Instant polyacrylamide for offshore oil displacement and preparation method therefor

Abstract

An instant polyacrylamide for offshore oil displacement and a preparation method therefor, relating to the field of additives for oil extraction. The instant polyacrylamide for offshore oil displacement is obtained by copolymerizing an acrylamide aqueous solution, an acrylic acid aqueous solution, an N-vinyl pyrrolidone aqueous solution, a 2-acrylamide-2-methylpropanesulfonic acid aqueous solution and a modified monomer solution and then adding a cosolvent; the modified monomer is prepared from glycidyl ester containing a carbon-carbon double bond, diamino silicone oil and the like under an alkaline condition. The instant polyacrylamide for offshore oil displacement has the characteristics of high molecular weight, short dissolution time, high salinity resistance, shear resistance and the like, and is particularly suitable for offshore oil displacement.

Description

Instant-type polyacrylamide for offshore oil displacement and preparation method thereof Technical Field

[0001] The present invention relates to the field of additives for oil recovery, in particular to a quick-dissolving polyacrylamide for offshore oil recovery and a preparation method thereof. Background Art

[0002] Offshore oil fields are rich in resources and have enormous potential for exploitation. Polyacrylamide is used as an oil displacement agent in the oil extraction industry to increase the viscosity of injected water, improve the oil-water mobility ratio, and expand the swept volume, thereby increasing crude oil recovery.

[0003] When used for offshore oil recovery, polyacrylamide is typically formulated with fresh water and then diluted with seawater. The high mineralization of seawater, resulting from the presence of various metal ions, requires polyacrylamide for oil recovery to possess excellent salt tolerance. Furthermore, the molecular weight of polyacrylamide is a key factor in determining its effectiveness in oil recovery; higher molecular weight polyacrylamide is more beneficial for enhancing oil recovery. Therefore, polyacrylamide's high molecular weight and high salt tolerance play a key role in enhancing oil recovery.

[0004] Currently, to improve the molecular weight and salt tolerance of polyacrylamide, some researchers use acrylamide, acrylic acid, N-vinyl pyrrolidone, and quaternary ammonium salts as monomers, and select appropriate initiator systems, dosages, reaction temperatures, etc. to synthesize polyacrylamide with a molecular weight of up to 20 million. This polyacrylamide has both an ultra-high molecular weight and good salt tolerance. However, the dissolution time of this ultra-high molecular weight polyacrylamide is as long as 1 hour, which seriously affects oil recovery efficiency. Furthermore, during the dissolution and stirring process of the polyacrylamide, the polyacrylamide is inevitably subjected to shearing, and the ultra-high molecular weight polyacrylamide has poor shear resistance, which can easily cause molecular weight fracture and viscosity reduction, resulting in a decrease in the water-to-oil flow rate ratio, which is not conducive to improving crude oil recovery.

[0005] Summary of the Invention

[0006] In order to obtain a polyacrylamide suitable for offshore oil recovery that has high molecular weight, short dissolution time, high salt resistance and shear resistance, the present application provides a quick-dissolving polyacrylamide for offshore oil recovery and a preparation method thereof.

[0007] In the first aspect, the present application provides a method for preparing an instant polyacrylamide for offshore oil recovery using the following technical solution:

[0008] A method for preparing instant polyacrylamide for offshore oil displacement comprises the following steps:

[0009] Add 15-45 parts by weight of glycidyl ester containing a carbon-carbon double bond and 10-25 parts by weight of bisamino silicone oil to 500-1000 parts by weight of an alcohol solution, stir evenly, adjust the pH to 9-10 with alkali, and then heat to 30-50° C. for reaction to obtain a modified monomer solution;

[0010] 40-50 parts by weight of a 20-40% acrylamide aqueous solution, 10-15 parts by weight of a 10-30% acrylic acid aqueous solution, 5-10 parts by weight of a 0.3-0.8% N-vinyl pyrrolidone aqueous solution, 10-20 parts by weight of a 1-5% 2-acrylamide-2-methylpropanesulfonic acid aqueous solution, and 15-25 parts by weight of a modified monomer solution are uniformly mixed, 0.001-0.002 parts by weight of a shielding agent and 1-3 parts by weight of a chain transfer agent are added, the mixture is stirred uniformly, and then nitrogen is introduced for deoxygenation to obtain a mixed solution;

[0011] The temperature of the mixed solution is adjusted to (-2°C)-5°C. Under nitrogen protection, 3-5 parts by weight of an initiator aqueous solution with a mass concentration of 0.1%-0.3% is added dropwise to the mixed solution. After the initiator aqueous solution is added, the reaction is carried out for 4-8 hours, and then a co-solvent is added and stirred evenly. Then, the material is discharged, granulated, and dried to obtain polyacrylamide.

[0012] First, a modified monomer solution is prepared by reacting the epoxy group in the glycidyl ester containing a carbon-carbon double bond with the amino group in the bisamino silicone oil. Then, acrylamide, acrylic acid, N-vinyl pyrrolidone, 2-acrylamide-2-methylpropanesulfonic acid and the modified monomer in the modified monomer solution are subjected to multi-polymerization to obtain a polyacrylamide with high molecular weight, high stability, high salt resistance and shear resistance. This can prevent the problem of rapid viscosity drop of polyacrylamide after shearing or under high-salt conditions, so that the water-oil flow rate ratio will not drop rapidly, which is conducive to improving the recovery rate of crude oil.

[0013] Among them, acrylamide, acrylic acid, N-vinyl pyrrolidone and 2-acrylamide-2-methylpropanesulfonic acid are prepared into an aqueous solution of specific concentration, which is beneficial to improving the safety of the polyacrylamide production process and increasing the molecular weight of polyacrylamide. Before adding the initiator aqueous solution, the temperature of the mixed solution is adjusted to (-2°C)-5°C, which is beneficial to preventing implosion and the problem of local excessive temperature causing polyacrylamide chain scission, and is also beneficial to increasing the molecular weight of polyacrylamide.

[0014] In addition, the addition of a co-solvent causes the solvent to absorb water and expand, thereby creating micropores in the particles. Water is then "absorbed" into the particles through the capillary effect. This repeated absorption and expansion quickly disintegrates the intact solid polyacrylamide particles into fine particles or powder, thereby increasing the specific surface area and speeding up the dissolution rate. Due to the accelerated dissolution rate of polyacrylamide, the dissolution time of polyacrylamide is shortened, which is conducive to improving the recovery efficiency of crude oil.

