WALHALLA, N.D. When Larry Kotchman first learned of plans to build a crude oil pipeline through Cavalier and Pembina counties, his first thought was the need to protect a valuable and environmentally sensitive area the Pembina Gorge and Tetrault Woods State Forest.
"We were concerned that anything that would be done wouldn't have an effect on the forest," said Kotchman, a North Dakota state forester. "We have to protect that resource."
The North Dakota State Forest Service acquired the 432 acres of Pembina Gorge land in 1970 that now is Tetrault Woods State Forest. So, in May 2006, the Forest Service started to negotiate with representatives of TransCanada Keystone Pipeline.
"We made it clear early on that we wanted this horizontal, directional drilling," Kotchman said. "The important thing is, before this was even in the media, we quietly worked this out, to benefit North Dakota and to protect the forestland.
"We're pleased that the Keystone folks are moving in this direction."
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Kotchman said the proposed site of the river crossing essentially is the same area as the Pembilier Dam site that was proposed several years ago.
"It's attractive. It's the narrowest area of the valley, so you can cross the valley fairly quickly," he said.
Horizontal drilling
Horizontal, directional drilling technology evolved from the oil industry in the early 1980s, according to L.A. "Buster" Gray, TransCanada Keystone Pipeline project director.
In this case, it involves setting up a drill rig on one side the south side of the Pembina River.
A small, 4- to 6-inch-diameter pilot hole is drilled at an inclined angle, 25 to 30 feet below the surface of the ground and river. The drill contains a guidance system similar to a GPS navigational system that monitors and corrects the course as it proceeds to the north side of the river.
It may take three or four passes, widening the hole each time, until it is 38 to 42 inches in diameter. Other steps may be taken to ensure that the hole is solid, with no obstructions, Gray said.
"These tools have become extremely accurate over the years," Gray said. "When the first technology came out in the early 1980s, we used to say, 'we're just glad it came up on the other side.' Now, if you put a stake in the other side, the driller is almost upset if it the drill doesn't hit it."
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Once it is completed, the sections of 30-inch pipe is hooked to the drill head and pulled on rollers through the hole, under the river, to the other side a distance of 3,410 feet.
Bentonite clay is used to fill the hole around the pipeline.
Gray said horizontal drilling is commonly used, on a much smaller scale by city utility departments, to pull utility lines under streets and sidewalks.
He anticipates a crew of 10 to 15 workers will be involved in making the hole to feed the pipe under the Pembina Gorge. Because it is such a specialized field, those workers likely will be brought in from out of the area.
Assembly-line crews
Outside of the horizontal drilling area, the pipeline construction operation will involve a much larger workforce.
"The key item is they're not all working at the same place at the same time," Gray said.
The largest crew would be 50 to 60 people, with smaller crews of 20 to 30, or 14 to 15 people that may be staggered along the pipeline right of way.
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Cavalier and Pembina counties might have four crews, with an average of 100 workers.
The pipeline construction resembles a 50-mile-long assembly line that moves about 1.25 mile per day. Each crew moves 1.25 miles per day.
"If you start at the Canadian border, the last one doesn't start until the first one is almost 50 miles away," Gray said. "You kick off one crew. Then, maybe 3 or 4 days later, you start the next crew. You get some flavor for the duration you'd be in the county."
After construction is completed, crews will continue to do hydrostatic testing, filling the pipe with water and conducting a final quality test. That means affected landowners probably will see crews longer than the six-month construction period.
Why not
everywhere?
The Keystone Pipeline will be buried 4 feet underground through most of its 2,848-mile route from Hardisty, Alta., to Illinois and Oklahoma. Conventional construction requires digging trenches in which to place the pipeline.
TransCanada considers a variety of factors in determining whether to use conventional or horizontal drilling methods of building a pipeline. Cost and feasibility are key, according to Gray.
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"In our industry, we have typically used these techniques for very large rivers and streams like the Missouri River, scenic areas and environmentally sensitive areas," Gray said.
It currently costs about $100 per foot to dig and build a conventional 30-inch pipeline, buried 4 feet underground.
The cost of horizontal, directional drilling is about $500 a foot.
Another factor is whether it is even feasible. Sometimes, the soil conditions do not permit the horizontal drilling method.
The North Dakota Public Service Commission and the state Department of Health have requested that TransCanada use horizontal, directional drilling to cross the Sheyenne River near Fort Ransom State Park, too.
"We're doing the geotechnical work at the river, to assess whether the work can be done that way. If it turns out that we can, we would do it," Gray said.
He estimates it will cost about $500 million to build the pipeline through North Dakota. That is $200 million more than initial estimates, which were done in 2005.
Reach Bonham at (701) 780-1269 or kbonham@gfherald.com .
