CN113025292B - High-strength gel temporary plugging agent for plugging horizontal shaft before workover of thermal recovery horizontal well and preparation method thereof - Google Patents

Abstract

The invention relates to a high-strength gel temporary plugging agent for plugging a horizontal shaft before workover of a thermal recovery horizontal well and a preparation method thereof. The temporary plugging agent is prepared from hot sewage at 80 ℃, primary crosslinking can occur to the gel forming liquid at the temperature lower than 100 ℃, a weak crosslinking gel forming liquid with certain viscosity is formed, and the temporary plugging agent has pumping performance and simultaneously avoids the gel forming liquid from being filtered to the stratum and being diluted when meeting well water. The high-strength gel rubber plug can be quickly crosslinked to form a high-strength gel rubber plug sealed shaft at the temperature higher than 100 ℃, so that the overflow of stratum hot fluid is prevented, the stability is realized for 3-5 days at the temperature of 200 ℃, and the safety of the workover operation of the thermal recovery horizontal well is ensured; after 7 days, the strength is gradually broken, the production can be recovered, and the oil extraction efficiency is not influenced.

Description

A kind of high-strength jelly temporary plugging agent for plugging horizontal wellbore before workover of thermal recovery horizontal well and its preparation method

technical field

The invention relates to the field of oilfield chemistry, in particular to a high-strength jelly temporary plugging agent. The temporary plugging agent is injected into the horizontal section of the wellbore before the workover of the thermal recovery horizontal well, so as to block the overflow of the formation thermal fluid and provide a solution for subsequent non-discharge. Create conditions for liquid operations.

Background technique

In my country, heavy oil with a viscosity greater than 3000mPa·s (formation temperature or 50°C) is mainly developed by steam injection, including steam flooding, steam huff and puff, etc. In recent years, SAGD has achieved good results for shallow extra-heavy oil in the Fengcheng operation area of Xinjiang Oilfield. A large amount of superheated steam is injected into the formation to reduce the viscosity of the heavy oil. However, when the oil well needs to check the pump due to problems such as sand production, scaling, and eccentric wear, measures must be taken to prevent formation hot fluid from gushing out of the well after the high-pressure wellhead is dismantled during operation. These measures include high-density well killing hydraulic wells, well opening and drainage, injection of plugging agents, etc. High-density kill hydraulic wells are relatively mature technology for treating formations with a wellbore temperature of 120°C. Well failed. For wells to be operated that cannot be killed at high temperature, in order to reduce the formation temperature and formation pressure, it is necessary to drain liquid for a long time. Drainage prolongs the operating cycle while reducing formation capacity and reducing oilfield productivity. Injecting a high-temperature temporary plugging agent into the wellbore can temporarily seal the formation within 3 to 5 days, which can ensure the smooth completion of operations and improve production efficiency.

Different from the temporary plugging agent used to prevent the leakage of well flushing fluid into the formation, the plugging agent used to temporarily plug formation fluid to create conditions for subsequent operations generally does not use granular temporary plugging agent, but mainly uses jelly type plugging agent. The plugging agent has high elasticity. For oil and water wells in deep target wells or deep thermal recovery oilfields, due to the high temperature of the formation fluid, the temporary plugging agent for auxiliary operations is required to have a strong temperature resistance within a certain period of time. At present, there are two main types of temporary plugging agents used to plug wellbore fluids before operation. One type is a system composed of relatively high content monomers (mass fraction of monomers is greater than 4%). Under the action of the wellbore and near wellbore, high-strength cross-linked polymers can be formed. Another type of gel formed by polymers under the action of cross-linking agents. The former has high strength, but it is difficult to control the polymerization time when the temperature is higher than 90°C; the latter is easy to control the crosslinking time, but the strength of the formed jelly is lower than that of the first type of system.

There are also many patent documents and reports on plugging agents, for example: CN103160261A discloses the preparation and use method of a downhole intelligent rubber plug, and CN104628957A relates to a high-strength jelly for snubbing operation and its preparation method. CN102191023A discloses a temporary plugging agent for medium-high temperature (80°C-100°C) oil and gas reservoirs. CN104449618A discloses a temperature-resistant, salt-resistant, high-temperature self-crosslinking in-situ polymerized water plugging gel, and CN109280542A discloses a high-temperature resistant gel plugging agent and its preparation method and application. Patent CN110669484A discloses a degradable temporary plugging agent for well workover and its preparation method.

