The earth produces over 100 million tons per year in organic carbon.
http://www.sciencemag.org/content/281/5374/237
If only 0.01% of that become trapped in sediment on lake and ocean beds, it equals 4 trillion tons after 400 million years.
From the article, the organic carbon produced is over the entire earth, whereas coal and oil are by popular definition, concentrated areas of organic materials.
They are hydrocarbons, and carbon is found over the entire earth.
It is nothing for God to use these chemical building blocks to create oil and coal for us to use.
Again,the density of strictly animal and plant matter required to produce a trillion barrel reserve of oil, such as off the coast of Israel, would be unimaginable in quantity.
But that does not fit the story of the dinosaurs falling in pits and plants falling over them and being squashed into oil and coal over hundreds of millions of years.
Prove the earth has been around 400 million years.