	US 11,702,585 B2
	Tight oil reservoir CO₂flooding multi-scale channeling control system and preparation method
Daijun Du, Chengdu (CN); Huancai Fan, Chengdu (CN); Wanfen Pu, Chengdu (CN); Rui Liu, Chengdu (CN); Fayang Jin, Chengdu (CN); Lin Sun, Chengdu (CN); Binyang Zou, Chengdu (CN); and Bowen Chen, Chengdu (CN)
Assigned to Southwest Petroleum University, Chengdu (CN)
Filed by Southwest Petroleum University, Chengdu (CN)
Filed on Aug. 31, 2022, as Appl. No. 17/900,822.
Claims priority of application No. 202111304265.7 (CN), filed on Nov. 5, 2021.
Prior Publication US 2023/0146672 A1, May 11, 2023
Int. Cl. C09K 8/588 (2006.01); C09K 8/594 (2006.01)

CPC C09K 8/588 (2013.01) [C09K 8/594 (2013.01); C09K 2208/10 (2013.01)]

4 Claims

1. A tight oil reservoir CO₂flooding multi-scale channeling control system, comprising nanoscale CO₂responsive worm-like micelle system and micron-scale CO₂responsive dispersion gel;

wherein, in mass percent, the micron-scale CO₂responsive dispersion gel are prepared by cross-linking the following components:

acrylamide 15%-25%;

responsive monomer 3%-8%;

silane coupling agent modified hydroxylated multi-walled carbon nanotubes 0.05%-0.1%;

initiator 0.01%-0.1% of total monomer mass;

cross-linking agent 0.5%-2% of the total monomer mass; and

water, wherein the total mass percent of the components is 100%;

the preparation method of the micron-scale CO₂responsive dispersion gel is:

after the silane coupling agent modified hydroxylated multi-walled carbon nanotubes are dispersed uniformly in water by ultrasonic waves, under the condition of stirring speed of 300-500 r/min, the acrylamide, responsive monomer, initiator and cross-linking agent are respectively added to the solution; N₂is injected into the solution until the solution becomes viscous, and a thermometer is used to monitor the temperature change of the solution, until the temperature of the solution rises to a highest temperature when cooling down starts, the solution is kept in thermal insulation for 2-4 hours under the condition of the highest temperature of the solution to obtain a black gel; micron-scale CO₂responsive dispersion gel is obtained after granulation, drying and pulverization of the black gel;

wherein, the responsive monomer is N-methyl-N-vinylformamide, N,N-diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, or a combination thereof;

wherein, the nanoscale CO₂responsive worm-like micelle system is prepared by cross-linking the following components:

CO₂responsive monomer 30-90 mmol/L;

organic counter ion monomer 30-90 mmol/L; and

a solvent comprising water;

the preparation method of the nanoscale CO₂responsive worm-like micelle system is:

CO₂responsive monomer is completely dissolved in water to formulate CO₂responsive monomer solution, under the condition of stirring speed of 300-500 r/min, the organic counter ion monomer is added with the same amount of the CO₂responsive monomer to the CO₂responsive monomer solution, and the solution is stirred at room temperature to obtain uniform nano-scale CO₂responsive worm-like micelle system;

wherein the CO₂responsive monomer is N,N-dimethylcyclohexylamine, N,N-dimethylbenzylamine, N,N-dimethylbutylamine, tetramethylethylenediamine, trimethylamine, N,N-dimethyloleoaminde-propylamine, diethylenetriamine, cocoyl dimethyl tertiary amine, erucic acid amidopropyl dimethyl tertiary amine, or a combination thereof

the organic counter ion monomer is sodium p-styrenesulfonate, sodium dodecylbenzenesulfonate, sodium p-toluenesulfonate, sodium oleate, or a combination thereof.