along the center of the micromodel. Images of the micromodel will be taken using a microscope equipped with a digital camera at selected time points. Calcite formation rates and morphology along the mixing zone will be determined from images and the impacts of solution pH, ionic strength and presence of Mg2+ on reaction rates and morphology will be investigated. Results from this study will elucidate mineral precipitation reaction mechanisms in complex geochemical systems and provide insights into potential impacts of CO2 sequestration.

Project Details

Project type
Exploratory Research
Start Date
2010-02-04
End Date
2011-02-06
Status
Closed

Team

Principal Investigator

Changyong Zhang
Institution
ExxonMobil Research and Engineering

Team Members

Karl Dehoff
Institution
Pacific Northwest National Laboratory

Related Publications

Zhang C, KJ Dehoff, NJ Hess, M Oostrom, TW Wietsma, AJ Valocchi, BW Fouke, and CJ Werth. 2010. "Pore-Scale Study of Transverse Mixing Induced CaCO3 Precipitation and Permeability Reduction in a Model Subsurface Sedimentary System." Environmental Science & Technology 44(20):7833-7838. doi:10.1021/es1019788