Supporting subsea pipeline decommissioning in the Gulf of Thailand

Centurion is supporting one of the Asia-Pacific’s largest subsea pipeline decommissioning campaigns, an ambitious multi-phase project in the Gulf of Thailand that began in March 2024. Working alongside a leading subsea contractor, we’re providing a full suite of cutting and recovery tools as well as control cabins to enable the safe and efficient removal of over 335km of aging pipeline.

With Phase 2 set to begin in July 2025, this project highlights the critical role Centurion is playing in delivering practical, cost effective and safe solutions for complex offshore decommissioning.

The client

The client, a leading subsea services provider, is responsible for the safe, efficient and cost-effective removal of aging subsea infrastructure. Their decommissioning efforts involve complex challenges, including the recovery of 335km of subsea flowline networks while adhering to strict environmental and regulatory requirements.

Phase 1 - started March 2024

Client requirements and challenges

The project involved recovering 64 pipelines, ranging from 2 km to 21 km in length and 6” to 18” in diameter, many of which were encased in concrete weight coating (CWC).

Key challenges identified included:

Ensuring efficient and cost-effective pipeline recovery

Managing variable pipeline conditions and information gaps with legacy assets

Meeting environmental regulations and managing pollution risks

Adapting to external weather conditions that could potentially affect project timelines

Selecting the right cutting tools to optimize performance and reduce downtime.

Our solution

Centurion worked closely with project stakeholders to help determine the most efficient removal methods, balancing environmental regulations, operational constraints, and safety. The project utilised multiple methodologies, including:

S-Lay technique

Cut and recover approach using shears and chopsaws

Ongoing collaboration between the operator, EPRD contractor, and service providers, along with real-time project learnings has been key in refining methodology, equipment selection, and execution. This includes:

Tailored cutting tool selection based on pipeline specifications

Continuous refinement of cutting methodologies

System Integration Testing (SIT) to validate equipment performance.

The results

Centurion’s contributions have significantly improved the efficiency of the decommissioning project, achieving to date (as of March 2025), the following:

56 pipelines removed in 12 months, with 8 remaining

Over 22,000 shear cuts and 5,000 chopsaw cuts completed

Optimized blade selection for different pipeline conditions:

Tungsten Carbide Tipped (TCT) Blades: Fastest cuts recorded – 2” pipe in 1 minute, 16” pipe in 4 minutes

Diamond Blades for CWC: Cutting times – 16” CWC pipe in 12 minutes, 18” CWC pipe in 18 minutes

Enhanced shear performance with Genesis GSS775 shears for precise and efficient cutting

Reduction in equipment downtime.

Phase 2 - starts July 2025

Phase 2 which starts in July 2025, adds another 12 pipelines totalling 85km, ranging from 140m to 13.7km in length and 6” to 12” in diameter. This phase is being delivered through a collaboration between Centurion teams in Singapore and Australia, supplying a full package of subsea tools, control cabins, recovery systems and offshore-certified equipment, all pre-tested, integrated and ready to go.

The three-month operation spans 24/7 vessel activity aboard the DSV Van Gogh and DLV HQ1200.

Conclusion

Centurion's expertise in cutting and recovery solutions has played a key supporting role in the success of this large-scale decommissioning project. By employing a collaborative approach, innovative methodologies, and adaptive execution strategies, we are contributing to an efficient, cost effective and safe pipeline removal process.

With the demand for pipeline decommissioning surging worldwide and set to grow even further, these insights will be invaluable in helping clients optimise future projects.

Contact information

For more information contact the team in Perth, Western Australia at CSSAU@centurionaprs.com or in Singapore: +65 6863 4470 or CSSSG@centurionaprs.com

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