CN115572347A - High-temperature-resistant high-salt-resistant tackifying and shearing-improving agent for water-based drilling fluid and preparation method and application thereof - Google Patents

Abstract

The invention provides a high-temperature-resistant high-salt-resistant tackifying shear strength improver for water-based drilling fluid and a preparation method and application thereof. According to the invention, the temperature-resistant and salt-resistant tackifying cutting agent is prepared by performing emulsion polymerization on an acrylamide monomer, a temperature-resistant and salt-resistant monomer, a cationic monomer, a methacrylic acid-2- (2-ureido-4, [1H ] -6-methylpyrimidinone) -ethyl ester (UPyMA), and a chemical cross-linking agent triallyl, wherein the UPyMA monomer can form a quadruple hydrogen bond with stronger bond energy, so that the polymer has excellent high-temperature stability; the introduction of the acrylamide monomer increases the molecular weight of the polymer and endows the polymer with excellent tackifying capability; the introduction of the temperature-resistant and salt-resistant monomer enhances the temperature-resistant and salt-resistant hydration capacity of the polymer; the introduction of the cationic monomer significantly reduces the fluid loss. The tackifying and cutting-improving agent prepared by the invention still has excellent tackifying, cutting-improving and filtrate loss reducing performances after being aged in a high-salt (saturated salt) environment at a high temperature (200 ℃).

Description

A kind of anti-high-temperature anti-high-salt viscosity-increasing and shearing agent for water-based drilling fluid and its preparation method and application

technical field

The invention relates to a high-temperature, high-salt, viscosity-increasing and shearing agent for water-based drilling fluids, a preparation method and application thereof, and belongs to the technical field of petroleum drilling fluids.

Background technique

With the continuous growth of the global economy and the increasing consumption of oil and natural gas, the target layers of oil and gas exploration and development have gradually expanded from the middle and shallow layers in the past to deep and ultra-deep layers (burial depth > 6000m). Water-based drilling fluid is a dispersed system composed of slurry-making clay, chemical additives, and water. It is very important for wellbore stability, reservoir protection, and increase in ROP during drilling. However, the complex geological conditions of high temperature (>200°C), high pressure (>140MPa) and salt-gypsum formation in deep reservoirs can easily cause degradation, cross-linking, curling and hydrolysis of polymer additives in water-based drilling fluids, which in turn leads to water-based drilling fluids. The failure of the drilling fluid function poses a huge challenge to the safety, economy and efficiency of the drilling process.

In recent years, in order to meet the needs of fast and high-quality drilling and reservoir protection in deep and ultra-deep wells at the same time, water-based drilling fluids with no/low soil phase polymers that can improve the rate of penetration, shorten the drilling and completion cycle, and protect the reservoir have been obtained. Extensive research and application. One of the core treatment agents for water-based drilling fluids with no/low soil phase polymers is a viscosity-increasing and shear-increasing agent, which not only has the effects of increasing viscosity, increasing shear, and reducing fluid loss, but also has coating inhibition. At present, the commonly used drilling fluid viscosity-increasing and cutting-increasing agents mainly include synthetic polymers represented by acrylamide polymers (such as 80A51, FA367, etc.) and biopolymers represented by xanthan gum and carboxymethyl cellulose. They usually gradually fail due to thermal degradation at temperatures exceeding 150°C, resulting in no/low soil polymer water-based drilling fluids that cannot meet the drilling needs of deep and ultra-deep wells.

Chinese patent document CN109266318A discloses a method for preparing a high-temperature viscosity-increasing and shearing-lifting agent for water-based drilling fluids, which uses starch as the main raw material and has excellent environmental performance. Chinese patent CN111171225A discloses a hyperbranched polymer viscosity-increasing and shearing agent synthesized by inverse emulsion polymerization, which does not require drying and crushing, and can reduce the cost and processing costs. However, the temperature resistance of the above two viscosity-increasing and shearing agents is 150°C, and the salt resistance performance has not been evaluated. With the exploration and development of deep and ultra-deep oil and gas resources, these two viscosity-increasing and shearing agents cannot be effectively used in deep and ultra-deep wells. effect. Chinese patent document CN107163184A provides a high-temperature anti-shearing agent for solid-free drilling fluid, including 60-70 parts by weight of solvent water, 15-25 parts by weight of the first monomer, and 20-30 parts by weight of the second monomer , 5-7 parts by weight of cationic monomer, 2-3 parts by weight of 5wt.% EDTA aqueous solution, 2-3 parts by weight of 3wt.% aqueous solution of reducing agent, 2-3 parts by weight of 3wt.% aqueous solution of oxidant, 1-2 parts by weight of chain transfer agent and 0.1-0.2% of ammonium ferrous sulfate accounting for the total mass of the first monomer, the second monomer and the cationic monomer; wherein, the first monomer is 2-acrylamide 2-methylpropanesulfonic acid, sodium methacrylsulfonate, sodium p-vinylbenzenesulfonate, sodium 2-acrylamido-2-methylpropanesulfonate or 2-acrylamido-2-methyl Potassium propanesulfonate; the second monomer is acrylamide, methacrylamide, N,N-dimethylacrylamide or N,N-diethylacrylamide; the cationic monomer is methacrylamide Oxyethyltrimethylammonium chloride, acryloyloxyethyltrimethylammonium chloride or dimethyl diallylammonium chloride, however, their temperature resistance can only reach 170°C, which cannot be applied to deep and ultra-deep formations .

Therefore, how to enhance the stability of the viscosity-increasing and shear-increasing agent for water-based drilling fluids in high-temperature and high-salt environments, maintain the performance of viscosity-increasing and shearing-increasing, and improve the anti-high temperature and high-salt resistance of rich deep and ultra-deep layers without/low soil phase polymer water The basic research of base drilling fluid is of great significance.

Contents of the invention

Aiming at the deficiencies of the prior art, especially the problems that the existing water-based drilling fluid viscosity-increasing and shearing agents are easily degraded and cross-linked in a high-temperature environment, and easily curled and agglomerated in a salt water environment, the present invention provides a water-based High-temperature and high-salt viscosity-increasing and shearing-lifting agent for drilling fluid, preparation method and application thereof. The viscosity-increasing and shear-increasing agent of the invention can resist high temperature (≥200° C.), resist high salt (saturated salt), and can realize the functions of increasing viscosity, increasing shear and reducing fluid loss.

Technical scheme of the present invention is as follows:

A method for preparing a high-temperature and high-salt viscosity-increasing and shearing agent for water-based drilling fluids, comprising the following steps:

(1) Add isocyanoethyl methacrylate to the 2-amino-4-hydroxyl-6-methylpyrimidine solution, and then react; after the reaction is completed, filter, wash, and dry to obtain monomer methacrylic acid - 2-(2-ureido-4[1H]-6-methylpyrimidinone)-ethyl ester (UPyMA);

(2) Dissolving the emulsifier in water and shearing emulsification to obtain emulsion A; then adding the monomer methacrylic acid-2-(2-ureido-4[1H] obtained in step (1) to the obtained emulsion A -6-methylpyrimidinone)-ethyl ester (UPyMA), after emulsification by shearing, micellar solution B is obtained;

(3) adding acrylamide monomers, temperature-resistant and salt-resistant monomers, cationic monomers, and cross-linking agents into water, and stirring evenly to obtain monomer solution C;

(4) Mix the micellar emulsion B with the monomer solution C, and after emulsification by shearing, adjust the pH value of the system to obtain the mixed reaction solution D; after passing the obtained mixed reaction solution D through nitrogen to remove oxygen, heat up to the reaction temperature, add triggering Agent, thermally initiates free radical polymerization reaction; after the reaction is completed, lower the temperature to obtain high temperature and high salt viscosity increasing and cutting agent for water-based drilling fluid.

