Chapter 3
results of sample 3 are similar to those of sample 1. On the top, water fraction is
zero, which corresponds to a clean oil layer. In the middle, water fraction is around
0.5, which corresponds to a water-in-oil emulsion layer. At the bottom, water
fraction is close to 1.0, which corresponds to concentrated water-in-oil emulsion
layer.
In the calculation of sample 4 (no solids, with PR5, Figure 3.21), T1 for bulk
water, oil, emulsified water and separated free water are 2.60 s, 0.63 s, 1.11 s and
2.32 s, respectively. Here T1 for emulsified water cannot be obtained from the
calibration of sample 4, because at initial time sample 4 is not homogeneous, due
to rapid coalescence. Thus here T1 value for emulsified water is assumed to be
that obtained from the calibration of sample 3. T1 for separated free water (2.10 s)
is also shorter than that of pure bulk water and is obtained from a separate NMR
measurement.
For sample 4, from water fraction profiles the separation of oil and water is
complete. On the top, water fraction is close to zero, which corresponds to clean
oil layer. At the bottom, water fraction is 1.0, which corresponds to free water.
3.6.5. Sedimentation rate from 1- D T1 MRI weighted profile measurement
In the profile results of samples 1 and 3, the step change of signal amplitude
is a response to the sedimentation front (boundary between different layers).
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