Reference

Trace metals are frequently found in natural petroleum oils due to several reasons. They originate from the Earth's crust and are incorporated into the oil during its formation from organic matter under the Earth's surface. The most common trace metals in crude oils are vanadium and nickel, which are typically present in oil-soluble forms. These metals can also be introduced into the oil during its migration through the reservoir rock, which may contain these metals. Furthermore, trace elements like nickel and vanadium are crucial for understanding oil formation, oil-oil correlations, and oil-source rock correlations, as indicated in a comprehensive review and new data presented on ResearchGate [1].

The presence of these trace metals can affect the refining process and the quality of the final petroleum products. For example, vanadium and nickel can cause catalyst deactivation during refining, leading to increased operational costs. Other trace metals such as calcium and magnesium are also found in oil, but generally have little effect on the oil's performance [5].

In addition to their geological significance, some trace elements are necessary for the growth of oil-degrading bacteria, playing a role in the bioremediation of oil spills [7]. The presence of heavy metals in plants from oil sand deposits may also reflect mineralization resulting from petroleum biodegradation [8].

Overall, the occurrence of trace metals in petroleum oils is a result of their natural presence in the Earth's crust, their incorporation during oil formation and migration, and their role in refining processes and environmental interactions.