CN114316926B - Chitosan oil field clay stabilizer based on Mannich reaction and preparation method thereof - Google Patents

Abstract

The invention provides a chitosan oilfield clay stabilizer based on the Mannich reaction and a preparation method thereof. The chitosan, an acid component and an aldehyde component are mixed and heated to obtain a mixed solution, and the pH value of the mixed solution is adjusted to be acidic. to obtain a solid product; the solid product is washed and then freeze-dried to obtain a modified chitosan clay stabilizer. The present invention uses chitosan as amine component, mixes chitosan with acid component and aldehyde component to carry out Mannich reaction, realizes the modification of chitosan cation, and introduces anion group containing acid group into its structure , to obtain a clay stabilizer with temperature and salt resistance, the clay stabilizer can be strongly adsorbed to the clay surface, not easy to decompose, has a long validity period, and the temperature resistance can reach 250 ° C, and the anti-swelling rate is greater than 90%.

Description

A chitosan oilfield clay stabilizer based on Mannich reaction and its preparation method

technical field

The invention belongs to the technical field of oilfield development, in particular to a chitosan oilfield clay stabilizer based on Mannich reaction and a preparation method thereof.

Background technique

Clay minerals widely exist in oil layers, and most oil reservoirs are located in sandstone reservoirs, which also commonly contain clay minerals. With the in-depth development of oil reservoirs, in drilling, well completion, perforation, acidizing, fracturing, water injection, oil recovery and other processes, the contact of foreign additives with clay minerals in oil layers may destroy the original physical and chemical balance in the formation, making Clay minerals disperse and migrate, block the pore structure of the formation, reduce the permeability of the formation, and eventually damage the oil layer. Secondly, in the process of petroleum exploration and development, the hydration expansion of clay minerals has a greater impact on the quality of the oil layer, which will cause problems such as low permeability, high temperature, and high salinity in the oil reservoir, thus causing serious damage to the reservoir. damage, and lead to a decrease in oil well production or even shut down.

Clay stabilizer is a chemical that can be adsorbed on the surface of clay to avoid damage to oil and gas layers caused by hydration expansion and dispersion transfer of water-sensitive minerals, and can effectively prevent damage to oil layers during the mining process. Clay stabilizers are mainly divided into inorganic salt and inorganic alkali clay stabilizers, inorganic multi-core polymer clay stabilizers, cationic surfactants and organic cationic polymer clay stabilizers. The organic cationic polymer clay stabilizer has the advantages of wide application range, good stabilizing effect, long effective time and strong washing ability against acid, alkali, oil and water. At present, the research and development of such materials mainly include the use of various natural polymers, such as starch, lignin, glue, gutter oil, polymerized sugar, cellulose, etc. (Drilling and Production Technology, 2015, 38: 98; Forest Products Chemistry and Industry, 1998, 3:29; Drilling Fluid and Completion Fluid, 2004, 6:47; Chemical Research and Application, 2019, 2:347; Polysaccharide Drilling Fluid Application Process Optimization and Mechanism Exploration, Xi’an Petroleum University, 2014; Cellulose Science and Technology, 1995, 4:20), carry out cationic modification through etherification reaction, esterification reaction, etc., and the raw materials used include imidazole, 2-(methylamino)chloromethane hydrochloride, etc. The molecular structure of some raw materials or products contains benzene rings, chlorophenols, thiophenes and other toxic and difficult-to-degrade groups, which make clay stabilizers highly toxic, pollute the environment, and cause damage to the reservoir; secondly, some processes The experimental reaction conditions need to be strictly controlled, the process is cumbersome, and the production efficiency is low. Moreover, some clay stabilizers are not suitable for high temperature environment, which limits their application in stabilizing clay.

Contents of the invention

In order to solve the problems of high toxicity, environmental pollution, complicated process and low production efficiency of preparing clay stabilizers that exist in the prior art, the invention provides a chitosan oilfield clay stabilizer based on Mannich reaction and a preparation method thereof. Chitosan is an amine component, and chitosan is mixed with an acid component and an aldehyde component to achieve cationic modification of chitosan, and an anionic group containing an acid radical is introduced into its structure to obtain a product with temperature and salt resistance. Strong clay stabilizer.

For achieving the above object, the present invention provides following technical scheme: a kind of chitosan oil field clay stabilizer based on Mannich reaction, concrete steps are as follows:

S1 mixes chitosan, acid component and aldehyde component, heats to obtain a mixed solution, adjusts the pH value of the mixed solution to acidity, and obtains a solid product;

In S2, the solid product is washed and then freeze-dried to obtain a modified chitosan clay stabilizer.

