assess cross-formational leakage
and ultimately leakage to the land surface.
A similar analytical treatment for the case of CO2 injection is significantly more challenging because of the nonlinearities inherent in the two-phase flow system,
and the complex interactions between injection and potentially leaking wells.
While the overall framework follows that of Nordbotten et al. (2004),
each of the individual aspects, such as plume evolution,
leakage through one or more wells,
and number of aquifers and aquitards in the sedimentary succession,
requires more effort to develop and implement.