Remove and Replace Vent Stack Tower

DIALOG Fitzroy was contracted by Shell Todd Oil Services (STOS) to perform the high risk job of removing and replacing the top two sections of a 96 metre high offshore vent stack for the Maui A  oil rig in the Tasman Sea.  The project involved the fabrication of a new top section, logistics coordinationof the old stack from and the new stack to the platform including bringing a crane to the platform.

Scope of Work

• Planning & Engineering: Detailed design for rigging, structural support, and material
• Logistics Management: Coordination of shutdown process for gas venting, delivery of additional cranes to the platform, and support vessel coordination to remove old vent stack

Removal of Old Stack:

• Rigging Setup: Deployment of winches and lifting davits from the platform or an adjacent barge.
• Cutting/Disconnecting: Cut and unbolted the corroded section, managing potential spark risks.
• Lifting: Hoisted the old section away from the platform

Installation of New Stack:

• Hoisting & Securing: Lifted the new component into place and secured it to the main stack and boom arm.
• Waste Management: Removal of old stack and materials from site via support vessel
• Testing & Commissioning: Verify the new installation, ensuring it meets flare system integrity and safety requirements.

 Outcomes and Value Delivered

• Enhanced Safety & Compliance: The new vent stack was installed with no incidents and meeting all STOS requirements
• Extended Asset Life: Replacement of the corroded section prolonged the operational life of the Maui A platform and avoided costly emergency repairs.
• Operational Continuity & Reduced Downtime: Careful planning and execution minimized shutdown time, allowing production to resume quickly.
• Health and Safety: Zero incidents while working in extreme conditions