Study Of The Oilfield Produced Water Treatment And Reinjection Technology In Low-permeability Reservoir

Considerable oily sewage is produced during oil & gas exploitation and development phase, such as produced water in multipurpose Station, backwater from flushing fluid, and discharge water out of well-drilling so on. In the meanwhile, substantial water is produced from oil wells at later stage of oilfield development, therefore, formation pressure depletes. In view of pressure-up keeping, plenty of water will be injected into wellbore. Water produced out of oil & gas wells is disposed and then is re-injected into production wells. On the one hand, the quality of sewage discharge will decline. There exists the balance between productions and injections.It is of vital industrial and environmental consequence. The source, dangerous effect sand sort of the oilfield produced water are summarized in this paper. Various traditional approaches to treat oilfield produce water are discussed in detail. On the base of this, the treatment process of ―Microorganism Plus Membrane‖ has been brought forward. Design and development of " mobile oil field sewage treatment equipment ".The integrated water treatment equipment based on the reinjection of oilfield sewage treatment engineering, The hydrolysis acidification, aerobic oxidation, MBR reactor and integrated in the standard 40 foot high cabinets container, The effluent indexes reach the standard of A1 SY/T5329-94, to meet the requirements of low permeability oilfield water injection. Sampling the soil from the surrounding yaotan oilfield long-term polluted, with crude oil as the sole carbon source was isolated by enrichment culture, screening of petroleum-degrading bacteria efficient. They are all gram-negative bacteria by Gram staining experiment. By changing the temperature、pH and carbon source, study on the physiological and biochemical characteristics of strains screened; according to the known(homologous) gene、degrading enzyme search, and design the gene amplification(mergers) primers, amplified by PCR, identify pathogens by 16 srDNA sequence analysis. Study on the influencing factors and degradation ability of oil degradation bacteria were screened, the strain was identified in the case of pH=7, the temperature is 35 ℃, substrate concentration is 1000mg/L, the salinity is 0.5g sodium chloride, the inoculation was 10%,5 days of its degradation rate can reach 62.87%, the best degradation performance; By random combination, design A, B, C, D, E, F, G seven groups of mixed bacteria. decomposing ability tests showed that the highest degradation rate is B. Through the optimization of environmental conditions on the culture of mixed bacteria, we got a group of bacteria that can be applied to industrial oily wastewater treatment.