Playing as Sovs, and lack of oil has never been a problem for me before so I have never worked out how the synthetic oil plants work. In my current game in early '43 I have the synthetic oil plant slider at to the extreme right (and have 'improved refining' tech if that makes a difference, and +92 energy per day), but no oil is produced. The slider under it, synthetic materials, does work if I move it to the right. I'm probably missing something obvious, please advise.