Proved reserves at Eni’s flagship Zohr gas field in the Egyptian Mediterranean deepwater fell to 3.38tcf at end-2018 from 4.00tcf a year earlier, according to figures in BP’s 2018 annual report. This is a substantially larger fall than is accounted for by the field’s 2018 production which averaged 1.18bn cfd for a total of just over 430bcf.

BP has 10% of Zohr in its own right as well as 19.75% of Russian state firm Rosneft which has a further 30% of Zohr. BP says its...