Distance-variable arrangement method for marine riser vibration suppression devices

Abstract

The invention discloses a distance-variable arrangement method for marine riser vibration suppression devices. The method comprises the steps that firstly, according to the actual sea condition and the inherent characteristics of risers, vortex-induced vibration fatigue analysis is carried out on the risers, and according to the analysis result, whether the vortex-induced vibration suppression devices need to be mounted or not is confirmed; and secondly, according to the vortex-induced vibration fatigue damage risk level of the risers, the vibration amplitude and the drag force loads, the risers are divided into the fatigue damage high risk segment, the low risk segment, the risk-free segment and the transition segment, then different preset and mounting manners are adopted for arranging the vibration suppression devices, and finally arrangement work of the vibration suppression devices is completed. The axial areas of the risers are divided into the fatigue damage high risk segment, the low risk segment, the risk-free segment and the transition segment, and different distances are adopted in different fatigue damage areas to arrange the vibration suppression devices. By means of the arrangement method, the suppression effect of the vibration suppression devices to vortex-induced vibration can be guaranteed, and the drag force loads borne by the risers can be greatly reduced.

Description

technical field [0001] The invention relates to the technical field of marine riser laying, in particular to a method for arranging vibration suppression devices of variable pitch marine risers. Background technique [0002] At present, the riser is a connecting pipe used to connect the offshore platform and the subsea wellhead in the deep-sea oil and gas development system. Except that the upper and lower ends of the standpipe are connected and fixed, the rest of the riser does not have any fixing and support. Therefore, when the sea current flows through the surface of the standpipe, at a certain flow rate, vortices are alternately formed on both sides of the standpipe, and the vortex shedding will produce a periodic variable force on the standpipe, causing the standpipe to vibrate in the vertical flow direction. Since the vortex will fall off with the wake of the ocean current fluid flow, when the vortex shedding frequency is close to the natural frequency of the standpi...

AI Technical Summary

Problems solved by technology

[0003] In recent years, for omnidirectional vortex-induced vibration suppression devices, there are widely used full-coverage schemes or equal-space coverage schemes. These schemes have redundant performance and high cost. Concentration leads to fatigue damage easily, and the drag force load is large, there are problems in economy, safety and efficiency

Images