Rheological study of W/O emulsion by low field NMR

Abstract The determination of the viscosity of oil emulsions is very important for the industry, because it is directly related to the performance in the process of recovery and refining. The behaviours of pseudoplastic fluids depend on the amount of emulsified water. In this study, 90 emulsions from ten crude oil with API degree ranging from 18.7 to 28.3 were investigated. The transverse relaxation time (T2) obtained by low field nuclear magnetic resonance (NMR) was used to determine the pseudoplasticity (n) and consistency index (k) of emulsions, containing percentage of disperse phase between 5 and 45% at distinct shear rate. From the experimental results, a model was proposed to calculate the k and n values from only one measure of T2. To validate the model, the emulsions of five different oils were used, yielding very satisfactory results for the NMR prediction of viscosity in the range of 100–600 mPa s. Finally, the fast measures and non-destructiveness sample make the low field NMR a good alternative to ASTM D2196-15 method, which is commonly used by oil industry to measure the dynamic viscosity.