An organic zirconium crosslinker, method of making, use and gels, proppants

Abstract

The application relates to the technical field of oil and gas field stimulation, and particularly discloses an organic zirconium crosslinking agent, a preparation method and application thereof, and a gel and a proppant, wherein the organic zirconium crosslinking agent is prepared by complex reaction of a zirconium salt or a zirconium oxide, a polyhydroxy ligand, an alcohol amine ligand and an organic acid. The polyhydroxy ligand, the alcohol amine ligand and the organic acid are combined and used, and can have a good crosslinking effect with the zirconium salt or the zirconium oxide. The prepared organic zirconium crosslinking agent is compounded with a modified polyacrylamide drag-reducing agent to form a gel with large viscosity, the viscosity of the drag-reducing agent is increased, and the requirement that a large amount of proppants is carried into a reservoir by using a high-viscosity fracturing fluid under a low discharge is met in the development of tight oil and gas.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field production enhancement technology, specifically to an organozirconium crosslinking agent and its preparation method, application, gel, and proppant. Background Technology

[0002] Unconventional oil and gas resources, especially shale gas and tight oil and gas, are widely distributed and have enormous development potential. However, due to the characteristics of unconventional oil and gas reservoirs, such as low porosity, low permeability, and strong heterogeneity, they are more difficult to extract than conventional oil and gas resources. In most cases, effective reservoir enhancement and stimulation measures are required.

[0003] Slickwater is a crucial fracturing fluid system for unconventional oil and gas extraction. Besides its cost advantage, slickwater can pump in large quantities of water and proppant at high flow rates, carrying the proppant into deeper fracture networks, thus creating larger fracture networks and venting areas. It has become standard practice in unconventional oil and gas reservoir fracturing operations. The main additives in slickwater typically account for 0.5% to 2.0% of the total volume, including drag reducers, surfactants, scale inhibitors, clay stabilizers, and bactericides. Among these, drag reducers are the core additive in slickwater fracturing fluids, and low-cost polyacrylamide-based drag reducers are a major component in shale gas slickwater fracturing fluid formulations. The main function of drag reducers is to alter the flow state of water in the pipeline, reducing frictional resistance and thus transmitting pressure from surface equipment to the wellbore as efficiently as possible.

[0004] In recent years, unconventional oil and gas resources, represented by tight oil and gas, have attracted much attention. Unlike shale gas development, these require the use of high-viscosity fluids to carry more proppant into the reservoir to achieve industrial production capacity. Patent CN112142909A discloses a method for synthesizing a drag-reducing agent. The modified polyacrylamide drag-reducing agent obtained according to the examples exhibits excellent drag-reducing performance, achieving a maximum drag reduction rate of 78% in field applications. However, its viscosity-enhancing properties are generally limited, and at lower flow rates, it cannot adequately meet the requirements of using high-viscosity fracturing fluids to carry large amounts of proppant into the reservoir during tight oil and gas development. Summary of the Invention

[0005] The purpose of this invention is to provide an organozirconium crosslinking agent, which, when combined with a modified polyacrylamide drag reducer, can form a gel with high viscosity, thereby increasing the viscosity of the drag reducer. This is to meet the requirement of using high-viscosity fracturing fluid to carry a large amount of proppant into the reservoir at lower displacement levels in tight oil and gas development.

[0006] In addition, the present invention also provides the above-mentioned organozirconium crosslinking agent and its preparation method, application, as well as gels and support agents prepared from the above-mentioned organozirconium crosslinking agent.

[0007] This invention is achieved through the following technical solution:

[0008] An organozirconium crosslinking agent is prepared by complexing zirconium salt or zirconium oxide with polyhydroxy ligands, alcoholamine ligands and organic acids.

[0009] The zirconium salt or zirconium oxide of the present invention may be the following substances: zirconium acetate, zirconium fluoride, zirconium chloride, zirconium butoxide, zirconium propoxide, zirconium acetylacetonate, zirconium isopropoxide, basic zirconium carbonate, zirconium ethanol, zirconium sulfate, zirconium oxychloride, zirconium tert-butoxide, zirconium oxide, and zirconium hydroxide.