[0015] Optionally, the molecular formula of the glycidyl ester containing a carbon-carbon double bond is CH2=CHCH2(OCH2CH2) n OCH2COOCH2CH(O)CH2, wherein the value of n ranges from 5 to 20.

[0016] Compared with glycidyl methacrylate, glycidyl ester containing carbon-carbon double bonds adopts the molecular formula CH2=CHCH2(OCH2CH2) n When the value of OCH2COOCH2CH(O)CH2 is within the range of 5-20 for glycidyl ester, the shear viscosity retention rate of polyacrylamide can reach more than 80%, and the viscosity retention rate after heat aging for one month is more than 80%, which can significantly improve the shear resistance, high temperature resistance and high salt resistance of polyacrylamide.

[0017] Optional. The value of n ranges from 8 to 12.

[0018] When the value of n is in the range of 8-12, it is beneficial to further improve the shear resistance, high temperature resistance and high salt resistance of polyacrylamide.

[0019] Optionally, the bisamino silicone oil is bisaminopropyl polydimethylsiloxane, the molecular formula of which is H2N(CH2)3Si(CH3)2O[Si(CH3)2O] m Si(CH3)2(CH2)3NH2, wherein the value of m ranges from 10 to 30.

[0020] The amino groups at both ends of bisaminopropyl polydimethylsiloxane react with the epoxy groups on a glycidyl ether containing a carbon-carbon double bond to produce a modified monomer. This modified monomer is then copolymerized with acrylamide, acrylic acid, N-vinyl pyrrolidone, and 2-acrylamido-2-methylpropanesulfonic acid to effectively improve the molecular weight, high-temperature resistance, and shear resistance of the polyacrylamide. When m is within the range of 10-30, the polyacrylamide's shear viscosity retention rate can reach over 80%, and the viscosity retention rate after one month of heat aging remains above 80%.

[0021] Optional. The value range of m is 15-20.

[0022] When the value of m is within the range of 15-20, it is beneficial to further improve the shear resistance, high temperature resistance and high salt resistance of polyacrylamide.

[0023] Optionally, in the modified monomer solution, the glycidyl ester containing a carbon-carbon double bond is 20-28 parts by weight, the bisamino silicone oil is 14-18 parts by weight, and the alcohol solution is 600-800 parts by weight.

[0024] When the amount of glycidyl ester containing a carbon-carbon double bond is within the range of 20-28 parts by weight, the amount of bisamino silicone oil is within the range of 14-18 parts by weight, and the amount of the alcohol solution is within the range of 600-800 parts by weight, the obtained modified monomer acrylamide is copolymerized with acrylic acid, N-vinyl pyrrolidone, and 2-acrylamide-2-methylpropanesulfonic acid, which is beneficial to further improve the shear resistance, high temperature resistance, and high salt resistance of the polyacrylamide.

[0025] Optionally, before adding the initiator solution, the temperature of the mixed solution is (-1°C)-1°C.

[0026] Before adding the initiator solution, the temperature of the mixed solution is within the range of (-1°C)-1°C, which is beneficial to further improve the shear resistance, high temperature resistance and high salt resistance of the polyacrylamide.

[0027] Optionally, the initiator aqueous solution is added in three times; the amount of the initiator aqueous solution added for the first time is 25-35wt% of the total amount of the initiator aqueous solution, and the addition speed is 0.05-0.1g / min; the amount of the initiator aqueous solution added for the second time is 40-50wt% of the total amount of the initiator aqueous solution, and the addition speed is 0.1-0.2g / min; the initiator aqueous solution is added for the third time at a speed of 0.2-0.5g / min, and the interval between the addition of two adjacent initiator aqueous solutions is 30-45min.

[0028] The initiator aqueous solution is added in multiple times and added slowly at first and then quickly, which is beneficial to further improve the stability of the high temperature resistance and high salt resistance of polyacrylamide.

[0029] Optionally, the initiator aqueous solution is prepared by preparing an initiator and water, and the initiator is selected from one or more of a water-soluble azo initiator and a persulfate initiator.

[0030] The water-soluble azo initiator is selected from any one or more of azobisisobutylamidine hydrochloride and azobisisobutylimidazoline hydrochloride.

[0031] The persulfate initiator is selected from any one or more of potassium persulfate, sodium persulfate, and ammonium persulfate.

[0032] Optionally, the cosolvent is selected from one or more of sodium carboxymethyl starch, sodium starch glycolate, polyvinyl pyrrolidone, and sodium carboxymethyl cellulose.

[0033] The above-mentioned co-solvent can expand by absorbing water, thereby producing micropores in the polyacrylamide particles, and "sucking" water into the particles through the capillary effect. By repeatedly absorbing water and expanding, the complete solid polyacrylamide particles will soon disintegrate into fine particles or powder, thereby increasing the specific surface area and improving the dissolution rate.

[0034] Optionally, the shielding agent is selected from any one of disodium ethylenediaminetetraacetate and sodium diethylenetriaminepentaacetate, or a combination of the two.

[0035] Optionally, the chain transfer agent is isopropyl alcohol or sodium formate.

[0036] In a second aspect, the present application provides a polyacrylamide prepared by any of the above-mentioned methods for preparing instant polyacrylamide for offshore oil recovery.

[0037] In summary, compared with the prior art, this application has at least the following beneficial effects:

[0038] 1. Acrylamide, acrylic acid, N-vinyl pyrrolidone, 2-acrylamide-2-methylpropanesulfonic acid and the modified monomer in the modified monomer solution are copolymerized to obtain polyacrylamide with high molecular weight, high stability, high salt resistance and shear resistance. This can prevent the problem of rapid viscosity loss of polyacrylamide after shearing or under high salt conditions, so that the water-oil flow rate ratio will not drop rapidly, which is conducive to improving crude oil recovery;

[0039] 2. The initiator aqueous solution is added in multiple times, and the addition method is slow at first and then fast, which is beneficial to further improve the stability of the high temperature resistance and high salt resistance of polyacrylamide. DETAILED DESCRIPTION

[0040] The present application is further described in detail below with reference to experiments.

