A phosphonic acid group-containing polymer viscosity reducer, a preparation method and application thereof

Abstract

This invention provides a phosphonic acid-based polymer viscosity reducer, its preparation method, and its application. The raw materials for preparation include the following components: a carboxylic acid-based monomer, a sulfonic acid-based monomer, a diisopropylaminophosphonic acid monomer, a nonionic monomer, a molecular weight regulator, and an initiator. The viscosity reducer prepared by this invention, in the presence of the above-mentioned raw materials, possesses both phosphonic acid and sulfonic acid groups, and maintains good viscosity-reducing effects even under high temperature and salt / calcium contamination conditions, especially exhibiting good anti-calcium effects.

Description

Technical Field

[0001] This invention belongs to the field of viscosity reducer technology, and particularly relates to a phosphonic acid-based polymer viscosity reducer, its preparation method, and its application. Background Technology

[0002] With the continuous increase in energy resource consumption and the continuous improvement of oil and gas exploration and development technologies, oil drilling is gradually shifting towards deeper formations. During the drilling process, the accumulation of low-density solids leads to an increase in drilling fluid density; moreover, the bottom-hole temperature of deep wells increases, causing phenomena such as high-temperature dispersion and high-temperature aggregation of drilling fluid substrates. At the same time, the drilling fluid is contaminated by salt, calcium, and acid ions, resulting in a decrease in the rheological properties of the drilling fluid and seriously affecting its downhole performance.

[0003] Currently, commonly used viscosity reducers are either naturally modified or synthetic polymers. Naturally modified viscosity reducers mainly include modified lignin, modified humic acid, and modified tannin, which are abundant and inexpensive, but their effectiveness decreases significantly with repeated use. Synthetic polymer viscosity reducers, with sulfonic acid and carboxylic acid groups as the main temperature and salt resistance functional groups, possess good temperature and salt resistance capabilities, but still cannot fully meet the needs of practical applications in deep formations with high temperatures and salt / calcium contamination. Therefore, to address the shortcomings of existing viscosity reducers, it is crucial to develop a high-performance viscosity reducer that can meet the functional requirements of traditional drilling fluids while also meeting the requirements of drilling in deeper and more complex formations. This is of great significance for the exploration and development of high-temperature deep wells. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a phosphonic acid-based polymer viscosity reducer, its preparation method and application, which has a good viscosity reducing effect, strong anti-fouling ability, and meets the exploration and development needs of high temperature deep wells.

[0005] This invention provides a phosphonic acid-based polymer viscosity reducer, the raw materials of which include the following components:

[0006] Monomers containing carboxylic acid groups, monomers containing sulfonic acid groups, diisopropylaminophosphonic acid monomers, nonionic monomers, molecular weight regulators, and initiators.

[0007] Preferably, the molar ratio of the carboxylic acid-containing monomer, the sulfonic acid-containing monomer, the diisopropylaminophosphonic acid monomer, and the nonionic monomer is (0.8-0.5):(0.2-0.1):(0.25-0.1):(0.2-0.05).

[0008] Preferably, the carboxylic acid-containing monomer is selected from one or more of acrylic acid, methacrylic acid, and itaconic acid;

[0009] The sulfonic acid-containing monomer is selected from one or more of 2-acrylamido-2-methylpropanesulfonic acid, 2-acryloyloxy-2-methylpropanesulfonic acid, and acryloyloxybutylsulfonic acid;

[0010] The nonionic monomer is selected from one or more of N,N-dimethylacrylamide, N,N-diethylacrylamide, N-isobutylacrylamide, and N-vinylpyrrolidone.

[0011] Preferably, the total mass of the carboxylic acid monomer, the sulfonic acid monomer, the diisopropylaminophosphonic acid monomer, and the nonionic monomer accounts for 20-50% of the raw materials.

[0012] Preferably, the molecular weight regulator is selected from one or more of p-methoxyphenol, methylstyrene dimer, tert-dodecyl mercaptan, and copper sulfate;

[0013] The molecular weight regulator accounts for 0.3 to 4% of the total mass of the four monomers.

[0014] Preferably, the initiator is selected from sodium persulfate and / or sodium perbromate;

[0015] The initiator accounts for 0.5% to 5% of the total mass of the four monomers.

[0016] This invention provides a method for preparing the phosphonic acid-containing polymer viscosity reducer described in the above-mentioned technical solution, comprising the following steps:

[0017] A phosphonic acid-containing polymer viscosity reducer is obtained by mixing a carboxylic acid monomer, a sulfonic acid monomer, a diisopropylaminophosphonic acid monomer, a nonionic monomer, a molecular weight regulator, and water evenly, adding an initiator, and then performing a polymerization reaction.