[0010] The polyhydroxy ligands and alkanolamine ligands of the present invention can undergo complexation reactions with zirconium salts or zirconium oxides, and the organic acid is used to provide an acidic environment for the reaction system.

[0011] The applicant discovered this through implementation:

[0012] The combined use of polyhydroxy ligands, alkanolamine ligands, and organic acids achieves excellent crosslinking effects with zirconium salts or zirconium oxides; all three are indispensable, otherwise the crosslinking effect cannot be achieved. The organozirconium crosslinking agent prepared in this invention, when combined with a modified polyacrylamide drag reducer, can form a gel with high viscosity, increasing the viscosity of the drag reducer to meet the requirements of using high-viscosity fracturing fluids to carry large amounts of proppant into the reservoir at lower displacement rates in tight oil and gas development.

[0013] Furthermore, the mass ratio of zirconium salt or zirconium oxide to polyhydroxy ligand, alcohol amine ligand, and organic acid is 2~10:5~30:10~30:10~30.

[0014] Furthermore, polyhydroxy ligands are polyhydroxy compounds, that is, compounds containing multiple hydroxyl groups.

[0015] Polyhydroxy compounds include the following substances: glucose, gluconic acid, sodium gluconate, sorbitol, mannitol, lactose, lactitol, lactobionic acid, sodium lactobionic acid, galactose, galobionic acid, sodium galobionic acid, and glycerol.

[0016] The complexation process between polyhydroxy ligands and zirconium ions is very complex. The variety of ligands can lead to an increase in side reactions, affecting the stability and crosslinking performance of the final crosslinking agent. Therefore, during the complexation reaction, one or two of the above-mentioned polyhydroxy compounds should be used, preferably one.

[0017] Furthermore, the organic acid is a carboxylic acid type organic acid.

[0018] Carboxylic acid type organic acids include at least one of the following: formic acid, acetic acid, lactic acid, sorbic acid, oxalic acid, citric acid, tartaric acid, benzoic acid, succinic acid, malic acid, quinic acid, ascorbic acid, and salicylic acid.

[0019] The main purpose of adding organic acids is to adjust the pH. Adding one or more acids will not have a significant impact on the effect. However, for ease of operation, it is preferable to use only one.

[0020] Furthermore, the amine ligands include the following substances: diethanolamine, triethanolamine, N-methyldiethanolamine, isopropanolamine, ethanolamine phosphate, diethylene glycolamine, triisopropanolamine, diisopropanolamine, n-butylethanolamine, N-acetylethanolamine, tert-butyldiethanolamine, and N-butyldiethanolamine.

[0021] The complexation process between alkanolamine ligands and zirconium ions is very complex. The variety of ligands can lead to an increase in side reactions, affecting the stability and crosslinking performance of the final crosslinking agent. Therefore, during the complexation reaction, one or two of the alkanolamine ligands mentioned above should be used, with one being preferred.

[0022] Furthermore, during the complexation reaction, the polyhydroxy ligand and the alcoholamine ligand are added in two steps. First, a complexing agent with a smaller K value is added, where K is the equilibrium constant of the complexation reaction.

[0023] The preparation process of organozirconium crosslinking agents requires the optimal selection of polyhydroxy ligands and alkanolamine ligands, and their addition in two steps. This is because complexation reactions are typically complex, involving both main and side reactions, including monoligand and multiligand complexation reactions. The stability of the complex is generally represented by the equilibrium constant K; a larger K value indicates a more stable complex. For example, in Example 1, sodium gluconate first complexes with zirconium ions in the reaction system, and then diethanolamine, with a larger K value, is added to further complex with the remaining zirconium ions in the solution, forming a stable multiligand complex.

[0024] Furthermore, the polyhydroxy ligand is sodium lactobionate, and the alcoholamine ligand is diethanolamine; during the crosslinking reaction, sodium lactobionate is added first, followed by diethanolamine.

