The Study On Optimal Operation Of Oilfield Water Injection System

At present,the operation of oilfield water injection system implementation mainly depends on operators’ experience.But it can’t guarantee optimal operation for such a large complex system,which may result in the problem that displacement of pump does not match the quantity of water.Besides,the efficiency and consumption of water injection system would deviate from the normal level without timely adjustment.Therefore,the operational optimization of water injection system is urgent for engineers.By investigating the technological flow and pipe network configuration of oilfield water injection system,the article has set up a simulation model that includes water injection stations,water-distributing rooms,wells,pumps and other units.Based on the energy and mass conservation equations,the formulas concerning the flowrate and pressure of pipe network are given.Finally,the pipe network solution matrix of water injection system is established for the improved nodal equation algorithm.By setting the boundary conditions,the Newton-Raphson method is used to solve the unknown parameters.Based on the hydraulic parameters of the pipe network,the indexes of power consumption are calculated,which are integrated by fuzzy comprehensive evaluation model for evaluating the operating status of water injection system from overall operation state.Based on the topological structure of pipeline network,the model takes the minimum of power consumption of water injection system and water deviation of well as the objective function,the binary variable is introduced to characterize the operation state of pump.In addition,it takes into account the pressure of well,as well as the operating capacity of equipment and other hydraulic constraints to set up optimization model.Then,by means of flow library that can linear the nonlinear model,the global optimal solution of the optimization model is obtained by branch and bound method.The operational optimization software of water injection system can provide reference for formulating energy-saving plan that was designed by Python language,which can achieve functions that covering hydraulic simulation and operational scheme optimization.Based on the current situation of water injection system in Daqing oilfield,the operational state of the water injection system was simulated by the developed operation optimization software,and the accuracy of the pipe network model was verified.On this basis,the energy consumption of the system is reduced and the water injection effect is improved after optimizing pumping plan which is compared with the actual operation scheme.