As OPEC ministers meet in Vienna this week they’ll be debating whether the strategy that’s upended oil markets is working. The last time the Organization of Petroleum Exporting Countries met, in November, it jolted markets by leaving production unchanged instead of staunching a glut by trimming output. Prices collapsed to the lowest in six years. OPEC said it wanted to “restore market equilibrium” with stable prices. That means flooding the market so oil drops to a level that forces higher-cost producers to scale back, ultimately pushing prices back up. Now the 12-member group, which controls about 40 percent of world supplies, has to decide whether to change course or stick to its target. These charts illustrate to what extent the strategy has been paying off. Producers are cutting back… Data from the Energy Information Administration shows a contraction in monthly production growth from the top three shale producing regions […]