TransCanada PipeLines’ preliminary investigations have indicated external corrosion was the likely cause of two ruptures in a 36-inch NOVA line pipeline in northwest Alberta Monday and Tuesday that has closed down about 800 MMcf/d of throughput.

“We have crews working around the clock to repair the pipeline,” says Don Wishart, TransCanada’s executive vice-president, operations and engineering. “We want to get it operating safely and reliably as soon as possible.” The incidents occurred in a fairly remote area and no one was injured in the resulting fires.

The affected sections of pipeline are about 100 kilometers southeast of Grande Prairie, AB. TransCanada’s Alberta employees continue to work with regulators at both sites to investigate and evaluate the damage, the company said in a Thursday update on the situation. About 285 MMcf/d continues to flow through a parallel line to the ruptured pipeline. TransCanada has issued a number of operational orders for surrounding systems on its bulletin board (go to https://www.transcanada.com/Alberta/ and click “critical notices”).

NGI’s sources stressed that this did not mean 800 MMcf/d was knocked off the market. A Calgary-based trader estimated that with re-sourcing and diversions going on, only about 300 MMcf/d of supply was actually being affected. One producer said his company had redirected some of its affected gas onto Alliance Pipeline, and had only shut in about 30 MMcf/d. He commented that the affected Nova pipe was “a pretty old section” of the system. A TransCanada spokesperson said the line, the Western Alberta System Mainline Extension, went into service in 1970, a year after the main NOVA system was operational.

Another producer, ARC Energy Trust said its ARC Resources Ltd. has shut in approximately 25 MMcf/d of production from the Ante Creek area, but it does not expect the temporary shut-in to affect earnings.

TransCanada said it has an extensive integrity program that meets and often exceeds industry standards. The program includes pipeline maintenance, corrosion control, leak detection, aerial patrol, cathodic protection surveys and public awareness. TransCanada has spent approximately $74 million on its pipeline integrity program this year.

©Copyright 2003 Intelligence Press Inc. All rights reserved. The preceding news report may not be republished or redistributed, in whole or in part, in any form, without prior written consent of Intelligence Press, Inc.