Barium sulfate scale inhibitor, its preparation method and application

Abstract

The application discloses a barium sulfate scale inhibitor and a preparation method and application thereof, and belongs to the technical field of high polymer materials. The barium sulfate scale inhibitor is obtained by graft copolymerization of taurine monomers and L-cysteine monomers on poly succinimide. In the application, taurine and L-cysteine are used as monomers, and are grafted and copolymerized on poly succinimide under the catalysis of sodium hypophosphite, so as to obtain a water-soluble graft copolymer barium sulfate scale inhibitor containing carboxyl, amido and sulfonic acid groups. The inhibition rate of the barium sulfate scale inhibitor to barium sulfate is above 90%, and the barium sulfate scale inhibitor has good barium scale inhibition performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high polymer materials, and particularly relates to a barium sulfate scale inhibitor and a preparation method and application thereof. BACKGROUND

[0002] With the continuous exploitation of oil, most oilfields are currently in the middle and late development stage. Moreover, the formation energy cannot meet the normal production of the oilfield, and thus artificial water injection is needed to supplement the energy. Oilfield production wastewater can cause serious pollution to the environment. Therefore, in actual production, produced water is mostly re-injected into the formation after simple process treatment. The oilfield formation water contains a large amount of scale-forming ions, and the oilfield water injection components are more complex, and thus there is fluid incompatibility between the injected water and the formation water, and reactions between incompatible ions easily cause scaling. In addition, factors such as the temperature, pH value and formation pressure of the oil layer also change with oil production, resulting in the decrease of the solubility of scale-forming anions and cations in the formation water and the precipitation of the scale-forming anions and cations.

[0003] The oilfield scaling problem poses a huge challenge from both economic and technical aspects. In order to alleviate this problem, adding a chemical scale inhibitor is currently the most mainstream method for delaying or preventing scale. However, the current commercial scale inhibitor has the problems of poor scale inhibition performance, and the need for compounding use in application, resulting in high cost and the like. SUMMARY

[0004] The purpose of the present application is to provide a barium sulfate scale inhibitor and a preparation method and application thereof. The purpose is to solve the problems of the current commercial scale inhibitor, such as poor scale inhibition performance, and the need for compounding use in application, resulting in high cost and the like.

[0005] In a first aspect, the present application provides a barium sulfate scale inhibitor, which is obtained by graft copolymerization of taurine monomers and L-cysteine monomers on poly succinimide, and has the following structure (I):

[0006]

[0007] In formula (I), X, Y, Z are independently any integer from 1 to 10; for example, X can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10; for example, Y can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10; for example, Z can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.

[0008] The barium sulfate scale inhibitor provided by the present application is obtained by graft copolymerization of taurine monomers and L-cysteine monomers on poly succinimide. Since the side chain hydrophilic groups are introduced on the poly succinimide, the barium sulfate scale inhibition performance of the barium sulfate scale inhibitor can be significantly improved.

[0009] In a second aspect, the present application provides a method for preparing the above-mentioned barium sulfate scale inhibitor, comprising the following steps:

[0010] S1, providing a poly succinimide aqueous solution, a taurine alkali solution, an L-cysteine alkali solution, and an initiator aqueous solution;

[0011] S2, adding the taurine alkali solution, the L-cysteine alkali solution, and the initiator aqueous solution dropwise into the poly succinimide aqueous solution, adjusting the pH value of the solution to be alkaline, performing a copolymerization reaction, and obtaining the barium sulfate scale inhibitor.

[0012] In some embodiments, in step S1, the molar ratio of the poly succinimide, the taurine, and the L-cysteine is 1:(0.5-1.5):(0.5-1.5), for example, it can be 1:0.5:0.5, 1:1:0.5, 1:1.5:0.5, 1:0.5:1, 1:1:1, 1:1.5:1, 1:0.5:1.5, 1:1:1.5, 1:1.5:1.5, or other numerical ratios within the range.