However, in the prior art above, high-strength plugging agents are formed by polymerizing high-amount monomers in formations. The disadvantage of this type of temporary plugging agent is that it polymerizes too quickly at high temperature. When the formation temperature is higher than 150°C, it is difficult to control the polymerization time even if a retarder is added, so that it is impossible to ensure the smooth injection of the gelling liquid into the target layer, so it is suitable for medium and low temperature.

Another kind of temporary plugging agent is constructed by polymer and cross-linking agent, for example: CN104694093A relates to a kind of high-temperature fluid slug glue and its application which can seal off oil and gas; CN106566488A discloses a kind of well killing polymer gel and Its preparation method and application. CN101135237A discloses a preparation method of an underground jelly valve and a construction method thereof. CN107011879A discloses a high-temperature resistant high-strength composite cross-linked jelly sealant and a preparation method thereof. CN106905940A discloses a medium-to-high-density elastic liquid rubber plug, and CN105131921A discloses a preparation method of temperature-resistant and salt-resistant jelly. However, the temperature resistance of the jelly formed by cross-linking the above-mentioned polymers does not exceed 180°C, which is difficult to meet the requirements of sealing 200°C steam in the wellbore.

In addition, CN103232839A reports a jelly blocking agent prepared from tannin extract and lignin as raw materials. This kind of plugging agent has strong temperature resistance, once it is gelled, it is difficult to break through heat and gel breaker, so it is not suitable for use as a temporary plugging agent. Moreover, due to the small molecular weight of tannin extract and alkali lignin, the formed jelly is brittle and lacks elasticity, and basically has no adhesion ability on the surface of the screen pipe, so it is difficult to form an effective sealing layer in the wellbore.

Contents of the invention

In view of the deficiencies of the prior art, especially the lack of temperature resistance of the jelly in the prior art, it is difficult to meet the requirement of blocking steam at 200°C. In the present invention, a multi-component gel solution is injected into the well section below the horizontal well pump to form a high-strength jelly slug with a temperature resistance of 200°C, thereby preventing the steam from overflowing the wellbore and realizing rapid workover. The gelling solution of the present invention contains a temperature-resistant polymer, partially hydrolyzed polyacrylamide, a phenolic crosslinking agent, a chromium crosslinking agent, an oxygen scavenger, an organic acid, and sodium earth.

Technical scheme of the present invention is as follows:

A high-strength jelly temporary plugging agent for plugging a horizontal wellbore before workover of a thermal recovery horizontal well, comprising the following components by mass percentage:

Heat-resistant polymer 0.5%-2.5%, partially hydrolyzed polyacrylamide 0.1%-0.5%, phenolic crosslinking agent 0.2%-0.8%, chromium crosslinking agent 0.1%-0.5%, oxygen scavenger 0.1%-0.5%, Organic acid 0.05%-0.3%, sodium soil 2%-6%, and the balance is water.

According to the present invention, preferably, the high-strength jelly temporary plugging agent for plugging the horizontal wellbore before the workover of the thermal recovery horizontal well comprises the following components by mass percentage:

Heat-resistant polymer 1%-2%, partially hydrolyzed polyacrylamide 0.2%-0.4%, phenolic crosslinking agent 0.3%-0.5%, chromium crosslinking agent 0.2%-0.4%, oxygen scavenger 0.2%-0.4%, Organic acid 0.08%-0.15%, sodium soil 3%-5%, and the balance is water.

According to the present invention, preferably, the high-strength jelly temporary plugging agent for plugging the horizontal wellbore before the workover of the thermal recovery horizontal well comprises the following components by mass percentage:

1.8% heat-resistant polymer, 0.3% partially hydrolyzed polyacrylamide, 0.4% phenolic crosslinking agent, 0.3% chromium crosslinking agent, 0.3% oxygen scavenger, 0.1% organic acid, 4% sodium soil, and the balance is water.

According to the present invention, preferably, the temperature-resistant polymer is selected from acrylamide/2-acrylamide-2-methylpropanesulfonic acid/vinylpyrrolidone (AM-AMPS-NVP) polymer;

Preferably, the relative molecular weight of the temperature-resistant polymer is 3 million to 8 million, more preferably 4 million;

Preferably, when the temperature-resistant polymer is prepared, the molar ratio of acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, and vinylpyrrolidone is 1: (1-2): (1-5);

Preferably, the molar content of vinylpyrrolidone chains in the heat-resistant polymer is 30% to 70%, more preferably 60%.

