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Hilcorp, Eni have 5-year ice road plans
Companies apply to National Marine Fisheries Service for incidental take of small numbers of mammals from ice road construction Kristen Nelson Petroleum News
The National Marine Fisheries Service has received a request from Hilcorp Alaska LLC and Eni US Operating Co. Inc. for authorizations to take small numbers of marine mammals incidental to ice road and ice trail construction, maintenance and operation on the North Slope for a five-year period, 2020-25.
NMFS said it is proposing regulations to govern that take and requests comments through Feb. 18.
The proposed activity involves the Northstar Production Facility, the Spy Island Drill Site in the Nikaitchuq unit and the Oooguruk Drill Site in the Oooguruk unit, all in the Beaufort Sea off Alaska’s North Slope.
Hilcorp constructs annual ice roads and trails during the ice-covered season to connect West Dock and Northstar. Eni builds and uses an ice road connecting the Oliktok Production Pad and the Spy Island Drill Site, SID, and also builds an annual ice road from shore to the Oooguruk Drill Site.
NMFS said both companies generally begin construction of sea ice roads and ice trails as early as possible, usually by late December. Maintenance and use of the ice roads and trails continue until the ice becomes too unstable to access, generally in mid-May.
Depending on the weather, from initial surveying until the ice is thick enough to allow wheeled vehicle travel is roughly six weeks.
Northstar, an artificial gravel island, is in state waters some 6 miles offshore Point Storkersen at a water depth of about 12 feet. NMFS said the region is covered by landfast ice in winter with water depths greater than 10 feet.
SID is also an artificial gravel island constructed in state waters in some 6-8 feet of water; it is some 3 miles north of Oliktok Point and just south of the Spy Island barrier island.
Northstar ice roads, trails The ice road from West Dock to Northstar is some 7.3 miles; it is used to transport personnel, equipment, materials and supplies, allowing use of standard vehicles such as pick-up trucks, SUVs, buses and other trucks.
“In some years depending on operational needs and weather conditions, Hilcorp may elect to not build the main improved ice road,” relying instead on an ice trail that can support only tracked, lighter-weight vehicles, but NMFS said that to cover all scenarios Hilcorp is assuming that an ice road would be built each year for the next five years.
In water deeper than 10 feet ice must be some 8 feet thick to support construction equipment. Ice road construction activities occur 24 hours a day, seven days a week during construction, and are only halted in unsafe weather conditions such as high winds or extreme low temperature.
Steps to build the Norstar ice road include:
*Clear snow with tracked vehicles.
*Grade or drag ice to smooth surface, incorporating rubble ice or moving it off road surface.
*Drill holes through floating ice using rolligons equipped with ice augers and pumps.
*Pump seawater over floating ice.
*Flood the ice road.
NMFS said ice trails are unimproved access corridors used by Tuckers, snowmobiles and other tracked vehicles.
Hilcorp usually builds unimproved ice trails along the pipeline corridor from the valve pad near the Dew Line site to Northstar; from West Dock to the pipeline shore crossing; and from the hovercraft tent at Dockhead 2.
Eni — Nikaitchuq, Oooguruk NMFS said each year Eni builds an ice road and three ice pads, the ice road 4.2 miles from Oliktok Production Pad to SID in the Nikaitchuq unit, with both supported on water and grounded sections. The company also typically builds two floating ice pad parking areas at SID and one grounded ice pad at the Oliktok Point end of the ice road.
Floating sections of the ice road are constructed using pressure pumps to flood the ice surface with seawater with small rolligon vehicles with augers and pumps used for augering and flooding.
NMFS said rig mats are used to bridge small leads and wet cracks during construction and maintenance.
Eni plans to build an unimproved ice trail just west of and parallel to the sea ice road corridor near SID for use when the ice road is being constructed. It is not used after the ice road is open to regular traffic, but several shorter length trails may be needed after March 1 to work around unstable and unsafe areas of the ice road as the season progresses.
Eni requires a single ice road and staging area ice pad each year to operate the Oooguruk Drill Site. That ice road runs 5.5 miles, with an alternate 7-mile route used in years when an early road completion is required or an extra heavy load, such as a drilling rig, is expected. The ODS is in 4 to 6 feet of water and the area from the site to shore generally becomes grounded landfast ice in winter, NMFS said.
While ODS operations do not require offshore ice trails, a coastal trail in very shallow water right off the beach between Oliktok and the ODS ice road is sometimes needed to demobilize equipment after tundra travel has been closed.
Mitigation measures There are extensive mitigation measures, including avoidance of ringed seal structures by a minimum of 150 feet during ice testing and new trail construction. If a seal is observed on ice within 150 feet of the centerline of the ice road, construction, maintenance or decommissioning activities must not occur, “but may proceed as soon as the ringed seal, of its own accord, moves farther than 150 ft distance away from the activities or has not been observed within the areas for at least 24 hours.” NMFS said requirements are different for transport vehicles, those not associated with construction, maintenance or decommissioning, which may continue their route within the designated road/trail without stopping when a seal is observed within 150 feet.
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