Temperature-resistant amphiphilic polymer emulsion film-forming protective agent as well as preparation method and application thereof

Abstract

The invention discloses a temperature-resistant amphiphilic polymer emulsion film-forming protective agent as well as a preparation method and application thereof. The temperature-resistant amphiphilic polymer emulsion film-forming protective agent comprises a first functional monomer, a second functional monomer, a third functional monomer and a fourth functional monomer. The temperature-resistant amphiphilic polymer emulsion film-forming protective agent disclosed by the invention has excellent high-temperature resistance and excellent inhibitive ability, and can effectively block multi-scale pores of a high-temperature reservoir section, inhibit hydration expansion of shale and improve the reservoir protection performance of water-based drilling fluid.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical additives for drilling, in particular to a temperature-resistant amphiphilic polymer emulsion film-forming protective agent, a preparation method and application thereof. Background Art

[0002] In terms of oil and gas resources, the shale formations in some areas have high clay content, making them prone to shrinkage and collapse after hydration and expansion. The Paleogene strata are highly compacted and subject to high tectonic stress, making wellbore blockage prone. The lower pre-Paleogene strata are igneous rocks characterized by deep burial depth, dense rock, high temperature, and low porosity and permeability, requiring high reservoir protection. Drilling fluids contacting the reservoirs cause varying degrees of reservoir damage (such as insufficient shielding and incomplete deblocking), and are affected by the sequence of fluid entry and the spatiotemporal evolution of reservoir properties throughout the drilling and production phases. Furthermore, the high bottomhole temperatures and pressures in this area exacerbate existing problems such as wellbore instability (shale hydration and expansion), lost circulation (improper pressure control), stuck pipe (slow drilling speed), and reservoir damage (difficult flowback) under these high-temperature and high-pressure conditions, severely hindering the efficient exploration and development of oil and gas reservoirs.

[0003] Currently, common reservoir protection agents used in offshore oil and gas drilling include acid-soluble and oil-soluble solid particles and chemical additives such as oil film agents and water-based film-forming agents. Solid particles can be optimized using particle size theory to form a temporary barrier zone with extremely low permeability near the wellbore wall, preventing subsequent solid and liquid intrusion and thus preventing reservoir damage. During completion, perforation, dissolution, and flowback processes are used to clear the blockage and restore oil and gas flow. However, reservoir pore size and fractures cannot be predicted in advance, making solid particle temporary plugging ineffective when drilling into heterogeneous reservoirs. More importantly, in low-permeability, high-pressure reservoirs, solid particles are unable to prevent liquid intrusion. Oil film agents and chemical film-forming agents can address liquid damage by forming a chemical film on the wellbore wall. However, challenges remain, such as incomplete film formation theory and low film strength. Films are particularly susceptible to damage in high-temperature reservoirs, leading to an urgent need to improve their high-temperature resistance (≥180°C). In general, the technical problems of drilling fluids encountered in current marine drilling work, such as high temperature, poor sealing and clay expansion, cannot be effectively and thoroughly solved.

[0004] Therefore, there is an urgent need for a high-temperature reservoir protective agent that can both seal multi-scale pores and effectively inhibit shale hydration expansion. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a temperature-resistant amphiphilic polymer emulsion film-forming protective agent that can block multi-scale pores and effectively inhibit hydration expansion of shale, as well as a preparation method and application thereof.

[0006] The technical solution adopted by the present invention to solve the technical problem is: providing a heat-resistant amphiphilic polymer emulsion film-forming protective agent, wherein the heat-resistant amphiphilic polymer emulsion film-forming protective agent is a cationic nanopolymer emulsion, and the raw materials include a first functional monomer, a second functional monomer, a third functional monomer and a fourth functional monomer, and the molecular structures of the first functional monomer, the second functional monomer, the third functional monomer and the fourth functional monomer are respectively shown in the following formulas (1) to (4):

[0007]

[0008]

[0009] Wherein, R1 is H or methyl, R2 is selected from any one of ethyl ester, butyl ester, and isooctyl ester, R3 is para-phenylene or 2-amido-2-methylpropyl, R4 is H or methyl, the structure formed by R5 and the alkenyl group is selected from any one of vinyl, acrylamidopropyl, and acryloxyethyl, and X- is an anion selected from any one of chloride, bromide, iodide, and sulfonate anions.

