What might have been?
"The growth of the Libyan oil industry dates from 1951 and the coming of national independence. There had been surveys of a small scale and technologically limited kind in Libya in the Italian period. Some shows of oil had been discovered in Tripolitania as early as 1914 when water wells were drilled to supply Tripoli city (Waddams 1980, 27). Other oil was discovered in Tripolitania in the 1930s and a full scale exploration programme was prepared in the years 1937–1940 by the Italian national oil corporation under the geological guidance of Professor Ardito Desio, but never fully implemented due to the onset of war. Indeed, Desio was to return as a consultant to the oil companies working in Libya in the 1950s."
Libya's Oil Resources - Volume 20
So the problem isn't so much the discovery as
a. The inability to exploit it with the inexperienced Italian oil industry (how to get it out of deep wells) and
b. If, in the unlikely event that it could have been exploited, how do you get it back from Libya to mainland Europe with Malta still in British hands.
c. For it to be used to aid the war in North Africa that means building refining capacity there. That means transporting materials from mainland Europe.
This article highlights some of the difficulties facing the Italians in their occupation of Libya.
If it took experienced US oil companies years of geological exploration, then 2-3 years of drilling to find the first wells with commercial quantities of exploitable oil in the late 1950s and a further 2 before exports could begin. This is simply beyond the capabilities of the Italians pre-war, especially when you consider that their efforts to exploit reserves on the Italian mainland and Sicily came to virtually nothing.
And think about the political issues to be sorted out locally