Oil well cement fluid loss agent based on AMPS copolymer and preparation method and application thereof

Abstract

The invention relates to an AMPS copolymer-based oil well cement fluid loss agent as well as a preparation method and application thereof. The AMPS copolymer-based oil well cement fluid loss agent comprises a component A and a component B, wherein the component A and the component B are stored separately, and the component A and the component B are mixed during use; the component A is formed by copolymerization of 2-acrylamido-2-methylpropanesulfonic acid, acrylamide and acrylic acid; the component B is formed by fully adsorbing glycerol, ethanol and a high-temperature-resistant cross-linking agent by hollow mesoporous silicon dioxide particles and then naturally airing the hollow mesoporous silicon dioxide particles; wherein the hollow mesoporous silica particles are not thoroughly sintered, so that the hollow mesoporous silica particles can be disintegrated in a stratum environment of 200-230 DEG C, and the high-temperature-resistant cross-linking agent is a cross-linking agent capable of keeping thermal stability at 200-230 DEG C. The invention achieves the following beneficial effects: the MPS-AA-AM copolymer is decomposed at the oil well formation temperature of 200-230 DEG C, so that the MPS-AA-AM copolymer can well adsorb cement slurry particles to form a closed structure where the cement particles are gathered, thereby avoiding water escape.

Description

Technical Field

[0001] The invention relates to the technical field of cement fluid loss reducer, in particular to an oil well cement fluid loss reducer based on AMPS copolymer and a preparation method and application thereof. Background Art

[0002] Fluid loss reducer in oil wells is a chemical additive, which is mainly used to improve the rheological properties of cement slurry in drilling fluid, reduce the water loss of cement slurry during injection, prevent uneven settlement and gap formation when cement ring is formed, so as to ensure the sealing quality of oil well.

[0003] The mechanism of action of fluid loss reducer is to form a protective layer by adsorbing on the surface of cement particles, reduce the electrostatic repulsion between particles, increase the aggregation between particles, and thus reduce the loss of water. At the same time, it can also improve the thixotropy and plasticity of cement slurry, so that it remains stable during pumping and sedimentation.

[0004] At present, the most commonly used method is to copolymerize 2-acrylamido-2-methylpropanesulfonic acid (AMPS), acrylamide (AM) and acrylic acid (AA) in an alkaline environment. Since the sulfonic acid group has good salt resistance, water solubility and thermal stability, and has strong hydration ability, and acrylamide (AM) and acrylic acid (AA) can have good adsorption on cement particles in a high temperature environment, the ability of the fluid loss reducer to control water loss under high temperature conditions is improved.

[0005] However, the copolymer of AMPS-AA-AM, although it has a certain thermal stability due to the presence of sulfonic acid groups; the essence of the polymer copolymer is that acrylic acid and acrylamide are connected by amide bonds, and methylpropane sulfonic acid is covalently bonded to the amino group of acrylamide and the carboxyl group of acrylic acid, but hydrolysis cannot be avoided in high-temperature formations (it can generally withstand temperatures below 200°C, and hydrolysis will begin to occur above 200°C).

[0006] Therefore, this scheme makes certain improvements on the basis of 2-acrylamido-2-methylpropane sulfonic acid (AMPS) and designs an oil well cement fluid loss reducer based on AMPS copolymer. Summary of the invention

[0007] The purpose of the present invention is to overcome the shortcomings of the prior art, provide an oil well cement fluid loss reducer based on AMPS copolymer and a preparation method and application thereof, and solve the problem that the AMPS-AA-AM copolymer in the conventional fluid loss reducer is easily decomposed at a formation temperature above 200°C.

[0008] It should be noted that when the AMPS-AA-AM copolymer is mixed with cement paste, the sulfonic acid group plays a role of spatial isolation on the copolymer - forming a certain small space, and acrylamide (AM) and acrylic acid (AA) have good adsorption on cement particles under high temperature environment - thus playing a sealing role, and the water is stored in the small pores and then sealed, so the water loss effect is not obvious. However, if the AMPS-AA-AM copolymer is hydrolyzed, it loses its sealing ability, which leads to increased water loss.