[0018] Preferably, the polymerization temperature is 60–100°C and the polymerization time is 2–5 hours.

[0019] Preferably, after the polymerization reaction is completed, the pH value of the reaction product is neutralized to 8-9 to obtain a viscous product, which is then dried and pulverized to obtain a phosphonic acid-based polymer viscosity reducer.

[0020] This invention provides an application of a phosphonic acid-based polymer viscosity reducer in calcium chloride-based slurry.

[0021] This invention provides a phosphonic acid-based polymer viscosity reducer, prepared from the following raw materials: a carboxylic acid-based monomer, a sulfonic acid-based monomer, a diisopropylaminophosphonic acid monomer, a nonionic monomer, a molecular weight regulator, and an initiator. The viscosity reducer prepared in the presence of the above-mentioned raw materials possesses both phosphonic acid and sulfonic acid groups, and maintains good viscosity-reducing effects even under high temperature and salt / calcium contamination conditions, especially exhibiting good anti-calcium effects. Detailed Implementation

[0022] This invention provides a phosphonic acid-based polymer viscosity reducer, the raw materials of which include the following components:

[0023] Monomers containing carboxylic acid groups, monomers containing sulfonic acid groups, diisopropylaminophosphonic acid monomers, nonionic monomers, molecular weight regulators, and initiators.

[0024] In this invention, the molar ratio of the carboxylic acid-containing monomer, the sulfonic acid-containing monomer, the diisopropylaminophosphonic acid monomer, and the nonionic monomer is (0.8-0.5):(0.2-0.1):(0.25-0.1):(0.2-0.05); in a specific embodiment, the molar ratio of the carboxylic acid-containing monomer, the sulfonic acid-containing monomer, the diisopropylaminophosphonic acid monomer, and the nonionic monomer is more preferably (0.75-0.6):(0.15-0.1):(0.2-0.1):(0.15-0.05).

[0025] The carboxylic acid-containing monomers described in this invention are selected from one or more of acrylic acid, methacrylic acid, and itaconic acid;

[0026] The sulfonic acid-containing monomer is selected from one or more of 2-acrylamido-2-methylpropanesulfonic acid, 2-acryloyloxy-2-methylpropanesulfonic acid, and acryloyloxybutylsulfonic acid;

[0027] The nonionic monomer is selected from one or more of N,N-dimethylacrylamide, N,N-diethylacrylamide, N-isobutylacrylamide, and N-vinylpyrrolidone.

[0028] The diisopropylaminophosphonic acid monomer described in this invention is the monomer disclosed in TWI836683B (polymerizable phosphonic acids (salts) and their preparation methods and copolymers and drilling fluids).

[0029] In this invention, the total mass of the carboxylic acid-containing monomer, the sulfonic acid-containing monomer, the diisopropylaminophosphonic acid monomer, and the nonionic monomer accounts for 20-50% of the raw materials used in preparation. The specific percentages are 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, or 50%.

[0030] This invention employs the above-mentioned sulfonic acid monomers and diisopropylaminophosphonic acid monomers to give the viscosity reducer both phosphonic acid and sulfonic acid groups. Under conditions of high temperature and salt and calcium contamination, it still has a good viscosity reducing effect, especially a good anti-calcium effect.

[0031] Preferably, the molecular weight regulator is selected from one or more of p-methoxyphenol, methylstyrene dimer, tert-dodecyl mercaptan, and copper sulfate; the molecular weight regulator accounts for 0.3-4% of the total mass of the four monomers (monomers containing carboxylic acid groups, monomers containing sulfonic acid groups, diisopropylaminophosphonic acid monomers, and nonionic monomers), specifically in the following proportions: 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, and 1.0%. 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 0.7%, 3.8%, 3.9%, or 4.0%.

[0032] In this invention, the initiator is selected from sodium persulfate and / or sodium perbromate; the initiator accounts for 0.5% to 5% of the total mass of the four monomers, specifically in the following proportions: 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, and 2.2%. 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4.0%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9%, or 5.0%.

[0033] This invention provides a method for preparing the phosphonic acid-containing polymer viscosity reducer described in the above-mentioned technical solution, comprising the following steps:

[0034] A phosphonic acid-containing polymer viscosity reducer is obtained by mixing a carboxylic acid monomer, a sulfonic acid monomer, a diisopropylaminophosphonic acid monomer, a nonionic monomer, a molecular weight regulator, and water evenly, adding an initiator, and then performing a polymerization reaction.

