Spatial Quantitative Distribution of Hydrocarbon-Oxidizing Bacteria of Unexploited Oil and Gas Fields
未开发油气田地表烃氧化菌空间定量分布

Spatial quantitative distribution of methanotrophs and C5-C16 hydrocarbon-oxidizing bacteria of different depths (30, 60, 100, 150, 200 cm) from the unexploited oilfield, gas field and control area was studied using Real-time PCR. The objectives of this study were to understand the quantitative distribution of hydrocarbon-oxidizing bacteria in the regions of unexploited oil and gas fields, and provide basic information for the development of oil and gas exploration techniques. The results showed that the gas field area had higher content of methanotrophs (pmoA), 1.34E+04-3.90E+05 copies·g-1, and the copies of pmoA decreased with depths. Compared with that in the gas field, it was lower with only 3.14E+02-4.32E+03 copies·g-1 in the oilfield. Remarkably, the oilfield had a relatively higher content of C5-C16 hydrocarbon-oxidizing bacteria (alkB) with 1.38E+07-3.61E+07 copies·g-1 soil below the depth of 100 cm than that in the gas field(5.82E+06-3.52E+07 copies·g-1) and the control area(4.24E+06-2.14E+07 copies·g-1). The distribution of methanotrophs was significantly affected by the total nitrogen, organic carbon, pH with correlation coefficients were 0.859,0.631 and -0.549 respectively. Within the depth of 100-200 cm, where physichemical properties such as total nitrogen, organic carbon, pH were relatively stable, the content of methanotrophs and C5-C16 hydrocarbon-oxidizing bacteria at different depths varied little. Furthermore, there was indeed abnormal methanotrophs in the gas field and abnormal C5-C16 hydrocarbon-oxidizing bacteria in the oilfield below the depth of 100 cm. Besides 100-200 cm was more suitable as the oil-gas exploration sampling depth in this study which also required further validation.