An organic zirconium cross-linking agent and its preparation method and application

Abstract

The present invention belongs to the field of oil production technology, and specifically relates to an organic zirconium cross-linking agent and its preparation method and application. The preparation method is as follows: zirconium tetrachloride and triethylene glycol are added to a reactor, stirred for reaction for 30-60 minutes, heated to 60-65°C, and kept warm for reaction for 30-60 minutes; 4-aminopyridine is added to the above reactor, heated to 65-70°C, and kept warm for reaction for 60-120 minutes; cooled to below 40°C, ethanol is added, and pH is adjusted to 7-8 with ammonia water to obtain a product organic zirconium cross-linking agent. The cross-linking agent of the present invention has the advantages of controllable cross-linking time, good cross-linking effect and strong antibacterial ability.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum extraction, and specifically relates to an organic zirconium cross-linking agent and a preparation method and application thereof. Background Art

[0002] As an important means of increasing production, fracturing technology is widely used in the transformation of low-permeability and ultra-low-permeability oil and gas reservoirs. In the fracturing process, fracturing fluid is a key material, and its performance directly affects the fracturing effect and oil and gas production. As an important component of fracturing fluid, cross-linking agent has an important influence on the rheological properties, temperature resistance and gel breaking properties of fracturing fluid. It forms a high-viscosity gel through cross-linking thickener to achieve the purpose of seam formation and sand carrying. The performance of fracturing fluid is a key factor in the effect of fracturing operations. A good fracturing fluid should have the following advantages: it can control the cross-linking speed, achieve delayed cross-linking, improve temperature resistance, and meet the requirements of operations at different formation temperatures.

[0003] CN106800927A discloses a guar fracturing fluid crosslinker, comprising a first component and a second component, wherein the first component comprises a polyhydroxy compound, boric acid and an organic amine, and the second component comprises an inorganic base, a metal ion complexing agent and water; the weight ratio of the first component to the second component is 1:4-5:2. The invention provides a method for preparing the crosslinker, comprising: preparing the first component: adding the polyhydroxy compound to the first reactor at room temperature, adding boric acid under stirring, heating to 43-53°C, keeping the temperature constant for 25-35 minutes, adding an organic amine to the first reactor, controlling the reaction temperature to 55-65°C, keeping the temperature constant for 25-35 minutes, and cooling to room temperature to obtain the first component; preparing the second component: adding water to the second reactor, adding the metal ion complexing agent under stirring until it is completely dissolved, adding the inorganic base to the second reactor in batches, controlling the reaction temperature to be lower than 70°C, stirring the reaction until the solution is clear, and cooling to room temperature to obtain the second component. The invention also provides a guar fracturing fluid using the crosslinker. However, the cross-linking agent of the invention can only act on plant gums, especially hydroxypropyl guar gum, and cannot achieve effective cross-linking on polyacrylamide, which limits its scope of application.

[0004] CN104560003A discloses an organic boron zirconium crosslinking agent, which belongs to the technical field of oilfield fracturing fluid. In order to solve the problems that the existing organic boron zirconium crosslinking agent is prepared with expensive organic zirconium complex as raw material, the raw material cost of the organic boron zirconium crosslinking agent is high, and its economic benefits are reduced, the invention provides an organic boron zirconium crosslinking agent, and its formula is: 1 part of inorganic zirconium salt; 2-4 parts of water; 3-6 parts of isopropanol; 0.4-1 part of inorganic boron compound; 4-20 parts of methanol; 2-4 parts of polyol; 1-2 parts of sodium α-hydroxycarboxylate; 1-2 parts of triethanolamine; 0.5-1 part of tetrahydroxypropyl ethylenediamine. The organic boron zirconium crosslinking agent provided by the invention uses cheap inorganic zirconium salt as raw material, which greatly saves costs and is conducive to the marketization of organic boron zirconium crosslinking agents and their wide application in high temperature resistant fracturing fluid systems. According to the viscosity-temperature curve provided, the viscosity of the crosslinking agent fracturing fluid of the invention is less than 100mPa•s after 80 minutes of shearing, and the shear resistance needs to be further improved. Summary of the invention

[0005] The present invention aims to provide an organic zirconium crosslinking agent and its preparation method and application in view of the above-mentioned deficiencies in the prior art. The crosslinking agent of the present invention has the advantages of controllable crosslinking time, good crosslinking effect and strong antibacterial ability.

[0006] One of the purposes of the present invention is to disclose an organic zirconium crosslinking agent, the molecular structure of the organic zirconium crosslinking agent is:

[0007] , and One or more of the .

