System and method for electrochemically treating high-viscosity fracturing flow-back fluid

Abstract

The invention discloses a system for electrochemically treating a high-viscosity fracturing flow-back fluid. The system comprises a pH adjusting unit, an electrocatalytic oxidation unit and an electric flocculation unit which are arranged in sequence, wherein the pH adjusting unit is used for adjusting the pH value of the fracturing flow-back fluid to 4-7, the electrocatalytic oxidation unit comprises an electrocatalytic oxidation device, and the electric flocculation unit comprises an electric flocculation device connected with effluent of the electrocatalytic oxidation device. The inventionalso discloses a method for treating the fracturing flow-back fluid. The method comprises the following steps: 1) adjusting the pH value of the fracturing flow-back fluid to be treated to 4-7; 2) performing electrocatalytic oxidation treatment on the fracturing flow-back fluid obtained in step 1); and 3) performing electric flocculation treatment on effluent in step 2). The treatment system and the method mainly adopt electric energy to achieve the treatment of the fracturing flow-back fluid, so the system and the method accord with the clean production category; and a large amount of an organic or inorganic polymer agent is not needed in the treatment process, so the system and the method have the advantages of no secondary pollution, stable effluent quality, and saving of resources and cost.

Description

technical field [0001] The invention relates to an electrochemical treatment system for high-viscosity fracturing flowback fluid and a corresponding treatment method, belonging to the technical field of sewage treatment in the petrochemical industry. Background technique [0002] Fracturing flowback fluid refers to the residual fracturing fluid remaining after fracturing operations and flowing back from the wellhead. Due to the addition of many additives during fracturing, the residual guar gum, suspended solids, crude oil, part of the brine in the formation brought out during flowback, and other organic additives in the fracturing waste fluid are toxic and harmful and difficult to degrade. Substances, resulting in complex and changeable components, high chloride content, often present the characteristics of "three highs" (high viscosity, high stability, high COD value). If the fracturing flowback fluid is directly sent to the existing sewage treatment system for treatment,...

AI Technical Summary

Problems solved by technology

Or use electrochemistry and chemical oxidation flocculation in combination, but the process is long, chemical consumption and sludge production are also large

For example, CN106315934A discloses a fracturing flowback fluid treatment experimental device, which integrates various process units such as chemical oxidation, ozone oxidation, chemical flocculation, and electrocoagulation, and has defects such as long process and large floor space; and CN107235580A discloses The oilfield drilling and fracturing flowback fluid treatment method adopts a combination of pretreatment, electroflocculation and electrocatalytic oxidation, but the efficiency of the process route is low, and the process unit repeats lengthy

[0005] In addition, according to statistics, most domestic oilfield fracturing flowback liquid water is generally stored in the vicinity of the well site, which has the characteristics of dispersion and discontinuity, and it is difficult to deal with it in a unified manner

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