[0009] The fluid loss reducer of this scheme also has an AMPS-AA-AM copolymer, and the hydrolysis of the AMPS-AA-AM copolymer at a formation temperature above 200° C. is inhibited.

[0010] The object of the present invention is achieved by the following technical solutions: In the first aspect, an oil well cement fluid loss reducer based on AMPS copolymer is provided, comprising component A and component B; wherein component A and component B are stored separately, and component A and component B are mixed when used;

[0011] The component A is formed by copolymerization of 2-acrylamido-2-methylpropanesulfonic acid, acrylamide and acrylic acid;

[0012] The component B is formed by naturally drying the hollow mesoporous silica particles after fully absorbing glycerol, ethanol and a high-temperature resistant cross-linking agent; wherein the hollow mesoporous silica particles are not completely sintered so that they can disintegrate in a formation environment of 200°C-230°C, and the high-temperature resistant cross-linking agent refers to a cross-linking agent that can maintain thermal stability at 200°C-230°C.

[0013] Furthermore, the high temperature resistant crosslinking agent refers to N-acryloyl sulfosuccinimide; when preparing the N-acryloyl sulfosuccinimide, acrylamide and sulfosuccinic anhydride are copolymerized in an organic solvent at a molar ratio of 1:1; then dehydrated; then ethanol, and then recrystallized.

[0014] Furthermore, the hollow mesoporous silica particles are prepared by: mixing tetraethyl orthosilicate with alcohols, adding an alcohol solvent, and then adding an alkaline catalyst to form a stable sol; then aging and drying; and finally sintering, but not completely sintering - allowing it to disintegrate in a formation environment above 200°C.

[0015] Furthermore, when the component B is prepared, the ratio of the hollow silica particles, ethanol, glycerol and the high temperature resistant cross-linking agent is 1: (0.3-0.5): (0.3-0.5): (0.3-0.5) by weight.

[0016] Furthermore, in the component A, 2-acrylamido-2-methylpropanesulfonic acid, acrylamide and acrylic acid are copolymerized in a ratio of 1:1:1 by weight.

[0017] Furthermore, in the oil well cement fluid loss reducer, the ratio of component A to component B is 10:(1-0.5) in parts by weight.

[0018] In a second aspect, a method for preparing an oil well cement fluid loss reducer based on AMPS copolymer is provided, wherein the preparation steps are as follows:

[0019] Prepare component A and component B separately;

[0020] Wherein, when preparing component A, 2-acrylamido-2-methylpropanesulfonic acid, acrylamide and acrylic acid are copolymerized at a certain temperature under the action of a catalyst;

[0021] Among them, when preparing component B: first mix ethanol and propylene glycol, then add a high-temperature resistant cross-linking agent, and stir thoroughly to form a solution; then add hollow mesoporous silica particles into the solution, take out the hollow mesoporous silica particles after sufficient adsorption, and then dry naturally.

[0022] In a third aspect, an application of an oil well cement fluid loss reducer based on AMPS copolymer is provided, which is used as an additive auxiliary material for oil well cement slurry.

[0023] For ease of understanding, the core principles of this solution are explained:

[0024] It should be noted that when preparing oil well cement slurry, a portion of cross-linking agent is added to some cement slurries, but the amount of the cross-linking agent cannot be too much, otherwise it will affect the fluidity of the cement slurry.

[0025] In this scheme: a. In component B of the fluid loss agent, N,N'-methylenebisacrylamide is absorbed by hollow mesoporous silica, so that when preparing cement and pumping cement, N,N'-methylenebisacrylamide will not affect the fluidity of cement slurry. b. Component A (AMPS-AA-AM copolymer) in the fluid loss agent can be lowered in the formation, and can also allow water to be in these intervening spaces by generating spatial separations through sulfonic acid groups, and then can also adsorb cement particles to seal water in the intervening spaces, thereby reducing water loss. c. As the depth of the formation into which the cement slurry is injected increases, when it reaches 60°C, glycerol gradually expands - thereby causing a certain degree of rupture in the hollow mesoporous silica, and then releasing a portion of the high-temperature resistant cross-linking agent, which can be well cross-linked with the AMPS-AA-AM copolymer at this temperature (but will not affect the fluidity of the cement slurry too much). d. When the high temperature formation environment reaches 200℃, the AMPS-AA-AM copolymer hydrolyzes and the sealing ability decreases. At this time, the hollow mesoporous silica will also decompose at high temperature - releasing a large amount of high temperature resistant cross-linking agent, which will cross-link with AMPS-AA-AM to a certain extent at high temperature - thereby preventing the movement of the AMPS-AA-AM copolymer molecular chain, thereby reducing the degree of hydrolysis of the AMPS-AA-AM copolymer at high temperature, so that component A in the entire fluid loss reducer can still play a good water loss reduction effect.