[0035] In this invention, the polymerization temperature is 60-100°C, specifically 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, or 100°C; the polymerization time is 2-5 hours, specifically 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, or 5 hours.

[0036] Preferably, after the polymerization reaction is completed, the pH value of the reaction product is neutralized to 8-9 to obtain a viscous product, which is then dried and pulverized to obtain a phosphonic acid-based polymer viscosity reducer.

[0037] The present invention preferably uses sodium hydroxide to neutralize the reaction product; the pH value is 8 or 9.

[0038] In this invention, the monomer content of the phosphonic acid-based polymer viscosity reducer is 20-50%. The monomer content refers to the total content of carboxylic acid-based monomers, sulfonic acid-based monomers, diisopropylaminophosphonic acid monomers, and nonionic monomers; the specific content is 20%, 30%, or 50%.

[0039] The present invention also provides the application of a phosphonic acid-based polymer viscosity reducer in calcium chloride-based slurry.

[0040] In this invention, the calcium chloride-based slurry is prepared by the following method:

[0041] Add 1.12g of anhydrous sodium carbonate and 32g of calcium bentonite to 400mL of water, stir at high speed for 20min, and cure at room temperature for 24h. Then add 1.2g of calcium chloride, stir at high speed for 20min, and cure at room temperature for 24h to obtain calcium chloride-based slurry.

[0042] In this invention, the viscosity reducer sample described in the above technical solution is added to the base slurry, stirred at high speed for 20 minutes, aged by rolling at 180°C for 16 hours, and then stirred at high speed for 5 minutes at room temperature. The rheological parameters of the drilling fluid are measured sequentially using a six-speed rotational viscometer, and the viscosity reduction rate of the viscosity reducer is calculated. The viscosity reducer accounts for 0.4 wt% of the base slurry mass.

[0043] To further illustrate the present invention, the following detailed description, in conjunction with embodiments, provides a phosphonic acid-based polymer viscosity reducer, its preparation method, and its application. However, these descriptions should not be construed as limiting the scope of protection of the present invention.

[0044] Example 1

[0045] 16.5g acrylic acid, 13.7g 2-acrylamido-2-methylpropanesulfonic acid, 14.4g diisopropylaminophosphonic acid, 5.4g N,N-dimethylacrylamide, and 0.5g p-methoxyphenol were dissolved in 50g of water and added to a reaction vessel. The temperature was raised to 60℃~85℃. Then, 1.0g sodium persulfate was dissolved in water and added to the reaction vessel. The reaction was carried out at a constant temperature for 4 hours to obtain a product with a monomer content of 50%. After the reaction was completed, the pH value was neutralized to 8 with sodium hydroxide. After drying and pulverizing, a phosphonic acid-based polymer viscosity reducer was obtained.

[0046] Example 2:

[0047] 14.8g acrylic acid, 5.0g itaconic acid, 15.1g 2-acrylamido-2-methylpropanesulfonic acid, 8.7g diisopropylaminophosphonic acid, 6.4g N-isobutylacrylamide, and 1.5g methylstyrene dimer were dissolved in 50g of water and added to a reaction vessel. The temperature was raised to 65℃~90℃. Then, 1.0g sodium perbromate was dissolved in water and added to the reaction vessel. The reaction was carried out at a constant temperature for 5 hours to obtain a product with a monomer content of 50%. After the reaction was completed, the pH value was neutralized to 8 with sodium hydroxide. After drying and pulverizing, a phosphonic acid-based polymer viscosity reducer was obtained.

[0048] Example 3:

[0049] 8.7g methacrylic acid, 2.7g itaconic acid, 9.3g 2-acryloyloxy-2-methylpropanesulfonic acid, 5.5g diisopropylaminophosphonic acid, 3.8g N-vinylpyrrolidone, and 0.6g tert-dodecyl mercaptan were dissolved in 70g of water and added to a reaction vessel. The temperature was raised to 60℃~90℃. Then, 0.9g sodium perbromate was dissolved in water and added to the reaction vessel. The reaction was carried out at a constant temperature for 3 hours to obtain a product with a monomer content of 30%. After the reaction was completed, the pH value was neutralized to 8 with sodium hydroxide. After drying and pulverizing, a phosphonic acid-based polymer viscosity reducer was obtained.