According to the present invention, preferably, the molecular weight of the partially hydrolyzed polyacrylamide is 8 million to 18 million, more preferably 12 million to 15 million; the degree of hydrolysis is 20% to 30%, more preferably 25% to 30%.

According to the present invention, preferably, the phenolic crosslinking agent is composed of phenolic substances and aldehyde substances;

Preferably, one or both of phenolic substances are selected from phenol, hydroquinone, and resorcinol, more preferably hydroquinone; One or two kinds of tropins, more preferably m-phthalaldehyde;

Preferably, the molar ratio of phenolic substances to aldehyde substances in the phenolic crosslinking agent is 1:(1-1.2), more preferably 1:1.

According to the present invention, preferably, the chromium crosslinking agent is selected from chromium acetate, chromium lactate or chromium citrate, more preferably chromium acetate.

According to the present invention, preferably, the oxygen scavenger is sodium sulfite, sodium bisulfite or thiourea, more preferably thiourea.

According to the present invention, preferably, the organic acid is acetic acid, butyric acid or valeric acid, more preferably acetic acid.

According to the present invention, the effect of each component is as follows:

The acrylamide/2-acrylamide-2-methylpropanesulfonic acid/vinylpyrrolidone polymer used in the present invention is a temperature-resistant polymer, and the amide group in the polymer can be cross-linked with a phenolic cross-linking agent to form a frozen glue. Although the pyrrolidone ring in the polymer does not participate in the crosslinking reaction, it has three important functions in the formed jelly: (1) the pyrrolidone ring can form a coordination bond with the metal to increase the adhesion of the jelly on the metal surface; 2) The pyrrolidone ring has a strong adsorption capacity on the surface of sodium soil, which can greatly increase the strength of the gel; (3) The pyrrolidone ring is a stable hydrophilic group, which can make the gel have better water retention at high temperature ability.

In the present invention, hydroquinone and m-phthalaldehyde are used to crosslink acrylamide/2-acrylamide-2-methylpropanesulfonic acid/vinylpyrrolidone mainly for controlling the speed of crosslinking reaction. In order to improve the strength of the jelly plug, the present invention uses higher mass fraction polymers and crosslinking agents, the higher the content of these components in the gelling solution, the faster the crosslinking reaction speed; Viscosity, the present invention can be configured into a glue solution with hot sewage at 80°C, and this temperature is also conducive to the crosslinking of phenol, aldehyde and amide groups. Considering the above factors comprehensively, in order to control the reaction speed, the present invention selects terephthalaldehyde with stronger steric hindrance effect to replace formaldehyde, paraformaldehyde, urotropine, etc. The cross-linking system composed of hydroquinone and terephthalaldehyde will not react with the amide group in the polymer molecule at 80°C. When the temperature is higher than 100°C, it can quickly cross-link with the amide group to form a gel . This prevents the high-content gelling liquid from forming high-viscosity jelly in the process of transportation and injection, resulting in construction accidents.

Another polymer used in the present invention is partially hydrolyzed polyacrylamide (HPAM) with a degree of hydrolysis of 20% to 30%. Adding low mass fraction of partially hydrolyzed polyacrylamide and chromium acetate into the gelling solution can make the gelling solution quickly form a network structure with a certain viscosity. This design has two functions. One is to prevent the gelling liquid from being diluted by the water in the wellbore during injection into the formation and reduce the strength of the gel plug; the other is that after the gelling liquid forms primary cross-linking, it can have Certain pressure bearing capacity to avoid filtration loss to the formation under liquid column pressure. The polymer can be rapidly cross-linked with chromium acetate.

The purpose of adding the organic acid in the present invention is to keep the gelling solution weakly acidic, prevent the hydroquinone from being oxidized during the configuration and transportation of the gelling solution, and reduce the gelling performance of the hydroquinone.

The oxygen scavenger in the present invention can reduce the oxygen content of the colloid and prevent the oxidative degradation of the polymer.

