Structure And Parameter Optimization Of Heavy Oil Heat Tracing Gathering Pipeline Network In Tahe Oilfield

A block reservoir in Tahe oilfield is a common heavy oil reservoir,which adopts the heat tracing gathering and transportation technology of single pipe and well head mixed with water,and the surface gathering and transportation mode is star shaped pipe network.In the surface construction,there are many new single wells and long distance between wells,which leads to high construction investment cost;in the production and operation,there are many problems,such as high water content,high heating temperature,high production energy consumption,high operation cost,etc.In order to reduce the cost of surface construction and production and operation,based on the process characteristics of a heavy oil block in Tahe oilfield,a new type of gathering and transportation pipe network,branch pipe network,was remodeled and designed in this paper.According to the structure characteristics of the pipe network,the optimization design of the structure and operation parameters of the gathering and transportation pipe network was carried out by using the optimization theoretical knowledge,which proved the research value of this kind of pipe network and obtained the best result Excellent pipeline parameters and operation parameters.The specific work is as follows:1.Before optimizing the branched oil gathering pipeline network,the temperature drop model of buried pipeline was established firstly.Based on the basic data of a heavy oil block in Tahe oilfield,the error analysis of the temperature drop model was carried out.The results show that the model is suitable for the heavy oil block.Then three typical pressure drop models,Dukler II model,Beggs-Brill model and Baker model,were selected.Based on the basic data of heavy oil block in Tahe oilfield,the error analysis of the above three models was carried out to determine that the Beggs-Brill model is more suitable for the heavy oil block,and the model is modified.Finally,according to the actual operation data of the block,the orthogonal test method was used to analyze the sensitivity of pipeline pressure drop.The results show that the primary and secondary order of influencing factors of pipeline pressure drop is: pipeline inlet temperature > pipeline inner diameter > liquid phase water content > crude oil viscosity.2.In this paper,the hierarchical optimization method was used to divide the optimization problem of the branch oil gathering pipeline network into two parts: the optimization of the structure layout of the pipeline network and the optimization of thepipeline and operation parameters.The appropriate optimization algorithm was selected to solve the problem.Firstly,the oil gathering process of branch oil gathering pipe network was determined.K-means algorithm was used to optimize the grouping of oil wells,and weighted average method was used to optimize the station location.Dijkstra algorithm was used to determine the distribution of branches in each well group,and the main pipeline of each branch was determined by fitting method.The single well under each branch was connected to the main pipeline by the shortest path,and the branch pipe network connection diagram was generated.Finally,the total length of branch pipe network,star pipe network and tree pipe network was compared,the results show that branch pipe network can significantly reduce investment.3.According to the determined branch pipe network structure layout,the optimization model was established with the minimum pipe network construction cost and operation cost as the objective function,and the corresponding constraints were formulated according to the national standards and actual production demand.The objective function was solved by the combination of penalty function method and particle swarm optimization algorithm,and the optimal pipeline parameters,operation parameters and related costs were obtained cost.