Treatment Technology And Experimental Study On The Operating Wastewater Of Oil Field

In the process of oil field productions,it can produce a lot of fracturing flow-back fluid,drilling and repairing well waste liquid,acid waste liquid,etc.As the source of pollutions of oil field,these waste liquids are called the operating wastewater.The waste liquid entering into the natural environment will lead to serious soil and groundwater pollution.So with the development of the national and local request to the environment,the research on the treatment of the waste liquids of the oil field is more and more important.This paper selects the operating wastewater of an oil field as the object of the study.The purpose is to make the treated water fits the reinjection standard —Recommended index and analysis method of injected water quality of the clastic reservoir.Through the comparison of various treatment techniques,it can confirm that the treatment process of this paper is Electro catalysis—Multicomponent separation—Micro electrolysis—Multilevel filter.Reference index is the removal rate of oil content,SS and COD.The optimum operation conditions are determined through small-scale tests.Verify the effect of process treatment through the pilot-scale tests.By analyzing the water quality before treatment,it can confirm that the oil content is 44.452mg/L,SS is 155.4 mg/L,COD is 4515mg/L.The oil content is 9 times bigger than the reinjection standard.SS is 30 times bigger than the reinjection standard.The optimum operation conditions are determined through small-scale tests.(1)The optimum operation conditions of the electro catalytic test are that the electrode material is ruthenium iridium electrode,the current intensity is 5A,the electrolysis time is 60 mins and pH is 7.(2)The optimum operation conditions of the coagulation experiment are that the optimal dosage of No.1 reagent is 0.4mL/100 m L,the optimal dosage of No.2 reagent is 1.0m L/100 mL,the optimal dosage of No.3 reagent is 0.05 mL/100 m L and pH is 7.(3)The optimum operation conditions of the micro-electrolysis test are that the residence time is 30 mins and pH is 7.(4)Filtration test is the multi-stage filtration test.Through the small-scale tests,it can confirm that the removal rate of oil content is 81.72%,the removal rate of SS is 97.8% and the removal rate of COD is 93.75%.After the operating wastewater being treated through the pilot-scale tests,the oil content and SS of the treated water fit the reinjection water standards.The removal rate of COD is about 93% to 95%.The results of the pilot-scale tests are better than the results of small-scale tests.