Liquid-based temperature-controlled viscosity-changing diverting agent and its preparation method

Abstract

This invention discloses a base liquid-type temperature-controlled viscosity-changing diverting agent and its preparation method, belonging to the field of oil and gas extraction technology. The temperature-controlled viscosity-changing diverting agent comprises the following components by mass fraction: 25%–30% cationic monomer, 1%–2.5% acrylamide, 1%–2% vinylpyrrolidone, 0.08%–0.1% initiator, 1%–2% chain transfer inhibitor, 20%–25% white oil, 2%–4% emulsifier, and the remainder being water; wherein the cationic monomer is one or more of trimethylaminopropylmethacrylamide chloride and acryloyloxyethyltrimethylammonium chloride. The temperature-controlled viscosity-changing diverting agent provided by this invention, through the synergistic compounding of the above components, can be used to formulate diverting acids for acidizing, effectively solving the problems of limited temperature resistance and adaptability of existing conventional diverting acid systems, and the low dispensing efficiency of conventional temperature-controlled viscosity-changing thickeners. In acidizing operations, it effectively improves the viscosity-changing diverting capability of the acid system and enhances the effectiveness of the measures.

Description

Technical Field

[0001] This invention relates to the field of oil and gas extraction technology, specifically to a base liquid-type temperature-controlled viscosity-changing diverting agent and its preparation method. Background Technology

[0002] With the deepening development of carbonate reservoirs both domestically and internationally, the demand for acidizing and acid fracturing operations is increasing. In China, acid fracturing is mainly used to stimulate high-temperature, deep, and low-permeability carbonate reservoirs to achieve high oil and gas well production. Internationally, such as in the Missan and Majnoon oil fields in Iraq, acidizing operations are mainly carried out on high-permeability, porous carbonate reservoirs to improve oil well production.

[0003] For fractured carbonate reservoirs, increasing the stimulation volume to achieve lateral and vertical fracture diversion is crucial for enhancing the stimulation effect. However, conventional diversion acid systems have relatively low temperature resistance and shear resistance, resulting in poor temporary diversion effects in deep, high-temperature, and high-stress reservoirs. Temperature-controlled variable viscosity acid systems are often used as the main acid or for temporary diversion to improve acid fracturing. However, conventional variable viscosity acid systems require long preparation times, and insufficient dissolution of the thickener can easily lead to fisheyes, affecting fluid performance and hindering continuous mixing during large-scale acid fracturing operations. For carbonate reservoirs with high permeability, significant variations, high porosity, and relatively high temperatures, coupled with long production well sections, numerous perforated sections, and large inter-layer spans, temporary diversion is necessary during acid enhancement operations to achieve stratified acid enhancement without changing the tubing string, ensuring that each section achieves acid enhancement production.

[0004] Currently, existing technologies have at least the following problems: conventional diverting acid systems have poor temperature resistance, reduced temporary plugging performance in high-permeability reservoirs, low pumping capacity and low acid penetration ability when pumped through coiled tubing; conventional temperature-controlled viscosity-changing acid systems use thickeners for liquid preparation, which is complex and cannot achieve continuous mixing. Summary of the Invention

[0005] Based on this, the present invention proposes a base liquid-type temperature-controlled viscosity-changing diverting agent and its preparation method to solve the problems of temperature difference resistance of existing diverting acids and the complexity of conventional temperature-controlled viscosity-changing acid preparation, so as to achieve the purpose of high-quality and high-efficiency acidizing (pressurization) of oil and water wells.

[0006] According to a first aspect of the present invention, a base liquid-type temperature-controlled viscosity-changing agent is provided, comprising the following components by mass fraction:

[0007] The composition consists of 25%–30% cationic monomer, 1%–2.5% acrylamide, 1%–2% vinylpyrrolidone, 0.08%–0.1% initiator, 1%–2% chain transfer inhibitor, 20%–25% white oil, 2%–4% emulsifier, and the remainder is water.

