ABSTRACT
Isotope and geochemical data is an important tool in
monitoring CO
behaviour in the subsurface in CO
injection projects, such as in enhanced gas recovery
(EGR) projects. Stable isotope data (į
C) combined
with dissolved inorganic carbon (DIC) can be used
to distinguish between their various sources (Barth
et al. 2003). In order to distinguish between already
present and injected inorganic carbon, the end-
member isotope values, i.e. of the injected CO
and
of the dissolved inorganic carbon (į
C
) present
in the aquifer fluid, must clearly differ. Injected
CO
, for instance from power plants, is expected to
have į
C
values ranging between -23 and -33‰.
The baseline į
