A tackifying fluid loss additive, its preparation method and drilling fluid

Abstract

The application provides a tackifying fluid loss additive, a preparation method thereof and a drilling fluid, and belongs to the technical field of synthesis of treatment agents for oilfield drilling fluids. Raw materials N-vinylpyrrolidone, 2-acrylamide-2-methylpropanesulfonic acid and allyl glycerol ether are dissolved in water to form an aqueous solution in a mass ratio of (1-3):(5-7):(1-4), the pH value of the aqueous solution is adjusted, a crosslinking agent and an initiator are added, and a tackifying fluid loss additive is obtained through crosslinking copolymerization. The tackifying fluid loss additive for the drilling fluid obtained by the application has a temperature resistance of up to 200 DEG C, good effects of tackifying, improving shear force and reducing fluid loss, and can be widely applied to high-temperature solid-free drilling fluid systems and other various water-based drilling fluid systems, and has a wide application prospect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of drilling fluid treatment agent synthesis for oil field, and particularly relates to a viscosity increasing and filtration reducing agent, a preparation method thereof and a drilling fluid. BACKGROUND

[0002] In recent years, with the continuous deepening of exploration and development, high-temperature and deep wells gradually increase, and more requirements are put forward for the performance of drilling fluid treatment agents. Under high temperature (>180℃) and high salinity, the existing drilling fluid viscosity increasing agent cannot make the drilling fluid system maintain good rheological properties, and can only increase the dosage and continuously supplement the treatment agent to make the drilling fluid maintain good rheological properties and filtration properties as much as possible. Therefore, the research and development of a drilling fluid viscosity increasing and filtration reducing agent with stable performance under high temperature and high salinity is particularly important.

[0003] In terms of temperature-resistant and salt-resistant viscosity increasing agents, relevant technical personnel at home and abroad have actively explored. Chinese patent CN107759729A discloses a temperature-resistant and salt-resistant drilling fluid viscosity increasing agent. The viscosity increasing agent is synthesized by using N-vinyl pyrrolidone, 4-vinyl-1-(3-sulfopropyl) pyridine inner salt and acrylamide as reaction monomers. The synthesized viscosity increasing agent can resist 3% calcium chloride and 3% magnesium chloride, and can resist temperature up to 180℃. However, the dosage of the viscosity increasing agent is large, which increases the drilling cost, and the plastic viscosity, dynamic shear force, filtration amount and other data of the viscosity increasing agent are not involved. Chinese patent CN104311730A discloses a drilling fluid viscosity increasing agent. The viscosity increasing agent is polymerized by acrylamide, a sulfonic acid group-containing monomer A and a pyrrolidone monomer B according to a mass ratio of 10:(3-5):(0.7-1.5). The viscosity increasing agent can resist temperature up to 135℃, which cannot meet the drilling requirements of high-temperature and deep wells. American patent US7651980B2 discloses a ternary copolymer composed of acrylamide, 2-acrylamido-2-methylpropanesulfonic acid and N-vinyl pyrrolidone. The viscosity increasing agent can resist temperature up to 260℃, but the application under high salt conditions is not involved, and the application in a solid-free system is not involved. SUMMARY

[0004] One of the purposes of the present application is to provide a preparation method of a viscosity increasing and filtration reducing agent.

[0005] The second purpose of the present application is to provide a viscosity increasing and filtration reducing agent prepared by the preparation method, which can improve the viscosity, shear force and rock carrying performance of a solid-free drilling fluid system under high temperature, and effectively protect oil and gas layers.

[0006] The third purpose of the present application is to provide a drilling fluid comprising the viscosity increasing and filtration reducing agent.

[0007] In order to achieve the above purposes of the present application, the following technical solutions are adopted:

[0008] In a first aspect, the present application provides a method for preparing a viscosity increasing and fluid loss reducing agent, comprising the following steps:

[0009] The raw materials N-vinylpyrrolidone, 2-acrylamide-2-methylpropanesulfonic acid and allyl glyceryl ether are dissolved in water in a mass ratio of (1-3):(5-7):(1-4) to form an aqueous solution, the pH value of the aqueous solution is adjusted, a crosslinking agent and an initiator are added, and a viscosity increasing and fluid loss reducing agent is obtained by crosslinking copolymerization.

[0010] In some embodiments, the pH value of the aqueous solution is 6-8.

[0011] In some embodiments, the crosslinking agent is one or more selected from N’N methylene bisacrylamide and divinyl benzene.

[0012] In some embodiments, the crosslinking agent is added in an amount of 0.005%-0.05% of the total mass of N-vinylpyrrolidone, 2-acrylamide-2-methylpropanesulfonic acid and allyl glyceryl ether.

