Organic zirconium cross-linking agent, preparation method, application, gel and proppant

Abstract

The invention relates to the technical field of oil and gas field yield increase, and particularly discloses an organic zirconium cross-linking agent, a preparation method and application thereof, gel and a proppant, and the organic zirconium cross-linking agent is prepared by complexation reaction of zirconium salt or zirconium oxide with a polyhydroxy ligand, an alcohol amine ligand and organic acid. According to the invention, the polyhydroxy ligand, the alcohol amine ligand and the organic acid are combined for use and can play a very good cross-linking effect with zirconium salt or zirconium oxide, and the prepared organic zirconium cross-linking agent is compounded with the modified polyacrylamide resistance reducing agent to form gel with relatively high viscosity, so that the viscosity of the resistance reducing agent is increased, and the resistance reducing effect is improved. Therefore, the requirement that a high-viscosity fracturing fluid carrying a large number of propping agents enters a reservoir in tight oil and gas development under the low displacement condition is met.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas field production increase, and in particular to an organic zirconium cross-linking agent and a preparation method, application, gel and proppant. Background Art

[0002] Unconventional oil and gas resources, especially shale gas and tight oil and gas, are widely distributed and have huge development potential. However, due to the low porosity, low permeability and strong heterogeneity of unconventional oil and gas reservoirs, they are more difficult to exploit than conventional oil and gas resources. In most cases, effective measures to increase production and reform the reservoirs are required.

[0003] Slippery water is an important fracturing fluid system for unconventional oil and gas production. In addition to its cost advantage, slippery water can pump a large amount of water and proppants at high displacement, and can carry proppants into deeper fracture networks, thereby forming a larger fracture network and gas leakage area. It has become a standard practice for fracturing operations in unconventional oil and gas reservoirs. The main additives of slippery water generally account for 0.5% to 2.0% of the total volume of slippery water, including drag reducers, surfactants, scale inhibitors, clay stabilizers, and fungicides. Among them, drag reducers are the core additives of slippery water fracturing fluids, and low-cost polyacrylamide drag reducers are the main ingredients in the formula of shale gas slippery water fracturing fluids. The main function of the drag reducer is to change the flow state of water in the pipeline, so that the friction resistance of water flowing in the pipeline is reduced, so as to transfer the pressure provided by the ground equipment to the bottom of the well as efficiently as possible.

[0004] In recent years, unconventional oil and gas resources represented by tight oil and gas have attracted people's attention. Unlike the development of shale gas, it is necessary to use high-viscosity fluid to carry more proppants into the reservoir to obtain industrial production capacity. The patent CN112142909A discloses a method for synthesizing a drag reducing agent. The modified polyacrylamide drag reducing agent obtained according to the embodiment has excellent drag reducing performance. The maximum drag reducing rate can reach 78% when used on site. However, the viscosity increasing performance of the drag reducing agent is general. At a lower displacement, it cannot meet the demand of using high-viscosity fracturing fluid to carry a large amount of proppants into the reservoir in the development of tight oil and gas. Summary of the invention

[0005] The object of the present invention is to provide an organic zirconium cross-linking agent, which can form a gel with relatively high viscosity by compounding the organic zirconium cross-linking agent with a modified polyacrylamide drag reducing agent, thereby increasing the viscosity of the drag reducing agent to meet the demand of using high-viscosity fracturing fluid to carry a large amount of proppant into the reservoir in tight oil and gas development at a lower displacement.

[0006] In addition, the present invention also provides the above-mentioned organic zirconium cross-linking agent, a preparation method, and application thereof, as well as a gel and a proppant prepared from the above-mentioned organic zirconium cross-linking agent.

[0007] The present invention is achieved through the following technical solutions:

[0008] An organic zirconium crosslinking agent is prepared by complexing zirconium salt or zirconium oxide with polyhydroxy ligand, alcohol amine ligand and organic acid.

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

[0010] The polyhydroxy ligand and the alcohol amine ligand of the present invention can both undergo complexation reaction with zirconium salt or zirconium oxide, and the organic acid is used to provide an acidic environment for the reaction system.

[0011] The applicant discovered by achieving:

[0012] The combination of polyhydroxy ligands, alcohol amine ligands and organic acids can achieve a good cross-linking effect with zirconium salts or zirconium oxides. The three are indispensable, otherwise the cross-linking effect cannot be achieved. The organic zirconium cross-linking agent prepared by the present invention and the modified polyacrylamide drag reducing agent can form a gel with high viscosity, increase the viscosity of the drag reducing agent, so as to meet the demand of using high-viscosity fracturing fluid to carry a large amount of proppant into the reservoir in tight oil and gas development at a lower displacement.