[0041] Example

[0042] [Example 1]

[0043] A quick-dissolving polyacrylamide for offshore oil displacement, the preparation method of which comprises the following steps:

[0044] Preparation of modified monomer solution: Add 15 kg of glycidyl ester containing carbon-carbon double bonds and 10 kg of bisamino silicone oil to 500 kg of 20% isopropanol solution, stir evenly, adjust the pH to 9 with sodium hydroxide, and then heat to 40°C to react to obtain a modified monomer solution. The glycidyl ester containing carbon-carbon double bonds contains a polyether segment with the molecular formula CH2=CHCH2(OCH2CH2)n OCH2COOCH2CH(O)CH2, the value range of n is 5; bisamino silicone oil uses bisaminopropyl polydimethylsiloxane, the molecular formula is H2N(CH2)3Si(CH3)2O[Si(CH3)2O] m Si(CH3)2(CH2)3NH2, the value range of m is 10.

[0045] Preparation of a mixed solution: 40 kg of a 30% aqueous acrylamide solution, 10 kg of a 20% aqueous acrylic acid solution, 5 kg of a 0.5% aqueous N-vinylpyrrolidone solution, 20 kg of a 3% aqueous 2-acrylamido-2-methylpropanesulfonic acid solution, and 25 kg of the modified monomer solution were uniformly mixed. 0.001 kg of a shielding agent and 1 kg of a chain transfer agent were then added. The mixture was stirred uniformly, and nitrogen was then introduced for deoxygenation to obtain a mixed solution. Disodium ethylenediaminetetraacetic acid was used as the shielding agent, and sodium formate was used as the chain transfer agent.

[0046] Preparation of polyacrylamide: Adjust the temperature of the mixed solution to -2°C. Under nitrogen, add 3 kg of a 0.2% aqueous initiator solution dropwise at a rate of 0.15 g / min. After addition of the aqueous initiator solution, allow the mixture to react for 6 hours. Then, add a cosolvent and stir until uniform. The mixture is discharged, granulated, and dried to obtain polyacrylamide. The aqueous initiator solution is an aqueous ammonium persulfate solution, and the cosolvent is polyvinylpyrrolidone.

[0047] [Example 2]

[0048] A quick-dissolving polyacrylamide for offshore oil displacement, the preparation method of which comprises the following steps:

[0049] Preparation of modified monomer solution: Add 25 kg of glycidyl ester containing carbon-carbon double bonds and 16 kg of bisamino silicone oil to 700 kg of 20% isopropanol solution, stir evenly, adjust the pH to 9 with sodium hydroxide, and then heat to 40°C to react to obtain a modified monomer solution. The glycidyl ester containing carbon-carbon double bonds contains a polyether segment with the molecular formula CH2=CHCH2(OCH2CH2) n OCH2COOCH2CH(O)CH2, the value range of n is 5; bisamino silicone oil uses bisaminopropyl polydimethylsiloxane, the molecular formula is H2N(CH2)3Si(CH3)2O[Si(CH3)2O] m Si(CH3)2(CH2)3NH2, the value range of m is 10.

[0050] Preparation of a mixed solution: 40 kg of a 30% aqueous acrylamide solution, 10 kg of a 20% aqueous acrylic acid solution, 5 kg of a 0.5% aqueous N-vinylpyrrolidone solution, 20 kg of a 3% aqueous 2-acrylamido-2-methylpropanesulfonic acid solution, and 25 kg of the modified monomer solution were uniformly mixed. 0.001 kg of a shielding agent and 1 kg of a chain transfer agent were then added. The mixture was stirred uniformly, and nitrogen was then introduced for deoxygenation to obtain a mixed solution. Disodium ethylenediaminetetraacetic acid was used as the shielding agent, and sodium formate was used as the chain transfer agent.

[0051] Preparation of polyacrylamide: Adjust the temperature of the mixed solution to -2°C. Under nitrogen, add 3 kg of a 0.2% aqueous initiator solution dropwise at a rate of 0.15 g / min. After addition of the aqueous initiator solution, allow the mixture to react for 6 hours. Then, add a cosolvent and stir until uniform. The mixture is discharged, granulated, and dried to obtain polyacrylamide. The aqueous initiator solution is an aqueous ammonium persulfate solution, and the cosolvent is polyvinylpyrrolidone.

[0052] [Example 3]

[0053] A quick-dissolving polyacrylamide for offshore oil displacement, the preparation method of which comprises the following steps:

[0054] Preparation of modified monomer solution: Add 45 kg of glycidyl ester containing carbon-carbon double bonds and 25 kg of bisamino silicone oil to 1000 kg of 20% isopropanol solution, stir evenly, adjust the pH to 9 with sodium hydroxide, and then heat to 40°C to react to obtain a modified monomer solution. The glycidyl ester containing carbon-carbon double bonds contains a polyether segment with the molecular formula CH2=CHCH2(OCH2CH2) n OCH2COOCH2CH(O)CH2, the value range of n is 5; bisamino silicone oil uses bisaminopropyl polydimethylsiloxane, the molecular formula is H2N(CH2)3Si(CH3)2O[Si(CH3)2O] m Si(CH3)2(CH2)3NH2, the value range of m is 10.

[0055] Preparation of a mixed solution: 40 kg of a 30% aqueous acrylamide solution, 10 kg of a 20% aqueous acrylic acid solution, 5 kg of a 0.5% aqueous N-vinylpyrrolidone solution, 20 kg of a 3% aqueous 2-acrylamido-2-methylpropanesulfonic acid solution, and 25 kg of the modified monomer solution were uniformly mixed. 0.001 kg of a shielding agent and 1 kg of a chain transfer agent were then added. The mixture was stirred uniformly, and nitrogen was then introduced for deoxygenation to obtain a mixed solution. Disodium ethylenediaminetetraacetic acid was used as the shielding agent, and sodium formate was used as the chain transfer agent.

[0056] Preparation of polyacrylamide: Adjust the temperature of the mixed solution to -2°C. Under nitrogen, add 3 kg of a 0.2% aqueous initiator solution dropwise at a rate of 0.15 g / min. After addition of the aqueous initiator solution, allow the mixture to react for 6 hours. Then, add a cosolvent and stir until uniform. The mixture is discharged, granulated, and dried to obtain polyacrylamide. The aqueous initiator solution is an aqueous ammonium persulfate solution, and the cosolvent is polyvinylpyrrolidone.