[0025] Furthermore, the polyhydroxy ligand is sodium gluconate, and the alcoholamine ligand is triethanolamine; during the crosslinking reaction, sodium gluconate is added first, followed by triethanolamine.

[0026] The preparation method of the organozirconium crosslinking agent includes the following steps:

[0027] S1. After adding zirconium salt or zirconium oxide to water to form a transparent solution or suspension, heat it in a water bath.

[0028] S2. Add polyhydroxy ligands to the solution obtained in step S1 and stir for 1-2 hours. Then add alcoholamine ligands and continue stirring for 1-8 hours.

[0029] S3. After preparing an aqueous solution of the organic acid, slowly add it dropwise to the solution in step S2. After reacting for 1 to 5 hours, remove the solution to obtain the organozirconium crosslinking agent.

[0030] Furthermore, the temperature for the complexation reaction is 40~90℃.

[0031] The application of organozirconium crosslinking agents in tight oil and gas development involves combining the aforementioned organozirconium crosslinking agents with modified polyacrylamide drag reducers.

[0032] A gel formulated with an organozirconium crosslinking agent and modified polyacrylamide.

[0033] A support agent comprising the above-mentioned gel.

[0034] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0035] This invention utilizes a combination of polyhydroxy ligands, alkanolamine ligands, and organic acids to achieve excellent crosslinking effects with zirconium salts or zirconium oxides. The prepared organic zirconium crosslinking agent, when combined with a modified polyacrylamide drag reducer, can form a gel with high viscosity, increasing the viscosity of the drag reducer to meet the requirements of using high-viscosity fracturing fluid to carry large amounts of proppant into the reservoir at lower displacement levels in tight oil and gas development. Attached Figure Description

[0036] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0037] Figure 1 Image of a high-viscosity gel prepared by combining the crosslinking agent prepared in Example 1 with modified polyacrylamide;

[0038] Figure 2 Image showing the addition of ceramic particles to form a support for a high-viscosity gel prepared by combining the crosslinking agent prepared in Example 1 with modified polyacrylamide. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0040] Example 1

[0041] An organozirconium crosslinking agent is prepared by complexing zirconium salt or zirconium oxide with polyhydroxy ligands, alcoholamine ligands and organic acids.

[0042] In the embodiments, zirconium ions are provided by zirconium oxychloride; the polyhydroxy ligand is sodium lactobionate, the alcoholamine ligand is diethanolamine, and the organic acid is citric acid.

[0043] The preparation process of the organozirconium crosslinking agent in this embodiment is as follows:

[0044] S1. According to the mass fraction, take 2 parts of zirconium oxychloride and add them to a dry flask. Add 40 parts of water to dissolve the zirconium oxychloride and place it in a 70°C water bath with stirring.

[0045] S2. Add 10 parts of sodium lactobionate to the solution obtained in step S1. After it is completely dissolved, add 10 parts of diethanolamine and continue stirring for 4 hours.

[0046] S3. Add 20 parts of citric acid to 40 parts of water to prepare an aqueous solution. Then, slowly add the solution from step S2 dropwise. After the addition is complete, continue the reaction for 1 hour and then remove the solution to obtain organozirconium crosslinking agent 1.

[0047] According to Example 4 of patent CN112142909A, after synthesizing modified polyacrylamide and preparing a 0.3% aqueous solution, the viscosity was measured to be 30 mPa·s using a six-speed rotational viscometer. Then, by adding 1% (by volume) of organic zirconium crosslinking agent 1, a high-viscosity gel was obtained. Figure 1 As shown. Adding 20% ​​(by weight) of 40 / 70 mesh ceramsite to a high-viscosity gel and stirring until homogeneous, the proppant showed no significant sedimentation, as indicated. Figure 2 As shown.

