Top 3 Gas Lift well issues
There are 3 very common issues with gas lift wells:
1) Gas Lift injection is happening across a shallow valve (figure 1), instead of across the orifice set in a deeper mandrel.
2) Gas Lift injection is happening across several valves at the same time aka multipointing (figure 2).
Both cases are symptomatic of a Gas Lift design that is not adapted to the field operating conditions; therefore, the well is not able to complete its unloading sequence. As a result, it won’t produce as much as if all the Gas Lift was injected across the desired deeper injection point. Yet the well often still produces and gets unnoticed.
3) Gas lift is injected across the orifice, but lower mandrels equipped with dummy valves exist in the well and could be used for Gas Lift injection (figure 3).
In a properly designed Gas Lift completion, spare mandrels are installed deeper than the initial Gas Lift injection point. They are initially equipped with dummy valves (acting as plugs in the mandrel). With changes in well conditions (for instance due to reservoir depletion), these dummy valves can be removed and replaced by Gas Lift valves to lower the injection point.
In this case, again, the well doesn’t produce at its full potential. But the fact that it still produces in most cases will make it harder to detect.
High potential for Gas Lift production optimization
All 3 cases show high potential for low investment and quick payback production optimization operations. Indeed, replacing the Gas Lift design to achieve well optimization is a rather simple and light operation. It involves a slick line unit to run appropriate tools in the well to recover the old valves and install new ones. This is a cheap and fast well intervention operation. It, therefore, allows optimization of most Gas Lift wells, even those with production rates below 50 bopd in an offshore environment.
