Acidification blocking remover for oil field and preparation method of acidification blocking remover

Abstract

The invention discloses an acidification blocking remover for an oil field and a preparation method of the acidification blocking remover. The acidification blocking remover comprises the following raw materials in parts by weight: 40-60 parts of hydrochloric acid, 10-20 parts of hydrofluoric acid, 5-10 parts of fluoboric acid, 1-3 parts of a modified stabilizer, 0.1-0.5 part of imidazoline and 20-30 parts of water. The modified stabilizer contains a quaternary ammonium salt structure which can be combined with negative charges on the clay to form a modified stabilizer coating on the surface of the clay, a polysiloxane molecular chain on the modified stabilizer can form a layer of hydrophobic film on the surface, and due to incompatibility between water molecules and hydrophobic groups, the hydrophobic film repels water groups, so that the clay can be degraded. Alkyl long chains on the outer side are combined with a hydrophobic membrane formed by polysiloxane molecules to form a second layer of hydrophobic membrane, then a bimolecular membrane is formed on the surface of the clay, the hydrophobic effect of the bimolecular membrane is far higher than that of a traditional monomolecular membrane, external moisture is effectively prevented from entering clay particles, and hydration expansion of the clay is inhibited.

Description

Technical Field

[0001] This invention relates to the field of unblocking agent preparation technology, specifically to an acid unblocking agent for oilfields and its preparation method. Background Technology

[0002] In the later stages of water injection development in oilfields, due to factors such as formation and water quality, the injection formation becomes contaminated and clogged, leading to a gradual increase in injection pressure. The number of high-pressure injection wells, under-injection wells, and wells that fail to inject water increases year by year. High-pressure water injection increases safety hazards for equipment and personnel, as well as electricity consumption and injection costs. Acid injection unblocking technology utilizes chemical reaction principles, injecting acid into the well to dissolve or destroy the blocking substances, thereby restoring well flow and improving oil and gas field production. However, prolonged contact between acid or other fluids and the reservoir can cause clay minerals to expand, disperse, and migrate, severely affecting reservoir permeability and consequently reducing oil and gas production and recovery rates. Summary of the Invention

[0003] The purpose of this invention is to provide an acid plugging agent for oil fields and its preparation method, which solves the problem that clay will hydrate, expand, and disperse after the use of current acid plugging agents, thereby reducing the permeability of the reservoir.

[0004] The objective of this invention can be achieved through the following technical solutions: A method for preparing an acid plugging agent for oilfield use, specifically including the following steps: Step A1: Mix the modified polysiloxane, oleic acid, chloroplatinic acid and DMF evenly, purge with nitrogen, and react for 5-7 hours at a speed of 200-300 r / min and a temperature of 75-85℃ to obtain the stabilizer monomer. Step A2: Mix the stabilizer monomer, dimethylaminoethanol, p-toluenesulfonic acid and toluene evenly, and react for 3-5 hours at a speed of 200-300 r / min and a temperature of 110-115℃ to obtain the pretreated stabilizer. Step A3: Mix the pretreatment stabilizer, bromoethane, potassium iodide and DMF evenly, purge with nitrogen, and react for 20-25 hours at a speed of 200-300 r / min and a temperature of 95-100℃ to obtain the modified stabilizer. Step A4: Weigh the following raw materials in parts by weight: 40-60 parts hydrochloric acid, 10-20 parts hydrofluoric acid, 5-10 parts fluoroboric acid, 1-3 parts modified stabilizer, 0.1-0.5 parts imidazoline, and 20-30 parts water. Mix the raw materials evenly to obtain an acid plugging agent for oil fields.

[0005] Furthermore, the molar ratio of Si-H bonds on the modified polysiloxane to oleic acid in step A1 is 1:1, and the amount of chloroplatinic acid used is 1‰ of the mass of oleic acid.

[0006] Furthermore, in step A2, the molar ratio of the carboxyl group on the stabilizer monomer to dimethylaminoethanol is 1:1, and the amount of p-toluenesulfonic acid used is 3% of the mass of dimethylaminoethanol.

[0007] Furthermore, in step A3, the molar ratio of the tertiary amine group on the pretreatment stabilizer to bromoethane is 1:1, and the amount of potassium iodide used is 1.5% of the mass of bromoethane.

