Characteristics of bacterial communities in shallow and thin heavy oil reservoir

Revealing the characteristics of microorganisms that inhabit oil reservoirs is important in the effective application of microbial enhanced oil recovery (MEOR) technique. Plenty of studies have been conducted to discover microbial communities in light oil reservoirs, but investigations on the characteristics of bacterial communities in shallow and thin heavy oil reservoirs are limited. The aim of this study is to investigate bacterial communities in shallow and thin heavy oil reservoir, an oilfield in Henan (China) was taken as an example, and the 16S rDNA clone library approach was adopted to analyze the composition, abundance, and distribution of bacterial communities. A total of 682 sequences obtained from the four clone libraries were assigned to 84 operational taxonomic units (OTU) and 11 bacterial groups were identified in the oil reservoir. Results demonstrate the following: (1) The heavy oil reservoir has low bacterial diversity. (2) Differences exist in the bacterial community structures of the clone libraries. (3) The distribution of bacterial communities is consistent with the temperature, salinity, and oil properties of the oil reservoir. The findings of this study can provide basic theoretical guidance for the application of MEOR in shallow and thin heavy oil reservoirs.