There is a GIGO issue in this
It looks like some of the reserves, maybe a fair amount, were confabulated to support high share prices of some companies, and likelythe egos of some OPEC aparatchiks.
That said, I think the reserve situation is very good, and will collapse quickly. My grandfater used to tell the story of how the 'End of Oil' was predicted when he was young, in the late 19-tens and early 1920's. While the state of the science is much better now, we are nowhere near 100% knowledge of oil country around the globe.
Oil is just another mineral in most respects. And the earthis full of a lot more minerals than we will ever use.
Ed