A clay anti-swell composition, its preparation and use

Abstract

The application provides a clay anti-swelling agent composition and a preparation method and application thereof, and the clay anti-swelling agent composition comprises, in mass fraction, 5-20 wt% of polyether amine, 15-30 wt% of an organic ammonium salt, 8-16 wt% of a low-molecular-weight cationic polymer, 10-20 wt% of a polyvinylamine and 5-10 wt% of an organic acid, and the rest is water; the clay anti-swelling agent composition has the advantages of good anti-swelling effect, long-acting effect, prevention of clay particle migration, good temperature resistance, non-increase of formation water salinity, increase of formation permeability and the like, the anti-swelling rate is greater than or equal to 90%, the anti-swelling rate is greater than or equal to 92% after aging at 350 DEG C, the water washing resistance rate is 100%, the core permeability recovery rate is greater than or equal to 75%, and the core permeability retention rate is greater than or equal to 85%.

Description

A clay anti-swelling agent composition, its preparation method and application Technical Field

[0001] This invention belongs to the field of oilfield engineering technology, specifically relating to a clay anti-swelling agent composition, its preparation method, and its application. Background Technology

[0002] Clay is a common mineral found in geological formations. Because clay swells when exposed to water, during reservoir development processes such as water injection, acidizing, or fracturing in oilfields, the porosity in clay-rich reservoirs decreases due to clay expansion, leading to significant pore blockage and water-sensitive damage. To mitigate this reservoir damage, clay anti-swelling agents are widely used. These agents effectively adsorb onto the clay surface, preventing the hydration, expansion, and dispersion of water-sensitive minerals within the reservoir, thus preventing damage to the oil and gas layer and impacting oilfield development.

[0003] With the improvement of oilfield exploitation technology, the application of clay anti-swelling agents has become more and more widespread and the types are increasing. According to the different chemical composition and mechanism of action, there are three main stages: (1) the early stage of inorganic salt clay anti-swelling agents, which mainly utilizes inorganic salt ions such as K+ to embed into the clay crystal structure to neutralize electronegativity; (2) in the 1970s, inorganic polynuclear polymers and cationic surfactants were used to stabilize clay and form a hydrophobic layer on the surface of clay particles to prevent further hydration of clay; (3) after the 1980s, research and experiments were mainly carried out on stabilizing clay with cationic organic polymers. Representative products include cationic polyacrylamide with a certain molecular weight, polyamine compounds and hyperbranched molecules, etc.

[0004] CN105505341B discloses a clay swelling inhibitor, which mainly comprises three types of substances: ammonium salt, polyol, and potassium formate. The components, by mass percentage, are: ammonium salt: 20–60.0%; polyol: 2.0–30.0%; potassium formate: 2.0–10%; with the balance being water. This clay swelling inhibitor exhibits excellent temperature resistance and good swelling prevention performance, making it suitable for low-permeability reservoirs.

[0005] CN113088265A discloses a high-temperature resistant and efficient clay stabilizer, mainly containing three substances: organic amine, hexadecyltrimethylammonium chloride, and potassium chloride. The clay stabilizer provided by this invention can withstand temperatures up to 300℃, exhibiting not only strong anti-swelling ability but also shrinkage-swelling ability. It can be applied to water injection, acidizing, fracturing, and also in heavy oil thermal recovery.

[0006] CN108977190B discloses a small-molecule liquid anti-swelling agent, a clay anti-swelling agent for fracturing, and a preparation method thereof. The anti-swelling agent comprises the following components by weight percentage: 10-65% alkyl hydroxypropyl quaternary ammonium salt, 1-10% guanidine hydrochloride, 1-10% nonionic surfactant, and the balance being water. The nonionic surfactant is an alkylphenol polyoxyethylene ether or a fatty alcohol polyoxyethylene ether with 8-18 hydrocarbon carbon atoms and a degree of polymerization of 8-20. The liquid anti-swelling agent of this invention is composed of small-molecule components, featuring low relative molecular weight, non-damaging to oil and gas reservoirs, and convenient on-site preparation. It exhibits high anti-swelling efficiency with low dosage; the anti-swelling efficiency of the aqueous solution can reach 71%, and after compounding with inorganic salts, the anti-swelling efficiency reaches 79%. It is particularly suitable for fracturing stimulation of low-permeability, water-sensitive formations.

