The Research And Application Of Wastewater Reinjection Treatment Technology In United Station Of Chi-46Oil Field

It is unavoidable that whether the wastewater with oil can be disposed effectively or not. The reinjection of treated water can not only protect freshwater resources, but also maintain formation energy. It would be greatly helpful for sustainable development of oilfield.The producted sewage of Chi-46joint station of petroChina Changqing oilfield company which has large contents of oil, suspended substance, bacteria and sulfide.It was shown that the suspended solids and oil concentrations of the treated water are0.9milligram per litre and2.2milligram per litre respectively and the quantity bacterial are10individual per milliliter under the conditions of pH7.5, the dosage of NaCIO desulphurizing reagent of15milligram per litre, The PAC inorganic flocculating agent of80milligram per litre, The PAM organic flocculating agent of1.0milligram per litre and the interval of agent additive between30s and40s. In accordance with grey relational grade, the main factors which have influence on the corrosivity of oilfield produced water are dissolved oxygen, sulfide, oil content, TGB, sulfate-reducing bacteria, etc. After the integration treated with flocculation, anticorrosive and antiscale, the average corrosion rate of produced water reduced from0.1144to0.0253millimeter per year, Finally, the results indicated that the quality of the treated water meets the recommended quality standards of re-injection water.The fracturing fluid recovery of Chi-46which has complex ingredient and large contents of total iron, sulfide and chemical additive, high viscosity and emulsification is difficult treatment. It was shown that the suspended solids and oil concentrations of the treated water are22.5milligram per litre and4.5milligram per litre respectively, sulfide and total iron ions are all removal under the conditions of pH3.0, the dosage of NaCIO oxidant of1.25%, PAC inorganic flocculating agent of800milligram per litre, CPAM (12million) organic flocculating agent of5.0milligram per litre and the interval of agent additive between30s and40s. Finally, the results indicated that the quality of the treated water meets the recommended quality standards of joint station coming water.When the quantity of injected water and oilfield produced water do not match, we can use oxidation ponds process further treatment. The BOD5/COD of treated water is greater than0.3which can be treated with biochemistry. Then, the results indicated that the content of COD of the treated water meets the recommended quality standards of discharge water. Meanwhile, the content of aromatic structure compounds reduced, especially tryptophane aromatic structure protein and solubility microorganism metabolites are disposed obviously most.