Nuclear Magnetic Resonance Analysis of Methane Hydrate Formation in Water-in-Oil Emulsions

Abstract

Water-in-oil emulsions are of particular interest concerning methane hydrate formation during crude oil production. The objective of this work is to understand the morphology of the hydrate/water drops in water-in-oil emulsions. Hydrogen nuclear magnetic resonance (NMR) is used to directly measure the formation of methane hydrates in water-in-oil emulsions. A 2 MHz NMR spectrometer is used to investigate the relationship between the drop size distributions of water-in-oil emulsions and methane hydrate formation. The drop size distributions of two crude oil and two model oil emulsions are measured by the pulsed-field gradient with diffusion editing technique. This technique is particularly useful because it does not assume a priori the functional form of the drop size distribution. The amount of liquid water converted to hydrate is directly measured by transverse relaxation measurements. These NMR techniques investigate the entire emulsion sample, and they provide useful information regarding the relationship between drop size distributions and methane hydrate formation in emulsified systems.