A kind of fluid loss reducer for drilling fluid and preparation method thereof

Abstract

The present invention relates to the technical field of drilling fluid, and discloses a kind of fluid loss reducer for drilling fluid and its preparation method, the present invention is by adding quaternary ammonium salt modified polyurethane, silane polymer, 2-acrylamide-2-methylpropane sulfonic acid, calcium chloride solution, Tween 20 emulsifier, white oil into a stirrer, stirring, and obtaining the fluid loss reducer for drilling fluid after the end. The polyurethane structure in the quaternary ammonium salt modified polyurethane can form a dense film, which can not only effectively prevent the water in the drilling fluid from entering the formation, thereby protecting the reservoir and improving the drilling efficiency, but also plays a good fluid loss reduction effect. The quaternary ammonium salt group in the fluid loss reducer can effectively inhibit the hydration dispersion of clay through the interaction with clay particles, thereby reducing the occurrence of fluid loss phenomenon; the triazine group and silane group therein can be adsorbed on the surface of clay particles, forming a protective film, preventing flocculation and aggregation between clay particles, thereby maintaining the stability of the drilling fluid, and reducing the occurrence of fluid loss phenomenon.

Description

Technical Field

[0001] The invention relates to the technical field of drilling fluid, in particular to a fluid loss reducer for drilling fluid and a preparation method thereof. Background Art

[0002] Drilling fluid filtration and filter cake formation During the drilling process, drilling fluid filtration is inevitable, and filter cakes can be formed to protect the well wall through filtration. However, excessive drilling fluid filtration can easily cause shale expansion and collapse, resulting in well wall instability. Therefore, how to avoid this phenomenon is the key to solving the problem. For example, patent CN111826136A discloses a drilling fluid and its preparation method. The invention can inhibit the anti-collapse of the well wall and enhance the sealing performance, assist the stability of the formation, and thus effectively reduce the possibility of formation collapse and cracking; however, its filtration effect needs to be improved. Summary of the invention

[0003] 1. Technical issues to be resolved

[0004] In view of the deficiencies in the prior art, the present invention provides a filtrate reducer for drilling fluid and a preparation method thereof, which has excellent filtrate reduction effect, high temperature resistance and salt resistance.

[0005] (II) Technical solution

[0006] To achieve the above object, the present invention provides the following technical scheme: a fluid loss reducer for drilling fluid, comprising the following components by weight: 2-5 parts by weight of quaternary ammonium salt modified polyurethane, 2-4 parts by weight of silane polymer, 5-12 parts by weight of 2-acrylamide-2-methylpropane sulfonic acid, 1-2 parts by weight of calcium chloride solution, 0.8-1.2 parts by weight of Tween 20 emulsifier, and 40-50 parts by weight of white oil.

[0007] Preferably, the preparation method of the quaternary ammonium salt modified polyurethane is:

[0008] (1) Add paraformaldehyde and deionized water into a three-necked flask equipped with a stirrer and a condenser, heat to 75-90°C while stirring, then dropwise add 9-10 mol / L potassium hydroxide solution, after the paraformaldehyde is completely depolymerized, add melamine, and continue the reaction for 1-2 hours. When the solution changes from milky white to colorless and transparent solution, paraformaldehyde-modified melamine is obtained;

[0009] (2) under a nitrogen atmosphere, adding paraformaldehyde-modified melamine and hexamethyldisilazane into a reaction kettle filled with n-butanol solvent, stirring and dispersing, adding chloroplatinic acid catalyst thereto, stirring and reacting at 65-80° C. for 45-55 min, cooling to room temperature after reaction, washing, and obtaining silane-modified melamine;

[0010] (3) adding silane-modified melamine and chloroethanol to N,N-dimethylformamide solvent, stirring and dissolving, heating to 70-90°C for 4-7h, and then distilling under reduced pressure, washing and drying to obtain a quaternary ammonium salt-modified silane chain extender;

[0011] (4) Add 7-15 parts by weight of hexamethylene diisocyanate and 7-10 parts by weight of 1,2-propylene glycol to anhydrous tetrahydrofuran solvent, stir at a constant speed for 30-40 minutes, then add 2-5 parts by weight of a quaternary ammonium salt-modified silane chain extender and 0.1-0.4 parts by weight of a dibutyltin dilaurate catalyst, heat and stir at 50-75° C. for 3-5 hours. After the reaction is completed, cool to room temperature, wash with methanol, and vacuum dry to obtain a quaternary ammonium salt-modified polyurethane.

[0012] Preferably, the mass ratio of paraformaldehyde to melamine in (1) is 1:1.2-1.4.

