Effective removal of water and hydrocarbon liquids from gas wells can maintain and increase gas production. In this paper, results of flow loop tests on transport of liquid from casing to tubing is reported for flow rates ranging from 50% below to 50% above the critical gas flow rate for the tubing. The results show that liquid transport is severely constrained at the tubing-casing junction because the gas flow rate is usually much below the casing critical flow rate. To resolve the tubing-casing bottleneck, six approaches were tested: constrictions in the tubing, a vortex-generating device in the tubing, an assembly of baffles in the casing, a ball pack in the casing, a closed-end pipe in the casing, and foam-generating surfactants. The first two approaches provided no benefit. The last four approaches enhanced liquid lifting, in some cases by a factor of 10 or more. All approaches that increase liquid transport from the casing to the tubing also increase pressure gradient. Approaches that boost liquid transport rate with a small increase in pressure gradient are most desirable.

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