[0013] In some preferred embodiments, the molar ratio of the poly succinimide, the taurine, and the L-cysteine is 1:1:1.

[0014] In some embodiments, in step S1, in the poly succinimide aqueous solution, the mass-volume ratio of the poly succinimide to water is 1:3; in the taurine alkali solution, the mass-volume ratio of the taurine to the alkali solution is 1:2; in the L-cysteine alkali solution, the mass-volume ratio of the L-cysteine to the alkali solution is 1:2; and in the initiator aqueous solution, the mass-volume ratio of the initiator to water is 1:2, and the amount of the initiator added is 3-5% of the total mass of the poly succinimide, the taurine, and the L-cysteine, for example, it can be 3%, 3.5%, 4%, 4.5%, 5%, or other numerical values within the range.

[0015] In some preferred embodiments, the amount of the initiator added is 4% of the total mass of the poly succinimide, the taurine, and the L-cysteine.

[0016] In some embodiments, the alkali solution in the taurine alkali solution and the alkali solution in the L-cysteine alkali solution are both sodium hydroxide solutions, and the mass concentration of the sodium hydroxide solution is 15%.

[0017] In some embodiments, in step S2, the dropwise adding time is 0.5-1 h, for example, it can be 0.5 h, 0.6 h, 0.7 h, 0.8 h, 0.9 h, 1 h, or other numerical values within the range; and the pH value is 8-11, for example, it can be 8, 8.5, 9, 9.5, 10, 10.5, 11, or other numerical values within the range.

[0018] In some embodiments, in step S2, the temperature of the copolymerization reaction is 40–60°C, for example, 40°C, 45°C, 50°C, 55°C, 60°C or other values ​​within this range; the time is 4–6 hours, for example, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours or other values ​​within this range.

[0019] In some embodiments, the method further includes a step of purifying the barium sulfate scale inhibitor obtained in step S2.

[0020] In some preferred embodiments, purification includes passing the barium sulfate antiscalant obtained in step S2 through a 2000 Da dialysis membrane and freeze-drying for 48 h to obtain purified barium sulfate antiscalant.

[0021] In a third aspect, the present invention provides the application of the above-mentioned barium sulfate scale inhibitor in oilfield water treatment systems.

[0022] The beneficial effects of this invention are as follows: Unlike the prior art, this invention uses taurine and L-cysteine ​​as monomers, and under the catalysis of sodium hypophosphite, they are grafted and copolymerized onto polysuccinimide to obtain a water-soluble graft copolymer barium sulfate scale inhibitor containing carboxyl, amide and sulfonic acid groups. This barium sulfate scale inhibitor has an inhibition rate of over 90% for barium sulfate and has excellent barium scale inhibition performance. Attached Figure Description

[0023] Figure 1 This is the infrared spectrum of the barium sulfate scale inhibitor prepared in Example 2 of this invention. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] Experimental methods not specified in the examples are generally performed under conventional conditions and as described in the manual, or as recommended by the manufacturer. Unless otherwise specified, the general equipment, materials, reagents, etc. used are commercially available.

[0026] Example 1

[0027] A method for preparing a barium sulfate scale inhibitor includes the following steps:

[0028] S1, adding poly succinimide (PSI) and deionized water into a three-necked flask, wherein the mass-volume ratio of poly succinimide to deionized water is 1:3, and the temperature is raised to 50℃, and uniform stirring is performed to form a suspension; weighing sodium hypophosphite (SHP) and adding deionized water, wherein the mass-volume ratio of sodium hypophosphite to deionized water is 1:2, to obtain a sodium hypophosphite aqueous solution; then weighing taurine (Tau) and L-cysteine (L-Cys) and adding them into a 15% sodium hydroxide solution, wherein the mass-volume ratio of taurine and L-cysteine to the 15% sodium hydroxide solution is 1:2, respectively, to obtain a taurine alkali solution and an L-cysteine alkali solution;

