The all-stock deal is worth about C$1.1 billion ($910 million). : (Bloomberg) -- Tourmaline Oil Corp. agreed to acquire rival Black Swan Energy Ltd. for about C$1.1 billion ($910 million) as Canada’s largest natural-gas explorer eyes future exports of the heating and power plant fuel from the country’s west coast. The purchase of closely held Black Swan will give Tourmaline gas production of as much as 2.3 billion cubic feet per day by mid-2022, Tourmaline said Friday in a statement.