[0013] In some embodiments, the initiator is a mixture of azobisdimethylamidinum hydrochloride, an oxidizing agent and a reducing agent.

[0014] Preferably, the oxidizing agent is one or more selected from ammonium persulfate, potassium persulfate, hydrogen peroxide and sodium persulfate.

[0015] Preferably, the reducing agent is one or more selected from sodium bisulfite, ferrous ammonium sulfate and urea.

[0016] In some embodiments, azobisdimethylamidinum hydrochloride is added in an amount of 0.01%-0.3% of the total mass of N-vinylpyrrolidone, 2-acrylamide-2-methylpropanesulfonic acid and allyl glyceryl ether.

[0017] The oxidizing agent is added in an amount of 0.01%-0.5% of the total mass of N-vinylpyrrolidone, 2-acrylamide-2-methylpropanesulfonic acid and allyl glyceryl ether.

[0018] The reducing agent is added in an amount of 0.01%-0.5% of the total mass of N-vinylpyrrolidone, 2-acrylamide-2-methylpropanesulfonic acid and allyl glyceryl ether.

[0019] In some embodiments, the crosslinking copolymerization conditions include: first reacting at an initial reaction temperature of 5-15℃ for 30 min, then adjusting the temperature to 30-50℃, and reacting for 2-10 h.

[0020] In a specific embodiment, the method for preparing a viscosity increasing and fluid loss reducing agent specifically comprises the following steps:

[0021] (1) 1-3 parts by mass of N-vinylpyrrolidone, 5-7 parts by mass of 2-acrylamido-2-methylpropanesulfonic acid, and 1-4 parts by mass of allyl glyceryl ether are dissolved in deionized water to form a 20%-50% aqueous solution, and the pH is adjusted to 6-8 with sodium hydroxide;

[0022] (2) 0.01%-0.5% of an oxidizing agent, 0.01%-0.5% of a reducing agent, 0.01%-0.3% of azobisdimethylaminoformamide hydrochloride, and 0.005%-0.05% of a crosslinking agent are added, with the mass of the three monomers in step (1) being taken as 100%, and the mixture is stirred to dissolve the components;

[0023] (3) High-purity nitrogen is passed through the mixture for 30 min, the initial reaction temperature is set to 5-15℃, and after 30 min of reaction, the temperature is adjusted to 30-50℃;

[0024] (4) After 2-10 h of reaction, a tackifier and fluid loss reducer with a solid content of 20%-45% is obtained, and the product is dried and crushed to obtain a tackifier and fluid loss reducer powder.

[0025] In a second aspect, the present application provides a tackifier and fluid loss reducer prepared by the above preparation method.

[0026] In a third aspect, the present application provides a drilling fluid comprising the above tackifier and fluid loss reducer.

[0027] The present application selects N-vinylpyrrolidone, 2-acrylamido-2-methylpropanesulfonic acid, and allyl glyceryl ether to prepare a copolymer. The five-membered ring steric hindrance of N-vinylpyrrolidone is conducive to improving the temperature resistance. The amide group in 2-acrylamido-2-methylpropanesulfonic acid has good adsorption, which can improve the fluid loss performance of the product, and the sulfonic acid group is conducive to improving the temperature resistance of the product. The addition of allyl glyceryl ether is conducive to improving the structural complexity of the product and improving the temperature resistance.

[0028] Advantages:

[0029] The preparation method of the present application is simple and easy to implement, the reaction period is short, the temperature resistance of the obtained drilling fluid tackifier and fluid loss reducer can reach 200℃, the tackifying, shear force improving, and fluid loss reducing effects are good, and the present application can be widely applied to high-temperature solid-free drilling fluid systems and other various water-based drilling fluid systems, and has a wide application prospect.

[0030] The present application has been described in detail in the foregoing, but the above-described embodiments are merely illustrative in nature and are not intended to limit the present application. Furthermore, the present application is not limited by any theory described in the foregoing prior art or summary or in the following examples. DETAILED DESCRIPTION

[0031] The application will be further described in connection with the following examples. It should be noted that the following examples are provided for illustration purposes only and do not constitute a limitation on the scope of the application.

[0032] Unless otherwise specified, the raw materials, reagents, methods, etc. used in the examples are conventional raw materials, reagents, methods in the art.

[0033] The N-vinylpyrrolidone is from Shandong Xinghai Chemical Co., Ltd.;

[0034] The 2-acrylamide-2-methylpropanesulfonic acid is from Jiangsu Shenglun Chemical Technology Co., Ltd.;

[0035] The allyl glyceryl ether is from Shanghai Demao Chemical Co., Ltd.;

[0036] The N', N-methylenebisacrylamide is from Qingdao Huaweirui New Material Co., Ltd.