[0050] Example 4:

[0051] 10.8g of methacrylic acid, 10.2g of 2-acryloyloxy-2-methylpropanesulfonic acid, 5.8g of diisopropylaminophosphonic acid, 3.2g of N,N-diethylacrylamide, and 0.45g of copper sulfate were dissolved in 70g of water and added to a reaction vessel. The temperature was raised to 65℃~90℃. Then, 0.9g of sodium persulfate was dissolved in water and added to the reaction vessel. The reaction was carried out at a constant temperature for 3 hours to obtain a product with a monomer content of 30%. After the reaction was completed, the pH value was neutralized to 8 with sodium hydroxide. After drying and pulverizing, a phosphonic acid-based polymer viscosity reducer was obtained.

[0052] Example 5:

[0053] 7.1g of methacrylic acid, 6.2g of acryloyloxybutylsulfonic acid, 3.9g of diisopropylaminophosphonic acid, 2.8g of N-vinylpyrrolidone, and 0.6g of tert-dodecyl mercaptan were dissolved in 70g of water and added to a reaction vessel. The temperature was raised to 60℃~85℃. Then, 0.8g of sodium persulfate was dissolved in water and added to the reaction vessel. The reaction was carried out at a constant temperature for 4 hours to obtain a product with a monomer content of 20%. After the reaction was completed, the pH value was neutralized to 8 with sodium hydroxide. After drying and pulverizing, a phosphonic acid-based polymer viscosity reducer was obtained.

[0054] Example 6:

[0055] 6.5g acrylic acid, 3.4g 2-acryloyloxy-2-methylpropanesulfonic acid, 6.8g diisopropylaminophosphonic acid, 3.3g N,N-dimethylacrylamide, and 0.6g methylstyrene dimer were dissolved in 70g of water and added to a reaction vessel. The temperature was raised to 65℃~90℃. Then, 0.8g sodium perbromate was dissolved in water and added to the reaction vessel. The reaction was carried out at a constant temperature for 3 hours to obtain a product with a monomer content of 20%. After the reaction was completed, the pH value was neutralized to 8 with sodium hydroxide. After drying and pulverizing, a phosphonic acid-based polymer viscosity reducer was obtained.

[0056] Comparative Example 1:

[0057] 10.7g acrylic acid, 3.2g itaconic acid, 10.3g 2-acryloyloxy-2-methylpropanesulfonic acid, 5.8g 2-acrylamido-2-methylpropionic acid, and 0.6g thioacetic acid were dissolved in 70g of water and added to a reaction vessel. The temperature was raised to 60℃. Then, 0.9g potassium persulfate was dissolved in water and added to the reaction vessel. The temperature of the reaction vessel was raised to 75℃ and reacted for 3 hours to obtain a product with a monomer content of 30%. After the reaction was completed, the pH value was neutralized to 8 with sodium hydroxide. After drying and pulverizing, a phosphonic acid-based polymer viscosity reducer was obtained.

[0058] Comparative Example 2

[0059] 9.0g of acrylic acid, 2.7g of 2-acryloyloxy-2-methylpropanesulfonic acid, 23.3g of 2-acrylamido-2-methylpropionic acid, and 0.53g of mercaptoacetic acid were dissolved in 65g of water and added to a reaction vessel. The temperature was raised to 60℃. Then, 1.05g of potassium persulfate was dissolved in water and added to the reaction vessel. The temperature of the reaction vessel was raised to 75℃ and reacted for 3 hours to obtain a product with a monomer content of 35%. After the reaction was completed, the pH value was neutralized to 8 with sodium hydroxide. After drying and pulverizing, a phosphonic acid-based polymer viscosity reducer was obtained.

[0060] The performance of the phosphonic acid-based polymer viscosity reducers obtained in Examples 1-6 and the comparative examples of the present invention was evaluated.

[0061] (1) Preparation of base slurry

[0062] Calcium chloride-based slurry: Add 1.12g of anhydrous sodium carbonate and 32g of calcium bentonite to 400mL of water, stir at high speed for 20min, and cure at room temperature for 24h. Then add 1.2g of calcium chloride, stir at high speed for 20min, and cure at room temperature for 24h to obtain calcium chloride-based slurry.

[0063] (2) Performance evaluation of viscosity reducers

[0064] The viscosity reducer samples obtained in Examples 1 to 6 were added to the base slurry, stirred at high speed for 20 minutes, aged at 180°C for 16 hours, and then stirred at high speed for 5 minutes at room temperature. The rheological parameters of the drilling fluid were measured sequentially using a six-speed rotational viscometer, and the viscosity reduction rate of the viscosity reducer was calculated.