Preferably according to the present invention, the 2-amino-4-hydroxyl-6-methylpyrimidine solution in step (1) is obtained by dissolving 2-amino-4-hydroxyl-6-methylpyrimidine in an organic solvent. The organic solvent is dimethylsulfoxide or N,N-dimethylformamide; the ratio of the quality of the 2-amino-4-hydroxyl-6-methylpyrimidine to the volume of the organic solvent is 0.1-0.5g: 2mL, more preferably 0.2-0.3g:2mL; the temperature at which the 2-amino-4-hydroxy-6-methylpyrimidine dissolves is 80-150°C, more preferably 90-120°C.

Preferably according to the present invention, the mass ratio of 2-amino-4-hydroxyl-6-methylpyrimidine and isocyanoethyl methacrylate described in step (1) is 1:1-1.5, more preferably 1: 1.2-1.4.

Preferably according to the present invention, the reaction temperature in step (1) is 80-150°C, more preferably 90-120°C; the reaction time is 1-60min, more preferably 10-30min.

Preferably, according to the present invention, the washing in step (1) is washing with acetone for 2-6 times, more preferably 3-5 times; the drying is vacuum drying at room temperature for 20-30 hours.

Preferably according to the present invention, the emulsifier described in step (2) is one or both of sodium dodecyl sulfate (SDS), sodium dodecylbenzenesulfonate (SDBS), emulsifier OP-10 The combination of the above; the ratio of the mass of the emulsifier to the volume of water is 0.05-0.5g:20mL, more preferably 0.1-0.2g:20mL.

Preferably according to the present invention, the quality of the monomer methacrylic acid-2-(2-ureido-4[1H]-6-methylpyrimidinone)-ethyl ester (UPyMA) in step (2) is the same as that of water The volume ratio is 0.05-0.5g:20mL, more preferably 0.1-0.2g:20mL.

Preferably according to the present invention, the shear emulsification rate in step (2) is 500-3000r/min, more preferably 1000-2000r/min; the shear emulsification time is 10-60min.

Preferably according to the present invention, the acrylamide monomer described in step (3) is acrylamide (AM), N,N-dimethylacrylamide (DMAA), isopropylacrylamide (NIPAM); the acrylamide The ratio of the mass of amide monomer to the volume of water is 0.1-0.2g:1mL.

Preferably according to the present invention, the temperature-resistant and salt-resistant monomer described in step (3) is 2-acrylamido-2-methylpropanesulfonic acid (AMPS), sodium styrenesulfonate (SSS), vinylsulfonic acid Sodium (VS); the cationic monomers are diallyldimethylammonium chloride (DMDAAC) and acryloyloxyethyltrimethylammonium chloride (DAC).

Preferably according to the present invention, the mass ratio of the acrylamide monomer, the temperature-resistant and salt-resistant monomer, and the cationic monomer described in step (3) is 1:0.3-2:0.2-1, more preferably 1:0.8- 1.5:0.4-0.8.

Preferably according to the present invention, the cross-linking agent described in step (3) is triallylamine or N, N-methylenebisacrylamide; The ratio of the total mass of the salt-resistant monomer to the cationic monomer is 0.01-0.05:1, more preferably 0.02-0.03:1.

Preferably according to the present invention, monomer methacrylic acid-2-(2-ureido-4[1H]-6-methylpyrimidinone)-ethyl ester (UPyMA) in the micellar emulsion B described in step (4) The mass ratio of the acrylamide monomer to the monomer solution C is 1:5-8.

Preferably according to the present invention, the shear emulsification rate in step (4) is 500-3000r/min, more preferably 1000-2000r/min; the shear emulsification time is 10-60min.

Preferably according to the present invention, the pH value of the mixed reaction solution D described in step (4) is 3-10, more preferably 5-9; use the pH of the alkali solution condition system, the alkali is sodium hydroxide, the The mass fraction of the alkali solution is 10-30%.

Preferably according to the present invention, initiator described in step (4) is potassium persulfate (KPS), ammonium persulfate (APS), azobisisobutyronitrile (AIBN), azobisisobutylamidine hydrochloride ( V50); the ratio of the mass of the initiator to the total mass of the acrylamide monomer, the temperature-resistant and salt-resistant monomer, and the cationic monomer is 0.01-0.05:1, more preferably 0.02-0.03:1.

Preferably according to the present invention, the reaction temperature in step (4) is 50-80°C, more preferably 55-70°C; the reaction time is 2-6h, more preferably 3-5h.

A high-temperature, high-salt, viscosity-increasing and cutting-lifting agent for water-based drilling fluid is prepared by the above-mentioned preparation method.

According to the present invention, the application of the above-mentioned water-based drilling fluid anti-high temperature and high-salt viscosity-increasing shear raising agent in water-based drilling fluid; The concentration of sticky cutting agent is 5-10g/L.

Technical characteristics of the present invention and beneficial effect are as follows:

1. The monomer UPyMA capable of forming quadruple hydrogen bonds is introduced into the viscosity-increasing and shearing agent of the present invention, and the quadruple hydrogen bonds with larger bond energy form stronger physical cross-linking points, which limit the number of polymer chain segments. The ability to exercise endows the polymer with a strong spatial network structure, which in turn makes the polymer have excellent viscosity-increasing and cutting-lifting capabilities.

2. The present invention uses a small amount of triallylamine as a chemical cross-linking agent in the synthesis process of the polymer to carry out slight and moderate chemical cross-linking on the polymer, thereby increasing the temperature resistance of the polymer tackifier.

3. The present invention introduces acrylamide monomers, which can not only improve the high-temperature hydrolysis resistance of polymers but also increase the molecular weight of polymers, and further enhance the temperature-resistant and viscosity-increasing capabilities of polymers; introduce temperature-resistant and salt-resistant monomers , which can improve the temperature and salt resistance of the polymer; the cationic monomer is introduced, which enhances the adsorption capacity of the polymer on the surface of bentonite, enhances the interaction between the polymer and bentonite particles, and the protective gel of the polymer ability, and then maintain the dispersibility of bentonite particles, so that the viscosifier has fluid loss control performance.

4. The polymer viscosifier synthesized by the present invention has excellent resistance to temperature and salt, and after aging in a high-temperature, saturated salt environment at 200°C, it still has excellent viscosity-increasing, cutting-increasing, and fluid loss-reducing capabilities. The liquid field has broad application prospects.

Description of drawings

Fig. 1 is the one-dimensional hydrogen nuclear magnetic spectrum of methacrylic acid-2-(2-ureido-4[1H]-6-methylpyrimidinone)-ethyl ester (UPyMA) synthesized in Example 5.

Fig. 2 is the thermal gravimetric analysis diagram of the high temperature and high salt viscosity increasing and cutting agent synthesized in Example 5.

detailed description

The present invention will be further described below in conjunction with specific examples, but not limited thereto.

At the same time, the experimental methods described in the following examples, unless otherwise specified, are conventional methods; the reagents, materials and equipment, unless otherwise specified, can be obtained from commercial sources.

