Parameter estimation of subsurface flow models using iterative regularized ensemble Kalman filter

A. H. ELSheikh, C. C. Pain, F. Fang, J. L. M. A. Gomes, I. M. Navon
2012 Stochastic environmental research and risk assessment (Print)  
A new parameter estimation algorithm based on ensemble Kalman filter (EnKF) is developed. The developed algorithm combined with the proposed problem parametrization offers an efficient parameter estimation method that converges using very small ensembles and without any tuning parameters. The inverse problem is formulated as a sequential data integration problem. Gaussian Process Regression (GRP) is used to integrate the prior knowledge (static data). The search space is further parameterized
more » ... ing Karhunen-Loève expansion to build a set of basis functions that spans the search space. Optimal weights of the reduced basis functions are estimated by an iterative regularized ensemble Kalman filter algorithm. The filter is converted to an optimization algorithm by using a pseudo time-stepping technique such that the model output matches the time dependent data. The EnKF Kalman gain matrix is regularized using truncated SVD to filter out noisy correlations. Numerical results show that the proposed algorithm is a promising approach for parameter estimation of subsurface flow models.
doi:10.1007/s00477-012-0613-x fatcat:xetaxtduyncqtlylax2koerkxe