[0008] Another object of the present invention is to disclose a method for preparing an organic zirconium crosslinking agent, wherein the specific steps of the preparation method are as follows:

[0009] (1) Add zirconium tetrachloride and triethylene glycol into the reactor, stir and react for 30-60 minutes, heat to 60-65°C, and continue to keep the temperature and react for 30-60 minutes;

[0010] (2) Add 4-aminopyridine to the above reactor, heat to 65-70°C, and continue to react at this temperature for 60-120 minutes;

[0011] (3) Cooling to below 40°C, adding ethanol, and adjusting the pH to 7-8 with aqueous ammonia to obtain the product organic zirconium cross-linking agent.

[0012] In the present invention, preferably, based on 1 mol part of zirconium tetrachloride, the triethylene glycol and 4-aminopyridine are 1.6-4.4 mol parts and 1.6-2.4 mol parts, respectively.

[0013] In the present invention, preferably, based on 1 part by mass of zirconium tetrachloride, the ethanol is 2-2.5 parts by mass.

[0014] The synthesis reaction equation of the organic zirconium crosslinking agent of the present invention is as follows:

[0015]

[0016]

[0017] or

[0018] or

[0019] or

[0020] or

[0021] The third object of the present invention is to disclose the application of the above organic zirconium cross-linking agent in oil field fracturing.

[0022] The organic zirconium crosslinking agent of the present invention is a delayed organic zirconium crosslinking agent, which can realize crosslinking of guar gum and polyacrylamide. The present invention contains a large number of hydroxyl groups, which can form covalent bonds with zirconium atoms and undergo multinuclear hydroxyl bridge complexation. The present invention contains a large number of amino groups, which can undergo coordination reactions with zirconium atoms, making it difficult for zirconium atoms to be released from molecules, so the present invention has a delayed crosslinking effect. Aminopyridine has a bactericidal effect, so the present invention has an antibacterial effect.

[0023] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0024] (1) The crosslinking time range of the organic zirconium crosslinking agent of the present invention is wide and can be controlled between 70-510s;

[0025] (2) The viscosity of the fracturing fluid after the cross-linking agent of the present invention is relatively high, and the viscosity at 70°C can reach 810 mPa•s;

[0026] (3) The fracturing fluid treated with the cross-linking agent of the present invention has a strong antibacterial effect, and the viscosity retention rate can reach up to 98.1% after being placed at 30°C for 48 hours. DETAILED DESCRIPTION

[0027] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0028] The present invention will be further described below in conjunction with specific embodiments:

[0029] Example 1

[0030] (1) Add 0.1 mol zirconium tetrachloride and 0.16 mol triethylene glycol into the reactor, stir and react for 30 min, heat to 60°C, and continue to keep the temperature for 30 min;

[0031] (2) Add 0.24 mol of 4-aminopyridine to the above reactor, heat to 65°C, and continue to react at this temperature for 60 minutes;

[0032] (3) Cool down to below 40°C, add 47 g of ethanol, and adjust the pH to 7-8 with aqueous ammonia to obtain the product organic zirconium cross-linking agent.

[0033] Example 2

[0034] (1) Add 0.1 mol zirconium tetrachloride and 0.2 mol triethylene glycol into the reactor, stir and react for 60 min, heat to 65 °C, and continue to keep the temperature for 30 min;

[0035] (2) Add 0.23 mol of 4-aminopyridine to the above reactor, heat to 70°C, and continue to react at this temperature for 120 min;

[0036] (3) Cool down to below 40°C, add 48g of ethanol, and adjust the pH to 7-8 with aqueous ammonia to obtain the product organic zirconium cross-linking agent.

[0037] Example 3

[0038] (1) Add 0.1 mol zirconium tetrachloride and 0.24 mol triethylene glycol into the reactor, stir and react for 35 minutes, heat to 65°C, and continue to keep the temperature for 50 minutes;

[0039] (2) Add 0.22 mol of 4-aminopyridine to the above reactor, heat to 70°C, and continue to react at this temperature for 60 minutes;

[0040] (3) Cool down to below 40°C, add 50g of ethanol, and adjust the pH to 7-8 with aqueous ammonia to obtain the product organic zirconium cross-linking agent.

