Progress in key technologies of scaling prevention and treatment in ASP flooding

In application of enhanced oil recovery in Daqing Oilfield, ASP flooding increases the oil recovery by about 20% and 6%−10% compared with water flooding and polymer flooding respectively. Nevertheless, existence of alkali causes serious scaling in the mechanically pumping wells, which increases the difficulty in oil production and the intensity of maintenance, and it is a factor restricting industrial application of ASP flooding. Pilot in ASP flooding and research on dynamics of scaling and the long-term interaction between the ASP system and the reservoir rock have been carried out in Daqing Oilfield. The mechanism of calcium-silicon composite scaling was revealed, and the method of qualitative and quantitative prediction of scaling was established. The anti-scaling artificial lifting equipment was developed through structural design and nano-spraying modification of low surface energy materials. A composite anti-scaling agent with the scale-cleaning and anti-scaling rate above 85% was developed based on the scaling mechanism. Through combination of physical and chemical prevention, the pump inspection period of oil wells is greatly extended, and the problem of short continuous production period due to scaling is resolved. This promotes large-scale application of ASP flooding.