The Research And Application Of Wastewater Treatment Technology In Qinger Lian

At present, most of our oilfield has entered the mid-late oil drilling, namely high water-cut stage. Qingerlian joint station of Changqing oilfield located in qingyang of Gansu province, the oilfield has entered into the injected stage, and the produced water is used for injection. But the produced water is a multiphase system consisted of suspended solid, oil and soluble materials after the oil-water separator, and should be reinjected after treatment due to its higher reservoir harmful, strong corrosive and certain scale property.The characteristic of producted sewage in Qingerlian joint station is that it has large contents of suspended solids, sulfide, oil and bacteria, serious corrosion scaling. In this study, treated sewage water could be reached to reinjection standard through, oxidation flocculation, anti-scaling and corrosion-controlling to the process of wastewater treatment. The pH adjustment-Chemical oxidation-Flocculation-water filtration technology is the main processing procedure. By single factor and orthogonal experiment method, the best processing conditions and dosing system is that the pH is7.4to7.5with4%NaOH solution adjusting, the concentration of desulfurazation agent H2O2is60-70mg/L after fully mixing, PAC is90-100mg/L and PAM is1.5-2.0mg/L, inorganic and organic polymer flocculant intervals is30s, the N corrosion inhibitor is40mg/L; the third microbicides is60-70mg/L; the third inhibitor is60mg/L. Eventually the results of commissioning indicate that the contents of oil, sulfide,bacteria,corrosion rate of quality indexes are8.7mg/L(<10.0mg/L),1.4mg/L(≤2mg/L),0ge/L(SRB≤10ge/L),11-35ge/ml,(TGB≤100ge/ml),0.031mm/a (≤0.076mm/a) respectively.The treated water is stable and good compatibility with the formation water.The core flow sensitivity of experimental results show that velocity sensitivity is weak speed sensitive; Water sensitivity and salt sensitivity is belonged to be medium. Therefore, the treated water reinjection has low damage to stratum and has good compatibility with formation-water.Simulation results of sewage water conditions of Qingerlian and the research on high sulfur content show that the sewage water sulfide reach to the reinjection standard, by using complex formulation desulfurazation reagent ZnCl2+H2O2(the mass ratio is7:3)which mass concentration is70mg/L.