Demulsification of Crude Oil Emulsions Tracked by Pulsed Field Gradient (PFG) Nuclear Magnetic Resonance (NMR). Part I: Chemical Demulsification

Abstract

Emulsified water droplets must be extracted from crude oil for economical and transport purposes, which is achievable by chemical demulsification. Four different chemicals were tested on water-incrude oil emulsions using a newly developed NMR method. Droplet size distributions were mapped at the beginning and end of experimentation. In addition, slice selections (soft RF pulses) were used to isolate the signal from residual droplets within the separated oil phase to study coalescence patterns in the emulsion bulk. The NMR could also return rapid continuous brine profiles for analysis of sedimentation rates and free water appearance kinetics. The residual water content was isolated by strong bi-polar gradient suppression, thereby allowing focus on the smaller droplets still emulsified in the top region in the brine profiles. Optimum concentrations were found for each chemical, and blends of several chemical demulsifiers were noticeably more efficient than the single component demulsifiers in this study.

Microfluidic Investigation of Crude Oil Droplet Coalescence: Effect of Oil/Water Composition and Droplet Aging

“…In petroleum research, most of the emulsion stability and coalescence studies are performed on oil-continuous systems [12][13][14][15][16][17][18][19][20] , whereas less data is available for produced water systems.…”

Trending approaches on demulsification of crude oil in the petroleum industry

“…A study was conducted to investigate the demulsification of crude oil emulsion traced by pulsed-field gradient (PFG) nuclear magnetic resonance (MNR) [24]. It was explained that the emulsified water droplet required for the transport and economical purposes was extracted from crude oil; this was achieved using chemical demulsification.…”

“…In the transport and processing of crude oil, the setback emanating from excessive water contents in the oil unfavourably reduces the purity of oil [54]. Moreover, increased contents of the waterin-oil is a challenging problem because the export quality standard needs water lesser than 0.5% [24].…”

Technologies Involved in the Demulsification of Crude Oil

“…The flocculation rate depends on a number of factors, such as the emulsion's water content, emulsion temperature, oil viscosity, the difference in oil/water density, and the electrostatic field. [10].…”