[0007] CN106947440A discloses a temperature- and salt-resistant anti-swelling clay stabilizer and its preparation method. This anti-swelling clay stabilizer is a compound composed of soybean oil-modified surfactant, aminocarboxylic acid resin, ammonium sulfate, and water. The soybean oil-modified surfactant is a quaternary ammonium salt surfactant with long-chain alkyl groups and quaternary ammonium cations. The anti-swelling clay stabilizer of this invention has the advantages of wide availability of raw materials, simple synthesis process, low dosage, and strong reservoir adaptability. It also exhibits good temperature and salt resistance, withstanding temperatures up to 280℃ and mineralization up to 230,000 mg / L. Furthermore, it has good compatibility with formation water and a high anti-swelling rate of over 98.0%.

[0008] While the aforementioned clay anti-swelling agents all exhibit good anti-swelling effects, their formulations all utilize inorganic salts. Inorganic salts, on the one hand, increase the mineralization of formation water, hindering subsequent profile control; on the other hand, they merely neutralize the negative charge on the clay surface with their positive charge, compressing and diffusing the electric double layer to compact clay particles, without binding the clay to the formation. Therefore, they fail to prevent clay migration or stabilize sand. Consequently, the amount of inorganic salts in clay anti-swelling agent formulations should be reduced, and the interaction between clay and formation should be enhanced by introducing low-molecular-weight cationic polymers. This would prevent both clay swelling and migration. Introducing low-molecular-weight polyetheramine compounds allows the amine groups to penetrate the clay interlayers, tightening the clay layers, displacing interlayer water molecules, and reducing clay hydration and dispersion. Summary of the Invention

[0009] To address the aforementioned problems in the prior art, this invention proposes a clay anti-swelling agent composition, its preparation method, and its application.

[0010] In a first aspect, the present invention provides a clay anti-swelling agent composition, wherein, by mass fraction, the composition comprises: 5-20 wt% polyetheramine, 15-30 wt% organic ammonium salt, 8-16 wt% low molecular weight cationic polymer, 10-20 wt% polyethyleneamine and 5-10 wt% organic acid, with the remainder being water.

[0011] As a specific embodiment of the present invention, the polyetheramine is a polyetheramine containing three or four primary amines.

[0012] As a specific embodiment of the present invention, the polyetheramine has the following structural formula:

[0013]

[0014] Where x, y, z, a, b, c, and d are any integers from 1 to 20, preferably any integers from 1 to 10;

[0015] R1 and R2 are each independently hydrogen or methyl.

[0016] As a specific embodiment of the present invention, the organic ammonium salt includes one or more of benzyltrimethylammonium chloride, 3-chloro-2-hydroxypropyltrimethylammonium chloride, glycidyltrimethylammonium chloride, and tetramethylammonium chloride.

[0017] As a specific embodiment of the present invention, the low molecular weight cationic polymerization includes one or both of dimethyl diallyl ammonium chloride homopolymer and copolymer of dimethyl diallyl ammonium chloride and acrylamide.

[0018] As a specific embodiment of the present invention, the viscosity-average molecular weight of the low molecular weight cationic polymer is 0.5 to 300,000, preferably 200,000 to 200,000, and more preferably 50,000 to 150,000.

[0019] As a specific embodiment of the present invention, the cationicity of the copolymer of dimethyl diallyl ammonium chloride and acrylamide is 20-60 wt%, preferably 30-50 wt%.

[0020] As a specific embodiment of the present invention, the polyethyleneamine includes one or more of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, and polyethylenepolyamine.