[0026] The present invention has the following advantages:

[0027] When the fluid loss reducer of the present scheme is used as an auxiliary material of cement slurry, as the cement slurry enters deeper formations, when it enters a formation environment of 60°C, the glycerol expands and cracks the mesoporous silica, releasing a portion of the high-temperature resistant cross-linking agent, so that the cement slurry can maintain a good fluid loss reduction effect in a formation of 60°C-200°C (the principle is as described in the previous paragraph and is not repeated here); as the cement slurry is continuously injected, when the cement slurry enters a formation temperature environment of 200°C-230°C, the hollow mesoporous silica disintegrates, thereby releasing a large amount of high-temperature resistant cross-linking agent, thereby inhibiting the decomposition of the MPS-AA-AM copolymer at the oil well formation temperature of 200°C-230°C, so that the MPS-AA-AM copolymer can adsorb the cement slurry particles well-forming a closed structure where the cement particles gather together, thereby avoiding the loss of water. DETAILED DESCRIPTION

[0028] The present invention is further described below, but the protection scope of the present invention is not limited to the following description.

[0029] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] Example 1

[0031] This embodiment discloses an oil well cement fluid loss reducer based on AMPS copolymer, comprising component A and component B, wherein component A and component B are stored separately and are mixed with component B when used;

[0032] Wherein, component A is formed by copolymerization of 2-acrylamido-2-methylpropanesulfonic acid, acrylamide and acrylic acid;

[0033] Component B is formed by naturally drying hollow mesoporous silica particles after fully absorbing glycerol, ethanol and a high temperature resistant cross-linking agent; the hollow mesoporous silica particles are not completely sintered so that they can disintegrate in a formation environment of 200°C-230°C, and the high temperature resistant cross-linking agent refers to a cross-linking agent that can maintain thermal stability at 200°C-230°C;

[0034] It should be noted that the high temperature resistant crosslinking agent refers to N-acryloyl sulfosuccinimide; when N-acryloyl sulfosuccinimide is prepared: acrylamide and sulfosuccinic anhydride are copolymerized in an organic solvent at a molar ratio of 1:1; then dehydrated; then in ethanol, and then recrystallized;

[0035] It should be noted that when preparing hollow mesoporous silica particles: tetraethyl orthosilicate is mixed with alcohols, and then an alcohol solvent is added to the mixture, and then an alkaline catalyst is added to form a stable sol; then the sol is aged and dried; and finally, the sol is sintered, but not completely sintered - it is allowed to disintegrate in a formation environment above 200°C.

[0036] Specifically, the preparation steps of the oil well cement fluid loss reducer based on AMPS copolymer are disclosed as follows:

[0037] Prepare component A and component B separately;

[0038] Among them, when preparing component B: by weight, first mix 0.3 parts of ethanol and 0.3 parts of propylene glycol, then add 0.3 parts of high temperature resistant crosslinking agent, stir well to form a solution; then add 1 part of hollow mesoporous silica particles to the solution, take out the hollow mesoporous silica particles after full adsorption, and then dry naturally - a large amount of ethanol evaporates during drying

[0039] Wherein, when component A is prepared, [(1+0.3+0.3+0.3)×20]×0.3 parts of 2-acrylamido-2-methylpropanesulfonic acid, [(1+0.3+0.3+0.3)×20]×0.3 parts of acrylamide, and [(1+0.3+0.3+0.3)×20]×0.3 parts of acrylic acid are copolymerized at a temperature of 70°C-100°C (as long as it is within this temperature range) in the presence of a catalyst (i.e., a conventional preparation method is adopted, which is not described here).

