Oil-in-water emulsion oil displacement agent

Abstract

The invention discloses an oil-in-water emulsion oil displacement agent for crude oil chemical flooding for recovery efficiency improvement. The oil-in-water emulsion oil displacement agent is prepared from, by weight, 1-5 % of nano silica sol, 0.02-0.2% of octadecyl dimethylamine, 5-10% of 5 # white oil and the balance water and is prepared through mixing, wherein the particle size of the nano silica sol is 7-12 nm, and the weight percentage content sum of the components is 100%. The viscosity and stability of oil-in-water emulsion is improved by adding nano silica, the oil-in-water emulsion can improve the displacement efficiency of chemical flooding and also improve sweep efficiency and can improve the displacement efficiency by 30% or above based on water flooding by serving as the oil displacement agent for tertiary oil recovery.

Description

[0001] Technical field:

[0002] The invention relates to a chemical oil displacement agent for crude oil, in particular to an oil-in-water displacement system strengthened by nanoparticles, and belongs to the technical field of enhanced oil recovery.

[0003] Background technique:

[0004] Chemical flooding technology is the main method to further improve oil recovery after primary oil recovery (self-spraying production) and secondary oil recovery (water injection development) in my country's oilfields. There are two mechanisms for chemical flooding to increase oil recovery: one is to increase The viscosity of the oil system is used to increase the sweep coefficient, and the second is to increase the oil washing efficiency by reducing the oil-water interfacial tension and changing the wettability of the formation.

[0005] Although the indoor research and field application of chemical flooding have achieved good results in enhancing oil recovery (indoor tests show that chemical...