[0021] As a specific embodiment of the present invention, the organic acid includes one or more of formic acid, acetic acid, citric acid and oxalic acid.

[0022] Secondly, the present invention provides a method for preparing the clay anti-swelling agent composition, comprising the following steps:

[0023] S1: Mix polyetheramine, organic ammonium salt solution, low molecular weight cationic polymer solution and polyethyleneamine to obtain the first mixture;

[0024] S2: Add organic acid to the first mixture obtained in step S1, and react to obtain a clay anti-swelling agent composition.

[0025] As a specific embodiment of the present invention, the mixing conditions in step S1 include: a temperature of 20-25°C, a stirring speed of 200-500 rpm, and a stirring time of 10-40 min; the reaction conditions in step S2 include: a temperature of 30-50°C, a stirring speed of 400-800 rpm, and a stirring time of 30-60 min. The organic acid is preferably added to the first mixture by dropping, and the dropping rate is preferably 10-100 mL / h.

[0026] Thirdly, the present invention provides the application of the clay anti-swelling agent composition in the field of oil production engineering.

[0027] All of the above-mentioned raw materials used in this invention can be prepared in-house or purchased commercially; this invention does not impose any particular limitations on them.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] 1. The clay anti-swelling agent composition of the present invention contains amine groups, which can enter the clay sheet structure, tighten the sheets, displace water molecules between the layers, and prevent the clay sheets from peeling off.

[0030] 2. The clay anti-swelling agent composition of the present invention has a high charge density, effectively neutralizes the negative charge on the clay surface, increases the Zeta potential of clay particles, enhances anti-swelling performance, and has an anti-swelling rate of ≥90%, and an anti-swelling rate of ≥92% after aging at 350℃.

[0031] 3. The clay anti-swelling agent composition of the present invention has strong adsorption with clay, has a long-lasting anti-swelling effect and prevents clay migration, has a water washability of 100%, a core permeability recovery rate of ≥75%, and a core permeability retention rate of ≥85%.

[0032] 4. The clay anti-swelling agent composition of the present invention does not contain inorganic salts, will not increase the mineralization of formation water, and has no adverse effect on subsequent water shut-off and profile control agents. Detailed Implementation

[0033] The present invention will be further described below with reference to specific embodiments, but this does not constitute any limitation on the present invention.

[0034] Example 1

[0035] This embodiment provides a clay anti-swelling agent composition, the specific details of which are as follows:

[0036] A four-necked flask equipped with a stirrer, thermometer, and constant-pressure dropping funnel was placed in a 20°C water bath. 20g of polyetheramine, 20g of a 40% (w / w) polydimethyldiallyl ammonium chloride solution with a viscosity-average molecular weight of 20,000, 40g of a 50% benzyltrimethylammonium chloride solution, and 12g of diethylenetriamine were added and stirred until homogeneous. The mixing temperature was maintained at 25°C, and stirring was continued at 200 rpm for 20 minutes. Then, the stirring speed was increased to 400 rpm, and 8g of formic acid was added dropwise at a rate of 10 mL / h while maintaining the flask temperature at 30°C. After the addition was complete, stirring was continued for 30 minutes to obtain clay anti-swelling agent composition 1. # The chemical structure of polyetheramine is as follows:

[0037]

[0038] Where: x=y=z=1, R1 is methyl, and R2 is hydrogen.

[0039] Example 2

[0040] This embodiment provides a clay anti-swelling agent composition, the specific details of which are as follows:

[0041] A four-necked flask equipped with a stirrer, thermometer, and constant-pressure dropping funnel was placed in a 20°C water bath. 5g of polyetheramine, 40g of a 40% (w / w) polydimethyldiallyl ammonium chloride solution with a viscosity-average molecular weight of 50,000, 40g of a 50% tetramethylammonium chloride solution, and 10g of triethylenetetramine were added and stirred until homogeneous. The mixing temperature was maintained at 20°C, and stirring was continued at 300 rpm for 10 minutes. Then, the stirring speed was increased to 500 rpm, and 5g of acetic acid was added dropwise at a rate of 50 mL / h while maintaining the flask temperature at 35°C. After the addition was complete, stirring was continued for 40 minutes to obtain clay anti-swelling agent composition 2. # The chemical structure of polyetheramine is as follows:

[0042]

[0043] Where: x = y = z = 3, R1 is hydrogen, and R2 is hydrogen.