[0037] Example 1

[0038] (1) 5 g of N-vinylpyrrolidone, 35 g of 2-acrylamide-2-methylpropanesulfonic acid, and 10 g of allyl glyceryl ether were dissolved in deionized water cooled to 4°C to form a 35% aqueous solution, and sodium hydroxide was added to adjust the pH to neutral;

[0039] (2) 0.05 g of ammonium persulfate, 0.05 g of sodium bisulfite, and 0.15 g of azobisdimethylaminoformamide hydrochloride were added and stirred to dissolve, then 0.003 g of N', N-methylenebisacrylamide was added and stirred to dissolve;

[0040] (3) High-purity nitrogen was passed for 30 min, the temperature was set to 8°C, and the reaction was carried out for 30 min, then the temperature was raised to 30°C;

[0041] (4) After reacting for 10 h, an anti-high-temperature tackiness and fluid loss reducer block was obtained, which was dried and crushed to obtain an anti-high-temperature tackiness and fluid loss reducer powder.

[0042] Example 2

[0043] (1) 3 g of N-vinylpyrrolidone, 15 g of 2-acrylamide-2-methylpropanesulfonic acid, and 12 g of allyl glyceryl ether were dissolved in deionized water cooled to 4°C to form a 20% aqueous solution, and sodium hydroxide was added to adjust the pH to neutral;

[0044] (2) 0.15 g of ammonium persulfate, 0.15 g of sodium bisulfite, and 0.003 g of azobisdimethylaminoformamide hydrochloride were added and stirred to dissolve, then 0.0015 g of N', N-methylenebisacrylamide was added and stirred to dissolve;

[0045] (3) pass high-purity nitrogen gas for 30 min, set the temperature to 10℃, after reacting for 30 min, increase the temperature to 50℃;

[0046] (4) after reacting for 6 h, obtain anti-high-temperature tackiness and fluid loss reducer rubber blocks, dry and crush the rubber blocks to obtain anti-high-temperature tackiness and fluid loss reducer powders.

[0047] Example 3

[0048] (1) dissolve 2 g of N-vinylpyrrolidone, 12 g of 2-acrylamido-2-methylpropanesulfonic acid and 8 g of allyl glyceryl ether in deionized water cooled to 4℃, prepare a 50% aqueous solution, and adjust the pH to neutral with sodium hydroxide;

[0049] (2) add 0.0022 g of ammonium persulfate, 0.0022 g of sodium bisulfite and 0.0066 g of azobisdimethylaminoformamide hydrochloride, stir to dissolve, then add 0.011 g of N’N-methylenebisacrylamide, and stir to dissolve;

[0050] (3) pass high-purity nitrogen gas for 30 min, set the temperature to 5℃, after reacting for 30 min, increase the temperature to 40℃;

[0051] (4) after reacting for 2 h, obtain anti-high-temperature tackiness and fluid loss reducer rubber blocks, dry and crush the rubber blocks to obtain anti-high-temperature tackiness and fluid loss reducer powders.

[0052] Comparative Example 1

[0053] (1) dissolve 5 g of N-vinylpyrrolidone, 35 g of 2-acrylamido-2-methylpropanesulfonic acid and 10 g of acrylamide in deionized water cooled to 4℃, prepare a 35% aqueous solution, and adjust the pH to neutral with sodium hydroxide;

[0054] (2) add 0.05 g of ammonium persulfate, 0.05 g of sodium bisulfite and 0.15 g of azobisdimethylaminoformamide hydrochloride, stir to dissolve, then add 0.003 g of N’N-methylenebisacrylamide, and stir to dissolve;

[0055] (3) pass high-purity nitrogen gas for 30 min, set the temperature to 8℃, after reacting for 30 min, increase the temperature to 30℃;

[0056] (4) after reacting for 10 h, obtain anti-high-temperature tackiness and fluid loss reducer rubber blocks, dry and crush the rubber blocks to obtain anti-high-temperature tackiness and fluid loss reducer powders.

