Despite a dearth of hurricane activity in 2006, speakers on a storm preparedness panel at the Offshore Technology Conference (OTC) in Houston Tuesday still had plenty to talk about. After all, the industry remains on the mend from the momentous 2005 hurricane season and digesting the lessons learned from the one-two punch of hurricanes Katrina and Rita.
Indeed, two years later, 2-3% of pipeline capacity in the Gulf of Mexico is still out of service. While final repairs are under way, operators, meteorologists, service companies and others are wondering whether the stakes have been permanently raised in the Gulf.
“After [Hurricane] Ivan we got our first warnings that something was going on out there that we didn’t understand,” said Pat O’Connor, BP America Inc. senior advisor for structural and offshore engineering. “We cannot go and just change [rig design] criteria simply because a bigger wave comes in.”
However, O’Connor and others on the panel acknowledged that changes are in order, particularly with regard to design and performance standards established by the American Petroleum Institute (API), which have been under review. O’Connor said that from the 1980s to the early 2000s the industry was “reasonably comfortable” with the standards established. That is no longer the case, he said.
Hurricanes Ivan and Katrina along with Opal of 1995 are the three biggest wave-making hurricanes on record, and they all occurred within a 10-year span, noted James Stear, an ocean engineer with Chevron.
One of the changes that has been made to API standards is the acknowledgment that hurricane frequency and intensity varies across the Gulf of Mexico. For this reason the Gulf has been divided into four regions: west, west-central, central and east. The Gulf’s central region, where Ivan and Katrina made landfall, is the most active. The west-central region, where Rita made landfall, is somewhat less so.
From the experience of 2005 it has become clearly apparent to the industry that one section of the Gulf is not necessarily like another. Besides looking at where hurricanes usually track, forecasters also are looking at loop currents of warm water deep in the Gulf. Where loop currents are present, surface cooling of water is reduced, creating conditions conducive to the formation of more severe storms. Stear explained that a hurricane works like a heat pump. When a hurricane is parked temporarily over an area of loop currents its intensity is likely to increase. Regionally, wind and wave extremes tend to overlay pockets of deep warm water, he said.
Wave extremes are particularly important, particularly when waves are so high that they breach the lowest levels of an offshore rig. Of rigs destroyed by hurricanes Katrina and Rita, 60% experienced waves higher than their lowest decks, said Frank Puskar, president of Houston-based Energo Engineering.
As bad as the damage wrought by Katrina and Rita was, it could have been worse had the vintage of rigs in the Gulf of Mexico been older. Puskar said that 50% (58) of the fixed platforms destroyed by the storms were installed prior to 1970, prior to the API’s RP 2A guidelines. Twenty-five of the platforms destroyed were installed between 1970 and 1979. Of the platforms installed between 1980 and the time the storms hit, 33 were destroyed.
The API will be hosting workshops in New Orleans on July 17 and Houston on July 19 on its interim bulletins on standards and practices for Gulf of Mexico operators. More information can be found at the API website, www.api.org.
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