Further, in step S1, the mass ratio of chitosan, acid component and aldehyde component is 1:(0.16-0.6):(0.2-1.15).

Further, in step S1, the acid component is one of 2-acrylamide-2-methylpropanesulfonic acid, phosphorous acid, methacrylic acid, and acetic acid.

Further, in step S1, the aldehyde component is one of glutaraldehyde, salicylaldehyde, methylglyoxal, glyoxal and furfural.

Further, in step S1, the heating is at 45° C. for 4 hours to 12 hours.

Further, in step S1, NaOH with a concentration of 0.2-0.6 mol/L is used to adjust the pH value of the mixed solution to 4.5-6.5.

Further, in step S2, ethanol and distilled water are used for the washing.

Further, in step S2, the freeze-drying is carried out at 3-15 MPa and -40-60° C. for 10-24 hours.

The present invention also provides a chitosan oilfield clay stabilizer based on Mannich reaction, which is prepared according to the above preparation method. The temperature resistance of the clay stabilizer is up to 250° C., and the anti-swelling rate is greater than 90%.

Compared with the prior art, the present invention has at least the following beneficial effects:

The invention discloses a chitosan oilfield clay stabilizer and a preparation method thereof. Mannich reaction is adopted to prepare the clay stabilizer with chitosan, acid and aldehyde as raw materials, wherein chitosan is used as a natural organic macromolecule polymerization It has the advantages of wide source, low price, good biodegradability, etc., and it can be modified by active groups such as -OH and _-NH2 on its molecule, which lays the foundation for the synthesis of clay stabilizers with excellent performance. The foundation is established, and the problems of high toxicity and environmental pollution in the preparation of clay stabilizers existing in the prior art are solved.

The invention also discloses that the chitosan oil field clay stabilizer prepared by the above preparation method has the advantages of simple and convenient operation, low energy consumption, mild reaction conditions and high grafting efficiency through the Mannich reaction, and the synthesized clay stabilizer containing cations has the following advantages: Performance of heat and salt resistance. The introduced acid radical anions, such as carboxyl group and sulfonic acid group, as strong hydration groups, form multi-point adsorption with the surface of multiple clay particles, and then form a dense hydration film, which prevents and delays the contact between water molecules and the clay surface. To prevent clay hydration swelling; at the same time, the nitrogen cation contained in the side chain has a large degree of freedom of movement, which has a strong control effect on the dispersion and migration of clay particles, and has strong water washing resistance, and also has anti- High temperature, anti-salt, anti-pollution effect, is a clay stabilizer with excellent performance, and then enhances the application in stabilizing clay. Chitosan is generally dissolved in inorganic acid or organic acid, and cannot be directly dissolved in water. The acid component in the Mannich reaction can be used as a raw material for the reaction, and can also assist in dissolving chitosan to promote the occurrence of the reaction and improve the reaction efficiency.

The invention also discloses the application of the chitosan oilfield clay stabilizer. The material can be strongly adsorbed to the clay surface, is not easy to decompose, has a long validity period, and has a temperature resistance of 250°C and an anti-swelling rate of more than 90%.

Description of drawings

Figure 1 is a schematic diagram of the Mannich reaction of the present invention.

detailed description

In order to enable those skilled in the art to better understand the solutions of the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only It is an embodiment of a part of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

It should be noted that the terms "first" and "second" in the description and claims of the present invention and the above drawings are used to distinguish similar objects, but not necessarily used to describe a specific sequence or sequence. It is to be understood that the data so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein can be practiced in sequences other than those illustrated or described herein. Furthermore, the terms "comprising" and "having", as well as any variations thereof, are intended to cover a non-exclusive inclusion, for example, a process, method, system, product or device comprising a sequence of steps or elements is not necessarily limited to the expressly listed instead, may include other steps or elements not explicitly listed or inherent to the process, method, product or apparatus.

As shown in Figure 1, a chitosan oilfield clay stabilizer based on Mannich reaction, the steps are as follows:

(1) under stirring condition, chitosan and acid component as amine component are joined in the water of 100mL, obtain uniform mixed solution;

(2) Add the aldehyde component to the above mixed solution, stir at 45°C for 4h-12h, then adjust the pH value of the mixed solution to 4.5-6.5 with NaOH, and the solid product will be precipitated. The solid product at this time includes the polymer after the reaction and unreacted monomers;

(3) Filter and wash the solid product with ethanol and distilled water, wash off the unreacted monomer on the polymer, and freeze-dry it at 3 to 15 MPa and -40 to -60°C for 10 to 24 hours to obtain modified chitosan Sugar Clay Stabilizer.

