|
|
 |
|||||||||||||||||
|
|||||||||||||||||
 |
|||||||||||||||||
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |
1 U.S. Geological Survey, MS/427, 345 Middlefield Rd., Menlo Park, California 94025, USA
2 Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
3 Bureau of Economic Geology, University of Texas, Austin, Texas 78713, USA
4 Alberta Research Council, Edmonton, Alberta T6N 1E4, Canada
5 Lawrence Livermore National Laboratory, Livermore, California 94550, USA
6 Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
To investigate the potential for the geologic storage of CO2 in saline sedimentary aquifers, 1600 t of CO2 were injected at 1500 m depth into a 24-m-thick sandstone section of the Frio Formation, a regional brine and oil reservoir in the U.S. Gulf Coast. Fluid samples obtained from the injection and observation wells before CO2 injection showed a Na-Ca-Cl–type brine with 93,000 mg/L total dissolved solids (TDS) at near saturation with CH4 at reservoir conditions. Following CO2 breakthrough, samples showed sharp drops in pH (6.5–5.7), pronounced increases in alkalinity (100–3000 mg/L as HCO3) and Fe (30–1100 mg/L), and significant shifts in the isotopic compositions of H2O, dissolved inorganic carbon (DIC), and CH4. Geochemical modeling indicates that brine pH would have dropped lower but for the buffering by dissolution of carbonate and iron oxyhydroxides. This rapid dissolution of carbonate and other minerals could ultimately create pathways in the rock seals or well cements for CO2 and brine leakage. Dissolution of minerals, especially iron oxyhydroxides, could mobilize toxic trace metals and, where residual oil or suitable organics are present, the injected CO2 could also mobilize toxic organic compounds. Environmental impacts could be major if large brine volumes with mobilized toxic metals and organics migrated into potable groundwater. The 
18O values for brine and CO2 samples indicate that supercritical CO2 comprises 
50% of pore-fluid volume 6 mo after the end of injection. Postinjection sampling, coupled with geochemical modeling, indicates that the brine gradually will return to its preinjection composition.
Key Words: CO2 storage • global warming • basinal formation water • chemical composition of fluid • Frio Formation
This article has been cited by other articles:
|
|
 |
|
  F. M. Orr Jr. Onshore Geologic Storage of CO2 Science, September 25, 2009; 325(5948): 1656 - 1658. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Wilkinson, R. S. Haszeldine, A. E. Fallick, N. Odling, S. J. Stoker, and R. W. Gatliff CO2-Mineral Reaction in a Natural Analogue for CO2 Storage--Implications for Modeling Journal of Sedimentary Research, July 1, 2009; 79(7): 486 - 494. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Zhu Geochemical Modeling of Reaction Paths and Geochemical Reaction Networks Reviews in Mineralogy and Geochemistry, January 1, 2009; 70(1): 533 - 569. [Full Text] [PDF]
|
|
|
|
 |
|
 S. M. Benson and D. R. Cole CO2 Sequestration in Deep Sedimentary Formations Elements, October 1, 2008; 4(5): 325 - 331. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. J. Houston, B. W.D. Yardley, P. C. Smalley, and I. Collins Rapid fluid-rock interaction in oilfield reservoirs Geology, December 1, 2007; 35(12): 1143 - 1146. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. J. Friedmann Geological Carbon Dioxide Sequestration Elements, June 1, 2007; 3(3): 179 - 184. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 W. T. Parry, C. B. Forster, J. P. Evans, B. B. Bowen, and M. A. Chan Geochemistry of CO2 sequestration in the Jurassic Navajo Sandstone, Colorado Plateau, Utah Environmental Geosciences, June 1, 2007; 14(2): 91 - 109. [Abstract] [Full Text] [PDF]
|
|
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |
