Aerobic acclimatization cultures of oil production water from two adjacent oil production wells (Xi15-14 and Xi51-5) in one block of Dagang oilfield were generated depending on crude oil as the sole carbon source and energy. Both cultures revealed a high degrading efficiency for a wide range of hydrocarbons, but degradation trend were striking different, and surface tension of two phases of oil and water decreased from 60 to 30 mN/m approximately by virtue of indigenous microbial metabolic activities. Meanwhile, cultured indigenous bacteria of wellXi15-14 mainly included Hydrocarboniphaga, Pseudomonas, and Ectothiorhodospiraceae bacterium, while wellXi51-5 contained Sphingomonas and Pseudomonas. Furthermore, abundance of alkane hydroxylase genes alk B and alk M from the two samples also showed an apparent difference. These findings are important that microbial diversity tightly tallies with the fact of a highly compartmentalized stratigraphy of this oilfield, suggesting that it is better to recover oil from extreme reservoirs with the targeted stimulating indigenous microorganisms.