Oilfield service giants Schlumberger, Halliburton and Baker Hughes are all proclaiming the industry crisis that has lasted since the mid-2014 collapse of oil prices is ending. But with Brent prices falling to the lowest level since 18 April this week, the recent oil price recovery is far from assured to last.

Number one service firm Schlumberger recorded its first increase in total revenue since Q3 14, but this was solely due to the inclusion of revenues from acquired Cameron International...