Reference

The evidence for the deep origin of petroleum is a subject of scientific debate. While the mainstream scientific consensus supports a biogenic origin for petroleum, which means it is formed from the remains of ancient organisms, there are alternative theories suggesting an abiogenic origin. According to these theories, hydrocarbons are generated from deep within the Earth's mantle and can migrate into the crust. Some of the evidence cited for a deep origin includes the presence of natural gas and petroleum fluids in the Earth's crust, the existence of hydrocarbons in metamorphic rocks, and isotopic evidence that suggests a non-biological source for some hydrocarbons.

However, it's important to note that the majority of the scientific community does not support the abiogenic theory due to a lack of substantial evidence and the overwhelming support for the biogenic theory. The biogenic theory is supported by a wide range of geological, chemical, and biological evidence, including the presence of biomarkers in oil and the correlation of oil reserves with ancient organic-rich sediments.

In conclusion, while there are some theories and limited evidence suggesting a deep origin for petroleum, the scientific consensus overwhelmingly supports a biogenic origin. For more detailed information, you can refer to sources such as the article on the "Abiogenic petroleum origin" from Wikipedia, or the research paper titled "Deep‐seated abiogenic origin of petroleum: From geological indicators to quantum calculations" published in the journal Reviews of Geophysics.