The Research And Application Of Wastewater Treatment Technology In Jingerlian Oilfield

In the oil field development, especial the process of developing low permeability reservoirs, fracturing is one of universal application of the stimulation. With the characteristics of high viscosity and stability, high organic content, difficult dealing with, backflows after fracturing has become one of the main oilfield pollution sources during the fracturing. In this issue, by analyzing the fracturing fluid source, water quality characteristics, status and prospects of treatment, according to the characters of different viscosity of fracturing wastewater of Ansai oilfield, chose the Fenton oxidation, coagulation and settling treatment to joint analysis, discuss the effect of the de-emulsification, scaling and corrosion on crude oil gathering system when treated wastewater transport through.. So that the treated wastewater has the characteristics of low corrosion, different to scale and little impact on de-emulsification by the crude oil of the transportation system, which had reached the basic requirements of the reinjection water.For more than 10mPa·s viscosity of the fracturing waster water, firstly, put it into acidizing by sulfuric acid, then chose the Fenton oxidation-flocculation treatment, mixed the treated wastewater and produce wastewater with the ratio of 1:9 and treated the mixed water with routine processing, which had a obvious effect with optical transmittance of the treated wastewater rose from 0.7% to 73.9% and visually clear.For the viscosity less than 5mPa-s of the fracturing wastewater, treatment of the oilfield fracturing wastewater by Fenton oxidation-flocculation.The dosage of H2O2 and FeSO4 were 0.2%～0.6% and 15～20 mg/L respectively, adjusted the pH to 3.0～10.0, the dosage of PAC and PAM were 30～50 mg/L and 1～5 mg/L, with 30s interval, and the pH value of the treated wastewater is adjusted to 7.5.The results show that the standards of the treated water had achieved quality standards of the reinjection water of Ansai oilfield.The contents of suspended matter and oil in treated wastewater were 2.0～2.5 mg/L and 4.37～5.22mg/L, the average corrosion velocity and content of bacteria were 0.0127～0.0155mm/a and 0 respectively.The treated wastewater has the characteristics of low scaling tendency,the loss rate of calcium in mixed water was less than 10%. The treated wastewater can transport by crude oil gathering system and do not effect the de-emulsification of the crude oil.