Look at events\goods.txt file in game directory (or common\events\goods.txt, can't check right now). It contains detailed description of oil and rubber provinces and years when these events will be enabled (Look at OIL EVENTS and RUBBER EVENTS sections). Good thing is that in last AHD patch oil events were even commented (province name, not just ID). Oil events start to pop up after 1870, rubber - after 1880.
Keep in mind though, that in AHD oil and rubber can't be discovered if the country (or its master) has no techs (oil cracking, automobiles, etc), so basically there's no oil before 1880, since Russia and its asian neighbors are lame in techs. But you can "Free People" on Russian Azerbaijan to put them in your sphere, so you'll have oil in early 1870s and start building refineries.
But it's not the number of provinces that matters, but population and techs (except if you want to monopolize oil).