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

Abstract

The invention belongs to the field of fracturing fluid cross-linking agents, and particularly relates to a high-temperature-resistant organic titanium fracturing fluid cross-linking agent and a preparation method and application thereof. The high-temperature-resistant organic titanium fracturing fluid cross-linking agent comprises a cross-linking agent main body, the cross-linking agent main body takes Ti as a central atom, an organic group is bonded on the Ti central atom through a covalent bond and / or a coordinate bond, and the organic group comprises a hydroxyl-terminated organic carboxylic acid unit, aminopyridine and a diethanol amine unit. According to the high-temperature-resistant organic titanium fracturing fluid cross-linking agent provided by the invention, through the structural design of the cross-linking agent, the temperature resistance of the cross-linking agent during use is further improved, and the cross-linked fracturing fluid can resist the temperature of 210 DEG C or above. In addition, the anti-shearing performance of the fracturing fluid after crosslinking can be further improved, and the experimental anti-shearing viscosity is greater than 170mPa. S. The excellent temperature resistance and shear resistance can effectively solve the problem of temperature resistance of the fracturing fluid during fracturing construction of high-temperature reservoirs, so that the fracturing transformation effect of the reservoirs is improved.

Description

Technical Field

[0001] The invention belongs to the field of fracturing fluid crosslinking agents, and in particular relates to a high-temperature resistant organic titanium fracturing fluid crosslinking agent and a preparation method and application thereof. Background Art

[0002] With the substantial increase in my country's demand for crude oil, the fracturing of oil wells has become an indispensable part of the crude oil production process. Fracturing technology is an important measure to increase the production of oil and gas wells, and is widely used in various oil fields. It uses a ground high-pressure pump group to pump fracturing fluid into the formation at a rate that greatly exceeds the absorption capacity of the formation, forming cracks in the formation and improving the conductivity of the oil and gas layer, thereby achieving the purpose of increasing production.

[0003] In fracturing construction, crosslinking agents play a pivotal role. Common crosslinking agents include organic boron crosslinking agents, organic aluminum crosslinking agents, and organic titanium crosslinking agents. Among them, organic titanium crosslinking agents are a high-temperature fracturing fluid crosslinking agent that can crosslink with various plant gums such as hydroxymethyl cellulose, fennel gum, modified guar gum, Tianfu and its derivatives, and polyacrylamide to form a gel. Organic titanium crosslinking agents also have the advantages of good water solubility, small dosage, easy use, strong sand carrying capacity, good temperature resistance, shear resistance, little damage to the formation, low friction, and adjustable crosslinking speed. It is a fracturing fluid crosslinking agent with superior performance.

[0004] The Chinese invention patent application with application publication number CN103113874A discloses an organic titanium crosslinking agent, which is made by reacting butyl titanate, triethanolamine and glycerol at 60-80° C. The temperature resistance of the fracturing fluid made of the crosslinking agent and guar gum and konjac gum solution reaches above 80° 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 has been continuously increased, and the temperature of many oil reservoirs has reached above 130° C. The poor temperature resistance of the crosslinking agent has become the key to affecting the fracturing transformation effect of such oil reservoirs. Summary of the invention

[0005] The purpose of the present invention is 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 invention is to provide a method for preparing the above-mentioned high temperature resistant organic titanium fracturing fluid cross-linking agent to solve the above-mentioned problems.

[0007] The third object of the present invention is to provide the application of the above-mentioned high temperature resistant organic titanium fracturing fluid crosslinking agent in the fracturing transformation of oil wells or water wells in oil reservoirs, so as 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 objectives, the technical solution of the high temperature resistant organic titanium fracturing fluid crosslinking agent adopted by the present invention is:

[0009] A high temperature resistant organic titanium fracturing fluid crosslinker comprises a crosslinker main body, wherein the crosslinker main body takes Ti as a central atom, an organic group is bonded to the Ti central atom through a covalent bond and / or a coordination bond, and the organic group comprises a terminal hydroxyl organic carboxylic acid unit, an aminopyridine and a diethanolamine unit.

[0010] The high temperature resistant organic titanium fracturing fluid crosslinker provided by the present invention further improves the temperature resistance of the crosslinker during use through the structural design of the crosslinker, and the temperature resistance of the fracturing fluid after crosslinking can reach above 210°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 170mPa·s. The above excellent heat resistance and shear resistance can effectively solve the temperature resistance problem of the fracturing fluid during the fracturing construction of high temperature reservoirs, thereby improving the fracturing transformation effect of such reservoirs.