[0040] Example 2

[0041] This example discloses an oil well cement fluid loss reducer based on AMPS copolymer, and each substance is the same as that in Example 1.

[0042] This embodiment also discloses a method for preparing an oil well cement fluid loss reducer based on AMPS copolymer, the preparation steps being:

[0043] Prepare component A and component B separately;

[0044] Among them, when preparing component B: by weight, first mix 0.4 parts of ethanol and 0.4 parts of propylene glycol, then add 0.4 parts of high temperature resistant crosslinking agent, stir well to form a solution; then add 1 part of hollow mesoporous silica particles to the solution, take out the hollow mesoporous silica particles after full adsorption, and then dry naturally - a large amount of ethanol evaporates during drying

[0045] Wherein, when component A is prepared, [(1+0.4+0.4+0.4)×10÷7]×0.3 parts of 2-acrylamido-2-methylpropanesulfonic acid, [(1+0.4+0.4+0.4)×10÷7]×0.3 parts of acrylamide, and [(1+0.4+0.4+0.4)×10÷7]×0.3 parts of acrylic acid are copolymerized at a temperature of 70°C-100°C (as long as it is within this temperature range) in the presence of a catalyst (i.e., a conventional preparation method is adopted, which will not be described in detail here).

[0046] Example 3

[0047] This example discloses an oil well cement fluid loss reducer based on AMPS copolymer, and each substance is the same as that in Example 1.

[0048] This embodiment also discloses a method for preparing an oil well cement fluid loss reducer based on AMPS copolymer, the preparation steps being:

[0049] Prepare component A and component B separately;

[0050] Among them, when preparing component B: by weight, first mix 0.5 parts of ethanol and 0.5 parts of propylene glycol, then add 0.5 parts of high temperature resistant crosslinking agent, stir well to form a solution; then add 1 part of hollow mesoporous silica particles to the solution, take out the hollow mesoporous silica particles after full adsorption, and then dry naturally - a large amount of ethanol evaporates during drying

[0051] Wherein, when component A is prepared, [(1+0.5+0.5+0.5)×10]×0.3 parts of 2-acrylamido-2-methylpropanesulfonic acid, [(1+0.5+0.5+0.5)×10]×0.3 parts of acrylamide, and [(1+0.5+0.5+0.5)×10]×0.3 parts of acrylic acid are copolymerized at a temperature of 70°C-100°C (as long as it is within this temperature range) in the presence of a catalyst (i.e., a conventional preparation method is adopted, which is not described here).

[0052] Test Example 1

[0053] Comparative Example 1, except for component B in Example 1, all contents are the same as those in Example 1;

[0054] Comparative Example 2, except for component B in Example 2, all contents are the same as those in Example 2;

[0055] Comparative Example 3, except that component B in Example 3 is removed, all contents are the same as those in Example 3.

[0056] Different mass ratios of fluid loss reducers were added to Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, and Comparative Example 3 according to different temperature points. The mass ratios of the fluid loss reducers added to the oilfield cementing cement slurry at each temperature were as follows: 2% of the fluid loss reducer was added to the oilfield cementing cement at 100°C, 3.2% of the fluid loss reducer was added to the oilfield cementing cement at 150°C, 4% of the fluid loss reducer was added to the oilfield cementing cement at 180°C, 5.5% of the fluid loss reducer was added to the oilfield cementing cement at 200°C, 6.5% of the fluid loss reducer was added to the oilfield cementing cement at 210°C, 7.5% of the fluid loss reducer was added to the oilfield cementing cement at 220°C, and 8.6% of the fluid loss reducer was added to the oilfield cementing cement at 230°C. According to "SY / T 5504.2-2013 Evaluation Methods for Oil Well Cement Admixtures Part 2: Fluid Loss Reducers", the temperature and water loss test results are shown in Tables 1 to 6 below.