Example 1

A method for preparing a high-temperature and high-salt viscosity-increasing and shearing agent for water-based drilling fluids, comprising the following steps:

(1) Preparation of monomeric methacrylic acid-2-(2-ureido-4[1H]-6-methylpyrimidinone)-ethyl ester UPyMA

(1.1) Add 2g of 2-amino-4-hydroxy-6-methylpyrimidine into a 100mL round bottom flask, add 20mL of dimethyl sulfoxide (DMSO), place the flask in an oil bath at 100°C, and stir magnetically Until the solid is completely dissolved to obtain a dimethyl sulfoxide solution of 2-amino-4-hydroxyl-6-methylpyrimidine;

(1.2) 2.4g isocyanoethyl methacrylate is added to the dimethyl sulfoxide solution of 2-amino-4-hydroxyl-6-methylpyrimidine obtained in the above step (1.1) through a constant pressure dropping funnel , the dropping time is 5min. After the dropping is completed, react at 100°C for 15min. The reacted product is naturally cooled to room temperature, and then transferred to a suction filtration device containing a sand core funnel, and a white solid is obtained by suction filtration. The solid was washed with acetone, then suction filtered again, and the suction filtration and washing were repeated 3 times, and finally the obtained solid was dried in a vacuum oven at room temperature for 24 hours to obtain the monomer methacrylic acid-2-(2-ureido-4[1H] -6-methylpyrimidinone)-ethyl ester (UPyMA).

(2) Preparation of temperature-resistant and salt-resistant polymer viscosity-increasing and shearing agent

(2.1) Add 1 g of emulsifier sodium lauryl sulfate and 200 mL of distilled water into a 250 mL beaker, and use a shear emulsifier to shear and emulsify for 30 min at a stirring speed of 1000 r/min to obtain emulsion A;

(2.2) Add 1 g of monomer methacrylic acid-2-(2-ureido-4[1H]-6-methylpyrimidinone)-ethyl ester UPyMA obtained in step (1.2) to the emulsion obtained in step (2.1) In A, use a shear emulsifier to shear and emulsify for 30 minutes at a stirring speed of 1000r/min to obtain micellar solution B;

(2.3) 5g N,N-dimethylacrylamide (DMAA), 3g 2-acrylamido-2-methylpropanesulfonic acid (AMPS), 2g diallyldimethylammonium chloride (DMDAAC) , 0.22g chemical cross-linking agent triallylamine was dissolved in 30mL water, and after fully stirring, monomer solution C was obtained;

(2.4) Mix all the micellar emulsion B obtained in step (2.2) with all the monomer solution C obtained in step (2.3), use a shear emulsifier to emulsify for 30 minutes at a stirring speed of 1000 r/min, and use a mass fraction of 20 % NaOH aqueous solution to adjust the pH of the mixed solution to 5 to obtain a mixed reaction solution D;

(2.5) Fully deoxygenate the mixed reaction solution D in a nitrogen atmosphere, raise the temperature to 55°C, add 0.22g of initiator potassium persulfate (KPS), and polymerize at 55°C for 4h. After the reaction, naturally cool to room temperature , that is, the anti-high temperature and anti-high salt viscosity-increasing and shearing agent for water-based drilling fluid.

Example 2

A method for preparing a high-temperature and high-salt viscosity-increasing and shearing agent for water-based drilling fluids, comprising the following steps:

(1) Preparation of monomeric methacrylic acid-2-(2-ureido-4[1H]-6-methylpyrimidinone)-ethyl ester UPyMA

(1.1) Add 2g of 2-amino-4-hydroxy-6-methylpyrimidine into a 100mL round bottom flask, add 20mL of dimethyl sulfoxide (DMSO), place the flask in an oil bath at 100°C, and stir magnetically Until the solid is completely dissolved to obtain a dimethyl sulfoxide solution of 2-amino-4-hydroxyl-6-methylpyrimidine;

(1.2) 2.4g isocyanoethyl methacrylate is added to the dimethyl sulfoxide solution of 2-amino-4-hydroxyl-6-methylpyrimidine obtained in the above step (1.1) through a constant pressure dropping funnel , the dropping time is 5min. After the dropping is completed, react at 100°C for 15min. The reacted product is naturally cooled to room temperature, and then transferred to a suction filtration device containing a sand core funnel, and a white solid is obtained by suction filtration. The solid was washed with acetone, then suction filtered again, and the suction filtration and washing were repeated 3 times, and finally the obtained solid was dried in a vacuum oven at room temperature for 24 hours to obtain the monomer methacrylic acid-2-(2-ureido-4[1H] -6-methylpyrimidinone)-ethyl ester (UPyMA).

(2) Preparation of temperature-resistant and salt-resistant polymer viscosity-increasing and shearing agent

(2.1) Add 1 g of emulsifier sodium lauryl sulfate and 200 mL of distilled water into a 250 mL beaker, and use a shear emulsifier to shear and emulsify for 30 min at a stirring speed of 1000 r/min to obtain emulsion A;

(2.2) Add 1 g of monomer methacrylic acid-2-(2-ureido-4[1H]-6-methylpyrimidinone)-ethyl ester UPyMA obtained in step (1.2) to the emulsion obtained in step (2.1) In A, use a shear emulsifier to shear and emulsify for 30 minutes at a stirring speed of 1000r/min to obtain micellar solution B;

(2.3) 5g N,N-dimethylacrylamide (DMAA), 3g 2-acrylamido-2-methylpropanesulfonic acid (AMPS), 2g diallyldimethylammonium chloride (DMDAAC) , 0.22g chemical cross-linking agent triallylamine was dissolved in 30mL water, and after fully stirring, monomer solution C was obtained;

(2.4) Mix all the micellar emulsion B obtained in step (2.2) with all the monomer solution C obtained in step (2.3), use a shear emulsifier to emulsify for 30 minutes at a stirring speed of 1000 r/min, and use a mass fraction of 20% NaOH aqueous solution to adjust the pH of the mixed solution to 7 to obtain a mixed reaction solution D;

(2.5) Fully deoxygenate the mixed reaction solution D in a nitrogen atmosphere, raise the temperature to 55°C, add 0.22g of initiator potassium persulfate (KPS), and polymerize at 55°C for 4h. After the reaction, naturally cool to room temperature , that is, the anti-high temperature and anti-high salt viscosity-increasing and shearing agent for water-based drilling fluid.

Example 3

A method for preparing a high-temperature and high-salt viscosity-increasing and shearing agent for water-based drilling fluids, comprising the following steps:

(1) Preparation of monomeric methacrylic acid-2-(2-ureido-4[1H]-6-methylpyrimidinone)-ethyl ester UPyMA

(1.1) Add 2g of 2-amino-4-hydroxy-6-methylpyrimidine into a 100mL round bottom flask, add 20mL of dimethyl sulfoxide (DMSO), place the flask in an oil bath at 100°C, and stir magnetically Until the solid is completely dissolved to obtain a dimethyl sulfoxide solution of 2-amino-4-hydroxyl-6-methylpyrimidine;

(1.2) 2.4g isocyanoethyl methacrylate is added to the dimethyl sulfoxide solution of 2-amino-4-hydroxyl-6-methylpyrimidine obtained in the above step (1.1) through a constant pressure dropping funnel , the dropping time is 5min. After the dropping is completed, react at 100°C for 15min. The reacted product is naturally cooled to room temperature, and then transferred to a suction filtration device containing a sand core funnel, and a white solid is obtained by suction filtration. The solid was washed with acetone, then suction filtered again, and the suction filtration and washing were repeated 3 times, and finally the obtained solid was dried in a vacuum oven at room temperature for 24 hours to obtain the monomer methacrylic acid-2-(2-ureido-4[1H] -6-methylpyrimidinone)-ethyl ester (UPyMA).

