This paper examines the results obtained from several sets of experimental
work conducted on cement deterioration in environments similar to those found
in CO2 injection and storage projects.
In order to investigate various changes in macroscopic and microscopic
properties and behaviour of cement in presence of sulphate ions and
CO2, several sets of experiments were conducted.
The study consisted of preparing and investigating the behaviour of several
hundred samples of cement in presence of various concentrations of sulphate,
from 0.1 wt% up to 6%, as well as CO2 at 15160 kPa and 55ºC.
The effect of sulphate ions on cement was studied at 30ºC, 55ºC and 75º C. The
two common classes of cement of Type 10 and Class G were tested during this
study. A total of 300 identical cubic and 400 identical cylindrical samples
were tested. The change in permeability, compressive strength, and shear and
hydraulic bonding strength for these samples were monitored after 2, 4, 6, 8,
10 and 12 months.
Laboratory results showed that sulphate ions and CO2 improve the
performance of cement during the first few months. However, the effect is
reversed under prolonged experiments. The highest reduction in performance was
observed for hydraulic shear bonding, which indicates that the highest risk of
CO2 leakage is through pathways between the cement and casing.
© 2010. Society of Petroleum Engineers
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- Original manuscript received:
23 June 2009
- Meeting paper published:
18 June 2008
- Revised manuscript received:
29 July 2010
- Manuscript approved:
18 August 2010
- Published online:
1 October 2010
- Version of record:
1 October 2010