A high-temperature anti-channeling fluid loss agent and preparation method thereof

Abstract

The present invention provides a high-temperature anti-channeling fluid loss agent and a preparation method thereof. The components of the high-temperature anti-channeling fluid loss agent include the following raw materials in parts by weight: 60-90 parts of a comonomer, 1-2 parts of an initiator, and 90-110 parts of deionized water. In the present invention, the copolymer molecule contains a relatively large amount of chalcone, which enables it to have a strong ability to chelate metal ions, and generates a stable water-soluble cyclic structure through reaction and chelation, which can effectively delay the cement hydration process and prolong the cement slurry thickening time. The introduction of acrylamide improves the static gel strength of the cement slurry, and the introduction of dimethyl acrylamide into the polymer instead of a part of acrylamide improves the high temperature resistance of the fluid loss agent. 2-2-Acrylamide methylpropane sulfonic acid and N-vinyl pyrrolidone further improve the high temperature resistance and anti-channeling performance of the fluid loss agent.

Description

Technical Field

[0001] The invention relates to the technical field of fluid loss reducers, and in particular to a high-temperature anti-channeling fluid loss reducer and a preparation method thereof. Background Art

[0002] Fluid loss additive products can be divided into: granular materials and water-soluble polymers and organic materials. Among granular materials, latex has become a research hotspot at home and abroad due to its good advantages of reducing filtration, preventing gas channeling, and toughening. Most fluid loss additive products are water-soluble polymers and organic materials, which can be divided into modified natural products and synthetic polymers.

[0003] Since the implementation of cementing operations, gas channeling has always been a problem that plagues cementing. The annular gas channeling after cementing not only affects the isolation of gas layers, but also is not conducive to the safe exploration and development of oil and gas fields. Once gas channeling occurs, it will affect the production efficiency of the oil well and destroy the interlayer structure at the least, or even lead to the scrapping of the oil well, affecting the safety of production and causing huge economic losses. Therefore, it is important to improve the anti-gas channeling ability of cement slurry.

[0004] The fluid loss reducers obtained in traditional technologies usually have defects such as poor fluid loss reduction performance, poor anti-gas channeling effect, and poor adaptability, so it is necessary to make corresponding improvements to the relevant performance. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a high-temperature anti-channeling fluid loss reducer and a preparation method thereof. The high-temperature anti-channeling fluid loss reducer has the advantages of convenient synthesis, excellent fluid loss reduction performance, good gas channeling prevention effect, strong adaptability, and can effectively improve the cementing effect of oil and gas wells.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0007] A high-temperature anti-channeling fluid loss reducer comprises the following raw materials in parts by weight: 60-90 parts of comonomer, 1-2 parts of initiator and 90-110 parts of deionized water.

[0008] Preferably, the copolymerizable monomers include nonionic monomers and anionic monomers. The nonionic monomers include acrylamide, N-vinyl pyrrolidone and dimethyl acrylamide. The anionic monomers include sulfonate monomers and carboxylate monomers.

[0009] Preferably, the components of the fluid loss additive include the following raw materials in parts by weight: 25-35 parts of 2-acrylamide-2-methylpropane sulfonic acid, 15-25 parts of acrylamide, 10-15 parts of dimethylacrylamide, 2-10 parts of carboxylate monomer, 1-5 parts of N-vinyl pyrrolidone, 1-2 parts of initiator, and 90-110 parts of deionized water.

[0010] Preferably, the components of the fluid loss additive include the following raw materials in parts by weight: 30 parts of 2-acrylamide-2-methylpropane sulfonic acid, 20 parts of acrylamide, 12 parts of dimethylacrylamide, 6 parts of carboxylate monomer, 3 parts of N-vinyl pyrrolidone, 1.5 parts of initiator, and 100 parts of deionized water.

[0011] Preferably, the carboxylate monomer consists of fumaric acid and itaconic acid in a mass ratio of 1:1.

[0012] Preferably, the initiator is hydrogen peroxide-ammonium ferrous sulfate.

