Tackifying filtrate reducer, preparation method thereof and drilling fluid

Abstract

The invention provides a tackifying filtrate reducer, a preparation method thereof and a drilling fluid, and belongs to the technical field of synthesis of treating agents for oil field drilling fluids. The preparation method comprises the following steps: dissolving raw materials N-vinyl pyrrolidone, 2-acrylamide-2-methylpropanesulfonic acid and allyl glyceryl ether in water according to a mass ratio of (1-3): (5-7): (1-4) to prepare an aqueous solution, adjusting the pH value of the aqueous solution, adding a cross-linking agent and an initiator, and carrying out cross-linking copolymerization to obtain the tackifying filtrate reducer. The tackifying filtrate reducer for the drilling fluid can resist the temperature of 200 DEG C, has good tackifying, shearing force improving and filter loss reducing effects, can be widely applied to a high-temperature solid-free drilling fluid system and other various water-based drilling fluid systems, and has a wide application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of synthetic treatment agents for oilfield drilling fluids, and in particular relates to a viscosity increasing and fluid loss reducing agent, a preparation method thereof, and drilling fluid. Background Art

[0002] In recent years, with the continuous deepening of exploration and development, the number of high-temperature deep wells has gradually increased, and more requirements have been put forward for the performance of drilling fluid treatment agents. Under high temperature (>180℃) and high salinity, the existing drilling fluid thickeners cannot maintain good rheological properties of the drilling fluid system. The only way to maintain good rheological properties and filtration properties of the drilling fluid is to increase the amount and continuously replenish the treatment agent. Therefore, the research and development of drilling fluid thickeners and filtration loss reducers with stable performance under high temperature and high salinity is particularly important.

[0003] In terms of temperature-resistant and salt-resistant thickeners, relevant technical personnel at home and abroad have actively explored. Chinese patent CN107759729A discloses a temperature-resistant and salt-resistant drilling fluid thickener, which uses N-vinyl pyrrolidone, 4-vinyl-1-(3-sulfopropyl) pyridine salt, and acrylamide as reaction monomers. The synthesized thickener can resist 3% calcium chloride, 3% magnesium chloride, and temperature resistance up to 180°C, but the amount of the thickener is large, which increases the drilling cost, and does not involve its plastic viscosity, dynamic shear force, filtration loss and other data. Chinese patent CN104311730A discloses a drilling fluid thickener, which is polymerized by acrylamide, sulfonic acid monomer A, and pyrrolidone monomer B in a mass ratio of 10: (3-5): (0.7-1.5). The thickener is resistant to 135°C and cannot meet the drilling requirements of high-temperature deep wells. U.S. Patent No. 7,651,980B2 discloses a terpolymer composed of acrylamide, 2-acrylamido-2-methylpropanesulfonic acid and N-vinylpyrrolidone. The viscosity enhancer is temperature resistant to 260°C, but does not involve application in high salt conditions, and the patent does not involve application in solid-free systems. Summary of the invention

[0004] One of the purposes of the present invention is to provide a method for preparing a viscosity increasing fluid loss reducing agent.

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

[0006] The third object of the present invention is to provide a drilling fluid comprising the viscosity increasing and fluid loss reducing agent.

[0007] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

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

[0009] The raw materials N-vinyl pyrrolidone, 2-acrylamide-2-methylpropane sulfonic acid and allyl glycerol ether are dissolved in water at a mass ratio of (1-3): (5-7): (1-4) to prepare 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 through crosslinking copolymerization.

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

[0011] In some embodiments, the cross-linking agent is one or more selected from N'N-methylenebisacrylamide and divinylbenzene.

[0012] In some embodiments, the amount of the cross-linking agent added is 0.005%-0.05% of the total mass of N-vinyl pyrrolidone, 2-acrylamide-2-methylpropane sulfonic acid and allyl glyceryl ether.

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

[0014] Preferably, the oxidant 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, ammonium ferrous sulfate, and urea.

[0016] In some embodiments, the amount of azobisisobutyramidine hydrochloride added is 0.01%-0.3% of the total mass of N-vinyl pyrrolidone, 2-acrylamide-2-methylpropanesulfonic acid and allyl glyceryl ether;

[0017] The amount of the oxidant added is 0.01%-0.5% of the total mass of N-vinyl pyrrolidone, 2-acrylamide-2-methylpropane sulfonic acid and allyl glyceryl ether;

[0018] The amount of the reducing agent added is 0.01%-0.5% of the total mass of N-vinyl pyrrolidone, 2-acrylamide-2-methylpropane sulfonic acid and allyl glyceryl ether.

