Analyzing and Troubleshooting Plunger-Lifted Wells

摘要

Development of a new portable monitoring system has takenrnthe guesswork out of plunger lift analysis, troubleshooting andrnoptimization. During one or more plunger lift cycles at highrnsampling speeds this system acquires data from the tubingrnacoustic signals plus pressure recordings from both the tubingrnand casing. The plunger generates an acoustic pulse as it fallsrnthrough each tubing collar recess when the well is shut-in.rnEach acoustic pulse travels through the gas in the tubing andrndetected at the surface. The pulses are converted to anrnelectrical signal by a microphone and pressure transducer.rnThe signals are digitized, stored and processed in a computerrnto determine plunger position, plunger fall velocity, andrnplunger arrival at the liquid level in the tubing. By analyzingrnthe collected data the operator can ensure that the plungerrnreaches the bottom of the tubing before the end of the shut-inrntime period. Setting the well's controller to have the shortestrnpossible shut-in time period can maximize oil and gasrnproduction from the plunger lift installation. Example datarncollected from various plunger lifted wells are presented inrnthis paper to show how to identify operational problems suchrnas holes in the tubing, stuck plungers and plungers not gettingrnto bottom.rnThe problem of not knowing the plunger location duringrnthe operation cycle has been overcome with this newrntechnology by allowing the operator to see the plungerrnlocation at any time during the cycle. Having a detailedrnanalysis of the operation of the well makes optimization ofrnplunger lift production achievable with a minimum of effortrnand avoids the usual waste of time due to trial and errorrnprocedures. Knowing the plunger's location is equallyrnimportant for timer-based as well as intelligent controllers,rnsince in both cases it is necessary to make initial estimates ofrnthe appropriate shut-in time, plunger arrival time and plungerrnfall time. The capability to calculate the volumes of liquid andrngas produced during the cycle and determining the well'srninflow performance gives valuable information to determinethe opportunity for increased production. Determining thernposition and velocity of the plunger throughout the cycle canrnaid in maximizing oil and gas production of a plunger liftrninstallation.