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

[0014] Furthermore, the polyhydroxy ligand is a polyhydroxy compound, ie, a compound containing multiple hydroxyl groups.

[0015] Polyols include the following: glucose, gluconic acid, sodium gluconate, sorbitol, lactol, lactose, lactitol, lactobionic acid, sodium lactobionic acid, galactose, galactobionic acid, sodium galactobionic acid, and glycerol.

[0016] The complexation process of polyhydroxy ligands and zirconium ions is very complicated. The large number of ligand types will lead to more side reactions, affecting the stability and crosslinking performance of the final crosslinker. Therefore, during the complexation reaction, one or two of the above-mentioned polyhydroxy compounds are used, preferably one.

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

[0018] 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.

[0019] The main purpose of adding organic acid is to adjust the pH. Adding one or more has no significant effect on the effect. For ease of operation, it is preferred to use one.

[0020] Further, the alcoholamine ligand includes the following substances: diethanolamine, triethanolamine, N-methyldiethanolamine, isopropanolamine, phosphoethanolamine, diglycolamine, triisopropanolamine, diisopropanolamine, n-butylethanolamine, N-acetylethanolamine, tert-butyldiethanolamine and N-butyldiethanolamine.

[0021] The complexation process of the alcohol amine ligand and the zirconium ion is very complicated. The large number of ligand types will lead to more side reactions, affecting the stability and crosslinking performance of the final crosslinker. Therefore, during the complexation reaction, one or two of the above alcohol amine ligands are used, preferably one.

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

[0023] The preparation process of the organic zirconium crosslinker requires the optimization of polyhydroxy ligands and alcohol amine ligands, and the addition is divided into two steps, because the complex reaction is usually complicated and there are main and side reactions, single ligand complex reactions and multi-ligand complex reactions. The stability of the complex is generally represented by the complex reaction equilibrium constant K. The larger the K value, the more stable the complex. For example, in Example 1, sodium gluconate is first complexed with the zirconium ions in the reaction system, and then diethanolamine with a larger K value is added to complex with the remaining zirconium ions in the solution again to form a stable multi-ligand complex.

[0024] Furthermore, the polyhydroxy ligand is sodium lactobionate, and the alcoholamine ligand is diethanolamine; during the cross-linking reaction, sodium lactobionate is added first, and then diethanolamine is added.

[0025] Furthermore, the polyhydroxy ligand is sodium gluconate, and the alcohol amine ligand is triethanolamine; during the cross-linking reaction, sodium gluconate is added first, and then triethanolamine is added.

[0026] The preparation method of the organic zirconium cross-linking agent comprises the following steps:

[0027] S1. Add zirconium salt or zirconium oxide into water to form a transparent solution or suspension, and then heat it in a water bath;

[0028] S2, adding a polyhydroxy ligand to the solution obtained in step S1, stirring for 1 to 2 hours, then adding an alcohol amine ligand, and continuing to stir for 1 to 8 hours;

[0029] S3, preparing an aqueous solution of an organic acid, slowly dripping the aqueous solution into the solution of step S2, and continuing the reaction for 1 to 5 hours, then taking it out to obtain an organic zirconium crosslinking agent.

[0030] Furthermore, the temperature of the complexation reaction is 40-90°C.

[0031] The use of an organic zirconium cross-linking agent in the development of tight oil and gas comprises compounding the organic zirconium cross-linking agent described in any one of claims 1 to 10 with a modified polyacrylamide drag reducing agent for use.

[0032] A gel is prepared by compounding an organic zirconium cross-linking agent with modified polyacrylamide.

[0033] A proppant comprising the above gel.

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

[0035] The present invention uses a combination of polyhydroxy ligands, alcohol amine ligands and organic acids to achieve a good cross-linking effect with zirconium salts or zirconium oxides. The prepared organic zirconium cross-linking agent is compounded with a modified polyacrylamide drag reducing agent to form a gel with relatively high viscosity, thereby increasing the viscosity of the drag reducing agent to meet the need of using high-viscosity fracturing fluid to carry a large amount of proppant into the reservoir in tight oil and gas development at a relatively low displacement. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0037] Figure 1 This is a picture of a high viscosity gel prepared by compounding the cross-linking agent prepared in Example 1 with modified polyacrylamide;

[0038] Figure 2 This is a picture of a high viscosity gel prepared by compounding the cross-linking agent prepared in Example 1 with modified polyacrylamide and adding ceramsite to form a proppant. DETAILED DESCRIPTION

[0039] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary implementation modes of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0040] Embodiment 1:

[0041] An organic zirconium crosslinking agent is prepared by complexing zirconium salt or zirconium oxide with polyhydroxy ligand, alcohol amine ligand and organic acid.

