Numerical simulation of land subsidence above an off-shore Adriatic hydrocarbon reservoir, Italy, by Data Assimilation techniques
M. Frigo, M. Ferronato, L. Gazzola, P. Teatini, C. Zoccarato
Dept. of Civil, Environmental and Architectural Engineering, University of Padova, Italy
M. Antonelli, A. Corradi, M. C. Dacome, M. De Simoni, S. Mantica
Eni S.p.A., Italy
ABSTRACT
The numerical prediction of land subsidence above producing reservoirs can be affected by a
number of uncertainties, related for instance to the deep rock constitutive behavior,
geomechanical properties, boundary and forcing conditions, etc. The quality and the amount of
the available observations can help reduce such uncertainties by constraining the numerical
model outcome and providing more reliable estimates of the unknown governing parameters.
In this work, we address the numerical simulation of land subsidence above a producing
hydrocarbon field in the Northern Adriatic, Italy, by integrating the available monitoring
data in the computational model with the aid of Data Assimilation strategies. A preliminary
model diagnostic analysis, i.e. the χ2-test, allows for identifying the most
appropriate forecast ensemble. Then, a Bayesian approach, i.e. the Red Flag technique, and
a smoother formulation, i.e. the Ensemble Smoother, provide a significant reduction of the
prior uncertainties. The experiment developed on a real-world gas field confirms that the
integration of monitoring observations with classical geomechanical models is a valuable
approach to improve the reliability of land subsidence predictions and to exploit in a
systematic way the increasing amount of available measurement records.
