How Does Heavy Lift Work?

With major drilling and production facilities located offshore, the oil and gas industry must rely on an efficient and safe way to install this equipment. Through experience and innovation, the industry has developed a number of ways to overcome heavy lift challenges offshore.

There are two main methods of marine installation of heavy equipment. The conventional way to install major facilities, such as topsides and production equipment, is through lift barges, while floatover installation has been gaining acceptance as a method of offshore installation, as well. Additionally, new techniques for performing heavy lift operations are being developed.

Lift Barges

For decades, heavy lift cranes have been deployed in offshore oil and gas fields for installation purposes. Heavy-lift barges are used to both transport the equipment offshore and lift it into place via powerful cranes.

J. Ray’s Derrick Barge 27 Performs Heavy Lift OperationsSource: J. Ray McDermott

With lifting capacities greater than 10,000 tons, heavy lift cranes are many times used in single-lift operations. In other words, the equipment, such as topsides, are lifted from the barge and mated with the facility jacket in one heavy lift.

Heavy Lift Operations in Asia PacificSource: J. Ray McDermott

Requiring less muscle, major marine installations can be divided into modular lifts. For example, a processing facility can be fabricated in multiple modules that are then installed offshore one by one.

Floatover Installation

Gaining popularity for being both time- and cost-efficient, floatover installation through semisubmersible vessels is a viable option for marine installation operations. This method of marine installation requires a vessel with a hydraulic pumping system that allows the vessel to submerge itself under the water, and then reemerge.

Intermac 650 Getting into Location for Floatover OperationsSource: J. Ray McDermott

Allowing onshore mating of equipment, floatover marine installation involves transporting the equipment to location, as well as installing it. Here, the semisubmersible vessel floats into place and takes on water to partially descend under water. The equipment is lowered into place and installed, and the vessel then floats out from under it. Then, hydraulic pumps drive the water out of the vessel, which reemerges from the water.

Innovative Marine Installation Solutions

Rather than depending on a heavy lifting crane or submerging into the water, SeaMetric has developed two new vessels to perform heavy lift marine installations. This solution provides twin vessels equipped with numerous lifting arms on one side of each vessel.

SeaMetric's Heavy Lift Vessels

Lifting Arms Extend to Enable Heavy Lift Installations Offshore

These heavy transport vessels straddle the equipment on either side, extending their lifting arms to the equipment. The arms then lift the equipment and then lower it into place for installation.