Effect of hydrate anti-agglomerants on water-in-crude oil emulsion stability

Autor: Azlinda Azizi, Michael L. Johns, Zachary M. Aman, Eric F. May, Nicholas N. A. Ling, Hazlina Husin
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: Journal of Petroleum Exploration and Production Technology, Vol 10, Iss 1, Pp 139-148 (2019)
Druh dokumentu: article
ISSN: 2190-0558
2190-0566
DOI: 10.1007/s13202-019-0691-0
Popis: Abstract Under high-pressure and low-temperature conditions, gas hydrate shells may form and grow at the interface of water droplets in water-in-oil emulsions. Such hydrate formation can enable downstream agglomeration and slurry viscosification, thus increasing the risk of hydrate blockage. Therefore, emulsion stability represents a critical parameter in understanding this overall flow behaviour. In this study, the impact of three common and widely-used industrial anti-agglomerants from three different suppliers (AA-1, AA-2 and AA-3—exact composition is commercially sensitive) on 30 wt% water-in-oil (W/O) emulsion stability was investigated. Bench-top nuclear magnetic resonance (NMR) pulsed field gradient (PFG) methods were used to measure the droplet size distributions (DSDs) of the W/O emulsions as a complement to bottle stability test. In the absence of hydrate anti-agglomerants, based on visual observation, 85% of the original W/O emulsion remained after 10 h. In the presence of AA-1 and AA-2, 94% of the original emulsion was retained; in contrast, AA-3 acted to destabilise the emulsion with only 64% of the original emulsion visually evident after 10 h. These results were substantiated by PFG NMR measurements which showed substantial changes in droplet size as a function of sample height for the W/O emulsion formulated with AA-3. Interestingly the W/O emulsion formulated with AA-1, while very stable, was characterised by comparatively very large water droplets, indicative of a complex multiple water-in-oil-in-water (W/O/W) emulsion microstructure. AA-2 forms stable emulsion with small droplets of water dispersed in the oil phase. Our results provide insight into a wide range of potential impacts of AA addition on an industrial crude oil pipeline, in which AA-1 resulted in a complex W/O/W multiple emulsion, AA-2 behaved as an emulsifier and AA-3 behaved as a demulsifier.
Databáze: Directory of Open Access Journals
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