PetroChina, Asia's largest oil and gas company, is buying the 40 percent interest it didn't own in the MacKay River oil sands project in Canada for US$673 million.
The deal with Athabasca Oil Sands Corp., announced Tuesday, gives PetroChina full ownership in one of the newest of northern Alberta's oil sands developments. Athabasca had sold PetroChina a 60 percent stake in the project last year.
China's state-owned oil companies have invested billions of dollars in exploration or production ventures in Canada, Africa, Latin America and elsewhere.
Industry officials estimate Alberta could yield as much as 175 billion barrels of oil, which would make Canada third only to Saudi Arabia and Venezuela in crude oil reserves.