Corrosion inhibition scale-removing agent used for CO2 flooding as well as preparation method and use method of corrosion inhibition scale-removing agent

Abstract

The invention provides a corrosion inhibition scale-removing agent used for CO2 flooding as well as a preparation method and use method of the corrosion inhibition scale-removing agent. The corrosioninhibition scale-removing agent is composed of the following substances, in percentages by weight: 17-21% of benzoic acid thioureido imidazoline, 1-3% of benzoic acid phosphate thioureido imidazoline,9-13% of isopropanol, 7-11% of acetic acid, 11-15% of sodium polyepoxysuccinate, 3-7% of OP-10, 12-16% of quinoline quaternary ammonium, 3-7% of poly(sodium-styrennesulfonate), 5-9% of ethylenediaminetetraacetic acid disodium salt, 11-15% of diethylenetriaminepentaacetic acid pentasodium salt, 2-6% of N-dodecyl methylene bis-sec-ammonium salt, and the balance of water. The corrosion inhibition scale-removing agent provided by the invention overcomes the problem that a current corrosion inhibitor usually has a single corrosion inhibiting effect and a current scale inhibitor usually has a single scale inhibiting effect, can effectively play a corrosion inhibition effect while efficiently preventing scaling of oilfield water, and especially has a better scale-removing effect on barium strontium scale formed by formation water with high barium and strontium ions.

Description

technical field [0001] The invention belongs to the technical field of oilfield water treatment, in particular to a CO 2 Corrosion inhibitor and scale remover for oil displacement, preparation method and application method. Background technique [0002] At present, more than 70% of my country's newly discovered and discovered undeveloped crude oil reserves are low-permeability oil fields and hard-to-recover reserves. Such oil fields are difficult to develop economically and effectively, and the oil recovery rate is low. Field practice at home and abroad proves that CO 2 Oil flooding can greatly increase the recovery rate of low-permeability oilfields and the production rate of hard-to-recover reserves. Miscible oil flooding can increase oil recovery by more than 10%, and immiscible oil flooding can increase oil recovery by more than 7%. [0003] CO 2 Water injection is used for development before flooding, since the formation water is CaCl 2 Water type, high average sal...

AI Technical Summary

Problems solved by technology

[0005] At present, the application of corrosion inhibitors and scale inhibitors in oilfields can slow down the formation of downhole oilfield scale, but corrosion inhibitors and scale inhibitors only have anti-corrosion and anti-scale effects. The efficiency is limited. The scale accumulated in long-term production will aggravate the under-scale corrosion of the pipe string, which seriously affects the service life of the pipe string and the production efficiency of the oil field.