HR: 09:45h
AN: GC31A-08    [PDF]
TI: Carbon Dioxide Sequestration in Fractured Diabase: Experimental Results From Field and Laboratory Studies
AU: * Matter, J M
EM: jmatter@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory of Columbia University, Geochemistry 61 Route 9W, Palisades, NY 10964 United States
AU: Takahashi, T
EM: taka@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory of Columbia University, Geochemistry 61 Route 9W, Palisades, NY 10964 United States
AU: Goldberg, D S
EM: goldberg@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory of Columbia University, Borehole Research 61 Route 9W, Palisades, NY 10964 United States
AB: We investigate the potential of CO$_{2}$ sequestration in basalt aquifers. Such mafic rocks provide cations like magnesium, calcium and iron to solution, which can facilitate precipitation of carbonate minerals from injected CO$_{2}$-saturated fluids and may lead to secure, long-term geological sequestration of CO$_{2}$ from anthropogenic sources. We present results from field and laboratory experiments, including results from small-scale CO$_{2}$ injections into fractured zones in the Palisades Diabase sill and the underlying Triassic sediments of the Newark Basin Series. Geophysical logging and hydrogeological tests conducted prior to the CO$_{2}$ injection experiments indicate several highly fractured zones within the diabase. Porosity varies from less than 3% in massive intervals to maximum 10% in highly fractured zones. Fluid resistivity logs detected water producing and water receiving zones in the diabase. The transmissivity of each of these permeable zones is estimated using flowmeter measurements as well as slug and pump tests to range from 0.0025 to 0.02 m$^{2}$day$^{-1}$. A mixed CO$_{2}$-water injection (pCO$_{2}$ of 1 to 10 bar), with NaCl added as a chemical tracer, into one highly fractured zone isolated in the borehole allows for estimates of the magnitude of flow recovery in the formation. The pH, electrical conductivity and temperature of the injected solution and the flow rate were monitored in real-time. Fluid samples analyzed for major ion chemistry show that the calcium and magnesium concentration in the water increased approximately five times after several days, indicating the neutralization reaction of the CO$_{2}$-saturated injection fluid with the host diabase rock. In addition, laboratory experiments with flow-through columns are performed to investigate the dissolution rates of diabase samples in acidified aqueous solutions with pH 1 to 4 at temperatures 20 to $70\deg$. Comparison of field and laboratory results will be presented and the potential for CO$_{2}$ sequestration in fractured mafic formations will be discussed.
DE: 0915 Downhole methods
DE: 1045 Low-temperature geochemistry
DE: 1829 Groundwater hydrology
SC: Global Climate Change [GC]
MN: 2003 Fall Meeting