The noise of helicopters has become a familiar sound between Kasilof and Cannery Loop, where Unocal has hired Fairweather Geophysical LLC to search for new pockets of natural gas.
Fairweather started seismic work about a month ago in the area between Kalifornsky Beach Road and the Sterling Highway, said Unocal spokesperson Roxanne Sinz. Workers plan to finish there this week, then move to sites around the Swanson River oil field north of Sterling. Unocal has budgeted about $1 million for work in both areas, Sinz said.
If the seismic work detects promising geologic formations, Unocal will drill exploratory wells in 2001, she said. Before drilling, though, it will have to hold public hearings and obtain new permits.
During seismic testing, workers use explosives or heavy hydraulic equipment to generate the vibrations used to map underground geologic formations. Between K-Beach Road and the Sterling Highway, Sinz said, the goal is to find new pockets of gas associated with the Kenai Gas Field.
Sinz said the Kenai gas is essentially a bubble trapped under a dome-shaped formation. Unocal hopes the seismic work will reveal ridges along the slope of the dome that may hold additional pockets of gas.
Workers on snowshoes have been setting dynamite charges about 20 feet underground along about 25 miles of seismic lines between the Sterling Highway and K-Beach Road. They have been using helicopters to move the portable rig used to drill holes for the dynamite.
"We're using helicopters so that we don't have much impact to the surface," Sinz said.
Seismic workers sometimes use tracked vehicles to haul drilling rigs, or skip the dynamite and use heavy vehicles with hydraulic equipment to generate underground vibrations. How-ever, moving heavy equipment through the woods means clearing trees and cutting the seismic trails well-known to snowmachiners and skiers. To avoid that sort of impact, seismic crews now often use portable rigs that can be moved with small ATVs or helicopters.
"Before, we basically had to clear a road," Sinz said. "Now, doing it this way, no trees are cut, and there is virtually no impact to the surface."
The seismic project is 100 percent Unocal's, Sinz said, but Marathon Oil Co. operates the Kenai and Cannery Loop gas fields. If Unocal makes a significant find, she said, it will have to work with Marathon to develop it.
Land between K-Beach Road and the Sterling Highway is a mix of Native corporation, state, Kenai Peninsula Borough and privately owned parcels. Areas Unocal plans to explore near the Swanson River oil field lie within the Kenai National Wildlife Refuge.
"On the refuge, we're not in the business of destroying surface vegetation," said Jim Frates, refuge operations specialist. "That's why we've gone largely to helicopters."
Frates said Unocal plans to start work next week on nine miles of seismic line east of its Swanson River field. The work area lies roughly between Fish Lake, near Swanson River Road, and Crane Lake, near Captain Cook State Recreation Area.
The contractor will use helicopters to move the drilling rig, Sinz said.
Unocal also has requested permits to work on 14 miles of seismic lines west of the Swanson River oil field, roughly from Marathon's Beaver Creek Oil and Gas Field to Stormy Lake near Captain Cook State Recreation Area.
The U.S. Department of Fish and Wildlife, which oversees refuge land, has not yet authorized that project.
"We have some concerns," Frates said. "It's been a tough winter for moose. That's some of our better wintering area."
Frates said Fish and Wildlife wants to see how many moose are in the area before authorizing the seismic tests.
While oil companies increasingly use the new 3-D seismic technology to find new pockets of oil and gas, Sinz said the present seismic surveys are two-dimensional.
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