STRUCTURAL STRENGTH ANALYSIS OF FLEXIBLE FLOWLINE CONNECTOR UNDER MULTI-LOAD IN DEEPWATER

In the complex and special environment of deepwater, the subsea flexible flowline connectors are affected by various load conditions, which will affect the safe operation of subsea pipelines and the reliability of the entire subsea production system, thus put forward higher requirements for the structural safety performance of the connectors. Based on this, taking the deepwater installation project of gooseneck connector for flexible flowline in a gas field in South China Sea as an example, the working principle and basic parameters of gooseneck connector are introduced, and the advantages of gooseneck connector compared with traditional vertical connector are analyzed. Using design of experiments (DOE) optimization technology, the ultimate load calculation of gooseneck connector in three deepwater working conditions, i.e., flexible flowline laying stage, connector subsea leak test and hydrostatic pressure test, was studied. On this basis, finite element simulation calculation analysis and strength check were carried out. The results show that the complete load condition inspection of the gooseneck connector is carried out under various load combinations, and all the loads applied to the flange under each working condition meet the requirements. Under each working condition, the overall stress of the gooseneck connector is less than the allowable stress, and the overall strength of the overall structure is sufficient to meet the safety requirements. The maximum stress in each working condition is concentrated at the 90° elbow, and its strength is checked to meet the requirements of the American Society of Mechanical Engineers (ASME) standard. The analysis results in this paper can provide theoretical basis and technical reference for the structural optimization design and deepwater installation of subsea flexible flowline connectors.