(2) Preparation of temperature-resistant and salt-resistant polymer viscosity-increasing and shearing agent

(2.1) Add 1 g of emulsifier sodium lauryl sulfate and 200 mL of distilled water into a 250 mL beaker, and use a shear emulsifier to shear and emulsify for 30 min at a stirring speed of 1000 r/min to obtain emulsion A;

(2.2) Add 1 g of monomer methacrylic acid-2-(2-ureido-4[1H]-6-methylpyrimidinone)-ethyl ester UPyMA obtained in step (1.2) to the emulsion obtained in step (2.1) In A, use a shear emulsifier to shear and emulsify for 30 minutes at a stirring speed of 1000r/min to obtain micellar solution B;

(2.3) 5g N,N-dimethylacrylamide (DMAA), 3g 2-acrylamido-2-methylpropanesulfonic acid (AMPS), 2g diallyldimethylammonium chloride (DMDAAC) , 0.22g chemical cross-linking agent triallylamine was dissolved in 30mL water, and after fully stirring, monomer solution C was obtained;

(2.4) Mix all the micellar emulsion B obtained in step (2.2) with all the monomer solution C obtained in step (2.3), use a shear emulsifier to emulsify for 30 minutes at a stirring speed of 1000 r/min, and use a mass fraction of 20% NaOH aqueous solution to adjust the pH of the mixed solution to 9 to obtain the mixed reaction solution D;

(2.5) Fully deoxygenate the mixed reaction solution D in a nitrogen atmosphere, raise the temperature to 55°C, add 0.22g of initiator potassium persulfate (KPS), and polymerize at 55°C for 4h. After the reaction, naturally cool to room temperature , that is, the anti-high temperature and anti-high salt viscosity-increasing and shearing agent for water-based drilling fluid.

Example 4

A method for preparing a high-temperature and high-salt viscosity-increasing and shearing agent for water-based drilling fluids, comprising the following steps:

(1) Preparation of monomeric methacrylic acid-2-(2-ureido-4[1H]-6-methylpyrimidinone)-ethyl ester UPyMA

(1.1) Add 2g of 2-amino-4-hydroxy-6-methylpyrimidine into a 100mL round bottom flask, add 20mL of dimethyl sulfoxide (DMSO), place the flask in an oil bath at 100°C, and stir magnetically Until the solid is completely dissolved to obtain a dimethyl sulfoxide solution of 2-amino-4-hydroxyl-6-methylpyrimidine;

(1.2) 2.4g isocyanoethyl methacrylate is added to the dimethyl sulfoxide solution of 2-amino-4-hydroxyl-6-methylpyrimidine obtained in the above step (1.1) through a constant pressure dropping funnel , the dropping time is 5min. After the dropping is completed, react at 100°C for 15min. The reacted product is naturally cooled to room temperature, and then transferred to a suction filtration device containing a sand core funnel, and a white solid is obtained by suction filtration. The solid was washed with acetone, then suction filtered again, and the suction filtration and washing were repeated 3 times, and finally the obtained solid was dried in a vacuum oven at room temperature for 24 hours to obtain the monomer methacrylic acid-2-(2-ureido-4[1H] -6-methylpyrimidinone)-ethyl ester (UPyMA).

(2) Preparation of temperature-resistant and salt-resistant polymer viscosity-increasing and shearing agent

(2.1) Add 1 g of emulsifier sodium lauryl sulfate and 200 mL of distilled water into a 250 mL beaker, and use a shear emulsifier to shear and emulsify for 30 min at a stirring speed of 1000 r/min to obtain emulsion A;

(2.2) Add 1 g of monomer methacrylic acid-2-(2-ureido-4[1H]-6-methylpyrimidinone)-ethyl ester UPyMA obtained in step (1.2) to the emulsion obtained in step (2.1) In A, use a shear emulsifier to shear and emulsify for 30 minutes at a stirring speed of 1000r/min to obtain micellar solution B;

(2.3) 5g N,N-dimethylacrylamide (DMAA), 8g 2-acrylamido-2-methylpropanesulfonic acid (AMPS), 3g diallyldimethylammonium chloride (DMDAAC) , 0.34g chemical cross-linking agent triallylamine was dissolved in 30mL water, and after fully stirring, monomer solution C was obtained;

(2.4) Mix all the micellar emulsion B obtained in step (2.2) with all the monomer solution C obtained in step (2.3), use a shear emulsifier to emulsify for 30 minutes at a stirring speed of 1000 r/min, and use a mass fraction of 20% NaOH aqueous solution to adjust the pH of the mixed solution to 9 to obtain the mixed reaction solution D;

(2.5) Fully deoxygenate the mixed reaction liquid D in a nitrogen atmosphere, raise the temperature to 55°C, add 0.34g of initiator potassium persulfate (KPS), and polymerize at 55°C for 4h. After the reaction, cool naturally to room temperature , that is, the anti-high temperature and anti-high salt viscosity-increasing and shearing agent for water-based drilling fluid.

Example 5

A method for preparing a high-temperature and high-salt viscosity-increasing and shearing agent for water-based drilling fluids, comprising the following steps:

(1) Preparation of monomeric methacrylic acid-2-(2-ureido-4[1H]-6-methylpyrimidinone)-ethyl ester UPyMA

(1.1) Add 2g of 2-amino-4-hydroxy-6-methylpyrimidine into a 100mL round bottom flask, add 20mL of dimethyl sulfoxide (DMSO), place the flask in an oil bath at 100°C, and stir magnetically Until the solid is completely dissolved to obtain a dimethyl sulfoxide solution of 2-amino-4-hydroxyl-6-methylpyrimidine;

(1.2) 2.4g isocyanoethyl methacrylate is added to the dimethyl sulfoxide solution of 2-amino-4-hydroxyl-6-methylpyrimidine obtained in the above step (1.1) through a constant pressure dropping funnel , the dropping time is 5min. After the dropping is completed, react at 100°C for 15min. The reacted product is naturally cooled to room temperature, and then transferred to a suction filtration device containing a sand core funnel, and a white solid is obtained by suction filtration. The solid was washed with acetone, then suction filtered again, and the suction filtration and washing were repeated 3 times, and finally the obtained solid was dried in a vacuum oven at room temperature for 24 hours to obtain the monomer methacrylic acid-2-(2-ureido-4[1H] -6-methylpyrimidinone)-ethyl ester (UPyMA).

