1. n. [Well Completions]

The commingled flow of different phase fluids, such as water, oil and gas. Multiphase fluid flow is a complex factor, important in understanding and optimizing production hydraulics in both oil and gas wells. Four multiphase fluid flow regimes are recognized when describing flow in oil and gas wells, bubble flow, slug flow, transition flow and mist flow.

See: bubble flow,  mist flow,  slug flow,  transition flow