Data assimilation of SAR-based measurements for geomechanical characterization

Fluid injection into the subsurface is becoming increasingly popular worldwide in connection with Underground Gas Storage (UGS). Due to the pressure variations caused by fluid injection and extraction, porous rock formations are subject to significant seasonal changes of stress fields and, subsequently, of the displacement fields.Ageomechanical model based on a non linear transversely isotropic stress-strain constitutive law is used to model surface displacements over an existing gas reservoir located in Northern Italy. Using the Ensemble Smoother (ES) data assimilation technique, InSAR measurements of horizontal and vertical surface displacements are jointly assimilated to constrain and reduce the uncertainty of the model parameters.