Characteristics of Bacterial Communities in High-Temperature Heavy Oil Reservoir

Revealing the characteristics of microbes inhabiting in oil reservoirs is significant for the effective application of microbial enhanced oil recovery (MEOR) technology. Many studies have been carried out to discover microbial communities in conventional oilfields, and medium- and low-temperature heavy oil reservoirs. However, few explorations on the characteristics of bacterial communities in high-temperature (>50 °C) heavy oil reservoirs are conducted. In this study, Bamianhe oilfield (China) was taken as an example and the 16S rDNA clone library technology was adopted to analyze the composition, abundance, and distribution of bacterial communities in a high-temperature (60 °C) heavy oil reservoir. A total of 715 sequences obtained from the four clone libraries were assigned to 130 operational taxonomic units (OTU) and 20 bacterial groups were identified in the oil reservoir. Results demonstrate that (1) the heavy oil reservoir has high bacterial diversity, and thermophilic bacterial communities are predominant. However, there are differences in bacterial community structure of clone libraries based on the correlation analysis. (2) The distribution of bacterial communities is consistent with the temperature, salinity, and oil properties of the oil reservoir. The findings of this study provide basic theoretical guidance for the application of MEOR in high-temperature heavy oil reservoirs.