also this from oil-price.net29 May 2013"Obviously, drilling for...

also this from oil-price.net
29 May 2013

"Obviously, drilling for oil is pricey. Expensive labor, swelling cost of inputs like diesel fuel, chemicals and steel have all, in various degrees, increased the cost of exploration and production. The supplies from unconventional sources are also expensive. Furthermore, with stringent environmental norms in place, oil companies are forced to shell out more to keep their licenses.According to a research report published last year by Bernstein Research the cost of production in the most expensive (marginal cost of supply) new field has shot up to $92 per barrel, quickly nearing $ 100 per barrel- excusing OPEC and former Soviet Union. In simple economic terms, higher oil prices lure the companies to spend humongous resources on exploration and drilling. If the prices fall below a certain range, it becomes unviable for oil companies to spend energy on future explorations...."

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http://www.oil-price.net/en/articles/lower-bound-of-oil-prices.php