The Alliance natural gas pipeline in Canada returned to service by early Oct. 20, according to Thomson Reuters data.

The pipeline shut on Oct. 12 for what was supposed to be seven days of maintenance to install new pipe sections at two places in western Canada where a highway will cross the mainline.

In the 30 days prior to the Oct. 12 outage, Canada exported about 1.7 billion cubic feet per day of gas to the U.S. on the Alliance pipeline, Reuters data showed.

Alliance Pipeline LP is sponsored by affiliates of Enbridge Income Fund and Veresen Inc.

It is one of the most important liquids-rich natural gas conduits between western Canada's Montney region and the Chicago market hub.