Measuring Fall Velocities of Various Plungers and the Resulting Optimization of Plunger

Using Trending to Troubleshoot and Optimize Plunger Lift

Tyrel Woodworth Brandon Baker Williams Production RMT

James F. Lea PLTech LLC

Abstract

Plunger lift is widely used to deliquify gas wells. The sole purpose of the plunger is to remove liquids from the wellbore which will restrict gas production. Plunger lift is popular because it is cheaper than other forms of lift, has low maintenance, uses limited downhole equipment, and very often does not require an external power source. It also functions in a variety of wellbore conditions.

Although it may be relatively simple to install plunger lift, analyzing the pressure and production trends of individual wells and their cycles can result in large increases in production. Not only can plunger cycles be optimized for maximum production, but surface and downhole failures can also be identified that keep the plunger from operating correctly. In addition to the cycle trending, simple calculations and rules of thumb may be applied to plunger settings to maximize efficiency.

There is much more to making plunger lift an optimal operation than just simply making sure the plunger travels up and down the wellbore every cycle. Off time and afterflow periods can be optimized. Build up pressures and instantaneous flow can be reviewed as an indication of liquid accumulation. Average casing pressure is an indication of formation producing pressure. Line pressure must be exceeded sufficiently to allow the plunger to lift liquids. Tubing and casing pressure trends can be analyzed to reveal surface and downhole failures or problems. There are also trends that help shed light on plunger condition.

These pressure and production trends will be discussed along with simple calculations using actual field SCADA system data and production curves. It will be shown how analyses of these trends were used to optimize and increase returns when using plunger lift to remove liquids from a gas well.