No, it was processed Iranian and Iraqi oil that filled the oil tanks in Alexandria that the RN used.
Iraqi production in the early 1940s was in the north around Mosul and Kirkuk - but the pipelines for the oil went to Tripoli in the French controlled Levant (modern Lebanon) and Haifa in British controlled Palestine (modern Israel). So there's a lot of ground to capture to get to the wells plus the associated pipelines - and then the non-existent Axis tankers have to get from the ports in the Middle East back to Europe past the RN.
Re "non-existent tankers"...
FWIW the Italian Merchant Marine included 82 tankers with a displacement greater than 1,600 tons, gross in 1939 with a total displacement of 427,000 tons, gross and 613,000 deadweight tons. The source for this is Appendix VII of the British official history on merchant shipping and the demands of war.
Unfortunately, I don't have any information handy on the number of Italian tankers that were in the Mediterranean and Black Sea when Italy joined the war.
During the war Italy got most of its oil from Romania and it came by sea via the Black and Aegean Seas. The distances from Brindisi to Constanta, Romania; Haifa, Palestine; and Tripoli, Lebanon are about the same, i.e.
- 1,200 nautical miles Brindisi to Tripoli, Lebanon.
- 1,243 nautical miles Brindisi to Haifa.
- 1,304 nautical miles Brindisi to Constanta.
All the passages take 5-6 days at 10 knots. So they can't transport any more oil from the Levant to Italy than they were able to from Romania (and in spite of what I'm about to write that's the safer route) and all we can reasonably say is that if the Italians can take some oil from Iraq there's more Romanian oil for the Germans.
Source:
http://ports.com/sea-route/
Yes, the tankers will have to get past the British Mediterranean Fleet, but it's likely that the tankers will have a strong escort. The Regia Marina will have enough fuel to put all its operational battleships to sea at the same time.
I do know (from the British history of the war in the Mediterranean and Middle East) that the oil refineries at Haifa were in "shore bombardment" range and the same could also apply to the oil refineries at Tripoli. Therefore, bombarding the ports and refineries instead of attacking the convoys might be a better tactic.
It's also about 300 miles by air from the Nile Delta to Haifa and 400 miles from the Nile Delta to Tripoli which means that both ports were within bombing range. (Source:
https://www.distancefromto.net/) However, IOTL the RAF only had a few squadrons of Wellingtons in the Middle East in 1940-41 IOTL. Is that enough to do significant damage to the refineries and ports? OTOH if they're spending most of their time bombing Haifa and Tripoli ITTL they're not bombing that targets they attacked IOTL.
I was going to write that that the tankers and their escort would have support from aircraft based in the Dodecanese Islands and southern Turkey. However, when I looked at the map I also saw that Cyprus was slap bang in the middle of the route from Haifa and Tripoli to Italy and less than 200 miles away from those ports. So it's perfectly placed to act as an air base to attack the ports and the tankers.
However, AFAIK it didn't have any military airfields in June 1940 and IIRC the British garrison in June 1940 consisted of one infantry company. It will need to be more heavily defended ITTL which will divert resources that were used elsewhere in the theatre IOTL. Similarly, the resources needed to develop the air bases will have to come from elsewhere in Mediterranean and Middle East theatre.