[0057] Comparative Example 2

[0058] (1) 35 g 2-acrylamide-2-methylpropanesulfonic acid, 10 g allyl glyceryl ether were dissolved in deionized water cooled to 4°C to form a 35% aqueous solution, and sodium hydroxide was added to adjust the pH to neutral;

[0059] (2) 0.05 g ammonium persulfate, 0.05 g sodium bisulfite, and 0.15 g azobisdimethylaminoformamide hydrochloride were added and stirred until dissolved, then 0.003 g N'-N methylenebisacrylamide was added and stirred until dissolved;

[0060] (3) High-purity nitrogen was passed for 30 min, the temperature was set to 8°C, and the reaction was carried out for 30 min, then the temperature was raised to 30°C;

[0061] (4) After 10 h of reaction, an anti-high-temperature tackiness and fluid loss reducer gel was obtained, which was dried and crushed to obtain an anti-high-temperature tackiness and fluid loss reducer powder.

[0062] The products of the examples and comparative examples were evaluated according to the following evaluation method:

[0063] (1) Rheological properties in water

[0064] 400 mL of water was taken, 4 g of the anti-high-temperature tackiness and fluid loss reducer powder after drying was added, 2 g of anhydrous sodium sulfite was added, and the mixture was placed in a high-speed stirrer and stirred at a speed of 10,000 r / min for 30 min. The viscosity of the aqueous solution of different products was then tested using a six-speed rotational viscometer. After the test, the aqueous solution was added to a high-temperature aging tank and placed in a high-temperature roller oven at 200°C for 16 h of hot rolling. After hot rolling, the mixture was taken out and cooled to room temperature. The rheological properties of the hot-rolled mixture were tested according to GB / T 16783.1-2014 "Petroleum and Natural Gas Industry Drilling Fluids Field Testing Part 1: Water-based Drilling Fluids". The evaluation results are shown in Table 1.

[0065] Table 1 Viscosity of aqueous solution of different products

[0066]

[0067]

[0068] As can be seen from Table 1, the tackiness and fluid loss reducer products obtained in the three examples have a very high viscosity of 1% aqueous solution, and the rheological properties change little before and after 200°C hot rolling, indicating that the tackiness and fluid loss reducer described in the application has good tackifying effect. In Comparative Example 1, the allyl glyceryl ether was replaced with acrylamide. As can be seen from the comparison results, the viscosity reduction rate of the tackifier obtained after replacing with acrylamide is 54.54%, which is not suitable for drilling sites. In Comparative Example 2, N-vinyl pyrrolidone was not added. As can be seen from the experimental results, the viscosity reduction rate is 46.34%, which is still relatively large and not suitable for drilling sites.

[0069] (2) Rheological properties in composite brine

[0070] Take 400 mL of clean water, place it on a high-speed stirrer, add 8 g of anti-high-temperature tackiness loss additive powder dried, high-speed stirring at 10000 r / min for 30 min, then add 2 g of anhydrous sodium sulfite, 20 g of potassium chloride, and 20 g of sodium formate, stirring for 30 min, then select a six-speed rotary viscometer to test the viscosity of different product aqueous solutions. After testing, the aqueous solution is added to a high-temperature aging tank and placed in a high-temperature roller oven at 200°C for 16 hours of hot rolling. After hot rolling, it is cooled to room temperature and the rheological properties after hot rolling are tested. The evaluation results are shown in Table 2.

[0071] Table 2 Viscosity of different product composite brine solutions

[0072]

[0073] As can be seen from Table 2, the salt resistance of the tackiness loss additive products prepared in the three examples is good, and the rheological properties before and after 200°C hot rolling change little, indicating that the tackiness loss additive described in the application has good temperature and salt resistance. The viscosity of Comparative Example 1 and Comparative Example 2 decreases significantly after adding salt, and the viscosity decreases significantly after hot rolling.

[0074] (3) Rheological properties and filtration properties in bentonite-based slurry

[0075] Take 400 mL of clean water, place it on a high-speed stirrer, add 16 g of sodium-based bentonite and 0.8 g of anhydrous sodium carbonate, high-speed stirring at 10000 r / min for 30 min, then stand for 24 h, make 4% bentonite-based slurry. At a speed of 10000 r / min, add 2 g of anti-high-temperature tackiness loss additive powder dried, 30 min later add 2 g of anhydrous sodium sulfite, stirring for 30 min, then according to GB / T 16783.1-2014 "Petroleum and Natural Gas Industry Drilling Fluids Field Testing Part 1: Water-based Drilling Fluids", test the rheological properties and filtration properties of different product aqueous solutions. The evaluation results are shown in Table 3.

