Computational studies of two-phase cement-CO2-brine interaction in wellbore environments [electronic resource].
- Washington, D.C. : United States. Dept. of Energy, 2009. and Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
- Additional Creators:
- Los Alamos National Laboratory, United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information
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- Free-to-read Unrestricted online access
- Wellbore integrity is essential to ensuring long-term isolation of buoyant supercritical CO₂ during geologic sequestration of CO₂. In this report, we summarize recent progress in numerical simulations of cement-brine-CO₂ interactions with respect to migration of CO₂ outside of casing. Using typical values for the hydrologic properties of cement, caprock (shale) and reservoir materials, we show that the capillary properties of good quality cement will prevent flow of CO₂ into and through cement. Rather, CO₂, if present, is likely to be confined to the casing-cement or cement-formation interfaces. CO₂ does react with the cement by diffusion from the interface into the cement, in which case it produces distinct carbonation fronts within the cement. This is consistent with observations of cement performance at the CO₂-enhanced oil recovery SACROC Unit in West Texas (Carey et al. 2007). For poor quality cement, flow through cement may occur and would produce a pattern of uniform carbonation without reaction fronts. We also consider an alternative explanation for cement carbonation reactions as due to CO₂ derived from caprock. We show that carbonation reactions in cement are limited to surficial reactions when CO₂ pressure is low (< 10 bars) as might be expected in many caprock environments. For the case of caprock overlying natural CO₂ reservoirs for millions of years, we consider Scherer and Huet's (2009) hypothesis of diffusive steady-state between CO₂ in the reservoir and in the caprock. We find that in this case, the aqueous CO₂ concentration would differ little from the reservoir and would be expected to produce carbonation reaction fronts in cements that are relatively uniform as a function of depth.
- Published through SciTech Connect., 01/01/2009., "la-ur-09-05560", " la-ur-09-5560", SPE International Conference on CO2 Capture & Storage ; November 2, 2009 ; San Diego, CA., and Carey, James William; Lichtner, Peter C.
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