A Stress Joint Based on Top Tensioning Riser and Its Optimal Design Method

Abstract

The invention relates to a stress adapter based on a top tension-type vertical tube and an optimum design method thereof. The invention is characterized in that the stress adapter is tapered, the inside diameter of the stress adapter is constant, the outside diameter of the stress adapter is gradually increased from top to bottom, the wall thickness of the stress adapter is gradually increased, the top of the stress adapter is connected with the vertical tube, the bottom end of the stress adapter is connected with an underwater head system. The optimum design method comprises the following steps of: (1) acquiring basal data of the vertical tube and calculating a top outside diameter and a constant inside diameter of the stress adapter; (2) selecting a design parameter (alpha j); (3) determining a bottom outside diameter (Phi eL) according to the following formula: alpha j=RjL/Ri0= PhieL/Phie0; (4) determining a length (Lj) of the stress adapter according to the following formula: Lj=Rj0 Theta j(alphaj-1)/ln(alpha j); (5) determining a cross-sectional outside diameter (Phi ex) according to the following formula: Pie x=Phie0alphax; and (6) designing the stress adapter based on the results of the above steps, then checking performances of the stress adapter, and returning to the step (2) if the check results are not meet the performance requirements.

Description

technical field [0001] The invention relates to a stress joint and an optimal design method thereof, in particular to a stress joint based on a top-tensioned riser and an optimal design method thereof. Background technique [0002] With the great increase of deepwater development activities, the technical equipment of deepwater development is also constantly facing new challenges, and different requirements are put forward for the riser system connecting the submarine pipeline and the platform. Deepwater risers are flexible structures that are often directly connected to rigid structures. When both ends of the riser are fixedly connected to the rigid structure, especially the production riser is directly connected to the seabed or directly to floating structures, platforms, etc. When the connection is fixed, its flexibility will sharply decrease or even disappear. The bending strength of such a connection is very important in the local response. Therefore, when designing a d...

AI Technical Summary

Problems solved by technology

At present, the design of stress joints is mostly based on the relevant experience of the designer, and the stress joints are designed according to the existing stress joints and the marine environment in service. Therefore, when the marine environment and production requirements of the service area change, the designed stress joints will be difficult. Meet the functional and economical requirements in this marine environment

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