[0013] Preferably, the mass ratio of the paraformaldehyde-modified melamine, hexamethyldisilazane and chloroplatinic acid catalyst in (2) is 0.8-1:1:0.02-0.03.

[0014] Preferably, the mass ratio of silane-modified melamine to chloroethanol in (3) is 1:2.2-3.

[0015] Preferably, the preparation method of the silane polymer is:

[0016] S1. 10-14 parts by weight of a quaternary ammonium salt-modified silane chain extender and 20-30 parts by weight of acryloyl chloride are added to an N,N-dimethylformamide solvent, stirred and mixed, and 0.1-0.4 parts by weight of a triethylamine catalyst is added thereto, and the temperature is raised to 60-80 ° C for reaction, and after the reaction, rotary distillation, washing, and drying are performed to obtain an olefin-modified quaternary ammonium salt silane;

[0017] S2. Add deionized water solvent to the reactor, stir and add 6-9 parts by weight of olefinic quaternary ammonium salt modified silane, 5-12 parts by weight of pentaerythritol allyl ether, and 7-15 parts by weight of acrylamide in sequence, introduce nitrogen protection, continue to add sodium hydroxide to adjust the pH to 7-8 after dissolution, continue to add 1-3 parts by weight of azobisisobutyronitrile initiator, react at 60-120°C for 5-8h to obtain a silane polymer.

[0018] Preferably, the reaction time in S1 is 7-10 h.

[0019] Preferably, the preparation method of the drilling fluid fluid loss reducer is: adding quaternary ammonium salt-modified polyurethane, silane polymer, 2-acrylamide-2-methylpropane sulfonic acid, calcium chloride solution, Tween 20 emulsifier, and white oil into a stirrer, stirring for 10-16 minutes, and obtaining the drilling fluid fluid loss reducer after stirring.

[0020] 3. Beneficial technical effects

[0021] The invention provides a drilling fluid loss reducer by adding quaternary ammonium salt modified polyurethane, silane polymer, 2-acrylamide-2-methylpropane sulfonic acid, calcium chloride solution, Tween 20 emulsifier and white oil into a stirrer and stirring the mixture.

[0022] The polyurethane structure in the quaternary ammonium salt-modified polyurethane can form a dense film, which can not only effectively prevent the water in the drilling fluid from entering the formation, but also automatically peel off under negative pressure conditions to restore the permeability of the rock, thereby protecting the reservoir and improving the drilling efficiency, and achieving a good filtration reduction effect. The quaternary ammonium salt group in the filtration reduction agent can effectively inhibit the hydration and dispersion of the clay through interaction with the clay particles, which helps to maintain the stability and rheology of the drilling fluid, thereby reducing the occurrence of filtration loss; the triazine group and silane group can be adsorbed on the surface of the clay particles to form a protective film to prevent flocculation and aggregation between the clay particles, thereby maintaining the stability of the drilling fluid and reducing the filtration loss; and after the polyformaldehyde-modified melamine reacts with hexamethyldisilazane, the degree of substitution of the tertiary amine group is increased, and further reacts with chloroethanol to generate a large number of quaternary ammonium salt groups, further reducing the occurrence of filtration loss. DETAILED DESCRIPTION Example 1

[0023] (1) Add paraformaldehyde and deionized water into a three-necked flask equipped with a stirrer and a condenser, heat to 75°C while stirring, then dropwise add 9 mol / L potassium hydroxide solution, and after the paraformaldehyde is completely depolymerized, add melamine, wherein the mass ratio of paraformaldehyde to melamine is 1:1.2, and continue the reaction for 1 hour. When the solution changes from milky white to colorless and transparent solution, paraformaldehyde-modified melamine is obtained;

[0024] (2) Under a nitrogen atmosphere, adding paraformaldehyde-modified melamine and hexamethyldisilazane into a reaction kettle filled with n-butanol solvent, stirring and dispersing, and continuously adding chloroplatinic acid catalyst thereto, wherein the mass ratio of paraformaldehyde-modified melamine, hexamethyldisilazane, and chloroplatinic acid catalyst is 0.8:1:0.02, stirring and reacting at 65° C. for 45 minutes, cooling to room temperature after completion, and washing to obtain silane-modified melamine;

[0025] (3) adding silane-modified melamine and chloroethanol to N,N-dimethylformamide solvent, wherein the mass ratio of silane-modified melamine to chloroethanol is 1:2.2, stirring and dissolving, heating to 70°C for 4 hours, and then distilling under reduced pressure, washing and drying to obtain a quaternary ammonium salt-modified silane chain extender;

