Study On Drilling Waster Water Advanced Treatment Technique For Dagang Oilfield

Drilling waste water, the mixture of high power dilution and oil, is the main component of oilfield waste water and major sources of pollution. The composition is complex and could lead to more serious environmental pollution problems if discharged diretly without treatment. In view of characteristics of waste water of BH13×1 well and three typical waste drilling fluid systems in Dafgang oil field,"chemical coagulation - catalytic oxidation - activated carbon adsorption"triple combination treatment process was adopted.Firstly, to treat the drilling waste water of BH13×1 well, the influnece rule of inorganic coagulants and their concentration, organic flocculants concentration, pH and additive adding methods to coagulation effect were studyed and technique conditions were optimized. Aimed at typical drilling fluid systems used in Dagang oilfield, the effect of coagulants on destabilization-flocculation was researched and inorganic coagulant IPA-I and organic flocculant OF-1 were adopted to treat the waste water in this area. Based on this orthogonal experimental was designed and best combination process conditions of the three typical waste drilling fluid were determined. After chemical coagulation treatment, water quality of site waste water and three typical waste drilling fluid were significant changed. The removal efficiency of suspended solids, chroma and COD and other detection indexes was all above 90%.After coagulation of three typical waste drilling fluid, H2O2/Fe (Ⅱ) catalytic oxidation technology was used to further degrade the COD of coagulated water. The conditions of corresponding process were established through the affecting factors researching like oxidant, catalyst, assist catalyst, acidity and reaction time. After H2O2/Fe (Ⅱ) catalytic oxidation treatment,the COD of coagulated water was removed effectively which satisfied or got close to the national emission standards.Finally,to part of coagulation- catalytic oxidation water, active carbon adsorption method was used and the adsorption conditions were optimized in order to get close to relevant national emission standards.After"chemical coagulation - catalytic oxidation - activated carbon adsorption"triple combination treatment process, the removal rates of treatment index including pH, chroma, turbidity and COD of drilling waste water of BH13×1 well and Dagang oilfield three typical waste drilling fluid systems were all above 99%. The final results of water treatment quality were consistent with the secondary emission standard of Integrated Wastewater Discharge Standard (GB8978-1996).