(2) Preparation of temperature-resistant and salt-resistant polymer viscosity-increasing and shearing agent

(2.1) Add 1 g of emulsifier sodium lauryl sulfate and 200 mL of distilled water into a 250 mL beaker, and use a shear emulsifier to shear and emulsify for 30 min at a stirring speed of 1000 r/min to obtain emulsion A;

(2.2) Add 1 g of monomer methacrylic acid-2-(2-ureido-4[1H]-6-methylpyrimidinone)-ethyl ester UPyMA obtained in step (1.2) to the emulsion obtained in step (2.1) In A, use a shear emulsifier to shear and emulsify for 30 minutes at a stirring speed of 1000r/min to obtain micellar solution B;

(2.3) 6g N,N-dimethylacrylamide (DMAA), 7g 2-acrylamido-2-methylpropanesulfonic acid (AMPS), 3g diallyldimethylammonium chloride (DMDAAC) , 0.34g chemical cross-linking agent triallylamine was dissolved in 30mL water, and after fully stirring, monomer solution C was obtained;

(2.4) Mix all the micellar emulsion B obtained in step (2.2) with all the monomer solution C obtained in step (2.3), use a shear emulsifier to emulsify for 30 minutes at a stirring speed of 1000 r/min, and use a mass fraction of 20% NaOH aqueous solution to adjust the pH of the mixed solution to 9 to obtain the mixed reaction solution D;

(2.5) Fully deoxygenate the mixed reaction liquid D in a nitrogen atmosphere, raise the temperature to 55°C, add 0.34g of initiator potassium persulfate (KPS), and polymerize at 55°C for 4h. After the reaction, cool naturally to room temperature , that is, the anti-high temperature and anti-high salt viscosity-increasing and shearing agent for water-based drilling fluid.

The one-dimensional hydrogen NMR spectrum of the monomer methacrylic acid-2-(2-ureido-4[1H]-6-methylpyrimidinone)-ethyl ester (UPyMA) obtained in this example is shown in FIG. 1 .

The thermogravimetric analysis diagram of the anti-high temperature and high-salt viscosity-increasing and shearing agent for water-based drilling fluid obtained in this example is shown in Figure 2. It can be seen from Figure 2 that a small amount of weight loss of the viscosity-increasing agent occurs before 130 ° C, mainly due to Caused by the volatilization of a small amount of water molecules in the sample; between 130°C and 270°C, the bound water absorbed by strong hydrophilic groups such as amide groups and sulfonic acid groups in the molecular sample begins to volatilize when heated; 270°C to 360°C , the thermogravimetric curve drops sharply, this process is because the amide group in the molecular structure begins to decompose and volatilize; at 360°C to 430°C, the sulfonic acid group in the copolymer molecule begins to decompose rapidly at this stage, and the main chain of the copolymer molecule and The side chains also start to break. The above shows that the thermal stability of the thickening and cutting agent is better.

The synthetic route of the present embodiment is as follows:

Example 6

A method for preparing a high-temperature and high-salt viscosity-increasing and shearing agent for water-based drilling fluids, comprising the following steps:

(1) Preparation of monomeric methacrylic acid-2-(2-ureido-4[1H]-6-methylpyrimidinone)-ethyl ester UPyMA

(1.1) Add 2g of 2-amino-4-hydroxy-6-methylpyrimidine into a 100mL round bottom flask, add 20mL of dimethyl sulfoxide (DMSO), place the flask in an oil bath at 100°C, and stir magnetically Until the solid is completely dissolved to obtain a dimethyl sulfoxide solution of 2-amino-4-hydroxyl-6-methylpyrimidine;

(1.2) 2.4g isocyanoethyl methacrylate is added to the dimethyl sulfoxide solution of 2-amino-4-hydroxyl-6-methylpyrimidine obtained in the above step (1.1) through a constant pressure dropping funnel , the dropping time is 5min. After the dropping is completed, react at 100°C for 15min. The reacted product is naturally cooled to room temperature, and then transferred to a suction filtration device containing a sand core funnel, and a white solid is obtained by suction filtration. The solid was washed with acetone, then suction filtered again, and the suction filtration and washing were repeated 3 times, and finally the obtained solid was dried in a vacuum oven at room temperature for 24 hours to obtain the monomer methacrylic acid-2-(2-ureido-4[1H] -6-methylpyrimidinone)-ethyl ester (UPyMA).

(2) Preparation of temperature-resistant and salt-resistant polymer viscosity-increasing and shearing agent

(2.1) Add 1 g of emulsifier sodium lauryl sulfate and 200 mL of distilled water into a 250 mL beaker, and use a shear emulsifier to shear and emulsify for 30 min at a stirring speed of 1000 r/min to obtain emulsion A;

(2.2) Add 1 g of monomer methacrylic acid-2-(2-ureido-4[1H]-6-methylpyrimidinone)-ethyl ester UPyMA obtained in step (1.2) to the emulsion obtained in step (2.1) In A, use a shear emulsifier to shear and emulsify for 30 minutes at a stirring speed of 1000r/min to obtain micellar solution B;

(2.3) 8g N,N-dimethylacrylamide (DMAA), 8g 2-acrylamido-2-methylpropanesulfonic acid (AMPS), 4g diallyldimethylammonium chloride (DMDAAC) , 0.42g chemical cross-linking agent triallylamine was dissolved in 30mL water, and after fully stirring, monomer solution C was obtained;

(2.4) Mix all the micellar emulsion B obtained in step (2.2) with all the monomer solution C obtained in step (2.3), use a shear emulsifier to emulsify for 30 minutes at a stirring speed of 1000 r/min, and use a mass fraction of 20% NaOH aqueous solution to adjust the pH of the mixed solution to 9 to obtain the mixed reaction solution D;

(2.5) Fully deoxygenate the mixed reaction liquid D in a nitrogen atmosphere, raise the temperature to 55 °C, add 0.42 g of initiator potassium persulfate (KPS), and polymerize at 55 °C for 4 hours. After the reaction, naturally cool to room temperature , that is, the anti-high temperature and anti-high salt viscosity-increasing and shearing agent for water-based drilling fluid.

Comparative example 1

A preparation method of a viscosity-increasing and shearing agent for water-based drilling fluid, comprising the following steps:

(1) 6g N,N-dimethylacrylamide (DMAA), 7g 2-acrylamido-2-methylpropanesulfonic acid (AMPS), 3g diallyldimethylammonium chloride (DMDAAC) , 0.34g of the chemical crosslinking agent triallylamine was dissolved in 230mL of water, and the pH of the mixed solution was adjusted to 9 by using a 20% NaOH aqueous solution by mass fraction to obtain a mixed reaction solution A;

(2) Fully deoxygenate the mixed reaction solution A in a nitrogen atmosphere, raise the temperature to 55°C, add 0.34g of initiator potassium persulfate (KPS), and polymerize at 55°C for 4h. After the reaction, naturally cool to room temperature , that is, a viscosity-increasing and shearing agent for water-based drilling fluid.

No addition of methacrylic acid-2-(2-ureido-4[1H]-6-methylpyrimidinone)-ethyl ester (UPyMA) that can form a quadruple hydrogen bond was added to the thickening and cutting agent of this comparative example. body.

Comparative example 2

A kind of preparation method of viscosity-increasing and shearing agent for water-based drilling fluid is as described in Example 5, the difference is: no crosslinking agent triallylamine is added in the step (2.3), and other conditions are the same as in Example 5 .

Comparative example 3

A preparation method of a viscosity-increasing and shearing agent for water-based drilling fluid, comprising the following steps:

(1) The preparation of monomer methacrylic acid-2-(2-ureido-4[1H]-6-methylpyrimidinone)-ethyl ester UPyMA is the same as that in Example 5.