[0057] [Example 4]

[0058] A quick-dissolving polyacrylamide for offshore oil displacement, the preparation method of which comprises the following steps:

[0059] Preparation of modified monomer solution: Add 25 kg of glycidyl ester containing carbon-carbon double bonds and 16 kg of bisamino silicone oil to 700 kg of 20% isopropanol solution, stir evenly, adjust the pH to 9 with sodium hydroxide, and then heat to 40°C to react to obtain a modified monomer solution. The glycidyl ester containing carbon-carbon double bonds contains a polyether segment with the molecular formula CH2=CHCH2(OCH2CH2) n OCH2COOCH2CH(O)CH2, the value range of n is 5; bisamino silicone oil uses bisaminopropyl polydimethylsiloxane, the molecular formula is H2N(CH2)3Si(CH3)2O[Si(CH3)2O] m Si(CH3)2(CH2)3NH2, the value range of m is 10.

[0060] Preparation of a mixed solution: 45 kg of a 30% aqueous acrylamide solution, 12.5 kg of a 20% aqueous acrylic acid solution, 7.5 kg of a 0.5% aqueous N-vinylpyrrolidone solution, 15 kg of a 3% aqueous 2-acrylamido-2-methylpropanesulfonic acid solution, and 20 kg of the modified monomer solution were uniformly mixed. 0.0015 kg of a shielding agent and 2 kg of a chain transfer agent were then added. The mixture was stirred uniformly, and nitrogen was then introduced for deoxygenation to obtain a mixed solution. Disodium ethylenediaminetetraacetic acid was used as the shielding agent, and sodium formate was used as the chain transfer agent.

[0061] Preparation of polyacrylamide: Adjust the temperature of the mixed solution to -2°C. Under nitrogen, add 4 kg of a 0.2% aqueous initiator solution dropwise at a rate of 0.15 g / min. After addition of the aqueous initiator solution, allow to react for 6 hours. Then, add a cosolvent and stir until uniform. Then, discharging, granulating, and drying to obtain polyacrylamide. The aqueous initiator solution is an aqueous ammonium persulfate solution, and the cosolvent is polyvinylpyrrolidone.

[0062] [Example 5]

[0063] A quick-dissolving polyacrylamide for offshore oil displacement, the preparation method of which comprises the following steps:

[0064] Preparation of modified monomer solution: Add 25 kg of glycidyl ester containing carbon-carbon double bonds and 16 kg of bisamino silicone oil to 700 kg of 20% isopropanol solution, stir evenly, adjust the pH to 9 with sodium hydroxide, and then heat to 40°C to react to obtain a modified monomer solution. The glycidyl ester containing carbon-carbon double bonds contains a polyether segment with the molecular formula CH2=CHCH2(OCH2CH2) n OCH2COOCH2CH(O)CH2, the value range of n is 5; bisamino silicone oil uses bisaminopropyl polydimethylsiloxane, the molecular formula is H2N(CH2)3Si(CH3)2O[Si(CH3)2O] m Si(CH3)2(CH2)3NH2, the value range of m is 10.

[0065] Preparation of a mixed solution: 50 kg of a 30% aqueous acrylamide solution, 15 kg of a 20% aqueous acrylic acid solution, 10 kg of a 0.5% aqueous N-vinylpyrrolidone solution, 10 kg of a 3% aqueous 2-acrylamido-2-methylpropanesulfonic acid solution, and 15 kg of a modified monomer solution were uniformly mixed. 0.002 kg of a shielding agent and 3 kg of a chain transfer agent were then added. The mixture was stirred uniformly, and nitrogen was then introduced for deoxygenation to obtain a mixed solution. Disodium ethylenediaminetetraacetic acid was used as the shielding agent, and sodium formate was used as the chain transfer agent.

[0066] Preparation of polyacrylamide: Adjust the temperature of the mixed solution to -2°C. Under nitrogen, add 5 kg of a 0.2% aqueous initiator solution dropwise at a rate of 0.15 g / min. After addition of the aqueous initiator solution, allow to react for 6 hours. Then, add a cosolvent and stir evenly. Then, discharging, granulating, and drying to obtain polyacrylamide. The aqueous initiator solution is an aqueous ammonium persulfate solution, and the cosolvent is polyvinylpyrrolidone.

[0067] [Example 6]

[0068] A quick-dissolving polyacrylamide for offshore oil displacement, the preparation method of which comprises the following steps:

[0069] Preparation of modified monomer solution: Add 25 kg of glycidyl ester containing carbon-carbon double bonds and 16 kg of bisamino silicone oil to 700 kg of 20% isopropanol solution, stir evenly, adjust the pH to 9 with sodium hydroxide, and then heat to 40°C to react to obtain a modified monomer solution. The glycidyl ester containing carbon-carbon double bonds contains a polyether segment with the molecular formula CH2=CHCH2(OCH2CH2) nOCH2COOCH2CH(O)CH2, the value range of n is 10; bisamino silicone oil uses bisaminopropyl polydimethylsiloxane, the molecular formula is H2N(CH2)3Si(CH3)2O[Si(CH3)2O] m Si(CH3)2(CH2)3NH2, the value range of m is 10.

[0070] Preparation of a mixed solution: 45 kg of a 30% aqueous acrylamide solution, 12.5 kg of a 20% aqueous acrylic acid solution, 7.5 kg of a 0.5% aqueous N-vinylpyrrolidone solution, 15 kg of a 3% aqueous 2-acrylamido-2-methylpropanesulfonic acid solution, and 20 kg of the modified monomer solution were uniformly mixed. 0.0015 kg of a shielding agent and 2 kg of a chain transfer agent were then added. The mixture was stirred uniformly, and nitrogen was then introduced for deoxygenation to obtain a mixed solution. Disodium ethylenediaminetetraacetic acid was used as the shielding agent, and sodium formate was used as the chain transfer agent.

[0071] Preparation of polyacrylamide: Adjust the temperature of the mixed solution to -2°C. Under nitrogen, add 4 kg of a 0.2% aqueous initiator solution dropwise at a rate of 0.15 g / min. After addition of the aqueous initiator solution, allow to react for 6 hours. Then, add a cosolvent and stir until uniform. Then, discharging, granulating, and drying to obtain polyacrylamide. The aqueous initiator solution is an aqueous ammonium persulfate solution, and the cosolvent is polyvinylpyrrolidone.

