Preparation method of polymer weak gel deep profile control agent

Abstract

The invention relates to a preparation method of a polymer weak gel deep profile control agent. The preparation method comprises the following steps of preparing sodium carboxymethyl cellulose and distilled water into sodium carboxymethyl cellulose water solution of which the mass percentage is 1%-2%; adding acrylamide of which the mass is 2-8 times as great as that of the sodium carboxymethyl cellulose into the sodium carboxymethyl cellulose water solution, and then adding a cross-linking agent which accounts for 0.01%-2% of the total weight of the sodium carboxymethyl cellulose and the acrylamide; enabling nitrogen to enter into a closed system and isolating the air, and adding an initiating agent which accounts for 1%-2% of the total mass of the sodium carboxymethyl cellulose and the acrylamide; and discharging after carrying out constant-temperature reaction for 4-12 hours under the temperature of 30-60 DEG C. According to the preparation method disclosed by the invention, the acrylamide is grafted to the sodium carboxymethyl cellulose, polymer weal gel with a mesh structure is formed under the action of the initiating agent and the cross-linking agent, and a polymer weak gel system integrates the advantages of the sodium carboxymethyl cellulose and the acrylamide.

Description

technical field

[0001] The invention belongs to the technical field of oilfield chemistry and relates to a preparation method of a polymer weak gel deep profile control agent. technical background

[0002] At present, most oilfields on land in China are already in the period of high water-cut or ultra-high water-cut exploitation, and the pore structure of most oil layers has undergone great changes after long-term water injection or water flooding, and the heterogeneity has become more serious, and high-permeability channels have gradually formed in the oil layers Or large pores make the formation pressure field and streamline field form a fixed potential, forming a dominant water flow channel between oil and water wells, resulting in a "short circuit" of water flooding, and the injected water rushes into the oil well along the high permeability zone, resulting in an increase in the water content of the oil well. decline. For conventional cross-linked polymer profile contro...

Examples

Embodiment 1

[0032] Prepare 2.50 g of sodium carboxymethylcellulose (CMC) with a viscosity of 800-1200 mPa·s into a 1% solution with distilled water and stir evenly, then add 10.00 g of acrylamide and 0.0075 g of N,N'-methylene Base bisacrylamide, pass nitrogen into the system, add Na in turn 2 SO 3 0.0566g, (NH 4 ) 2 S 2 o 8 0.1065g, stir well and react in a constant temperature water bath at 40°C for 8 hours to form a gel.

[0033] Precipitate and separate the prepared polymer weak gel with ethanol solvent, dry to obtain a crude cross-linked polymer, extract the crude cross-linked polymer with acetone in a Soxhlet extractor for 10 hours to remove the homopolymer, and dry it in a vacuum to obtain Pure cross-linked polymer. Take the dried raw material of sodium carboxymethyl cellulose and purified polymer weak gel 2~3mg and 200~300mg of dry KBr powder and mix them in an agate mortar, fully grind until the particle diameter is less than 2μm, and use stainless steel Scoop 70-90mg into...

Embodiment 2

[0039] Prepare 2.50 g of sodium carboxymethylcellulose (CMC) with a viscosity of 800-1200 mPa·s into a 1% solution with distilled water and stir evenly, then add 10.00 g of acrylamide and 0.0063 g of N,N'-methylene Base bisacrylamide, pass nitrogen into the system, add Na in turn 2 SO 3 0.0666g, (NH 4 ) 2 S 2 o 8 0.1209g, stirred evenly and reacted in a constant temperature water bath at 30°C for 8 hours to form a gel.

[0040] The viscosity of the gel measured by NDJ-8S viscometer is 10520mPa·s, and the temperature and salt resistance properties are shown in the attached image 3 And attached Figure 5 shown.

Embodiment 3

[0042] Prepare 2.50 g of sodium carboxymethylcellulose (CMC) with a viscosity of 800-1200 mPa·s into a 2% solution with distilled water and stir evenly, then add 12.50 g of acrylamide and 0.0075 g of N,N'-methylene Base bisacrylamide, pass nitrogen into the system, add Na in turn 2 SO 3 0.0694g, (NH 4 ) 2 S 2 o 8 0.1255g, stir well and react in a constant temperature water bath at 40°C for 8 hours to form a gel.

[0043] The viscosity of the gel measured by NDJ-8S viscometer is 13280mPa·s, and the temperature and salt resistance properties are as follows: image 3 And attached Figure 5 shown.

technical field

[0001] The invention belongs to the technical field of oilfield chemistry and relates to a preparation method of a polymer weak gel deep profile control agent. technical background

[0002] At present, most oilfields on land in China are already in the period of high water-cut or ultra-high water-cut exploitation, and the pore structure of most oil layers has undergone great changes after long-term water injection or water flooding, and the heterogeneity has become more serious, and high-permeability channels have gradually formed in the oil layers Or large pores make the formation pressure field and streamline field form a fixed potential, forming a dominant water flow channel between oil and water wells, resulting in a "short circuit" of water flooding, and the injected water rushes into the oil well along the high permeability zone, resulting in an increase in the water content of the oil well. decline. For conventional cross-linked polymer profile contro...

Examples

Embodiment 1

[0032] Prepare 2.50 g of sodium carboxymethylcellulose (CMC) with a viscosity of 800-1200 mPa·s into a 1% solution with distilled water and stir evenly, then add 10.00 g of acrylamide and 0.0075 g of N,N'-methylene Base bisacrylamide, pass nitrogen into the system, add Na in turn 2 SO 3 0.0566g, (NH 4 ) 2 S 2 o 8 0.1065g, stir well and react in a constant temperature water bath at 40°C for 8 hours to form a gel.

[0033] Precipitate and separate the prepared polymer weak gel with ethanol solvent, dry to obtain a crude cross-linked polymer, extract the crude cross-linked polymer with acetone in a Soxhlet extractor for 10 hours to remove the homopolymer, and dry it in a vacuum to obtain Pure cross-linked polymer. Take the dried raw material of sodium carboxymethyl cellulose and purified polymer weak gel 2~3mg and 200~300mg of dry KBr powder and mix them in an agate mortar, fully grind until the particle diameter is less than 2μm, and use stainless steel Scoop 70-90mg into...

Embodiment 2

[0039] Prepare 2.50 g of sodium carboxymethylcellulose (CMC) with a viscosity of 800-1200 mPa·s into a 1% solution with distilled water and stir evenly, then add 10.00 g of acrylamide and 0.0063 g of N,N'-methylene Base bisacrylamide, pass nitrogen into the system, add Na in turn 2 SO 3 0.0666g, (NH 4 ) 2 S 2 o 8 0.1209g, stirred evenly and reacted in a constant temperature water bath at 30°C for 8 hours to form a gel.

[0040] The viscosity of the gel measured by NDJ-8S viscometer is 10520mPa·s, and the temperature and salt resistance properties are shown in the attached image 3 And attached Figure 5 shown.

Embodiment 3

[0042] Prepare 2.50 g of sodium carboxymethylcellulose (CMC) with a viscosity of 800-1200 mPa·s into a 2% solution with distilled water and stir evenly, then add 12.50 g of acrylamide and 0.0075 g of N,N'-methylene Base bisacrylamide, pass nitrogen into the system, add Na in turn 2 SO 3 0.0694g, (NH 4 ) 2 S 2 o 8 0.1255g, stir well and react in a constant temperature water bath at 40°C for 8 hours to form a gel.

[0043] The viscosity of the gel measured by NDJ-8S viscometer is 13280mPa·s, and the temperature and salt resistance properties are as follows: image 3 And attached Figure 5 shown.

Images