High-temperature-resistant organic titanium fracturing fluid cross-linking agent, preparation method and application thereof

Abstract

The application belongs to the field of fracturing fluid crosslinking agent, and particularly relates to a high-temperature-resistant organic titanium fracturing fluid crosslinking agent, a preparation method and application thereof. The high-temperature-resistant organic titanium fracturing fluid crosslinking agent comprises a crosslinking agent main body, the crosslinking agent main body is centered on Ti, organic groups are combined on the Ti central atom through covalent bonds and / or coordination bonds, and the organic groups comprise terminal hydroxyl organic carboxylic acid units, amino pyridine and diethanolamine units. The high-temperature-resistant organic titanium fracturing fluid crosslinking agent provided by the application further improves the temperature resistance of the crosslinking agent during use through the structural design of the above crosslinking agent, and the temperature resistance of the fracturing fluid after crosslinking can reach above 210 DEG C. In addition, the shear resistance of the fracturing fluid after crosslinking can be further improved, and the experimental shear resistance viscosity is greater than 170 mPa s. The above excellent temperature resistance and shear resistance can effectively solve the temperature resistance problem of the fracturing fluid during high-temperature reservoir fracturing construction, thereby improving the fracturing reconstruction effect of the reservoir.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of fracturing fluid crosslinking agent, and particularly relates to a high-temperature-resistant organic titanium fracturing fluid crosslinking agent as well as a preparation method and application thereof. BACKGROUND

[0002] With the substantial increase of the demand for crude oil in China, the fracturing reconstruction of oil wells has become an indispensable link in the process of crude oil production. The fracturing process is an important measure for increasing the production of oil and gas wells, and is widely used in various oil fields. The fracturing process is to use a high-pressure pump set on the ground to pump fracturing fluid into the formation at a rate much higher than the absorption capacity of the formation, so as to form a fracture in the formation and improve the flow conductivity of the oil and gas layer, thereby achieving the purpose of increasing production.

[0003] In the fracturing operation, the crosslinking agent plays an important role. Common crosslinking agents include organic boron crosslinking agents, organic aluminum crosslinking agents and organic titanium crosslinking agents, etc. Among them, the organic titanium crosslinking agent is a high-temperature fracturing fluid crosslinking agent, which can be crosslinked with hydroxymethyl cellulose, cassia gum, modified guanidine gum, tianfu and its derivatives, and various plant gums and polyacrylamide to form a gel. The organic titanium crosslinking agent also has the advantages of good water solubility, small dosage, convenient use, strong sand-carrying capacity, good temperature resistance, shear resistance, small formation damage, low friction, and adjustable crosslinking speed, and is a fracturing fluid crosslinking agent with superior performance.

[0004] A Chinese patent application with the application publication number CN103113874A discloses an organic titanium crosslinking agent, which is prepared by reacting butyl titanate, triethanolamine and glycerol at 60-80 DEG C. The fracturing fluid prepared by using the crosslinking agent and guar gum and konjac gum solution has a temperature resistance of above 80 DEG C. Although it can meet the development of most oil reservoirs, with the further development of oil reservoirs in recent years, the depth of oil wells is continuously increased, and the temperature of many oil reservoirs has reached above 130 DEG C. The poor temperature resistance of the crosslinking agent has become a key factor affecting the fracturing reconstruction effect of such oil reservoirs. SUMMARY

[0005] The present application aims to provide a high-temperature-resistant organic titanium fracturing fluid crosslinking agent to solve the problem that the temperature resistance of the existing organic titanium fracturing fluid crosslinking agent needs to be further improved.

[0006] The second object of the present application is to provide a preparation method of the high-temperature-resistant organic titanium fracturing fluid crosslinking agent to solve the above-mentioned problem.

[0007] The third object of the present application is to provide the application of the high-temperature-resistant organic titanium fracturing fluid crosslinking agent in the fracturing reconstruction of oil reservoirs or water wells to solve the problem that the temperature resistance and shear resistance of the existing fracturing fluid need to be improved.

