In 2025, the decommissioning project for the South Angsi Alpha (SAA) platform off the coast of Terengganu, Malaysia, fully showcased the huge advantages of rigless decommissioning technology. By avoiding the use of expensive heavy-lift vessels and drilling rigs, the project team successfully delivered Malaysia's largest 'rig-to-reef' decommissioning project, achieving minimal delays, efficient collaboration, and maximum cost-effectiveness.
This case study explores how a rigless solution-including reverse installation methods, custom lifting systems, and ROV-assisted underwater cutting-successfully completed the decommissioning of a 4,000-ton platform, setting a new benchmark for responsible offshore decommissioning in Southeast Asia.
1. Project Overview
|
Project |
South Angsi Alpha (SAA) Platform Decommissioning |
|
Location |
130 km off the Terengganu coast, Malaysia |
|
Platform Type |
4,000-metric-ton, four-legged Mobile Offshore Application Barge (MOAB) |
|
Water Depth |
Approximately 70 meters |
|
Project Scale |
Largest decommissioning and reefing operation in Malaysian waters |
2. Drill-free solution: How to make it happen
Reversed Installation Method
Marine Masters used the reversed installation method-essentially running the installation process in reverse-to remove the MOAB. This approach eliminated the need for heavy-lift vessels by using the platform's own structural integrity and carefully planned load transfers.
Marine Masters.
Custom-Designed Lifting Systems
The project developed custom-designed lifting systems specifically to avoid the use of expensive heavy-lift vessels. These systems were engineered to work within the platform's space and load constraints.
ROV-Assisted Underwater Cutting
Multiple cutting-edge techniques were deployed for underwater operations:
Remotely operated underwater cutting (assisted by ROVs)
High-speed PVL hand cutting (by divers)
Special procedures developed for each cutting task
Strand Jack Solution
Heavy lifting specialist Sarens deployed 16 units of 450/650-ton strand jack combinations to lower the MOAB onto the transport barge. This was the first time Sarens APAC had used a strand jack solution for a decommissioning task.
3. Advantages of a Drilling-Free Plan: Key Benefits
Cost-effectiveness
By avoiding the use of heavy lift vessels and drilling rigs, the project achieved significant cost savings. Combining oil and gas industry experience with salvage thinking has proven to be key to cost-effective execution.
The no-rig approach eliminates the following costs:
Drilling rig mobilization and day-rate costs
Heavy-lift vessel charter costs
Associated marine support vessel requirements
Project efficiency
Faster mobilization and demobilization
Reduced offshore personnel requirements
Streamlined operations without rig constraints
Safety
Fewer personnel required offshore
ROV-assisted cutting reduced diver exposure
Remote operations minimized high-risk zone occupancy
Environmental sustainability
Rig-to-reef repurposing: The jacket was cut at -55 meters and laid on the seabed as artificial reef structures
Reduced carbon footprint: Fewer vessels meant lower fuel consumption and emissions
Marine ecosystem enhancement: The reef structures promote biodiversity, sustainable fisheries, and ecotourism |
Minimize platform interference
The rig-less solution executed wellhead recovery operations without disrupting platform infrastructure. The compact, modular approach was ideal for the space-constrained MOAB.
The 2025 Maera Terengganu South Angsi Alpha decommissioning project in Malaysia proves that rigless decommissioning is not just a concept - it's a proven, scalable, and cost-effective reality.
