Like invasions of Russia and land battles in Asia, a war on U.S. shale promises to be a protracted and unpredictable campaign. Rising U.S. shale oil output is one target of Saudi Arabia’s push to have OPEC members maintain their output and so depress oil prices . Even leaving aside OPEC’s clutch of internal divisions, though, fighting U.S. shale will prove a grind —with substantial attrition on the cartel’s side. Part of OPEC’s problem is that U.S. shale is a many-headed beast, with multiple resource basins and operators. So there isn’t a single price below which production gets shut down. Rather, estimates of break-even prices in U.S. shale span a range: Citigroup , for one, estimates this to be around $70 to $90 a barrel using full-cycle costs. “Full-cycle costs” is the crucial phrase, as it incorporates big up front charges such as acquiring land. In core shale […]