[0044] Example 3

[0045] This embodiment provides a clay anti-swelling agent composition, the specific details of which are as follows:

[0046] A four-necked flask equipped with a stirrer, thermometer, and constant-pressure dropping funnel was placed in a 20°C water bath. 10g of polyetheramine, 30g of a 40% cationic polyacrylamide solution with a viscosity-average molecular weight of 50,000 and a cationicity of 40%, 45g of 50% 3-chloro-2-hydroxypropyltrimethylammonium chloride, and 10g of tetraethylenepentamine were added and stirred until homogeneous. The mixing temperature was maintained at 25°C, and stirring was continued at 100 rpm for 20 minutes. Then, the stirring speed was increased to 800 rpm, and 5g of formic acid was added dropwise at a rate of 60 mL / h while maintaining the flask temperature at 50°C. After the addition was complete, stirring was continued for 60 minutes to obtain clay anti-swelling agent composition 3. # The chemical structure of polyetheramine is as follows:

[0047]

[0048] Where: x=y=z=2, R1 is methyl, and R2 is hydrogen.

[0049] Example 4

[0050] This embodiment provides a clay anti-swelling agent composition, the specific details of which are as follows:

[0051] A four-necked flask equipped with a stirrer, thermometer, and constant-pressure dropping funnel was placed in a 20°C water bath. 10g of polyetheramine, 25g of a 40% (w / w) polydimethyldiallyl ammonium chloride solution with a viscosity-average molecular weight of 150,000, 50g of 50% glycidyltrimethylammonium chloride, and 10g of diethylenetriamine were added and stirred until homogeneous. The mixing temperature was maintained at 25°C, and stirring was continued at 400 rpm for 20 minutes. Then, the stirring speed was increased to 500 rpm, and 5g of citric acid was added dropwise at a rate of 60 mL / h while maintaining the flask temperature at 45°C. After the addition was complete, stirring was continued for 30 minutes to obtain clay anti-swelling agent composition 4. # The chemical structure of polyetheramine is as follows:

[0052]

[0053] Where: x=y=z=5, R1 is methyl, and R2 is hydrogen.

[0054] Example 5

[0055] This embodiment provides a clay anti-swelling agent composition, the specific details of which are as follows:

[0056] A four-necked flask equipped with a stirrer, thermometer, and constant-pressure dropping funnel was placed in a 20°C water bath. 15g of polyetheramine, 20g of a 40% (w / w) polydimethyldiallyl ammonium chloride solution with a viscosity-average molecular weight of 100,000, 40g of a 50% benzyltrimethylammonium chloride solution, and 15g of diethylenetriamine were added and stirred until homogeneous. The mixing temperature was maintained at 23°C, and stirring was continued at 300 rpm for 30 minutes. Then, the stirring speed was increased to 400 rpm, and 10g of oxalic acid was added dropwise at a rate of 40 mL / h while maintaining the flask temperature at 35°C. After the addition was complete, stirring was continued for 30 minutes to obtain clay anti-swelling agent composition 5. # The chemical structure of polyetheramine is as follows:

[0057]

[0058] Where: x=y=z=3, R1 is methyl, and R2 is hydrogen.

