Modal Analysis and Strength Evaluation of the Downhole Axial Gas Compressor based on ANSYS Workbench

Abstract Downhole gas compression (DGC) is a new type of artificial lifting technology. DGC can reduce the gas inlet pressure and increase the gas outlet pressure by using the DGC system. It finally achieves the goal of increasing the production and recoverable reserves of the gas well, and improving the wellbore production effect. The DGC system contains three parts, the downhole axial gas compressor, the drive motor and the transmission mechanism. The downhole axial gas compressor is a key component to achieve gas compression, and it needs to be simulated and analysed during structure design. In this study, ANSYS Workbench was used to conduct modal analysis and strength evaluation on the rotor of designed downhole axial gas compressor. Firstly, the composition of the DGC system was introduced, the necessity of modal analysis and strength evaluation of downhole axial gas compressor was discussed. Then, the modal analysis and solving process were analysed theoretically, and the theoretical modal analysis results were obtained. Finally, ANSYS Workbench was used to analyse the modal analysis of the rotor as a whole of the downhole axial gas compressor, and the strength evaluation of a single rotor was conducted. The simulated results indicated that the designed downhole axial gas compressor would not resonate when the rotor was running at 34000r/min. The maximum stress of the rotor was 73.79MPa, which was smaller than its yield strength, and the structural strength of the rotor met the design requirements. The designed downhole axial gas compressor meets the working requirements.