The sodium soil in the present invention, also known as bentonite, is dispersed in water to form a sheet structure with a thickness of nanometer scale. The lamellar structure itself has a strong hydration ability, and can form hydrogen bonds with the amide groups and pyrrolidone rings of the temperature-resistant polymer, increasing the grid density of the cross-linked system. The above-mentioned effects increase the stability of the jelly and improve the strength of the jelly.

The present invention also provides a preparation method of the high-strength jelly temporary plugging agent for plugging the horizontal wellbore before the workover of the above-mentioned thermal recovery horizontal well, including the following steps:

Add sodium soil to the water under stirring conditions, stir well, add phenolic crosslinking agent, oxygen scavenger, organic acid, stir well, slowly add temperature-resistant polymer and partially hydrolyzed polyacrylamide under stirring conditions, stir well, Finally, add the chromium cross-linking agent, stir evenly, and you get it.

The beneficial effects of the present invention are as follows:

1. The jelly plugging agent of the present invention has a temperature resistance of over 200°C, which can meet the requirement of blocking steam at 200°C.

2. The jelly plugging agent of the present invention has relatively high strength, and the elastic modulus of the jelly after heat treatment at 200° C. for 4 days still reaches above 481 Pa.

3. The jelly plugging agent of the present invention forms jelly at a temperature above 80°C. This is convenient for transportation and storage, and avoids the formation of high-viscosity jelly in the process of transportation and injection of high-content gelling liquid, which causes construction accidents.

4. Due to the cross-linking effect of HPAM and chromium acetate, the colloidal solution configured in the present invention exhibits a weak jelly and will not disperse when it encounters water, so it will not be diluted by the water in the wellbore after it is injected into the wellbore.

5. The jelly plugging agent of the present invention can be prepared from hot sewage at 80°C, saving water costs. At a temperature lower than 100°C, the gelling fluid will undergo primary cross-linking to form a weakly cross-linking gelling fluid with a certain viscosity, which is pumpable and prevents the gelling fluid from leaking into the formation and being diluted by wellbore water. When the temperature is higher than 100°C, it will quickly cross-link to form a high-strength gel plug to seal the wellbore and prevent formation hot fluid from overflowing. It is stable at 200°C for 3 to 5 days to ensure the safety of thermal recovery horizontal well workover operations; after 7 days, the strength gradually breaks. , can resume production without affecting oil recovery efficiency.

detailed description

The present invention will be further described below by specific examples, but not limited thereto.

The raw materials used in the examples are conventional raw materials.

The acrylamide/2-acrylamide-2-methylpropanesulfonic acid/vinylpyrrolidone polymer described in the examples, during preparation, acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, vinylpyrrolidone The molar ratio is 1:(1-2):(1-5); the molar content of the vinylpyrrolidone chain unit in the temperature-resistant polymer is 60%.

Example 1

Take 1000g of deoiled hot sewage at 80°C from the joint station, and add 40g of bentonite while stirring. After stirring at high speed for 4 hours, add 4 g of isophthalaldehyde, 4 g of hydroquinone, 3 g of thiourea, and 3 g of acetic acid, and stir for 10 min. Then, 18 grams of AM-AMPS-NVP copolymer with a relative molecular weight of 4 million and 3 g of HPAM with a molecular weight of 13 million and a degree of hydrolysis of 27% were slowly added under stirring conditions, and stirred for 2 hours. Finally, add 1 g of chromium acetate and stir evenly to obtain a high-strength jelly temporary plugging agent for plugging horizontal wellbores before workover of thermal recovery horizontal wells.

Example 2

Take 1000g of deoiled hot sewage at 80°C from the joint station, and add 30g of bentonite while stirring. After stirring at high speed for 4 hours, add 3 g of terephthalaldehyde, 3 g of phenol, 2 g of sodium sulfite, and 2 g of butyric acid, and stir for 10 min. Then 10 grams of AM-AMPS-NVP copolymer with a relative molecular weight of 3 million and 2 g of HPAM with a molecular weight of 9 million and a degree of hydrolysis of 22% were slowly added under stirring conditions, and stirred for 2 hours. Finally, 2 g of chromium citrate was added and stirred evenly to obtain a high-strength jelly temporary plugging agent for plugging horizontal wellbores before workover of thermal recovery horizontal wells.

