In February, Deepwater Corrosion Services performed anode retrofits on 2 subsea development systems in 73 hours. These deep water installations, located in water depths ranging from 775 to 1,750 feet, consisted of:
• 4 flowlines, ranging in length from 3 to 9 miles, each
• 4 well trees
• 2 flowline manifolds
• 2 umbilical termination units
The installation was accomplished utilizing a DP-equipped ROV Support Vessel equipped with two ROVs. An ROV essentially watches the RetroPod craned down to the seabed, adjacent to the asset, and sets the RetroClamp onto the target member or pipeline. Electrical continuity and CP measurements were monitored using Deepwater’s Polatrak Deep-C Meter and ROV II Probe.
The CP design was optimized in a manner that minimized the number of installation sites, but allowed for maximum flexibility with anode array placement. This design feature enabled the installation team to quickly alter the game plan when they encountered a major escarpment at one lay-down site.
The innovative RetroClamp system, allows the anode array to be clamped and electrically connected to a member of any shape or size, completing the circuit necessary for the cathodic protection system to begin polarizing the structure or pipeline. The RetroClamp can be installed by diver or ROV (ROVs in this case).
|Subsea photo from the installation.||RetroClamp connected to flowline; PolaTrak ROV II Probe testing for electrical continuity.|
|As-left survey of RetroPod and RetroClamp connected to flowline.||ROV disconnecting crane rigging from RetroPod.|
|Overview of RetroClamps on East and West flowlines||RetroClamp engaging the member of a Well Tree|
|Photo subsea from theinstallation.||Custom clamp engaging the member of an Umbilical Termination Assembly.|
|Two RetroClamps engaging the member of a Well Tree.|