[0059] Example 6

[0060] This embodiment provides a clay anti-swelling agent composition, the specific details of which are as follows:

[0061] A four-necked flask equipped with a stirrer, thermometer, and constant-pressure dropping funnel was placed in a water bath. 20g of polyetheramine, 20g of a 40% cationic polyacrylamide solution with a viscosity-average molecular weight of 20,000 and a cationicity of 50%, 30g of 50% 3-chloro-2-hydroxypropyltrimethylammonium chloride, and 20g of polyethylenepolyamine were added and stirred until homogeneous. The mixing temperature was maintained at 25°C, and stirring was continued at 200 rpm for 20 minutes. Then, the stirring speed was increased to 400 rpm, and 10g of formic acid was added dropwise at a rate of 20 mL / h while maintaining the flask temperature at 25°C. After the addition was complete, stirring was continued for 60 minutes to obtain clay anti-swelling agent composition 6. # The chemical structure of polyetheramine is as follows:

[0062]

[0063] Where: a=b=c=d=1, R1 is methyl, and R2 is hydrogen.

[0064] Example 7

[0065] This embodiment provides a clay anti-swelling agent composition, the specific details of which are as follows:

[0066] A four-necked flask equipped with a stirrer, thermometer, and constant-pressure dropping funnel was placed in a 20°C water bath. 5g of polyetheramine, 35g of a 40% (w / w) polydimethyldiallyl ammonium chloride solution with a viscosity-average molecular weight of 300,000, 40g of a 50% benzyltrimethylammonium chloride solution, and 13g of triethylenetetramine were added and stirred until homogeneous. The mixing temperature was maintained at 25°C, and stirring was continued at 300 rpm for 40 min. Then, the stirring speed was increased to 600 rpm, and 7g of acetic acid was added dropwise at a rate of 40 mL / h while maintaining the flask temperature at 35°C. After the addition was complete, stirring was continued for 60 min to obtain the clay anti-swelling agent composition 7. # The chemical structure of polyetheramine is as follows:

[0067]

[0068] Where: a=b=c=d=5, R1 is hydrogen, R2 is hydrogen.

[0069] Example 8

[0070] This embodiment provides a clay anti-swelling agent composition, the specific details of which are as follows:

[0071] A four-necked flask equipped with a stirrer, thermometer, and constant-pressure dropping funnel was placed in a 20°C water bath. 10g of polyetheramine, 40g of a 40% (w / w) polydimethyldiallyl ammonium chloride solution with a viscosity-average molecular weight of 0.5 million, 35g of a 50% tetramethylammonium chloride solution, and 10g of diethylenetriamine were added and stirred until homogeneous. The mixing temperature was maintained at 20°C, and stirring was continued at 200 rpm for 30 minutes. Then, the stirring speed was increased to 400 rpm, and 5g of citric acid was added dropwise at a rate of 30 mL / h while maintaining the flask temperature at 45°C. After the addition was complete, stirring was continued for 30 minutes to obtain clay anti-swelling agent composition 8. # The chemical structure of polyetheramine is as follows:

[0072]

[0073] Where: a=b=c=d=1, R1 is hydrogen, and R2 is methyl.

[0074] Example 9

[0075] This embodiment provides a clay anti-swelling agent composition, the specific details of which are as follows:

[0076] A four-necked flask equipped with a stirrer, thermometer, and constant-pressure dropping funnel was placed in a 20°C water bath. 12g of polyetheramine, 25g of a 40% (w / w) polydimethyldiallyl ammonium chloride solution with a viscosity-average molecular weight of 150,000, 35g of a 50% benzyltrimethylammonium chloride solution, and 18g of diethylenetriamine were added and stirred until homogeneous. The mixing temperature was maintained at 25°C, and stirring was continued at 500 rpm for 20 minutes. Then, the stirring speed was increased to 800 rpm, and 10g of acetic acid was added dropwise at a rate of 100 mL / hn while maintaining the flask temperature at 20°C. After the addition was complete, stirring was continued for 60 minutes to obtain clay anti-swelling agent composition 9. # The chemical structure of polyetheramine is as follows:

[0077]

[0078] Where: a=b=c=d=2, R1 is methyl, and R2 is hydrogen.

