The application relates to the technical field of oilfield
sewage treatment, and particularly discloses a composite water
clarifying agent for oilfield
sewage treatment and a preparation method thereof. The composite water
clarifying agent for oilfield
sewage treatment is prepared from the following raw materials: double-modified
polyacrylamide, imidazoline
quaternary ammonium salt graft
copolymer, scale inhibitor, adsorbent, dodecyl dimethyl
betaine, coagulant aid and deionized water; the double-modified
polyacrylamide is obtained by double modification of 2,3-epoxypropyl trimethyl
ammonium chloride and a
hydrophobic monomer on
polyacrylamide; and the imidazoline
quaternary ammonium salt graft
copolymer is a graft
copolymer of imidazoline
quaternary ammonium salt,
acrylamide and
acrylamide-2-methylpropane
sulfonic acid. The composite water
clarifying agent can be used for treating high-salt and high-oil sewage generated in the middle and late stages of oilfield exploitation, has the advantages of
strong salt resistance, complete demulsification and good
flocculation effect, can efficiently remove oil and
suspended solids, ensures that the
effluent meets the standards, and meets the complex
sewage treatment requirements of oilfields.