Injection of CO2-Saturated Water through a Siliceous Sandstone Plug from the Hontomin Test Site (Spain): Experiment and Modeling

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• 作者：J. Canal ; J. Delgado ; I. Falc贸n ; Q. Yang ; R. Juncosa ; V. Barrientos
• 刊名：Environmental Science & Technology (ES&T)
• 出版年：2013
• 出版时间：January 2, 2013
• 年：2013
• 卷：47
• 期：1
• 页码：159-167
• 全文大小：476K
• 年卷期：v.47,no.1(January 2, 2013)
• ISSN：1520-5851

文摘

Massive chemical reactions are not expected when injecting CO₂ in siliceous sandstone reservoirs, but their performance can be challenged by small-scale reactions and other processes affecting their transport properties. We have conducted a core flooding test with a quartzarenite plug of Lower Cretaceous age representative of the secondary reservoir of the Hontom铆n test site. The sample, confined at high pressure, was successively injected with DIW and CO₂-saturated DIW for 49 days while monitoring geophysical, chemical, and hydrodynamic parameters. The plug experienced little change, without evidence of secondary carbonation. However, permeability increased by a factor of 4 (0.022鈥?.085 mD), and the V_P/V_S ratio, whose change is related with microcracking, rose from 1.68 to 1.8. Porosity also increased (7.33鈥?.1%) from the beginning to the end of the experiment. Fluid/rock reactions were modeled with PHREEQC-2, and they are dominated by the dissolution of Mg-calcite. Mass balances show that 4% of the initial carbonate was consumed. The results suggest that mineral dissolution and microcracking may have acted in a synergistic way at the beginning of the acidic flooding. However, dissolution processes concentrated in pore throats can better explain the permeability enhancement observed over longer periods of time.