Not quite. The vast majority of petroleum comes from the remnants of microorganisms like algae. They settle in anoxic aqueous environments, are buried over mill

Not quite. The vast majority of petroleum comes from the remnants of microorganisms like algae. They settle in anoxic aqueous environments, are buried over millions of years, compressed and transformed into organic rich rock called kerogen. If that kerogen is buried to sufficient depth and temperature it then cooks and is converted to oil and gas. Trees and plant matter typically turn into peat and eventually coal.