Now some dinosaurs undoubtedly did become oil deposits too, but not enough to matter. There simply weren't enough of them.
Dig a little deeper and you will see the clay under it, and the limestone under that. and then the granite. I own plenty of peat bog land. No chance of it ever becoming oil wells no matter how many billion years you give it. It simply breaks down into soil after all the vegetation completely decays. What makes pete bogs is lowlaying grasslands, swamp grass and reeds that die off every year and pile up. eventually the soil builds up raising that low land and the process stops. No oilwell, sorry. just nice black dirt.
The dead se animals etc doesn't wash either. it simply doesn't add up. Plus, most of that turns to methane and decays completely long before it becomes buried.
Oil is found much deeper than that, were there are no dinosaur bones, no sign of any organic life whatsoever. It's very difficult to explain how all this stuff got under the earths crust- 5 miles think and more in places. Oh they try, but there is no evidence to back up that theory.
Oil must really go through some amazing process, because there are no organic markers found in oil, only what is present as a contaminant which gets into it as it is brought up through the sedimentry layers.