Analysis of tracer tomography using temporal moments of tracer breakthrough curves |
| |
| Authors: | Junfeng Zhu Xing Cai Tian-Chyi Jim Yeh |
| |
| Institution: | 1. Department of Hydrology and Water Resources, The University of Arizona, 1133 E James E Rogers Way, Tucson, AZ 85721, United States;2. Center for Biomedical Computing, Simula Research Laboratory and Department of Informatics, University of Oslo, Norway;3. Department of Resources Engineering, National Chen-Kung University, Taiwan, ROC |
| |
| Abstract: | Hydraulic/partitioning tracer tomography (HPTT) was recently developed by Yeh and Zhu Yeh T-CJ, Zhu J. Hydraulic/partitioning tracer tomography for characterization of dense nonaqueous phase liquid source zones, Water Resour Res 2007;43:W06435. doi:10.1029/2006WR004877.] for estimating spatial distribution of dense nonaqueous phase liquids (DNAPLs) in the subsurface. Since discrete tracer concentration data are directly utilized for the estimation of DNAPLs, this approach solves the hyperbolic convection–dispersion equation. Solution to the convection–dispersion equation however demands fine temporal and spatial discretization, resulting in high computational cost for an HPTT analysis. In this work, we use temporal moments of tracer breakthrough curves instead of discrete concentration data to estimate DNAPL distribution. This approach solves time independent partial differential equations of the temporal moments, and therefore avoids solving the convection–dispersion equation using a time marching scheme, resulting in a dramatic reduction of computational cost. To reduce numerical oscillations associated with convection dominated transport problems such as in inter-well tracer tests, the approach uses a finite element solver adopting the streamline upwind Petrov–Galerkin method to calculate moments and sensitivities. We test the temporal moment approach through numerical simulations. Comparing the computational costs between utilizing moments and discrete concentrations, we find that temporal moments significantly reduce the computation time. We also find that tracer moment data collected through a tomographic survey alone are able to yield reasonable estimates of hydraulic conductivity, as indicated by a correlation of 0.588 between estimated and true hydraulic conductivity fields in the synthetic case study. |
| |
| Keywords: | Temporal moments Source zone characterization Hydraulic/tracer tomography Parameter estimation |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
