Viv and/or drag reduction device installation systems and methods

Abstract

There is disclosed a system comprising a structural element; a transport tool carrying a plurality of VIV and / or drag reduction devices; and an installation tool adapted to remove a VIV and / or drag reduction device from the transport tool and to install the device around the structural element.

Description

FIELD OF INVENTION[0001]The present disclosure relates to VIV and / or drag reduction device installation systems and methods. In particular to installation systems and methods for use underwater.BACKGROUND[0002]Structural elements can be installed at sea from a floating vessel using a J-lay configuration where the structural element is held vertically on the vessel and dropped vertically into the water and then when it reaches the bottom of the body of water, it lays horizontal, or alternatively structural elements can be installed in a S-lay configuration where the structural element is held horizontally on the vessel, drops to vertical through the body of water, and then rests on the bottom of the body of water in a horizontal configuration. Other configurations for installing a structural element from a vessel in a body of water are also known.[0003]Referring now to FIG. 1, system 100 for installing structural element 114 on bottom 116 of body of water 112 is illustrated. System 1...

AI Technical Summary

Benefits of technology

[0017]Another aspect of the invention provides a method comprising moving a transport tool carrying a plurality of VIV and / or drag reduction devices near to the structural element; moving an installation tool near to the transport tool; removing one or more VIV and / or drag reduction devices from the transport tool to the installation tool; and installing the one or more VIV and / or drag reduction devices around the structural element with the installation tool.

[0018]Advantages of the invention include one or more of the following:

[0019]an improved apparatus and method for installing VIV and / or drag reduction devices;

[0020]an apparatus for and new and improved methods of installing VIV and / or drag reduction devices in a flowing fluid environment;

[0021]an apparatus for and new and improved methods of installing VIV and / or drag reduction devices with fewer trips required to the surface for additional devices; and

[0022]an apparatus for and new and improved methods of installing VIV and / or drag reduction devices which does not require retrieving the tooling to the surface to reload the tooling with additional devices.

Problems solved by technology

These vibrations may be caused by oscillating dynamic forces on the surface which can cause substantial vibrations of the structural element, especially if the forcing frequency is at or near a structural natural frequency.

If the frequency of this harmonic load is near the resonant frequency of the structural element, large vibrations transverse to the current can occur.

These vibrations can, depending on the stiffness and the strength of the structural element and any welds, lead to unacceptably short fatigue lives.

In fact, stresses caused by high current conditions in marine environments have been known to cause structural elements such as risers to break apart and fall to the ocean floor.

For instance, a riser pipe that is vibrating due to vortex shedding will disrupt the flow of water around it more than a stationary riser.

This may result in more energy transfer from the current to the riser, and hence more drag.

Deploying structural elements may damage the VIV and / or drag reduction devices by the installation, for example by the stinger or rollers during an S-lay installation.

A pre-installed VIV and / or drag reduction devices may be damaged if it passes over the stinger.

In addition, holding onto a structural element with a tensioner may damage VIV and / or drag reduction devices.

In addition, VIV and / or drag reduction devices may have a useful life less than the life of the structural element to which they have been applied.

Currently, the number of devices that can be transported to the desired depth and location is limited, and may lead to increased costs and installation time to transport additional devices to the desired depth and location.

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