[0048] Example 2

[0049] This embodiment is based on Embodiment 1, and the difference between it and Embodiment 1 is as follows:

[0050] In this embodiment, zirconium hydroxide was used to provide zirconium ions, sodium gluconate was used as the polyhydroxy ligand, triethanolamine was used as the alkanolamine ligand, and lactic acid was used as the organic acid. Furthermore, the mass ratio of zirconium hydroxide to the polyhydroxy ligand, alkanolamine ligand, and organic acid differed from that in Example 1.

[0051] The preparation process of the organozirconium crosslinking agent in this embodiment is as follows:

[0052] S1. According to the mass fraction, take 4 parts of zirconium hydroxide and add them to a dry flask. Add 20 parts of water to dissolve the zirconium hydroxide and place it in a 70°C water bath with stirring.

[0053] S2. Add 15 parts of sodium gluconate to the solution obtained in step S1. After it is completely dissolved, add 15 parts of triethanolamine and continue stirring for 4 hours.

[0054] S3. Add 30 parts of lactic acid to 40 parts of water to prepare an aqueous solution. Then, slowly add the solution from step S2 dropwise. After the addition is complete, continue the reaction for 1 hour and then remove the solution to obtain organozirconium crosslinking agent 2.

[0055] According to Example 4 of patent CN112142909A, after synthesizing modified polyacrylamide, a 0.3% aqueous solution was prepared, and the viscosity was measured to be 30 mPa·s using a six-speed rotational viscometer. Then, 1% by volume of organic zirconium crosslinking agent 2 was added to obtain a high-viscosity gel. 20% by mass of 40 / 70 mesh ceramsite was added to the high-viscosity gel and stirred until homogeneous.

[0056] Comparative Example 1:

[0057] This comparative example is based on Example 1, but differs from Example 1 in that organic acids are not used.

[0058] The preparation process of the organozirconium crosslinking agent in this comparative example is as follows:

[0059] S1. According to the mass fraction, take 2 parts of zirconium oxychloride and add them to a dry flask. Add 40 parts of water to dissolve the zirconium oxychloride and place it in a 70°C water bath with stirring.

[0060] S2. Add 10 parts of sodium lactobionate to the solution obtained in step S1. After it is completely dissolved, add 10 parts of diethanolamine and continue stirring for 1 hour to obtain organozirconium crosslinking agent 3.

[0061] According to Example 4 of patent CN112142909A, after synthesizing modified polyacrylamide, a 0.3% aqueous solution was prepared, and the viscosity was measured to be 30 mPa·s using a six-speed rotational viscometer. Then, 1% of the organic zirconium crosslinking agent 3 was added to the solution by volume, and the solution state did not change significantly. That is, the organic zirconium crosslinking agent prepared in this comparative example cannot increase the viscosity of the modified polyacrylamide.

[0062] Comparative Example 2:

[0063] This comparative example is based on Example 1, but differs from Example 1 in that diethanolamine is not used.

[0064] The preparation process of the organozirconium crosslinking agent in this comparative example is as follows:

[0065] S1. According to the mass fraction, take 2 parts of zirconium oxychloride and add them to a dry flask. Add 40 parts of water to dissolve the zirconium oxychloride and place it in a 70°C water bath with stirring.

[0066] S2. Add 10 parts of sodium lactobionate to the solution obtained in step S1. After it is completely dissolved, add 10 parts of citric acid and stir continuously for 1 hour to obtain organozirconium crosslinking agent 4.

[0067] According to Example 4 of patent CN112142909A, after synthesizing modified polyacrylamide, a 0.3% aqueous solution was prepared, and the viscosity was measured to be 30 mPa·s using a six-speed rotational viscometer. Then, 1% of the solution volume of organic zirconium crosslinking agent 4 was added, and white flocculent matter appeared in the solution without forming a gel. That is, the organic zirconium crosslinking agent prepared in this comparative example cannot increase the viscosity of the modified polyacrylamide.

[0068] Comparative Example 3:

[0069] This comparative example is based on Example 1, but differs from Example 1 in that sodium lactobionate is not used.

