Xiaolan Luo

Metal sealing performance of subsea X-tree wellhead connector sealer

The metal sealing performance of subsea X-tree wellhead connectors is crucial for the safety and reliability of subsea X-trees. In order to establish the theoretical relation between metal sealing ring’s contact stress and its structural parameters and working pressure, a mechanical analysis method for double-cone sealing of high pressure vessels is applied in analyzing the metal sealing ring under the condition of preload and operation. As a result, the formula of the unit sealing load for the metal sealing ring under operation with residual preload is shown in this paper, which ensures that the metal sealing ring has an excellent sealing effect and can prevent the metal sealing ring from yielding. Besides, while analyzing the sealing process of the metal sealing ring, the change rule of contact stress and working pressure is concluded here, putting forward that the structural parameters of the metal sealing ring are the major factors affecting the change rule. Finally, the analytical solution through theoretical analysis is compared with the simulation result through finite element analysis in a force feedback experiment, and both are consistent with each other, which fully verifies for the design and calculation theory on metal sealing ring’s contact stress and its structural parameters and working pressure deduced in this paper. The proposed research will be treated as an applicable theory guiding the design of metal seal for subsea X-tree wellhead connectors.

Thermal Stress Calculation and Its Application to Bending Angle Design of Flowlines of Subsea Christmas Tree

Based on diverse situations of the flowline of subsea Christmas tree installation and its working conditions, a theoretical model for calculation of the flowline is proposed by taking comprehensive considerations of different influencing factors, such as water depth, temperature of petroleum and gasoline, and angles of the flowline. By using the ABAQUS software, a finite element model for the flowline operating in an oil field in South China Sea is developed for verification of the proposed theory. The analysis and calculation present the variation of the thermal stress with different water depth, different oil & gas temperature and different bending angle of the flowline, and provid a theoretical support for the appropriate bending angle design of the flowline in the specific fields.

Buckling of Flowlines of subsea Christmas tree Based on Genetic Algorithm

By using the ABAQUS software, a finite element model for the flowline operating in South China Sea is developed and the structural strength analysis of the flowline under different water depth is performed. Meanwhile, by using genetic algorithm, the variation trend is forecasted, which is based on the calculation results of the flowline under different water depth, and the reason why the flowline of subsea Christmas tree occur buckling under the external pressure is analyzed. Through calculation and analysis, the variable rule of the structural strength of the flowline under different water depth is summed up, and suggestions for the design of the flowline of subsea Christmas tree are provided.