Study On Oxidation Treatment Of Waste Fracturing Fluid In Oilfields

Fracturing technique is not only an effective measure to increase oil productions and injections, but also the important method to reconstruction oil/gas layer. With the rapid development of petroleum industry, Fracturing process has been broadly used in oil/gas exploration and development in domestic and foreign oilfields. Therefore, the fracturing fluid produced in the process of fracturing operations, becomes one of the source of polluted water. In order to carry out the cleaning production actively, the harmless treatment of underground operation wastewater, including fracturing fluid and acidizing fracturing fluid remaining, becomes a serious problem.According to the analysis of the source, chemical compositions, classification, present treatment condition and technical trends of fracturing fluid, and based on the water quality of fracturing fluid in oilfields, this paper design a series of related technologic process flows to reduce the contaminant load in the fracturing fluid. On the basis of monitoring data, we put forward to the"Two-Step"to treat the waste fracturing fluid in oilfields. The technologic process flow of 1^#fracturing fluid is followed:"coagulation and settling-ClO₂ catalytic oxidation", The technologic process flow of 2^#fracturing fluid is followed:"NaClO oxidation-Fe/C micro-electrolysis".In this paper,each of mechanisms of the treating method has been discussed, The optimum technological conditions were confirmed by a great deal of experiments, After pretreatment,1^#effluent water is clear and transparent, the COD of the fracturing fluid decreased to 149.57mg/L from 3759mg/L, the removal rate reaches 96%. 2^#effluent water is clear without deposit, the COD of fracturing fluid decreased to 124.74mg/L from 2695mg/L, the removal rate reaches 95.37%. Finally, the post-treatment water were characterized by UV-VIS absorption spectrat, the experimental results and theoretical analysis indicate that the quality of fracturing fluid, disposed by"Two-Step", met the discharge standard.