Data: 21/11/2024 (quinta-feira)
Horário: 11:00 h
Local: sala 201 da torre antiga
Caros estudantes e docentes,
O próximo seminário do grupo de matéria condensada ocorrerá com a apresentação do Prof. Ivan Oliveira (CBPF). O título e abstract seguem abaixo.
Tarik em nome da comissão organizadora.
*Teremos café e biscoitos antes 🙂
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Título:
Effects of geometrical complexity and the magnetic response of materials on the NMR observables in porous media
Resumo:
Observables in Nuclear Magnetic Resonance (NMR) experiments of fluids confined in porous spaces are primarily affected by the geometrical complexity and the magnetic response of the solid matrix and the fluid dynamics inside it. We report a numerical study of a porous system built from 50 random spheres containing brine in cylindrical solid matrix, which can be either quartz (low susceptibility contrast) or sediment (significant susceptibility contrast). By changing a single parameter, the geometrical complexity of the system can be modified. The internal magnetic field distributions in solid and fluid are determined. The results show that in the case of low contrast, a Carr-Purcell-Meiboom-Gill (CPMG) T2 experiment cannot distinguish the geometrical complexity of the pores, but if contrast is increased, it can. Moreover, we show that, in some cases, the CPMG value obtained for T2 in a low contrast experiment corresponds to the average value for the distribution of T2 calculated from the Brownstein–Tarr model, which is the standard model used to analyse NMR data in the oil industry.