[0072] [Example 7]

[0073] A quick-dissolving polyacrylamide for offshore oil displacement, the preparation method of which comprises the following steps:

[0074] Preparation of modified monomer solution: Add 25 kg of glycidyl ester containing carbon-carbon double bonds and 16 kg of bisamino silicone oil to 700 kg of 20% isopropanol solution, stir evenly, adjust the pH to 9 with sodium hydroxide, and then heat to 40°C to react to obtain a modified monomer solution. The glycidyl ester containing carbon-carbon double bonds contains a polyether segment with the molecular formula CH2=CHCH2(OCH2CH2) n OCH2COOCH2CH(O)CH2, the value range of n is 20; bisamino silicone oil uses bisaminopropyl polydimethylsiloxane, the molecular formula is H2N(CH2)3Si(CH3)2O[Si(CH3)2O] m Si(CH3)2(CH2)3NH2, the value range of m is 10.

[0075] Preparation of a mixed solution: 45 kg of a 30% aqueous acrylamide solution, 12.5 kg of a 20% aqueous acrylic acid solution, 7.5 kg of a 0.5% aqueous N-vinylpyrrolidone solution, 15 kg of a 3% aqueous 2-acrylamido-2-methylpropanesulfonic acid solution, and 20 kg of the modified monomer solution were uniformly mixed. 0.0015 kg of a shielding agent and 2 kg of a chain transfer agent were then added. The mixture was stirred uniformly, and nitrogen was then introduced for deoxygenation to obtain a mixed solution. Disodium ethylenediaminetetraacetic acid was used as the shielding agent, and sodium formate was used as the chain transfer agent.

[0076] Preparation of polyacrylamide: Adjust the temperature of the mixed solution to -2°C. Under nitrogen, add 4 kg of a 0.2% aqueous initiator solution dropwise at a rate of 0.15 g / min. After addition of the aqueous initiator solution, allow to react for 6 hours. Then, add a cosolvent and stir until uniform. Then, discharging, granulating, and drying to obtain polyacrylamide. The aqueous initiator solution is an aqueous ammonium persulfate solution, and the cosolvent is polyvinylpyrrolidone.

[0077] [Example 8]

[0078] A quick-dissolving polyacrylamide for offshore oil displacement, the preparation method of which comprises the following steps:

[0079] Preparation of modified monomer solution: Add 25 kg of glycidyl ester containing carbon-carbon double bonds and 16 kg of bisamino silicone oil to 700 kg of 20% isopropanol solution, stir evenly, adjust the pH to 9 with sodium hydroxide, and then heat to 40°C to react to obtain a modified monomer solution. The glycidyl ester containing carbon-carbon double bonds contains a polyether segment with the molecular formula CH2=CHCH2(OCH2CH2) n OCH2COOCH2CH(O)CH2, the value range of n is 10; bisamino silicone oil uses bisaminopropyl polydimethylsiloxane, the molecular formula is H2N(CH2)3Si(CH3)2O[Si(CH3)2O] m Si(CH3)2(CH2)3NH2, the value range of m is 18.

[0080] Preparation of a mixed solution: 45 kg of a 30% aqueous acrylamide solution, 12.5 kg of a 20% aqueous acrylic acid solution, 7.5 kg of a 0.5% aqueous N-vinylpyrrolidone solution, 15 kg of a 3% aqueous 2-acrylamido-2-methylpropanesulfonic acid solution, and 20 kg of the modified monomer solution were uniformly mixed. 0.0015 kg of a shielding agent and 2 kg of a chain transfer agent were then added. The mixture was stirred uniformly, and nitrogen was then introduced for deoxygenation to obtain a mixed solution. Disodium ethylenediaminetetraacetic acid was used as the shielding agent, and sodium formate was used as the chain transfer agent.

[0081] Preparation of polyacrylamide: Adjust the temperature of the mixed solution to -2°C. Under nitrogen, add 4 kg of a 0.2% aqueous initiator solution dropwise at a rate of 0.15 g / min. After addition of the aqueous initiator solution, allow to react for 6 hours. Then, add a cosolvent and stir until uniform. Then, discharging, granulating, and drying to obtain polyacrylamide. The aqueous initiator solution is an aqueous ammonium persulfate solution, and the cosolvent is polyvinylpyrrolidone.

[0082] [Example 9]

[0083] A quick-dissolving polyacrylamide for offshore oil displacement, the preparation method of which comprises the following steps:

[0084] Preparation of modified monomer solution: Add 25 kg of glycidyl ester containing carbon-carbon double bonds and 16 kg of bisamino silicone oil to 700 kg of 20% isopropanol solution, stir evenly, adjust the pH to 9 with sodium hydroxide, and then heat to 40°C to react to obtain a modified monomer solution. The glycidyl ester containing carbon-carbon double bonds contains a polyether segment with the molecular formula CH2=CHCH2(OCH2CH2) n OCH2COOCH2CH(O)CH2, the value range of n is 10; bisamino silicone oil uses bisaminopropyl polydimethylsiloxane, the molecular formula is H2N(CH2)3Si(CH3)2O[Si(CH3)2O] m Si(CH3)2(CH2)3NH2, the value range of m is 30.

[0085] Preparation of a mixed solution: 45 kg of a 30% aqueous acrylamide solution, 12.5 kg of a 20% aqueous acrylic acid solution, 7.5 kg of a 0.5% aqueous N-vinylpyrrolidone solution, 15 kg of a 3% aqueous 2-acrylamido-2-methylpropanesulfonic acid solution, and 20 kg of the modified monomer solution were uniformly mixed. 0.0015 kg of a shielding agent and 2 kg of a chain transfer agent were then added. The mixture was stirred uniformly, and nitrogen was then introduced for deoxygenation to obtain a mixed solution. Disodium ethylenediaminetetraacetic acid was used as the shielding agent, and sodium formate was used as the chain transfer agent.

[0086] Preparation of polyacrylamide: Adjust the temperature of the mixed solution to -2°C. Under nitrogen, add 4 kg of a 0.2% aqueous initiator solution dropwise at a rate of 0.15 g / min. After addition of the aqueous initiator solution, allow to react for 6 hours. Then, add a cosolvent and stir until uniform. Then, discharging, granulating, and drying to obtain polyacrylamide. The aqueous initiator solution is an aqueous ammonium persulfate solution, and the cosolvent is polyvinylpyrrolidone.