[0008] In order to achieve the above objects, the technical scheme of the high-temperature-resistant organic titanium fracturing fluid crosslinking agent adopted by the present application is as follows:

[0009] The application provides a high-temperature-resistant organic titanium fracturing fluid cross-linking agent, which comprises a cross-linking agent body, the Ti is a central atom, and organic groups are combined on the Ti central atom through covalent bonds and / or coordination bonds, and the organic groups comprise end-hydroxyl organic carboxylic acid units, amino pyridine units and diethanol amine units.

[0010] The application provides a high-temperature-resistant organic titanium fracturing fluid cross-linking agent, which comprises a cross-linking agent body, the Ti is a central atom, and organic groups are combined on the Ti central atom through covalent bonds and / or coordination bonds, and the organic groups comprise end-hydroxyl organic carboxylic acid units, amino pyridine units and diethanol amine units.

[0011] Preferably, the organic groups comprise amide units formed after the end-hydroxyl organic carboxylic acid and the amino pyridine undergo an amidation reaction. The amide units are formed through the amidation reaction of the end-hydroxyl organic carboxylic acid and the amino pyridine, and are beneficial to improving the high-temperature resistance and shear resistance of the cross-linked fracturing fluid.

[0012] Preferably, the organic titanium fracturing fluid cross-linking agent further comprises a protective agent for delaying the cross-linking of the fracturing fluid, and the protective agent is a polyhydroxy compound. The polyhydroxy compound is a small molecule substance containing multiple hydroxyl groups, for example, glycerol and the like. The protective agent can temporarily prevent the entire molecule from reacting with the hydroxyl groups of the guar gum, and has the characteristic of delaying cross-linking.

[0013] Further preferably, the high-temperature-resistant organic titanium fracturing fluid cross-linking agent has a temperature resistance of above 210 DEG C when used. The temperature resistance of above 210 DEG C when used can meet the fracturing construction requirements of most high-temperature reservoirs.

[0014] A preparation method of a high-temperature-resistant organic titanium fracturing fluid cross-linking agent comprises the following steps: titanium source, end-hydroxyl organic carboxylic acid, diethanol amine and p-amino pyridine are reacted in water at 50-70 DEG C.

[0015] The preparation method of the high-temperature-resistant organic titanium fracturing fluid cross-linking agent has the advantages of no product separation, simple and reasonable process, wide raw material sources, no pollution, environmental friendliness and suitability for large-scale industrial production.

[0016] Preferably, the titanium source is titanium tetrachloride, the end-hydroxyl organic carboxylic acid is hydroxyacetic acid or 3-hydroxypropionic acid, and the mass ratio of the titanium source, the end-hydroxyl organic carboxylic acid, diethanol amine and p-amino pyridine is 1:1.9-2.4:1.1-1.6:0.4-0.6. The above raw materials are used for reaction in the above ratio, so that the organic titanium fracturing fluid cross-linking agent with good high-temperature resistance and shear resistance can be obtained.

[0017] Further preferably, the mass ratio of the titanium source and water is 1:4-5. Controlling the amount of water in the above ratio can maintain the reaction system at a suitable viscosity and promote efficient reaction.

[0018] Preferably, the reaction comprises a first reaction of mixing the titanium source, water and the hydroxyl-terminated organic carboxylic acid, followed by a second reaction of adding diethanolamine and p-aminopyridine; the first reaction is carried out at pH=6-7, the reaction temperature is 50-60℃, and the time is 1-2h; the reaction temperature of the second reaction is 60-70℃, and the time is 2-3h. Through the above continuous reaction process, the hydroxyl-terminated organic carboxylic acid is preferentially reacted, and the structure of the crosslinking agent is controlled to a certain extent, and the high-temperature resistance and other properties of the crosslinking agent are optimized. The first reaction and the second reaction are carried out under the above conditions, and the reaction efficiency is high and the reaction effect is good.

