Abstract:
Tubings in injection and production wells of gas storage serve as dual channels in the process of gas injection and production. However, buckling behavior is prone to occur for the tubing in the complicated mechanical environment due to the large volume of gas injection and production, long operation time, forcible injection and production, and multi-cycle injection and production of gas storage, thus increasing the risk of tubing failure. Therefore, a theoretical model of tubing stress and deformation in gas storage under multi-cycle injection-production was established with reference to the operation characteristics of reservoir type gas storage, and the buckling behavior was judged and analyzed for the actual injection and production wells of a Gas Storage. The results show that: i) Buckling deformation may occur to the strings under the combined action of the internal and external pressure, temperature effect, swelling force and compressive force, with the maximum buckling ranging from sinusoidal buckling to spiral buckling; ii) Buckling does not occur to the tubing subjected to tension effect during gas injection, but actually occurs during gas production; iii) As the temperature distribution along the tubing has an important influence on the buckling behavior, the medium temperature can be increased appropriately during gas injection to reduce the axial load on top of the tubing, thus mitigating the risk of tubing failure. The research results are of great significance to the safe production of the injection and production wells in gas storage and the extension of the service life of tubings.