Example 3

Take 1000g of deoiled hot sewage at 80°C from the joint station, and add 50g of bentonite while stirring. After stirring at high speed for 4 hours, add 4 g of urotropine, 3 g of resorcinol, 4 g of sodium bisulfite, and 2 g of valeric acid, and stir for 10 min. Then slowly add 20 grams of AM-AMPS-NVP copolymer with a relative molecular weight of 7 million and 4 g of HPAM with a molecular weight of 15 million and a degree of hydrolysis of 30% under stirring conditions, and stir for 2 hours. Finally, add 3 g of chromium lactate and stir evenly to obtain a high-strength jelly temporary plugging agent for plugging horizontal wellbores before workover of thermal recovery horizontal wells.

Comparative example 1

Take 1000g of deoiled hot sewage at 80°C from the joint station, and add 40g of bentonite while stirring. After stirring at high speed for 4 hours, add 4 g of urotropine, 4 g of hydroquinone, 3 g of thiourea, and 3 g of acetic acid, and stir for 10 min. Then, 18 grams of AM-NVP-AMPS copolymer and 3 g of HPAM polymer were slowly added under stirring conditions, and stirred for 2 hours. Finally, 1 g of chromium acetate was added and stirred.

Comparative example 2

Take 1000g of deoiled hot sewage at 80°C from the joint station, and add 40g of bentonite while stirring. After stirring at high speed for 4 hours, add 4 g of isophthalaldehyde, 4 g of hydroquinone, 3 g of thiourea, and 3 g of acetic acid, and stir for 10 min. Then, 18 grams of AM-AMPS copolymer and 3 g of HPAM polymer were slowly added under the condition of stirring, and stirred for 2 hours. Finally, 1 g of chromium acetate was added and stirred.

Comparative example 3

Take 1000g of deoiled hot sewage at 80°C from the joint station, and add 40g of bentonite while stirring. After stirring at high speed for 4 hours, add 4 g of isophthalaldehyde, 4 g of hydroquinone, and 3 g of thiourea, and stir for 10 min. Then, 18 grams of AM-AMPS-NVP copolymer and 3 g of HPAM polymer were slowly added under stirring conditions, and stirred for 2 hours. Finally, 1 g of chromium acetate was added and stirred.

Comparative example 4

Take 1000g of deoiled hot sewage at 80°C from the joint station, and add 40g of silica sol (median particle size: 15nm) while stirring. After stirring at high speed for 4 hours, add 4 g of isophthalaldehyde, 4 g of hydroquinone, 3 g of thiourea, and 3 g of acetic acid, and stir for 10 min. Then, 18 grams of AM-AMPS-NVP copolymer particles and 3 g of HPAM polymer particles were slowly added under stirring conditions, and stirred for 2 hours. Finally, 1 g of chromium acetate was added and stirred for 30 min.

Comparative example 5

Take 1000g of deoiled hot sewage at 80°C from the joint station, and add 40g of bentonite while stirring. After stirring at high speed for 4 hours, add 4 g of isophthalaldehyde, 4 g of hydroquinone, 3 g of thiourea, and 3 g of acetic acid, and stir for 10 min. Then slowly add 18 grams of AM-AMPS-NVP copolymer under the condition of stirring, and stir for 2 hours.

Test example 1

The jelly properties obtained in Test Example 1 and Comparative Examples 1-5 are shown in Table 1.

Table 1 The determination of the jelly properties formed by different components

It can be seen from Table 1 that in Comparative Example 1, urotropine was used instead of isophthalaldehyde. Although the formed jelly had good strength at 200°C for three days, the gelation time was faster at high temperature, and it was difficult to guarantee the blocking agent. Smooth injection into long horizontal well bores. In Comparative Example 2, AM-AMPS copolymer was used instead of AM-NVP-AMPS copolymer, the stability of the formed jelly was significantly reduced, and the strength of the jelly was greatly reduced after heat treatment at 200°C for 2 days. In Comparative Example 3, no acetic acid was added, and the strength and stability of the formed jelly were also significantly reduced. In Comparative Example 4, silica sol was used instead of sodium soil as a stabilizer, and the strength and stability of the formed jelly were also reduced. After 3 days of heat treatment at 200°C, the strength of the jelly could not meet the requirements for use. Comparative Example 5 did not add HPAM and chromium acetate in the colloidal solution. Although the formation strength and stability were similar to those of the examples, the colloidal solution could not form a network structure due to the lack of fast crosslinking of chromium in the colloidal solution. The gelling solution will disperse when it enters the water; and the colloidal solution configured in the embodiment, due to the cross-linking effect of HPAM and chromium acetate, the colloidal solution shows a weak jelly, and will not disperse when it encounters water, so it will not disperse after being injected into the wellbore. Will be diluted by wellbore water.