[0010] In some embodiments, the polymer molecular structure of the cationic nanopolymer emulsion is shown in the following formula (V):

[0011]

[0012] Among them, x:y:z:p is 18-29:43-74:1:1.

[0013] In some embodiments, the mass ratio of the first functional monomer, the second functional monomer, the third functional monomer, and the fourth functional monomer is 15-25:30-50:1-2:1-2.

[0014] The present invention also provides a method for preparing a temperature-resistant amphiphilic polymer emulsion film-forming protective agent, comprising the following steps:

[0015] S1, mixing the first functional monomer, the second functional monomer and the third functional monomer to form a first mixed solution;

[0016] S2, adjusting the pH of the first mixed solution to 8-9, and stirring to form a stable emulsion;

[0017] S3, heating the stable emulsion to 50° C. to 60° C., adding an initiator and maintaining the temperature for 10 min to 30 min;

[0018] S4. The stable emulsion is heated to 70° C. to 75° C., an initiator and a fourth functional monomer are added, the temperature is maintained constant for 3 to 8 hours, and the cationic nanopolymer emulsion is obtained after cooling.

[0019] In some embodiments, based on 1 part of the total mass of the initiator, the mass fraction of the initiator added in step S3 is 0.4 to 0.6 parts, and the mass fraction of the initiator added in step S4 is 0.4 to 0.6 parts.

[0020] In some embodiments, the total amount of the initiator accounts for 0.1% by weight of the cationic nanopolymer emulsion.

[0021] In some embodiments, the initiator is an azo initiator.

[0022] In some embodiments, the azo initiator includes at least one of azobisisobutylamidine hydrochloride, azobisisobutylimidazoline hydrochloride, and 4,4'-azobis(4-cyanovaleric acid).

[0023] In some embodiments, in step S2, the pH of the first mixed solution is adjusted by adding NaOH solution.

[0024] The present invention also provides an application of a heat-resistant amphiphilic polymer emulsion film-forming protective agent. The heat-resistant amphiphilic polymer emulsion film-forming protective agent is used in drilling fluid, and the addition amount in the drilling fluid is 1 wt% to 2 wt%.

[0025] The beneficial effects of the present invention are as follows: the heat-resistant amphiphilic polymer emulsion film-forming protective agent of the present invention is prepared by using the first functional monomer, the second functional monomer, the third functional monomer and the fourth functional monomer as main raw materials, and has excellent high-temperature resistance and excellent inhibitory properties. It can effectively block the multi-scale pores in the high-temperature reservoir section, inhibit the hydration expansion of shale, and improve the reservoir protection performance of water-based drilling fluid. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0027] Figure 1 It is a graph showing the effect of the embodiments and comparative examples of the present invention on the expansion performance of bentonite. DETAILED DESCRIPTION

[0028] The heat-resistant amphiphilic polymer emulsion film-forming protective agent of the present invention is a cationic nano polymer emulsion. The raw materials of the cationic nano polymer emulsion include a first functional monomer, a second functional monomer, a third functional monomer and a fourth functional monomer.

[0029] The molecular structure of the first functional monomer is shown in the following formula (1):

[0030]

[0031] In formula (1), R1 is H or methyl, and R2 is selected from any one of ethyl ester, butyl ester, and isooctyl ester. Depending on the selection of R1 and R2, the first functional monomer can be ethyl acrylate, butyl acrylate, isooctyl acrylate, ethyl methacrylate, butyl methacrylate, or isooctyl methacrylate.

[0032] The second functional monomer is styrene, and its molecular structure is shown in the following formula (II):

[0033]

[0034] The molecular structure of the third functional monomer is shown in the following formula (III):

[0035]

[0036] In formula (III), R3 is a p-phenylene group or a 2-amido-2-methylpropyl group. When R3 is a p-phenylene group, the third functional monomer is sodium p-styrene sulfonate; when R3 is a 2-amido-2-methylpropyl group, the third functional monomer is sodium 2-acrylamido-2-methylpropanesulfonate (AMPS-Na).