[0026] (4) adding 7 parts by weight of hexamethylene diisocyanate and 7 parts by weight of 1,2-propylene glycol to anhydrous tetrahydrofuran solvent, stirring at a constant speed for 30 minutes, then adding 2 parts by weight of a quaternary ammonium salt-modified silane chain extender and 0.1 parts by weight of a dibutyltin dilaurate catalyst, heating and stirring at 50° C. for 3 hours, cooling to room temperature after the reaction is completed, washing with methanol, and vacuum drying to obtain a quaternary ammonium salt-modified polyurethane;

[0027] (5) adding 10 parts by weight of a quaternary ammonium salt modified silane chain extender and 20 parts by weight of acryloyl chloride to an N,N-dimethylformamide solvent, stirring and mixing, and then adding 0.1 parts by weight of a triethylamine catalyst, heating to 60° C. to react for 7 hours, and then rotary distilling, washing, and drying to obtain an olefinated quaternary ammonium salt modified silane;

[0028] (6) Add deionized water solvent to the reactor, stir and add 6 parts by weight of olefinic quaternary ammonium salt modified silane, 5 parts by weight of pentaerythritol allyl ether and 7 parts by weight of acrylamide in sequence, introduce nitrogen protection, add sodium hydroxide to adjust the pH to 7 after dissolution, add 1 part by weight of azobisisobutyronitrile initiator, react at 60° C. for 5 hours to obtain a silane polymer;

[0029] (7) Add 2 parts by weight of quaternary ammonium salt modified polyurethane, 2 parts by weight of silane polymer, 5 parts by weight of 2-acrylamide-2-methylpropanesulfonic acid, 1 part by weight of calcium chloride solution, 0.8 parts by weight of Tween 20 emulsifier, and 40 parts by weight of white oil into a stirrer and stir for 10 minutes to obtain a fluid loss reducer for drilling fluid. Example 2

[0030] (1) Add paraformaldehyde and deionized water into a three-necked flask equipped with a stirrer and a condenser, heat to 90°C while stirring, then dropwise add 10 mol / L potassium hydroxide solution, and after the paraformaldehyde is completely depolymerized, add melamine, wherein the mass ratio of paraformaldehyde to melamine is 1:1.4, and continue the reaction for 2 hours. When the solution changes from milky white to colorless and transparent solution, paraformaldehyde-modified melamine is obtained;

[0031] (2) Under a nitrogen atmosphere, adding paraformaldehyde-modified melamine and hexamethyldisilazane to a reaction kettle filled with n-butanol solvent, stirring and dispersing, and continuously adding chloroplatinic acid catalyst thereto, wherein the mass ratio of paraformaldehyde-modified melamine, hexamethyldisilazane, and chloroplatinic acid catalyst is 1:1:0.03, stirring and reacting at 80° C. for 55 min, cooling to room temperature after completion, and washing to obtain silane-modified melamine;

[0032] (3) adding silane-modified melamine and chloroethanol to N,N-dimethylformamide solvent, wherein the mass ratio of silane-modified melamine to chloroethanol is 1:2.2, stirring and dissolving, heating to 70°C for 4 hours, and then distilling under reduced pressure, washing and drying to obtain a quaternary ammonium salt-modified silane chain extender;

[0033] (4) adding 7 parts by weight of hexamethylene diisocyanate and 7 parts by weight of 1,2-propylene glycol to anhydrous tetrahydrofuran solvent, stirring at a constant speed for 30 minutes, then adding 2 parts by weight of a quaternary ammonium salt-modified silane chain extender and 0.4 parts by weight of a dibutyltin dilaurate catalyst, heating and stirring at 75° C. for 5 hours, cooling to room temperature after the reaction is completed, washing with methanol, and vacuum drying to obtain a quaternary ammonium salt-modified polyurethane;

[0034] (5) adding 14 parts by weight of a quaternary ammonium salt modified silane chain extender and 30 parts by weight of acryloyl chloride to an N,N-dimethylformamide solvent, stirring and mixing, and then adding 0.4 parts by weight of a triethylamine catalyst, heating to 80° C. to react for 10 hours, and then rotary distilling, washing, and drying to obtain an olefinated quaternary ammonium salt modified silane;

[0035] (6) Add deionized water solvent to the reactor, stir and add 9 parts by weight of olefinic quaternary ammonium salt modified silane, 12 parts by weight of pentaerythritol allyl ether, and 15 parts by weight of acrylamide in sequence, introduce nitrogen protection, continue to add sodium hydroxide to adjust the pH to 8 after dissolution, continue to add 3 parts by weight of azobisisobutyronitrile initiator, react at 120° C. for 8 hours to obtain a silane polymer;