[0011] Preferably, the organic group includes an amidation unit formed by amidation reaction of a terminal hydroxyl organic carboxylic acid and aminopyridine. The above amidation unit is formed by amidation reaction of a terminal hydroxyl organic carboxylic acid and aminopyridine, which is beneficial to improving the high temperature resistance and shear resistance of the cross-linked fracturing fluid.

[0012] Preferably, the organic titanium fracturing fluid crosslinking agent also includes a protective agent for delaying the crosslinking of the fracturing fluid, and the protective agent is a polyhydroxy compound. The polyhydroxy compound is a small molecule substance containing multiple hydroxyl groups, such as glycerol. The protective agent can protect the entire molecule from temporarily reacting with the hydroxyl group of guar gum, and has the characteristic of delayed crosslinking.

[0013] Further preferably, the temperature resistance of the high temperature resistant organic titanium fracturing fluid cross-linking agent is above 210° C. When used, the temperature resistance is guaranteed to reach above 210° C., which can meet the fracturing construction requirements of most high temperature reservoirs.

[0014] A method for preparing a high temperature resistant organic titanium fracturing fluid crosslinking agent comprises the following steps: a titanium source, a terminal hydroxyl organic carboxylic acid, diethanolamine and p-aminopyridine react in water at 50-70 DEG C.

[0015] The preparation method of the high temperature resistant organic titanium fracturing fluid cross-linking agent of the present invention does not require product separation and has a reasonable and simple process; the raw material source is wide, no pollution is generated, the environment is friendly, and the method is suitable for large-scale industrial production.

[0016] Preferably, the titanium source is titanium tetrachloride, the terminal hydroxy organic carboxylic acid is glycolic acid or 3-hydroxypropionic acid; the mass ratio of the titanium source, terminal hydroxy organic carboxylic acid, diethanolamine and aminopyridine is 1:1.9-2.4:1.1-1.6:0.4-0.6. The above raw materials are used to react according to the above ratio to ensure that an organic titanium fracturing fluid crosslinking agent with good high temperature resistance and shear resistance is obtained.

[0017] More preferably, the mass ratio of the titanium source to water is 1:4 to 5. Controlling the amount of water within the above ratio can maintain the reaction system at an appropriate viscosity and promote efficient reaction.

[0018] Preferably, the reaction includes first mixing a titanium source, water, and a terminal hydroxyl organic carboxylic acid for a first reaction, and then adding diethanolamine and p-aminopyridine for a second reaction; the first reaction is carried out under the condition of 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. Through the above continuous reaction process, the terminal hydroxyl organic carboxylic acid can be preferentially reacted, the structural regulation of the cross-linking agent can be achieved to a certain extent, and the various properties of the cross-linking agent such as high temperature resistance are optimized. The first reaction and the second reaction are carried out under the above conditions, with high reaction efficiency and good reaction effect.

[0019] Further preferably, after the reaction is carried out in water at 50-70° C., glycerol is added and mixed, and the mass ratio of the titanium source to the glycerol is 1:1.1-1.6. After the addition of glycerol, the cross-linking delay time of the fracturing fluid cross-linking agent can be greater than 400s, thereby achieving delayed cross-linking of the fracturing fluid cross-linking agent.

[0020] The application of the high temperature resistant organic titanium fracturing fluid cross-linking agent in the fracturing transformation of oil wells or water wells in oil reservoirs.

[0021] When the high temperature resistant organic titanium fracturing fluid cross-linking agent is used in the fracturing transformation of oil wells or water wells in oil reservoirs, especially when it is used in cross-linked polyacrylamide, it has obvious advantages in temperature resistance, shear resistance, price, etc., and can effectively improve the fracturing transformation effect of oil wells or water wells in oil reservoirs. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a physical picture of the cross-linked G8 cross-linker in the experimental example of the present invention;

[0023] Figure 2 This is the rheological curve of the fracturing fluid after cross-linking with the G8 cross-linking agent in the experimental example of the present invention. DETAILED DESCRIPTION

[0024] The object of the present invention is to provide a high temperature resistant and shear resistant organic titanium fracturing fluid crosslinking agent, which has a temperature resistance of over 210°C and a shear resistant viscosity of over 170 mPa·s.

[0025] The organic titanium fracturing fluid crosslinking agent is obtained by dehydrating water, titanium source, terminal hydroxyl organic carboxylic acid, diethanolamine and aminopyridine raw materials. Specifically, a continuous reaction mode can be adopted to obtain the target product without separation and other post-processing.