[0037] The molecular structure of the fourth functional monomer is shown in the following formula (IV):

[0038]

[0039] In formula (IV), R4 is H or methyl, the structure formed by R5 and the alkenyl group is selected from any one of vinyl, acrylamidopropyl, and acryloxyethyl, and X- is an anion selected from any one of chloride ion (Cl-), bromide ion (Br-), iodide ion (I-) or sulfonate anion (such as CH3SO3-).

[0040] According to the selection of R4 and R5, the fourth functional monomer is methacryloyloxyethyltrimethylammonium chloride, acryloyloxyethyltrimethylammonium chloride, methacryloyloxypropyltrimethylammonium chloride, methacryloyloxyethyltrimethylammonium bromide, methacryloyloxypropyltrimethylammonium bromide, methacryloyloxyethyltrimethylammonium iodide, methacryloyloxypropyltrimethylammonium iodide, acryloyloxyethyltrimethylammonium methanesulfonate or methacryloyloxyethyltrimethylammonium methanesulfonate.

[0041] According to the selection of the first to fourth functional monomers, the polymer molecular structure of the cationic nanopolymer emulsion is shown in the following formula (V):

[0042]

[0043] Wherein, R1, R2, R3, R4 and R5 are selected from the first to fourth functional monomers respectively. x:y:z:p is 18-29:43-74:1:1.

[0044] In the heat-resistant amphiphilic polymer emulsion film-forming protective agent (i.e., cationic nano polymer emulsion) of the present invention, a first functional monomer and a second functional monomer serve as the heat-resistant amphiphilic polymer emulsion film-forming protective agent matrix. The first functional monomer is a soft monomer, and the second functional monomer is a hard monomer. The two monomers are added in an appropriate ratio to give the cationic nano polymer emulsion a certain degree of flexibility. The third functional monomer mainly plays a high-temperature resistance function in the cationic nano polymer emulsion, and the fourth functional monomer mainly plays a swelling inhibition function in the cationic nano polymer emulsion.

[0045] In some embodiments, the mass ratio of the first functional monomer, the second functional monomer, the third functional monomer, and the fourth functional monomer is 15-25:30-50:1-2:1-2.

[0046] Preferably, the mass ratio of the first functional monomer, the second functional monomer, the third functional monomer and the fourth functional monomer is 10:20:1.5-1.8:1.5.

[0047] The preparation method of one embodiment of the heat-resistant amphiphilic polymer emulsion film-forming protective agent of the present invention may include the following steps:

[0048] S1. Mixing a first functional monomer, a second functional monomer, and a third functional monomer to form a first mixed solution.

[0049] S2. Adding NaOH solution to the first mixed solution, adjusting the pH to 8-9, and then stirring the mixture through high-speed mechanical stirring to form a stable emulsion.

[0050] S3. Heat the stable emulsion to 50°C to 60°C, add the initiator and maintain for 10 minutes to 30 minutes.

[0051] S4, heating the reaction system formed by the stable emulsion and the initiator in step S3 to 70° C. to 75° C., adding the initiator and the fourth functional monomer, maintaining the constant temperature for 3 to 8 hours, and cooling to obtain the cationic nanopolymer emulsion.

[0052] In some embodiments, the initiator added in steps S3 and S4 is the same, and the total amount of the initiator is 0.1% by weight of the cationic nanopolymer emulsion.

[0053] Based on 1 part of the total mass of the initiator, the mass fraction of the initiator added in step S3 is 0.4 to 0.6 parts, and the mass fraction of the initiator added in step S4 is 0.4 to 0.6 parts.

[0054] The initiator is preferably a water-soluble cationic initiator, mainly an azo initiator, which includes at least one of azobisisobutylamidine hydrochloride, azobisisobutylimidazoline hydrochloride, and 4,4'-azobis(4-cyanovaleric acid).

[0055] The heat-resistant amphiphilic polymer emulsion film-forming protective agent of the present invention is used in drilling fluid as an auxiliary agent of the drilling fluid. The addition amount of the film-forming protective agent in the drilling fluid is 1 wt% to 2 wt%, preferably 2 wt%.

[0056] The drilling fluid added with the temperature-resistant amphiphilic polymer emulsion film-forming protective agent can be used in high-temperature reservoir sections. The temperature-resistant amphiphilic polymer emulsion film-forming protective agent mainly plays a plugging role and effectively blocks the multi-scale pores in the high-temperature reservoir section.