[0008] Furthermore, the modified polysiloxane is prepared by the following steps: Step B1: Mix dimethylaminoethanol, acrylic acid, p-toluenesulfonic acid and toluene evenly, and react for 3-5 hours at a speed of 200-300 r / min and a temperature of 110-115℃ to obtain the modifier. Mix 2,4,6-trimethylcyclotrisiloxane, the modifier, chloroplatinic acid and DMF evenly, and purge with nitrogen gas. React for 6-8 hours at a speed of 150-200 r / min and a temperature of 75-85℃ to obtain the modified monomer. Step B2: Mix lithium dimethylvinylsilane and tetrahydrofuran evenly, stir and add the modified monomer at 150-200 r / min and 0℃, heat to 25-30℃ and react for 7-9 h, then add dimethylchlorosilane and continue the reaction for 1-1.5 h to obtain pretreated polysiloxane. Mix the pretreated polysiloxane, mercaptoethanol, benzophenone and DMF evenly, and react for 5-10 min at 120-150 r / min, 20-25℃ and ultraviolet light irradiation to obtain functionalized polysiloxane. Step B3: Mix polyvinyl alcohol, epichlorohydrin, boron trifluoride ether, and DMF evenly. React at 120-150 r / min and 65-70℃ for 2-3 hours. Add hydroxide solution, raise the temperature to 75-80℃, and continue the reaction for 2-4 hours to obtain modified polyvinyl alcohol. Mix modified polyvinyl alcohol, functionalized polysiloxane, sodium hydroxide, and DMF evenly, purge with nitrogen for protection, and react at 150-200 r / min and 70-75℃ for 3-5 hours to obtain modified polysiloxane.

[0009] Furthermore, in step B1, the molar ratio of dimethylethanolamine to acrylic acid is 1:1, the amount of p-toluenesulfonic acid is 3% of the mass of acrylic acid, the molar ratio of 2,4,6-trimethylcyclotrisiloxane to the modifier is 1:3, and the amount of chloroplatinic acid is 1‰ of the mass of the modifier.

[0010] Furthermore, in step B2, the molar ratio of lithium dimethylvinylsilyl alcohol, modified monomer, and dimethylchlorosilane is 1:5:1, the molar ratio of pretreated polysiloxane and mercaptoethanol is 1:1, and the amount of benzophenone used is 2% of the mass of mercaptoethanol.

[0011] Furthermore, in step B3, the molar ratio of the hydroxyl groups on the polyvinyl alcohol to epichlorohydrin is 1:1, the amount of boron trifluoride ether is 5% of the mass of epichlorohydrin, the molar ratio of the epoxy groups on the modified polyvinyl alcohol to the hydroxyl groups on the functionalized polysiloxane is 1:1, and the amount of sodium hydroxide is 10% of the mass of the modified polyvinyl alcohol.

[0012] This invention relates to oil displacement technology, and its beneficial effects are as follows: The present invention provides an acid plugging agent for oilfields, comprising the following raw materials: hydrochloric acid, hydrofluoric acid, fluoroboric acid, a modified stabilizer, imidazoline, and water. The modified stabilizer is prepared by reacting the Si-H bonds on the modified stabilizer with the double bonds on the oleic acid to obtain a stabilizer monomer. The stabilizer monomer is then reacted with dimethylaminoethanol to esterify the carboxyl groups on the stabilizer monomer and the hydroxyl groups on the dimethylaminoethanol to obtain a pretreated stabilizer. The pretreated stabilizer is then reacted with bromoethane to form a quaternary ammonium salt structure between the tertiary amine on the pretreated stabilizer and the bromine on the bromoethane to obtain the modified stabilizer.

