Across oil fields from Texas to North Dakota fears are growing that crude’s plunge below $30 a barrel is more than just another market milestone and marks a countdown to an endgame for many shale producers that so far have braved the 18-month downturn. Oil prices tumbled by more than a fifth this month to 12-year lows 70 percent below mid-2014 levels and traders brace for more declines as world production keeps outpacing demand. Yet many of around 50 listed U.S. independent oil producers and scores of smaller ones need $40-$60 a barrel to break even, according to several analyst. A longer spell of $30 oil will confront them with stark choices: bankruptcy, debt writedowns in return for deep concessions to creditors or fire sales of assets at a time when potential buyers are skittish. “There’s no […]