Modelling and Operation Optimization and Flow Control of Large Scale Water Injection Systems

This paper presents a new method for modelling and operation optimization of large scale water injection systems. Systems of tms Kma usually consist of a great number of water injection stations.pipelines.valves.pipe fittings,and water injection wells, and is a multi-source multi-sink nonlinear time-vaiying system with thousands of vanables. A properly simplified and sufficiently accurate mathematical model lias been made by both the analytical method and the system identification method. A new operation optimization method has been developed for this system by the large scale system theory and the dynamic programming method To solve this optimization problem.the concept of pressure valley in hydrodynamic system is presented for the first time in this paper. The water uniection system is divided into a senes of subsystems according to pressure valleys It has been proved 1 that system optimization on the whole is equivalent to optimization of every subsystem in it if coupling variables of the subsvstems have the values resulting from the optimized system. Thus, rhe system optimization problem is decomposed into a senes of subsystem optimization problems. The above modelling method and operation optimization procedures are programmed in a software package. This package has been applied to an oilfield in Daqing Electnc power consumption for water injection decreased by 3- 10%,and waterflood efficiency improved.