NMR IMAGING OF MULTIPHASE FLOW IN POROUS-MEDIA

Nuclear magnetic resonance (NMR) imaging techniques are used to determine porosity and saturation distributions. Difficulties in quantitation which arise from the short transverse relaxation times exhibited by fluids in porous media are addressed. Procedures are presented whereby transverse relaxation during the signal acquisition process is modeled to obtain accurate estimates of intrinsic magnetization intensity, and thus porosity and saturation. Special consideration is given to saturation/position dependence and multiexponential behavior of transverse relaxation. These procedures are validated with results for longitudinal profile images. The use of thin-slice cross-sectional profile images are demonstrated by observing fluid displacement in a rock sample with structural heterogeneities.