[0029] S2, adding the taurine alkali solution and the L-cysteine alkali solution dropwise into the three-necked flask, and then adding the sodium hypophosphite solution dropwise into the three-necked flask, and the dropwise adding time is controlled to be 0.5-1h; wherein the molar ratio of poly succinimide to taurine and L-cysteine is 1:0.5:0.5, and the added amount of sodium hypophosphite is 4% of the total mass of poly succinimide, taurine and L-cysteine; after the dropwise adding is completed, the pH value of the solution in the three-necked flask is adjusted with a 15% sodium hydroxide solution, and is controlled to be 8-11; after the pH value of the system solution is stable, a timed reaction is performed for 5h, and the reaction temperature is controlled to be 50℃; after the reaction is completed, cooling is performed, to obtain a copolymer solution; the copolymer solution is dialyzed in a 2000Da molecular weight dialysis bag to remove unreacted small molecule monomers; and after 48h of freeze drying, a purified water-soluble copolymer barium sulfate scale inhibitor is obtained.

[0030] Example 2

[0031] A preparation method of a barium sulfate scale inhibitor, comprising the following steps:

[0032] S1, adding poly succinimide (PSI) and deionized water into a three-necked flask, wherein the mass-volume ratio of poly succinimide to deionized water is 1:3, and the temperature is raised to 50℃, and uniform stirring is performed to form a suspension; weighing sodium hypophosphite (SHP) and adding deionized water, wherein the mass-volume ratio of sodium hypophosphite to deionized water is 1:2, to obtain a sodium hypophosphite aqueous solution; then weighing taurine (Tau) and L-cysteine (L-Cys) and adding them into a 15% sodium hydroxide solution, wherein the mass-volume ratio of taurine and L-cysteine to the 15% sodium hydroxide solution is 1:2, respectively, to obtain a taurine alkali solution and an L-cysteine alkali solution;

[0033] S2. Taurine alkaline solution and L-cysteine ​​alkaline solution are added dropwise to a three-necked flask, followed by sodium hypophosphite solution. The addition time is controlled at 0.5–1 h. The molar ratio of polysuccinimide to taurine and L-cysteine ​​is 1:1:1, and the amount of sodium hypophosphite added is 4% of the total mass of polysuccinimide, taurine, and L-cysteine. After the addition is complete, the pH of the solution in the three-necked flask is adjusted with a 15% sodium hydroxide solution and controlled at 8–11. After the pH of the solution stabilizes, the reaction is carried out for 5 h at a controlled temperature of 50 °C. After the reaction is completed, the solution is cooled to obtain a copolymer solution. The copolymer solution is dialyzed through a 2000 Da molecular weight dialysis bag to remove unreacted small molecule monomers. After 48 h of freeze-drying, a purified water-soluble copolymer barium sulfate scale inhibitor is obtained.

[0034] Infrared spectroscopy was performed on the water-soluble copolymer barium sulfate scale inhibitor prepared in this embodiment, and the results are as follows: Figure 1 As shown.

[0035] from Figure 1 It can be seen that it is 3403.07cm. -1 239.27cm -1 1660cm -1 1597.16cm -1 1399.80cm -1 1192.41cm -1 1048.03cm -1 813.57cm -1 740.99cm -1 527.54cm -1 Characteristic absorption peak, of which 3403.07 cm⁻¹ -1 The broad peak at 1660 cm⁻¹ is caused by the stretching vibrations of the OH group in the carboxylic acid group and the NH group in the amide group; -1 The peak at 1597.16 cm⁻¹ is caused by the stretching vibration of C=O in carboxylic acids. -1 The peak at 1399.80 cm⁻¹ is the stretching vibration absorption peak of the C=O band in amide II, indicating that PSI has successfully opened the ring; -1 The peak at 1192.41 cm⁻¹ is the stretching vibration peak of the S=O group in the sulfonic acid group. 1 The peak at 1048.03 cm⁻¹ is induced by the stretching vibration of CN in the amide group. -1 This is due to the vibration of the SO bond in the sulfonic acid group; finally, 813.57 cm. -1 740.99cm -1 527.54cm -1The peaks at 3300-3500 cm-1 are due to the vibration of N-H, S-H, C-H, and the above results show that taurine and L-cysteine have been grafted onto the polysuccinimide.