[0019] Further preferably, the reaction is carried out in water at 50-70℃, and then glycerol is added for mixing, and the mass ratio of the titanium source and glycerol is 1:1.1-1.6. After adding glycerol, the crosslinking delay time of the fracturing fluid crosslinking agent is greater than 400s, thereby realizing the delayed crosslinking of the fracturing fluid crosslinking agent.

[0020] The application of the above high-temperature-resistant organic titanium fracturing fluid crosslinking agent in the fracturing reconstruction of oil reservoir oil wells or water wells.

[0021] When the high-temperature-resistant organic titanium fracturing fluid crosslinking agent is applied in the fracturing reconstruction of oil reservoir oil wells or water wells, especially when it is applied in crosslinked polyacrylamide, it has obvious advantages in temperature resistance, shear resistance and price, and can effectively improve the fracturing reconstruction effect of oil reservoir oil wells or water wells. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is a physical picture of the G8 crosslinking agent after crosslinking in the experimental examples of the present application;

[0023] Figure 2 It is the rheological curve of the fracturing fluid after the G8 crosslinking agent is crosslinked in the experimental examples of the present application. DETAILED DESCRIPTION

[0024] The purpose of the present application is to provide a high-temperature-resistant and shear-resistant organic titanium fracturing fluid crosslinking agent, which has a temperature resistance of more than 210℃ and a shear viscosity of more than 170mPa·s.

[0025] The organic titanium fracturing fluid crosslinking agent is obtained by dehydration reaction of water, a titanium source, a hydroxyl-terminated organic carboxylic acid, diethanolamine and p-aminopyridine raw materials. Specifically, the target product can be obtained by using a continuous reaction method without separation and other post-treatment.

[0026] The organic titanium fracturing fluid crosslinking agent of the present application is preferably prepared in the following manner: first, mix the titanium source, water and hydroxyl-terminated organic carboxylic acid, then perform a first reaction, and then add diethanolamine and p-aminopyridine to perform a second reaction.

[0027] The first reaction is performed at pH = 6-7, the reaction temperature is 50-60°C, and the time is 1-2h; the reaction temperature of the second reaction is 60-70°C, and the time is 2-3h.

[0028] The fracturing fluid crosslinking agent obtained according to the above reaction can contain each of the following substances of the following structural formula:

[0029]

[0030]

[0031] In the above formula (1)-(4), the solid line represents a covalent bond connection relationship, and the arrow represents a coordination bond connection relationship.

[0032] The hydroxyl-terminated organic carboxylic acid is preferably hydroxyacetic acid or 3-hydroxypropionic acid. The hydroxyl-terminated organic carboxylic acid unit is a corresponding part formed after the hydroxyl and / or carboxyl on the hydroxyl-terminated organic carboxylic acid and the hydroxyl on the Ti atom undergo dehydration reaction. The diethanolamine unit is a corresponding part formed after the alcohol hydroxyl on the diethanolamine and the hydroxyl on the Ti atom undergo dehydration reaction. The hydroxyl on the Ti atom is formed after the titanium source is hydrolyzed, and the titanium source is preferably titanium tetrachloride.

[0033] The above reaction can obtain a crosslinking agent with titanium as the central atom and hydroxyl-terminated organic carboxylic acid as the organic binding unit. The mechanism of the entire crosslinking agent is relatively complex, and the main principle is that the outermost electron configuration of the titanium atom is 3d 2 4s 2 After adding diethanolamine, the outermost layer of the titanium atom undergoes d 2 sp 3 inequality hybridization, and there are 6 spatial orbitals in total. The titanium atom provides 4 electrons, each of the 4 3-hydroxypropionic acid molecules provides one electron, and a covalent bond occupies 4 orbitals. The nitrogen atom in diethanolamine has a lone pair of electrons, and 2 diethanolamines combine with the empty orbitals of the titanium atom to occupy the remaining 2 orbitals, forming a stable ligand. The NH2 in aminopyridine can form an amide structure with carboxylic acid, and the pyridine ring structure is stable and not prone to chemical reaction, which protects the entire molecule.

