Abstract: A method and apparatus for conveying a fluid flowing through a flow passageway (16) in a tubing (7), by; introducing into the flow passageway (16) flow zones of small cross-sectional area (11) alternating with flow zones of large cross-sectional area (12) to produce high-velocity, low-pressure zones alternating with low-velocity, high-pressure zones; and providing abrupt transitions from the small cross-sectional area zones (11) to the large cross-sectional area zones (12) to produce a turbulent flow generating swirls and eddies (19) at such transitions. The method and apparatus are particulary useful in oil well applications where the fluid is an oil-gas mixture, but could be used in other applications where the fluid is a liquid-sand mixture, a gas-liquid mist, or a viscous liquid.