[0026] The organic titanium fracturing fluid crosslinking agent of the present invention is preferably prepared in the following manner: firstly, a titanium source, water, and a terminal hydroxyl organic carboxylic acid are mixed and then subjected to a first reaction, and then diethanolamine and p-aminopyridine are added to conduct a second reaction.

[0027] The first reaction is carried out under the condition of 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 cross-linking agent obtained according to the above reaction may contain the following substances:

[0029]

[0030]

[0031] In the above formulae (1) to (4), the solid lines represent covalent bond relationships, and the arrows represent coordinate bond relationships.

[0032] The terminal hydroxy organic carboxylic acid is preferably glycolic acid or 3-hydroxypropionic acid. The terminal hydroxy organic carboxylic acid unit is the corresponding part formed by the dehydration reaction of the hydroxyl and / or carboxyl groups on the terminal hydroxy organic carboxylic acid and the hydroxyl groups on the Ti atom. The diethanolamine unit is the corresponding part formed by the dehydration reaction of the alcoholic hydroxyl groups on the diethanolamine and the hydroxyl groups on the Ti atom. The hydroxyl groups on the Ti atom are formed by the hydrolysis of a titanium source, and the titanium source is preferably titanium tetrachloride.

[0033] The above reaction can be used to obtain a crosslinker with titanium as the central atom and terminal hydroxyl organic carboxylic acid as the organic bonding unit. The mechanism of action of the entire crosslinker is relatively complex, among which the main principle is: the outermost electron configuration of the titanium atom is 3d 2 4s 2 After adding diethanolamine, the outermost layer of titanium atoms undergoes d 2 sp 3 Asymmetric hybridization, with a total of 6 space orbitals, the titanium atom provides 4 electrons, and the 4 3-hydroxypropionic acid molecules each provide an electron, forming a covalent bond to occupy 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 to form 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 reactions, which protects the entire molecule.

[0034] Adding polyols can further protect the entire molecule from temporarily reacting with the hydroxyl groups of guar gum, thus delaying crosslinking. Before adding polyols, the aforementioned reaction raw materials have basically reacted completely with Ti (the hydroxyl groups on it), and the added polyols can continue to provide hydroxyl groups and continue to protect the titanium atoms from being exposed, thereby delaying the reaction. The polyol is preferably glycerol, which contains three hydroxyl groups. Glycerol is added last, and the reaction is stirred for 0.5 to 1 hour after the addition is completed.

[0035] The implementation process of the present invention is described in detail below in conjunction with specific embodiments.

[0036] 1. Specific embodiments of the high temperature resistant organic titanium fracturing fluid crosslinking agent and its preparation method of the present invention

[0037] Example 1

[0038] The high temperature resistant organic titanium fracturing fluid crosslinker of this embodiment is mainly composed of a crosslinker main body, water and glycerol, wherein the crosslinker main body is an organic titanium formed by Ti and a variety of organic groups through covalent bonds and coordination bonds, and the organic groups contain terminal hydroxyl organic carboxylic acid units, aminopyridine, diethanolamine units and amidation units formed by amidation reaction of terminal hydroxyl organic carboxylic acid and aminopyridine. The crosslinker main body contains various substances corresponding to the structural formulas of formula (1) to formula (4).

[0039] The preparation method of the high temperature resistant organic titanium fracturing fluid cross-linking agent of this embodiment comprises the following steps:

[0040] (1) Add 100 g of titanium tetrachloride, 500 g of water, and 190 g of 3-hydroxypropionic acid into a reactor, stir thoroughly, heat to 50° C., adjust the pH value to 6-7 with 2 mol / L NaOH solution, and react at constant temperature for 1 hour;

[0041] (2) Add 110 g of diethanolamine and 40 g of p-aminopyridine, raise the temperature to 60°C, and continue stirring for 2 h at a stirring speed of 300 rpm;

[0042] (3) Add 110 g of glycerol and stir for 0.5 h at the temperature of step (2) to obtain fracturing fluid crosslinking agent G1.