[0034] The addition of the polyhydroxy compound can further protect the entire molecule from temporarily reacting with the hydroxyl groups of the guar gum, thereby delaying crosslinking. Before the polyhydroxy compound is added, the aforementioned reaction raw materials have been substantially completely reacted with the hydroxyl groups on the Ti, and the polyhydroxy compound added can continue to provide hydroxyl groups to continue to protect the titanium atoms from being exposed, thereby achieving a delaying effect. The polyhydroxy compound is preferably glycerol, which contains three hydroxyl groups. The glycerol is added last, and after being added, the reaction is stirred for 0.5-1 h.

[0035] The implementation process of the present application will be described in detail below in conjunction with specific examples.

[0036] First, a specific example of the high-temperature-resistant organic titanium fracturing fluid crosslinking agent and a preparation method thereof according to the present application

[0037] Example 1

[0038] The high-temperature-resistant organic titanium fracturing fluid crosslinking agent of this example is mainly composed of a crosslinking agent main body, water, and glycerol. The crosslinking agent main body is an organic titanium formed by Ti and a plurality of organic groups through covalent bonds and coordination bonds. The organic groups contain end-hydroxyl organic carboxylic acid units, amino pyridine units, diethanolamine units, and amide units formed after the end-hydroxyl organic carboxylic acid and amino pyridine undergo an amidation reaction. The crosslinking agent main body contains each substance corresponding to the structural formulas of formulas (1)-(4).

[0039] The preparation method of the high-temperature-resistant organic titanium fracturing fluid crosslinking agent of this example includes the following steps:

[0040] (1) 100 g of titanium tetrachloride, 500 g of water, and 190 g of 3-hydroxypropionic acid are added to a reactor, and after being fully stirred, the temperature is raised to 50°C. A 2 mol / L NaOH solution is used to adjust the pH value to 6-7, and the reaction is carried out at a constant temperature for 1 h;

[0041] (2) 110 g of diethanolamine and 40 g of p-aminopyridine are added, the temperature is raised to 60°C, and the stirring reaction is continued for 2 h at a stirring speed of 300 rpm;

[0042] (3) 110 g of glycerol is added, and stirring is carried out at the temperature of step (2) for 0.5 h to obtain the fracturing fluid crosslinking agent G1.

[0043] Example 2

[0044] The preparation method of the high-temperature-resistant organic titanium fracturing fluid crosslinking agent of this example includes the following steps:

[0045] (1) 100 g of titanium tetrachloride, 480 g of water, and 200 g of 3-hydroxypropionic acid are added to a reactor, and after being fully stirred, the temperature is raised to 55°C. A 2 mol / L NaOH solution is used to adjust the pH value to 6-7, and the reaction is carried out at a constant temperature for 1.5 h;

[0046] (2) Add 120 g of diethanolamine and 44 g of p-aminopyridine, and heat to 62°C. Continue stirring at 400 rpm for 3 h;

[0047] (3) Add 120 g of glycerol, and stir at the temperature of step (2) for 0.7 h to obtain the crosslinking agent G2 of the fracturing fluid.

[0048] Example 3

[0049] The preparation method of the high-temperature-resistant organic titanium fracturing fluid crosslinking agent of the present example comprises the following steps:

[0050] (1) Add 100 g of titanium tetrachloride, 460 g of water, and 210 g of 3-hydroxypropionic acid into a reactor, and heat to 60°C after stirring. Adjust the pH value to 6-7 with a 2 mol / L NaOH solution, and react at constant temperature for 2 h;

[0051] (2) Add 130 g of diethanolamine and 48 g of p-aminopyridine, and heat to 70°C. Continue stirring at 500 rpm for 2.2 h;

[0052] (3) Add 130 g of glycerol, and stir at the temperature of step (2) for 1 h to obtain the crosslinking agent G3 of the fracturing fluid.