[0065]

[0066] (φ100)0 is the reading of the base slurry at a speed of 100 r / min on a six-speed rotational viscometer; (φ100)1 is the reading of the base slurry at a speed of 100 r / min on a six-speed rotational viscometer after adding the viscosity reducer.

[0067] Table 1. Evaluation of the viscosity-reducing performance of the viscosity-reducing agents prepared in Examples 1-6 and Comparative Examples 1-2.

[0068]

[0069] As can be seen from the test results in Table 1, the phosphonic acid-based polymer viscosity reducer of the present invention exhibits good viscosity-reducing effects in calcium chloride-based slurry. Under the same conditions, the comparative examples show significant differences in performance in calcium chloride-based slurry, all of which are lower than those of the phosphonic acid-based polymer viscosity reducer of the present invention. This indicates that the phosphonic acid-based polymer viscosity reducer of the present invention has better calcium resistance.

[0070] As can be seen from the above embodiments, the present invention provides a phosphonic acid-based polymer viscosity reducer. The raw materials for preparation include the following components: a carboxylic acid-based monomer, a sulfonic acid-based monomer, a diisopropylaminophosphonic acid monomer, a nonionic monomer, a molecular weight regulator, and an initiator. The viscosity reducer prepared by the present invention, in the presence of the above-mentioned raw materials, possesses both phosphonic acid and sulfonic acid groups, and still exhibits good viscosity-reducing effects under high temperature and salt / calcium contamination conditions, especially demonstrating good anti-calcium effects. Experimental results show that when the viscosity reducer is added at a concentration of 0.4 wt%, the viscosity reduction rate in calcium chloride-based slurry is 80.36%–85.36%.

[0071] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A phosphonic acid-based polymer viscosity reducer, the raw materials for which are prepared include the following components: Monomers containing carboxylic acid groups, monomers containing sulfonic acid groups, diisopropylaminophosphonic acid monomers, nonionic monomers, molecular weight regulators, and initiators.

2. The phosphonic acid-containing polymer viscosity reducer according to claim 1, characterized in that, The molar ratio of the carboxylic acid-containing monomer, the sulfonic acid-containing monomer, the diisopropylaminophosphonic acid monomer, and the nonionic monomer is (0.8-0.5):(0.2-0.1):(0.25-0.1):(0.2-0.05).

3. The phosphonic acid-containing polymer viscosity reducer according to claim 1, characterized in that, The carboxylic acid-containing monomer is selected from one or more of acrylic acid, methacrylic acid and itaconic acid; The sulfonic acid-containing monomer is selected from one or more of 2-acrylamido-2-methylpropanesulfonic acid, 2-acryloyloxy-2-methylpropanesulfonic acid, and acryloyloxybutylsulfonic acid; The nonionic monomer is selected from one or more of N,N-dimethylacrylamide, N,N-diethylacrylamide, N-isobutylacrylamide, and N-vinylpyrrolidone.

4. The phosphonic acid-containing polymer viscosity reducer according to claim 1, characterized in that, The total mass of the carboxylic acid monomer, sulfonic acid monomer, diisopropylaminophosphonic acid monomer and nonionic monomer accounts for 20-50% of the raw materials.

5. The phosphonic acid-based polymer viscosity reducer according to claim 1, characterized in that, The molecular weight regulator is selected from one or more of p-methoxyphenol, methylstyrene dimer, tert-dodecyl mercaptan and copper sulfate; The molecular weight regulator accounts for 0.3 to 4% of the total mass of the four monomers.

6. The phosphonic acid-based polymer viscosity reducer according to claim 1, characterized in that, The initiator is selected from sodium persulfate and / or sodium perbromate; The initiator accounts for 0.5% to 5% of the total mass of the four monomers.

7. A method for preparing a phosphonic acid-containing polymer viscosity reducer according to any one of claims 1 to 6, comprising the following steps: A phosphonic acid-containing polymer viscosity reducer is obtained by mixing a carboxylic acid monomer, a sulfonic acid monomer, a diisopropylaminophosphonic acid monomer, a nonionic monomer, a molecular weight regulator, and water evenly, adding an initiator, and then performing a polymerization reaction.

8. The preparation method according to claim 7, characterized in that, The polymerization reaction temperature is 60–100℃, and the polymerization reaction time is 2–5 hours.

9. The preparation method according to claim 7, characterized in that, After the polymerization reaction is completed, the pH value of the reaction product is neutralized to 8-9 to obtain a viscous product, which is then dried and pulverized to obtain a phosphonic acid-based polymer viscosity reducer.

10. Application of a phosphonic acid-based polymer viscosity reducer in calcium chloride-based slurry.

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