The primary difference between biogenic and abiogenic theories of petroleum origin lies in the source and process of formation. According to the biogenic theory, which is widely accepted in the scientific community, petroleum is formed from the remains of ancient plants and animals. These organic materials, after being subjected to heat and pressure over millions of years, transform into hydrocarbons, which are the primary components of petroleum and natural gas. This theory is supported by the presence of biomarkers—molecular fossils that indicate a biological origin.

On the other hand, the abiogenic theory suggests that petroleum originates from non-biological sources, such as the Earth's mantle. Proponents of this theory believe that petroleum is formed from deep carbon deposits through chemical processes that do not involve living organisms. This perspective implies that petroleum reserves are not limited by the availability of organic matter and could be virtually inexhaustible.

The abiogenic theory is less widely accepted, with the majority of the scientific community favoring the biogenic theory due to substantial evidence supporting the biological origin of petroleum. However, the debate continues, and both theories have implications for the sustainability and renewability of petroleum resources. For more detailed information, you can refer to sources like ResearchGate and Wikipedia.