[0053] Example 4

[0054] The preparation method of the high-temperature-resistant organic titanium fracturing fluid crosslinking agent of the present example comprises the following steps:

[0055] (1) Add 100 g of titanium tetrachloride, 440 g of water, and 220 g of 3-hydroxypropionic acid into a reactor, and heat to 52°C after stirring. Adjust the pH value to 6-7 with a 2 mol / L NaOH solution, and react at constant temperature for 1.2 h;

[0056] (2) Add 140 g of diethanolamine and 52 g of p-aminopyridine, and heat to 65°C. Continue stirring at 450 rpm for 2.4 h;

[0057] (3) Add 140 g of glycerol, and stir at the temperature of step (2) for 1 h to obtain the crosslinking agent G4 of the fracturing fluid.

[0058] Example 5

[0059] The preparation method of the high-temperature-resistant organic titanium fracturing fluid crosslinking agent of the present example comprises the following steps:

[0060] (1) Add 100 g of titanium tetrachloride, 420 g of water, and 230 g of 3-hydroxypropionic acid into a reactor, and heat to 58°C after stirring. Adjust the pH value to 6-7 with a 2 mol / L NaOH solution, and react at constant temperature for 1.6 h;

[0061] (2) Add 150 g of diethanolamine and 56 g of p-aminopyridine, and heat to 68°C. Continue stirring at 350 rpm for 2.6 h;

[0062] (3) Add 150 g of glycerol, and stir at the temperature of step (2) for 0.6 h to obtain the fracturing fluid crosslinking agent G5.

[0063] Example 6

[0064] The preparation method of the high-temperature-resistant organic titanium fracturing fluid crosslinking agent of the present example comprises the following steps:

[0065] (1) Add 100 g of titanium tetrachloride, 400 g of water, and 240 g of 3-hydroxypropionic acid into a reactor, and heat to 53°C after stirring. Adjust the pH value to 6-7 with a 2 mol / L NaOH solution, and react at constant temperature for 1.8 h;

[0066] (2) Add 160 g of diethanolamine and 60 g of p-aminopyridine, and heat to 66°C. Continue stirring at 400 rpm for 2.8 h;

[0067] (3) Add 160 g of glycerol, and stir at the temperature of step (2) for 0.8 h to obtain the fracturing fluid crosslinking agent G6.

[0068] Example 7

[0069] The preparation method of the high-temperature-resistant organic titanium fracturing fluid crosslinking agent of the present example comprises the following steps:

[0070] (1) Add 100 g of titanium tetrachloride, 450 g of water, and 200 g of 3-hydroxypropionic acid into a reactor, and heat to 55°C after stirring. Adjust the pH value to 6-7 with a 2 mol / L NaOH solution, and react at constant temperature for 1.5 h;

[0071] (2) Add 120 g of diethanolamine and 50 g of p-aminopyridine, and heat to 65°C. Continue stirring at 450 rpm for 2.5 h;

[0072] (3) Add 130 g of glycerol, and stir at the temperature of step (2) for 0.5 h to obtain the fracturing fluid crosslinking agent G7.

[0073] Example 8

[0074] The preparation method of the high-temperature-resistant organic titanium fracturing fluid crosslinking agent of the present example comprises the following steps:

[0075] (1) Add 100 g of titanium tetrachloride, 420 g of water, and 210 g of 3-hydroxypropionic acid into a reactor, and heat to 52°C after stirring. Adjust the pH value to 6-7 with a 2 mol / L NaOH solution, and react at constant temperature for 2 h;

[0076] (2) Add 130g of diethanolamine and 45g of p-aminopyridine, heat to 68℃, and continue stirring for 2.6h at a stirring speed of 400rpm.

[0077] (3) Add 120g of glycerol and stir for 1h at the temperature in step (2) to obtain fracturing fluid crosslinking agent G8.

[0078] II. Application of High-Temperature Resistant Organic Titanium Fracturing Fluid Crosslinking Agent in Experimental Examples

[0079] Fracturing fluids were prepared by mixing the crosslinking agent and polyacrylamide solution from each embodiment, and then the delayed crosslinking time, temperature resistance, and temperature and shear resistance were evaluated.

