where, there is more plant and animal life than ever before in earth's history, which means that, there will be a correspondingly equal amount of dead material being deposited. Dinosaurs might have been huge, but, the totality of life on earth now, is much bigger than in prior epochs.
But, petroleum or oil, may not have depended on dead organic material to be created.
"Everybody seems to believe in Hubbert's Peak Oil Theory. Why do you believe in this theory? Within this article I present fairly convincing evidence that Peak Oil is a theory based on a false premise - that oil is a finite resource."
"The suggestion that petroleum might have arisen from some transformation of squashed fish or biological detritus is surely the silliest notion to have been entertained by substantial numbers of persons over an extended period of time." Sir Fred Hoyle FRS 1982.
"The general concept of petroleum formation by biogenic mechanisms has been firmly entrenched for a long time, but there has been no accumulation of convincing experimental evidence in support of this belief." -- Charles E. Melton and A.A. Giardini, 1983"
Peak Oil, just like the junk of global warming, are very flawed theories, and not provable in any real scientific manner.
http://www.escapistmagazine.com/forums/read/18.353778-Peak-Oil-is-a-false-hypothesis-as-oil-is-not-a-finite-resource 
