ROCK/CEMENT PERMEABILITY UNDER CONDITIONS RELEVANT TO SUBSURFACE DISPOSAL OF CARBON DIOXIDE

Robert G. Bruant, Jr.*
Andrew J. Duguid
Mileva Radonjic
George W. Scherer
Michael A. Celia
Program in Environmental Engineering and Water Resources
Department of Civil and Environmental Engineering
Princeton University
Princeton, NJ 08544
Voice: 609-258-4599
Fax: 609-258-2760
E-mail: rbruant@princeton.edu

Charles A. Christopher
BP America Inc.
Houston TX

Injection and subsurface containment of CO₂ is being considered as an alternative to atmospheric emission, but abandoned oil and gas wells may act as conduits for vertical CO₂ migration and atmospheric release. A long-term study is underway to test the stability of rock (Salem limestone and Berea sandstone), cement, and the cement/stone interface under conditions relevant to subsurface CO₂ sequestration. In this paper, we will report on the effects of curing regime on the permeability of the paste. The measurements use a novel technique, beam-bending, that provides rapid results. When a saturated rod of paste is subjected to three-point bending, a pressure gradient is created in the pore liquid, resulting in flow within the sample. As the pore pressure equilibrates, the force required to sustain a fixed deflection of the rod decreases. By analyzing the kinetics of the force relaxation, the permeability can be determined. In addition, preliminary chemical characterization will be presented for cement paste exposure to high-pressure aqueous/CO₂ (PCO₂ = 100 bar) environments.