Research On The Polymer Flooding Oil-gas Gathering And Transportation Low Temperature Gathering Technology

Low temperature gathering and transportation is a gathering and transportation process that can greatly reduce system energy consumption.Currently,the process is mainly used in oilfield water flooding systems.For polymer flooding systems and ternary flooding systems,due to the complex composition of oil well produced fluids and large changes in rheology,the technical limits of the low-temperature gathering and transportation process are still unclear and cannot be widely used.Aiming at the polymer flooding gathering and transportation system of an oil production plant in Daqing Oilfield,a low temperature gathering and transportation technology research was carried out.This research is of great significance for controlling energy consumption losses,reducing production costs,and improving oilfield economic benefits.According to the actual production situation of the oil production plant,comprehensively considering the physical properties of the produced fluid,polymer concentration and other factors,select water flooding oil transfer station,low polymer flooding oil transfer station,medium polymer flooding oil transfer station,high oil flooding oil transfer station For each one,the production and operation data collection plan was developed,and data collection was carried out,including related parameters of oil well fluid production,water cut,water mixing,produced fluid properties,starting and ending temperature and pressure of the gathering pipeline.The physical properties of the produced fluids in oil wells with different polymer concentrations are analyzed.The rheology is greatly affected by temperature,water content and polymer concentration,showing a non-Newtonian flow structure.Using the collected gathering pipeline production data,the heat transfer coefficients of different pipe diameters in different months were fitted,and the calculated error after fitting was less than 5%.Analyze and compare the accuracy of Baker model,B-B model and Dukler model for hydraulic calculation of polymer flooding oil-gas-water mixed pipeline,and modify the three calculation models by least square method and neural network learning method respectively.The results show that the Baker calculation model modified by the neural network learning method has the highest accuracy and the calculation error is less than 10%,which is suitable for the hydraulic calculation of the oil gathering pipeline of the oilfield polymer flooding system.The entropy weight method and gray correlation method were used to analyze the influencing factors of the technical limits of the low-temperature gathering and transportation technology of the polymer flooding oil and gas gathering and transportation system.A neural network method was used to establish the low-temperature gathering and transportation prediction model of the oil well in the polymer flooding system.The error between the prediction result and the actual production situation was about 5.2%,which was robust and able to guide on-site production.Aiming at the minimum production operation cost,taking the single well water mixing amount and the heating furnace outlet temperature as the control variables,and taking the safe gathering and transportation as the constraint conditions,the mathematical model of production operation parameter optimization of the polymer flooding gathering and transportation system is established,and the particle swarm solution is given algorithm.On this basis,the production management system(APMS)of polymer flooding low temperature gathering and transportation system was compiled through C #.The software includes hydraulic and thermal simulation,production operation optimization,calculation result query and other functional modules,which can realize the simulation calculation and optimized operation of the oilfield polymer flooding gathering and transportation network.The software was used to optimize the production and operation parameters of the gathering and transportation system of the four oil transfer stations.After the optimization,the daily production cost of the four oil transfer stations was reduced by 28% year-on-year,and the energy consumption was reduced by 21%.The annual energy consumption cost can be saved 8.43 million yuan,and energy saving and consumption reduction are significant.