Surface microbial geochemistry of the Beihanzhuang Oilfield, northern Jiangsu, China

Surface microbial geochemistry (SMG) is an effective tool to predict the occurrence of oil/gas deposits at the exploration phase. However, for oil/gas fields in the production period, the significance of SMG is always weakened since the existing microbial indicators for reservoir characterization by SMG are limited. In this study, we systematically analyzed the abundances of live and dead methane-oxidizing bacteria (MOBs) and butane-oxidizing bacteria (BOBs) in surface soils/sediments samples from two cores and 85 sampling sites in the Beihanzhuang Oilfield, China, using the culture-independent method. The results have demonstrated that the suitable sampling depth is 50 cm for this area; and the anomalies in the abundances of live and total MOBs/BOBs and their overlapping relation can clearly reflect the change in the horizontal distribution pattern of the subterranean oil reservoirs. A general SMG strategy integrated with novel microbial indicators has further been proposed in practical applications. Our work may provide a new clue for developing other new microbial indicators for SMG and promoting its wider applications.