[0008] The cationic monomer is one or more of trimethylaminopropylmethacrylamide chloride and acryloyloxyethyltrimethylammonium chloride.

[0009] According to an embodiment of the present invention, the initiator is a mixture of potassium persulfate, sodium bisulfite and AP-10 in a mass percentage ratio of 1:1:1.

[0010] According to an embodiment of the present invention, the chain transfer inhibitor is urea.

[0011] According to an embodiment of the present invention, the emulsifier is at least one of SP-60 emulsifier and SP-80 emulsifier.

[0012] According to a second aspect of the present invention, a method for preparing a base liquid-type temperature-controlled viscosity-shifting agent is provided, wherein the optimized mass spectrometry parameters of the standard sample are verified by performing multiple reaction detection quantitative analysis on the standard sample, comprising:

[0013] Acrylamide, vinylpyrrolidone, cationic monomer, and chain transfer inhibitor were dissolved in water to obtain an aqueous reactant.

[0014] The emulsifier is dissolved in white oil to obtain the oil phase reactant;

[0015] The oil phase reactants are recycled, and the aqueous phase reactants are added under nitrogen purging conditions, along with an initiator, and emulsified to obtain an emulsion product;

[0016] The emulsion product is heated to react, and after the reaction, it is cooled to obtain the base liquid-type temperature-controlled viscosity-changing agent.

[0017] According to an embodiment of the present invention, the oil phase reactant is recycled, and the aqueous phase reactant is added under nitrogen purging conditions, along with an initiator, to emulsify and obtain an emulsion product, comprising:

[0018] Potassium persulfate initiator solution was added to the aqueous phase reactant tank, and the oil phase reactant was circulated. The aqueous phase reactant was added dropwise under nitrogen purging, with the addition proceeding in a fast-then-slow manner. When half of the aqueous phase reactant had been added, sodium bisulfite and AP-10 initiator solution were added dropwise in sequence. After the addition was completed, the mixture was circulated and emulsified for 1 hour to obtain the emulsion product.

[0019] According to an embodiment of the present invention, the step of heating the emulsion product to react, and then cooling it to obtain the base liquid-type temperature-controlled viscosity-shifting agent includes:

[0020] After subjecting the emulsified product to a first-step low-temperature initiated polymerization and / or a second-step low-temperature initiated polymerization, cooling is performed to obtain the base liquid-type temperature-controlled viscosity-shifting agent.

[0021] According to an embodiment of the present invention, the first step of low-temperature initiation polymerization includes: placing the emulsion product at a constant temperature of 30°C for 1 hour while continuously passing nitrogen.

[0022] According to an embodiment of the present invention, the second step of heating-initiated polymerization includes: based on the first step of low-temperature initiated polymerization, allowing the product to react fully at 80°C for 3 hours, and then cooling down to obtain the base liquid-type temperature-controlled viscosity-shifting agent.

[0023] As can be seen from the above technical solutions, the liquid-based temperature-controlled viscosity-changing agent and its preparation method provided by the present invention have the following beneficial effects:

[0024] The present invention provides a base liquid-type temperature-controlled viscosity-changing agent. Through the synergistic compounding of the above components, the prepared base liquid-type temperature-controlled viscosity-changing agent can be used to formulate acid-changing acids for acidification. This acid can change viscosity and change direction within a temperature range of 90℃-120℃, with a peak gel viscosity of up to 260 mPa·s. It can effectively solve the problems of limited temperature resistance and adaptability of existing conventional acid-changing systems, and the problem of low dispensing efficiency of conventional temperature-controlled viscosity-changing thickeners. In acidification (pressure) operations, it effectively improves the viscosity-changing and direction-changing ability of the acid system and improves the effectiveness of the measures. Attached Figure Description

[0025] Figure 1 Viscosity measurements of the system at different temperatures in embodiments of the present invention;

[0026] Figure 2 This invention provides a comparison of the slow-release properties of temperature-controlled viscosity-shifting acid and blank acid in an embodiment of the present invention.

