Controle Fuzzy para otimização da produção de poços de petróleo equipados por Plunger Lift

Abstract

One common problem in gas wells is the excessive accumulation of liquids at the bottom of the well. This phenomenon often results in reduced production rates due to high values of flowing bottom hole pressure. The Plunger Lift represents a low-cost solution to this problem that uses a controller to calculate operating parameters. The development of a mathematical model for the Plunger Lift control is considered a difficult task, since it consists of a highly non-linear system with aspects of hybrid dynamics. Thus, the application of a fuzzy controller for this type of system represents a good alternative, since it does not require the use of a mathematical model, based on the experience of an expert. In addition, fuzzy can be designed to manipulate a secondary valve at the wellhead in order to increase the operational safety of the system. This work presents the application of a fuzzy controller to a Plunger Lift process for production optimization and regulation of the average piston ascent speed. The application results were compared with those of a conventional controller of the fixed time method. Production line disturbances and static pressures are present in the tests to approximate the application to a real system. An analysis of graphics and performance indexes was performed and the controller implemented successfully maintained optimal production rates. The gas and oil production of the fuzzy controller was approximately 55% higher than that of the fixed-time controller. The fuzzy controller reached safe operational values for the average rise speed of the plunger, about 4.5 m/s.