[0013] The preparation method of the high-temperature anti-channeling fluid loss agent comprises the following steps:

[0014] S1. Add itaconic acid and 2 / 5 of deionized water to a four-necked flask, adjust the pH to 3.5-4, stir and dissolve in a constant temperature water bath at 60°C, introduce nitrogen to deoxygenate, add 2-acrylamide-2-methylpropanesulfonic acid and N-vinylpyrrolidone after 25-30 minutes, and add 1 / 3 of initiator at the same time, react at 60°C for 2-3 hours, and cool to room temperature to obtain copolymer A;

[0015] S2. Add acrylamide, dimethylacrylamide, fumaric acid, the remaining initiator and the remaining deionized water into a wide-mouth bottle, stir for 2-3 hours under a constant temperature water bath, adjust the pH to 7-8, and obtain a high-temperature anti-channeling fluid loss agent.

[0016] Preferably, the temperature of the constant temperature water bath in step S2 is 60°C.

[0017] The beneficial effects of the present invention are:

[0018] Acrylamide, N-vinyl pyrrolidone, and dimethylacrylamide are non-ionic monomers of fluid loss reducers, and carboxylate monomers and sulfonate monomers are anionic monomers. Among them, the fumaric acid molecule has two adjacent carboxyl groups, and there is a double bond between the two carboxyl groups of fumaric acid. The itaconic acid molecule has two carboxyl groups and is adjacent to each other, so itaconic acid can better adsorb on the surface of cement particles to hinder cement hydration and show a stronger retarding effect. At the same time, due to the protective effect of the sulfonate group in the 2-acrylamide-2-methylpropanesulfonic acid molecule, the copolymer synthesized by itaconic acid / 2-acrylamide-2-methylpropanesulfonic acid is more stable in high temperature and saline-alkali environment.

[0019] The copolymer molecules contain more antelope groups, which give them a strong ability to chelate metal ions. Through reaction and chelation, they produce a stable water-soluble ring structure, which can effectively delay the cement hydration process and prolong the thickening time of cement slurry.

[0020] In the present application, the introduction of acrylamide improves the static gel strength of cement slurry, and dimethyl acrylamide replaces a part of acrylamide and is introduced into the polymer to improve the high temperature resistance of the fluid loss reducer. 2-2-Acrylamidomethylpropanesulfonic acid and N-vinyl pyrrolidone further improve the high temperature resistance and anti-channeling performance of the fluid loss reducer. DETAILED DESCRIPTION

[0021] 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 in combination with the embodiments of the present invention. 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.

[0022] A high-temperature anti-channeling fluid loss agent is prepared from the following raw materials in proportion: 25-35 parts of 2-acrylamide-2-methylpropanesulfonic acid, 15-25 parts of acrylamide, 10-15 parts of dimethylacrylamide, 1-5 parts of fumaric acid, 1-5 parts of itaconic acid, 1-5 parts of N-vinyl pyrrolidone, 1-2 parts of hydrogen peroxide-ammonium ferrous sulfate, and 90-110 parts of deionized water.

[0023] A method for preparing a high-temperature anti-channeling fluid loss agent comprises the following steps:

[0024] S1. Add itaconic acid and 2 / 5 of deionized water to a four-necked flask, adjust the pH to 3.5-4, stir and dissolve in a constant temperature water bath at 60°C, introduce nitrogen to deoxygenate, add 2-acrylamide-2-methylpropanesulfonic acid and N-vinylpyrrolidone after 25-30 minutes, and add 1 / 3 of initiator at the same time, react at 60°C for 2-3 hours, and cool to room temperature to obtain copolymer A;

[0025] S2. Add acrylamide, dimethylacrylamide, fumaric acid, the remaining initiator and the remaining deionized water into a wide-mouth bottle, stir for 2-3 hours in a constant temperature water bath at 60°C, adjust the pH to 7-8, and obtain a high-temperature anti-channeling fluid loss agent.