[0042] In the embodiment, zirconium oxychloride is used to provide zirconium ions; the polyhydroxy ligand is sodium lactobionate, the alcohol amine ligand is diethanolamine, and the organic acid is citric acid.

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

[0044] S1. Take 2 parts of zirconium oxychloride by mass and add them to a dry flask, add 40 parts of water to dissolve, place in a 70°C water bath, and start 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, adding 20 parts of citric acid to 40 parts of water to prepare an aqueous solution, and then slowly dripping it into the solution of step S2. After the dripping is completed, the reaction is continued for 1 hour and then taken out to obtain the organic zirconium crosslinking agent 1.

[0047] According to the description of Example 4 in patent CN112142909A, after the modified polyacrylamide is synthesized and prepared into a 0.3% aqueous solution, the viscosity is measured by a six-speed rotary viscometer to be 30 mPa·s, and then 1% of the organic zirconium crosslinking agent 1 by volume is added to obtain a high viscosity gel, such as Figure 1 Add 20% of 40 / 70 mesh ceramsite to the high viscosity gel by mass ratio, stir evenly, and the proppant has no obvious sedimentation, as shown in the figure. Figure 2 shown.

[0048] Embodiment 2:

[0049] This embodiment is based on Embodiment 1, and differs from Embodiment 1 in that:

[0050] In the embodiment, zirconium hydroxide is used to provide zirconium ions, the polyhydroxy ligand is sodium gluconate, the alcohol amine ligand is triethanol, and the organic acid is lactic acid. The mass ratio of zirconium hydroxide to the polyhydroxy ligand, alcohol amine ligand, and organic acid is different from that in embodiment 1.

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

[0052] S1. Take 4 parts of zirconium hydroxide by mass and add them to a dry flask, add 20 parts of water to dissolve, place in a 70°C water bath, and start 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, adding 30 parts of lactic acid to 40 parts of water to prepare an aqueous solution, and then slowly dripping it into the solution of step S2. After the dripping is completed, the reaction is continued for 1 hour and then taken out to obtain the organic zirconium crosslinking agent 2.

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

[0056] Comparative Example 1:

[0057] This comparative example is based on Example 1, and differs from Example 1 in that no organic acid is used.

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

[0059] S1. Take 2 parts of zirconium oxychloride by mass and add them to a dry flask, add 40 parts of water to dissolve, place in a 70°C water bath, and start stirring;

[0060] S2. First add 10 parts of sodium lactobionate to the solution obtained in step S1, and after it is completely dissolved, add 10 parts of diethanolamine and continue stirring for 1 hour; thus, the organic zirconium crosslinking agent 3 is obtained.

[0061] According to the description of Example 4 in patent CN112142909A, after the modified polyacrylamide is synthesized, it is prepared into a 0.3% aqueous solution, and the viscosity is measured by a six-speed rotary viscometer to be 30 mPa·s. Then, 1% of the organic zirconium crosslinking agent 3 by volume of the solution is added, and there is no obvious change in the state of the solution, 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, and differs from Example 1 in that diethanolamine is not used.

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

[0065] S1. Take 2 parts of zirconium oxychloride by mass and add them to a dry flask, add 40 parts of water to dissolve, place in a 70°C water bath, and start stirring;

[0066] S2. First add 10 parts of sodium lactobionate to the solution obtained in step S1, and after it is completely dissolved, add 10 parts of citric acid and continue stirring for 1 hour; thus, the organic zirconium crosslinking agent 4 is obtained.

[0067] According to the description of Example 4 in patent CN112142909A, after the modified polyacrylamide is synthesized and prepared into a 0.3% aqueous solution, the viscosity is measured by a six-speed rotary viscometer to be 30 mPa·s. Then, 1% of the organic zirconium crosslinking agent 4 is added by volume, and white floccules appear in the solution state, and no gel is formed, 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, and differs from Example 1 in that sodium lactobionate is not used.

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

[0071] S1. Take 2 parts of zirconium oxychloride by mass and add them to a dry flask, add 40 parts of water to dissolve, place in a 70°C water bath, and start stirring;

[0072] S2. First, add 10 parts of diethanolamine to the solution obtained in step S1, and after it is completely dissolved, add 10 parts of citric acid, and continue stirring for 1 hour; thus, the organic zirconium crosslinking agent 5 is obtained.

