Gas-Well Liquid Loading Probed With Advanced Instrumentation

Abstract

Summary Drop size, liquid holdup, and pressure drop have been measured simultaneously in real time. This experiment was carried out with air/water to establish annular two-phase flow on a 0.019-m-internal-diameter vertical pipe (7-m-long multiphase-flow facility). Drop concentration, distribution, and sizes in the core flow were measured using Spraytec, a light-diffraction-based instrumentation. Liquid holdup was logged with pairs of flush-mounted ring-conductance probes at various positions within the test section. Pressure drop was monitored using a differential-pressure meter mounted between two pressure taps separated by a distance of 1.5 m. Subtle changes were observed in the characteristic drop diameters around gas superficial velocities of 21 and 30 m/s following progressive, systematic increase in gas and liquid superficial velocities. The gas superficial velocities at which these changes were observed have been linked with transition boundaries to cocurrent and mist annular flows, respectively. Corresponding similar pseudochanges, fingerprinted in the liquid-holdup and pressure-drop data at these transition boundaries, in addition to film and drop-flow reversals captured on video, make the evidence more compelling. Applicability of core-flow dynamic data to explain various physical processes associated with gas-well liquid loading has been demonstrated.