Recent developments in hydrocarbon separator interface imaging

Level monitoring instrumentation is an essential part of hydrocarbon processing facilities, and has together with separator technology been widely addressed over the last decade. Key issues are production capacity, product enhancement and well-flow control. The reliability and accuracy of the level instrumentation, and its ability to monitor the thickness of the foam and the oil-water emulsion, are particularly important when considering the level instrumentation as the main sensing element in the automatic control of the separation vessel. Lately industry focus has been placed on optimal automatic control to improve the quality of the production output, and to minimize the use of expensive and environmentally undesirable separation enhancing chemicals. Recent developments in hydrocarbon production includes subsea separation stations, where the constraints placed on the reliability and accuracy of the level instrumentation are especially severe. This paper discuss the most common existing level monitoring technologies, and present some recent level monitoring developments for three-phase separators. In order to clarify the issue of cross sectional metering the notion tomometry is introduced in this paper. Tomometry denotes multipoint cross sectional metering aiming to acquire cross sectional information on the distribution of the substances in the process vessel for control purposes, not mainly to create a cross sectional reconstructed image of the process in question.