Dynamic investigation of microbial activity in microbial enhanced oil recovery (MEOR)

The activity of reservoir microorganism is essential to Microbial enhanced oil recovery (MEOR). This present paper investigates the relationship between the microbial activity and production performance by means of long-scale & long-term experiments. The six rounds of nutritional injection was carried out in 135days. During the microbial flooding experiment was performed recovering additional oil (10.44% Original Oil in Place, OOIP) after first water flooding. There is a positive correlation between water content and shannon index. And the fourth round of nutritional injection causes a considerable reduction in water content, while the concentration of Methyl-coenzyme reductase subunit alpha (mcrA) reaches peak value. In microbial flooding and reference water flooding, the concentration of mcrA maintained higher level with the low concentration of acetic acid. There are intimate correlation between water content and mcrA concentration & bacterial diversity (shannon index), which can be consider the symbol to guide the MEOR filed test.