[0043] Example 2

[0044] The preparation method of the high temperature resistant organic titanium fracturing fluid cross-linking agent of this embodiment comprises the following steps:

[0045] (1) Add 100 g of titanium tetrachloride, 480 g of water, and 200 g of 3-hydroxypropionic acid into a reactor, stir thoroughly, heat to 55° C., adjust the pH value to 6-7 with 2 mol / L NaOH solution, and react at constant temperature for 1.5 h;

[0046] (2) Add 120 g of diethanolamine and 44 g of p-aminopyridine, raise the temperature to 62°C, and continue stirring for 3 h at a stirring speed of 400 rpm;

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

[0048] Example 3

[0049] The preparation method of the high temperature resistant organic titanium fracturing fluid cross-linking agent of this embodiment 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, stir thoroughly, heat to 60° C., adjust the pH value to 6-7 with 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, raise the temperature to 70°C, and continue stirring for 2.2 h at a stirring speed of 500 rpm;

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

[0053] Example 4

[0054] The preparation method of the high temperature resistant organic titanium fracturing fluid cross-linking agent of this embodiment 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, stir thoroughly, heat to 52° C., adjust the pH value to 6-7 with 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, raise the temperature to 65°C, and continue stirring the reaction for 2.4 h at a stirring speed of 450 rpm;

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

[0058] Example 5

[0059] The preparation method of the high temperature resistant organic titanium fracturing fluid cross-linking agent of this embodiment 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, stir thoroughly, heat to 58° C., adjust the pH value to 6-7 with 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, raise the temperature to 68°C, and continue stirring the reaction for 2.6 h at a stirring speed of 350 rpm;

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

[0063] Example 6

[0064] The preparation method of the high temperature resistant organic titanium fracturing fluid cross-linking agent of this embodiment 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, stir thoroughly, heat to 53° C., adjust the pH value to 6-7 with 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, raise the temperature to 66°C, and continue stirring for 2.8 h at a stirring speed of 400 rpm;

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

[0068] Example 7

[0069] The preparation method of the high temperature resistant organic titanium fracturing fluid cross-linking agent of this embodiment 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, stir thoroughly, heat to 55° C., adjust the pH value to 6-7 with 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, raise the temperature to 65°C, and continue stirring for 2.5 h at a stirring speed of 450 rpm;

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

[0073] Example 8

[0074] The preparation method of the high temperature resistant organic titanium fracturing fluid cross-linking agent of this embodiment 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, stir thoroughly, heat to 52° C., adjust the pH value to 6-7 with 2 mol / L NaOH solution, and react at constant temperature for 2 h;

[0076] (2) Add 130 g of diethanolamine and 45 g of p-aminopyridine, raise the temperature to 68°C, and continue stirring the reaction for 2.6 h at a stirring speed of 400 rpm;

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

[0078] 2. Experimental Example Application of High Temperature Resistant Organic Titanium Fracturing Fluid Crosslinking Agent

[0079] The cross-linking agent of each example and the polyacrylamide solution were mixed to prepare a fracturing fluid, and then the delayed cross-linking time, temperature resistance, and heat and shear resistance performance were evaluated.

[0080] 1. Delayed cross-linking experiment:

[0081] Dissolve 5g polyacrylamide in 1000ml water, take 400ml and pour it into the stirring cup of Wu Yin mixer, adjust the voltage to make the stirrer rotate until the bottom of the vortex can see the top of the stirrer. Take 2ml crosslinker solution and pour it into the stirring cup of the mixer with continuous stirring. Use a stopwatch to record the time from the time the crosslinker is poured until the vortex disappears and the liquid surface slightly protrudes, which is the crosslinking time. Use the commercially available organic aluminum crosslinker BHJ-106 for comparative experiments. The test results are shown in Table 1.

[0082] The cross-linked fracturing fluid is poured into a beaker and subjected to a hanging experiment. The fluid can be hung as a whole. Figure 1 The crosslinked fracturing fluid crosslinker G8 of the present invention is shown in the figure. Figure 1 It can be seen that after the fracturing fluid cross-linking agent of the present invention cross-links the polyacrylamide, the hanging performance is good.

[0083] 2. Evaluation of temperature resistance

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

[0085] 3. Evaluation of heat and shear resistance

[0086] Fracturing fluid crosslinkers G1 to G8 were prepared according to the delayed crosslinking experiment (the timing of adding the crosslinker was completed), added to the MARS-Ⅲ high temperature and high pressure rotational rheometer, and the heating rate was set to 3.0℃±0.2℃. After the sample was heated to 120℃, it was heated for 100s. -1 The shear rate was continuously sheared for 2 hours, and then the apparent viscosity value was read. A comparative experiment was performed with the commercially available crosslinking agent BHJ-106. The test results are shown in Table 1. Among them, the rheological curve of the fracturing fluid after G8 crosslinking is shown in Table 1. Figure 2 , where red is the temperature curve and blue is the apparent viscosity curve.

