Theoretical research on sealing performance of packing element used in the dual gradient packer considering stress relaxation effect

• Published in: Journal of the Brazilian Society of Mechanical Sciences and Engineering 2022-06, Vol.44 (6), Article 237
• Main Authors: Zuo, Rundong, Wang, Guorong, Hu, Gang, Lei, Zhongqing, Shen, Kunrong
• Format: Article
• Language: English
• Subjects: Dimensional analysis; Engineering; Finite element method; Fluidizing; Mathematical analysis; Mathematical models; Mechanical Engineering; Packaging; Sealing; Stress relaxation; Structural design; Technical Paper
• ISSN: 1678-5878; 1806-3691
• DOI: 10.1007/s40430-022-03530-x

For the solid fluidization development process of deepwater hydrate based on the dual gradient of double-layer pipe, the sealing performance of the packing element of the packer determines the safety and the reliability of the entire system. Considering the stress relaxation effect, the working process of the packing element is divided into four stages, including the free deformation stage, the constrained deformation stage, the stress relaxation stage, and the sealing fluid stage. By describing the weakening of the sealing performance caused by the stress relaxation effect using the dimensional analysis method, the theoretical model on the sealing performance of the packing element used in the dual gradient packer is established. The corresponding finite element model considering the stress relaxation effect and multiple nonlinearities, whose results are close to those of the theoretical model, is developed as well. The research work can provide theoretical guidance for the structural design of the dual gradient packer.