Oil formed in specific periods in ancient history. It does not form appreciably today. In the distant past you had these inland seas that became anoxic. That caused lots of material to deposit at the bottoms of these inland seas. The rotting anoxic crap was captures by sedimentary accumulation. If that additional layered deposit was impermeable, the organic material got cooked in and slowly changed to become denser oily material.
Anoxic states like we saw in specific (rare) periods in the past is not occurring appreciably right now. There are a few seas that are becoming “somewhat” dead right now, but not even a fraction of the degree needed to generate significant dead material layering. Most of the planet is dead desert at the moment, since we live in a post-glacial era. A lot of planetary carbon is sequestered as coal. We are a planet with very little biomass, compared to some earlier periods in geologic history.
SADLY – As they come, anoxic events are gruesome and deadly. Planetary anoxia is the worst and kills an appreciable percentage of complex organic life by means of literal suffocation. SO2 is extremely poisonous. So a planetary environment completely covered with tropical rainforests, 3 degrees warmer than we have now may not be completely desirable. The weather in such geological periods was absurd. Acid rain everywhere, constant rain and storms everywhere, dense forest at the poles, sea levels tens of meters higher than we have now, and (interestingly!) erosion rates (!!) hundreds of times as severe as we have now.
Imagine an erosion rate hundreds of times as severe as we have now. The planet could scarcely carry half a billion humans under those conditions.
So answering your question, none. No oil is “forming”, much in the same way “Saudi Arabia has no appreciable industries other than opil exports”. There is no significant formation of petrochemicals going on on the planet. At all. Once the stuff is gone the replacement is effectively zero.
If I were you I’d become disillusioned real quick and stop with the hope that the petrochemical era has anything of a future because it does not. The burning carbon era is ending in probably 1-2 decades, and almost certainly will end with a bang. There are sadly very few alternatives. We might coast along on a mixture of renewables and nuclear, but we are decades removed from fusion, matured solar, thorium or something as nice as SBPS. That means western developed society is set for mass unemployment, severe unrest, hunger, poverty, crisis and disparity, UNLESS we quickly democratize and ration remaining resources – and do within a few years.
“Coasting along” is not – mass consumerism, globalism, abundance like we have now. It is standards of living roughly comparable to standards of living of the median poor, in countries like Iran or Egypt or Pakistan. World wide. UNTIL we have thorium and SBPS online, but that won’t be for several decades.
My suggestion – literally kill oil executives and nationalize all oil companies. I’d personally argue for a state of emergency. There is a handy acronym for that – RBE ; Resource Based Economy.
I’d go further and call it “Constraints Affirming Economy”.