[0070] The preparation process of the organozirconium crosslinking agent in this comparative example is as follows:

[0071] S1. According to the mass fraction, take 2 parts of zirconium oxychloride and add them to a dry flask. Add 40 parts of water to dissolve the zirconium oxychloride and place it in a 70°C water bath with stirring.

[0072] S2. Add 10 parts of diethanolamine to the solution obtained in step S1. After it is completely dissolved, add 10 parts of citric acid and stir continuously for 1 hour to obtain organozirconium crosslinking agent 5.

[0073] According to Example 4 of patent CN112142909A, after synthesizing modified polyacrylamide, a 0.3% aqueous solution was prepared, and the viscosity was measured to be 30 mPa·s using a six-speed rotational viscometer. Then, 1% of the solution volume of organic zirconium crosslinking agent 5 was added, and white flocculent matter appeared in the solution without forming a gel. That is, the organic zirconium crosslinking agent prepared in this comparative example cannot increase the viscosity of the modified polyacrylamide.

[0074] Comparative Example 4:

[0075] This comparative example is based on Example 1, but differs from Example 1 in that the polyhydroxy ligand is not just sodium lactobionate, but a 1:1 mixture of sodium lactobionate and sodium gluconate.

[0076] The preparation process of the organozirconium crosslinking agent in this comparative example is as follows:

[0077] S1. According to the mass fraction, take 2 parts of zirconium oxychloride and add them to a dry flask. Add 40 parts of water to dissolve the zirconium oxychloride and place it in a 70°C water bath with stirring.

[0078] S2. Add 5 parts of sodium lactobionate and 5 parts of sodium gluconate to the solution obtained in step S1. After they are completely dissolved, add 10 parts of diethanolamine and continue stirring for 4 hours.

[0079] S3. Add 30 parts of lactic acid to 40 parts of water to prepare an aqueous solution, and then slowly add it dropwise to the solution in step S2. After the addition is complete, continue the reaction for 1 hour and then remove the solution to obtain organozirconium crosslinking agent 6.

[0080] According to Example 4 of patent CN112142909A, after synthesizing modified polyacrylamide, a 0.3% aqueous solution was prepared, and the viscosity was measured to be 30 mPa·s using a six-speed rotational viscometer. Then, 1% of the solution volume of organic zirconium crosslinking agent 6 was added, and white flocculent matter appeared in the solution without forming a gel. That is, the organic zirconium crosslinking agent prepared in this comparative example cannot increase the viscosity of the modified polyacrylamide.

[0081] The results of this comparative example are compared with those of Example 1, and it can be seen that:

[0082] Crosslinking with two polyhydroxy ligands, sodium lactobionate and sodium gluconate, cannot achieve the same crosslinking effect as using only sodium lactobionate.

[0083] Comparative Example 5:

[0084] This comparative example is based on Example 1, but differs from Example 1 in that the amine ligand used is not only diethanolamine, but a 1:1 mixture of diethanolamine and triethanolamine.

[0085] The preparation process of the organozirconium crosslinking agent in this comparative example is as follows:

[0086] S1. According to the mass fraction, take 2 parts of zirconium oxychloride and add them to a dry flask. Add 40 parts of water to dissolve the zirconium oxychloride and place it in a 70°C water bath with stirring.

[0087] S2. Add 10 parts of sodium lactobionate to the solution obtained in step S1. After it is completely dissolved, add 5 parts of triethanolamine and 5 parts of diethanolamine.

[0088] S3. Add 30 parts of lactic acid to 40 parts of water to prepare an aqueous solution, and then slowly add it dropwise to the solution in step S2. After the addition is complete, continue the reaction for 1 hour and then remove the solution to obtain organozirconium crosslinking agent 7.

[0089] According to Example 4 of patent CN112142909A, after synthesizing modified polyacrylamide, a 0.3% aqueous solution was prepared, and the viscosity was measured to be 30 mPa·s using a six-speed rotational viscometer. Then, 1% of the solution volume of organic zirconium crosslinking agent 7 was added, and white flocculent matter appeared in the solution without forming a gel. That is, the organic zirconium crosslinking agent prepared in this comparative example cannot increase the viscosity of the modified polyacrylamide.

