July 8, 2009

Environmental Engineering

British Columbia pipelines to be rerouted under the Salmon River using horizontal drilling

Jim Stirling

correspondent

Prince George

Rather than taking chances with the unpredictable power of nature, some pipelines are going deep underground.

A construction project in central British Columbia will re-route an oil and two natural gas pipelines beneath the unpredictable meanderings of the Salmon River.

Horizontal drilling techniques will be employed to safely replace sections of the pipelines, about 20 metres below the river’s flood plain.

Work will be tendered for construction this summer and substantial completion is scheduled for November.

No cost estimate was available.

“We’ve been looking at our options to best manage the river and the pipeline facilities,” explained Steve Henderson, manager of community and aboriginal affairs for Spectra Energy Transmission based in Prince George.

“The best long-term solution is to separate the river from the pipelines by drilling for about 700 metres under the entire flood plain and replacing the three lines.”

The company operates more than 5,500 kilometres of pipeline facilities in B.C. and Alberta.

It also runs major processing plants where sour gas, gathered primarily from wells in northeastern B.C., has impurities such as carbon dioxide, hydrogen sulphide and water removed before delivering the natural gas to customers.

The Salmon River is a tributary of the Fraser River and Spectra’s pipeline right-of-ways intercept it about 24 kilometres north of Prince George.

A 76 centimetre diameter natural gas pipeline was built in 1957 and a 91 centimetre line added in the mid-1990s.

The 30 centimetre diameter oil pipeline – now owned by Pembina Pipeline Corp. – was installed in about 1962.

Since then, nature’s taken its course.

“There’s lots of energy in the river and it wants to go in different ways,” said Henderson.

Drill and intersect technology will be used from both the north and south sides of the river’s flood plain.

“We will string the new sections of the pipeline out on the ground and do the welding, cutting and hydrotesting,” he explained.

The newly constructed sections will be fed through a guide hole, tied to the existing lines and the old sections removed.

“Part of our consultations with local residents and agencies like the Department of Fisheries and Oceans and the provincial Ministry of Environment was to develop the best approach to better manage the project,” continued Henderson.

That includes the installation of a temporary bridge.

“It will allow us to avoid the river. There will be very limited, if any, activity in the river itself,” he predicted.

Plans call for removal of the temporary bridge next spring, when the site dries out after snow melt.

“One of the things that’s important with this project is that Spectra Energy is very diligent in consulting with everyone, including aboriginals,” said Henderson.

Print | Email | Comment