[0087] [Example 10]

[0088] A quick-dissolving polyacrylamide for offshore oil displacement, the preparation method of which comprises the following steps:

[0089] Preparation of modified monomer solution: Add 25 kg of glycidyl ester containing carbon-carbon double bonds and 16 kg of bisamino silicone oil to 700 kg of 20% isopropanol solution, stir evenly, adjust the pH to 9 with sodium hydroxide, and then heat to 40°C to react to obtain a modified monomer solution. The glycidyl ester containing carbon-carbon double bonds contains a polyether segment with the molecular formula CH2=CHCH2(OCH2CH2) n OCH2COOCH2CH(O)CH2, the value range of n is 10; bisamino silicone oil uses bisaminopropyl polydimethylsiloxane, the molecular formula is H2N(CH2)3Si(CH3)2O[Si(CH3)2O] m Si(CH3)2(CH2)3NH2, the value range of m is 18.

[0090] Preparation of a mixed solution: 45 kg of a 30% aqueous acrylamide solution, 12.5 kg of a 20% aqueous acrylic acid solution, 7.5 kg of a 0.5% aqueous N-vinylpyrrolidone solution, 15 kg of a 3% aqueous 2-acrylamido-2-methylpropanesulfonic acid solution, and 20 kg of the modified monomer solution were uniformly mixed. 0.0015 kg of a shielding agent and 2 kg of a chain transfer agent were then added. The mixture was stirred uniformly, and nitrogen was then introduced for deoxygenation to obtain a mixed solution. Disodium ethylenediaminetetraacetic acid was used as the shielding agent, and sodium formate was used as the chain transfer agent.

[0091] Preparation of polyacrylamide: Adjust the temperature of the mixed solution to -2°C, and under nitrogen protection, add 4 kg of 0.2% initiator aqueous solution to the mixed solution;

[0092] The initiator aqueous solution was added in three portions; the amount of the initiator aqueous solution added for the first time was 30 wt % of the total amount of the initiator aqueous solution, and the addition rate was 0.05 g / min; the amount of the initiator aqueous solution added for the second time was 45 wt % of the total amount of the initiator aqueous solution, and the addition rate was 0.15 g / min; the remaining initiator aqueous solution was added for the third time, and the addition rate of the initiator aqueous solution for the third time was 0.4 g / min. The interval between the two adjacent additions of the initiator aqueous solution was 45 min;

[0093] After the addition of the initiator aqueous solution, the mixture was reacted for 6 hours, and then a cosolvent was added and stirred evenly, followed by granulation and drying to obtain polyacrylamide. The initiator aqueous solution was an ammonium persulfate aqueous solution, and the cosolvent was polyvinyl pyrrolidone.

[0094] [Example 11]

[0095] A quick-dissolving polyacrylamide for offshore oil displacement, the preparation method of which comprises the following steps:

[0096] Preparation of modified monomer solution: Add 25 kg of glycidyl ester containing carbon-carbon double bonds and 16 kg of bisamino silicone oil to 700 kg of 20% isopropanol solution, stir evenly, adjust the pH to 9 with sodium hydroxide, and then heat to 40°C to react to obtain a modified monomer solution. The glycidyl ester containing carbon-carbon double bonds contains a polyether segment with the molecular formula CH2=CHCH2(OCH2CH2) n OCH2COOCH2CH(O)CH2, the value range of n is 10; bisamino silicone oil uses bisaminopropyl polydimethylsiloxane, the molecular formula is H2N(CH2)3Si(CH3)2O[Si(CH3)2O] m Si(CH3)2(CH2)3NH2, the value range of m is 18.

[0097] Preparation of a mixed solution: 45 kg of a 30% aqueous acrylamide solution, 12.5 kg of a 20% aqueous acrylic acid solution, 7.5 kg of a 0.5% aqueous N-vinylpyrrolidone solution, 15 kg of a 3% aqueous 2-acrylamido-2-methylpropanesulfonic acid solution, and 20 kg of the modified monomer solution were uniformly mixed. 0.0015 kg of a shielding agent and 2 kg of a chain transfer agent were then added. The mixture was stirred uniformly, and nitrogen was then introduced for deoxygenation to obtain a mixed solution. Disodium ethylenediaminetetraacetic acid was used as the shielding agent, and sodium formate was used as the chain transfer agent.

[0098] Preparation of polyacrylamide: Adjust the temperature of the mixed solution to -2°C, and under nitrogen protection, add 4 kg of 0.2% initiator aqueous solution to the mixed solution;

[0099] The initiator aqueous solution was added in three portions; the amount of the initiator aqueous solution added for the first time was 30 wt % of the total amount of the initiator aqueous solution, and the addition rate was 0.15 g / min; the amount of the initiator aqueous solution added for the second time was 45 wt % of the total amount of the initiator aqueous solution, and the addition rate was 0.15 g / min; the remaining initiator aqueous solution was added for the third time, and the addition rate of the initiator aqueous solution for the third time was 0.15 g / min. The interval between the two adjacent additions of the initiator aqueous solution was 45 min;

[0100] After the addition of the initiator aqueous solution, the mixture was reacted for 6 hours, and then a cosolvent was added and stirred evenly, followed by granulation and drying to obtain polyacrylamide. The initiator aqueous solution was an ammonium persulfate aqueous solution, and the cosolvent was polyvinyl pyrrolidone.

[0101] [Example 12]

[0102] A quick-dissolving polyacrylamide for offshore oil displacement, the preparation method of which comprises the following steps:

[0103] Preparation of modified monomer solution: Add 25 kg of glycidyl ester containing carbon-carbon double bonds and 16 kg of bisamino silicone oil to 700 kg of 20% isopropanol solution, stir evenly, adjust the pH to 9 with sodium hydroxide, and then heat to 40°C to react to obtain a modified monomer solution. The glycidyl ester containing carbon-carbon double bonds contains a polyether segment with the molecular formula CH2=CHCH2(OCH2CH2) n OCH2COOCH2CH(O)CH2, the value range of n is 10; bisamino silicone oil uses bisaminopropyl polydimethylsiloxane, the molecular formula is H2N(CH2)3Si(CH3)2O[Si(CH3)2O] m Si(CH3)2(CH2)3NH2, the value range of m is 18.

[0104] Preparation of a mixed solution: 45 kg of a 30% aqueous acrylamide solution, 12.5 kg of a 20% aqueous acrylic acid solution, 7.5 kg of a 0.5% aqueous N-vinylpyrrolidone solution, 15 kg of a 3% aqueous 2-acrylamido-2-methylpropanesulfonic acid solution, and 20 kg of the modified monomer solution were uniformly mixed. 0.0015 kg of a shielding agent and 2 kg of a chain transfer agent were then added. The mixture was stirred uniformly, and nitrogen was then introduced for deoxygenation to obtain a mixed solution. Disodium ethylenediaminetetraacetic acid was used as the shielding agent, and sodium formate was used as the chain transfer agent.

