Fig. 6

Key parameters and the schematic diagram of oil displacement experiments using Enterobacter sp. FY-07 and FY-0701. a Pressure, water cut, and oil recovery efficiency of column A; b Pressure, water cut, and oil recovery efficiency of column B; c The schematic diagram of Enterobacter sp. FY-07 in oil displacement process. d The schematic diagram of Enterobacter sp. FY-0701 in oil displacement process. Column A and B correspond to column A and B in Table 4. Pressure was recorder during the experiment process; Water cut was calculated by the Eq. (3); The oil recovery efficiency was calculated by the Eqs. (2) and (4). Gray polygons indicate porous medium, blue area indicates water flow, black area indicates crude oil, yellow circles indicate bacteria, red stars indicate BC, and black circles indicate crude oil that was displaced