15 March 2017 – Seminar
When: 15:30 on Wednesday, 15th March 2017
Where: DIAS, Geophysics Section, 5 Merrion Square, Dublin 2, (library)
Speaker: Dr. Sean McKenna (IBM research in Dublin)
Title: Modeling Ground Water Flow and Transport in Strongly Heterogeneous Formations.
Transmissivity in heterogeneous and fractured media can range over many orders of magnitude. Predictive modeling within probabilistic risk assessment calculations requires numerical representations of these heterogeneous formations. Here, an example problem for a geologic repository is used to demonstrate the application of continuous and indicator geostatistics to create a set of seed fields conditioned to a complex geologic conceptual model and local measurements of transmissivity and storativity. Inverse parameter estimation with pilot points is used to modify these seed fields to condition them to observations of hydraulic pressure including the results of over 20 years of hydraulic testing. The resulting fields are used as input to an advective transport model. In order to quantify uncertainty in the transport predictions, multiple seed fields are run through the computationally expensive inverse calibration process. Several approaches to decreasing this computational load through decomposition of the parameters into a solution space and a null-space are examined and the impacts of each approach on the calibration and the advective travel time are quantified.