\section{Discussion}
In our approach, we used the gradual deformation parametrization to obtain our models for both static and dynamic data, however the probability perturbation method \citep{Caers2006} parametrization method could also be applied. Dire quels seraient les avantages ? As the time lapse seismic differences due to the CO_2 injection can be relatively weak or spatially isolated, we argue that it is important to perform full-wave forward modeling to capture most of the physics in the modeled seismic data. However, this step can be very computationally demanding. In this work, we used a Graphical Processing Unit (GPU) accelerated version of the viscoelastic finite-difference time-domain forward modeling of \citep{Bohlen_2002}, which allowed us reducing the run-time by more than 2 orders of magnitude over the original parallel CPU version on a standard workstation.

  