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Results are in: East coastal area open Alaska drafts new criteria for opening North Slope tundra for winter work based on 2003-’04 study; more snow needed in Foothills Kristen Nelson Petroleum News Editor-in-Chief
The Alaska Department of Natural Resources has released results of its study of equipment impacts on tundra at varying depths of snow and ground hardness, and has changed its criteria for when the North Slope will be opened for winter travel, setting ground-hardness measurement standards for the coastal area and for the foothills and increasing the amount of snow required for opening the foothills.
Commissioner of Natural Resources Tom Irwin said “this is a real scientific approach and that’s the way we ought to be doing business.” Irwin, speaking at a Dec. 10 press briefing on the study results, said as a result of the study the east coastal area of the North Slope was being opened for oil and gas exploration. “This opening is the earliest since 1995 and it’s frankly two weeks earlier than last year for this area,” he said.
When the tundra is opened is a cost issue for the industry, and impacts the amount of exploration work that can be done, Irwin said, noting that if you can drill three exploration wells from one ice road “the cost of that road is divided over three wells. If your time is so limited you build a road and can only drill one well,” that well has to bear the entire cost of the ice road.
The cost relates to how early the state opens the tundra to travel so that seismic work can begin and ice roads and ice pads can be built for exploration.
Irwin said the state doesn’t expect to see more money spent on exploration.
“Actually what I think we’ll see is the same amount of money will be spent, but you’ll get more footage of exploration drilling instead of dollars spent on access.”
Irwin said he wanted to make sure that “everyone involved in Alaska” receives “the message that this is done correctly. We’re not taking any shortcuts; we’re not sacrificing the environment at all.” Testing on coastal plain and in foothills The state tested the effects of equipment on the tundra at plots south of Deadhorse on the coastal plain and at plots in the foothills. Different types of equipment used on the tundra were driven over the plots at intervals from late October to late January, and the results were measured at the test plots over the summer. Data was then run through a model developed for the program, and it is those results that have just become available.
Bob Loeffler, director of the Department of Natural Resources’ Division of Mining, Land and Water, said the oil exploration season on the North Slope “has been shortened by half” since the 1970s, shrinking from 208 days in the early 1970s to just more than 100 days. The goal of the study, he said, was to see if there was a way to increase winter on-tundra work time, “without consequences to the environment. I am very pleased that I think that we’ve found a way to do that,” Loeffler said.
The study that the division did, he said, involved driving a range of equipment over plots “from essentially Halloween, when we knew the ground to be soft, to the … latter part of January, when we knew the ground to be very hard.”
The expectation, he said, was that impacts would be much greater in the fall than in the winter. What the division found, Loeffler said, “was far less impact than we suspected at any of the treatment dates.” There were essentially no ruts, even from the October tests, he said, a result the division is attributing to snow cover in October. State partnered with DOE, Yale The study was a collaborative effort, said Harry Bader, northern region land manager for the Division of Mining, Land and Water, who headed up the study. The U.S. Department of Energy provided a quarter of a million dollars toward the project, he said, and the Yale University School of Forestry “gave unstinting time in terms of their faculty and their research facilities in New Haven, Connecticut.”
The Alaska Support Industry Alliance and the Alaska Oil and Gas Association also contributed support, as did the University of Alaska Fairbanks. “Our study was carried out on the back of graduate students and interns,” Bader said.
Bader said the division learned a number of things from the study, first “that snow depth, the density and the hardness of the snow — which we call snow slab — and ground hardness, all interact to create a resistance on the part of the tundra” to the types of activities associated with winter oil and gas exploration.
Among those variables, he said, snow is very important, and “not just snow, but the character of the snow.”
The model the division used is driven more by “snow slab thickness, the hardness of the slab layer,” than by “any other one variable,” Bader said. “We also found that ground hardness, which is an important contributor to tundra resistance to damage, actually reaches a certain level after which it no longer contributes to greater resistance to damage.”
And, “in every case, as Bob (Loeffler) said, the damage was less than we anticipated. And in part that was because we had sufficient snow: snow protects,” he said.
“So what are the implications of this? Simply we can increase the winter work season without increasing environmental damage.” New criteria The new criteria, Bader said, require more snow cover (nine inches rather than six inches) in the foothills, a woody tussock tundra environment. The ground hardness for foothills opening has been defined as 25 drops of the drop hammer, “which is something that the North Slope team invented, which is a very effective tool for measuring hardness,” he said.
On the coastal plain, which has a wet/moist sedge tundra environment, more resistant to damage, he said: “We’re keeping the old six-inch snow standard and we’re setting the effectiveness at 75 drops of the slide hammer.”
The hammer drives a probe into the frozen earth, and the number of drops is a measure of ground harness.
Bader said the division is “going to continue to monitor, verify and improve.”
Division staff will accompany seismic crews into the field this winter, he said, “to see if the level of environmental disturbance that we anticipate from our model, the study, actually materializes out on the tundra.”
And the division will monitor the research plots “to see if there is any lag-time effect of a disturbance that we did not see after one season, to see if it materializes after two seasons.” Approach has been cautionary Irwin said that based on the study results, the department is “still on the conservative side” of when to open the tundra. “We could be criticized for not opening soon enough in the past years,” he said.
But Bader argued that in the past the department “has appropriately adopted a precautionary principle, and that is, we open the tundra in the most conservative fashion possible, because there wasn’t sufficient information that was available to our staff. So our staff adopted precisely the correct policy, which is in the absence of information you always adopt the precautionary principle, and that is, you become conservative.”
The department said in its project report (available online at http://www.dnr.state.ak.us/mlw/tundra/) that it began reforming the way it did tundra travel management in 2002, first by standardizing measurement techniques.
The department “created 30 permanent measurement stations in 2002,” to serve as the locations for measuring snow depth and ground hardness. Ten of the measurement stations are along the Dalton Highway at about 10-mile intervals from Deadhorse to Slope Mountain and the other 20 are distributed within the North Slope oil field complex spanning approximately 40 miles across the slope.
The department also divided the North Slope into four geographic tundra opening areas (upper foothills, lower foothills, east coastal and west coastal).
The slide hammer probe, used to measure ground hardness, was also redesigned to remove variability in measurement from operator to operator. “It is now a true ‘drop’ hammer with standard drop weight and drop distance, employing no assistance from the operator,” the department said. This new drop hammer was tested in the field in January 2003 “and calibrated to assist with comparison to prior data sets.”
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