Influence of ferrous iron on the oxidation of crude oil at a low temperature

ABSTRACT

Air flooding can be successfully applied in a low-temperature reservoir due to the existence of ferrous ions in formation water. However, few published papers can be found about the mechanism of oxidation of crude oil on condition with Fe²⁺ at a low temperature, by far. Therefore, in order to reveal the mechanism, some static oxidation experiments are carried out at 30°C in this paper. On condition with Fe²⁺, the rate of oxygen consumption is increased by 2.3 times as that on condition without Fe²⁺, and the concentration of O₂ in the air is decreased to 7.5% after oxidation. According to the results of the changes in the compositions of the air and the crude oil, not only can Fe²⁺ accelerate the rate of the oxidation but can also affect the pathway of the oxidation. The experimental results can provide a basis for how to further improve the development effect of air flooding in Ganguyi oilfield and safely make use of air flooding in other low-temperature reservoirs.

KEYWORDS:

• Acceleration
• air flooding
• ferrous ion
• low temperature
• oxidation reaction

Funding

This study was supported by the Fundamental Research Funds for the Central Universities (16CX02020A) and the national natural science funds (51274229; 51104173).