Characterizing water transport properties of partially saturated soils by joint inversion of NMR and IP measurements
Research Area:
Hydrogeophysics, Petrophysics, Soil Physics
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Figure 1: Modeling fluid flow in the pore space. Air (in blue) invades the water saturated sample from the right side.
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Figure 2: Water retention (pf) curve predicted by the joint inversion of NMR measurements at different water saturations in comparison to the measured water retention curve.
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Figure 3: The NMR slim-line logging tool developed by project A1 will be applied in the third project phase for characterizing the storage and flow properties of soils.
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Project B8, formerly resident in cluster A as project A2, aims at characterizing flow properties of partially water saturated soils by establishing direct relations between structural soil parameters (e.g. pore size distribution) and geophysical measurements , i.e. nuclear magnetic resonance (NMR) relaxometry, and induced polarization (IP). Since the third project phase will cover the upscaling and application of the methods in the field, project A2 moved to cluster B and will continue as project B8.
For establishing process formulations for describing water transport in the vadose zone, parameterizations are needed to replace the complex small-scale processes with macroscopic descriptions. The parameters usually have to be determined empirically, whereas in project B8 we characterize multiphase flow without empirical parameterization, but by stating direct relations between the parameters and the measurements.
The NMR slim-line logging tool, developed by project A1, will be applied to the field for characterizing storage and flow properties of soils. With the measured NMR and IP data, hydrological models will be parameterized, used for simulating water and gas flow in the vadose zone on a larger scale by other TR32 projects. For the estimation of flow properties, the existing tool will be supplemented by other measuring tools, i.e. a geoelectrical tool and tensiometers. Moreover, the developed joint inversion algorithm for NMR data and desaturation experiments will be extended to incorporate more complex pore space structures typical for real soils.
Cooperation partner:
Projects B4, B6, B7, D7
- E. Zimmermann, FZ Jülich
- A. Weller, TU Clausthal
- T. Günther, LIAG
- C. Rücker, TU Berlin
- O. Mohnke, Baker Hughes