[0036] (7) 5 parts by weight of quaternary ammonium salt-modified polyurethane, 4 parts by weight of silane polymer, 12 parts by weight of 2-acrylamide-2-methylpropanesulfonic acid, 2 parts by weight of calcium chloride solution, 1.2 parts by weight of Tween 20 emulsifier, and 50 parts by weight of white oil were added into a stirrer and stirred for 16 minutes to obtain a fluid loss reducer for drilling fluid. Example 3

[0037] (1) Add paraformaldehyde and deionized water into a three-necked flask equipped with a stirrer and a condenser, heat to 82°C while stirring, then dropwise add 9.5 mol / L potassium hydroxide solution, and after the paraformaldehyde is completely depolymerized, add melamine, wherein the mass ratio of paraformaldehyde to melamine is 1:1.3, and continue the reaction for 1.5 hours. When the solution changes from milky white to colorless and transparent solution, paraformaldehyde-modified melamine is obtained;

[0038] (2) Under a nitrogen atmosphere, adding paraformaldehyde-modified melamine and hexamethyldisilazane into a reaction kettle filled with n-butanol solvent, stirring and dispersing, and continuously adding chloroplatinic acid catalyst thereto, wherein the mass ratio of paraformaldehyde-modified melamine, hexamethyldisilazane, and chloroplatinic acid catalyst is 0.9:1:0.025, stirring and reacting at 73° C. for 50 min, cooling to room temperature after completion, and washing to obtain silane-modified melamine;

[0039] (3) adding silane-modified melamine and chloroethanol to N,N-dimethylformamide solvent, wherein the mass ratio of silane-modified melamine to chloroethanol is 1:2.6, stirring and dissolving, heating to 80° C. to react for 5.5 hours, and then distilling under reduced pressure, washing and drying to obtain a quaternary ammonium salt-modified silane chain extender;

[0040] (4) 11 parts by weight of hexamethylene diisocyanate and 8 parts by weight of 1,2-propylene glycol were added to anhydrous tetrahydrofuran solvent, and stirred at a constant speed for 35 minutes. Then, 3.5 parts by weight of a quaternary ammonium salt-modified silane chain extender and 0.25 parts by weight of a dibutyltin dilaurate catalyst were added, and the mixture was heated and stirred at 60° C. for 4 hours. After the reaction was completed, the mixture was cooled to room temperature, washed with methanol, and vacuum dried to obtain a quaternary ammonium salt-modified polyurethane;

[0041] (5) adding 12 parts by weight of a quaternary ammonium salt modified silane chain extender and 25 parts by weight of acryloyl chloride to an N,N-dimethylformamide solvent, stirring and mixing, and then adding 0.3 parts by weight of a triethylamine catalyst, heating to 70° C. to react for 9 hours, and then rotary distilling, washing, and drying to obtain an olefinated quaternary ammonium salt modified silane;

[0042] (6) Add deionized water solvent to the reactor, stir and add 7 parts by weight of olefinic quaternary ammonium salt modified silane, 10 parts by weight of pentaerythritol allyl ether, and 11 parts by weight of acrylamide in sequence, introduce nitrogen protection, continue to add sodium hydroxide to adjust the pH to 7 after dissolution, continue to add 2 parts by weight of azobisisobutyronitrile initiator, react at 90° C. for 6 hours to obtain a silane polymer;

[0043] (7) 4 parts by weight of quaternary ammonium salt modified polyurethane, 3 parts by weight of silane polymer, 8 parts by weight of 2-acrylamide-2-methylpropane sulfonic acid, 1 part by weight of calcium chloride solution, 0.9 parts by weight of Tween 20 emulsifier, and 45 parts by weight of white oil were added into a stirrer and stirred for 13 minutes to obtain a fluid loss reducer for drilling fluid.

[0044] Comparative Example 1

[0045] The difference between this comparative example and Example 3 is that no quaternary ammonium salt is added to modify the polyurethane.

[0046] Comparative Example 2

[0047] The difference between this comparative example and Example 3 is that no silane polymer is added.

[0048] Performance test: The drilling fluid system was prepared according to the following formula: Drilling fluid formula: 300mL No. 5 white oil + 15g organic soil + 15g primary emulsifier (polyisobutylene succinimide) + 5g secondary emulsifier (stearate) + 10g oil-based drilling fluid fluid loss reducer (the fluid loss reducer prepared by Example 1-3 and Comparative Example 1-2) + 10g CaO + 40mL CaCl2 (20% aqueous solution) + 660g weighting agent (barite powder). The apparent viscosity (Ay) and plastic viscosity (PV) of the drilling fluid system were tested, and the test results are shown in Table 1.

