The Research Of Simulation And Operating Optimization On Oilfield Water Injection System

Water injection is one of exploitation modes in oilfield development. Because of its vast energy consumption, the overall electricity consumption situation is becoming more and more severe and will increase rapidly along with the water-flood injection rate. To meet the requirements of water injection flow in different periods, the running scheme and operation parameters need to be changed frequently. Water injection system is a large scale, complicated and nonlinear network system. Therefore, to research the optimizing operation technology of water injection system is of great help for improving water injection system operation efficiency, reducing energy consumption, realizing high efficiency, low consumption and ordered adjustment. And it is of important significance on oilfield production.Based on fluid mechanics theory and finite element analysis method, the tube unit of water injection system is researched in this thesis. Meanwhile, according to the topology structure characteristics of water injection system network and hydraulic balance principle, a simulation model, which expresses the parameters'relationship in each running status of water injection system, is also established in this thesis, and the solving method is put forward along with the characteristics of this model.The hydraulic friction coefficient of oilfield water injection system has been changed owing to long time operation, aging and scaling. There is a big deviation between the results calculated by the traditional simulation model and measured values. To solve the problem, a correcting simulation model is established and solved by the Line-Up Competition Algorithm. Through the method that errors are transformed into equivalent tube lengths, the errors solving problem has been changed into optimizing problem, and the simulation model is corrected.Because the water injection system in optimized operation problem involves discrete variables (pump opening scheme) and continuous variables (pump flow rate), the optimized operation model of water injection system is established. By minimizing the total energy consumption of water injection system, the pump opening scheme and pump flow rate are considered to be optimized object, and the hydraulic balance, quantity of water injection and injection pressure are viewed as constraint conditions. This model is a large scale, complicated and mixed integer problem, and also solved by the Line-Up Competition Algorithm. Lastly, based on the above theory, the Simulation, Correcting and Optimizing models are realized by the computer, and the software of water injection system in scheduling optimization is developed through MATLAB language. The result of this software is close to actual production data. It can possess good guiding significance for water injection operation in oilfield.