[0080] 1. Delayed crosslinking experiment:

[0081] Dissolve 5g of polyacrylamide in 1000ml of water. Pour 400mL of the solution into the mixing cup of the Wu Yin mixer. Adjust the voltage to keep the mixer running until the bottom of the vortex is visible above the top of the mixer. Take 2ml of the crosslinking agent solution and pour it into the mixing cup of the continuously stirring mixer. Use a stopwatch to record the time required from the time the crosslinking agent is poured in until the vortex disappears and the liquid surface slightly bulges. This time is the crosslinking time. A comparative experiment was conducted using the commercially available organoaluminum crosslinking agent BHJ-106. The test results are shown in Table 1.

[0082] The cross-linked fracturing fluid was poured into a beaker and subjected to a hanging test; it was found to be able to hang completely. Figure 1 A photograph of the crosslinked fracturing fluid crosslinking agent G8 of the present invention is shown. From... Figure 1 It can be seen that the fracturing fluid crosslinking agent of the present invention exhibits good adhesion after crosslinking polyacrylamide.

[0083] 2. Evaluation of temperature resistance

[0084] Fracturing fluid crosslinking agents G1 to G8 were prepared according to the delayed crosslinking experiment (at the time of completion of crosslinking agent addition). The samples were then added to a MARS-Ⅲ high-temperature, high-pressure rotational rheometer, with a heating rate set at 3.0℃ ± 0.2℃. The samples were heated simultaneously at 100s... -1 The sample was continuously sheared at a certain shear rate, and the apparent viscosity was tested. The apparent viscosity of the sample decreased with increasing temperature and shear. The temperature indicated when the apparent viscosity dropped to 50 mPa·s was the temperature resistance. A comparative experiment was conducted using commercially available crosslinking agent BHJ-106. The test results are shown in Table 1.

[0085] 3. Evaluation of temperature and shear resistance

[0086] The fracturing fluid crosslinking agent G1-G8 was configured into fracturing fluid (crosslinking agent plus Biji timing) according to the delayed crosslinking experiment part, and was added into a MARS-III high temperature and high pressure rotary rheometer, the temperature rising rate was set to 3.0℃±0.2℃, the sample was heated to 120℃, then was continuously sheared at a shear rate of 100s -1 The apparent viscosity value was read, a commercially available crosslinking agent BHJ-106 was used for a comparative experiment, and the test results are shown in Table 1. Among them, the rheological curve of the fracturing fluid after crosslinking of G8 is shown in Figure 2 , wherein the red curve is the temperature curve, and the blue curve is the apparent viscosity curve.

[0087] Table 1 shows the delayed crosslinking time, temperature resistance and temperature and shear resistance test results

[0088]

[0089]

[0090] As can be seen from Table 1, the delayed time of the fracturing fluid crosslinking agent G1-G8 is 412s, 442s, 457s, 480s, 520s, 494s, 515s and 536s respectively, wherein the longest delayed time of G8 is 536s, and the delayed time is greater than 400s; and the delayed time of BHJ-106 is 68s, which is obviously lower than that of the crosslinking agent.

[0091] The temperature resistance of the fracturing fluid crosslinking agent G1-G8 is 214℃, 220℃, 226℃, 229℃, 238℃, 228℃, 240℃ and 245℃ respectively, and the temperature resistance is greater than 210℃, wherein the highest temperature resistance of G8 reaches 245℃; and the temperature resistance of BHJ-106 is 137℃, which is obviously lower than that of the present application, indicating that the fracturing fluid crosslinking agent has good temperature resistance.

[0092] The shear resistance viscosity of the fracturing fluid crosslinking agent G1-G8 is 178mPa·s, 183mPa·s, 187mPa·s, 191mPa·s, 192mPa·s, 190mPa·s, 193mPa·s and 198mPa·s respectively, which is greater than 170mPa·s, wherein the shear resistance viscosity of G8 is the largest, reaching 198mPa·s; and the shear resistance viscosity of BHJ-106 is 68mPa·s, indicating that the shear resistance of the fracturing fluid crosslinking agent is obviously stronger than that of BHJ-106.