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

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

[0021] (1) dissolving 1-3 parts by weight of N-vinyl pyrrolidone, 5-7 parts by weight of 2-acrylamide-2-methylpropanesulfonic acid, and 1-4 parts by weight of allyl glyceryl ether in deionized water to prepare a 20%-50% aqueous solution, and adjusting the pH to 6-8 with sodium hydroxide;

[0022] (2) based on the mass of the three monomers in step (1) being 100%, adding 0.01%-0.5% of an oxidizing agent, 0.01%-0.5% of a reducing agent, 0.01%-0.3% of azobisisobutylamidine hydrochloride, and 0.005%-0.05% of a cross-linking agent, and stirring to dissolve;

[0023] (3) Pass high-purity nitrogen for 30 minutes, set the initial reaction temperature to 5-15°C, and after 30 minutes of reaction, adjust the temperature to 30-50°C;

[0024] (4) After reacting for 2 h to 10 h, a viscosity increasing and fluid loss reducing agent with a solid content of 20% to 45% is obtained, and the product is dried and crushed to obtain a viscosity increasing and fluid loss reducing agent powder.

[0025] In a second aspect, the present invention provides a viscosity increasing and fluid loss reducing agent prepared by the above-mentioned preparation method.

[0026] In a third aspect, the present invention provides a drilling fluid comprising the above-mentioned viscosity increasing and fluid loss reducing agent.

[0027] The present invention selects three monomers of N-vinyl pyrrolidone, 2-acrylamide-2-methylpropane sulfonic acid and allyl glyceryl ether to prepare a copolymer. Among them, the five-membered ring contained in N-vinyl pyrrolidone has large steric hindrance, which is conducive to the improvement of temperature resistance. The amide group contained in 2-acrylamide-2-methylpropane sulfonic acid has good adsorption, which can improve the filtration loss reduction performance of the product. At the same time, the sulfonic acid group is conducive to the improvement of 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] Beneficial effects:

[0029] The preparation method of the invention is simple and easy, and the reaction cycle is short. The obtained drilling fluid viscosity increasing and filtrate reducing agent has a temperature resistance of up to 200°C, has good effects of viscosity increasing, improving shear force and reducing filtrate, can be widely used in high-temperature solid-free drilling fluid systems and other various water-based drilling fluid systems, and has broad application prospects.

[0030] The present invention has been described in detail above, but the above embodiments are only illustrative in nature and are not intended to limit the present invention. In addition, this article is not limited by any theory described in the above prior art or invention content or the following examples. DETAILED DESCRIPTION

[0031] The present invention is further described below in conjunction with examples. It should be noted that the following examples are provided for illustrative purposes only and do not constitute a limitation on the scope of protection claimed for the present invention.

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

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

[0034] 2-Acrylamide-2-methylpropanesulfonic acid was from Jiangsu Shenglun Chemical Technology Co., Ltd.;

[0035] Allyl glyceryl ether was from Shanghai Demao Chemical Co., Ltd.;

[0036] N'N-methylenebisacrylamide comes from Qingdao Huawei Ruisi New Materials Co., Ltd.

[0037] Example 1

[0038] (1) 5 g of N-vinyl pyrrolidone, 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 prepare a 35% aqueous solution, and sodium hydroxide was added to adjust the pH to neutral;

[0039] (2) adding 0.05 g of ammonium persulfate, 0.05 g of sodium bisulfite, and 0.15 g of azobisisobutylamidine hydrochloride, stirring to dissolve, and then adding 0.003 g of N'N-methylenebisacrylamide, stirring to dissolve;

[0040] (3) Pass high-purity nitrogen for 30 minutes, set the temperature to 8°C, and after reacting for 30 minutes, raise the temperature to 30°C;

[0041] (4) After reacting for 10 hours, a high temperature resistant viscosity increasing fluid loss reducer block is obtained, and the block is dried and crushed to obtain a high temperature resistant viscosity increasing fluid loss reducer powder.

[0042] Example 2

[0043] (1) 3 g of N-vinyl pyrrolidone, 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 prepare a 20% aqueous solution, and sodium hydroxide was added to adjust the pH to neutral;

[0044] (2) adding 0.15 g of ammonium persulfate, 0.15 g of sodium bisulfite, and 0.003 g of azobisisobutylamidine hydrochloride, stirring to dissolve, and then adding 0.0015 g of N'N-methylenebisacrylamide, stirring to dissolve;

[0045] (3) Pass high-purity nitrogen for 30 minutes, set the temperature to 10°C, and after reacting for 30 minutes, raise the temperature to 50°C;

[0046] (4) After reacting for 6 hours, a high temperature resistant viscosity increasing fluid loss reducing agent block is obtained, and the block is dried and crushed to obtain a high temperature resistant viscosity increasing fluid loss reducing agent powder.