[0057] When the drilling fluid added with the temperature-resistant amphiphilic polymer emulsion film-forming protective agent is used in shale reservoirs, the temperature-resistant amphiphilic polymer emulsion film-forming protective agent mainly plays a role in inhibiting expansion and inhibiting the hydration expansion of the shale.

[0058] It can be understood that when the drilling fluid to which the heat-resistant amphiphilic polymer emulsion film-forming protective agent is added is used in the high-temperature reservoir section, it does not exclude the heat-resistant amphiphilic polymer emulsion film-forming protective agent from playing an inhibitory role in expansion; when used in the shale reservoir, it does not exclude the heat-resistant amphiphilic polymer emulsion film-forming protective agent from playing a plugging role.

[0059] The present invention will be further described below by means of specific examples.

[0060] Example 1:

[0061] The first functional monomer is butyl methacrylate, the second functional monomer is styrene, the third functional monomer is sodium p-styrene sulfonate, and the fourth functional monomer is methacryloyloxyethyl trimethylammonium chloride.

[0062] The preparation method of cationic nano polymer emulsion is as follows:

[0063] a. Mix 20g of butyl methacrylate, 40g of styrene, and 1.5g of sodium p-styrene sulfonate and adjust the pH to 8-9;

[0064] b. Forming a stable emulsion through high-speed mechanical stirring;

[0065] c. The stable emulsion was placed in a three-necked flask and heated to 50-60°C, followed by the addition of 0.1 g of azobisisobutylamidine hydrochloride and maintained for 10-30 min;

[0066] d. The reaction system formed in step c was heated to 70-75°C, followed by the addition of 0.1 g of azobisisobutylamidine hydrochloride and 1.5 g of methacryloyloxyethyltrimethylammonium chloride. The temperature was maintained for 3-8 hours, and the cationic nanopolymer emulsion was obtained after cooling.

[0067] Example 2:

[0068] The first functional monomer is methyl methacrylate, the second functional monomer is styrene, the third functional monomer is sodium p-styrene sulfonate, and the fourth functional monomer is acrylamidopropyltrimethylammonium chloride.

[0069] The preparation method of cationic nano polymer emulsion is:

[0070] a. Mix 20g of methyl methacrylate, 40g of styrene, and 1.8g of sodium p-styrene sulfonate and adjust the pH to 8-9;

[0071] b. Forming a stable emulsion through high-speed mechanical stirring;

[0072] c. The stable emulsion was placed in a three-necked flask and heated to 50-60°C, followed by the addition of 0.1 g of azobisisobutylamidine hydrochloride and maintained for 10-30 min;

[0073] d. The reaction system formed in step c was heated to 70-75°C, followed by the addition of 0.1 g of azobisisobutylamidine hydrochloride and 1.8 g of acrylamidopropyltrimethylammonium chloride. The temperature was maintained for 3-8 hours, and the cationic nanopolymer emulsion was obtained after cooling.

[0074] Comparative Example 1:

[0075] The first functional monomer is butyl methacrylate, the second functional monomer is styrene, the third functional monomer is sodium p-styrene sulfonate, and the fourth functional monomer is not included.

[0076] a. Mix 20g of butyl methacrylate, 40g of styrene, and 1.8g of sodium p-styrene sulfonate and adjust the pH to 8-9;

[0077] b. Forming a stable emulsion through high-speed mechanical stirring;

[0078] c. The emulsion was placed in a three-necked flask and heated to 50-60°C, followed by the addition of 0.1 g of azobisisobutylamidine hydrochloride and maintained for 10-30 min;

[0079] d. The reaction system formed in c is further heated to 70-75°C, followed by adding 0.1 g of azobisisobutylamidine hydrochloride and maintaining the temperature for 3-8 hours. After cooling, a nanopolymer emulsion is obtained.

[0080] Comparative Example 2:

[0081] The first functional monomer is butyl methacrylate, the second functional monomer is styrene, the fourth functional monomer is acrylamidopropyltrimethylammonium chloride, and the third functional monomer is not included.

