A cellular automata‐based deterministic inversion algorithm for the characterization of linear structural heterogeneities. Issue 3 (11th March 2017) - Fischer, P.
Abstract: Inverse problem permits to map the subsurface properties from a few observed data. The inverse problem can be physically constrained by a priori information on the property distribution in order to limit the nonuniqueness of the solution. The geostatistical information is often chosen as a priori information; however, when the field properties present a spatial locally distributed high variability, the geostatistical approach becomes inefficient. Therefore, we propose a new method adapted for fields presenting linear structures (such as a fractured field). The Cellular Automata‐based Deterministic Inversion (CADI) method is, as far as we know when this paper is produced, the first inversion method which permits a deterministic inversion based on a Bayesian approach and using a dynamic optimization to generate different linear structures iteratively. The model is partitioned in cellular automaton subspaces, each one controlling a different zone of the model. A cellular automata subspace structures the properties of the model in two units ("structure" and "background") and control their dispensing direction and their values. The partitioning of the model in subspaces permits to monitor a large‐scale structural model with only a few pilot‐parameters and to generate linear structures with local direction changes. Thereby, the algorithm can easily handle with large‐scale structures, and a sensitivity analysis is possible on these structural pilot‐parameters, which permits to considerably accelerate the optimization process in order to find the best structural geometry. The algorithm has been successfully tested on simple, to more complex, theoretical models with different inversion techniques by using seismic and hydraulic data. Key Points: A novel inverse approach is developed to reconstruct the structural heterogeneities The cellular automaton method is used to parameterize the inverse problem The inverse algorithm is validated on the hydrogeological and geophysical data