They thought they needed the oil from Caucasus!

Two points to ponder:
- it would be feasible to increase synthetic oil production (assuming it could be protected from bombig);

- *if* they could get to the oilfields it would be an enormous effort and time taken to extract useful quantities (even if the wells were not sabotaged) due to lack of German oil extraction know-how (no technical base);

- assuming they managed to extract useful quantities, it would be a problem bringing the oil home all the way from the Caucasus. No pipelines extant, few or no rail-links to the Caucasus, whatever rail network there would be would already be clogged with military traffic. This might be achieved, but due to the time and effort this would require, only after a hypothetical German victory.

That makes three points, not two

As a practical example of all this, see Hitler's obsession with the Donbass mines. He went to great lengths to maintain possession and after all the effort only marginal amounts of manganese came out of it, possibly only from the extracted mineral stockpile. Why would it be better with the oil?

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