Plunger lift is the primary lift type for de-liquefying gas wells. It is a great fit for lower producing gas wells because of relatively low capital investment, maintenance costs, and energy requirements, compared to other artificial lift methods. Plunger lift is highly energy efficient because it uses the well’s reservoir energy as well as energy from gas pressure in the annulus. Intervention costs are also significantly lower than other forms of artificial lift because new plungers can simply be dropped from the surface, and the entire system can be repaired or replaced with slickline if necessary. More recently, plungers have been implemented in horizontal shale wells to help extend the flowing period and prevent liquid loading as well as the late-life form of artificial lift. Plungers can also be used in conjunction with gas lift, called Gas assisted plunger lift (GAPL), where compression is available.
The main components of a plunger lift system include:
• The plunger, which is a metal piston that creates a pressure tight seal against the tubing wall and transports accumulated liquids above it to surface
during its trips
• The bumper spring, which the plunger rests on while on bottom. The bumper spring can be installed on a tubing collar-stop or inside of a profile nipple and some may come with standing valves to prevent accumulated liquids from exiting the end-of-tubing.
• Lubricators, which catch and hold the plunger at the surface. They are generally equipped with a spring-loaded arrival dampener, arrival sensor, and catcher.
• A motor valve, which opens and closes based on a signal from the plunger controller to regulate the open and shut-in portions of the plunger cycle.
• A plunger controller, which provides logic to determine when to open and close the well for flow. There are many vintages of plunger controllers with varying degrees of sophistication and control capabilities.
Multi-stage and multi-pad horizontal wells have created a new market for plunger lift in recent years. The steep decline curves and harsh well conditions have made plunger lift attractive as a transitional lift type, and gas-assisted plunger lift (GAPL) has become a prevalent late life lift form in higher GLR shale plays. These highly instrumented shale wells still face many of the same challenges as low producing gas wells - highly manual, time intensive optimization workflows, which are difficult to scale as well count grows.
Some key challenges are:
• Manual workflows: Plunger wells require constant tracking of well parameters (run times, missed trips, open time, gas flow rate) in order to keep the well optimized and prevent liquid-loading. Well counts for engineers and technicians keep climbing, but workflows and optimization capabilities have not kept up - meaning that the lowest producing wells often don’t get the attention they need to produce optimally.
• Improving up-time: Without automated optimization capabilities, many operators lean on the cautious side and leave the well shut in for longer time periods to prevent liquid loading, thus leaving production on the table.
• Lack of anomaly detection: Unlike rod pump and other forms of artificial lift, many plunger lift problems are due to “soft failures”, wherein the well will continue to produce at just under optimal levels, so failure detection can take significantly more time and investigative work to diagnose.
• Worn plungers go unnoticed: Because most plunger controllers don’t have smart alarms to alert operators when plungers wear, the well continues to produce less and less efficiently until the problem is detected manually by the operator or engineer. Ambyint can diagnose and alert users in real-time when worn plungers are causing a loss of efficiency, and decrease the time to resolution.
• Missed trips lead well to load up: Without smart alarms, users are unable to determine if a well is slowly loading up unless they manually track plunger arrival times over time. Even if a controller is setup to alert when a trip is missed, manual intervention is still required determine what parameters need to be manipulated. Ambyint observes every trip and sends alerts when an anomaly occurs. Ambyint can also automatically make changes based on observations from past trips, saving hours of trending to find the root cause and enabling field teams to keep their entire field continually optimized.
The term “long stroke pumping unit” typically refers to units such as Rotaflex, hydraulic pumping units, and other pumping units that operate with pure up and down stroke cycles, versus conventional rotary cycles. As the name states, the primary goal of these units is to achieve a longer stroke length and maximum pump displacement at a much lower SPM. An additional benefit sometimes sought by operators is the reduced footprint offered by some hydraulic pumping unit manufacturers. Ambyint integrates with all major long stroke pumping units to provide adaptive control and remote visibility.
Due to the marginal economics and remote nature of many plunger-lifted wells, investments in wellsite communication and automation have been hard to justify. Even when automation is available, keeping plunger runs optimized demands constant manual intervention. Ambyint’s end-to-end platform was built with the economics of low-value wells in mind. Our platform overcomes the economic and technological barriers posed by conventional automation solutions to provide real time control and visibility of plunger lift wells.