CPRO 135 – ZULF Field Jacket Demolition and Slipover Installation
Project
CPRO 135 – ZULF Field Jacket Demolition and Slipover Installation
Client
Saudi Aramco
Contractor
Algihaz Marine Contractor (AMC)
Location
ZULF Field, Kingdom of Saudi Arabia
Project Period
October 2025 – January 2026
Algihaz Marine Contractor (AMC) was awarded the contract to perform the demolition of an existing jacket at ZULF Field without removing the well, followed by the installation of a new slipover jacket at the same location. This method required precise and controlled cutting operations to ensure structural separation while maintaining well integrity.
To support this operation, OCS was engaged to execute the dredging and cutting scope. OCS carried out dredging of the jacket legs to expose the required cutting zones, followed by internal cleaning of the jacket piles using a high-pressure pump system capable of reaching up to 60 m from the top of the pile, ensuring clear access for cutting activities. Internal cutting was then performed using an Internal Pipe Cutter (IPC) with abrasive water jet technology, while external cutting was executed using a Diamond Wire Cutter (DWC). The entire spread was successfully mobilised from Singapore and Batam to Saudi Arabia within a tight one-month preparation window.
OCS executed a total of five internal cuts across multiple strings within the jacket legs using the IPC system. The Diamond Wire Cutter (DWC) was reserved for the final cut, allowing it to remain in position while the top section of the jacket was removed in a controlled manner. In addition, cutting using the Water Abrasive Suspension (WAS) system was carried out on the same jacket to support the overall demolition scope. The jacket was ultimately split into three sections to enable safer and lighter recovery operations.
During execution, a key technical challenge was encountered due to the presence of insert piles within the jacket legs, which reduced the internal diameter and restricted tool access. Despite this constraint, the OCS team adapted by modifying and downsizing the IPC system to suit the reduced internal diameter, allowing the cutting operations to proceed without disruption to the overall sequence.
The project was completed successfully, demonstrating OCS’s ability to integrate cleaning, internal and external cutting methods, and execute complex multi-string operations under constrained subsea conditions while maintaining schedule and operational efficiency.