[0013] The modified stabilizer is prepared by esterifying the hydroxyl groups of dimethylaminoethanol and the carboxyl groups of acrylic acid using dimethylaminoethanol and acrylic acid as raw materials. The modifier is then reacted with 2,4,6-trimethylcyclotrisiloxane, causing the double bonds on the modifier to react with the Si-H bonds on 2,4,6-trimethylcyclotrisiloxane, thus preparing the modified monomer. Using lithium dimethylvinylsilanolate as an initiator and the modified monomer as a polymerization monomer, dimethylchlorosilane is added, causing the Si-Cl bonds on the dimethylchlorosilane to react with the lithium silanolate, thus preparing the pretreated polysiloxane. A pretreated polysiloxane is reacted with mercaptoethanol, causing the double bonds on the pretreated polysiloxane to react with the mercapto groups on the mercaptoethanol, thus obtaining a functionalized polysiloxane. Polyvinyl alcohol is reacted with epichlorohydrin, causing the hydroxyl groups on the polyvinyl alcohol to react with the epoxy groups on the epichlorohydrin. Then, under the action of sodium hydroxide solution, the ring is re-closed to form new epoxy groups, thus obtaining modified polyvinyl alcohol. Modified polyvinyl alcohol is reacted with functionalized polysiloxane, causing the epoxy groups on the modified polyvinyl alcohol to react with the hydroxyl groups on the functionalized polysiloxane, thus obtaining a modified polysiloxane.

[0014] The modified stabilizer contains a quaternary ammonium salt structure, which can combine with the negative charge on the clay to form a modified stabilizer coating on the clay surface. The polysiloxane molecular chains on the modified stabilizer form a hydrophobic film on the surface. Due to the incompatibility between water molecules and hydrophobic groups, the water-repelling groups are repelled. The outer alkyl long chains combine with the hydrophobic film formed by the polysiloxane molecules to form a second hydrophobic film, thus forming a bilayer film on the clay surface. Its hydrophobic effect is far superior to that of traditional monolayer films, effectively preventing external water from entering the interior of the clay particles and inhibiting the hydration and expansion of the clay. Detailed Implementation

[0015] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] Example 1: A method for preparing an acid plugging agent for oilfield use, specifically including the following steps: Step A1: Mix the modified polysiloxane, oleic acid, chloroplatinic acid and DMF evenly, purge with nitrogen, and react for 5 hours at a speed of 200 r / min and a temperature of 75℃ to obtain the stabilizer monomer. Step A2: Mix the stabilizer monomer, dimethylaminoethanol, p-toluenesulfonic acid and toluene evenly, and react for 3 hours at a speed of 200 r / min and a temperature of 110℃ to obtain the pretreated stabilizer. Step A3: Mix the pretreatment stabilizer, bromoethane, potassium iodide and DMF evenly, purge with nitrogen, and react for 20 h at a speed of 200 r / min and a temperature of 95 °C to obtain the modified stabilizer. Step A4: Weigh the following raw materials in parts by weight: 40 parts hydrochloric acid, 10 parts hydrofluoric acid, 5 parts fluoroboric acid, 1 part modified stabilizer, 0.1 parts imidazoline and 20 parts water. Mix the raw materials evenly to obtain an acid plugging agent for oil fields.

[0017] The molar ratio of Si-H bonds on the modified polysiloxane to oleic acid in step A1 is 1:1, and the amount of chloroplatinic acid used is 1‰ of the mass of oleic acid.

[0018] The molar ratio of the carboxyl group on the stabilizer monomer and dimethylaminoethanol in step A2 is 1:1, and the amount of p-toluenesulfonic acid used is 3% of the mass of dimethylaminoethanol.

[0019] The molar ratio of the tertiary amine group on the pretreatment stabilizer described in step A3 to bromoethane is 1:1, and the amount of potassium iodide used is 1.5% of the mass of bromoethane.

[0020] The hydrochloric acid in step A4 has a mass fraction of 28%, the hydrofluoric acid has a mass fraction of 4%, and the fluoroboric acid has a mass fraction of 10%.