[0087] Table 1 Delayed crosslinking time, temperature resistance, heat resistance and shear resistance test results

[0088]

[0089]

[0090] It can be seen from Table 1 that the delay times of fracturing fluid cross-linking agents G1-G8 are 412s, 442s, 457s, 480s, 520s, 494s, 515s and 536s respectively, among which G8 has the longest delay time of 536s, and the delay times are all greater than 400s; while the delay time of BHJ-106 is 68s, which is significantly lower than the cross-linking agent of the present invention.

[0091] The temperature resistance of fracturing fluid crosslinking agents G1-G8 are 214°C, 220°C, 226°C, 229°C, 238°C, 228°C, 240°C, and 245°C, respectively, and the temperature resistance is greater than 210°C, among which the temperature resistance of G8 reaches the highest 245°C; while the temperature resistance of BHJ-106 is 137°C, and the temperature resistance is significantly lower than that of the present invention, indicating that the temperature resistance of the fracturing fluid crosslinking agent of the present invention is good.

[0092] The shear viscosity of fracturing fluid crosslinkers G1-G8 are 178mPa·s, 183mPa·s, 187mPa·s, 191mPa·s, 192mPa·s, 190mPa·s, 193mPa·s and 198mPa·s, respectively, all of which are greater than 170mPa·s. Among them, the shear viscosity of G8 is the largest, reaching 198mPa·s; while the shear viscosity of BHJ-106 is 68mPa·s, indicating that the shear resistance of the fracturing fluid crosslinker of the present invention is significantly stronger than that of BHJ-106.

[0093] Based on the above experiments, it can be seen that the organic titanium fracturing fluid cross-linking agent of the present invention has the following characteristics:

[0094] (1) The raw material sources of the fracturing fluid cross-linking agent of the present invention are wide, and the synthesis process is simple;

[0095] (2) The cross-linking agent for fracturing fluid of the present invention does not require separation during the reaction process, and the target product can be obtained by continuous reaction with a yield of 100%. All products can be used as cross-linking agents for fracturing fluid;

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

[0097] (4) After cross-linking, the fracturing fluid cross-linking agent of the present invention has heat resistance and shear resistance. After cross-linking, the temperature resistance of the fracturing fluid can reach above 210°C, and the shear resistance viscosity is greater than 170mPa·s, which can solve the problem of temperature resistance of fracturing fluid in high-temperature reservoir (210°C) fracturing construction. Therefore, it can be widely used in oil well or water well fracturing transformation of oil reservoirs.

Claims

1. A high temperature resistant organic titanium fracturing fluid crosslinking agent, characterized in that: The invention comprises a crosslinking agent body, wherein the crosslinking agent body takes Ti as the central atom, an organic group is bonded to the Ti central atom through a covalent bond and / or a coordination bond, and the organic group comprises a terminal hydroxyl organic carboxylic acid unit, an aminopyridine and a diethanolamine unit.

2. The high temperature resistant organic titanium fracturing fluid crosslinking agent according to claim 1, characterized in that: The organic group includes an amidation unit formed by amidation reaction of a terminal hydroxyl organic carboxylic acid and aminopyridine.

3. The high temperature resistant organic titanium fracturing fluid crosslinking agent according to claim 1, characterized in that: The organic titanium fracturing fluid cross-linking agent also includes a protective agent for delaying the cross-linking of the fracturing fluid, and the protective agent is a polyhydroxy compound.

4. The high temperature resistant organic titanium fracturing fluid crosslinking agent according to any one of claims 1 to 3, characterized in that The high temperature resistant organic titanium fracturing fluid cross-linking agent has a temperature resistance of above 210° C. when in use.

5. A method for preparing a high temperature resistant organic titanium fracturing fluid crosslinking agent, characterized in that: The following steps are involved: The titanium source, the terminal hydroxy organic carboxylic acid, diethanolamine and p-aminopyridine are reacted in water at 50-70°C.

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

6.

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

8. The method for preparing a high temperature resistant organic titanium fracturing fluid cross-linking agent according to claim 5, characterized in that: The reaction comprises first mixing a titanium source, water and a terminal hydroxy organic carboxylic acid to carry out a first reaction, and then adding diethanolamine and p-aminopyridine to carry out a second reaction; the first reaction is carried out under the condition of 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.

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

6.

10. Use of the high temperature resistant organic titanium fracturing fluid cross-linking agent according to any one of claims 1 to 4 in the fracturing reconstruction of oil wells or water wells in oil reservoirs.

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