[0026] Embodiment 1:

[0027] A high-temperature anti-channeling fluid loss agent, wherein the proportions of the raw material components in the fluid loss agent are as follows:

[0028] Table 1 Ratio of each raw material component in Example 1

[0029]

[0030] Embodiment 2:

[0031] A high-temperature anti-channeling fluid loss agent, wherein the proportions of the raw material components in the fluid loss agent are as follows:

[0032] Table 2 Ratio of each raw material component in Example 2

[0033]

[0034]

[0035] Embodiment 3:

[0036] A high-temperature anti-channeling fluid loss agent, wherein the proportions of the raw material components in the fluid loss agent are as follows:

[0037] Table 3 Ratio of each raw material component in Example 3

[0038]

[0039] Embodiment 4:

[0040] A high-temperature anti-channeling fluid loss agent, wherein the proportions of the raw material components in the fluid loss agent are as follows:

[0041] Table 4 Ratios of the raw material components in Example 4

[0042]

[0043]

[0044] Comparative Example 1:

[0045] A high-temperature anti-channeling fluid loss agent, the high-temperature anti-channeling fluid loss agent differs from Example 3 only in that fumaric acid is not added.

[0046] Comparative Example 2:

[0047] A high-temperature anti-channeling fluid loss agent, the high-temperature anti-channeling fluid loss agent differs from Example 3 only in that itaconic acid is not added.

[0048] Comparative Example 3:

[0049] A high-temperature anti-channeling fluid loss agent, the high-temperature anti-channeling fluid loss agent differs from Example 3 only in that no acrylamide is added.

[0050] Comparative Example 4:

[0051] A high-temperature anti-channeling fluid loss agent, the high-temperature anti-channeling fluid loss agent differs from Example 3 only in that: N-vinyl pyrrolidone is not added.

[0052] Comparative Example 5:

[0053] A high-temperature anti-channeling fluid loss agent, the high-temperature anti-channeling fluid loss agent differs from Example 3 only in that dimethylacrylamide is not added.

[0054] Comparative Example 6:

[0055] A high-temperature anti-channeling fluid loss agent, the high-temperature anti-channeling fluid loss agent is different from Example 3 only in that 2-acrylamide-2-methylpropanesulfonic acid is not added.

[0056] Comparative Example 7:

[0057] A high-temperature anti-channeling fluid loss agent, the difference between the high-temperature anti-channeling fluid loss agent and Example 3 is that: in step S1, the pH is 1-2.

[0058] Comparative Example 8:

[0059] A high-temperature anti-channeling fluid loss agent, the difference between the high-temperature anti-channeling fluid loss agent and Example 3 is that: in step S1, the pH is 2-3.

[0060] Comparative Example 9:

[0061] A high-temperature anti-channeling fluid loss agent, the difference between the high-temperature anti-channeling fluid loss agent and Example 3 is that: in step S1, the pH is 5-6.

[0062] Comparative Example 10:

[0063] A high-temperature anti-channeling fluid loss agent, the difference between the high-temperature anti-channeling fluid loss agent and Example 3 is that: in step S1, the pH is 7-8.

[0064] Comparative Example 11:

[0065] A high-temperature anti-channeling fluid loss agent, the difference between the high-temperature anti-channeling fluid loss agent and Example 3 is only that: in step S1, the pH is 9-10.

[0066] Comparative Example 12:

[0067] A high-temperature anti-channeling fluid loss agent, the high-temperature anti-channeling fluid loss agent differs from Example 3 only in that nitrogen is not introduced for deoxygenation.

[0068] Comparative Example 13:

[0069] A high-temperature anti-channeling fluid loss agent, the difference between the high-temperature anti-channeling fluid loss agent and Example 3 is that the temperature of the constant temperature water bath in step S2 is 50°C.

[0070] Comparative Example 14:

[0071] A high-temperature anti-channeling fluid loss agent, the difference between the high-temperature anti-channeling fluid loss agent and Example 3 is that the temperature of the constant temperature water bath in step S2 is 55°C.

[0072] Comparative Example 15:

[0073] A high-temperature anti-channeling fluid loss agent, the difference between the high-temperature anti-channeling fluid loss agent and Example 3 is that the temperature of the constant temperature water bath in step S2 is 65°C.

[0074] Comparative Example 16:

[0075] A high-temperature anti-channeling fluid loss agent, the difference between the high-temperature anti-channeling fluid loss agent and Example 3 is that the temperature of the constant temperature water bath in step S2 is 70°C.

[0076] The fluid loss additives obtained in the above Examples 1-4 and Comparative Examples 1-16 were subjected to performance tests to measure the comprehensive performance of the fluid loss additives. The results are shown in Table 5.