[0093] From the above experiments, it can be seen that the organic titanium fracturing fluid crosslinking agent has the following characteristics:

[0094] (1) The raw materials of the fracturing fluid crosslinking agent are widely available, and the synthesis process is simple;

[0095] (2) The fracturing fluid cross-linking agent reaction process of the present application does not need separation, and the target product can be obtained by continuous reaction, with a yield of 100%, and all the products can be used as the cross-linking of the fracturing fluid;

[0096] (3) The fracturing fluid cross-linking agent of the present application has a cross-linking delay time of greater than 400s;

[0097] (4) The fracturing fluid cross-linking agent of the present application has the properties of temperature resistance and shear resistance after cross-linking, the temperature resistance of the cross-linked fracturing fluid can reach above 210℃, the shear viscosity is greater than 170mPa·s, and the problem of temperature resistance of the fracturing fluid in high-temperature reservoirs (210℃) can be solved. Therefore, the present application can be widely applied in the fracturing reconstruction of oil or water wells.

Claims

1. A high temperature resistant organic titanium fracturing fluid crosslinking agent, characterized in that, The crosslinking agent body is centered on Ti, and organic groups are combined on the Ti central atom by covalent bonds and / or coordination bonds, the organic groups including end hydroxyl organic carboxylic acid units, amino pyridine and diethanol amine units.

2. The high-temperature resistant organic titanium fracturing fluid crosslinking agent of claim 1, characterized in that, The organic groups include end hydroxyl organic carboxylic acid, amino pyridine amide units formed after amide reaction.

3. The high temperature resistant organic titanium fracturing fluid crosslinking agent of claim 1, wherein, The organic titanium fracturing fluid crosslinking agent further includes a protective agent for delaying fracturing fluid crosslinking, the protective agent being a polyhydroxy compound.

4. The high-temperature resistant organic titanium fracturing fluid crosslinking agent according to any one of claims 1-3, characterized in that, The temperature resistance of the high-temperature-resistant organic titanium fracturing fluid crosslinking agent is above 210℃.

5. A method for preparing a high-temperature-resistant organic titanium fracturing fluid crosslinking agent, characterized in that, The method comprises the following steps: The titanium source, end hydroxyl organic carboxylic acid, diethanol amine and p-aminopyridine are reacted in water at 50-70℃.

6. The method for preparing high temperature resistant organic titanium fracturing fluid crosslinking agent according to claim 5, characterized in that, The titanium source is titanium tetrachloride, and the end hydroxyl organic carboxylic acid is hydroxyacetic acid or 3-hydroxypropionic acid; the mass ratio of the titanium source, end hydroxyl organic carboxylic acid, diethanol amine and p-aminopyridine is 1:1.9-2.4:1.1-1.6:0.4-0.

6.

7. The method for preparing high temperature resistant organic titanium fracturing fluid crosslinking agent according to claim 6, characterized in that, The mass ratio of the titanium source and water is 1:4-5.

8. The method for preparing high temperature resistant organic titanium fracturing fluid crosslinking agent according to claim 5, characterized in that, The reaction comprises first mixing the titanium source, water and end hydroxyl organic carboxylic acid to perform a first reaction, and then adding diethanol amine and p-aminopyridine to perform a second reaction; the first reaction is performed under the condition of pH=6-7, the reaction temperature is 50-60℃, and the reaction time is 1-2h; the reaction temperature of the second reaction is 60-70℃, and the reaction time is 2-3h.

9. The method for preparing the high-temperature-resistant organic titanium fracturing fluid crosslinking agent according to any one of claims 5-8, characterized in that, The titanium source and glycerol are mixed after the reaction in water at 50-70℃, and the mass ratio of the titanium source and glycerol is 1:1.1-1.

6.

10. Application of the high-temperature-resistant organic titanium fracturing fluid crosslinking agent in claims 1-4 to fracturing reconstruction of oil reservoir oil wells or water wells.

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