[0027] Figure 3 The rheological curve of the temperature-controlled viscosity-changing acid in an embodiment of the present invention is shown below.

[0028] Figure 4 This invention illustrates the effect of a desiccant on the viscosity of temperature-controlled viscous acids in an embodiment of the invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0030] According to a first aspect of the present invention, a base liquid-type temperature-controlled viscosity-changing agent is provided, comprising the following components by mass fraction:

[0031] The composition consists of 25%–30% cationic monomer, 1%–2.5% acrylamide, 1%–2% vinylpyrrolidone, 0.08%–0.1% initiator, 1%–2% chain transfer inhibitor, 20%–25% white oil, 2%–4% emulsifier, and the remainder is water.

[0032] The cationic monomer is one or more of trimethylaminopropylmethacrylamide chloride and acryloyloxyethyltrimethylammonium chloride.

[0033] According to an embodiment of the present invention, the initiator is a mixture of potassium persulfate, sodium bisulfite and AP-10 in a mass percentage ratio of 1:1:1.

[0034] According to an embodiment of the present invention, the chain transfer inhibitor is urea.

[0035] According to an embodiment of the present invention, the emulsifier is at least one of SP-60 emulsifier and SP-80 emulsifier.

[0036] According to a second aspect of the present invention, a method for preparing a base liquid-type temperature-controlled viscosity-shifting agent is provided, wherein the optimized mass spectrometry parameters of the standard sample are verified by performing multiple reaction detection quantitative analysis on the standard sample, comprising:

[0037] Acrylamide, vinylpyrrolidone, cationic monomer, and chain transfer inhibitor were dissolved in water to obtain an aqueous reactant.

[0038] The emulsifier is dissolved in white oil to obtain the oil phase reactant;

[0039] The oil phase reactants are recycled, and the aqueous phase reactants are added under nitrogen purging conditions, along with an initiator, and emulsified to obtain an emulsion product;

[0040] The emulsion product is heated to react, and after the reaction, it is cooled to obtain the base liquid-type temperature-controlled viscosity-changing agent.

[0041] According to an embodiment of the present invention, the oil phase reactant is recycled, and the aqueous phase reactant is added under nitrogen purging conditions, along with an initiator, to emulsify and obtain an emulsion product, comprising:

[0042] Potassium persulfate initiator solution was added to the aqueous phase reactant tank, and the oil phase reactant was circulated. The aqueous phase reactant was added dropwise under nitrogen purging, with the addition proceeding in a fast-then-slow manner. When half of the aqueous phase reactant had been added, sodium bisulfite and AP-10 initiator solution were added dropwise in sequence. After the addition was completed, the mixture was circulated and emulsified for 1 hour to obtain the emulsion product.

[0043] According to an embodiment of the present invention, the step of heating the emulsion product to react, and then cooling it to obtain the base liquid-type temperature-controlled viscosity-shifting agent includes:

[0044] After subjecting the emulsified product to a first-step low-temperature initiated polymerization and / or a second-step low-temperature initiated polymerization, cooling is performed to obtain the base liquid-type temperature-controlled viscosity-shifting agent.

[0045] According to an embodiment of the present invention, the first step of low-temperature initiation polymerization includes: placing the emulsion product at a constant temperature of 30°C for 1 hour while continuously passing nitrogen.

[0046] According to an embodiment of the present invention, the second step of heating-initiated polymerization includes: based on the first step of low-temperature initiated polymerization, allowing the product to react fully at 80°C for 3 hours, and then cooling down to obtain the base liquid-type temperature-controlled viscosity-shifting agent.

[0047] The technical solution of the present invention will be described in detail below through preferred embodiments. It should be noted that the specific embodiments in the following text are for illustrative purposes only and are not intended to limit the present invention.

