With oil down more than 20% from its record high, Canadian energy stocks have been beaten down to more affordable levels. But as concerns over demand and refining margins grow, it can be hard to determine which Canadian energy stocks are still viable profit plays.

Strong oil exports helped to boost Canada’s trade surplus in June. The trade surplus increased to $5.4 billion (C$5.8 billion) from $4.8 billion (C$5.2 billion) in May, the national statistics office announced earlier this week. But a large part of that increase was due to higher prices, not higher volumes. Oil reached a record of $147 per barrel on July 11. Since then, oil has dropped to below $115 a barrel.

The drop in oil prices coupled…