WELL, YEAH: IEA expects U.S. shale output rise if OPEC pushes oil to $60.

Some frackers can make money at sub-$50 prices. Many more are profitable at $60, and working furiously on becoming even more efficient and productive.

Barring a major crisis in the Middle East, there’s an effective $60-$70 ceiling on the price of oil — and that ceiling drops a little with each new productivity gain made by American frackers.