Sustainable underground gas storage activities in a Po plain gas field, northern Italy
N. Castelletto, M. Ferronato, G. Gambolati, C. Janna, P. Teatini
Dept. Mathematical Methods and Models for Scientific
Applications, University of Padova, Padova, Italy
D. Marzorati, E. Cairo
Stogit S.p.A., San Donato Milanese, Italy
D. Colombo, A. Ferretti
Tele-Rilevamento Europa S.r.l. (TRE), Milano, Italy
A. Bagliani, F. Bottazzi
Eni S.p.A. - Divisione E&P, San Donato Milanese, Italy
ABSTRACT
The present communication describes a multidisciplinary approach to evaluate the
sustainability of the underground gas storage (UGS) programs in a Po Plain gas field,
northern Italy. Long-time records of injected/removed gas volume and fluid pore pressure
together with multi-year measurements of vertical and horizontal land displacements by an
advanced PSInSAR technique allow for the development of representative 3D fluid-dynamic
and transversally isotropic geomechanical models. The latter is successfully implemented to
simulate both the vertical and horizontal cyclic motions, on the range of 8-10 mm and 6-8
mm, respectively, measured between 2003 and 2007 over the field. The calibrated models
are then used to predict the ground displacements in connection with two UGS future
scenarios where the injected gas is increased from the original in-situ value pi
to 107%pi and 120%pi. These programs are of the
greatest importance as they allow for an increase of the
stored gas volume by more than 240% relative to the current storage value at pi. The results
show that the planned UGS developments have a small impact as they generate very
modest ground movements, with displacement gradients well below the most severe bounds
recommended to preserve the overland structure and infrastructure integrity.