[0057] Table 1 is a table showing the temperature and water loss test results of Example 1

[0058]

[0059] Table 2 is the temperature and water loss test table of Example 2

[0060]

[0061] Table 3 is the temperature and water loss test table of Example 3

[0062]

[0063] Table 4 is the temperature and water loss test table of comparative example 1

[0064]

[0065] Table 5 is the temperature and water loss test table of comparative example 2

[0066]

[0067] Table 6 is the temperature and water loss test table of comparative example 3

[0068]

[0069] It can be seen from Tables 1 to 6 that when the temperature is increased from 180°C to 200°C, the water loss increases significantly, indicating that AMPS-AA-AM undergoes severe hydrolysis.

[0070] Similarly, it can be seen from Tables 1 to 6 that in the present solution, when component B is added (after the hollow mesoporous silica particles contain glycerol and a high temperature resistant crosslinking agent), the dehydration effect is improved within the temperature range of 100°C-230°C. Among them, the improvement is achieved at 100°C-180°C, indicating that glycerol plays a role. Among them, the improvement is obvious during the period of 200°C-230°C, indicating that at this time, after the hollow mesoporous silica is decomposed, the corresponding high temperature resistant crosslinking agent begins to play a crosslinking role.

[0071] The above embodiments only express preferred implementation modes, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention.

Claims

1. An oil well cement fluid loss reducer based on AMPS copolymer, characterized in that: It comprises component A and component B, wherein component A and component B are stored separately and are mixed with component B when used; The component A is formed by copolymerization of 2-acrylamido-2-methylpropanesulfonic acid, acrylamide and acrylic acid; The component B is formed by naturally drying the hollow mesoporous silica particles after fully absorbing glycerol, ethanol and a high-temperature resistant cross-linking agent; wherein the hollow mesoporous silica particles are not completely sintered so that they can disintegrate in a formation environment of 200°C-230°C, and the high-temperature resistant cross-linking agent refers to a cross-linking agent that can maintain thermal stability at 200°C-230°C.

2. The oil well cement fluid loss reducer based on AMPS copolymer according to claim 1, characterized in that: The high temperature resistant cross-linking agent is N-acryloyl sulfosuccinimide; The N-acryloyl sulfosuccinimide is prepared by copolymerizing acrylamide and sulfosuccinic anhydride in an organic solvent at a molar ratio of 1:1; then dehydrating; then re-introducing into ethanol, and then recrystallizing.

3. The oil well cement fluid loss reducer based on AMPS copolymer according to claim 2, characterized in that: The hollow mesoporous silica particles are prepared by mixing tetraethyl orthosilicate with alcohols, adding an alcohol solvent, and then adding an alkaline catalyst to form a stable sol; then aging and drying; and finally sintering, but not completely sintering - allowing it to disintegrate in a formation environment above 200°C.

4. The oil well cement fluid loss reducer based on AMPS copolymer according to claim 3, characterized in that: When the component B is prepared, the ratio of the hollow silica particles, ethanol, glycerol and the high temperature resistant cross-linking agent is 1: (0.3-0.5): (0.3-0.5): (0.3-0.5) by weight.

5. The oil well cement fluid loss reducer based on AMPS copolymer according to claim 4, characterized in that: In the component A, 2-acrylamido-2-methylpropanesulfonic acid, acrylamide and acrylic acid are copolymerized in a ratio of 1:1:1 by weight.

6. The oil well cement fluid loss reducer based on AMPS copolymer according to claim 4, characterized in that: In the oil well cement fluid loss reducer, the weight ratio of component A to component B is 10:(1-0.5).

7. The method for preparing the oil well cement fluid loss reducer based on AMPS copolymer according to any one of claims 1 to 6, characterized in that: The preparation steps are: Prepare component A and component B separately; Wherein, when preparing component A, 2-acrylamido-2-methylpropanesulfonic acid, acrylamide and acrylic acid are copolymerized at a certain temperature under the action of a catalyst; Among them, when preparing component B: first mix ethanol and propylene glycol, then add a high-temperature resistant cross-linking agent, and stir thoroughly to form a solution; then add hollow mesoporous silica particles into the solution, take out the hollow mesoporous silica particles after sufficient adsorption, and then dry naturally.

8. The use of the oil well cement fluid loss reducer based on AMPS copolymer according to any one of claims 1 to 7, characterized in that: Used as an additive in oil well cement slurry.

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