(2) Preparation of temperature-resistant and salt-resistant polymer viscosity-increasing and shearing agent

(2.1) Add 1 g of emulsifier sodium lauryl sulfate and 200 mL of distilled water into a 250 mL beaker, and use a shear emulsifier to shear and emulsify for 30 min at a stirring speed of 1000 r/min to obtain emulsion A;

(2.2) Add 1 g of monomer methacrylic acid-2-(2-ureido-4[1H]-6-methylpyrimidinone)-ethyl ester UPyMA obtained in step (1) to the emulsion obtained in step (2.1) In A, use a shear emulsifier to shear and emulsify for 30 minutes at a stirring speed of 1000r/min to obtain micellar solution B;

(2.3) Dissolve 7g of 2-acrylamido-2-methylpropanesulfonic acid (AMPS), 3g of diallyldimethylammonium chloride (DMDAAC), and 0.22g of chemical cross-linking agent triallylamine in 30mL water, after fully stirring, obtain monomer solution C;

(2.4) All micellar emulsion B obtained in step (2.2) is mixed with all monomer solution C obtained in step (2.3), and after shear emulsification for 30 min at a stirring speed of 1000 r/min using a shear emulsifier, use 20% mass fraction of NaOH aqueous solution adjusts the pH of the mixed solution to 9 to obtain the mixed reaction solution D;

(2.5) Fully deoxygenate the mixed reaction solution D in a nitrogen atmosphere, raise the temperature to 55°C, add 0.22g of initiator potassium persulfate (KPS), and polymerize at 55°C for 4h. After the reaction, naturally cool to room temperature , that is, a viscosity-increasing and shearing agent for water-based drilling fluid.

No acrylamide monomer was added to the thickening and cutting agent of this comparative example.

Comparative example 4

A preparation method of a viscosity-increasing and shearing agent for water-based drilling fluid, comprising the following steps:

(1) The preparation of monomer methacrylic acid-2-(2-ureido-4[1H]-6-methylpyrimidinone)-ethyl ester UPyMA is the same as that in Example 5.

(2) Preparation of temperature-resistant and salt-resistant polymer viscosity-increasing and shearing agent

(2.1) Add 1 g of emulsifier sodium lauryl sulfate and 200 mL of distilled water into a 250 mL beaker, and use a shear emulsifier to shear and emulsify for 30 min at a stirring speed of 1000 r/min to obtain emulsion A;

(2.2) Add 1 g of monomer methacrylic acid-2-(2-ureido-4[1H]-6-methylpyrimidinone)-ethyl ester UPyMA obtained in step (1) to the emulsion obtained in step (2.1) In A, use a shear emulsifier to shear and emulsify for 30 minutes at a stirring speed of 1000r/min to obtain micellar solution B;

(2.3) Dissolve 6g of N,N-dimethylacrylamide (DMAA), 3g of diallyldimethylammonium chloride (DMDAAC), and 0.2g of chemical cross-linking agent triallylamine in 30mL of water, fully After stirring, a monomer solution C is obtained;

(2.4) Mix all the micellar emulsion B obtained in step (2.2) with all the monomer solution C obtained in step (2.3), use a shear emulsifier to emulsify for 30 minutes at a stirring speed of 1000 r/min, and use a mass fraction of 20% NaOH aqueous solution to adjust the pH of the mixed solution to 9 to obtain the mixed reaction solution D;

(2.5) Fully deoxygenate the mixed reaction liquid D in a nitrogen atmosphere, raise the temperature to 55°C, add 0.2g of initiator potassium persulfate (KPS), and polymerize at 55°C for 4h. After the reaction, cool naturally to room temperature , that is, a viscosity-increasing and shearing agent for water-based drilling fluid.

No temperature-resistant and salt-resistant monomer was added to the viscosity-increasing and cutting-increasing agent in this comparative example.

Comparative example 5

A preparation method of a viscosity-increasing and shearing agent for water-based drilling fluid, comprising the following steps:

(1) The preparation of monomer methacrylic acid-2-(2-ureido-4[1H]-6-methylpyrimidinone)-ethyl ester UPyMA is the same as that in Example 5.

(2) Preparation of temperature-resistant and salt-resistant polymer viscosity-increasing and shearing agent

(2.1) Add 1 g of emulsifier sodium lauryl sulfate and 200 mL of distilled water into a 250 mL beaker, and use a shear emulsifier to shear and emulsify for 30 min at a stirring speed of 1000 r/min to obtain emulsion A;

(2.2) Add 1 g of methacrylic acid-2-(2-ureido-4[1H]-6-methylpyrimidinone)-ethyl ester UPyMA obtained in step (1) to the emulsion A obtained in step (2.1) , use a shear emulsifier to shear and emulsify for 30 minutes at a stirring speed of 1000r/min to obtain micellar solution B;

(2.3) Dissolve 6g N,N-dimethylacrylamide (DMAA), 7g 2-acrylamido-2-methylpropanesulfonic acid (AMPS), 0.28g chemical cross-linking agent triallylamine in 30mL In water, after fully stirring, monomer solution C is obtained;

(2.4) Mix all the micellar emulsion B obtained in step (2.2) with all the monomer solution C obtained in step (2.3), use a shear emulsifier to emulsify for 30 minutes at a stirring speed of 1000 r/min, and use a mass fraction of 20% NaOH aqueous solution to adjust the pH of the mixed solution to 9 to obtain the mixed reaction solution D;

(2.5) Fully deoxygenate the mixed reaction solution D in a nitrogen atmosphere, raise the temperature to 55°C, add 0.28g of initiator potassium persulfate (KPS), and polymerize at 55°C for 4h. After the reaction, cool naturally to room temperature , that is, a viscosity-increasing and shearing agent for water-based drilling fluid.

No cationic monomer was added to the thickening and cutting agent of this comparative example.

Comparative example 6

Tackifier 80A51 was purchased commercially.

Comparative example 7

A preparation method of a viscosity-increasing and shearing agent for water-based drilling fluid is as described in Example 5, except that the crosslinking agent triallylamine added in step (2.3) is replaced by N,N-dimethyl Base acrylamide, other conditions are identical with embodiment 5.

Comparative example 8

A kind of preparation method of viscosity-increasing and shearing agent for water-based drilling fluid is as described in Example 5, the difference is: the monomer methacrylic acid-2-(2-ureido-4[ 1H]-6-methylpyrimidinone)-ethyl ester UPyMA was adjusted to 0.5g, and other conditions were the same as in Example 5.

In this comparative example, the ratio of the monomer methacrylic acid-2-(2-ureido-4[1H]-6-methylpyrimidinone)-ethyl ester UPyMA to the acrylamide monomer is too low.

Comparative example 9

A kind of preparation method of viscosity-increasing and shearing agent for water-based drilling fluid is as described in Example 5, the difference is: the monomer methacrylic acid-2-(2-ureido-4[ 1H]-6-methylpyrimidinone)-ethyl ester UPyMA was adjusted to 2g, and other conditions were the same as in Example 5.

In this comparative example, the ratio of monomer methacrylic acid-2-(2-ureido-4[1H]-6-methylpyrimidinone)-ethyl ester UPyMA to acrylamide monomer is too high.

1. Determination of viscosity average molecular weight of viscosity increasing agent

Referring to the national standard GBT 12005.10-1992 "Polyacrylamide Molecular Weight Determination Viscosity Method", use a fully automatic capillary viscometer to measure the solvent (1.0mol/L NaCl solution) and solution flow time at 30°C, and use the Huggins formula and The Kraemer formula calculates the intrinsic viscosity [η] of the viscosity-increasing agent, and uses the empirical formula Mη=(10000[η]/3.73) ^1.515 to calculate the viscosity-average molecular weight Mη of the viscosity-increasing agent.

