The Tallest Oil Rig in the Sea Ever Installed
Posted on Jun 14, 2025 at 03:06 PM
In the Gulf of Mexico, the tallest oil rig ever deployed at sea is the Petronius Compliant Tower. Standing 640 meters (2100 feet) from the seafloor to the top, it was the world's tallest freestanding building until 2010, when Dubai's Burj Khalifa overtook it.
It extracts 100 million cubic feet of gas and 60,000 barrels of oil per day and was built to flex and sway in deep-water conditions.
Originally constructed by Texaco and Marathon Oil, the tower is situated at a water depth of 535 meters in Viosca Knoll Block 786. It's currently run by the Chevron Corporation.
The Compliant Tower
Compliant towers move or sway in response to winds, waves, and ocean currents, whereas the more typical fixed platforms stay put. Rigid structures may not be able to survive in deep waters with strong winds or currents, so this flexibility is necessary.
Compliant towers, such as the Petronius Tower, are narrow, flexible towers with a pile foundation on the seafloor, suitable for water depths between 400 to 1000 m, assembled in sections and installed using specialized equipment.
Building the Tallest Oil Rig in the Sea
J. Ray McDermott built a $140 million steel tower in Morgan City, Louisiana. The deck was assembled in two main sections, with flexpiles acting as shock absorbers and a top section tapering to the surface level, built by Gulf Island Fabrication in Houma, Louisiana.
The North Module, installed in 1998, was a 3600-tonne South Module with production equipment and crew accommodation. It was lost overboard, causing a million-dollar loss and project delays in 2000. The construction project amounted to a total cost exceeding $500 million.
Courses in Maritime Engineering include naval architecture and offshore structures, a speciality that focuses on designing, building, and maintaining ships and offshore platforms, such as oil rigs.
The Tallest Oil Rig is Now Fully Assembled
The jacket bottom was launched from the Intermac 650 barge, self-righted, and lowered onto seabed piles using underwater winching systems.
The platform was assembled by lifting the top section using the DB-50 barge's crane, and the North Module was lifted in 1998. The South replacement was installed by Saipem S7000 in April 2000, marking the complete assembly.
Despite initial setbacks, the project became a crucial part of deep-water oil production in the Gulf of Mexico region and a testament to offshore engineering resilience.
The Petronius Tower, situated 210 km southeast of New Orleans, Louisiana, is a significant US oil production hub. It houses drilling and production risers connected to subsea wellheads, a topside weighing 43,000 tonnes, and various facilities.
The platform features HVAC, emergency power, waste management, and potable water systems, and can accommodate 60–70 personnel per shift rotation.
Safety & Risk Mitigation
The Petronius Platform, a compliant tower designed to withstand ocean currents and deflect up to 2% of its 640 m height, ensures stability during storms and adheres to SPCC guidelines for secondary containment, leak monitoring, and overfill protection.
The company adheres to updated HSE protocols post-Deepwater Horizon, which involve risk assessments, frequent drills, and real-time monitoring.
The equipment includes automatic shutoff valves, blowout preventers, and remote monitoring systems. Crew members undergo annual training on spill response, fire drills, evacuation, PPE usage, and medical emergencies, and regular spill-response exercises test readiness and resource deployment.
Ultimately, the Petronius Compliant Tower, the tallest maritime oil rig, showcases deep-water innovation and engineering feats. As the offshore oil industry transitions to green energy, managing risks is crucial for the marine environment and economy, as oil spills continue.
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