Droplet Size Distribution in Water-Crude Oil Emulsions by Low-Field NMR

Author(s)

Morgan, Vinicius G. ^[1] ; Sad, Cristina M. S. ^[1] ; Constantino, Andre E. ^[1] ; Azeredo, V, Rodrigo B. ; Lacerda Jr, Valdemar ; Castro, Eustaquio V. R. ^[2] ; Barbosa, Lucio L. ^[3]

Affiliation

^[1] Univ Fed Espirito Santo, Lab Pesquisa & Desenvolvimento Metodol Anal Petro, BR-29075910 Vitoria, ES - Brazil

^[2] Lacerda Jr, Jr., Valdemar, Univ Fed Espirito Santo, Lab Pesquisa & Desenvolvimento Metodol Anal Petro, BR-29075910 Vitoria, ES - Brazil

^[3] Univ Fed Sao Paulo Unifesp, Dept Engn Petroleo, BR-11030400 Santos, SP - Brazil

• Document type: Journal article
• Source: Journal of the Brazilian Chemical Society; v. 30, n. 8, p. 1587-1598, AUG 2019.
• Web of Science Citations: 0

Abstract

This paper reports the droplet size distribution (DSD) measurements in 28 W/O (water/oil) crude oil emulsions prepared with two Brazilian oils (medium and heavy) under different shear conditions using both 10 g L-1 NaCl solution and water production by low field nuclear magnetic resonance (NMR, 2.2 MHz). The PFGSTE (pulsed-field gradient-stimulated echo) pulse sequence applied was able to separate the crude oil emulsion signal for both medium and heavy oil even for low dispersed phase content (1.51 wt.%) and took into account only the aqueous phase signal. All emulsions exhibited an average diameter smaller than 5.5 µm because of the severe shear conditions. Despite the difficult processing of the S24 (6.48 wt.%) emulsion signal, good agreement was achieved between low field NMR and low-angle laser light scattering (LALLS) results. Finally, the paramagnetic ions in the water production did not affect the NMR measurements, demonstrating its applicability for analyzing real emulsions. (AU)

• FAPESP's process: 17/02856-0 - Development of Methodologies for Determine Brazilian Petroleum Properties and Onset Precipitation of Asphaltenes.
• Grantee: Lúcio Leonel Barbosa
• Support Opportunities: Regular Research Grants