[0090] The results of this comparative example are compared with those of Example 1, and it can be seen that:

[0091] Crosslinking with diethanolamine and triethanolamine, two types of alcohol amine ligands, cannot achieve the same crosslinking effect as using diethanolamine and polyhydroxy ligands.

[0092] Comparative Example 6:

[0093] This comparative example is based on Example 1, except that the amine ligand used is triethanolamine instead of diethanolamine.

[0094] The preparation process of the organozirconium crosslinking agent in this comparative example is as follows:

[0095] S1. According to the mass fraction, take 2 parts of zirconium oxychloride and add them to a dry flask. Add 40 parts of water to dissolve the zirconium oxychloride and place it in a 70°C water bath with stirring.

[0096] S2. Add 10 parts of sodium lactobionate to the solution obtained in step S1. After it is completely dissolved, add 10 parts of triethanolamine and continue stirring for 1 hour.

[0097] S3. Add 20 parts of citric acid to 40 parts of water to prepare an aqueous solution. Then, slowly add the solution from step S2 dropwise. After the addition is complete, continue the reaction for 1 hour and then remove the solution to obtain organozirconium crosslinking agent 8.

[0098] According to Example 4 of patent CN112142909A, after synthesizing modified polyacrylamide, a 0.3% aqueous solution was prepared, and the viscosity was measured to be 30 mPa·s using a six-speed rotational viscometer. Then, 1% of the solution volume of organic zirconium crosslinking agent 8 was added, and white flocculent matter appeared in the solution without forming a gel. That is, the organic zirconium crosslinking agent prepared in this comparative example cannot increase the viscosity of the modified polyacrylamide.

[0099] Comparative Example 7:

[0100] This comparative example is based on Example 1, but differs from Example 1 in that the ratio of sodium lactobionate, diethanolamine, and citric acid is changed.

[0101] The preparation process of the organozirconium crosslinking agent in this comparative example is as follows:

[0102] S1. According to the mass fraction, take 2 parts of zirconium oxychloride and add them to a dry flask. Add 40 parts of water to dissolve the zirconium oxychloride and place it in a 70°C water bath with stirring.

[0103] S2. Add 15 parts of sodium lactobionate to the solution obtained in step S1. After it is completely dissolved, add 10 parts of triethanolamine and continue stirring for 1 hour.

[0104] S3. Add 30 parts of citric acid to 40 parts of water to prepare an aqueous solution. Then, slowly add the solution from step S2 dropwise. After the addition is complete, continue the reaction for 1 hour and then remove the solution to obtain organozirconium crosslinking agent 8.

[0105] According to Example 4 of patent CN112142909A, after synthesizing modified polyacrylamide, a 0.3% aqueous solution was prepared, and the viscosity was measured to be 30 mPa·s using a six-speed rotational viscometer. Then, 1% of the organic zirconium crosslinking agent 9 was added to the solution by volume, and the solution state did not change significantly. That is, the organic zirconium crosslinking agent prepared in this comparative example cannot increase the viscosity of the modified polyacrylamide.

[0106] Comparative Example 8:

[0107] This comparative example is based on Example 1, but differs from Example 1 in that the ratio of sodium lactobionate, diethanolamine, and citric acid is changed.

[0108] The preparation process of the organozirconium crosslinking agent in this comparative example is as follows:

[0109] S1. According to the mass fraction, take 2 parts of zirconium oxychloride and add them to a dry flask. Add 40 parts of water to dissolve the zirconium oxychloride and place it in a 70°C water bath with stirring.

[0110] S2. Add 10 parts of sodium lactobionate to the solution obtained in step S1. After it is completely dissolved, add 15 parts of triethanolamine and continue stirring for 1 hour.