[0105] Preparation of polyacrylamide: Adjust the temperature of the mixed solution to -2°C, and under nitrogen protection, add 4 kg of 0.2% initiator aqueous solution to the mixed solution;

[0106] The initiator aqueous solution was added in three times; the amount of the initiator aqueous solution added for the first time was 30 wt % of the total amount of the initiator aqueous solution, and the addition rate was 0.4 g / min; the amount of the initiator aqueous solution added for the second time was 45 wt % of the total amount of the initiator aqueous solution, and the addition rate was 0.15 g / min; the remaining initiator aqueous solution was added for the third time, and the addition rate of the initiator aqueous solution for the third time was 0.05 g / min. The interval between the two adjacent additions of the initiator aqueous solution was 45 min;

[0107] After the addition of the initiator aqueous solution, the mixture was reacted for 6 hours, and then a cosolvent was added and stirred evenly, followed by granulation and drying to obtain polyacrylamide. The initiator aqueous solution was an ammonium persulfate aqueous solution, and the cosolvent was polyvinyl pyrrolidone.

[0108] Comparative Example

[0109] [Comparative Example 1]

[0110] A quick-dissolving polyacrylamide for offshore oil recovery is different from Example 1 in that the modified monomer solution is different. In this comparative example, the preparation process of the modified monomer solution is as follows:

[0111] 15 kg of glycidyl ester containing carbon-carbon double bonds and 10 kg of polydimethylsiloxane with a viscosity of 500 cp were added to 500 kg of 20% isopropanol solution, stirred evenly, and then the pH was adjusted to 9 with sodium hydroxide. The solution was then heated to 40°C for reaction to obtain a modified monomer solution. The glycidyl ester containing carbon-carbon double bonds contained a polyether segment with the molecular formula CH2=CHCH2(OCH2CH2). n OCH2COOCH2CH(O)CH2, the value range of n is 5.

[0112] [Comparative Example 2]

[0113] A quick-dissolving polyacrylamide for offshore oil recovery is different from Example 1 in that the modified monomer solution is different. In this comparative example, the preparation process of the modified monomer solution is as follows:

[0114] Add 15 kg of glycidol and 10 kg of bisamino silicone oil to 500 kg of 20% isopropyl alcohol solution, stir evenly, adjust the pH to 9 with sodium hydroxide, and then heat to 40°C to react to obtain a modified monomer solution. The bisamino silicone oil is bisaminopropyl polydimethylsiloxane, with the molecular formula H2N(CH2)3Si(CH3)2O[Si(CH3)2O] m Si(CH3)2(CH2)3NH2, the value range of m is 10.

[0115] [Comparative Example 3]

[0116] A quick-dissolving polyacrylamide for offshore oil recovery is different from Example 1 in that the modified monomer solution is different. In this comparative example, the preparation process of the modified monomer solution is as follows:

[0117] 15 kg of glycidyl ester containing carbon-carbon double bonds and 10 kg of bisamino silicone oil were added to 500 kg of 20% isopropanol solution, stirred evenly, and then heated to 40 ° C to react to obtain a modified monomer solution. Among them, the glycidyl ester containing carbon-carbon double bonds contains a polyether segment with the molecular formula CH2=CHCH2(OCH2CH2) n OCH2COOCH2CH(O)CH2, the value range of n is 5; bisamino silicone oil uses bisaminopropyl polydimethylsiloxane, the molecular formula is H2N(CH2)3Si(CH3)2O[Si(CH3)2O] m Si(CH3)2(CH2)3NH2, the value range of m is 10.

[0118] [Comparative Example 4]

[0119] A quick-dissolving polyacrylamide for offshore oil recovery, which differs from Example 1 in that the mixed solution is different. In this comparative example, the mixed solution is prepared as follows:

[0120] 40 kg of a 30% aqueous acrylamide solution, 25 kg of a 20% aqueous acrylic acid solution, 20 kg of a 0.5% aqueous N-vinylpyrrolidone solution, 5 kg of a 3% aqueous 2-acrylamide-2-methylpropanesulfonic acid solution, and 10 kg of a modified monomer solution were uniformly mixed. 0.001 kg of a shielding agent and 1 kg of a chain transfer agent were then added, stirred uniformly, and nitrogen was introduced for deoxygenation to obtain a mixed solution. The shielding agent was disodium ethylenediaminetetraacetic acid, and the chain transfer agent was sodium formate.

[0121] Performance testing

[0122] 1. Molecular weight: Measured according to Section 6.13 of Q / SH 0237-2008 and recorded in Table 1 below.

[0123] 2. Dissolution time: Test according to GB / T 12005.8-1989, determination method for dissolution rate of powdered polyacrylamide, and record the results in Table 1 below.

[0124] 3. Residual acrylamide content: Detect according to Section 6.10 of Q / SH 0237-2008 and record in Table 1 below.

[0125] 4. Shear viscosity retention rate: The test was conducted in accordance with Section 6.8 of Q / SH 0237-2008, using brine II as the brine. The results are recorded in Table 2 below.

[0126] 5. Heat aging viscosity retention rate: The test was conducted in accordance with Section 6.12 of Q / SH 0237-2008, wherein the brine used was brine II, the experimental temperature was 80°C, and the heat aging times were 7 days and 1 month, respectively, and are recorded in Table 2 below.

[0127] Table 1

[0128] Combining Examples 1-12 with the data in Table 1, it can be seen that the molecular weight of the polyacrylamide prepared in this application is close to 20 million, and the dissolution time is within 10 minutes, which allows rapid dissolution, and does not affect oil recovery efficiency due to the slow dissolution rate of the polyacrylamide. In addition, the residual acrylamide monomer in the polyacrylamide prepared in this application is less than 0.1%, and the safety performance is good. Among them, the polyacrylamide prepared in Example 10 has the least residual acrylamide, indicating that the initiator aqueous solution is added in a multi-step manner, and the use of a slow-to-fast dropwise addition method can effectively reduce the residual acrylamide in the polyacrylamide.

[0129] Table 2

[0130] Combining Example 1 with Comparative Examples 1-3 and the data in Table 2, it can be seen that the polyacrylamide obtained by copolymerizing a modified monomer solution obtained by reacting a glycidyl ester containing a carbon-carbon double bond with a bisamino silicone oil in an environment with a pH of 9-10 with acrylamide, acrylic acid, N-vinyl pyrrolidone and 2-acrylamide-2-methylpropanesulfonic acid has excellent shear resistance, high temperature resistance and high salt resistance.