[0082] a. Mix 20g of butyl methacrylate and 40g of styrene;

[0083] b. Forming a stable emulsion through high-speed mechanical stirring;

[0084] c. The emulsion was placed in a three-necked flask and heated to 50-60°C, followed by the addition of 0.1 g of azobisisobutylamidine hydrochloride and maintained for 10-30 min;

[0085] d. The reaction system formed in c. is further heated to 70-75°C, followed by the addition of 0.1 g of azobisisobutylamidine hydrochloride and 1.8 g of acrylamidopropyltrimethylammonium chloride. The temperature is maintained for 3-8 hours, and the cationic nanopolymer emulsion is obtained after cooling.

[0086] The performance of the cationic nanopolymer emulsions prepared in Example 1, Example 2 and Comparative Example 1, Comparative Example 2 is tested below.

[0087] 1. Inhibition performance test:

[0088] The cationic nanopolymer emulsions prepared in Example 1, Example 2, and Comparative Example 1 and Comparative Example 2 were added to clean water at an addition amount of 1 wt%, and then a linear expansion test was performed according to the standard "NB / T 10121-2018 Evaluation Method for Shale Inhibition of Drilling Fluids". The effect of cationic nanopolymer emulsions on the expansion performance of bentonite was tested. The expansion height curve is shown in FIG. Figure 1 shown. Figure 1 In the figure, curve 1 and curve 2 correspond to Example 1 and Example 2, respectively, and curve 3 and curve 4 correspond to Comparative Example 1 and Comparative Example 2, respectively. It can be seen from the figure that the cationic nanopolymer emulsions of Example 1 and Example 2 can effectively inhibit the expansion of clay, and the expansion height is less than 3.5 mm.

[0089] After testing, adding 2 wt % of the cationic nanopolymer emulsion of Example 1 or Example 2 can also effectively inhibit clay swelling, which is omitted in the figure.

[0090] 2. Temperature resistance test:

[0091] The cationic nanopolymer emulsions prepared in Examples 1 and 2 and Comparative Examples 1 and 2 were added to 4% bentonite-based slurry at a dosage of 2 wt %, and sealed and aged at 180 ° C for 24 h. The system rheology and filtration loss properties were evaluated according to the "SY / T7377-2017 Drilling Fluid Design Specification". The test results are shown in Table 1.

[0092] Table 1. Rheological and filtration test data of different systems

[0093]

[0094] Test results show that the 4% bentonite slurry + 2wt% Example 1 maintains rheological stability while effectively reducing fluid loss. The addition of the nanopolymer emulsion improves the high-temperature sedimentation stability of the bentonite slurry. In Comparative Example 2, which lacks the third functional monomer, the lack of a heat-resistant monomer leads to reduced rheological and fluid loss properties after aging in the bentonite slurry.

[0095] 3. Plugging performance test:

[0096] The cationic nanopolymer emulsions prepared in Examples 1 and 2 and Comparative Examples 1 and 2 were added to 4% bentonite-based slurry at a dosage of 2 wt %. After sealing and aging at 180° C. for 24 h, the plugging performance of the 3D to 6D sand trays was evaluated using a high-temperature and high-pressure plugging instrument. The cumulative leakage was recorded over time and pressure data. The results are shown in Tables 2 to 5.

[0097] Table 2. Cumulative leakage over time and pressure data for plugging 3-6D sand disks in Example 1

[0098]

[0099] Table 3. Cumulative leakage over time and pressure data for plugging 3-6D sand disks in Example 2

[0100]

[0101] Table 4. Comparative Example 1 plugging 3-6D sand disk, cumulative leakage data over time and pressure

[0102]

[0103]

[0104] Table 5. Comparative Example 2 plugging 3-6D sand disk, cumulative leakage data over time and pressure

[0105]

[0106] From the data in Tables 2 to 5, it can be seen that the 4% bentonite slurry + 2wt% plugging system of Examples 1 and 2 has a good plugging effect on 3-6D sand trays. The instantaneous leakage and final leakage both decrease with the decrease of the sand tray permeability, and both can effectively withstand a pressure of more than 6.89 MPa.

[0107] 3. Evaluation of the reservoir protection performance of water-based drilling fluid:

[0108] With reference to the "Indoor Evaluation Method for Damage to Reservoirs by Drilling and Completion Fluids" (Petroleum and Natural Gas Industry Standard SY / T6540-2010), the reservoir protection performance of water-based drilling fluids of Example 1, Example 2, and Comparative Example 1 and Comparative Example 2 was evaluated. The results are shown in Table 6 below.