Claims (9)

1. a high-strength jelly temporary plugging agent for plugging horizontal wellbore before workover of thermal recovery horizontal well, it is characterized in that, this temporary plugging agent is made up of the component of following mass percentage: Temperature-resistant polymer 0.5%-2.5%, partially hydrolyzed polyacrylamide 0.1%-0.5%, phenolic crosslinking agent 0.2%-0.8%, chromium crosslinking agent 0.1%-0.5%, oxygen scavenger 0.1%-0.5%, Organic acid 0.05%-0.3%, sodium soil 2%-6%, the balance is water; The temperature-resistant polymer is selected from acrylamide/2-acrylamide-2-methylpropanesulfonic acid/vinylpyrrolidone (AM-AMPS-NVP) polymer; The molecular weight of the partially hydrolyzed polyacrylamide is 8 million to 18 million, and the degree of hydrolysis is 20% to 30%. 2. The high-strength jelly temporary plugging agent for plugging the horizontal wellbore before the workover of the thermal recovery horizontal well according to claim 1, characterized in that, the high-strength jelly used for plugging the horizontal wellbore before the workover of the thermal recovery horizontal well is The jelly temporary plugging agent consists of the following components in mass percentage: Temperature-resistant polymer 1%-2%, partially hydrolyzed polyacrylamide 0.2%-0.4%, phenolic crosslinking agent 0.3%-0.5%, chromium crosslinking agent 0.2%-0.4%, oxygen scavenger 0.2%-0.4%, Organic acid 0.08%-0.15%, sodium soil 3%-5%, and the balance is water. 3. The high-strength jelly temporary plugging agent for plugging the horizontal wellbore before the workover of the thermal recovery horizontal well according to claim 1, characterized in that the relative molecular mass of the temperature-resistant polymer is 3 million to 8 million. 4. the high-strength jelly temporary plugging agent for plugging the horizontal wellbore before the workover of the thermal recovery horizontal well according to claim 3 is characterized in that, when the temperature-resistant polymer is prepared, acrylamide, 2-acrylamide-2- The molar ratio of methylpropanesulfonic acid and vinylpyrrolidone is 1: (1-2): (1-5); the molar content of vinylpyrrolidone chains in the temperature-resistant polymer is 30% to 70%. 5. The high-strength jelly temporary plugging agent for plugging the horizontal wellbore before the workover of the thermal recovery horizontal well according to claim 1, characterized in that, the phenolic cross-linking agent is composed of phenolic substances and aldehydes; One or two of phenol, hydroquinone, and resorcinol are selected for phenolic substances, and one or two of isophthalaldehyde, terephthalaldehyde, and urotropine are selected for aldehyde crosslinking agents; The molar ratio of phenols and aldehydes in the phenolic crosslinking agent is 1: (1-1.2). 6. The high-strength jelly temporary plugging agent for plugging horizontal wellbore before workover of thermal recovery horizontal well according to claim 1, characterized in that, the chromium crosslinking agent is selected from chromium acetate, chromium lactate or chromium citrate . 7. The high-strength jelly temporary plugging agent for plugging the horizontal wellbore before the workover of the thermal recovery horizontal well according to claim 1, wherein the oxygen scavenger is sodium sulfite, sodium bisulfite or thiourea. 8. The high-strength jelly temporary plugging agent for plugging horizontal wellbore before workover of thermal recovery horizontal well according to claim 1, characterized in that, the organic acid is acetic acid, butyric acid or valeric acid. 9. the preparation method of the high-strength jelly temporary plugging agent for plugging the horizontal shaft before the thermal recovery horizontal well workover described in claim 1, comprises the steps as follows: Add sodium soil to the water under stirring conditions, stir well, add phenolic crosslinking agent, oxygen scavenger, organic acid, stir well, slowly add temperature-resistant polymer and partially hydrolyzed polyacrylamide under stirring conditions, stir well, Finally, add the chromium cross-linking agent, stir evenly, and you get it.