The refusal of Saudi Arabia and its OPEC allies to curb crude oil output in the face of plummeting prices has set the energy world on a painful course that will leave the weakest behind, from governments to U.S. wildcatters. A grand experiment has begun, one in which the cartel of producing nations — sometimes called the central bank of oil — is leaving the market to decide who is strongest and how to cut as much as 2 million barrels a day of surplus supply. Oil patch executives including billionaire Harold Hamm have vowed to drill on, asserting they can profit well below $70 a barrel, with output unlikely to fall for at least a year. Marginal producers in less profitable U.S. shale areas, as well as countries from Iran to Russia and operations from Canada to Norway will see the knife sooner, according to analyses by Wells […]