[0021] The modified polysiloxane is prepared by the following steps: Step B1: Dimethylaminoethanol, acrylic acid, p-toluenesulfonic acid and toluene are mixed evenly and reacted for 3 hours at a speed of 200 r / min and a temperature of 110℃ to obtain the modifier. 2,4,6-trimethylcyclotrisiloxane, the modifier, chloroplatinic acid and DMF are mixed evenly and reacted under nitrogen protection at a speed of 150 r / min and a temperature of 75℃ for 6 hours to obtain the modified monomer. Step B2: Lithium dimethylvinylsilane and tetrahydrofuran were mixed evenly, and the modified monomer was added under the conditions of 150 r / min and 0℃. The temperature was raised to 25℃ and the reaction was carried out for 7 h. Then, dimethylchlorosilane was added and the reaction was continued for 1 h to obtain pretreated polysiloxane. The pretreated polysiloxane, mercaptoethanol, benzophenone and DMF were mixed evenly and the reaction was carried out for 5 min under the conditions of 120 r / min, 20℃ and ultraviolet light irradiation to obtain functionalized polysiloxane. Step B3: Polyvinyl alcohol, epichlorohydrin, boron trifluoride ether, and DMF are mixed evenly and reacted at 120 r / min and 65°C for 2 hours. Then, hydroxide solution is added, the temperature is raised to 75°C, and the reaction continues for 2 hours to obtain modified polyvinyl alcohol. Modified polyvinyl alcohol, functionalized polysiloxane, sodium hydroxide, and DMF are mixed evenly and protected with nitrogen gas. The reaction is carried out at 150 r / min and 70°C for 3 hours to obtain modified polysiloxane.

[0022] In step B1, the molar ratio of dimethylethanolamine to acrylic acid is 1:1, the amount of p-toluenesulfonic acid is 3% of the mass of acrylic acid, the molar ratio of 2,4,6-trimethylcyclotrisiloxane to the modifier is 1:3, and the amount of chloroplatinic acid is 1‰ of the mass of the modifier.

[0023] In step B2, the molar ratio of lithium dimethylvinylsilyl alcohol, modified monomer and dimethylchlorosilane is 1:5:1, the molar ratio of pretreated polysiloxane and mercaptoethanol is 1:1, and the amount of benzophenone used is 2% of the mass of mercaptoethanol.

[0024] In step B3, the molar ratio of hydroxyl groups on polyvinyl alcohol to epichlorohydrin is 1:1, the amount of boron trifluoride ether is 5% of the mass of epichlorohydrin, the molar ratio of epoxy groups on modified polyvinyl alcohol to hydroxyl groups on functionalized polysiloxane is 1:1, and the amount of sodium hydroxide is 10% of the mass of modified polyvinyl alcohol.

[0025] Example 2: A method for preparing an acid plugging agent for oilfield use, specifically including the following steps: Step A1: Mix the modified polysiloxane, oleic acid, chloroplatinic acid and DMF evenly, purge with nitrogen, and react for 6 hours at a speed of 200 r / min and a temperature of 80℃ to obtain the stabilizer monomer. Step A2: Mix the stabilizer monomer, dimethylaminoethanol, p-toluenesulfonic acid and toluene evenly, and react for 4 hours at a speed of 200 r / min and a temperature of 113℃ to obtain the pretreated stabilizer. Step A3: Mix the pretreatment stabilizer, bromoethane, potassium iodide and DMF evenly, purge with nitrogen, and react for 23 hours at a speed of 200 r / min and a temperature of 98℃ to obtain the modified stabilizer. Step A4: Weigh the following raw materials by weight: 50 parts hydrochloric acid, 15 parts hydrofluoric acid, 8 parts fluoroboric acid, 2 parts modified stabilizer, 0.3 parts imidazoline and 25 parts water. Mix the raw materials evenly to obtain an acid plugging agent for oil fields.

[0026] The molar ratio of Si-H bonds on the modified polysiloxane to oleic acid in step A1 is 1:1, and the amount of chloroplatinic acid used is 1‰ of the mass of oleic acid.

[0027] The molar ratio of the carboxyl group on the stabilizer monomer and dimethylaminoethanol in step A2 is 1:1, and the amount of p-toluenesulfonic acid used is 3% of the mass of dimethylaminoethanol.

[0028] The molar ratio of the tertiary amine group on the pretreatment stabilizer described in step A3 to bromoethane is 1:1, and the amount of potassium iodide used is 1.5% of the mass of bromoethane.

[0029] The hydrochloric acid in step A4 has a mass fraction of 28%, the hydrofluoric acid has a mass fraction of 4%, and the fluoroboric acid has a mass fraction of 10%.

