Concerning the formation of oil, geologist Dr. Andrew Snelling states:
Crude oils themselves do not take long to be generated from appropriate organic matter. Most petroleum geologists believe crude oils form mostly from plant material, such as diatoms (single-celled marine and freshwater photosynthetic organisms) and beds of coal (huge fossilized masses of plant debris). The latter is believed to be the source of most Australian crude oils and natural gas because coal beds are in the same sequences of sedimentary rock layers as the petroleum reservoir rocks.
Thus, for example, it has been demonstrated in the laboratory that moderate heating of the brown coals of the Gippsland Basin of Victoria, Australia, to simulate their rapid deeper burial, will generate crude oil and natural gas similar to that found in reservoir rocks offshore in only 2–5 days.
All the available evidence points to a recent catastrophic origin for the world’s vast oil deposits, from plant and other organic debris, consistent with the biblical account of earth history.
Vast forests grew on land and water surfaces in the pre-Flood world, and the oceans teemed with diatoms and other tiny photosynthetic organisms. Then during the global Flood cataclysm, the forests were uprooted and swept away. Huge masses of plant debris were rapidly buried in what thus became coal beds, and organic matter generally was dispersed throughout the many catastrophically deposited sedimentary rock layers.
The coal beds and fossiliferous sediment layers became deeply buried as the Flood progressed. As a result, the temperatures in them increased sufficiently to rapidly generate crude oils and natural gas from the organic matter in them. These subsequently migrated until they were trapped in reservoir rocks and structures, thus accumulating to form today’s oil and gas deposits. (“The Origin of Oil,” Answers 2:1, 2007, pp. 74–77, online at www.answersingenesis.org/geology/the-origin-of-oil/.)