Research About The Application Of The Multiphase Interface Measurement System In Crude Oil Tank

With the continuous application of hydraulic fracture to improve oil recovery inoil production in China, the rate of water content of product oil is usually very high.In order to ensure the efficiency of oil production and oil storage, and the productionsafety of oil tanks, it is necessary to make highly accurate measurement of the crudeoil interface and the water interface. The accuracy of the existing tank multiphasemeasurement system is not high because of the mechanical part is easy to be coveredby the crude oil. Therefore, to develop a set of efficient, reliable and safe multiphasemeasurement system of the oil tank has an extremely vital significance to improve themetering accuracy and automation management level of the oil tanks.This paper first researches the development status of multiphase measurementmethods of oil tank in China and abroad. Then, based on the characteristics ofultrasonic propagation, a method to measure the multiphase of oil tank is presented.The method is to arrange two ultrasonic probes at the top and bottom of the tankrespectively to measure the height of the oil interface and the water interface. And thefeasibility of the scheme was demonstrated by an experiment. After that, the influencefactors on the measurement accuracy of the top and bottom of the oil tank areanalyzed. For the measurement of the oil interface, we propose to use the reflectingbaffle to compensate the velocity of the ultrasonic wave and use a horn resonator toimprove the directivity and radiation efficiency of the ultrasonic wave. For themeasurement of the oil, water interface, we analyzed the ultrasonic attenuation ofcrude oil and muddy water by experiments and made modification of the classicformula of the attenuation in crude oil, calculated the attenuation coefficient ofultrasonic in muddy water. The influence factors on the accuracy of the system arediscussed, and put forward methods to eliminate the crossover error and improve theecho signal-to-noise ratio.Finally, based on the theoretical analysis and experimental research on the above,the hardware and the system flow chart of the tank multiphase level measurement system are designed.