Gas Lift System Efficiency Evaluation Method Research

Gas lift is a kind of artificial lifts that has very strong systematization. The gas-lift system is comprised of gas-lift pumping plant, gas distribution network, gas-lift well, and pipeline between gas-lift well and metering station. By research of calculating the method of efficiency of the above four parts, the corresponding mathematical model is established and verified by the test data from Wendong filed. Then the statistic analysis about the factor influencing of the efficiency of gas-lift system is made. Some measures are provided to improve the efficiency of gas-lift system. As a result, the energy of injection gas is saved; the efficiency is improved; the cost of oil production is cut down. Meanwhile this study also offers the theoretical base of optimizing gas-lift design and managing gas-lift well.In this paper, the main achievements in the aspect of efficiency of gas-lift system are as fllowing:1. The database is established to monitor the efficiency of gas-lift system.2. Mathematical model is established to compute the efficiency of gas-lift system that is centralized on gas-lift well. And the related mathematical models are established based on the research works about the efficiency of gas-lift pumping plant, gas distribution network, gas-lift well, pipeline (between gas-lift well and metering station).3. By combining the status of gas-lift well with economic benefit, the control chart of gas-lift well efficiency is presented, which supplies the technical support for the scientific management of gas-lift well.4. The software of testing the efficiency of gas-lift system is programmed in Visual Basic language. By anatomizing gas-lift system, the theorical base is given for gas-lift system optimism and management.Computation on the test data from Wendong field with the self-organized calculation software indicates that the proposed model performs well. The efficiency and energy consumption of the four parts are analyzed by statistics. What is more, the factors that affect the efficiency of gas-lift well are analyzed such as injection gas volume, injection gas/liquid ratio, injection pressure etc. Gas-lift wells in the Wendong filed are analyzed through the control chart of gas-lift well efficiency, and the typical gas-lift well of each distinct isscrutinized as well in detail. Therefore, some measures are proposed to improve the efficiency of gas-lift system.