Description

Typically, decommissioned platforms are safely removed and taken ashore for disposal per regulatory requirements. But an alternative for the Eugene Island 331A platform was for Shell to recycle and transform it into a valuable marine habitat as part of "Rigs-to-Reef".

Application

EI 331A was originally installed in 1972 as a fixed structure in 242’ water depth. In September 2008, the platform was hit by Hurricane Ike. While the topsides was deemed salvageable, Shell determined it was not feasible to repair the jacket due to the number of broken structural members located below the water surface. Shell then began to assess this piece of infrastructure as a potential candidate for the Rigs-to-Reef program.

Results

The final jacket reefing took place on September 20, 2009, after a topsides and deck removal campaign was completed. The steel jacket structure, comprised of eight legs and weighing almost 3000 tons, was cut loose from the ocean floor utilizing special cutting tools to make cuts 15’ below the mudline. No explosive cutting was used during the project. The jacket was lifted and then towed a short distance, where it was toppled to its final position. Underwater ROV cameras documented fish and other marine life following the jacket during its tow operation and reefing.

Significance

This was the first major Rigs-to-Reef project that Shell had done over 15 years - the learnings will be beneficial for future abandonments. In addition to the positive impact of the rig-turned-artificial reef on fisheries enhancement, there are also mutual financial benefits realized by both the operator and the state. States utilize these donations to both manage the artificial reefing sites and study their long-term benefits to marine habitats. Following the final reefing, Mr. Robert Barham, Secretary of the LDWF, called the reefing of the EI331A jacket the "gold standard" for reefing projects.

You can access this article if you purchase or spend a download.