Enbridge Inc. was taken by surprise Thursday by comments PetroChina International, its major partner in an ambitious Alberta to British Columbia pipeline, was pulling out of the $3-billion project.

At an oilsands conference in Calgary, Yiwu Song, vice-president of China National Petroleum Corp., PetroChina's parent company, told media the company was tired of the lack of government and producer support for their business, and was dropping the project.

"We have not discussed CNPC's comments with them," said spokesman Glenn Herchak. "so it would not be appropriate to comment."

The withdrawal of China, which had tentatively committed to 50 per cent of the pipeline's capacity, could spell the end of the already endangered project.

The proposed Gateway pipeline was designed to ship about 400,000 barrels per day of crude from Alberta's oil sands to Asian markets and California via a new marine terminal in Kitimat, B.C.

Enbridge announced last November it was slowing the pace of the project to focus on its more advanced Alberta Clipper pipeline project to markets in eastern Canada and the U.S. Midwest.

The Alberta Clipper would eventually reach the Gulf Coast and the large number of refineries in the region, a crucial component for Canadian producers to access oil-hungry U.S. markets.

According to Enbridge, details on the memorandum of understanding signed with PetroChina on Gateway were confidential. But reports indicate the state-run corporation had committed to half the crude throughput on the line.

Herchak said other potential customers still are interested in Gateway, and the company is keeping to a 2012/2014 start-up date.

"While China could be a market for Gateway production, Asia Pacific and California are also potential markets," he said.

Enbridge currently is in discussion with oilsands producers, refiners in California and offshore, as well as potential customers in Japan and Korea, Herchak said.