Sensitivity of the spectral induced polarization method to microbial enhanced oil recovery processes

The demand for more efficient and economic oil recovery techniques has driven research into novel extraction approaches, including microbial enhanced methods. Microbial enhanced oil recovery (MEOR) is an underutilized technology that could significantly enhance tertiary oil recovery. Previous research has shown the spectral induced polarization (SIP) method to be sensitive to microbial degradation of hydrocarbons, so the method should therefore be sensitive to MEOR treatments. To test this hypothesis, heavy-oil-containing sands were monitored for a period of approximately six months while undergoing MEOR treatment. SIP monitoring showed significant sensitivity to biodegradation induced changes. Increases in phase and imaginary conductivity, with a polarization peak centered on approximately 3-8 Hz, were observed for the two MEOR active columns. Similarly, the normalized chargeability, an integrated parameter of a Debye decomposition analysis of the spectra, showed a linear increase in time. Chromatographic methods confirmed oil biodegradation in the active columns. The SIP responses are likely the result of microbial processes and the changes they promote to oil properties, such as altering wettability, or possibly the effect of organic acid production. The results of this experiment indicate that SIP may be a viable method of monitoringMEOR processes.