[0036] Example 3

[0037] A preparation method of a barium sulfate scale inhibitor, comprising the following steps:

[0038] S1, adding polysuccinimide (PSI) and deionized water into a three-necked flask, wherein the mass-volume ratio of the polysuccinimide to the deionized water is 1:3, and the temperature is raised to 60°C to form a suspension under uniform stirring; weighing sodium hypophosphite (SHP) and adding deionized water, wherein the mass-volume ratio of the sodium hypophosphite to the deionized water is 1:2 to obtain a sodium hypophosphite aqueous solution; then weighing taurine (Tau) and L-cysteine (L-Cys) and adding them into a 15% sodium hydroxide solution, wherein the mass-volume ratio of the taurine and the L-cysteine to the 15% sodium hydroxide solution is 1:2 respectively to obtain a taurine alkali solution and an L-cysteine alkali solution respectively;

[0039] S2, adding the taurine alkali solution and the L-cysteine alkali solution dropwise into the three-necked flask, and then adding the sodium hypophosphite solution dropwise into the three-necked flask, and the dropwise adding time is controlled within 0.5-1h; wherein the molar ratio of the polysuccinimide to the taurine and the L-cysteine is 1:1.5:1.5, and the added amount of the sodium hypophosphite is 4% of the total mass of the polysuccinimide, the taurine and the L-cysteine; after the dropwise adding is completed, adjusting the pH value of the solution in the three-necked flask with a 15% sodium hydroxide solution and controlling it within 8-11; after the pH value of the system solution is stable, timing reaction for 6h, and the reaction temperature is controlled within 60°C; after the reaction is completed, cooling to obtain a copolymer solution; removing the unreacted small molecule monomers in the copolymer solution by dialysis in a 2000Da molecular weight dialysis bag, and obtaining a purified water-soluble copolymer barium sulfate scale inhibitor after 48h of freeze-drying.

[0040] Comparative Example

[0041] Taking an equal amount of polysuccinimide as in Example 2 without grafting treatment, and directly using it as a barium sulfate scale inhibitor.

[0042] Evaluation of scale inhibitor performance

[0043] The scale inhibition performance of the copolymer products prepared in Examples 1-3 and the comparative example on barium sulfate is tested, and the specific test method is as follows:

[0044] Accurately weigh 0.5g of the above scale inhibitor, dissolve it in a small amount of pure water, and transfer it to a 250mL volumetric flask and dilute to volume to obtain a scale inhibitor solution; take 200mL of pure water into a 250mL volumetric flask, add the pre-prepared BaCl2 solution, and make Ba... 2+ The content is 56 mg·mL -1 Add 3.75 mL of the above scale inhibitor solution to the barium chloride solution, let it stand for 10 minutes, and then add the pre-prepared Na2SO4 solution while shaking, so that SO42- 2- The content was 41.2 mg·mL. -1 Then dilute with pure water to the mark and pour into an Erlenmeyer flask. Place in a water bath at 50℃±1℃ for half an hour and let stand for 24 hours.

[0045] After the reaction was complete, the solution was cooled to room temperature and filtered through quantitative filter paper. The filtrate of BaSO4 was titrated with ethylenediaminetetraacetic acid (EDTA) standard solution to determine Ba. 2+ The concentration of [the substance / method] was determined. The test results are shown in Table 1.

[0046] Table 1. Scale inhibition performance test results of the scale inhibitors prepared in Examples 1-3 and the comparative examples.

