Amammoth week of negotiations culminated in Opec’s sparring members effectively agreeing to release an extra 500,000 b/d onto global markets on 22 June. Individual country allocations have been replaced by a group-wide ceiling that will permit the stronger members to capitalize on falling output from the weaker countries.

Always a two-tier organization, the differences between Opec’s haves and have nots is growing.

Nevertheless, Opec Secretary General Mohammad Barkindo appeared...