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 The normal gas-lift design leaves the tubing fully open.
This permits the use of BHP surveys, sand sounding and bailing,
production logging, cutting, paraffin, etc.
 High-formation GORs are very helpful for gas-lift systems
but hinder other artificial lift systems. Produced gas means less
injection gas is required; whereas, in all other pumping methods,
pumped gas reduces volumetric pumping efficiency drastically.
 Gas lift is flexible. A wide range of volumes and lift depths
can be achieved with essentially the same well equipment. In some
cases, switching to annular flow also can be easily accomplished to
handle exceedingly high volumes.
 A central gas-lift system easily can be used to service many
wells or operate an entire field. Centralization usually lowers total
capital cost and permits easier well control and testing.
 A gas-lift system is not obtrusive; it has a low profile. The
surface well equipment is the same as for flowing wells except for
injection-gas metering. The low profile is usually an advantage in
urban environments.
 Well subsurface equipment is relatively inexpensive.
Repair and maintenance expenses of subsurface equipment
normally are low. The equipment is easily pulled and repaired or
replaced. Also, major well workovers occur infrequently.
 Installation of gas lift is compatible with subsurface safety
valves and other surface equipment. The use of a surface-
controlled subsurface safety valve with a 1/4-in. control line
allows easy shut in of the well.
 Gas lift can still perform fairly well even when only poor
data are available when the design is made. This is fortunate
because the spacing design usually must be made before the well is
completed and tested.
Gas lift has the following disadvantages.
 Relatively high backpressure may seriously restrict
production in continuous gas lift. This problem becomes more
significant with increasing depths and declining static BHPs. Thus,
a 10,000-ft well with a static BHP of 1,000 psi and a PI of
1.0 bpd/psi would be difficult to lift with the standard continuous-

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