Rystad Energy, an independent oil and gas consulting services and business intelligence data firm in Oslo, Norway, has online, a wealth of information concerning upstream oil production projects and costs. Some of it is a bit dated but some of their charts date from late 2015.
The two below Rystad charts were published by CNN Money on November 23, 2015.
This is overall or average cost, not marginal cost. It cost Canada $41 to produce a barrel of oil but only cost Russia $17.20. I guess that is why Canada is cutting back but Russia is not.