[0109] Table 6. Evaluation results of the reservoir protection performance of water-based drilling fluids in various embodiments and comparative examples

[0110]

[0111]

[0112] From the results in Table 6, it can be seen that the final damage rate of Example 1 is 49.81%, and the final damage rate of Example 2 is 44.58%, which are much lower than 80.75% of Comparative Example 1 and 78.46% of Comparative Example 2, indicating that the cationic nanopolymer emulsion prepared in the examples significantly reduces the degree of core contamination compared with the nanopolymer emulsion prepared in the comparative examples, and can effectively protect the reservoir.

[0113] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention's description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A heat-resistant amphiphilic polymer emulsion film-forming protective agent, characterized in that: The heat-resistant amphiphilic polymer emulsion film-forming protective agent is a cationic nano polymer emulsion, and its raw materials include a first functional monomer, a second functional monomer, a third functional monomer, and a fourth functional monomer. The molecular structures of the first functional monomer, the second functional monomer, the third functional monomer, and the fourth functional monomer are respectively shown in the following formulas (1) to (4): Wherein, R1 is H or methyl, R2 is selected from any one of ethyl ester, butyl ester, and isooctyl ester, R3 is para-phenylene or 2-amido-2-methylpropyl, R4 is H or methyl, the structure formed by R5 and the alkenyl group is selected from any one of vinyl, acrylamidopropyl, and acryloxyethyl, and X- is an anion selected from any one of chloride, bromide, iodide, and sulfonate anions.

2. The heat-resistant amphiphilic polymer emulsion film-forming protective agent according to claim 1, characterized in that: The polymer molecular structure of the cationic nanopolymer emulsion is shown in the following formula (V): Among them, x:y:z:p is 18-29:43-74:1:

1.

3. The heat-resistant amphiphilic polymer emulsion film-forming protective agent according to claim 1, characterized in that: The mass ratio of the first functional monomer, the second functional monomer, the third functional monomer and the fourth functional monomer is 15-25:30-50:1-2:1-2.

4. A method for preparing the temperature-resistant amphiphilic polymer emulsion film-forming protective agent according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1, mixing the first functional monomer, the second functional monomer and the third functional monomer to form a first mixed solution; S2, adjusting the pH of the first mixed solution to 8-9, and stirring to form a stable emulsion; S3, heating the stable emulsion to 50° C. to 60° C., adding an initiator and maintaining the temperature for 10 min to 30 min; S4. The stable emulsion is heated to 70° C. to 75° C., an initiator and a fourth functional monomer are added, the temperature is maintained constant for 3 to 8 hours, and the cationic nanopolymer emulsion is obtained after cooling.

5. The method for preparing the heat-resistant amphiphilic polymer emulsion film-forming protective agent according to claim 4, characterized in that: Based on 1 part of the total mass of the initiator, the mass fraction of the initiator added in step S3 is 0.4 to 0.6 parts, and the mass fraction of the initiator added in step S4 is 0.4 to 0.6 parts.

6. The method for preparing the heat-resistant amphiphilic polymer emulsion film-forming protective agent according to claim 5, characterized in that: The total amount of the initiator accounts for 0.1% by mass of the cationic nano polymer emulsion.

7. The method for preparing the heat-resistant amphiphilic polymer emulsion film-forming protective agent according to claim 4, characterized in that: The initiator is an azo initiator.

8. The method for preparing the heat-resistant amphiphilic polymer emulsion film-forming protective agent according to claim 7, characterized in that: The azo initiator includes at least one of azobisisobutylamidine hydrochloride, azobisisobutylimidazoline hydrochloride, and 4,4'-azobis(4-cyanovaleric acid).

9. The method for preparing the heat-resistant amphiphilic polymer emulsion film-forming protective agent according to claim 4, characterized in that: In step S2, the pH of the first mixed solution is adjusted by adding NaOH solution.

10. Use of the heat-resistant amphiphilic polymer emulsion film-forming protective agent according to any one of claims 1 to 3, characterized in that: The temperature-resistant amphiphilic polymer emulsion film-forming protective agent is used in drilling fluid, and its added amount in the drilling fluid is 1 wt% to 2 wt%.

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