[0079] Example 10

[0080] This embodiment provides a clay anti-swelling agent composition, the specific details of which are as follows:

[0081] A four-necked flask equipped with a stirrer, thermometer, and constant-pressure dropping funnel was placed in a 20°C water bath. 5g of polyetheramine, 20g of a 40% cationic polyacrylamide solution with a viscosity-average molecular weight of 200,000 and a cationicity of 30%, 60g of a 50% benzyltrimethylammonium chloride solution, and 10g of diethylenetriamine were added and stirred until homogeneous. The mixing temperature was maintained at 25°C, and stirring was continued at 200 rpm for 10 minutes. Then, the stirring speed was increased to 400 rpm, and 5g of formic acid was added dropwise at a rate of 80 mL / h while maintaining the flask temperature at 25°C. After the addition was complete, stirring was continued for 30 minutes to obtain a clay anti-swelling agent composition 10. # The chemical structure of polyetheramine is as follows:

[0082]

[0083] Where: a=b=c=d=3, R1 is methyl, and R2 is hydrogen.

[0084] Comparative Example 1

[0085] Following the method of Example 1, except that 20g of polyetheramine, 10g of a 40% (by mass) polydimethyldiallylammonium chloride solution with a viscosity-average molecular weight of 20,000, 50g of a 50% benzyltrimethylammonium chloride solution, and 12g of diethylenetriamine were used, and other conditions were the same as in Example 1, clay anti-swelling agent composition D1 was prepared.

[0086] Comparative Example 2

[0087] Following the method of Example 1, except that 2g of polyetheramine, 30g of a 40% (by mass) polydimethyldiallylammonium chloride solution with a viscosity-average molecular weight of 20,000, 48g of a 50% benzyltrimethylammonium chloride solution, and 12g of diethylenetriamine were used, and other conditions were the same as in Example 1, clay anti-swelling agent composition D2 was prepared.

[0088] Comparative Example 3

[0089] Following the method of Example 1, except that polyacrylamide was used instead of polydimethyldiallylammonium chloride, and other conditions were the same as in Example 1, clay anti-swelling agent composition D3 was prepared.

[0090] Comparative Example 4

[0091] Following the method of Example 1, except that polyether alcohol was used instead of polyether amine, and other conditions were the same as in Example 1, clay anti-swelling agent composition D4 was prepared.

[0092] Test Example 1

[0093] The anti-swelling properties and temperature resistance of the clay anti-swelling agent compositions prepared in Examples 1-10 were evaluated by room temperature anti-swelling rate and high temperature anti-swelling rate experiments. The erosion resistance of the clay anti-swelling agent compositions was evaluated by water washing resistance test. The specific test steps are as follows, and the results are shown in Table 1.

[0094] The anti-swelling rate was tested according to the "Sy / T5971-2016 Performance Evaluation Method of Clay Stabilizer for Water Injection". The steps were as follows: Weigh 0.5g of sodium bentonite, add it to a 10mL centrifuge tube, add deionized water to the 10mL mark, shake thoroughly, let stand at room temperature for 2 hours, put it into a centrifuge, and centrifuge at 1500r / min for 15 minutes. Read the volume V2 of sodium bentonite in water. Use the same steps but replace water with a 2% clay anti-swelling agent aqueous solution to measure the volume V1 of the soil after centrifugation. Use kerosene instead of water to measure the volume V0 of the soil.

[0095] The calculation formula is shown in Equation 1.

[0096]

[0097] Where: η—anti-swelling rate, %;

[0098] V0—Volume of sodium bentonite in kerosene, mL;

[0099] V1—Volume of sodium bentonite in clay anti-swelling agent, mL;

[0100] V2—Volume of sodium bentonite in pure water, mL.

