Can falling tight oil opex save marginal plays?

Focused tight oil operators have recently drawn attention to how field operating costs have fallen by 20-30%. Per unit opex is virtually always lower than capex, so how important is it to mange this expense in a low price world? Our models indicate that further reducing US tight oil opex in a US$30/bbl price environment can help support margins in a few NPV positive plays. But for those assets out of the money, additional opex reductions will not be enough to transform the assets into economic projects.