[0047] Example 3

[0048] (1) 2 g of N-vinyl pyrrolidone, 12 g of 2-acrylamide-2-methylpropanesulfonic acid, and 8 g of allyl glyceryl ether were dissolved in deionized water cooled to 4° C. to prepare a 50% aqueous solution, and sodium hydroxide was added to adjust the pH to neutral;

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

[0050] (3) Pass high-purity nitrogen for 30 minutes, set the temperature to 5°C, and after reacting for 30 minutes, raise the temperature to 40°C;

[0051] (4) After reacting for 2 hours, a high temperature resistant viscosity increasing fluid loss reducing agent block is obtained, and the block is dried and crushed to obtain a high temperature resistant viscosity increasing fluid loss reducing agent powder.

[0052] Comparative Example 1

[0053] (1) 5 g of N-vinyl pyrrolidone, 35 g of 2-acrylamide-2-methylpropanesulfonic acid, and 10 g of acrylamide were dissolved in deionized water cooled to 4° C. to prepare a 35% aqueous solution, and sodium hydroxide was added to adjust the pH to neutral;

[0054] (2) adding 0.05 g of ammonium persulfate, 0.05 g of sodium bisulfite, and 0.15 g of azobisisobutylamidine hydrochloride, stirring to dissolve, and then adding 0.003 g of N'N-methylenebisacrylamide, stirring to dissolve;

[0055] (3) Pass high-purity nitrogen for 30 minutes, set the temperature to 8°C, and after reacting for 30 minutes, raise the temperature to 30°C;

[0056] (4) After reacting for 10 hours, a high temperature resistant viscosity increasing fluid loss reducer block is obtained, and the block is dried and crushed to obtain a high temperature resistant viscosity increasing fluid loss reducer powder.

[0057] Comparative Example 2

[0058] (1) 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 prepare a 35% aqueous solution, and sodium hydroxide was added to adjust the pH to neutral;

[0059] (2) adding 0.05 g of ammonium persulfate, 0.05 g of sodium bisulfite, and 0.15 g of azobisisobutylamidine hydrochloride, stirring to dissolve, and then adding 0.003 g of N'N-methylenebisacrylamide, stirring to dissolve;

[0060] (3) Pass high-purity nitrogen for 30 minutes, set the temperature to 8°C, and after reacting for 30 minutes, raise the temperature to 30°C;

[0061] (4) After reacting for 10 hours, a high temperature resistant viscosity increasing fluid loss reducer block is obtained, and the block is dried and crushed to obtain a high temperature resistant viscosity increasing fluid loss reducer powder.

[0062] The products of the embodiments and comparative examples were evaluated by the following method:

[0063] (1) Rheological properties in clean water

[0064] Take 400mL of clean water, add 4g of dried high temperature resistant viscosity increasing and filtrate reducing agent powder, and at the same time, add 2g of anhydrous sodium sulfite, place it on a high-speed stirrer, stir it at a speed of 10000r / min for 30min, and then use a six-speed rotary viscometer to test the viscosity of different product aqueous solutions. After the test, add the aqueous solution to a high-temperature aging tank, place it in a high-temperature roller furnace and heat roll it for 16h at 200℃. After the hot rolling is completed, take it out and cool it to room temperature. According to GB / T 16783.1-2014 "Field Test of Drilling Fluids in Petroleum and Natural Gas Industry Part 1: Water-based Drilling Fluids", test its rheological properties after hot rolling. The evaluation results are shown in Table 1.

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

[0066]

[0067]

[0068] From the results in Table 1, it can be seen that the viscosity increasing and fluid loss reducing agent products obtained in the three embodiments have extremely high viscosity in 1% aqueous solution, and the rheological properties before and after hot rolling at 200°C change very little, indicating that the viscosity increasing and fluid loss reducing agent of the present invention has a good viscosity increasing effect. In Comparative Example 1, allyl glyceryl ether is replaced with acrylamide. From the comparison results, it can be seen that the viscosity reduction rate of the obtained viscosity increasing agent after replacing with acrylamide is 54.54%, which is not suitable for drilling sites. Comparative Example 2 does not add N-vinyl pyrrolidone. From the experimental results, it can be seen that its viscosity reduction rate is 46.34%, which is still relatively large and is not suitable for drilling sites.

