Electrical Submersible Pump Control Based On Model Free Adaptive Control

The oil industry is the solid foundation for stability and prosperity in all aspects of life.All countries are putting a lot of resources into the development of the oil industry. With therapid development of modern science and technology, the oil industry is integration,automation and high efficiency. The oil exploitation is an important part in the petroleumindustry and also play a decisive role. Since the oil well downhole environment is verycomplex, the effect of temperature and pressure on the crude oil is big, therefore the processneeds to be controlled. The basic structure of submersible pump contains submersible motorand centrifugal pump. This thesis establishes and analyzes an double-loop control systembased on speed control and press control to improve system performance.The model free adaptive control is studied deeply. This method only uses input andoutput information from operating system to complete the control mission. On this basis, thecontroller mathematical models are structured and studied respectively with the three methodsof linear dynamic modeling. The setting method of control parameters is summarized by theexperiments. Based on the above work, three kinds of model free adaptive control schemes areapplied respectively in the control simulation experiments. The advantages and disadvantagesof three schemes are summarized by analyzing the experiment results.The working condition of electric submersible pump is in more than2kilometers depth.The motor temperature will change for the environmental and the motor itself factors.Temperature change leads to the change of resistivity of metal. It is the parameterperturbations for the model parameters change. In order to solve this problem, this thesis baseson the analysis of mechanical properties of the V/F control method and establishes thesubmersible motor model of variable voltage variable frequency control system. On this basis,the FFDL-MFAC method is applied to control the oil submersible motor for reducing theinfluence of temperature change. The feasibility and the superiority is verified by experiment.Electric submersible pump operates in the complex environment of high temperature andhigh pressure. The crude oil moves to the pump with the ground pressure. The bottom holeflowing pressure decreases in this process. If the bottom hole flowing pressure is lower thansaturation pressure of gas in the crude oil, it will lead to a large number of gas evolution and vaporization. It is very dangerous for electrical submersible pump. Controlling the oil pumpflow can maintain the downhole pressure balance of the environment. This thesis analyzes thedownhole pressure system and electric submersible pump and then establishes mathematicalmodel respectively. Considering the pressure feedback signal containing noise jamming signal,therefore, a filtering strategy is added to the original model free adaptive algorithm. Thefeasibility and the superiority is verified by experiment.