Analysis Of Fluid-Structure Interaction Vibration Mechanism And Vibration Characteristics Of Gas Production Tubing String

During gas production,high-speed gas will generate unstable pressure pulsation waves,which will induce pipe string vibration.Pipe string vibration will in turn affect the movement characteristics of the fluid in the pipe string.The two interact and influence each other to produce fluid-structure interaction vibration.When the fluid-structure interaction vibration between the gas and the pipe string is severe,fatigue collapse or leakage of the pipe string may be induced.Therefore,in order to ensure the integrity of the pipe string during the gas production process,the fluid-structure interaction vibration mechanism and vibration characteristics of the gas production string are studied,including the following research contents:Considering the compressibility of natural gas,the influence of the vortex phenomenon caused by gas flow on the vibration of the pipe string is analyzed.The influence of the temperature field,pressure field and gas production and working conditions on the vibration of the gas string is investigated,and the gas pipe is clarified.Pipe string fluid-structure interaction vibration mechanism.Taking a vertical well as an example,considering the fluidstructure interaction between gas and pipe string,the axial and lateral vibration equations of the gas production pipe are established.The vibration equation is solved by the characteristic line method,numerical interpolation method and Galerkin method.The oil pipe is used as an example to quantitatively analyze the vibration characteristics of the pipe string.In addition,the ANSYS Workbench finite element software was used to analyze the modal analysis of the vertical pipe string 3D model,and the dynamics analysis of the pipe string with different curvatures of 30°,60° and 90° was carried out to analyze whether the fluid-structure interaction effect on the pipe string modality was considered.The effect of the gas inlet pressure on the pipe string vibration was examined.The research shows that the high-speed moving fluid will aggravate the vibration of the gas production string;the instantaneous change of the working condition will increase the axial vibration of the wellhead string;considering the fluid-structure interaction,the natural frequencies of the gas-collecting pipe string are reduced,and the resonance is more likely to occur;The bigger the curvature of the pipe string,the greater the variation of the pulsating pressure of the gas and liquid in the pipe string,the greater the impact force on the pipe string,the more severe the vibration of the pipe string;when the same inlet pressure,the displacement of the pipe string with different curvature is the largest.The fluid has a "straightening" effect on the pipe string.The research results can provide reference for the combination of pipe and pipe string,pipe selection and construction parameters.