Ultrasonic technique for tracking oil-water emulsion layer in separation vessels

• Published in: Journal of petroleum science & engineering 2020-01, Vol.184, p.106591, Article 106591
• Main Authors: Alshaafi, E.A., Prakash, A., Mercer, S.M.
• Format: Article
• Language: English
• Subjects: Acoustic velocity; Emulsion layer; Phase separation; Pulse attenuation; Ultrasonic techniques
• ISSN: 0920-4105; 1873-4715
• DOI: 10.1016/j.petrol.2019.106591

Ultrasonic based techniques have been explored to monitor emulsion layer and separation of oil and water phases from their emulsions. Creation of oil and water emulsions is a common occurrence in the petroleum and gas processing industry and several other commercial operations. This creates a multi-interface level measurement problem due to the presence of an emulsion layer in between oil and aqueous phase layers. The potential of ultrasonic-based methods has been tested by tracking the interphase position between the phases with suitably configured probes. The oil phase consisted of either crude or mineral oil while deionized water constituted the aqueous phase. The tests were conducted in a four inch diameter and twenty inch tall column mounted with acoustic probes. The measured acoustic parameters included, time of flight and energy content of the travelling wave at a selected frequency of 3.5 MHz. The ingress of emulsion phase layer at a sensor location could be easily detected since the probe design maintained a good signal-to-noise ratio even in highly attenuating emulsion phase. The observed attenuation losses in the emulsion phase are attributable to intrinsic losses and thermal effects. The simultaneous changes to acoustic velocity could be attributed to the fraction of water phase in the oil-water emulsions. •Potential of ultrasonic techniques to monitor emulsion layer in phase separation vessels has been demonstrated.•The selected probe configuration provided good signal to noise ratio all phases.•The fast response technique can be easily integrated into a control scheme.•The technique can also provide approximate estimates of water content in the emulsion phase.