[0076] Table 3 Rheological properties and filtration properties of base slurry after adding different products

[0077]

[0078] As can be seen from the results in Table 3, the viscosity, dynamic shear force and dynamic plastic ratio of the base paste can be greatly increased, and the filtration loss can be greatly reduced after the viscosity and filtration loss reducer products prepared in the three examples are added into the base paste, and the filtration loss reduction rate can be up to 81.43% after hot rolling at 200℃. The viscosity and filtration loss reducer has good shear increasing capacity, can greatly increase the dynamic plastic ratio of the base paste, and has significant flow regulating effect. The viscosity, dynamic shear force, dynamic plastic ratio of Comparative Example 1 and Comparative Example 2 are greatly reduced, and the filtration loss is greatly increased after hot rolling at 200℃.

[0079] As can be seen from the above examples and the evaluation results, the viscosity and filtration loss reducer has good viscosity increasing and filtration loss reducing effects, and has significant temperature resistance and salt resistance, and can be used as a viscosity and filtration loss reducer for oil drilling fluid under high temperature and high salt conditions.

[0080] The above examples are only used to illustrate the technical solutions of the present application, but not limit the present application. Although the present application has been described in detail with reference to the foregoing examples, it should be understood by those skilled in the art that the technical solutions recorded in the foregoing examples can be modified, or some or all of the technical features can be replaced by equivalents, without departing from the spirit and essence of the present application defined in the claims of the present application.

Claims

1. A method for preparing a viscosifying fluid loss additive, characterized in that, The method comprises the following steps: The raw materials N-vinyl pyrrolidone, 2-acrylamide-2-methylpropane sulfonic acid and allyl glyceryl ether are dissolved in water in a mass ratio of (1-3):(5-7):(1-4) to form an aqueous solution, the pH value of the aqueous solution is adjusted, a crosslinking agent and an initiator are added, and a crosslinking copolymerization is performed to obtain the tack-reducing fluid loss additive.

2. The production method according to claim 1, characterized by, The crosslinking agent is one or more selected from N'N methylene bisacrylamide and divinyl benzene.

3. The production method according to claim 2, characterized by, The crosslinking agent is added in an amount of 0.005%-0.05% of the total mass of N-vinyl pyrrolidone, 2-acrylamide-2-methylpropane sulfonic acid and allyl glyceryl ether.

4. The preparation method according to claim 1, characterized in that, The initiator is a mixture of azobisdimethylamidinum hydrochloride, an oxidizing agent and a reducing agent. The oxidizing agent is one or more selected from ammonium persulfate, potassium persulfate, hydrogen peroxide and sodium persulfate. The reducing agent is one or more selected from sodium bisulfite, ferrous ammonium sulfate and urea.

5. The preparation method according to claim 4, characterized in that, The azobisdimethylamidinum hydrochloride is added in an amount of 0.01%-0.3% of the total mass of N-vinyl pyrrolidone, 2-acrylamide-2-methylpropane sulfonic acid and allyl glyceryl ether. The oxidizing agent is added in an amount of 0.01%-0.5% of the total mass of N-vinyl pyrrolidone, 2-acrylamide-2-methylpropane sulfonic acid and allyl glyceryl ether. The reducing agent is added in an amount of 0.01%-0.5% of the total mass of N-vinyl pyrrolidone, 2-acrylamide-2-methylpropane sulfonic acid and allyl glyceryl ether.

6. The method of claim 1, wherein, The crosslinking copolymerization conditions include: first reacting at an initial reaction temperature of 5-15℃ for 30 min, then adjusting the temperature to 30-50℃, and reacting for 2h-10h.

7. The preparation method according to claim 1, characterized in that, The preparation method of the tack-reducing fluid loss additive comprises the following steps: (1) 1-3 parts by mass of N-vinyl pyrrolidone, 5-7 parts by mass of 2-acrylamide-2-methylpropane sulfonic acid and 1-4 parts by mass of allyl glyceryl ether are dissolved in deionized water to form a 20%-50% aqueous solution, and the pH value is adjusted to 6-8 with sodium hydroxide; (2) 0.01%-0.5% of the oxidizing agent, 0.01%-0.5% of the reducing agent, 0.01%-0.3% of the azobisdimethylamidinum hydrochloride and 0.005%-0.05% of the crosslinking agent are added, and the mixture is stirred to dissolve; (3) high-purity nitrogen is passed for 30 min, the initial reaction temperature is set to 5-15℃, and after reacting for 30 min, the temperature is adjusted to 30-50℃; (4) after reacting for 2h-10h, a tack-reducing fluid loss additive with a solid content of 20%-45% is obtained, and the product is dried and crushed to obtain a tack-reducing fluid loss additive powder.

8. A viscosifying fluid loss additive characterized in that, The tack-reducing fluid loss additive is prepared by the preparation method of any one of claims 1-7.

9. A drilling fluid, characterized by, The tack-reducing fluid loss additive of claim 8.

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