Research On Decision-making And Optimization Technology For Complex Oilfield Sewage System Adjustment And Transformation

Sewage system is one of the main systems to ensure the rolling production of oil field.With China’s onshore oil fields gradually entering the stage of tertiary oil recovery,under the multi-element and parallel development mode,the phenomenon of "gathering" of produced water from some oil wells is becoming increasingly prominent,and the composition of raw water is complex;the raw water containing different components needs to be treated by different treatment processes,that is,through various sewage stations with different functions.The treated sewage should be treated to different depths according to the different water quality requirements of downstream water injection.And then achieve the different requirements of water quality for subsequent reinjection of sewage.The dewatering station,sewage station and water injection station conduct sewage dispatching through sewage pipe network.It can be seen that the oilfield sewage system is a relatively complex fluid network with relatively complex structure connectivity.In the same operation cycle,there are many kinds of distribution networks of different levels and types coexisting,which makes the stations and reservoirs in different domains independent and restricted each other.Under special circumstances,such as the start and stop of pumps in the water injection station,the reconstruction of existing sewage station,the construction or shutdown of sewage station,how to transfer the water quality and quantity required by the water injection station in time with the optimal scheme to ensure the normal operation of the water injection system is an urgent practical problem to be solved in each major oilfield.At present,the operation management of oilfield sewage system and the decision-making of adjustment and transformation are based on the experience of field management personnel.The decision-making time is long,which can not guarantee the optimal scheduling decision-making.In view of the above problems,this paper takes the complex oilfield sewage system as the research object,and carries out the research on the decisionmaking optimization technology of the adjustment and transformation of oilfield sewage system.The main work is as follows:First of all,based on the analysis of the characteristics of the unique fluid network structure of oilfield sewage system,a mathematical model of hydraulic analysis and calculation of pipeline network is established,and the hydraulic calculation and analysis method of complex oilfield sewage system is formed based on the breadth first search(BFS)and the "graph theory".Combined with the effective ergodicity of the algorithm,the parameter calculation of sewage system node and pipeline unit is realized,with high efficiency.Secondly,based on the four common adjustment and transformation modes of complex oilfield sewage system,i.e.capacity building of sewage station,pump start and stop adjustment of water injection station,adjustment of existing station,shutdown and transformation of sewage station,the objective function is the lowest total scheduling cost of the system in the decision-making process,the decision variable is the scheduling water quantity between stations and reservoirs,the workload constraint is adjusted,and the operation characteristics of each seed mode are about Based on the constraints of bundle,flow balance,water quality and treatment capacity of stations and reservoirs,the optimal mathematical model of four adjustment and transformation modes of sewage system is constructed.According to the structural characteristics of the model,combined with the feasibility criteria and infeasible solution adjustment,the solution strategy of fireworks algorithm(FWA)is established.Finally,based on the theory of software engineering,using the object-oriented C# programming language,in the visual studio 2010 programming platform,the component GIS technology is embedded in the software,and the software system of "adjustment,transformation and scheduling decision-making of complex oilfield sewage system" is developed,which realizes the decision-making functions of hydraulic calculation analysis,adjustment,transformation and scheduling decision-making optimization of sewage system.The software is applied to optimize and analyze the decision-making problem of station and reservoir adjustment and reconstruction of a sewage system in a certain block.The results show that the technology can not only ensure the reasonable scheduling decision-making scheme,but also avoid the prominent contradictions of unbalanced production and injection,unbalanced load and unqualified treatment water quality of the sewage station.On the premise of reducing the operation and scheduling cost of the sewage system,it can effectively improve the decisionmaking efficiency and operation management level of the sewage system.