[0048] Example 1

[0049] This embodiment provides a base liquid-type temperature-controlled viscosity-changing agent, which is prepared by the following method:

[0050] (1) Preparation of aqueous reactants: Dissolve 6g acrylamide, 6g vinylpyrrolidone, 90g acryloyloxyethyltrimethylammonium chloride and 6g urea in 102g distilled water to obtain aqueous reactants.

[0051] (2) Preparation of initiator solution: Dissolve 0.08g potassium persulfate in 10g distilled water, and dissolve 0.08g sodium bisulfite and 0.08g AP-10 in 10g distilled water to obtain initiator solution.

[0052] (3) Preparation of oil phase reactants: Mix 60g of white oil and 9g of SP80 emulsifier evenly to obtain oil phase reactants.

[0053] (4) Emulsification: Add potassium persulfate initiator solution to the aqueous phase reactant tank, circulate the oil phase reactant, and add the aqueous phase reactant dropwise under nitrogen purging. The dropwise addition should be fast at first and then slow. When half of the aqueous phase reactant has been added, add sodium bisulfite and AP-10 initiator solution in sequence. After the addition is complete, circulate and emulsify for another 1 hour.

[0054] (4) First step: Low-temperature initiation polymerization: After emulsification, the emulsion product is kept at 30°C for 1 hour. During this low-temperature initiation polymerization stage, nitrogen is continuously purged.

[0055] (5) Second step of heating to initiate polymerization: Based on the low temperature initiation polymerization, the second step of heating is started to allow the product to react fully at 80°C for 3 hours, and then the temperature is lowered to obtain the base liquid type temperature-controlled viscosity-shifting agent.

[0056] Example 2

[0057] This embodiment provides a base liquid-type temperature-controlled viscosity-changing agent, which is prepared by the following method:

[0058] (1) Preparation of aqueous reactants: Dissolve 7.5g acrylamide, 4.5g vinylpyrrolidone, 90g trimethylaminopropylmethacrylamide chloride and 6g urea in 102g distilled water to obtain aqueous reactants.

[0059] (2) Preparation of initiator solution: Dissolve 0.08g potassium persulfate in 10g distilled water, and dissolve 0.08g sodium bisulfite and 0.08g AP-10 in 10g distilled water to obtain initiator solution.

[0060] (3) Preparation of oil phase reactants: Mix 60g of white oil and 9g of SP80 emulsifier evenly to obtain oil phase reactants.

[0061] (4) Emulsification: Add potassium persulfate initiator solution to the aqueous phase reactant tank, circulate the oil phase reactant, and add the aqueous phase reactant dropwise under nitrogen purging. The dropwise addition should be fast at first and then slow. When half of the aqueous phase reactant has been added, add sodium bisulfite and AP-10 initiator solution in sequence. After the addition is complete, circulate and emulsify for another 1 hour.

[0062] (4) First step: Low-temperature initiation polymerization: After emulsification, the emulsion product is kept at 40°C for 1 hour. During this low-temperature initiation polymerization stage, nitrogen is continuously purged.

[0063] (5) Second step of heating to initiate polymerization: Based on the low temperature initiation polymerization, the second step of heating is started to allow the product to react fully at 85°C for 3 hours, and then the temperature is lowered to obtain the base liquid type temperature-controlled viscosity-shifting agent.

[0064] Example 3

[0065] This embodiment provides a base liquid-type temperature-controlled viscosity-changing agent, which is prepared by the following method:

[0066] (1) Preparation of aqueous reactants: Dissolve 7.5g acrylamide, 6g vinylpyrrolidone, 35g acryloyloxyethyltrimethylammonium chloride, 40g trimethylaminopropylmethacrylamide chloride and 4.5g urea in 106g distilled water to obtain aqueous reactants.

[0067] (2) Preparation of initiator solution: Dissolve 0.08g potassium persulfate in 10g distilled water, and dissolve 0.08g sodium bisulfite and 0.08g AP-10 in 10g distilled water to obtain initiator solution.

[0068] (3) Preparation of oil phase reactants: Mix 75g white oil, 3g SP80 and 3g SP60 emulsifier evenly to obtain oil phase reactants.

