Research Of Intelligent And Optimized Operation Technique For Large Scale Oilfield Injection System

Water injection is a very important exploitation mode in the oil field development. As it can effectively compensate formation energy, it has a positive effect on enhancing oil recovery efficiency and insuring high stable oil field production. But water injection itself consumes vast energy. Statistics indicate that water injection accounts for 33%-56% of the overall electricity consumption, and it will rise along with waterflood injection rate. Injection system operation scheme needs to be adjusted frequently to the change of injection rate in different phases. For many years, injection system operation depends on the experience of injection managers, which can't guarantee system working under optimized state, and produce low flood efficiency and high energy consumption. Thus, research on optimized operation technique of injection system will play a vital role on improving injection system operation efficiency, reducing energy consumption, realizing high efficiency, low consumption, ordered adjustment and scientific management. The following aspects are mainly researched in this thesis:Firstly, technological flow and pipe network configuration characteristics of oil field injection system are analyzed. Based on that, using hydromechanics theory and finite element method, the mathematical model that characterizes simulation of parameters (flux, pressure, etc) under injection system operation state is established. The model belongs to large-scale non-linearity system of equations. To improve reliability and solution efficiency, corresponding simplification strategy is advanced according to the configuration characteristics of injection pipe network, and iteration is adopted to solve the problem.Secondly, oil field injection system pump starting plan optimization is studied. With the minimum of injection energy consumption as the objective function, the hydraulic equilibrium, injection pressure as the constrained conditions, an optimization mathematic model of oil field injection system pump starting plan is established. The model is a large scale hybrid optimization design problem with disperse and continuous variables. In order to solve it effectively, according to the configuration and characteristics of it, a solution strategy for hybrid genetic simulated annealing algorithm, which combines GA,SA and separated optimization, is worked out.0-1 coding for chromosome, improved adaptive intercross and variation mode in operation, optimized reservation strategy are adopted. It has obtained a good effect in the practical application.Thirdly, injection system operation parameters optimization is researched when constant rate pump and VVVF pump are used together. The mathematical model is established, and solved with penalty function method. Based on that, with economic benefit and pay back period...