A Pilot Test Using Microbial Paraffin-Removal Technology in Daqing Oilfield

摘要

Microorganisms were screened from oil wastewater in Daqing Oilfield, by acclimatization, isolation and purification of microorganisms, bacterium as the only nitrogen source was obtained, which was named for strain Y-1. Experiment of identification showed that Y-1 was identified to Bacillus Cereus. Strain Y-1 was used for paraffin removal on three wells: Well Nos. 12-36, 13-39 and 14-43 in Yushulin Zone Daqing Oilfield. The results indicated that the tested wells obtained good effects after microbial treatment: the reduction rate of oil viscosity was 23.6%, the freezing point of crude oil reduced by 2.1°C, the reduction rate of oil surface tension was 38.0%, pH value was reduced from 7.2 to 6.2, daily oil production increased from 1.7t?d~(-1) to 2.4t?d~(-1), the rate of growth was 41.2%, the period of hot washings prolonged from 40d to 149d and the number of hot washings reduced by 4 times in Well 12-36; the reduction rate of oil viscosity was 24.8%, the freezing point of crude oil reduced by 2.7°C, the reduction rate of oil surface tension was 42.5%, pH value was reduced from 7.2 to 6.8, daily oil production increased from 1.2t?d~(-1) to 1.6t?d~(-1), the rate of growth was 33.3%, the period of hot washings prolonged from 45d to 158d and the number of hot washings reduced by 5 times in Well 13-39; the reduction rate of oil viscosity was 22.5%, the freezing point of crude oil reduced by 3.2°C, the reduction rate of oil surface tension was 42.5%, pH value was reduced from 7.2 to 6.4, daily oil production increased from 0.8t?d~(-1) to 1.1t?d~(-1), the rate of growth was 37.5%, the period of hot washings prolonged from 30d to 122d and the number of hot washings reduced by 5 times in Well 14-43. The direct economic income exceeded 210,000 Yuan.