Application of the Ultrasonic Technique for Monitoring and Measuring thePhase Fractions of Liquid-Gas-Solid Mixtures

摘要

In many industrial applications, especially in the oil industry, the requirements of multiphase flow measurement posenumerous technological challenges as it oftentimes involve harsh media, strict safety regulations, access difficulties, longdistances, and aggressive surroundings. The fluids produced from oil wells most often emerge as a multiphase mixture of oil,natural gas, water, and a variety of solids (sand, hydrates, and asphaltenes). It is generally recognized that multiphase flowmetering (MFM), i.e. measuring the flow rates of the individual phases in a multiphase flow, could have many advantages interms of costs, layout of production facilities, well testing, reservoir management, subsea and downhole metering. In thisregard, the ultrasonic technique has been receiving increasing attention in the past years because it is noninvasive, fastresponding, and suitable for operation in harsh environments. In the present paper, initially a review is made of selectedcommercially available separation-type and in-line MFM systems; the multiphase flow parameters measured in each systemand the techniques used as well as general comments regarding the system performance are provided. Next, ultrasonicattenuation and transit time data are presented for oil-continuous oil-air-sand and oil-air-water mixtures in steel pipes. Adiscussion is also presented on attempts to sort out the air and sand concentrations in water-air-sand mixtures from ultrasonicsignals. It is hoped that the data presented will help establish the potential of the ultrasonic technique for use in MFM systemsin combination with or replacing specific instruments already in use.KUltrasonic technique;;multiphase flow metering;;oil-gas-sand and oil-gas-water mixtures