A Comparative Study of the Geochemical Characters of Crude Oil after Microbe Degradation in Laboratory

Based on the analyses of the four crude oil samples in Shengli oil fields, it is found that microbe can degradate the crude oil in laboratory. After the microbe degradation, the crude oil samples have low saturated hydrocarbon contents and low saturated hydrocarbon/aromatic hydrocarbon ratios, and high aromatic hydrocarbon, non-hydrocarbon and asphaltene. It also shows that the normal paraffin hydrocarbon of crude oil has a deep degradation after microbe degradation , and a low Pr/Ph value and a low ∑C_ 21-/∑C_ 22+ ratio. After the action of microorganisms on crude oil, some surface-active substances produced,and caused low surface tension.