Vanadium, Ni, S and Hg contents in Bulgarian crude oils: Genetic and environmental implications

We report new V, Ni, S, and Hg data for four condensates and seven crude oils from Central Northern and Eastern Bulgaria. The samples have relatively low trace metal contents compared with other published crude oils and condensates. These properties facilitate their production and reduce environmental concerns for trace metal release from the processed products. Low S contents at moderate Ni/V ratios for all oils from Central Northern Bulgaria suggest origin from clastic source rocks deposited in mildly reducing conditions. In contrast, the Tyulenovo oil from Eastern Bulgaria has high Ni/V ratios at low S contents, indicating possible origin from lacustrine source rocks.