[0101] The steps for testing the anti-swelling rate after aging at 350℃ are as follows: Add 3.00g of sodium bentonite to 60mL of a 3% (w / v) clay anti-swelling agent solution, shake thoroughly to mix, and then place in an aging vessel; then place in a high-temperature aging furnace and age at 350±2℃ for 24h; after cooling to room temperature, transfer all the clay anti-swelling agent solution in the aging vessel to a 100mL beaker, shake thoroughly, quickly remove 10mL and add it to a centrifuge tube, place it in a centrifuge with an automatic balancing function, centrifuge at 1500r / min for 15min, and read the swelling volume V1 of the bentonite. The formula for calculating the high-temperature anti-swelling rate is shown in Equation 2.

[0102]

[0103] Where: F—high temperature anti-swelling rate, %;

[0104] V0—Volume of sodium bentonite in kerosene, mL;

[0105] V1—Volume of sodium bentonite in clay anti-swelling agent, mL;

[0106] V2—Volume of sodium bentonite in pure water, mL.

[0107] The test procedure for water washability is as follows: Pour out the supernatant from the centrifuge tube after the anti-swelling rate test, add deionized water to 10 mL, stir thoroughly, let stand for 2 hours, and then centrifuge at 1500 r / min for 15 min. Read the final volume V1′ of sodium bentonite in the centrifuge tube. The formula for calculating the water washability rate is shown in Equation 3.

[0108]

[0109] Where: V1—the swelling volume of sodium bentonite in the aqueous solution of clay anti-swelling agent, mL;

[0110] V1′—The swelling volume of sodium bentonite after washing with water, in mL;

[0111] V2—The volume of sodium bentonite that expands in pure water, in mL.

[0112] Table 1. Performance evaluation results of the clay anti-swelling agent compositions prepared in Examples 1-10

[0113]

[0114]

[0115] Test Example 2

[0116] Using a core displacement device, the performance of clay anti-swelling agent in restoring and maintaining formation permeability was evaluated through expansion treatment and expansion prevention experiments. The evaluation methods are as follows, and the results are shown in Table 2.

[0117] Swelling control experiment: Distilled water (300℃ high-temperature steam), clay anti-swelling agent, and distilled water (300℃ high-temperature steam) were sequentially injected into a core tube saturated with simulated formation water. The initial permeability Ko, the permeability Ki after distilled water (300℃ high-temperature steam), and the permeability K after injecting the anti-swelling agent and then injecting distilled water (300℃ high-temperature steam) were measured. The formation permeability recovery rate K / Ko was calculated.

[0118] Swelling prevention experiment: Clay anti-swelling agent and distilled water (300℃ high-temperature steam) were sequentially injected into the core tube after saturation with simulated formation water. The initial permeability Ko and the permeability Ki after injecting the anti-swelling agent and then distilled water (300℃ high-temperature steam) were measured. The formation permeability retention rate Ki / Ko was calculated.

[0119] Table 2. Effect of clay anti-swelling agent compositions prepared in Examples 1-10 on core permeability.

[0120]

[0121]

[0122] In summary, the clay anti-swelling agent composition of the present invention contains amine groups, which can penetrate the clay lamellar structure, tighten the lamellars, displace interlayer water molecules, and prevent the clay lamellars from peeling off. This clay anti-swelling agent composition has a high charge density, effectively neutralizing the negative charge on the clay surface, increasing the Zeta potential of clay particles, and enhancing anti-swelling performance, with an anti-swelling rate ≥90% and an anti-swelling rate ≥92% after aging at 350℃. This clay anti-swelling agent composition has strong adsorption to clay, providing a long-lasting anti-swelling effect and preventing clay migration. It exhibits 100% water wash resistance, a core permeability recovery rate ≥75%, and a core permeability retention rate ≥85%. Comparative data shows that reducing the amount of polyetheramine and cationic polymer in the composition reduces the effectiveness of the clay anti-swelling agent; replacing them with other commonly used anti-swelling agent components also significantly reduces their performance.