[0073] According to the description of Example 4 in patent CN112142909A, after the modified polyacrylamide is synthesized and prepared into a 0.3% aqueous solution, the viscosity is measured by a six-speed rotary viscometer to be 30 mPa·s. Then, 1% of the organic zirconium crosslinking agent 5 by volume is added to the solution, and white floccules appear in the solution state, and no gel is formed, 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, and the difference from Example 1 is that the polyhydroxy ligand does not only use sodium lactobionate, but sodium lactobionate and sodium gluconate are mixed in a ratio of 1:1.

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

[0077] S1. Take 2 parts of zirconium oxychloride by mass and add them to a dry flask, add 40 parts of water to dissolve, place in a 70°C water bath, and start 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, adding 30 parts of lactic acid to 40 parts of water to prepare an aqueous solution, and then slowly dripping it into the solution of step S2. After the dripping is completed, the reaction is continued for 1 hour and then taken out to obtain the organic zirconium crosslinking agent 6.

[0080] According to the description of Example 4 in patent CN112142909A, after the modified polyacrylamide is synthesized and prepared into a 0.3% aqueous solution, the viscosity is measured by a six-speed rotary viscometer to be 30 mPa·s. Then, 1% of the organic zirconium crosslinking agent 6 by volume is added to the solution, and white floccules appear in the solution state, and no gel is formed, that is, the organic zirconium crosslinking agent prepared in this comparative example cannot increase the viscosity of the modified polyacrylamide.

[0081] By comparing the results of this comparative example with those of Example 1, it can be seen that:

[0082] The cross-linking effect of using only one polyhydroxy ligand, sodium lactobionate, cannot be achieved by cross-linking using two polyhydroxy ligands, sodium lactobionate and sodium gluconate.

[0083] Comparative Example 5:

[0084] This comparative example is based on Example 1, and differs from Example 1 in that the alcohol amine ligand does not only use diethanolamine, but diethanolamine and triethanolamine are mixed in a ratio of 1:1.

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

[0086] S1. Take 2 parts of zirconium oxychloride by mass and add them to a dry flask, add 40 parts of water to dissolve, place in a 70°C water bath, and start stirring;

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

[0088] S3, adding 30 parts of lactic acid to 40 parts of water to prepare an aqueous solution, and then slowly dripping it into the solution of step S2. After the dripping is completed, the reaction is continued for 1 hour and then taken out to obtain the organic zirconium crosslinking agent 7.

[0089] According to the description of Example 4 in patent CN112142909A, after the modified polyacrylamide is synthesized and prepared into a 0.3% aqueous solution, the viscosity is measured by a six-speed rotary viscometer to be 30 mPa·s. Then, 1% of the organic zirconium crosslinking agent 7 by volume is added to the solution, and white floccules appear in the solution state, and no gel is formed, that is, the organic zirconium crosslinking agent prepared in this comparative example cannot increase the viscosity of the modified polyacrylamide.

[0090] By comparing the results of this comparative example with those of Example 1, it can be seen that:

[0091] The cross-linking effect of using diethanolamine and polyhydroxy ligands cannot be achieved by using two alcohol amine ligands, diethanolamine and triethanolamine.

[0092] Comparative Example 6:

[0093] This comparative example is based on Example 1, and the difference from Example 1 is that the alcohol amine ligand does not use diethanolamine, but triethanolamine.

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

[0095] S1. Take 2 parts of zirconium oxychloride by mass and add them to a dry flask, add 40 parts of water to dissolve, place in a 70°C water bath, and start stirring;

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

[0097] S3, adding 20 parts of citric acid to 40 parts of water to prepare an aqueous solution, and then slowly dripping it into the solution of step S2. After the dripping is completed, the reaction is continued for 1 hour and then taken out to obtain the organic zirconium crosslinking agent 8.

[0098] According to the description of Example 4 in patent CN112142909A, after the modified polyacrylamide is synthesized and prepared into a 0.3% aqueous solution, the viscosity is measured by a six-speed rotary viscometer to be 30 mPa·s. Then, 1% of the organic zirconium crosslinking agent 8 by volume is added to the solution, and white floccules appear in the solution state, and no gel is formed, 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, and the difference from Example 1 is that the ratio of sodium lactobionate, diethanolamine and citric acid is changed.

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

[0102] S1. Take 2 parts of zirconium oxychloride by mass and add them to a dry flask, add 40 parts of water to dissolve, place in a 70°C water bath, and start stirring;

[0103] S2. First, 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, adding 30 parts of citric acid to 40 parts of water to prepare an aqueous solution, and then slowly dripping it into the solution of step S2. After the dripping is completed, the reaction is continued for 1 hour and then taken out to obtain the organic zirconium crosslinking agent 8.