[0030] The modified polysiloxane is prepared by the following steps: Step B1: Dimethylaminoethanol, acrylic acid, p-toluenesulfonic acid and toluene are mixed evenly and reacted at 200 r / min and 113℃ for 4 h to obtain the modifier. 2,4,6-trimethylcyclotrisiloxane, the modifier, chloroplatinic acid and DMF are mixed evenly and purged with nitrogen. The mixture is reacted at 150 r / min and 80℃ for 7 h to obtain the modified monomer. Step B2: Lithium dimethylvinylsilane and tetrahydrofuran were mixed evenly. The mixture was stirred and modified monomers were added at 150 r / min and 0°C. The mixture was heated to 28°C and reacted for 8 h. Then, dimethylchlorosilane was added and the reaction was continued for 1.5 h to obtain pretreated polysiloxane. The pretreated polysiloxane, mercaptoethanol, benzophenone and DMF were mixed evenly and reacted for 8 min at 120 r / min, 25°C and under ultraviolet light irradiation to obtain functionalized polysiloxane. Step B3: Polyvinyl alcohol, epichlorohydrin, boron trifluoride ether, and DMF are mixed evenly and reacted at 120 r / min and 68°C for 3 hours. Then, hydroxide solution is added, the temperature is raised to 78°C, and the reaction continues for 3 hours to obtain modified polyvinyl alcohol. Modified polyvinyl alcohol, functionalized polysiloxane, sodium hydroxide, and DMF are mixed evenly and protected with nitrogen gas. The reaction is carried out at 150 r / min and 75°C for 4 hours to obtain modified polysiloxane.

[0031] In step B1, the molar ratio of dimethylethanolamine to acrylic acid is 1:1, the amount of p-toluenesulfonic acid is 3% of the mass of acrylic acid, the molar ratio of 2,4,6-trimethylcyclotrisiloxane to the modifier is 1:3, and the amount of chloroplatinic acid is 1‰ of the mass of the modifier.

[0032] In step B2, the molar ratio of lithium dimethylvinylsilyl alcohol, modified monomer and dimethylchlorosilane is 1:5:1, the molar ratio of pretreated polysiloxane and mercaptoethanol is 1:1, and the amount of benzophenone used is 2% of the mass of mercaptoethanol.

[0033] In step B3, the molar ratio of hydroxyl groups on polyvinyl alcohol to epichlorohydrin is 1:1, the amount of boron trifluoride ether is 5% of the mass of epichlorohydrin, the molar ratio of epoxy groups on modified polyvinyl alcohol to hydroxyl groups on functionalized polysiloxane is 1:1, and the amount of sodium hydroxide is 10% of the mass of modified polyvinyl alcohol.

[0034] Example 3: A method for preparing an acid plugging agent for oilfield use, specifically including the following steps: Step A1: Mix the modified polysiloxane, oleic acid, chloroplatinic acid and DMF evenly, purge with nitrogen, and react for 7 hours at a speed of 300 r / min and a temperature of 85℃ to obtain the stabilizer monomer. Step A2: Mix the stabilizer monomer, dimethylaminoethanol, p-toluenesulfonic acid and toluene evenly, and react for 5 hours at a speed of 300 r / min and a temperature of 115℃ to obtain the pretreated stabilizer. Step A3: Mix the pretreatment stabilizer, bromoethane, potassium iodide and DMF evenly, purge with nitrogen, and react for 25 h at a speed of 300 r / min and a temperature of 100℃ to obtain the modified stabilizer. Step A4: Weigh the following raw materials in parts by weight: 60 parts hydrochloric acid, 20 parts hydrofluoric acid, 10 parts fluoroboric acid, 3 parts modified stabilizer, 0.5 parts imidazoline, and 30 parts water. Mix the raw materials evenly to obtain an acid plugging agent for oil fields.

[0035] The molar ratio of Si-H bonds on the modified polysiloxane to oleic acid in step A1 is 1:1, and the amount of chloroplatinic acid used is 1‰ of the mass of oleic acid.

[0036] The molar ratio of the carboxyl group on the stabilizer monomer and dimethylaminoethanol in step A2 is 1:1, and the amount of p-toluenesulfonic acid used is 3% of the mass of dimethylaminoethanol.

[0037] The molar ratio of the tertiary amine group on the pretreatment stabilizer described in step A3 to bromoethane is 1:1, and the amount of potassium iodide used is 1.5% of the mass of bromoethane.

