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| Titel |
Reactivity of rock and well in a geological storage of CO2 : role of co-injected gases |
| VerfasserIn |
S. Renard, J. Sterpenich, J. Pironon |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250023289
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| Zusammenfassung |
| The CO2 capture and geological storage from high emitting sources (coal and gas power
plants) is one of a panel of solutions proposed to reduce the global greenhouse gas emissions.
Different pre- , post- or oxy-combustion capture processes are now available to separate
associated gases (SOx, NOx, etc…) and the CO2. However, complete purification of
CO2 is unachievable for cost reasons as well as for CO2 surplus of emissions due
to the separation processes. By consequence, a non-negligible part (more or less
5%) of these gases, called “annex gases”, could be co-injected with the CO2. Their
impact on the chemical stability of reservoir rocks, caprocks and wells has to be
evaluated before any large scale injection procedure. Physico-chemical transformations
could modify mechanical and injectivity properties of the site and possibly alter
storage safety. One of the aims of the CCS pilot project leaded by TOTAL at Lacq
(France) is to develop, through a real case study, a methodology for a long-term
safe storage qualification. Greenhouse gases are captured from an oxy-combustion
power plant, transported along 30 km to the carbonate reservoir of Rousse at around
4500 m in depth. The study presented here is focused on laboratory simulations
of geochemical interactions between the reservoir rock (fractured dolomite), the
caprock (marl) and the injected CO2 with some potential annex gases. In the same
time, experiments are performed on the reactivity of reference minerals such as
calcite, dolomite, muscovite, quartz and pyrite to better understand the implication of
each phase on bulk rock reactivity. Moreover, well reactivity is observed through
specific steel and cement used by petroleum industry. Two annex gases (SO2 and NO)
have been selected.. Their reactivity is compared to that of N2 considered as an
inert annex gas from a chemical point of view. Solid samples are placed in 1cm3
gold capsules in presence or not of water with a salinity of 25 NaCl g/l. Gases
are hermetically transferred by cold trap into the gold reactors that are sealed by
electrical welding and placed in an autoclave during one month at 150˚ C and 100 bar,
which represent the geological conditions in the Rousse reservoir after two years of
injection.
After experiments, solid samples (rock, cement, steel) are observed and analysed with
different techniques (SEM, TEM, Raman and XRD). Gases are also collected and analysed
by Raman spectrometry whereas the aqueous solution is analysed with ICP-MS, ICP-AES
and ionic chromatography. As sampling methods cannot be used during experiment the
synthetic fluid inclusions technique has been developed to trap and analyse the fluids in
experimental conditions. It allows to characterise the number of phase and the nature of
dissolved species. Mass balances are established in order to quantify the reaction
rates.
This study shows the first results concerning the mineralogical transformation of rocks
and well materials that have undergone CO2and co-injected annex gases. The results
are used to better constrain thermodynamical approaches leading to a predictive
geochemical modelling. The results are interpreted in terms of petrophysical and
chemical impacts of the injected gases on the mineral assemblages of a storage
site.
This work is supported by TOTAL and ADEME (national agency for energy control and
development, France). |
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