Research On Fluid Accumulation Mechanism And Drainage Timing Of Multi-undulation Gathering And Transportation Pipelines In The Yanchang Gas Field

The Yanchang gas field is located in the Ordos Basin.The terrain is generally high in the west and low in the east.The terrain in the region is complex and has large fluctuations,resulting in large fluctuations and many fluctuations in the gas pipeline.To solve the trouble of liquid,starting from the essence of gas-liquid two-phase flow,understand the formation mechanism and distribution law of effusion,establish a mathematical model of liquid predict the location where effusion occurs for the first time,and provide reasonable drainage suggestions.In view of the above problems,on the basis of the field investigation of the Yanchang gas field,the application of software researches and analyzes the distribution law of liquid accumulation in the gathering and transportation pipelines in the Yanchang gas field.Use OLGA software to analyze the influence of pipeline inclination angle,outlet pressure,mass flow,and pipe diameter on the distribution of effusion,and use Fluent software to simulate the distribution of effusion in the undulating pipeline,understand the process of effusion formation,and provide the control of effusion in the pipeline.Guidance program.Since the calculation of liquid accumulation is related to flow type,liquid holdup rate,pressure drop,temperature drop,and other factors,in order to ensure the accuracy of the calculation results,this paper determines the appropriate gas-liquid two-phase flow type discriminant according to the actual situation of Yanchang Gas field.In this paper,the BWRS equation of state is used to calculate the physical parameters of the gas-phase fluid.Based on the Joule-Thomson coefficient calculated by the BWRS equation of state,the liquid holdup value is introduced to calculate the temperature drop of the undulated pipe.The mathematical model of liquid accumulation was established and programmed with Python language.the model is used to calculate the pressure drop and outlet temperature of the target pipeline,and compared with the steady-state calculation results of OLGA software,the absolute error of pressure drop and temperature of the mathematical model is 14.5% and 1.49%,and the absolute error of pressure drop and temperature of OLGA model is 2.42% and 2.42%,respectively.The data show that the model is more suitable for research on the liquid accumulation in the pipeline of the Yanchang gas field.The authors use this mathematical model to determine the first place where the effusion occurs by calculating the hydraulic ribs of the gas field.The results show that the first time the pipeline effusion occurs near the starting point 0 m of the Y285-BZ13 pipeline,the first time the pipeline effusion occurs near the starting point 350 m of the BZ1-BZ4 pipeline.Therefore,this paper is determined to be a discharge point to achieve the purpose of controlling the effusion.In terms of fluid prevention,the method of increasing the inlet mass flow or reducing wellhead pressure can be effective.In terms of liquid governance,this paper uses a minimum infiltration efficiency method,calculating the cleaning treatment when the outlet pressure is 5.97 MPa;this paper uses the maximum fluid amount to calculate the donor period of 104 days.