Jack up rigs, winter ice don’t mix

By Robert Archibald

Cook Inlet is a dynamic and ever-changing environment, especially in winter.
Temperatures fluctuate greatly from year to year, as do differences in ice concentrations. There’s no rhyme or reason to ice conditions from winter to winter.
A jack up rig has never worked in the ice of Cook Inlet. The Endeavour may have been built to North Sea standards, but this is not the North Sea. Rigs that have worked the Inlet have always been out before the ice showed up and never even entertained the idea of drilling during the winter.
Reasons why winter operations may be hazardous:
• 1. Weather conditions at Cosmopolitan sites can vary from ice-free and warmer temperatures, to sub-zero and the presence of pan ice. To generalize the area as ice-free is a mistake.
• 2. Freezing temperatures have produced dangerous icing problems to drill ships and semi-submersibles in the lower Cook Inlet. High winds and cold temperatures create these situations.
• 3. The jack up rig George Ferris encountered cold weather that exacerbated mechanical problems in its jacking system, causing it to fail.
This failure caused the jacking mechanism to jam, making it impossible to jack the rig down into the water. Explosives had to be used to blow the jacks off in order to re-float the rig. Subsequent failures ended with the legs being stuck in the mud, necessitating the use of explosives to sever them. The rig was towed out as a hulk.
• 4. Ice build-up on the lattice-constructed legs of the Endeavour has not been addressed. Ice build-up, along with tidal currents, could put stress on the legs.
• 5. The idea of ice of more than 10 percent curtailing drilling operation is laughable. Ice in Cook Inlet can be predicted to a point, however it has surprised many operators.
• 6. If ice develops around the Endeavour and drilling is curtailed, what would be the next step if conditions worsened? When would the well be plugged and abandoned? When would the riser pipe be removed? How severe would the ice have to get before the decision would be made to jack down the rig and move it to an ice-free area?
And how would you tow this rig in ice conditions to an ice-free area without some serious horsepower? With a stated tow speed of four knots in open water, it is imprudent to subject such a rig to tidal currents compounded by ice. I challenge Buccaneer to come up with a rational tow plan in this environment.
• 7. The subject of supplying this rig has not been discussed. Many supply boats operating in the Inlet are of various sizes and horsepower. Most are more than 20 years old and some are not suited for operation in the Inlet during winter months. This rig in particular, with the design of its legs, presents challenges to supply boat operators.
• 8. The subject of oil-spill response has been seriously addressed in the C–Plan, and Cook Inlet Spill Prevention and Response has a track record of fulfilling these requirements. The effectiveness of spill response in ice conditions is open to conjecture. Even with worldwide improvements, response in ice conditions remains questionable.
• 9. Use of dispersants would only make things worse. As in the Gulf of Mexico and Deep Water Horizon Spill, massive use of dispersants is disastrous to the biomass on the sea floor. Damage to fish and animals in the water column is still in dispute, however the environment looks to have suffered substantial degradation.
Mechanical oil recovery in the Inlet is a tough prospect, as tides and currents, compounded by strong winds, puts corralling oil spills and recovering them in the low percentage range. Throw ice into the mix, and the job is next to impossible.
• 10. Another CISPRI tool is in-situ burning, which works in warm climates where currents are light and floating debris is not a problem. The Inlet would present multiple problems, as fire boom use would be very difficult due to currents and possible ice. In-situ burning in cold climates has not proven an effective response tool, as the lack of “light ends” make it difficult to keep the spill ignited. Burning also produces massive amounts of air pollution.
• 11. A CISPRI response to multiple spill events in the Inlet could tax their capacity. Having a spill at both ends of the Inlet would mean a smaller response to both events. The response manual indicates CISPRI will use Offshore Supply Vessels to supply platforms in the upper Inlet.
Having OSV take over as oil spill recovery vessels in various areas of the Inlet could jeopardize the true mission of these vessels, which is to be a safety and support vessel for existing platforms. In the event of severe ice conditions, the time it would take to gear up and transit to a site would also be greatly extended.
• 12. I question weather and ice predictions for the Cosmopolitan Prospect.
Winter winds come from all directions, with speeds in excess of 50 knots. Spill trajectory for the site in winter does not take variable weather conditions into account.
• 13. Buccaneer rig information indicates the Endeavour is constructed to operate to -10 degree Celsius. (14 degrees Fahrenheit.) If this is the case, this rig should not drill in Alaska during the winter at all.
• 14. There is no reciprocal agreement with Furie Oil and Spartan to provide the Spartan 151 jack up rig to drill a relief well in the event of a blowout. In addition, the Spartan 151 is not rated for work in ice.
• 15. Capping an out-of-control well on land may be an easy and fast fix. It may be very difficult on a jack up rig, as capping would have to take place on the sea floor. If the riser is damaged and leaking, a cap may be of no use. There are numerous accounts of blowouts on jack up rigs that resulted in collapse and total destruction of the rig.
Having first worked in Cook Inlet in the ‘60s, the first thing I noticed about the new explorers is that they do not sandbag the spud cans when the rig is jacked up. This was done to prevent bottom scouring around the legs in the past.
It is true that the rig can maintain a level attitude using individual leg elevation, however close inspection is needed to be sure there is not a developing bottom problem. Remote-operated vehicles can do this in today’s high technology world. I have seen no provision covering this problem.
When exploration work first started in the Inlet, equipment that showed up was old in some cases. Western Offshore Drilling and Exploration used a converted barge anchored to the bottom. This barge experienced its first blowout in 1962, which continued through the winter.
Past lessons should be used to guide the State in the future. Decisions can’t be made for financial gain, they must be made on responsible, safe operation plans.
“Best Available Technology” is the world standard. It’s what the State of Alaska demands on the North Slope and Prince William Sound. Cook Inlet has been left behind on this requirement. Supply boats are old and we do not have a big enough rescue tug to assist a disabled ship.
Taking into consideration the current condition of the Endeavour and the unexplained financial issues of the main players in the Complete Oil Discharge Prevention and Contingency Plan Permit, I feel it would be proper and prudent to revoke the entire permit until Buccaneer comes forth with a complete disclosure of main players, their financial responsibility and their ability to drill in Alaska providing the protection the state demands.
The citizens of the State of Alaska and Cook Inlet Region depend on state agencies to protect our valuable marine environment into perpetuity.

Robert Archibald is Chief Engineer of Motor Vessels, Unlimited.

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Posted by on Jan 2nd, 2013 and filed under Point of View. You can follow any responses to this entry through the RSS 2.0. Both comments and pings are currently closed.

1 Response for “Jack up rigs, winter ice don’t mix”

  1. Amen! says:

    I couldn’t agree more….

    “I feel it would be proper and prudent to revoke the entire permit until Buccaneer comes forth with a complete disclosure of main players, their financial responsibility and their ability to drill in Alaska providing the protection the state demands.”

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