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Analysis of Formation of Water-In-Oil Emulsions

Clint P. Aichele1, Waylon House2, George J. Hirasaki1, Hariprasad J. Subramani3, Lee D. Rhyne3, and Walter G. Chapman4. (1) Chemical and Biomolecular Engineering, Rice University, 6100 Main St. (MS 362), Houston, TX 77005-1892, (2) Texas Tech, 2500 Broadway, Lubbock, TX 79409, (3) Flow Assurance, Chevron Energy Technology Company, 1600 Smith St., Rm. 30024B, Houston, TX 77002, (4) Chemical and Biomolecular Engineering Department, MS-362, Rice University, 6100 Main St., Houston, TX 77005

Water in oil emulsions have significant implications during crude oil production. Specifically, the drop size distribution (DSD) of the emulsion, and the mechanisms of emulsion formation provide key insights when formulating effective strategies for crude oil production. In this work, the water is emulsified in model or crude oils in a Taylor-Couette shear cell. Nuclear Magnetic Resonance (NMR) is utilized to determine DSD and the one dimensional spatial distribution of the components (viz., water and oil) in the emulsion. NMR is particularly useful because it is not constrained by the optical properties of the crude oil emulsions and it can investigate the entire emulsion sample and not a localized region of the sample. The DSD measurements are performed using the pulsed field gradient with diffusion editing (PFG-DE) technique, which does not assume the functional form of the DSD. The effect of the imposed shear field and shear history on the DSD of emulsions is studied (a) experimentally by subjecting the water-model oil and water-crude oil systems to a wide range of rotational speeds and residence times of the sample in the Taylor-Couette cell and (b) computationally via numerical simulations in FLUENT. Such quantitative information on the mechanism of formation of water in crude oil emulsions is invaluable because conventional optical measurement techniques fail when employed to investigate water in crude oil emulsions.