|
Shell fleet continues to mobilize; impact of vessel damage unclear
Some of the vessels participating in Shell’s Chukchi Sea exploration drilling project have departed Dutch Harbor for the drilling area, Shell spokesman Luke Miller told Petroleum News in a July 6 email. But the semi-submersible drilling rig, the Transocean Polar Pioneer, remains in Dutch Harbor for the time being, and the drilling vessel Noble Discoverer is still in transit from the U.S. West Coast to Dutch Harbor, Miller said.
Shell has said that it hopes to start drilling in the third week of July, but the timing will depend on how quickly the winter sea ice retreats from the drilling locations.
The drilling project has encountered a problem in that, on July 3, the crew of the ice management vessel, the MV Fennica, discovered a leak in the vessel’s ballast tank after the vessel had headed north from Dutch Harbor.
“The vessel returned to Dutch Harbor where, upon inspection, a small breach of her hull was discovered. All appropriate authorities were promptly notified and repair options are being considered,” Miller said in a July 7 email.
According to media reports, the Fennica may have struck an uncharted undersea obstacle after leaving Dutch Harbor. Apparently, the vessel had been operating under the guidance of a certified marine pilot.
The Fennica carries Shell’s well capping stack, a piece of equipment designed to plug onto the top of a well and seal the wellhead, should a well blowout happen and the well’s blowout preventer fail to stop an uncontrolled flow of oil. Shell cannot drill into a potential hydrocarbon bearing zone without having the capping stack staged at an appropriate location.
Shell says it does not know what the impact of the damage to the Fennica will be on the company’s drilling plans.
“At this point we do not anticipate any impact on the season but it’s too early to know for sure,” Miller said. “Any impact to our season will ultimately depend on the extent of the repairs.”
Two wells planned Shell wants to drill two wells this year in the Burger prospect, about 70 miles northwest of the Chukchi coastal village of Wainwright. The prospect is a dome-shaped geologic structure, about 25 miles in diameter and known to contain a major natural gas resource. Shell is betting on finding oil under the gas.
Although the company will have two drilling rigs available for the drilling of the two planned wells, the U.S. Fish and Wildlife Service, in the interests of minimizing disturbance to walrus, has prohibited simultaneous exploration activities by drilling rigs within 15 miles of each other. Although Shell has staked out six possible Chukchi well locations, none of these locations appear to lie more than 15 miles apart.
The impact on Shell’s plans of this distance limitation has yet to become clear. The Bureau of Safety and Environmental Enforcement requires sufficient time within the summer Arctic open water season to drill a relief well, should a well blowout occur during a planned drilling operation. A relief well plugs an out-of-control well with cement. This relief well requirement significantly limits the time available during the open water season to drill planned wells. According to Shell’s exploration plan, an average drilling season length would be sufficient to sequentially complete one well and partially drill a second.
- ALAN BAILEY
| 