[0038] The hydrochloric acid in step A4 has a mass fraction of 28%, the hydrofluoric acid has a mass fraction of 4%, and the fluoroboric acid has a mass fraction of 10%.

[0039] The modified polysiloxane is prepared by the following steps: Step B1: Dimethylaminoethanol, acrylic acid, p-toluenesulfonic acid and toluene are mixed evenly and reacted at 300 r / min and 115℃ for 5 h to obtain the modifier. 2,4,6-trimethylcyclotrisiloxane, the modifier, chloroplatinic acid and DMF are mixed evenly and purged with nitrogen. The mixture is reacted at 200 r / min and 85℃ for 8 h to obtain the modified monomer. Step B2: Lithium dimethylvinylsilane and tetrahydrofuran were mixed evenly. The mixture was stirred and modified monomers were added at 200 r / min and 0°C. The temperature was raised to 30°C and the reaction was carried out for 9 h. Then, dimethylchlorosilane was added and the reaction was continued for 1.5 h to obtain pretreated polysiloxane. The pretreated polysiloxane, mercaptoethanol, benzophenone and DMF were mixed evenly and the mixture was reacted for 10 min at 150 r / min, 25°C and under ultraviolet light irradiation to obtain functionalized polysiloxane. Step B3: Polyvinyl alcohol, epichlorohydrin, boron trifluoride ether, and DMF are mixed evenly and reacted at 150 r / min and 70°C for 3 hours. Then, hydroxide solution is added, the temperature is raised to 80°C, and the reaction continues for 4 hours to obtain modified polyvinyl alcohol. Modified polyvinyl alcohol, functionalized polysiloxane, sodium hydroxide, and DMF are mixed evenly and nitrogen gas is introduced for protection. The reaction is carried out at 200 r / min and 75°C for 5 hours to obtain modified polysiloxane.

[0040] In step B1, the molar ratio of dimethylethanolamine to acrylic acid is 1:1, the amount of p-toluenesulfonic acid is 3% of the mass of acrylic acid, the molar ratio of 2,4,6-trimethylcyclotrisiloxane to the modifier is 1:3, and the amount of chloroplatinic acid is 1‰ of the mass of the modifier.

[0041] In step B2, the molar ratio of lithium dimethylvinylsilyl alcohol, modified monomer and dimethylchlorosilane is 1:5:1, the molar ratio of pretreated polysiloxane and mercaptoethanol is 1:1, and the amount of benzophenone used is 2% of the mass of mercaptoethanol.

[0042] In step B3, the molar ratio of hydroxyl groups on polyvinyl alcohol to epichlorohydrin is 1:1, the amount of boron trifluoride ether is 5% of the mass of epichlorohydrin, the molar ratio of epoxy groups on modified polyvinyl alcohol to hydroxyl groups on functionalized polysiloxane is 1:1, and the amount of sodium hydroxide is 10% of the mass of modified polyvinyl alcohol.

[0043] Comparative Example 1: This comparative example uses a stabilizer monomer instead of a modified stabilizer, while the other steps are the same as in Example 1.

[0044] Comparative Example 2: This comparative example uses functionalized polysiloxane instead of the pretreatment stabilizer, while the remaining steps are the same as in Example 1.

[0045] Comparative Example 3: This comparative example uses acrylic acid instead of oleic acid, but the other steps are the same as in Example 1.

[0046] The anti-swelling rate of the acid-resistant unblocking agents prepared in Examples 1-3 and Comparative Examples 1-3 was tested according to the centrifugation method in SY / T5971-94. 0.5g of bentonite was weighed and added to 10mL of the unblocking agent. After standing at room temperature for 2 hours, the mixture was centrifuged at 1500r / min for 15 minutes, and the volume after expansion was recorded. Then, distilled water and kerosene were used instead of the unblocking agent, and the expansion volume of bentonite in distilled water and kerosene was recorded respectively. The anti-swelling rate was calculated. 0.5g of bentonite was weighed and added to 10mL of the unblocking agent. After standing at room temperature for 2 hours, the mixture was centrifuged at 1500r / min for 15 minutes, and the volume after expansion was recorded. The supernatant was removed, distilled water was added, and the mixture was stood at room temperature for 2 hours. After centrifugation at 1500r / min for 15 minutes, this process was repeated twice, and the expansion volume was recorded. The water wash resistance rate was calculated. The test results are shown in Table 1 below.

