Logan Smart
Enerview
Using gas to displace fluid and reduce hydrostatic pressure has been a producing practice since the late 19th century. As time has passed and technology has accelerated, we now are able to build a communication stream between gas lift optimization and the data acquired during production operations.
In our fast-paced industry, data is often looked upon to help us make decisions and solve problems from upstream to downstream. However, what is not talked about enough is how high frequency data allows us to see problems that should be factored into our decision-making process. Gas lift optimization levers are limited compared to ESP and rod pump systems. Rod pumping optimization can be done through the speed of the unit, also referred to as Strokes per Minute (SPM), stroke length and if the stroke length or current unit is at max capacity, then you can upgrade to a bigger unit. An ESP system’s biggest lever is going to be the wide operating speed range that could change production by over 1K BOPD of liquid. Both ESP and rod pumping systems can optimize through the VFD. ESP’s can chase pump intake pressure; pump discharge pressure and motor amps and rod pumps can chase pump fillage and load.
Gas Lift Optimization substitutes speed for injection rate but unlike ESP and rod pumping systems we can change our lifting depth along with the ability to produce from a deeper point in the well. With a constant change in lifting depth, we are constantly coming into conflict with understanding where we are lifting from and that is the first step in optimizing a gas lift well with multiple valves in the hole. ‘The great thing about gas lift is it works, the bad thing about gas lift is it works’, this quote I heard when I first started learning how to optimize gas lift wells still sticks with me. There have been hundreds of wells over the years that have had tubing leakage between stuck valves, holes in the tubing and mandrels, and leaking check valves. With the natural decline of an unconventional well merged with the start of a gas lift failure, it can be difficult to detect early.
By combining physics, gas lift knowledge and data analytics, we can have insight into where we are lifting these wells through a daily surveillance workflow. This is key to optimizing these wells and limiting our deferred production and the risk that goes along with matured failures.