Treatment method of polymer flooding and binary combination flooding-SP-sewage

Abstract

The invention provides a treatment method of polymer flooding and binary combination flooding-SP-sewage, which comprises the following steps: sequentially adding 30-50 mg / L industrial ferrous sulfate and 30-50 mg / L industrial ammonium persulfate in a concentration ratio of 1:1 into sewage in a sewage tank at a time interval of 15-20 seconds, and after reacting for 1-2 hours, sending into a sewage buffer tank; adding 150-1500 mg / L coagulant in the sewage from the sewage buffer tank before pumping, evenly mixing by a lifting pump impeller, sending into a cyclone reactor to react for 1.5-2.0 minutes, adding 8-12 mg / L anionic-type partially hydrolyzed polyacrylamide flocculant, carrying out cyclone reaction for 1.5-2.0 minutes, and sending into a sedimentation tank; sedimentating for 10-30 minutes to obtain purified water on the middle lower part, wherein the suspended substance concentration and oil content are less than 10 mg / L; and filtering to obtain injection water for low-permeability reservoirs, wherein the coagulant is prepared from 100-300 parts of aluminum sulfate, aluminum chloride or polyaluminium chloride, 1-300 parts of industrial hydrochloric acid, 20-100 parts of polydimethyldiallylammonium chloride and 300-780 parts of tap water.

Description

technical field [0001] The invention relates to the treatment of sewage in oil and gas surface engineering, and is especially suitable for the purification treatment of sewage in polymer flooding and binary compound flooding (SP). Background technique [0002] The biggest difference between polymer flooding and binary compound flooding (SP) sewage and oilfield water flooding sewage is that it contains polyacrylamide and surfactants as oil displacement agents. It is also because of the existence of oil displacement agents that polymer flooding and binary The properties of composite flooding (SP) sewage are very different from those of conventional water flooding sewage, which are manifested in: the suspended matter points in sewage are highly dispersed and stable, the emulsification is serious, and it has the characteristics of oil content, high suspended matter content, and small particle size; anionic polymer Seriously interfere with the coagulation process of water purifie...

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Problems solved by technology

[0002] The biggest difference between polymer flooding and binary compound flooding (SP) sewage and oilfield water flooding sewage is that it contains polyacrylamide and surfactants as oil displacement agents. It is also because of the existence of oil displacement agents that polymer flooding and binary The properties of composite flooding (SP) sewage are very different from those of conventional water flooding sewage, which are manifested in: the suspended matter points in sewage are highly dispersed and stable, the emulsification is serious, and it has the characteristics of oil content, high suspended matter content, and small particle size; anionic polymer Severely interferes with the coagulation process of water purifiers, making the water purification effect of conventional water purifiers worse, and the dosage is greatly increased; when the polymer content is high, it often makes it difficult for the suspended solids content in the treated water to meet the injection water quality standard

[0003] Many scholars at home and abroad are committed to the research of polymer flooding and composite flooding sewage treatment technology, and have achieved many achievements and patents: CN201019006001.6 "A method for treating oilfield polymer flooding wastewater"; CN200910019040.X "A kind of oilfield polymer flooding CN201010105321.X "A method for treating produced water from ASP flooding"; CN200910019041.4 "A method for treating wastewater from ASP flooding"; CN200810104690.X)" Combined flooding production sewage air flotation and silicon removal integrated treatment process for reducing suspended solids”; the above-mentioned inventions all need to adjust the pH of the sewage to alkaline or strong alkaline, and add 3000mg / The concentration of L-11000mg / L is added with magnesium salt or magnesium salt as the main and sufficient treatment agent, and the purpose of purification is achieved through sufficient stirring, sedimentation and filtration. After these methods, the oil content and suspended solids content in the water are less than 20mg / L , the use of cheap and easy-to-obtain various magnesium salts as treatment agents reduces the treatment cost to a certain extent, but the dosage is large, the cost is still high, and a large amount of alkali needs to be added to the sewage, and the alkaline sewage is easy to reinject into the oil layer. lead to fouling of the injected layer

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