CN-115232249-B - Preparation method of in-situ phase-change gel profile control oil displacement agent

Abstract

The invention belongs to the field of oil extraction aids in oil fields, and relates to a preparation method of an in-situ phase-change gel profile control oil displacement agent. The invention particularly relates to a method for preparing an in-situ phase-change gel profile control oil displacement agent by using allyl urea, vinyl pyridine, acryloyloxyethyl trimethyl ammonium chloride, 2-acrylamide-2-methylpropanesulfonic acid, 2-acrylamido tetradecyl sulfonic acid and acrylamide as raw materials. The invention prepares a tetrapolymer by taking allyl urea, 2-acrylamide-tetradecyl sulfonic acid, 2-acrylamide-2-methylpropanesulfonic acid and acrylamide as raw materials according to the mol ratio of 1:1:5:25 through free radical initiation aqueous solution polymerization, prepares a terpolymer by taking 4-vinyl pyridine, acryloyloxyethyl trimethyl ammonium chloride and acrylamide as raw materials according to the mol ratio of 1:5:25 through free radical initiation aqueous solution polymerization, and then mixes the prepared two polymer solid powders according to the mol ratio of 1:1 to prepare the variable phase gel profile control oil displacement agent. The profile control oil displacement agent has stronger profile control water shutoff and oil displacement capacity and reliable preparation process.

Inventors

• MA JINHAI
• KONG SHULING

Assignees

• 青岛大学

Dates

Publication Date

20260505

Application Date

20220511

Claims (1)

1. 1. The preparation method of the in-situ phase-change gel profile control oil displacement agent is characterized by comprising the following steps of: (1) Weighing 0.02mol of allyl urea, 0.02mol of 2-acrylamido tetradecyl sulfonic acid, 0.1mol of 2-acrylamido-2-methylpropane sulfonic acid and 0.5mol of acrylamide, adding into a 200mL reaction bottle, adding 100mL of distilled water, stirring for dispersion and dissolution, regulating the pH value to 6.8 by using 40% sodium hydroxide, introducing nitrogen for 15 minutes, respectively dropwise adding 2mL of 0.5% potassium persulfate solution and 1mL of 0.5% sodium bisulfite solution, sealing the reaction bottle, heating to 38 ℃, carrying out heat preservation reaction for 3 hours to obtain transparent gel blocks, cooling to room temperature, cutting into small blocks, drying at 85 ℃ for 12 hours in a drying box, taking out, naturally cooling to room temperature in a dryer, crushing, and preserving in a sealed bag for standby; (2) Weighing 0.02mol of 4-vinylpyridine, 0.1mol of acryloyloxyethyl trimethyl ammonium chloride and 0.5mol of acrylamide, adding into a 200mL reaction bottle, adding 100mL of distilled water, stirring, dispersing and dissolving, regulating the pH value to 7.0 by using 30% HCl, introducing nitrogen for 15 minutes, respectively dropwise adding 2mL of 0.5% potassium persulfate solution and 1mL of 0.5% sodium bisulfite solution, sealing the reaction bottle, heating to 40 ℃, preserving heat for 3 hours to obtain pale yellow transparent gel blocks, cooling to room temperature, cutting into small blocks, drying at 85 ℃ for 12 hours in a drying box, taking out, naturally cooling to room temperature in a dryer, crushing, and preserving in a sealing bag for standby; (3) The solid powder stored in the sealed bag obtained in the step (1) and the solid powder stored in the sealed bag obtained in the step (2) are added into a mixer together, mixed for 10 minutes, taken out and put into the sealed bag for storage.

