Direct Method of Hydraulic Conductivity Structure Identification for Subsurface Transport Modeling

Abstract

AbstractSolute transport in aquifers is strongly influenced by the spatial distribution of subsurface hydraulic conductivity (K), while limited drilling typically results in lack of data characterizing both the K and the in situ fluid-flow boundary conditions (BC). To characterize such environments, this paper presents an efficient direct inverse method to simultaneously identify an aquifer’s K pattern, values, and flow field. The method ensures fluid-flow continuity using local approximate solutions of the governing flow equation conditioned to limited measurements, while the physics of flow are enforced, making the inverse problem well-posed. A single system of equations is assembled and solved, from which parameters and BC can be simultaneously estimated. For problems with irregular and regular K distributions, inversion is demonstrated for different measurement types, qualities, and quantities. When measurement error is increased, the estimated K pattern is largely insensitive to the error, although t...