Use of four-dimensional ground penetrating radar and advanced visualization methods to determine subsurface fluid migration

Four-dimensional (4D) or time-lapse three-dimensional (3D) ground penetrati ng radar surveys can be used to monitor and image subsurface fluid flow. Th is information can be used to create a model of hydrogeological properties. The massive amount of data, which is present in and can possibly be genera ted from 4D GPR data sets, precludes a manual interpretation. Consequently, 4D data sets have to be processed and visualized in a way that extracts mo dels and allows for data visualization in a semi-automatic way. The princip les behind such an approach are applied to the Borden data set, which is us ed to demonstrate how advanced visualization can assist in the interpretati on of raw and processed data. In the Borden data set, changes in reflectivi ty between different time-steps unveil areas of fluid migration in three di mensions. The combination of these reflectivity changes (between different combinations of the 3D subsets of the 4D data set) is used to create a mode l of hydrogeological properties. While this model does not yield a quantita tive description of porosity, permeability or hydraulic conductivity, it is a qualitative proxy for a combination of these properties. (C) 2000 Elsevi er Science B.V. All rights reserved.