2. Effect of viscosifier on rheology and fluid loss performance of base slurry before and after aging

①Preparation of 4wt% bentonite base slurry: add 16g bentonite and 0.56g anhydrous sodium carbonate to 400g water, fully stir at 8000rpm at room temperature for 2h, then seal and stand for hydration at room temperature for 24h;

②Drilling fluid sample configuration: Take 400mL of 4% bentonite base slurry, add 2g (0.5%) samples of Examples 1-6 and Comparative Examples 1-8 respectively, and stir at room temperature for 20min at 6000r/min;

③Brine drilling fluid sample preparation: Take 400mL of 4% bentonite base slurry, add 2g (0.5%) samples of Examples 1-6 and Comparative Examples 1-8 respectively, stir at room temperature at 6000r/min for 20min; then, add 144g (36%) sodium chloride, stir 20min under 4000r/min rotating speed at room temperature;

④ Drilling fluid sample aging treatment: put the above drilling fluid sample in a roller heating furnace, set the aging temperature to 200°C, and the aging time to 16h.

⑤Refer to GB16783.1-2014 "Petroleum and Natural Gas Industry Drilling Fluid Site Test Part I: Water-based Drilling Fluid" to evaluate the rheological and filtration performance of the above-mentioned configuration solution.

3. Performance test results

Table 1 Viscosity-average molecular weight of viscosity-increasing and shearing agent

Table 1 records the viscosity-average molecular weight of the samples of Examples 1-6 and Comparative Examples 1-8: it can be seen that in Examples 1-6, the viscosity-average molecular weight of the sample prepared in Example 5 is relatively large; Quadruple hydrogen bond monomer UPyMA, the free radical polymerization of aqueous solution leads to the largest molecular weight of the viscosity-increasing and shearing agent; comparative example 2 does not introduce the triallylamine chemical crosslinking agent, and the molecular weight of the viscosity-increasing and shearing agent is also relatively large; comparative example 3, 4, and 5 correspond to the lack of DMAA, AMPS, and DMDAAC monomers. It can be seen that the absence of DMAA monomers leads to a decrease in the molecular weight of the viscosity-increasing and shearing agent. This is because DMAA monomers are easy to polymerize and increase the molecular weight of the polymer. , and the lack of DMDAAC monomer leads to an increase in the molecular weight of the viscosity-increasing agent. The average molecular weight is relatively large. The cross-linking agent in Comparative Example 7 was replaced by N,N-dimethylacrylamide, which had little effect on its molecular weight; in Comparative Example 8, the addition of quadruple hydrogen bond monomer UPyMA decreased, and the molecular weight of the viscosity-increasing and shearing agent increased. Large; in Comparative Example 9, the amount of quadruple hydrogen bond monomer UPyMA increases, and the molecular weight of the viscosity increasing and shearing agent decreases.

Table 2 The rheological properties and fluid loss performance data table of the drilling fluid obtained by adding the viscosity-increasing and shearing agent prepared in the examples

It can be seen from the test results in Table 2 that, compared with the base slurry, after adding the viscosity-increasing and shearing agent prepared in Examples 1-6, the apparent viscosity (AV), plastic viscosity (PV), and dynamic shear force of the drilling fluid (YP) has been significantly improved. Even after aging at 200°C, the viscosity increasing and cutting performance of the examples can still be maintained. It can be seen that the viscosity increasing and cutting agents prepared in the examples have excellent high temperature resistance. Among them, after adding the viscosity-increasing and shear-increasing agent of Example 5, the viscosity and shear force of the drilling fluid sample are the largest, the fluid loss is the smallest, and the performance is the most excellent.

Table 3 The rheological properties and fluid loss performance data table of the drilling fluid obtained by adding the viscosifying and shearing agent prepared in the comparative example

As can be seen from Table 3: Comparative Example 1 does not contain quadruple hydrogen bond UPyMA monomer, the molecular weight is larger, the rheological parameters after aging are smaller, and the fluid loss is larger. This is because the structural strength of the polymer network Due to lower; comparative example 2 does not contain the chemical cross-linking agent triallylamine, the chain segment movement ability is not limited at high temperature, resulting in poor temperature resistance; comparative example 3 does not contain DMAA monomer, the molecular weight Relatively low, relatively poor viscosity-increasing performance; comparative example 4 because it does not contain AMPS monomer, the temperature resistance is poor, and there is not enough hydration capacity, so the filtration loss increases; comparative example 5 does not contain DMDAAC monomer , after adding the viscosifying agent, it cannot form a strong interaction with bentonite, and the gel protection ability is weak, resulting in the largest fluid loss; comparative example 6 is a commercially available viscosifying agent 80A51, and the viscosifying and shearing performance after aging is relatively Weaker, poor temperature resistance. The cross-linking agent of comparative example 7 is a two-functionality cross-linking agent, and the network structure of the viscosity-increasing and shearing agent is weak, and the viscosity-increasing and shearing performance after aging is relatively weak, and the temperature resistance is poor. In comparative example 8, the addition amount of the quadruple hydrogen bond monomer is reduced, the grid structure of the viscosity-increasing and shearing agent is weak, and the temperature resistance of the viscosity-increasing and shearing agent is poor. In comparative example 9, the addition amount of the quadruple hydrogen bond monomer increases, and the molecular weight of the viscosity-increasing and shearing agent decreases, resulting in poor viscosity-increasing, shearing, and temperature resistance properties.

Table 4 The rheological properties and fluid loss performance data table of the saturated salt drilling fluid obtained by adding the viscosifying and shearing agent prepared in the examples

From the test results in Table 4, it can be seen that after the base slurry is invaded by salt, the metal sodium ions weaken the electrostatic repulsion between the bentonite particles, compress the diffusion double layer between the bentonite particles, and cause the bentonite particles to aggregate and make pulp The performance deteriorates, and the filtration loss increases sharply. After adding the viscosity-increasing and shear-increasing agent prepared in Examples 1-6, the rheological parameters of the drilling fluid after aging at 200°C have been improved to a certain extent, and the fluid loss is also lower than that of the base slurry. Even after aging at 200°C, the The viscosity-increasing and cutting-lifting performance can still be maintained. It can be seen that the prepared viscosity-increasing and cutting-lifting agent has excellent high temperature resistance. Among them, the fluid loss of the drilling fluid sample added with the viscosity-increasing and shearing agent of Example 5 was the smallest, with a medium pressure filtration loss of 15 mL at room temperature before aging and 28 mL at room temperature after aging, showing the best performance.

Table 5 The rheological properties and fluid loss performance data table of the saturated salt drilling fluid obtained by adding the viscosifying and shearing agent prepared in the comparative example

It can be seen from Table 5 that the viscosity-increasing and cutting-lifting agent prepared in Comparative Example 1 does not contain quadruple hydrogen bond UPyMA monomer, and the structural strength of the polymer grid is low, resulting in poor temperature and salt resistance, and rheological control performance. Weaker, larger fluid loss; the viscosity-increasing and shearing agent prepared in Comparative Example 2 does not contain the chemical crosslinking agent triallylamine, and the linear polymer has a strong chain segment movement ability at high temperature, which intensifies to a certain extent Therefore, the ability of the polymer to resist high temperature and high salt is relatively weak; because the comparative example 3 does not contain DMAA monomer, the molecular weight is relatively low, and the viscosity-increasing performance in the salt water environment is relatively low. Poor; Comparative Example 4 has poor heat and salt resistance because it does not contain AMPS monomer, and there are sufficient anti-salt water hydration groups in the polymer molecule, so the rheological properties and fluid loss control performance are poor; Comparative Example 5 does not contain DMDAAC monomer, the temperature resistance of the thickening and shearing agent is poor, the polymer does not have enough adsorption groups, and the gel protection ability in the saline environment becomes weak, resulting in an increase in its fluid loss; comparative example 6 is a commercially available Viscosifier 80A51 has relatively weak performance of viscosification, shear enhancement and fluid loss reduction in high-temperature and high-salt environment. The cross-linking agent of comparative example 7 is a two-functionality cross-linking agent, the network structure of the viscosity increasing and shearing agent is weak, and the viscosity increasing and shearing performance in the high temperature and high salt environment is relatively poor. In comparative example 8, the addition amount of the quadruple hydrogen bond monomer is reduced, the grid structure of the viscosity-increasing and shearing-lifting agent is weak, and the performance of viscosity-increasing, shearing, and temperature-resistance-salt resistance is poor. In comparative example 9, the addition of quadruple hydrogen bond monomer increases, and the molecular weight of the viscosity-increasing and shearing-lifting agent decreases, resulting in poor performance of viscosity-increasing, shearing, temperature and salt resistance.

