The giant Kashagan oil field in Kazakhstan hit a record-high oil production of 400,000 bpd on Tuesday, a few weeks after returning from planned maintenance, three sources familiar with the field’s production data told Reuters on Wednesday. Before the month-long halt due to maintenance, the Kashagan oil field was pumping between 330,000 bpd and 340,000 bpd. Planned maintenance at Kashagan began on April 14 and ended on May 19, ten days ahead of schedule, Kazakhstan’s energy ministry said in a statement on May 20, adding that on the first…