[0123] Any numerical value mentioned in this invention, if there is only a two-unit interval between any minimum and any maximum value, includes all values ​​that increase by one unit each time from the minimum to the maximum value. For example, if the amount of a component, or the value of a process variable such as temperature, pressure, or time, is stated as 50-90, in this specification it means specifically listing values ​​such as 51-89, 52-88… and 69-71 and 70-71, etc. For non-integer values, it may be appropriately considered that a unit is 0.1, 0.01, 0.001, or 0.0001. These are merely some specifically specified examples. In this application, in a similar manner, all possible combinations of numerical values ​​between the listed minimum and maximum values ​​are considered to have been disclosed.

[0124] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A clay anti-swelling agent composition, characterized in that, The composition comprises, by mass fraction: 5-20 wt% polyetheramine, 8-16 wt% low molecular weight cationic polymer, 15-30 wt% organic ammonium salt, 10-20 wt% polyethyleneamine, and 5-10 wt% organic acid, with the remainder being water; the low molecular weight cationic polymer has a viscosity-average molecular weight of 0.5-300,000; the polyetheramine has the following structural formula: Alternatively, the polyetheramine has the following structural formula: and Wherein, x, y, z, a, b, c, and d are any integers from 1 to 20, and R1 and R2 are each independently hydrogen or methyl; the polyethyleneamine includes one or more of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, and polyethylenepolyamine.

2. The clay anti-swelling agent composition according to claim 1, characterized in that, In the structure of the polyetheramine, x, y, z, a, b, c, and d are any integers from 1 to 10.

3. The clay anti-swelling agent composition according to claim 1 or 2, characterized in that, The organic ammonium salt includes one or more of benzyltrimethylammonium chloride, 3-chloro-2-hydroxypropyltrimethylammonium chloride, glycidyltrimethylammonium chloride, and tetramethylammonium chloride.

4. The clay anti-swelling agent composition according to claim 3, characterized in that, The low molecular weight cationic polymer includes one or both of dimethyl diallyl ammonium chloride homopolymer and a copolymer of dimethyl diallyl ammonium chloride and acrylamide; and / or, the cationicity of the copolymer of dimethyl diallyl ammonium chloride and acrylamide is 20-60 wt%.

5. The clay anti-swelling agent composition according to claim 4, characterized in that, The viscosity-average molecular weight of the low molecular weight cationic polymer is 20,000 to 200,000.

6. The clay anti-swelling agent composition according to claim 5, characterized in that, The viscosity-average molecular weight of the low molecular weight cationic polymer is 50,000 to 150,000.

7. The clay anti-swelling agent composition according to any one of claims 4-6, characterized in that, The cationicity of the copolymer of dimethyl diallyl ammonium chloride and acrylamide is 30-50 wt%.

8. The clay anti-swelling agent composition according to claim 7, characterized in that, The organic acids include one or more of formic acid, acetic acid, citric acid, and oxalic acid.

9. A method for preparing a clay anti-swelling agent composition according to any one of claims 1-8, characterized in that, Includes the following steps: S1: Mix polyetheramine, organic ammonium salt solution, low molecular weight cationic polymer solution and polyethyleneamine to obtain a first mixture; S2: Add organic acid to the first mixture obtained in step S1 and react to obtain a clay anti-swelling agent composition.

10. The preparation method according to claim 9, characterized in that, The mixing conditions in step S1 include: a temperature of 20~25℃, a stirring speed of 200-500rpm, and a stirring time of 10~40min; and / or the reaction conditions in step S2 include: a temperature of 30~50℃, a stirring speed of 400-800rpm, and a stirring time of 30~60min.

11. The preparation method according to claim 10, characterized in that, The organic acid is added to the first mixture dropwise at a rate of 10-100 mL / h.

12. The application of the clay anti-swelling agent composition according to any one of claims 1-8 or the clay anti-swelling agent composition prepared by any one of claims 9-11 in the field of oil production engineering.

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