A Study On The Polymer Solution Preparing With Oil Produced Water

With the continual enlarging of production scale of polymer flooding industrilization,the provision of low-salinity water increases,the disadvantagel depending on the low-salinity water to configure and dilute polymer solution stands out.In the process of displacement of oil by polymer solution, the viscosity and viscoelasticity of polymer solution are vital to displacement efficiency. The consumption of fresh water in oil field has increased dramatically as the extension of polymer- displacement industrialization. Meanwhile extremely large amount of produced water has to be drained away, directly resulting in water resource waste and serious environmental pollution. To resolve this problem, LaMaDian Oil Field embarks on the study of using produced water in polymer-displacement process to realize recycle application of produced water.Tests show: microbes and reducing substances in produced water are major factors to influencepolymer solution's viscosity. Although the TDS of produced water is relatively high, the polymer solution mixed with it can still maintain a higher viscosity. At the same time, this kind of polymer solution has a desirable property to match the reservoir, and demonstrate a better ability to maintain its viscosity in simulative reservoir; a lot of tests prove that the method of exposure-to-oxygen is a economical and logical way to treat microbes and reducing substances existing in produced water; combining studies of viscoelasticity and displacement ability of polymer solution preparing in fresh water and produced water respectively with the latest mix and injection process, an injection method is determined finally that preparing super- high molecule weight polymer solution in fresh water and diluting it with produced water after exposure-to-oxygen treatment.The result shows that aerobic produced water, increasing polymer concentration and using high molecular weight polymer can increase the viscosity of polymer solution with produced water. This achievement is used in a pilot test and has a good effect.