[0069] (2) Rheological properties in composite brine

[0070] Take 400mL of clean water, place it on a high-speed stirrer, add 8g of dried high-temperature resistant viscosity-increasing filtrate-reducing agent powder, stir at a speed of 10000r / min for 30min, then add 2g of anhydrous sodium sulfite, 20g of potassium chloride, and 20g of sodium formate in sequence, stir for 30min, and use a six-speed rotary viscometer to test the viscosity of different product aqueous solutions. After the test, add the aqueous solution to a high-temperature aging tank, place it in a high-temperature roller furnace at 200℃ for 16h, take it out after the hot rolling is completed, cool it to room temperature, and test its rheological properties after hot rolling. The evaluation results are shown in Table 2.

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

[0072]

[0073] From the results in Table 2, it can be seen that the viscosity increasing and fluid loss reducing agents prepared in the three embodiments have good salt resistance, and the rheological properties before and after hot rolling at 200°C change little, indicating that the viscosity increasing and fluid loss reducing agents of the present invention have good temperature and salt resistance. However, after adding salt to comparative examples 1 and 2, the viscosity decreases significantly, and the viscosity reduction rate after hot rolling is large.

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

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

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

[0077]

[0078] From the results in Table 3, it can be seen that after the viscosity-increasing and fluid loss-reducing agents prepared in the three embodiments are added to the base slurry, the viscosity, dynamic shear force and dynamic plastic ratio of the base slurry can be greatly increased, and its fluid loss can be greatly reduced. After hot rolling at 200°C, the fluid loss reduction rate can reach up to 81.43%. The viscosity-increasing and fluid loss-reducing agent of the present invention has good shear-increasing ability, can greatly increase the dynamic plastic ratio of the base slurry, and has a significant flow adjustment effect. After hot rolling at 200°C, the viscosity, dynamic shear force and dynamic plastic ratio of Comparative Examples 1 and 2 are greatly reduced, and the fluid loss is greatly increased.

[0079] It can be seen from the above examples and their evaluation results that the viscosity increasing and fluid loss reducing agent of the present invention has good viscosity increasing and fluid loss reducing effects, and has significant temperature and salt resistance effects, and can be used as a viscosity increasing and fluid loss reducing agent for petroleum drilling fluid under high temperature and high salt conditions.

[0080] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some or all of the technical features thereof may be replaced by equivalents, without departing from the spirit and essence of the claims of the present invention; and these modifications or replacements are still within the scope defined by the claims of the present invention.

Claims

1. A method for preparing a viscosity increasing fluid loss reducing agent, characterized in that: The following steps are involved: The raw materials N-vinyl pyrrolidone, 2-acrylamide-2-methylpropane sulfonic acid and allyl glycerol ether are dissolved in water at a mass ratio of (1-3): (5-7): (1-4) to prepare 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 through crosslinking copolymerization.

2. The preparation method according to claim 1, characterized in that: The cross-linking agent is one or more selected from N'N-methylenebisacrylamide and divinylbenzene.

3. The preparation method according to claim 2, characterized in that: The added amount of the cross-linking agent is 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 azobisisobutyramidine hydrochloride, an oxidant and a reducing agent; Preferably, the oxidant is one or more selected from ammonium persulfate, potassium persulfate, hydrogen peroxide, and sodium persulfate; Preferably, the reducing agent is one or more selected from sodium bisulfite, ammonium ferrous sulfate, and urea.

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

6. The preparation method according to claim 1, characterized in that: The conditions for cross-linking copolymerization include: first reacting at an initial reaction temperature of 5-15°C for 30 minutes, then adjusting the temperature to 30-50°C and reacting for 2h-10h.

7. The preparation method according to claim 1, characterized in that: The preparation method of the viscosity increasing and fluid loss reducing agent comprises the following steps: (1) dissolving 1-3 parts by weight of N-vinyl pyrrolidone, 5-7 parts by weight of 2-acrylamide-2-methylpropanesulfonic acid, and 1-4 parts by weight of allyl glyceryl ether in deionized water to prepare a 20%-50% aqueous solution, and adjusting the pH to 6-8 with sodium hydroxide; (2) based on the mass of the three monomers in step (1) being 100%, adding 0.01%-0.5% of an oxidizing agent, 0.01%-0.5% of a reducing agent, 0.01%-0.3% of azobisisobutylamidine hydrochloride, and 0.005%-0.05% of a cross-linking agent, and stirring to dissolve; (3) Pass high-purity nitrogen for 30 minutes, set the initial reaction temperature to 5-15°C, and after 30 minutes of reaction, adjust the temperature to 30-50°C; (4) After reacting for 2 h to 10 h, a viscosity increasing and fluid loss reducing agent with a solid content of 20% to 45% is obtained, and the product is dried and crushed to obtain a viscosity increasing and fluid loss reducing agent powder.

8. A viscosity increasing and fluid loss reducing agent, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 7.

9. A drilling fluid, characterized in that: It includes the viscosity increasing and fluid loss reducing agent as described in claim 8.

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