Fig. 1 is the Mannich reaction schematic diagram of the present invention, and wherein R1 is an acid component, specifically comprises a kind of in 2-acrylamide-2-methylpropanesulfonic acid, phosphorous acid, methacrylic acid, acetic acid; R2 is an aldehyde component, Specifically, it includes one of glutaraldehyde, salicylaldehyde, aceglyoxal, glyoxal, and furfural.

Wherein, the mass ratio of chitosan, acid component and aldehyde component is 1:(0.16-0.6):(0.2-1.15).

Wherein, the concentration of NaOH is 0.2-0.6 mol/L.

Example 1:

(1) under stirring condition, the 2-acrylamide-2-methylpropanesulfonic acid of 2g chitosan and 1.09g is joined in the water of 100mL, obtains uniform mixed solution;

(2) Add 0.53g of glutaraldehyde into the above mixed solution and stir at 45°C for 4h. At this time, the mass ratio of chitosan, 2-acrylamide-2-methylpropanesulfonic acid and glutaraldehyde is 1:0.5 : 0.25, then slowly add the NaOH of 0.2mol/L, the pH of mixed solution is adjusted to 4.5, finally separate out and obtain solid product;

(3) The solid product was filtered and washed with ethanol and distilled water, and then freeze-dried at a temperature of -40° C. and a pressure of 3 MPa to obtain a modified chitosan clay stabilizer after 10 hours.

Example 2:

(1) under stirring condition, the phosphorous acid of 2g chitosan and 0.41g is added into the water of 100mL, obtains uniform mixed solution;

(2) Add 1.22g of salicylaldehyde solution into the above mixed solution, and stir at 45°C for 6 hours. At this time, the mass ratio of chitosan, phosphorous acid and salicylaldehyde is 1:0.2:0.6, and then slowly add 0.3mol/ 1 of NaOH, the pH of the mixed solution is adjusted to 5, and the solid product is finally separated out;

(3) The solid product was filtered and washed with ethanol and distilled water, and then freeze-dried at a temperature of -45° C. and a pressure of 6 MPa to obtain a modified chitosan clay stabilizer after 15 hours.

Example 3:

(1) under stirring condition, the methacrylic acid of 2g chitosan and 0.86g is joined in the water of 100mL, obtains uniform mixed solution;

(2) Add 1.15g of methylglyoxal solution into the above mixed solution, and stir at 45°C for 7 hours. At this time, the mass ratio of chitosan, methacrylic acid, and methylglyoxal is 1:0.4:0.3, and then slowly add 0.4mol/L NaOH, the pH of the mixed solution is adjusted to 5.5, and finally precipitated to obtain a solid product;

(3) The solid product was filtered and washed with ethanol and distilled water, and then freeze-dried at a temperature of -50° C. and a pressure of 10 MPa to obtain a modified chitosan clay stabilizer after 18 hours.

Example 4:

(1) under stirring condition, the acetic acid of 2g chitosan and 0.6g is joined in the water of 100mL, obtains uniform mixed solution;

(2) Add 1.16g glyoxal solution into the above mixed solution, stir at 45°C for 8h, at this time the mass ratio of chitosan, acetic acid, glyoxal is 1:0.3:0.5, then slowly add 0.6mol/L NaOH, the pH of the mixed solution is adjusted to 6.5, and finally precipitated to obtain a solid product;

(3) The solid product was filtered and washed with ethanol and distilled water, and then freeze-dried at a temperature of -60° C. and a pressure of 15 MPa to obtain a modified chitosan clay stabilizer after 24 hours.

Example 5:

(1) under stirring condition, the acetic acid of 2g chitosan and 0.32g is joined in the water of 100mL, obtains uniform mixed solution;

(2) 0.4g furfural solution is added in the above-mentioned mixed solution, after stirring at 45 ℃ for 9h, the mass ratio of chitosan, acetic acid, furfural is 1:0.16:0.2 at this moment, then slowly add the NaOH of 0.5mol/L, will The pH of the mixed solution was adjusted to 6, and a solid product was finally precipitated;

(3) The solid product was filtered and washed with ethanol and distilled water, and then freeze-dried at a temperature of -50° C. and a pressure of 13 MPa to obtain a modified chitosan clay stabilizer after 22 hours.