[0111] S3. Add 20 parts of citric acid to 40 parts of water to prepare an aqueous solution. Then, slowly add the solution from step S2 dropwise. After the addition is complete, continue the reaction for 1 hour and then remove the solution to obtain organozirconium crosslinking agent 8.

[0112] According to Example 4 of patent CN112142909A, after synthesizing modified polyacrylamide, a 0.3% aqueous solution was prepared, and the viscosity was measured to be 30 mPa·s using a six-speed rotational viscometer. Then, 1% of the solution volume of organic zirconium crosslinking agent 10 was added. The solution showed white flocculent matter and did not form a gel. That is, the organic zirconium crosslinking agent prepared in this comparative example cannot increase the viscosity of the modified polyacrylamide.

[0113] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing an organozirconium crosslinking agent, characterized in that, Includes the following steps: S1. After adding zirconium salt or zirconium oxide to water to form a transparent solution or suspension, heat it in a water bath. S2. Add a polyhydroxy ligand to the solution obtained in step S1 and stir for 1-2 hours. Then add an alcoholamine ligand and continue stirring for 1-8 hours. The polyhydroxy ligand is one or two of glucose, gluconic acid, sodium gluconate, sorbitol, mannitol, lactose, lactitol, lactobionic acid, sodium lactobionic acid, galactose, galobionic acid, sodium galobionic acid, and glycerol. S3. After preparing an aqueous solution of the organic acid, slowly add it dropwise to the solution in step S2. After reacting for 1 to 5 hours, remove the solution to obtain the organozirconium crosslinking agent. The organic acid is a carboxylic acid.

2. The method for preparing an organozirconium crosslinking agent according to claim 1, characterized in that, The mass ratio of the zirconium salt or zirconium oxide to the polyhydroxy ligand, alcohol amine ligand, and organic acid is 2~10:5~30:10~30:10~30.

3. The method for preparing an organozirconium crosslinking agent according to claim 1, characterized in that, The carboxylic acid type organic acid includes at least one of formic acid, acetic acid, lactic acid, sorbic acid, oxalic acid, citric acid, tartaric acid, benzoic acid, succinic acid, malic acid, quinic acid, ascorbic acid, and salicylic acid.

4. The method for preparing an organozirconium crosslinking agent according to claim 1, characterized in that, The alkanolamine ligand is one or two of the following: diethanolamine, triethanolamine, N-methyldiethanolamine, isopropanolamine, ethanolamine phosphate, diethylene glycolamine, triisopropanolamine, diisopropanolamine, n-butylethanolamine, N-acetylethanolamine, tert-butyldiethanolamine, and N-butyldiethanolamine.

5. The method for preparing an organozirconium crosslinking agent according to claim 1, characterized in that, During the complexation reaction, the polyhydroxy ligand and the alcoholamine ligand are added in two steps. First, a complexing agent with a smaller K value is added, where K is the equilibrium constant of the complexation reaction.

6. The method for preparing an organozirconium crosslinking agent according to claim 5, characterized in that, The polyhydroxy ligand is sodium lactobionate, and the alcoholamine ligand is diethanolamine; sodium lactobionate is added first, followed by diethanolamine, during the crosslinking reaction.

7. The method for preparing an organozirconium crosslinking agent according to claim 5, characterized in that, The polyhydroxy ligand is sodium gluconate, and the alcoholamine ligand is triethanolamine; sodium gluconate is added first, followed by triethanolamine, during the crosslinking reaction.

8. The preparation method according to claim 1, characterized in that, The temperature for the complexation reaction is 40~90℃.

9. The application of the organozirconium crosslinking agent prepared by the method according to any one of claims 1-7 in tight oil and gas development, characterized in that, In application, the organozirconium crosslinking agent prepared by any one of claims 1-7 is combined with the modified polyacrylamide drag reducer.

10. A gel, characterized in that, It is prepared by combining the organozirconium crosslinking agent obtained by any one of the preparation methods described in claims 1-7 with modified polyacrylamide.

11. A support agent comprising the gel of claim 10.

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