The Germans knew that oil would be crucial to the war and that they would likely need to capture new sources for the war effort.
The main oil-producing regions at the time that might be captured were the Caucasus region of southern Russia and the Middle East.
The Germans committed hundreds of divisions in their attempts to take the Russian oil but mere fractions of this to the African front, which was less well defended.
Why is this, and why were the following not considered to help:
Hitler had helped Franco in the Spanish Civil War, why not get the Spanish to capture Gibraltar thus tipping the balance of power in the Mediterranean decisively towards the Axis?
Were any political attempts made to get Turkey to join the war on the Axis side, thus allowing a second front to be opened in the Middle East and Russia?
Could the DAK have been activated sooner and with greater resources including more Luftwaffe support?
By staging a more aggressive campaign sooner, could the Germans have won in North Africa thus gaining sufficient oil in order to not have to worry about it when Barbarossa was launched?