[0047] Serial number Dose of scale inhibitor (mg / L) Barium sulfate scale inhibition rate Example 1 30 95％ Example 2 30 97％ Example 3 30 91％ Comparative example 30 52％

[0048] As can be seen from the results in Table 1, compared with the low scale inhibition performance of the scale inhibitor containing only polysuccinimide in the comparative example, the present invention uses polysuccinimide, taurine and L-cysteine ​​as raw materials to obtain a water-soluble copolymer barium sulfate scale inhibitor through graft copolymerization by the catalytic action of a catalyst. It has excellent scale inhibition effect on barium sulfate. When the scale inhibitor dosage is 30 mg / L, the inhibition rate of barium sulfate is 91% to 97%, which realizes the prevention of the formation of barium sulfate scale in water with high hardness, high sulfate ion and poor water quality at a low concentration.

[0049] It should be noted that all the above embodiments belong to the same inventive concept, and the descriptions of each embodiment have different focuses. Where the description in a particular embodiment is not detailed, please refer to the description in other embodiments.

[0050] The embodiments described above are merely illustrative of implementation methods of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A barium sulfate scale inhibitor characterized by, The scale inhibitor is obtained by graft copolymerization of taurine monomer and L-cysteine monomer on poly succinimide, and has the structure shown in formula (I). In formula (I), X, Y, Z are independently any integer from 1 to 10. The preparation method of the barium sulfate scale inhibitor comprises the following steps: S1, providing a poly succinimide aqueous solution, a taurine alkali solution, an L-cysteine alkali solution and an initiator aqueous solution; S2, adding the taurine alkali solution, the L-cysteine alkali solution and the initiator aqueous solution into the poly succinimide aqueous solution dropwise, adjusting the pH value of the solution to be alkaline, and performing copolymerization to obtain the barium sulfate scale inhibitor.

2. The method of preparing a barium sulfate scale inhibitor of claim 1, characterized in that, Comprising the following steps: S1, providing a poly succinimide aqueous solution, a taurine alkali solution, an L-cysteine alkali solution and an initiator aqueous solution; S2, adding the taurine alkali solution, the L-cysteine alkali solution and the initiator aqueous solution into the poly succinimide aqueous solution dropwise, adjusting the pH value of the solution to be alkaline, and performing copolymerization to obtain the barium sulfate scale inhibitor.

3. The method for preparing the barium sulfate scale inhibitor according to claim 2, characterized in that, In step S1, the molar ratio of the poly succinimide, the taurine and the L-cysteine is 1: (0.5-1.5): (0.5-1.5).

4. The method of preparing a barium sulfate scale inhibitor according to claim 3, wherein The molar ratio of the poly succinimide, the taurine and the L-cysteine is 1:1:

1.

5. The method for preparing the barium sulfate scale inhibitor according to claim 2, characterized in that, In the poly succinimide aqueous solution in step S1, the mass-volume ratio of the poly succinimide to the water is 1:3; In the taurine alkali solution, the mass-volume ratio of the taurine to the alkali solution is 1:2; In the L-cysteine alkali solution, the mass-volume ratio of the L-cysteine to the alkali solution is 1:2; In the initiator aqueous solution, the mass-volume ratio of the initiator to the water is 1:2, and the addition amount of the initiator is 3-5% of the total mass of the poly succinimide, the taurine and the L-cysteine.

6. The method of preparing a barium sulfate scale inhibitor of claim 5, wherein, The addition amount of the initiator is 4% of the total mass of the poly succinimide, the taurine and the L-cysteine.

7. The method for preparing the barium sulfate scale inhibitor according to claim 5, characterized in that, The alkali solution in the taurine alkali solution and the L-cysteine alkali solution is sodium hydroxide solution, and the mass concentration of the sodium hydroxide solution is 15%.

8. The method for preparing the barium sulfate scale inhibitor according to claim 2, characterized in that, In step S2, the dropwise adding time is 0.5-1 h, and the pH value is 8-11.

9. The method for preparing the barium sulfate scale inhibitor according to claim 2, characterized in that, In step S2, the temperature of the copolymerization is 40-60℃, and the time is 4-6 h.

10. The barium sulfate scale inhibitor of claim 1 is applied in an oilfield water treatment system.

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