Abstract: In this paper, the methane-, butane- and alkane-oxidizing bacteria contents in oil and gas field soil was determined by the established real-time quantitative PCR（qPCR）technologies targeting the pmoA, bmoX and alkB gene respectively, and the background field soils were compared as the control. The pmoA and alkB gene copies decreased by 1-2 orders of magnitude with the sampling depth increased. The gene quantification results of DNA samples extracted by manual method indicated the pmoA and alkB gene copies in oil and gas field soils were slightly higher than in background field soils. The bmoX gene copies in gas field soils was 2.75×10⁵copies/g, which was 0.5-1 order of magnitude higher than that in background and oil field soils. The results of DNA samples extracted by kit method showed the pmoA and alkB gene copies in oil field soils were 3.09×10⁴ and 2.56×10⁶ copies/g, respectively, which were higher than that of gas and background field. The bmoX gene copies in gas field soils is 1 order of magnitude higher than that of background field soils, and 0.5 order of magnitude higher than that of oil field soils. It is concluded that the established qPCR method of the three oil and gas indicating bacteria provided new detection means for microbial prospecting of oil and gas.

Key words: Microbial prospecting of oil and gas（MPOG）, Real-time quantitative PCR, Methane-oxidizing bacteria, Hydrocarbonoxidizing bacteria