Chapter 3
and oilfield emulsions[10]. This application is an extension of the usage of NMR
relaxation measurements for the determination of porosity in minerals and rocks.
If the fluid is confined in a planar, cylindrical or spherical cavity, the relaxation
can be written as [11]:
1 1 Z5X ro e1
-^=r--+ pU' [3'5]
12,i 12,bulk K
Here p is surface relaxivity. For the same water∕oil system, p keeps constant.
(S∕V)i is the surface to volume ratio of cavity /. For a sphere of radius ai, Eq. [3.4]
becomes:
113 11
- = ~ + P~, αi=3p∕(-~-) [3.6]
12,i 12,bulk ai 12,i 12,bulk
The number of protons present in a given volume of sample determines the
signal amplitude. For this reason, the fraction fi that is associated to each T2,∣
value renders a direct measurement of the fraction of droplets with the radius a∣.
Drop size distribution of emulsions can be obtained from T2 distribution. The
requirements for Eq. [3.5] are [5]:
1) Measurements are performed in the “fast diffusion” mode, that the
characteristic time scale tD for molecule diffusion should be much smaller
than that of surface relaxation t0. — = a∖lD « 1, => « 1. D is
p tp a] ID D
diffusivity of dispersed phase.
41
More intriguing information
1. On the Existence of the Moments of the Asymptotic Trace Statistic2. The Integration Order of Vector Autoregressive Processes
3. The name is absent
4. Managing Human Resources in Higher Education: The Implications of a Diversifying Workforce
5. The name is absent
6. The Economics of Uncovered Interest Parity Condition for Emerging Markets: A Survey
7. Restricted Export Flexibility and Risk Management with Options and Futures
8. Om Økonomi, matematik og videnskabelighed - et bud på provokation
9. Electricity output in Spain: Economic analysis of the activity after liberalization
10. Une nouvelle vision de l'économie (The knowledge society: a new approach of the economy)