[0069] (4) Emulsification: Add potassium persulfate initiator solution to the aqueous phase reactant tank, circulate the oil phase reactant, and add the aqueous phase reactant dropwise under nitrogen purging. The dropwise addition should be fast at first and then slow. When half of the aqueous phase reactant has been added, add sodium bisulfite and AP-10 initiator solution in sequence. After the addition is complete, circulate and emulsify for another 1 hour.

[0070] (4) First step: Low-temperature initiation polymerization: After emulsification, the emulsion product is kept at 40°C for 1 hour. During this low-temperature initiation polymerization stage, nitrogen is continuously purged.

[0071] (5) Second step of heating to initiate polymerization: Based on the low temperature initiation polymerization, the second step of heating is started to allow the product to react fully at 80°C for 3 hours, and then the temperature is lowered to obtain the base liquid type temperature-controlled viscosity-shifting agent.

[0072] Example 4

[0073] This embodiment provides a base liquid-type temperature-controlled viscosity-changing agent, which is prepared by the following method:

[0074] (1) Preparation of aqueous reactants: Dissolve 7.5g acrylamide, 6g vinylpyrrolidone, 45g acryloyloxyethyltrimethylammonium chloride, 45g trimethylaminopropylmethacrylamide chloride, and 6g urea in 104g distilled water to obtain aqueous reactants.

[0075] (2) Preparation of initiator solution: Dissolve 0.08g potassium persulfate in 10g distilled water, and dissolve 0.08g sodium bisulfite and 0.08g AP-10 in 10g distilled water to obtain initiator solution.

[0076] (3) Preparation of oil phase reactants: Mix 60g of white oil and 6g of SP80 emulsifier evenly to obtain oil phase reactants.

[0077] (4) Emulsification: Add potassium persulfate initiator solution to the aqueous phase reactant tank, circulate the oil phase reactant, and add the aqueous phase reactant dropwise under nitrogen purging. The dropwise addition should be fast at first and then slow. When half of the aqueous phase reactant has been added, add sodium bisulfite and AP-10 initiator solution in sequence. After the addition is complete, circulate and emulsify for another 1 hour.

[0078] (5) First step: Low-temperature initiation polymerization: After emulsification, the emulsion product is kept at 45°C for 1.5 hours. During this low-temperature initiation polymerization stage, nitrogen is continuously purged.

[0079] (6) Second step of heating to initiate polymerization: Based on the low temperature initiation polymerization, the second step of heating is started to allow the product to react fully at 85°C for 4 hours, and then the temperature is lowered to obtain the base liquid type temperature-controlled viscosity-shifting agent.

[0080] Experimental Example

[0081] This application example utilizes the base liquid-type temperature-controlled viscosity-changing diverting agent provided in Examples 1-4 to formulate an acid-changing acid system according to the following diverting acid system formulation, and evaluates the viscosity, retardation properties, rheological properties, and debonding properties of the diverting acid system at different temperatures.

[0082] Formula for acidification diverting acid system: 20% hydrochloric acid + 1% temperature-controlled viscosity diverting agent + 0.6% temperature-controlled crosslinking agent BH-JL + 1% corrosion inhibitor BH-HS + 1% drainage aid BH-ZP.

[0083] (1) Viscosity evaluation

[0084] Viscosities were measured at temperatures ranging from room temperature to 180°C. The experimental results are shown in Table 1 and 2. Figure 1 As shown. The diverting acid prepared by the temperature-controlled viscosity-changing diverting agent provided by the present invention has low viscosity at lower temperatures, which is beneficial for acid pumping; when the temperature reaches the reservoir temperature (90℃-120℃), the viscosity of the diverting acid reaches its peak, which is beneficial for achieving uniform acid distribution; under continuous high temperature conditions, the viscosity of the acid decreases, which is beneficial for acid backflow.