[0105] According to the description of Example 4 in patent CN112142909A, after the modified polyacrylamide is synthesized and prepared into a 0.3% aqueous solution, the viscosity is measured by a six-speed rotary viscometer to be 30 mPa·s. Then, 1% of the organic zirconium crosslinking agent 9 by volume is added to the solution, and there is no obvious change in the state of the solution, 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, and the difference from Example 1 is that the ratio of sodium lactobionate, diethanolamine and citric acid is changed.

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

[0109] S1. Take 2 parts of zirconium oxychloride by mass and add them to a dry flask, add 40 parts of water to dissolve, place in a 70°C water bath, and start stirring;

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

[0111] S3, adding 20 parts of citric acid to 40 parts of water to prepare an aqueous solution, and then slowly dripping it into the solution of step S2. After the dripping is completed, the reaction is continued for 1 hour and then taken out to obtain the organic zirconium crosslinking agent 8.

[0112] According to the description of Example 4 in patent CN112142909A, after the modified polyacrylamide is synthesized and prepared into a 0.3% aqueous solution, the viscosity is measured by a six-speed rotary viscometer to be 30 mPa·s. Then, 1% of the organic zirconium crosslinking agent 10 by volume of the solution is added, and white floccules appear in the solution state, and no gel is formed, that is, the organic zirconium crosslinking agent prepared in this comparative example cannot increase the viscosity of the modified polyacrylamide.

[0113] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method 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 in the scope of protection of the present invention.

Claims

1. An organic zirconium crosslinking agent, characterized in that It is prepared by complexing zirconium salt or zirconium oxide with polyhydroxy ligand, alcohol amine ligand and organic acid.

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

3. An organic zirconium crosslinking agent according to claim 1, characterized in that: The polyhydroxy ligand is a polyhydroxy compound.

4. An organic zirconium crosslinking agent according to claim 3, characterized in that: The polyhydroxy compound is one or two of glucose, gluconic acid, sodium gluconate, sorbitol, lactol, lactose, lactitol, lactobionic acid, sodium lactobionic acid, galactose, galactobionic acid, sodium galactobionic acid and glycerol.

5. An organic zirconium crosslinking agent according to claim 1, characterized in that: The organic acid is a carboxylic acid type organic acid.

6. An organic zirconium crosslinking agent according to claim 5, 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.

7. An organic zirconium crosslinking agent according to claim 1, characterized in that: The alcoholamine ligand is one or two of diethanolamine, triethanolamine, N-methyldiethanolamine, isopropanolamine, phosphoethanolamine, diglycolamine, triisopropanolamine, diisopropanolamine, n-butylethanolamine, N-acetylethanolamine, tert-butyldiethanolamine and N-butyldiethanolamine.

8. An organic zirconium crosslinking agent according to claim 1, characterized in that: During the complexation reaction, the polyhydroxy ligand and the alcohol amine ligand are added in two steps, and the complexing agent with a smaller K value is added first, wherein K is the equilibrium constant of the complexation reaction.

9. An organic zirconium crosslinking agent according to claim 8, characterized in that: The polyhydroxy ligand is sodium lactobionate, and the alcohol amine ligand is diethanolamine; during the cross-linking reaction, sodium lactobionate is added first, and then diethanolamine is added.

10. An organic zirconium crosslinking agent according to claim 8, characterized in that: The polyhydroxy ligand is sodium gluconate, and the alcohol amine ligand is triethanolamine; during the cross-linking reaction, sodium gluconate is added first, and then triethanolamine is added.

11. The method for preparing the organic zirconium crosslinking agent according to any one of claims 1 to 10, characterized in that: The following steps are involved: S1. Add zirconium salt or zirconium oxide into water to form a transparent solution or suspension, and then heat it in a water bath; S2, adding a polyhydroxy ligand to the solution obtained in step S1, stirring for 1 to 2 hours, then adding an alcohol amine ligand, and continuing to stir for 1 to 8 hours; S3, preparing an aqueous solution of an organic acid, slowly dripping the aqueous solution into the solution of step S2, and continuing the reaction for 1 to 5 hours, then taking it out to obtain an organic zirconium crosslinking agent.

12. The preparation method according to claim 11, characterized in that: The temperature of the complexation reaction is 40-90°C.

13. Use of the organic zirconium crosslinking agent according to any one of claims 1 to 10 in the development of tight oil and gas, characterized in that: When used, the organic zirconium cross-linking agent described in any one of claims 1 to 10 is compounded with a modified polyacrylamide resistance reducing agent for use.

14. A gel, characterized in that: The organic zirconium cross-linking agent as described in any one of claims 1 to 10 is compounded with modified polyacrylamide.

15. A proppant comprising the gel of claim 14.

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