Embodiment 6:

(1) under stirring condition, the acetic acid of 2g chitosan and 0.32g is joined in the water of 100mL, obtains uniform mixed solution;

(2) Add 2.3g glyoxal solution into the above mixed solution, and stir at 45°C for 10h. At this time, the mass ratio of chitosan, acetic acid, and glyoxal is 1:0.16:1.15, and then slowly add 0.2mol/L NaOH, the pH of the mixed solution is adjusted to 6, and finally precipitated to obtain a solid product;

(3) The solid product was filtered and washed with ethanol and distilled water, and then freeze-dried at a temperature of -50° C. and a pressure of 3 MPa to obtain a modified chitosan clay stabilizer after 15 hours.

Embodiment 7:

(1) under stirring condition, the methacrylic acid of 2g chitosan and 1.2g is joined in the water of 100mL, obtains uniform mixed solution;

(2) Add 0.77g of methylglyoxal solution into the above mixed solution, and stir at 45°C for 11h. At this time, the mass ratio of chitosan, methacrylic acid, and methylglyoxal is 1:0.6:0.2, and then slowly add 0.4mol/L NaOH, the pH of the mixed solution is adjusted to 5, and finally precipitated to obtain a solid product;

(3) The solid product was filtered and washed with ethanol and distilled water, and then freeze-dried at a temperature of -40° C. and a pressure of 15 MPa to obtain a modified chitosan clay stabilizer after 22 hours.

Embodiment 8:

(1) under stirring condition, the phosphorous acid of 2g chitosan and 1.2g is added in the water of 100mL, obtains uniform mixed solution; Then slowly add the NaOH of 0.6mol/L, the pH of mixed solution is adjusted to 4.5, Final separation obtains solid product;

(2) 2.3g salicylaldehyde solution is added in the above-mentioned mixed solution, after stirring for 12h at 45 DEG C, the mass ratio of chitosan, phosphorous acid and salicylaldehyde is 1:0.6:1.15 at this moment,

(3) The solid product was filtered and washed with ethanol and distilled water, and then freeze-dried at a temperature of -60° C. and a pressure of 13 MPa to obtain a modified chitosan clay stabilizer after 22 hours.

According to "SY/T5971-94 Performance Evaluation Method of Clay Stabilizer for Water Injection", the anti-swelling rate and validity period of the product were evaluated at a temperature of 250°C and a salinity of 200,000 mg/L. The results are shown in Table 1.

Table 1. Performance comparison of clay stabilizers

The present invention mixes chitosan, acid component and aldehyde component in different proportions and prepares the performance data of clay stabilizer as shown in table 1, as can be seen that the chitosan oil field prepared based on Mannich reaction in embodiment 1-8 The anti-swelling rate of the clay stabilizer is all greater than 90%, and the temperature resistance is all higher than 250°C, indicating that the clay stabilizer developed by the present invention has a good ability to prevent bentonite hydration under the condition of 250°C and salinity of 200000mg/L. ability to swell.

Claims (4)

1. A preparation method of a chitosan oil field clay stabilizer based on Mannich reaction is characterized by comprising the following specific steps:

s1, mixing chitosan, an acid component and an aldehyde component, heating to obtain a mixed solution, and adjusting the pH value of the mixed solution to 4.5-6.5 to obtain a solid product;

s2, washing the solid product, and then carrying out freeze drying to obtain a modified chitosan clay stabilizer;

in the step S1, the mass ratio of the chitosan to the acid component to the aldehyde component is 1 (0.16-0.6) to 0.2-1.15;

in the step S1, the acid component is one of 2-acrylamide-2-methylpropanesulfonic acid, phosphorous acid, methacrylic acid and acetic acid;

in the step S1, the aldehyde component is one of glutaraldehyde, salicylaldehyde, methylglyoxal, glyoxal and furfural;

in the step S1, heating for 4h to 12h at 45 ℃;

in the step S2, the freeze drying is carried out for 10 to 24 hours under the conditions of 3 to 15MPa and-40 to-60 ℃.

2. The preparation method of the chitosan oilfield clay stabilizer based on the Mannich reaction as claimed in claim 1, wherein in the step S1, naOH with a concentration of 0.2 to 0.6mol/L is used to adjust the pH value of the mixed solution.

3. The preparation method of the chitosan oil field clay stabilizer based on Mannich reaction according to claim 1, wherein in step S2, ethanol and distilled water are used for washing.

4. A chitosan oil field clay stabilizer based on Mannich reaction, which is prepared according to the preparation method of any one of claims 1 to 3, and has temperature resistance of 250 ℃ and swelling resistance rate of more than 90%.

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