[0047] Table 1

[0048] As shown in Table 1, this application has a very good anti-swelling effect.

[0049] The above description is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined in the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing an acid plugging agent for oilfield use, characterized in that: Specifically, the steps include the following: Step A1: Mix the modified polysiloxane, oleic acid, chloroplatinic acid and DMF evenly, purge with nitrogen gas, and react to obtain the stabilizer monomer. Step A2: Mix and react the stabilizer monomer, dimethylaminoethanol, p-toluenesulfonic acid and toluene to prepare the pretreated stabilizer; Step A3: Mix the pretreatment stabilizer, bromoethane, potassium iodide and DMF evenly, purge with nitrogen gas for protection, and carry out the reaction to obtain the modified stabilizer; Step A4: Weigh the following raw materials in parts by weight: 40-60 parts hydrochloric acid, 10-20 parts hydrofluoric acid, 5-10 parts fluoroboric acid, 1-3 parts modified stabilizer, 0.1-0.5 parts imidazoline, and 20-30 parts water. Mix the raw materials evenly to obtain an acid plugging agent for oil fields.

2. The preparation method of the oilfield acid plugging agent according to claim 1, characterized in that: The molar ratio of Si-H bonds and oleic acid on the modified polysiloxane described in step A1 is 1:

1.

3. The preparation method of the oilfield acid plugging agent according to claim 1, characterized in that: The molar ratio of the carboxyl group on the stabilizer monomer and dimethylaminoethanol in step A2 is 1:

1.

4. The preparation method of the oilfield acid plugging agent according to claim 1, characterized in that: The molar ratio of tertiary amine groups and bromoethane on the pretreatment stabilizer described in step A3 is 1:

1.

5. The preparation method of the oilfield acid plugging agent according to claim 1, characterized in that: The modified polysiloxane is prepared by the following steps: Step B1: Mix dimethylaminoethanol, acrylic acid, p-toluenesulfonic acid and toluene to prepare a modifier. Mix 2,4,6-trimethylcyclotrisiloxane, the modifier, chloroplatinic acid and DMF evenly, and carry out the reaction under nitrogen protection to prepare a modified monomer. Step B2: Lithium dimethylvinylsilane and tetrahydrofuran are mixed and stirred, and the modified monomer is added. After heating and reacting, dimethylchlorosilane is added and the reaction is continued to obtain pretreated polysiloxane. The pretreated polysiloxane, mercaptoethanol, benzophenone and DMF are mixed and reacted with ultraviolet light to obtain functionalized polysiloxane. Step B3: After mixing and reacting polyvinyl alcohol, epichlorohydrin, boron trifluoride ether and DMF, add hydroxide solution and heat to react to obtain modified polyvinyl alcohol. Mix the modified polyvinyl alcohol, functionalized polysiloxane, sodium hydroxide and DMF evenly, purge with nitrogen gas for protection, and react to obtain modified polysiloxane.

6. The method for preparing the oilfield acid plugging agent according to claim 5, characterized in that: The molar ratio of dimethylethanolamine and acrylic acid in step B1 is 1:1, and the molar ratio of 2,4,6-trimethylcyclotrisiloxane and the modifier is 1:

3.

7. The method for preparing the oilfield acid plugging agent according to claim 5, characterized in that: In step B2, the molar ratio of lithium dimethylvinylsilyl alcohol, modified monomer, and dimethylchlorosilane is 1:5:1, and the molar ratio of pretreated polysiloxane and mercaptoethanol is 1:

1.

8. The method for preparing the oilfield acid plugging agent according to claim 5, characterized in that: In step B3, the molar ratio of hydroxyl groups on polyvinyl alcohol to epichlorohydrin is 1:1, and the molar ratio of epoxy groups on modified polyvinyl alcohol to hydroxyl groups on functionalized polysiloxane is 1:

1.

9. An acid plugging agent for oilfield use, characterized in that: Prepared according to any one of the preparation methods described in claims 1-8.

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