Careers FPSO Corrosion Protection: HVTS Cladding for Offshore Process Vessel
An offshore O&G production facility in Guyana operates a high-value FPSO supporting continuous oil production in a demanding marine environment. The facility’s deaeration tower plays a critical role in maintaining process reliability by removing dissolved gases and protecting downstream systems. Maintaining the integrity of this vessel is essential to safe operation, uptime, and long-term production certainty.
During inspection planning for a scheduled shutdown, the facility identified extensive internal degradation within the deaeration tower. The priority was to restore the asset’s pressure boundary integrity, eliminate ongoing corrosion risk, and implement a solution capable of supporting long run lengths without introducing schedule or safety risk during the turnaround.
T25-35800
Severe Internal Corrosion and Metal Loss in an Offshore FPSO Pressure Vessel
Detailed internal inspection of the FPSO deaeration tower revealed widespread failure of the existing organic coating system, particularly in the upper chamber above the first-stage seal plate. Approximately 90% coating failure was observed in this zone, accompanied by active base metal wastage, localized pressure boundary breaches, and below-minimum thickness readings. Mechanical repairs were required in multiple locations, including weld build-ups and shell insert patch plates.
In the lower chamber, corrosion was less concentrated but remained widespread, with accelerated deterioration observed above the normal liquid level, a common corrosion zone in offshore oil & gas process vessels operating in aggressive marine environments.
Given the vessel’s operating environment and history of coating failure, the facility required a long-term corrosion mitigation strategy capable of permanently restoring pressure boundary integrity, extending asset life, and reducing future shutdown risk within the confined space constraints of an offshore FPSO.
Evaluating Long-Term Protection Options for a Critical Vessel
The facility evaluated several repair strategies to address the corrosion damage, including localized weld repairs and reapplication of an organic coating system. While these approaches offered short-term remediation, they did not adequately address the aggressive internal environment or provide confidence in long-term performance.
IGS was selected based on its ability to deliver HVTS cladding as a high-density protective solution that could be installed efficiently during the shutdown window. The approach provided the facility with a reliable means to permanently isolate the pressure boundary from the corrosive process environment while avoiding distortion, extended schedules, or increased safety exposure.
HVTS Cladding Delivered Safely and Efficiently Offshore
IGS deployed HVTS cladding to the internal pressure boundary of the deaeration tower to stop corrosion and restore asset integrity. The scope included extensive surface preparation, mechanical repairs, and controlled application of cladding and interface protection systems.
All work was executed offshore during the planned shutdown window. HVTS cladding activities were completed within the designated critical path schedule.
The work was performed within a confined offshore environment with engineered ventilation, rope access rescue support, and structured safety oversight throughout execution.
Our focus was not just repairing damage, but giving the offshore production facility confidence that this vessel will perform reliably for years to come. HVTS cladding allowed us to deliver permanent protection without disrupting their operating strategy.
– Eric Van Der Spuy, Senior Project Manager, IGS
Asset And Scope Overview
| Item | Description |
|---|---|
| Asset Type | Deaeration Tower |
| Challenge | Corrosion-driven internal metal loss |
| Primary Damage Mechanism | Oxygenation pitting, up to 10 mm deep |
| Execution Environment | Offshore, confined space |
Initial Condition Assessment
| Inspection Area | Findings |
|---|---|
| Upper Chamber | ~90% of the internal coating had failed, with extensive metal loss and damage in multiple areas of the vessel wall |
| Lower Chamber | Widespread coating deterioration, most aggressive above liquid level |
| Repairs Required | Weld buildup at 13 locations and installation of 2 shell insert plates |
During execution, additional organic coating repairs were incorporated where inspection revealed greater-than-anticipated degradation, ensuring complete corrosion mitigation prior to final protection
Surface Preparation and Quality Controls
| Activity | Result |
|---|---|
| Soluble Salt Testing | Reduced from 200–300 mg/m² to <20 mg/m² (safe and acceptable levels) |
| Abrasive Blasting | Full removal of failed organic coating |
| Surface Defect Repairs | 64 locations repaired and ground to acceptance standards |
IGS HVTS Cladding Application
| Parameter | Specification |
|---|---|
| Cladding Material | IGS HVTS cladding |
| Cladded Area | 332 m² / ~3,575 ft² |
| Coverage | Shell, dish ends, internals, nozzles, manways |
Restoring FPSO Asset Integrity Without Extending Turnaround Downtime
The HVTS cladding system eliminated active corrosion mechanisms while stabilizing previously damaged regions of the pressure boundary. Installation was completed entirely within the planned FPSO shutdown and critical path turnaround window, avoiding extended outage duration, additional welding campaigns, or unplanned production losses. By eliminating the need for vessel replacement or repeat short-cycle repairs, the facility significantly reduced lifecycle maintenance risk and future corrosion-related downtime exposure.
The result was a durable, high-density corrosion protection solution that extended asset life, improved long-term reliability, and strengthened overall asset integrity management strategy.
Results & Outcomes
| Outcome | Value Delivered |
|---|---|
| Corrosion Risk | Eliminated in clad regions |
| Pressure Boundary Integrity | Restored and stabilized |
| Schedule Performance | Completed within critical path window |
| Safety Performance | Zero incidents |
| Quality Compliance | 100% within specification |
Permanent HVTS cladding restored pressure boundary integrity and reduced long-term corrosion risk in a critical offshore process vessel.
That’s Asset Vitality.
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