[0085] Table 1. Viscosity determination of the system at different temperatures

[0086]

[0087] (2) Evaluation of slowing performance

[0088] Marble was added to the prepared diluent system, with the amount of marble being 2.5 times the mass of the 20% acid solution. An equal volume of 20% hydrochloric acid was used as a blank acid for comparison. The slowing effect of the temperature-controlled viscous diluent was determined by the weight loss rate of the marble at 90℃. Relevant phenomena observed during the experiment are shown in Table 2. The weight loss rate of the marble is shown in... Figure 2 .

[0089] Table 2. Experimental phenomena during the temperature-controlled viscosity-to-acid reaction process.

[0090]

[0091]

[0092] As can be seen from Table 2, TCA underwent cross-linking to form a gel during the acid-rock reaction; then, the gel ruptured after a certain period of time during the acid-rock reaction; when the pH of the residual acid was 3, the acid-rock reaction was considered to be complete because the H+ concentration in the acid solution was very low.

[0093] from Figure 2 It can be seen that the temperature-controlled viscosity-shifting acid has a significantly slower reaction rate compared to 20% hydrochloric acid. At 90℃, 20% hydrochloric acid is completely consumed within 30 minutes, while the temperature-controlled viscosity-shifting acid is completely consumed after 120 minutes.

[0094] Combination Figure 2 Table 2 also shows that within 5 minutes, because the temperature-controlled viscosity-changing acid had not yet fully formed a gel, the acid viscosity was not high, resulting in a large weight loss rate for the marble and a rapid acid-rock reaction rate. In the subsequent 5-60 minutes, because the temperature-controlled viscosity-changing acid had formed a gel, the viscosity was very high, and H... + The diffusion rate to the marble surface slows down, reducing the acid-rock reaction rate and thus decreasing the rate of marble dissolution. During this period, the temperature-controlled viscosity-shifting acid exhibits excellent retarding properties and also undergoes a temporary blocking effect. After 60 minutes, although the gel begins to break down and hydrate, causing the temperature-controlled viscosity-shifting acid system to decrease and the acid-rock reaction rate to accelerate somewhat, the retarding properties of the temperature-controlled viscosity-shifting acid system remain high. This is mainly because the gel formed by polymer crosslinking degrades under prolonged high temperatures (above 90°C), leading to gel breakage. When the acid-rock reaction time reaches 120 minutes, the pH of the residual acid is measured to be 3, at which point H... + The concentration is very low, indicating that the acid-rock reaction is almost complete.

[0095] (iv) Rheological property evaluation

[0096] For temperature-controlled viscosity-shifting acids, the most important property is the effect of temperature on the entire system. Using a HAAK MARS60 rheometer with an acid-resistant coaxial cylindrical testing module and an acid-resistant 38mm rotor, a constant shear rate of 170s was applied. -1 The apparent viscosity change trend of the temperature-controlled viscosity-shifting acid system at 90℃ was tested. The heating period was 30 min, and the isothermal period was 60 min.

[0097] from Figure 3 It can be seen that the viscosity continuously increases during the heating phase, and the higher the temperature, the greater the rate of viscosity increase. When the temperature reaches 90℃, the viscosity increases to 250 mPa·s, and then decreases to around 100 mPa·s. During the heating stage, the temperature-controlled crosslinking agent and the temperature-controlled viscosity-shifting acid main agent undergo a crosslinking reaction. The crosslinking reaction accelerates with increasing temperature, which further accelerates the viscosity increase rate.

[0098] (V) Evaluation of Destructive Performance

[0099] In the high-temperature and high-pressure environment of the formation, temperature-controlled viscosity-changing acid must not only ensure its viscosity-changing ability but also guarantee that its viscosity can rapidly decrease after construction, thus allowing it to exit the oil and gas flow channels. The viscosity change trend of temperature-controlled viscosity-changing acid under high-temperature conditions was observed by adding an external breaker.

