Interface Layers Detection in Oil Field Tanks: A Critical Review

Abstract

An emulsion layer is a mixture of two or more liquids in which one of them the dispersed phase, is present as droplets of microscopic size, distributed throughout the other, called continuous phase. The existence of such layer between oil and water is due to the crude properties, and contaminants such as asphaltenes and resins. A measurement system to determine the boundaries of this emulsion in a modern oil production field is necessary to extract the pure single phase liquids [1, 2, 3]. This would for instance reduce the usage of expensive two phase flow meters and avoid the installation of additional tank separators along the upstream oil pipeline. In addition, this would help collecting accurate daily oil production statistics from each oil station. One widely deployed solution consists to inject chemical substances to completely eliminate the emulsion layer and leave only a crisp oilwater interface which can then be detected relatively much more easier. However, this approach is costly, not environmental friendly, and leads to a significant increase of the retention time in the separator. This book chapter provides a survey on electronic-basedtechniques which are capable to measure the high and low boundaries of the emulsion layer in real-time. It then describes in more details a new ultrasonic-based device along with the experimental results it could provide.