Description

Preparation method of in-situ phase-change gel profile control oil displacement agent Technical Field The invention belongs to the field of oil extraction aids in oil fields, and particularly relates to a method for preparing an in-situ phase-change gel profile control oil displacement agent from allyl urea, vinyl pyridine, acryloyloxyethyl trimethyl ammonium chloride, 2-acrylamide-2-methylpropanesulfonic acid, 2-acrylamido tetradecanesulfonic acid and acrylamide serving as raw materials. Background At present, polymer flooding has become one of the important technical means of stable production in the eastern field of China for many years, and polymer flooding technology has made a great contribution to the increase in oil field yield, but also has gradually developed a plurality of problems, wherein one of the most serious problems is that a large number of undegraded polyacrylamide appears in produced liquid along with the ditch connection of a production well and a polymer injection well, and the polymer molecules seriously interfere with crude oil dehydration, and bring great difficulty to sewage treatment, increase environmental protection cost and restrict crude oil production. Therefore, the active polymer gel profile control oil displacement agent which is self-assembled and phase-changed and dehydrated in situ in an oil layer can be developed to solve the actual production problem of the oil field. The in-situ phase change active gel prepared by taking allyl urea, 4-vinyl pyridine, acryloyloxyethyl trimethyl ammonium chloride, 2-acrylamide-2-methylpropanesulfonic acid, 2-acrylamido tetradecanesulfonic acid and acrylamide as raw materials can be automatically dehydrated, aggregated and phase-changed in the oil displacement process in an oil layer, so that polymer molecules are not present in produced liquid, crude oil is easy to dehydrate, and meanwhile, the environmental protection cost is reduced. The gel system has better oil displacement capability by taking the 2-acrylamide tetradecyl sulfonic acid as an active functional monomer, and the allyl urea, 4-vinyl pyridine and the acrylamide monomer can enable the gel system to have multiple hydrogen bond effects of carbonyl and amino, and the 2-acrylamide-2-methylpropanesulfonic acid and the acryloyloxyethyl trimethyl ammonium chloride generate intermolecular clustering and assembly through anion-cation electrostatic interaction, so that the gel phase is converted into solid gel blocks in situ in an oil layer after the oil displacement task is completed, and a profile control water shutoff effect is generated, so that the gel system has better profile control water shutoff and oil displacement capability as a whole. Disclosure of Invention The invention firstly uses allyl urea, 2-acrylamide tetradecyl sulfonic acid, 2-acrylamide-2-methylpropanesulfonic acid and acrylamide as raw materials to prepare four tetrapolymers by free radical initiation aqueous solution polymerization according to the mol ratio of 1:1:5:25, then uses 4-vinyl pyridine, acryloyloxyethyl trimethyl ammonium chloride and acrylamide as raw materials to prepare three terpolymers by free radical initiation aqueous solution polymerization according to the ratio of 1:5:25, and respectively cuts, dries and pulverizes the prepared colloid, then mixes the prepared two polymer solid powders according to the ratio of 1:1, and dissolves the mixture in water to prepare the variable phase gel profile control oil displacement agent. The profile control oil displacement agent has stronger profile control water plugging capability and oil displacement capability, and the preparation process is reliable, and the preparation method of the in-situ phase change gel profile control oil displacement agent is provided. Detailed Description Example 1 (1) Weighing 0.02mol of allyl urea, 0.02mol of 2-acrylamido tetradecyl sulfonic acid, 0.1mol of 2-acrylamido-2-methylpropane sulfonic acid and 0.5mol of acrylamide, adding into a 200mL reaction bottle, adding 100mL of distilled water, stirring for dispersion and dissolution, regulating the pH value to 6.8 by using 40% sodium hydroxide, introducing nitrogen for 15 minutes, respectively dropwise adding 2mL of 0.5% potassium persulfate solution and 1mL of 0.5% sodium bisulfite solution, sealing the reaction bottle, heating to 38 ℃, carrying out heat preservation reaction for 3 hours to obtain transparent gel blocks, cooling to room temperature, cutting into small blocks, drying at 85 ℃ for 12 hours in a drying box, taking out, naturally cooling to room temperature in a dryer, crushing, and preserving in a sealed bag for standby; (2) Weighing 0.02mol of 4-vinylpyridine, 0.1mol of acryloyloxyethyl trimethyl ammonium chloride and 0.5mol of acrylamide, adding into a 200mL reaction bottle, adding 100mL of distilled water, stirring, dispersing and dissolving, regulating the pH value to 7.0 by using 30% HCl, introducing nitrogen for 15 minutes, respectively dropwise