Should you keep a Gas Lift back up on an ESP completion?
On a gas lift field, if you convert a well to ESP, should you keep a gas lift back up on it?
Gas lift backup is a typical debate in the company I work for. Being a gas lift guy, my answer will be “yes always keep a gas lift backup”.
Nevertheless this is not always a shared opinion. One of the argument that was recently given to me, for removing the gas lift mandrels was:
“if the ESP fails, then we can do a tubing punch with slick line, and restart with gas lift”.
To that I responded that intermediary valves are required to transfer the gas lift injection deeper in the well and hence achieve a much greater production rate.
Today I share another reason, why a tubing punch is not going to work as well as a gas lift valve.
Take a look at this interesting video:
Check the comparison of flow regime when changing the air injection head (1min 18s). Something similar will happen with a tubing punch compare to a gas lift valve.
So injecting through a tubing punch will make it less likely to produce with bubble flow regime, while this is the most favorable flow regime to maximize the production of your gas lift well.
That being said, bubble flow is rarely achieved in a well. This is because gas bubbles will coalesce as they move up. So along the tubing in a gas lift well, what you usually get is slug flow. Even though, injecting gas lift across a punched hole is likely to create instability in your well. This instability is caused by the unstable gas injection inherent to flow across a too large hole (that you will get if you do a tubing punch).
Gas lift through a punched hole in a tubing is not going to bring the expected results. Only do that if there are not other choices.
