Oil displacement emulsion stabilized by magnetic nanoparticles

Abstract

The invention relates to the technical field of oil-gas field development, and discloses an oil displacement emulsion stabilized by magnetic nanoparticles. The oil displacement emulsion aims to solvethe problems that thermal stability of an existing oil displacement emulsion is poor and oil-water separation is prone to occurring. The oil displacement emulsion is prepared from: modified magnetic nano Fe3O4@SiO2 particles, a surfactant and polymers. A preparation method comprises the steps that a, the modified magnetic nano Fe3O4@SiO2 particles, the surfactant, the polymers and deionized waterare mixed into an aqueous phase solution, and ultrasonic mixing is performed for 30-60 min to form a mixed solution; and b, an oil phase is added to the mixed solution, a rotation speed is homogenizedfor 10-15 min to obtain a uniformly mixed oil-water system, the oil-water system is allowed to stand at a room temperature for 24h-72h, and the excess oil phase and water phase are separated to obtain a finished product. The oil displacement emulsion stabilized by the magnetic nanoparticles has good stability under high temperature and high salt conditions, and the oil displacement emulsion can significantly improve the recovery ratio of low permeability oil reservoirs.

Description

technical field [0001] The invention relates to the technical field of oil and gas field development materials, in particular to an oil displacement emulsion stabilized by magnetic nanoparticles. Background technique [0002] Traditional emulsion flooding is to inject the emulsion formed by emulsifier (surfactant or surface-active polymer) and crude oil under high-speed stirring into the formation to displace the residual oil after water flooding. Laboratory and field practice shows that emulsion flooding can effectively reduce the residual oil in the formation, and the recovery rate can be increased by about 10%. However, due to the poor long-distance migration and thermal stability of traditional emulsions, they cannot be widely used in oil displacement. In recent years, due to the advancement of nanomaterial technology, a kind of oil displacement emulsion formed by nano solid particles as emulsifier has been developed. Patent No. CN201810462744.3, named as a composite em...

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Problems solved by technology

[0004] The purpose of the present invention is to overcome the problems of poor thermal stability and easy oil-water separation of the oil-displacement emulsion in the prior art, and provide an oil-displacement emulsion stabilized by magnetic nanoparticles, which has good stability under high-temperature and high-salt conditions. Oil displacement emulsion can significantly enhance the recovery of low permeability reservoirs

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