Method for analyzing out-of-plane motion of steel catenary riser

Abstract

The invention relates to a research method for marine deepwater risers, and particularly relates to a method for analyzing the out-of-plane motion of a steel catenary riser. By using the method disclosed by the invention, an improvement on the existing technique for analyzing the out-of-plane motion of a steel catenary riser is performed, the rigid body motion of the out-of-plane motion of a steel catenary riser is taken into consideration, an analytical mode of the out-of-plane motion of a steel catenary riser is built, and the rigid body rotation of the out-of-plane motion of a steel catenary riser is added, so that the analysis on the out-of-plane motion of a steel catenary riser is more consonant with an actual motion state.

Description

technical field [0001] The invention relates to a research method of an ocean deepwater riser, in particular to a method for analyzing the out-of-plane motion of a steel catenary riser. Background technique [0002] Steel catenary risers, umbilical cables and flexible risers are important equipment for deep-sea oil and gas development. One end of them is connected to the floating platform and hangs freely to the seabed, forming a catenary. The first point where the steel catenary riser, umbilical and flexible riser contacts the seabed is called the touchdown point, and the section from the floating platform to the touchdown point is called the suspension section. The other end of the steel catenary riser, umbilical and flexible riser is connected to the wellhead (production riser) or subsea terminal (transport riser) or subsea manifold, from the touchdown point to the wellhead, subsea terminal or subsea manifold A segment of is called a streamline segment. [0003] Steel c...

AI Technical Summary

Problems solved by technology

[0016] 1. The influence of the acceleration caused by the rotation of the rigid body on the inertial force and additional mass of the steel catenary riser is not considered

[0017] The inertial force item in the dynamic balance equation of the structure (the first item in the bending motion equation of the beam) should be the absolute acceleration of the structure, but the prior art uses the acceleration caused by bending deformation, ignoring the acceleration caused by the rotation of the rigid body , therefore, the calculated value is small

[0018] 2. The influence of the speed caused by the rotation of the rigid body on the additional damping and hydrodynamic load of the steel catenary riser is not considered

[0019] The damping force item in the dynamic balance equation of the structure (the second item in the bending motion equation of the beam) is divided into two parts, one part is the damping of the structure itself (the first part of the second term in the beam's bending equation of motion), and the other part is the additional damping of the hydrodynamic force (the second part of the second term in the bending motion equation of the beam), the size of this part of the damping depends on the relative velocity of the structure and the fluid, therefore, it should be the absolute velocity of the structure, but what the prior art uses is that the bending deformation causes The velocity caused by the rotation of the rigid body is ignored, so the calculated value is too small

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