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Title: Linearized Functional Minimization for Inverse Modeling

Heterogeneous aquifers typically consist of multiple lithofacies, whose spatial arrangement significantly affects flow and transport. The estimation of these lithofacies is complicated by the scarcity of data and by the lack of a clear correlation between identifiable geologic indicators and attributes. We introduce a new inverse-modeling approach to estimate both the spatial extent of hydrofacies and their properties from sparse measurements of hydraulic conductivity and hydraulic head. Our approach is to minimize a functional defined on the vectors of values of hydraulic conductivity and hydraulic head fields defined on regular grids at a user-determined resolution. This functional is constructed to (i) enforce the relationship between conductivity and heads provided by the groundwater flow equation, (ii) penalize deviations of the reconstructed fields from measurements where they are available, and (iii) penalize reconstructed fields that are not piece-wise smooth. We develop an iterative solver for this functional that exploits a local linearization of the mapping from conductivity to head. This approach provides a computationally efficient algorithm that rapidly converges to a solution. A series of numerical experiments demonstrates the robustness of our approach.
Authors:
 [1] ;  [2] ;  [3]
  1. Los Alamos National Laboratory
  2. University of California, San Diego
  3. Institute of Environmental Assessment and Water Research, Barcelona, Spain
Publication Date:
OSTI Identifier:
1044823
Report Number(s):
LA-UR-12-22406
TRN: US1203399
DOE Contract Number:
AC52-06NA25396
Resource Type:
Conference
Resource Relation:
Conference: International Conference on Water Resources (CMWR 2012) ; 2012-06-17 - 2012-06-17 ; Urbana-Champaign, Illinois, United States
Research Org:
Los Alamos National Laboratory (LANL)
Sponsoring Org:
DOE/LANL
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; 58 GEOSCIENCES; 97 MATHEMATICAL METHODS AND COMPUTING; ALGORITHMS; AQUIFERS; FUNCTIONALS; HYDRAULIC CONDUCTIVITY; HYDRAULICS; MINIMIZATION; RESOLUTION; SIMULATION; TRANSPORT; VECTORS; WATER RESOURCES