Hurricanes Turn Rigs Into Wrecking Balls

corncam

19 years ago

The Mobile Register has a brilliant investigative report today on lax federal regulation of oil rig moorings. Reporters Ben Raines and Bill Finch found that some types of rigs are not even required to withstand hurricane force winds.

First, some background – there are two types of rigs in the Gulf of Mexico: fixed and mobile. Fixed rigs are permanently attached to the sea floor, and they are typically used in water up to 1500 feet. Mobile rigs are designed to move from one place to another, even though some of them spent their whole working lives in one spot. Some mobile rigs use extendable legs to stand on the botton, while others float in the water, and are held in place by anchors. The rigs with legs are called jackups, while the floaters can either be semi-submersibles or tension leg platforms. (See Wikipedia for a short introduction to various rig types.)

Throughout this crisis, officials of the Mineral Management Service have claimed that offshore oil platforms were designed to withstand a Category 5 hurricane, but the Mobile Register found that was not true.

Last week, the Register reported that permanent — or “fixed” — platforms in the Gulf are only required to withstand winds and waves typical of a Category 2 or Category 3 hurricane, in spite of assertions by federal authorities that these facilities are being designed to withstand Category 5 conditions. In the past year, four storms crossed the rig fields with Category 4 or 5 winds.

But in the recent storms, a large percentage of the damage is being attributed to mobile drilling units — floating platforms of various designs that prospect for oil before the permanent production platforms are erected.

Register research suggests why so many of these mobile drilling units are running free: Federal and industry anchoring requirements for many mobile drilling units — particularly the semisubmersible drilling rigs that were prone to break free during Rita — are designed to account for winds and waves associated with a minimal Category 1 hurricane. In many cases, those rules allow mobile drilling units to set anchors and mooring systems that would not even account for hurricane-force winds.

More …
These standards were clearly insufficient after so many rigs were torn loose from their moorings during Hurricane Ivan last year. But even then, the industry resisted any changes to the regulations. The current regulations are barely adequate to protect against a big tropical storm, much less a Cat 5 hurricane. Up till now, no one was really concerned, because there haven’t been many big hurricanes in the western and central gulf in recent decades. So it was business as usual after everyone finished picking up after Ivan.

But no changes were made to the governing industry design standards developed by the American Petroleum Institute, which require that moorings and anchoring systems for mobile units be designed to withstand a once-in-10-year design storm if operating in close proximity to another structure, and a five-year storm if operating at some distance from other structures, though the regulations do not specify the distance. In some conditions, companies are allowed to design for “no less” than a one-year storm …
The five-year design storm, with winds of about 72 mph and a significant wave height of 27 feet, would not even ac count for hurricane-force winds.

Naturally, once reporters started asking questions, everyone clammed up.

The Register asked both federal officials and engineers with the American Petroleum Institute to define a one-year storm, a five-year storm and a 10-year storm. Neither the Minerals Management Service nor the industry-funded institute were willing to do so. The industry group informed the Register via e-mail that it was up to each oil company to define what a five- or 10-year storm would be, in terms of wind speed, wave height and current.

In fact, the situation is so bad that the MMS and the Coast Guard cannot even agree on which of them is responsible.

“I know MMS told you that is our responsibility …” said Jolie Schifflet, with the Coast Guard. “… however, the specific element you asked about, the forces these rigs must stand up to, that is set by MMS.”

The only hope I see for stronger regulations is pressure from within the industry. It appears that a lot of the damage to fixed or jackup platforms may have come from roving semi-subs that tore loose from their moorings. Of course, the semi-sub owners fiercely dispute that assertion, and no one knows for sure what is happening far out to sea during a hurricane. Regardless of who is to blame, the industry has lost billions of dollars worth of hardware, not to mention shut-in production and the sheer time it will take to get back in business. This may be a case of “please stop us before we do it again”. Where normally regulation adverse companies ask for federal standards to protect themselves from their own cheapness.

(Hat tip to The Oil Drum. They have comprehensive hurricane damage coverage.)

0 0 votes

Article Rating