Dynamic characteristics of production pipe strings for gas storage wells

Abstract During gas production at gas storage wells, the high-speed flow of gas results in the vibration of production pipe strings, thereby leading to changes in the mechanical properties of production pipe strings and their destruction. To study the dynamic characteristics of pipe strings in gas storage wells, a fluid–structure interaction analysis model for production pipe strings in gas storage was established by considering the interaction effect of gas and pipe strings in the lateral and longitudinal directions and solved by using the method of characteristic. The results of the proposed model were validated through a similar experiment and comparison with the simulation results of published studies. The field data of a gas storage well at the Huabei Oilfield were used as bases to discuss the effects of gas production rate, wellhead pressure, pipe string thickness, and gas density on the dynamic characteristics of pipe strings. Results show that pipe strings are subject to a large displacement at the well-opening moment, and then the pipe string vibration is gradually attenuated. A large lateral deformation occurs in the middle and lower part of the pipe string. Pipe string displacement and deformation increases with an increase in gas production rate and decrease with an increase in wellhead pressure and pipe string thickness. With the increases of gas density, the fluid–structure interaction between the string and the gas intensifies, resulting in the increase of the displacement caused by the string vibration. These findings are of significant importance in reducing the vibration of pipe strings and protecting them during gas storage well production.