[0049] Table 1: Apparent viscosity (Ay) and plastic viscosity (PV) tests of drilling fluid systems.

[0050]

[0051] As can be seen from Table 1, the apparent viscosity and plastic viscosity of Examples 1-3 are basically unchanged compared with Comparative Examples 1-2, indicating that the rate loss reducing agent of the present invention is better.

[0052] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A fluid loss reducer for drilling fluid, characterized in that: The invention comprises the following components by weight: 2-5 parts by weight of quaternary ammonium salt modified polyurethane, 2-4 parts by weight of silane polymer, 5-12 parts by weight of 2-acrylamide-2-methylpropane sulfonic acid, 1-2 parts by weight of calcium chloride solution, 0.8-1.2 parts by weight of Tween 20 emulsifier, and 40-50 parts by weight of white oil; The preparation method of the quaternary ammonium salt modified polyurethane is: (1) Add paraformaldehyde and deionized water into a three-necked flask equipped with a stirrer and a condenser, heat to 75-90°C while stirring, then dropwise add 9-10 mol / L potassium hydroxide solution, after the paraformaldehyde is completely depolymerized, add melamine, and continue the reaction for 1-2 hours. When the solution changes from milky white to colorless and transparent solution, paraformaldehyde-modified melamine is obtained; (2) under a nitrogen atmosphere, adding paraformaldehyde-modified melamine and hexamethyldisilazane into a reaction kettle filled with n-butanol solvent, stirring and dispersing, adding chloroplatinic acid catalyst thereto, stirring and reacting at 65-80° C. for 45-55 min, cooling to room temperature after reaction, washing, and obtaining silane-modified melamine; (3) adding silane-modified melamine and chloroethanol to N,N-dimethylformamide solvent, stirring and dissolving, heating to 70-90°C for 4-7h, and then distilling under reduced pressure, washing and drying to obtain a quaternary ammonium salt-modified silane chain extender; (4) adding 7-15 parts by weight of hexamethylene diisocyanate and 7-10 parts by weight of 1,2-propylene glycol to anhydrous tetrahydrofuran solvent, stirring at a constant speed for 30-40 minutes, then adding 2-5 parts by weight of a quaternary ammonium salt-modified silane chain extender and 0.1-0.4 parts by weight of a dibutyltin dilaurate catalyst, heating and stirring at 50-75° C. for 3-5 hours, cooling to room temperature after the reaction is completed, washing with methanol, and vacuum drying to obtain a quaternary ammonium salt-modified polyurethane; The mass ratio of paraformaldehyde to melamine in (1) is 1:1.2-1.4; The mass ratio of the polyformaldehyde-modified melamine, hexamethyldisilazane and chloroplatinic acid catalyst in (2) is 0.8-1:1:0.02-0.03; The mass ratio of silane-modified melamine to chloroethanol in (3) is 1:2.2-3; The preparation method of the silane polymer is: S1. Add 10-14 parts by weight of the quaternary ammonium salt modified silane chain extender obtained in step (3) above and 20-30 parts by weight of acryloyl chloride to N,N-dimethylformamide solvent, stir and mix, continue to add 0.1-0.4 parts by weight of triethylamine catalyst, heat to 60-80°C for reaction, and after completion, perform rotary distillation, wash, and dry to obtain olefinated quaternary ammonium salt modified silane; S2. Add deionized water solvent to the reactor, stir and sequentially add 6-9 parts by weight of olefinic ammonium salt-modified silane, 5-12 parts by weight of pentaerythritol allyl ether, 7-15 parts by weight of acrylamide, pass nitrogen protection, continue to add sodium hydroxide to adjust the pH to 7-8 after dissolution, continue to add 1-3 parts by weight of azobisisobutyronitrile initiator, react at 60-120 ° C for 5-8h to obtain a silane polymer; The reaction time in S1 is 7-10 hours.

2. A method for preparing a fluid loss reducer for drilling fluid according to claim 1, characterized in that: The preparation method of the drilling fluid fluid loss reducer comprises the following steps: adding quaternary ammonium salt modified polyurethane, silane polymer, 2-acrylamide-2-methylpropane sulfonic acid, calcium chloride solution, Tween 20 emulsifier and white oil into a stirrer, stirring for 10-16 minutes, and obtaining the drilling fluid fluid loss reducer after stirring.

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