Large-Scale Impact Of Co2 Storage Operations: Dealing With Computationally Intensive Simulations For Global Sensitivity Analysis

Assessing the potential impacts associated with CO2 storage operations implies using large-scale models characterized by a very large number of grid cells (> 500,000) and high computation time cost (> several hours). Yet, investigating the influence of the input parameters on the model results requires multiple simulations (> 1,000), which might become impracticable due to the computation burden. A meta-modelling strategy is then proposed, basically consisting in approximating the long running model by a costless-to-evaluate model, for instance a Gaussian Process, based on a very limited number of simulations (e. g., 50). This strategy is tested to investigate the sensitivity of the overpressure induced by an industrial-scale CO2 injection into a fluvial heterogeneous reservoir, to the properties of the shale formation using a 3-dimensional long running multiphase flow model (with CPU time > 5 days). (C) 2013 The Authors. Published by Elsevier Ltd.