[0077] Table 5 Performance parameters of the fluid loss additives obtained in Examples 1-4 and Comparative Examples 1-16

[0078]

[0079]

[0080] From Table 5, we can see that:

[0081] The change of the weight of each component in the high-temperature anti-channeling fluid loss agent has only a small effect on the water loss and thickening time. The lack of a component in fumaric acid, itaconic acid, acrylamide, N-vinyl pyrrolidone, dimethyl acrylamide, and 2-acrylamide-2-methylpropanesulfonic acid will directly reduce the thickening time of the fluid loss agent. The change of pH and the change of the constant temperature water bath temperature have little effect on the thickening time of the fluid loss agent. Failure to pass nitrogen gas for deoxygenation will reduce the thickening time of the fluid loss agent.

[0082] In summary, acrylamide, N-vinyl pyrrolidone, and dimethyl acrylamide are non-ionic monomers of fluid loss reducers, and carboxylate monomers and sulfonate monomers are anionic monomers. Among them, the fumaric acid molecule has two adjacent carboxyl groups, and there is a double bond between the two carboxyl groups of fumaric acid. The itaconic acid molecule has two carboxyl groups and is adjacent to each other, so itaconic acid can better adsorb on the surface of cement particles to hinder cement hydration and show a stronger retarding effect. At the same time, due to the protective effect of the sulfonate group in the 2-acrylamide-2-methylpropanesulfonic acid molecule, the copolymer synthesized by itaconic acid / 2-acrylamide-2-methylpropanesulfonic acid is more stable in high temperature and saline-alkali environment.

[0083] The copolymer molecules contain more antelope groups, which give them a strong ability to chelate metal ions. Through reaction and chelation, they produce a stable water-soluble ring structure, which can effectively delay the cement hydration process and prolong the thickening time of cement slurry.

[0084] In the present application, the introduction of acrylamide improves the static gel strength of cement slurry, and dimethyl acrylamide replaces a part of acrylamide and is introduced into the polymer to improve the high temperature resistance of the fluid loss reducer. 2-2-Acrylamidomethylpropanesulfonic acid and N-vinyl pyrrolidone further improve the high temperature resistance and anti-channeling performance of the fluid loss reducer.

[0085] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high temperature anti-channeling fluid loss agent, characterized in that: The fluid loss reducer comprises the following raw materials in parts by weight: 25-35 parts of 2-acrylamide-2-methylpropanesulfonic acid, 15-25 parts of acrylamide, 10-15 parts of dimethylacrylamide, 2-10 parts of carboxylic acid monomer, 1-5 parts of N-vinyl pyrrolidone, 1-2 parts of initiator, and 90-110 parts of deionized water; The carboxylic acid monomer is composed of fumaric acid and itaconic acid in a mass ratio of 1:1; The preparation method of the high-temperature anti-channeling fluid loss agent comprises the following steps: S1. Add itaconic acid and 2 / 5 of deionized water to a four-necked flask, adjust the pH to 3.5-4, stir and dissolve in a constant temperature water bath at 60°C, introduce nitrogen to deoxygenate, add 2-acrylamide-2-methylpropanesulfonic acid and N-vinylpyrrolidone after 25-30 minutes, and add 1 / 3 of initiator at the same time, react at 60°C for 2-3 hours, and cool to room temperature to obtain copolymer A; S2. Add acrylamide, dimethylacrylamide, fumaric acid, the remaining initiator and the remaining deionized water into a wide-mouth bottle, stir for 2-3 hours in a constant temperature water bath at 60°C, adjust the pH to 7-8, and obtain a high-temperature anti-channeling fluid loss agent.

2. The high temperature anti-channeling fluid loss agent according to claim 1, characterized in that: The components of the fluid loss reducer include the following raw materials in parts by weight: 30 parts of 2-acrylamide-2-methylpropane sulfonic acid, 20 parts of acrylamide, 12 parts of dimethylacrylamide, 6 parts of carboxylic acid monomer, 3 parts of N-vinyl pyrrolidone, 1.5 parts of initiator and 100 parts of deionized water.

3. The high temperature anti-channeling fluid loss agent according to claim 1, characterized in that: The initiator is hydrogen peroxide-ammonium ferrous sulfate.

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