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highlighted in the following discussion. If plunger lift can be used
instead of only intermittent lift, the efficiency will be higher. This
difference could determine the success or failure of the system.
Intermittent gas lift has the following advantages.
 Intermittent gas lift typically has a significantly lower
producing BHP than continuous gas-lift methods.
 It has the ability to handle low volumes of fluid with
relatively low production BHPs.
Intermittent gas lift has the following disadvantages.
 Intermittent gas lift is limited to low volume wells. For
example, an 8,000-ft well with 2-in. nominal tubing can seldom be
produced at rates of more than 200 B/D with an average producing
pressure much below 250 psig.
 The average producing pressure of a conventional
intermittent lift system is still relatively high when compared with
rod pumping; however, the producing BHP can be reduced by use
of chambers. Chambers are particularly suited to high PI, low BHP
wells.
 The power efficiency is low. Typically, more gas is used
per barrel of produced fluid than with constant flow gas lift. Also,
the fallback of a fraction of liquid slugs being lifted by gas flow
increases with depth and water cut, making the lift system even
more inefficient. However, liquid fallback can be reduced by the
use of plungers, where applicable.
 Fluctuations in rate and BHP can be detrimental to wells
with sand control. The produced sand may plug the tubing or
standing valve. Also, pressure fluctuations in surface facilities
cause gas- and fluid-handling problems.
 Intermittent gas lift typically requires frequent adjustments.
The lease operator must alter the injection rate and time period
routinely to increase the production and keep the lift gas
requirement relatively low.

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