A New Method Of Processing Oil Field Fracturing Fluid Flowback

Fracturing operations is an important measure to increase production of oil-gas fields, andalso improve the flow capacity of the hydrocarbon reservoir. It can generally be used by bigoilfield. While after the operation, it will produce large of waste liquid which returns to theground. The liquid will become one of the main sources of pollution of water bodies.Currently at home and abroad, the solidification method, micro-electrolysis method,biochemical method, supercritical water oxidation method are often used for processingmethod of fracturing fluid and flowback, but each method used for wastewater treatment is notcompletely. Compared with several other processing methods, micro-electrolysis method is aneconomical and efficient processing method, but the micro-electrolysis method has its owndeficiencies, such as iron surface passivation and iron carbon easy to harden, which reducesthe processing efficiency during the reaction process. To solve this problem, this paperproposes a set of treatment process, namely: oxidation of gel breaking-cavitation impingingstream reactor combined with micro-electrolysis method-Fenton oxidation process.In this paper, Jilin Oilfield1#fracturing fluid and flowback are treated as researchsubjects, and the following aspects are studied:(1) Combined processing mechanism of fracturing fluid and flowback research and theanalysis of water pollutants. Known from the analysis of water pollutants, fracturing fluidand flowback CODCrvalues can be up to8910mg/L, suspended solids as high as236mg/L,high oil content, and viscosity is three times that of water.(2) Oxidants screening. Researcch showed that, under the same condition, ammoniumpersulfate gel breaking effect is best, and after processing, the wastewater is clear and CODCrremoval rate can reach34%.(3) Study of micro electrolysis reaction conditions. The optimum reaction conditions ofmicroelectrolysis is as follows: initial pH value of2.0, the iron carbon mass ratio is4:1,reaction time is120min. Under the condition, the CODCrremoval rate can reach36.5%.(4) Research on iron carbon micro electrolysis is affected cavitation impinging streamreactor. Under the same reaction conditions as above, we adopted cavitation impinging streamreactor for micro electrolysis reaction, the reaction time is90minutes, and the CODCrremoval rate reached41.8%.(5) Research on optimal reaction conditions of Fenton oxidation. The optimal reactionconditions were determined: the concentration of30%H2O2is2ml/300ml, the pH value of3.0, reaction time is60min, the CODCrreduced rate is of16.2%.Research showed that the combined process of fracturing fluid flowback fluid has goodprocessing effects, and the total CODCrremoval rate of processed wastewater reached92%.Cavitation impinging stream reactor and micro electrolytic method are in good coordinationwith each other. Compared with traditional micro electrolysis, this method not only makes thereaction time shortened by25%, but also increases the CODCrreduction rate by5.3%. Inaddition, after iron carbon micro electrolysis, Fe2+is contained in wastewater, which plays acatalytic role in the subsequent Fenton oxidation, so we do not need to provide the iron saltand can achieve cost savings. The combined technology provides an economical and efficientnew method to deal with fracturing fluid flowback fluid. It could have broad applicationprospects and will bring much economic benefits to our society in the near future.