In summary, the viscosity-increasing and shear-increasing agent prepared by the present invention still has excellent viscosity-increasing, shear-increasing, and fluid loss reduction performance after aging in a high-temperature (200°C) high-salt (saturated salt) environment, and can enrich the resistance to high-temperature and high-salt water Development of base drilling fluid technology.

Claims (10)

1. A kind of preparation method of anti-high temperature and anti-high salt viscosifying and cutting agent for water-based drilling fluid, comprising steps as follows: (1) Add isocyanoethyl methacrylate to the 2-amino-4-hydroxyl-6-methylpyrimidine solution, and then react; after the reaction is completed, filter, wash, and dry to obtain monomer methacrylic acid -2-(2-ureido-4[1H]-6-methylpyrimidinone)-ethyl ester; (2) Dissolving the emulsifier in water and shearing emulsification to obtain emulsion A; then adding the monomer methacrylic acid-2-(2-ureido-4[1H] obtained in step (1) to the obtained emulsion A -6-methylpyrimidinone)-ethyl ester, after shear emulsification, obtains micellar solution B; (3) adding acrylamide monomers, temperature-resistant and salt-resistant monomers, cationic monomers, and cross-linking agents into water, and stirring evenly to obtain monomer solution C; (4) Mix the micellar emulsion B with the monomer solution C, and after emulsification by shearing, adjust the pH value of the system to obtain the mixed reaction solution D; after passing the obtained mixed reaction solution D through nitrogen to remove oxygen, heat up to the reaction temperature, add triggering Agent, thermally initiates free radical polymerization reaction; after the reaction is completed, lower the temperature to obtain high temperature and high salt viscosity increasing and cutting agent for water-based drilling fluid. 2. according to the preparation method of the described water base drilling fluid of claim 1 anti-high temperature anti-high salt viscosifying and shearing agent, it is characterized in that, described in step (1) 2-amino-4-hydroxyl-6-methyl The pyrimidine solution is obtained by dissolving 2-amino-4-hydroxyl-6-methylpyrimidine in an organic solvent, the organic solvent being dimethylsulfoxide or N,N-dimethylformamide; the 2-amino -The ratio of the mass of 4-hydroxyl-6-methylpyrimidine to the volume of organic solvent is 0.1-0.5g: 2mL, preferably 0.2-0.3g: 2mL; the 2-amino-4-hydroxyl-6-methyl The temperature at which pyrimidine dissolves is 80-150°C, preferably 90-120°C. 3. according to the preparation method of the described water-based drilling fluid of claim 1, it is characterized in that, described in step (1) 2-amino-4-hydroxyl-6-methyl The mass ratio of pyrimidine to isocyanoethyl methacrylate is 1:1-1.5, preferably 1:1.2-1.4; The reaction temperature is 80-150°C, preferably 90-120°C; the reaction time is 1-60min, preferably 10-30min; The washing is 2-6 times with acetone, preferably 3-5 times; the drying is vacuum drying at room temperature for 20-30 hours. 4. according to the preparation method of the described water-based drilling fluid of claim 1, it is characterized in that, the emulsifier described in the step (2) is sodium lauryl sulfate, lauryl sodium One or more combinations of sodium alkylbenzenesulfonate, emulsifier OP-10; the ratio of the quality of the emulsifier to the volume of water is 0.05-0.5g: 20mL, preferably 0.1-0.2g: 20mL; the mass of the monomer methacrylic acid-2-(2-ureido-4[1H]-6-methylpyrimidinone)-ethyl ester and the volume ratio of water are 0.05-0.5g:20mL, preferably 0.1-0.2g: 20mL; The shear emulsification rate is 500-3000r/min, preferably 1000-2000r/min; the shear emulsification time is 10-60min. 5. according to the preparation method of the described water-based drilling fluid of claim 1, it is characterized in that, the acrylamide monomer described in the step (3) is acrylamide, N, N -Dimethacrylamide, isopropylacrylamide; the ratio of the mass of the acrylamide monomer to the volume of water is 0.1-0.2g:1mL; The temperature-resistant and salt-resistant monomer is 2-acrylamide-2-methylpropanesulfonic acid, sodium styrenesulfonate, sodium vinylsulfonate; the cationic monomer is diallyl dimethyl chloride Ammonium, Acryloyloxyethyltrimethylammonium Chloride. 6. according to the preparation method of the described water-based drilling fluid of claim 1, it is characterized in that, described in step (3) acrylamide monomer, temperature-resistant and salt-resistant monomer , The mass ratio of the cationic monomer is 1:0.3-2:0.2-1, preferably 1:0.8-1.5:0.4-0.8; The cross-linking agent is triallylamine or N,N-methylenebisacrylamide; the quality of the cross-linking agent and the total mass of acrylamide monomers, temperature-resistant and salt-resistant monomers, and cationic monomers The ratio is 0.01-0.05:1, preferably 0.02-0.03:1. 7. according to the preparation method of the described water-based drilling fluid of claim 1, it is characterized in that, in the micelle emulsion B described in the step (4), the monomer methacrylic acid-2 The mass ratio of -(2-ureido-4[1H]-6-methylpyrimidinone)-ethyl ester to the acrylamide monomer in the monomer solution C is 1:5-8; The rate of the shear emulsification is 500-3000r/min, preferably 1000-2000r/min; the time of the shear emulsification is 10-60min; The pH value of the mixed reaction liquid D is 3-10, preferably 5-9; the pH of the condition system is an alkaline solution, the alkali is sodium hydroxide, and the mass fraction of the alkaline solution is 10-30%. 8. according to the preparation method of the described water-based drilling fluid of claim 1, it is characterized in that, described in the step (4), initiator is potassium persulfate, ammonium persulfate, even Azobisisobutyronitrile, azobisisobutylamidine hydrochloride; the ratio of the mass of the initiator to the total mass of the acrylamide monomer, the temperature-resistant and salt-resistant monomer, and the cationic monomer is 0.01-0.05:1 , preferably 0.02-0.03:1; The reaction temperature is 50-80°C, preferably 55-70°C; the reaction time is 2-6h, preferably 3-5h. 9. A high-temperature, high-salt, viscosity-increasing and cutting-lifting agent for water-based drilling fluid, characterized in that it is prepared by the preparation method described in any one of claims 1-8. 10. the application of the anti-high temperature and high salt viscosity-increasing and shearing agent for the water-based drilling fluid of claim 9 in the water-based drilling fluid; The concentration of the salt viscosity increasing and cutting agent is 5-10g/L.

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