[0131] Combining Example 1 with Comparative Example 4 and the data in Table 2, it can be seen that the ratio of the comonomers affects the shear resistance, high temperature resistance and high salt resistance of polyacrylamide.

[0132] In combination with Examples 1-3 and the data in Table 2, it can be seen that when the glycidyl ester containing a carbon-carbon double bond is in the range of 20-28 parts by weight, the bisamino silicone oil is in the range of 14-18 parts by weight, and the alcohol solution is in the range of 600-800 parts by weight, the resulting modified monomer acrylamide is copolymerized with acrylic acid, N-vinyl pyrrolidone and 2-acrylamide-2-methylpropanesulfonic acid, which is beneficial to further improve the shear resistance, high temperature resistance and high salt resistance of polyacrylamide.

[0133] Combining Example 4 with Examples 6-9 and the data in Table 2, it can be seen that the glycidyl ester containing a carbon-carbon double bond has the molecular formula CH2=CHCH2(OCH2CH2) n When the glycidyl ester of OCH2COOCH2CH(O)CH2 is used, the value of n in the range of 8-12 is more conducive to improving the shear resistance, high temperature resistance and high salt resistance of polyacrylamide. In addition, the diamino silicone oil is selected with the molecular formula H2N(CH2)3Si(CH3)2O[Si(CH3)2O] m When the bisaminopropyl polydimethylsiloxane of Si(CH3)2(CH2)3NH2 is prepared, a value of m in the range of 15-20 is more conducive to improving the shear resistance, high temperature resistance and high salt resistance of polyacrylamide.

[0134] Combining Example 8 with Examples 10-11 and the data in Table 2, it can be seen that the viscosity retention stability of the polyacrylamide in Example 10 under high temperature and high salt conditions is significantly higher than that of Examples 8-9 and Example 11, indicating that the initiator aqueous solution is added in a multi-step manner and a slow-to-fast dripping method is adopted, which is beneficial to further improve the stability of the high temperature resistance and high salt resistance of the polyacrylamide.

[0135] This specific implementation manner is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the specific implementation manner as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A method for preparing instant polyacrylamide for offshore oil displacement, characterized in that: The following steps are involved: 15-45 parts by weight of glycidyl ester containing carbon-carbon double bonds and 10-25 parts by weight of bisamino silicone oil are added to 500-1000 parts by weight of an alcohol solution, stirred evenly, adjusted the pH to 9-10 with alkali, and then heated to 30-50° C. for reaction to obtain a modified monomer solution; 40-50 parts by weight of an acrylamide aqueous solution with a mass concentration of 20-40%, 10-15 parts by weight of an acrylic acid aqueous solution with a mass concentration of 10-30%, 5-10 parts by weight of an N-vinyl pyrrolidone aqueous solution with a mass concentration of 0.3-0.8%, 10-20 parts by weight of a 2-acrylamide-2-methylpropanesulfonic acid aqueous solution with a mass concentration of 1-5%, and 15-25 parts by weight of the modified monomer solution are uniformly mixed, 0.001-0.002 parts by weight of a shielding agent and 1-3 parts by weight of a chain transfer agent are added, stirred evenly, and then nitrogen is introduced for deoxygenation to obtain a mixed solution; The temperature of the mixed solution is adjusted to (-2°C)-5°C. Under nitrogen protection, 3-5 parts by weight of an initiator aqueous solution with a mass concentration of 0.1%-0.3% are added dropwise to the mixed solution. After the initiator aqueous solution is added, the mixture is reacted for 4-8 hours. Then, a co-solvent is added and stirred evenly. The mixture is then discharged, granulated and dried to obtain polyacrylamide.

2. The method for preparing a quick-dissolving polyacrylamide for offshore oil displacement according to claim 1, characterized in that: The molecular formula of the glycidyl ester containing a carbon-carbon double bond is CH2=CHCH2(OCH2CH2) n OCH2COOCH2CH(O)CH2, wherein the value of n is in the range of 5-20.

3. A method for preparing an instant polyacrylamide for offshore oil displacement according to claim 2, characterized in that: The value range of n is 8-12.

4. The method for preparing a quick-dissolving polyacrylamide for offshore oil displacement according to claim 1, characterized in that: The bisamino silicone oil is bisaminopropyl polydimethylsiloxane, and the molecular formula is H2N(CH2)3Si(CH3)2O[Si(CH3)2O] m Si(CH3)2(CH2)3NH2, wherein the value of m ranges from 10 to 30.

5. A method for preparing an instant polyacrylamide for offshore oil displacement according to claim 4, characterized in that: The value range of m is 15-20.

6. A method for preparing a quick-dissolving polyacrylamide for offshore oil displacement according to any one of claims 1 to 5, characterized in that: In the modified monomer solution, the glycidyl ester containing carbon-carbon double bonds is 20-28 parts by weight, the bisamino silicone oil is 14-18 parts by weight, and the alcohol solution is 600-800 parts by weight.

7. A method for preparing a quick-dissolving polyacrylamide for offshore oil displacement according to any one of claims 1 to 5, characterized in that: Before adding the initiator solution, the temperature of the mixed solution was (-1°C)-1°C.

8. A method for preparing a quick-dissolving polyacrylamide for offshore oil displacement according to any one of claims 1 to 5, characterized in that: The initiator aqueous solution is added in three times; the amount of the initiator aqueous solution added in the first time is 25-35wt% of the total amount of the initiator aqueous solution, and the dropping speed is 0.05-0.1g / min; the amount of the initiator aqueous solution added in the second time is 40-50wt% of the total amount of the initiator aqueous solution, and the dropping speed is 0.1-0.2g / min; the dropping speed of the initiator aqueous solution in the third time is 0.2-0.5g / min, and the interval between the addition of two adjacent initiator aqueous solutions is 30-45min.

9. A method for preparing a quick-dissolving polyacrylamide for offshore oil displacement according to any one of claims 1 to 5, characterized in that: The cosolvent is selected from one or more of sodium carboxymethyl starch, sodium glycolate starch, polyvinyl pyrrolidone, and sodium carboxymethyl cellulose.

10. A polyacrylamide prepared according to the method for preparing instant polyacrylamide for offshore oil displacement according to any one of claims 1 to 9.

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