[0100] Adding 0.08% wt of a breaker to a temperature-controlled viscous acid, and using a temperature-controlled viscous acid without the breaker as a control group, the viscosity change curves of the samples at 90℃ over 3 hours were examined. The results are as follows:

[0101] Depend on Figure 4 It can be seen that, with the addition of a breaker, the apparent viscosity of the temperature-controlled viscosity-changing acid begins to decrease sharply after heating for 2 hours and eventually reaches 3 mPa·s. Without the addition of a breaker, the apparent viscosity of the temperature-controlled viscosity-changing acid can also decrease to about 5 mPa·s after heating for 2 hours. The breaker solution does not contain any visible precipitates.

[0102] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A base liquid-type temperature-controlled viscosity-changing diverting agent, characterized in that, According to mass fraction, it includes the following components: The composition consists of 25%–30% cationic monomer, 1%–2.5% acrylamide, 1%–2% vinylpyrrolidone, 0.08%–0.1% initiator, 1%–2% chain transfer inhibitor, 20%–25% white oil, 2%–4% emulsifier, and the remainder is water. The cationic monomer is one or more of trimethylaminopropylmethacrylamide chloride and acryloyloxyethyltrimethylammonium chloride.

2. The base liquid type temperature-controlled viscosity-changing diverting agent according to claim 1, characterized in that, The initiator is a mixture of potassium persulfate, sodium bisulfite, and AP-10 in a mass percentage ratio of 1:1:

1.

3. The base liquid type temperature-controlled viscosity-changing diverting agent according to claim 1, characterized in that, The chain transfer inhibitor is urea.

4. The base liquid type temperature-controlled viscosity-changing diverting agent according to claim 1, characterized in that, The emulsifier is at least one of SP-60 emulsifier and SP-80 emulsifier.

5. A method for preparing a base liquid-type temperature-controlled viscosity-changing agent according to any one of claims 1-4, characterized in that, The step of verifying the optimized mass spectrometry parameters of the standard sample by performing multiple reaction detection quantitative analysis on the standard sample includes: Acrylamide, vinylpyrrolidone, cationic monomer, and chain transfer inhibitor were dissolved in water to obtain an aqueous reactant. The emulsifier is dissolved in white oil to obtain the oil phase reactant; The oil phase reactants are recycled, and the aqueous phase reactants are added under nitrogen purging conditions, along with an initiator, and emulsified to obtain an emulsion product; The emulsion product is heated to react, and after the reaction, it is cooled to obtain the base liquid-type temperature-controlled viscosity-changing agent.

6. The preparation method according to claim 5, characterized in that, The oil phase reactants are recycled, and the aqueous phase reactants are added under nitrogen purging conditions, along with an initiator, to emulsify and obtain an emulsion product comprising: Potassium persulfate initiator solution was added to the aqueous phase reactant tank, and the oil phase reactant was circulated. The aqueous phase reactant was added dropwise under nitrogen purging, with the addition proceeding in a fast-then-slow manner. When half of the aqueous phase reactant had been added, sodium bisulfite and AP-10 initiator solution were added dropwise in sequence. After the addition was completed, the mixture was circulated and emulsified for 1 hour to obtain the emulsion product.

7. The preparation method according to claim 5, characterized in that, The step of heating the emulsion product to react, and then cooling it to obtain the base liquid-type temperature-controlled viscosity-shifting agent includes: After subjecting the emulsified product to a first-step low-temperature initiated polymerization and / or a second-step low-temperature initiated polymerization, cooling is performed to obtain the base liquid-type temperature-controlled viscosity-shifting agent.

8. The preparation method according to claim 7, characterized in that, The first step of low-temperature initiation polymerization includes: placing the emulsion product at a constant temperature of 30°C for 1 hour while continuously purging with nitrogen.

9. The preparation method according to claim 7, characterized in that, The second step of heating-initiated polymerization includes: based on the first step of low-temperature initiated polymerization, allowing the product to react fully at 80°C for 3 hours, and then cooling down to obtain the base liquid-type temperature-controlled viscosity-shifting agent.

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