Research On Scheduling Optimization Technology Of Multi-media Oilfield Sewage System

Sewage system is an important part of oilfield surface engineering.Its operation level determines the treatment effect of produced water,the quality of injected water and the rational utilization of water resources,which directly affects the economic benefits of oilfield development.At the same time,it also affects whether the whole oilfield meets the national environmental protection requirements.With China's onshore oilfields entering the tertiary oil recovery stage,the phenomenon of "gathering" of produced water under multi-development mode is more prominent,and the medium in sewage is multi-element.Raw water containing different media needs to be treated by different processes.The treated sewage will be treated to different depths according to the different water quality requirements of downstream injection.Therefore,the whole system has the characteristics of multi-media,multi-technology and complex pipeline network.In this case,the limitation of sewage dispatching based on manual experience is becoming more and more obvious.Especially for the rolling construction of large oil field stations,the complex connection of pipeline network,the unbalanced capacity of station and the outdated equipment all bring difficulties to the water diversion process.Therefore,it is of great theoretical significance and practical application value to carry out simulation optimization technology research of multi-media oilfield sewage system to achieve water balance and automatic allocation of different water quality in the system.In response to this problem,the following research work has been carried out:Firstly,the structure and process of multi-media oilfield sewage system are analyzed.On this basis,a mathematical model for calculating system node parameters is established.Drawing on the idea of "object-oriented" in computer language,the storage structure of sewage system data is designed.Based on binary tree data structure,a method for calculating node parameters of sewage pipe network system in multi-media oilfields is developed.The algorithm can calculate the parameters of pipeline flow rate,node flow rate,node pressure,load rate of sewage station,concentration of water in the inlet station,pump working condition and so on.It has the advantages of fast operation speed and low memory consumption.Secondly,considering the water diversion rules and water quality treatment requirements of multi-media oilfield sewage system,five kinds of constraints including total water quantity constraints,single station water quantity constraints,water quality constraints,load rate constraints of stations and reservoirs,pumping capacity constraints are constructed.The objective function is to minimize the total energy consumption in the process of diversion,and the water allocation among multi-level stations and yards is a decision variable.A mathematical model for optimal dispatching of oilfield sewage system with different transport media is established.In view of the complex characteristics of the model,an algorithm based on DFS(depth first search)is developed to find the water diversion paths between stations and reservoirs at all levels as design variables in the optimization process.The model is solved by combining particle swarm optimization with penalty function.Finally,combined with the theory of software engineering and C # programming language,the software of "Decision-making System for Assisted Dispatching of Sewage Pipeline Network in Multimedia Oilfield" is developed.The software is used to optimize the dispatching of multi-medium oilfield sewage in an oil production plant.The results show that the technology can effectively avoid the imbalance of water inflow and outflow,excessive concentration of aggregates and excessive load rate in the process of water diversion,and reduce the energy consumption of the system in the process of water diversion.