Since 1997 Vietsovpetro has been successfully applying the gaslift method of well operation on South Vietnam offshore fields, such as White Tiger, Dragon, White Bear, Beluga, White Hare. The gaslift method has a number of advantages providing the possibility to operate the wells with such complicating factors as high saturation pressure of oil, high gas-oil ratio, presence of asphaltene, resin and paraffin deposits and scaling, increased content and major solid returns during operation, significant well inclination angles. Gaslift downhole equipment allows running the tools for well testing, performing well stimulation by means of acidizing, repeated perforation, applying physical EOR methods. Conversion of wells into the injection system can be done without replacement of gaslift equipment and, therefore, without high costs on mobilizing the drilling unit. One of the major advantages among other artificial lifting methods is the long mean time between failures under the offshore fields conditions. However, the gaslift production method has some disadvantages. Operation of low-rate wells by the continuous gaslift method increases the specific gas flow rate, may lead to unstable lift operation, decreases the flow temperature at the wellhead and, therefore, increases paraffin formation on the tubings walls. There is a need to ensure the tightness of the downhole equipment and kick-off valves to secure well potential and reduce the specific flow rate of a compressed gas. Underperformance of gas lift operation can occur with the increase in water-cut of extracted products. Well operation depends on many factors that may vary over the period of development (water-cut, reservoir pressure, gas-oil ratio, pressure in the gathering and gaslift supply system). The experience of operating gas lift units in Vietnam fields showed that by eliminating multi-point gas injection and lift leaks, the specific gas consumption can be reduced by 20%, while ensuring the potential of well performance. Optimally distributing the compressed gas, it is possible to reduce specific costs by 10%. Therefore, one of the main objectives in monitoring the gaslift well stock operation is to research and identify the leakage areas in the downhole equipment and kick-off valves. Based on the tests results, the actions are developed to restore the equipment performance and improve its efficiency.
