Oil Slides on Surprise Increase in U.S. Inventories Russia boosted oil production to levels not seen since it joined OPEC in a coordinated output cut, helping the group offset supply disruptions elsewhere. The world’s biggest energy exporter raised production last month to 11.215 million barrels a day, a jump of 148,000 barrels from a month earlier and just below the post-Soviet record set in October 2016, according to government data emailed Thursday. The country is currently forecasting output will remain at these levels in the next five months, a government official said, asking not to be named as the information isn’t public yet.