[0041] Example 4

[0042] (1) Add 0.1 mol zirconium tetrachloride and 0.28 mol triethylene glycol into the reactor, stir and react for 50 min, heat to 65°C, and continue to keep the temperature for 35 min;

[0043] (2) Add 0.21 mol of 4-aminopyridine to the above reactor, heat to 65°C, and continue to react at this temperature for 120 minutes;

[0044] (3) Cool down to below 40°C, add 52 g of ethanol, and adjust the pH to 7-8 with aqueous ammonia to obtain the product organic zirconium cross-linking agent.

[0045] Example 5

[0046] (1) Add 0.1 mol zirconium tetrachloride and 0.32 mol triethylene glycol into the reactor, stir and react for 45 minutes, heat to 62°C, and continue to keep the temperature for 45 minutes;

[0047] (2) Add 0.2 mol of 4-aminopyridine to the above reactor, heat to 69°C, and continue to react at this temperature for 80 minutes;

[0048] (3) Cool down to below 40°C, add 54 g of ethanol, and adjust the pH to 7-8 with aqueous ammonia to obtain the product organic zirconium cross-linking agent.

[0049] Example 6

[0050] (1) Add 0.1 mol zirconium tetrachloride and 0.36 mol triethylene glycol into the reactor, stir and react for 50 min, heat to 65°C, and continue to keep the temperature for 60 min;

[0051] (2) Add 0.19 mol of 4-aminopyridine to the above reactor, heat to 66°C, and continue to react at this temperature for 120 min;

[0052] (3) Cool down to below 40°C, add 56 g of ethanol, and adjust the pH to 7-8 with aqueous ammonia to obtain the product organic zirconium cross-linking agent.

[0053] Example 7

[0054] (1) Add 0.1 mol zirconium tetrachloride and 0.4 mol triethylene glycol into the reactor, stir and react for 60 min, heat to 62 °C, and continue to keep the temperature for 38 min;

[0055] (2) Add 0.18 mol of 4-aminopyridine to the above reactor, heat to 70°C, and continue to react at this temperature for 60 minutes;

[0056] (3) Cool down to below 40°C, add 57 g of ethanol, and adjust the pH to 7-8 with aqueous ammonia to obtain the product organic zirconium cross-linking agent.

[0057] Example 8

[0058] (1) Add 0.1 mol zirconium tetrachloride and 0.44 mol triethylene glycol into the reactor, stir and react for 50 min, heat to 65°C, and continue to keep the temperature for 60 min;

[0059] (2) Add 0.16 mol of 4-aminopyridine to the above reactor, heat to 67°C, and continue to react at this temperature for 100 min;

[0060] (3) Cool down to below 40°C, add 58g of ethanol, and adjust the pH to 7-8 with aqueous ammonia to obtain the product organic zirconium cross-linking agent.

[0061] Example 9 Cross-linking time and viscosity test of cross-linked fracturing fluid

[0062] 500 mL of water was measured and poured into a sterile mixer, and the mixer was stirred at a speed of 3000 rpm. 3.0 g of commercially available hydroxypropyl guar gum was added, and stirred evenly. The mixture was placed in a water bath at 30° C. for 4 h to obtain a fracturing fluid thickener.

[0063] Preparation of gel: 70 ml of the above thickener was measured and poured into a 100 ml beaker. 0.35 ml of the organic zirconium crosslinking agent of the present invention (Example 1-8) was added under stirring with a glass rod. The timing was started until a fracturing gel that could be hung was formed. The timing ended at the crosslinking time t. The test results are shown in Table 1.

[0064] A comparative experiment was conducted using the organic boron zirconium crosslinker from Sichuan Enerjie Technology Co., Ltd.

[0065] It can be seen from Table 1 that the organic zirconium crosslinking agent of the present invention (Examples 1-8) has a wide crosslinking time range, which can be controlled between 70-510 s; while the crosslinking time of the comparative experiment is 60 s, and the crosslinking time is uncontrollable.

[0066] Example 10 Fracturing fluid viscosity test

[0067] The fracturing fluid in Example 9 was heated to 70°C and viscometer was used at a shear rate of 170 s -1 The viscosity μ0 was tested under the conditions of , and the test results are shown in Table 1.

[0068] A comparative experiment was conducted using the organic boron zirconium crosslinker from Sichuan Enerjie Technology Co., Ltd.

[0069] It can be seen from Table 1 that the viscosity of the fracturing fluid after the organic zirconium crosslinking agent of the present invention (Examples 1-8) is relatively high, and the viscosity at 70°C is above 600 mPa•s, and the highest is 810 mPa•s (Example 1); while the viscosity of the comparative experiment is 450 mPa•s, which is significantly lower than that of the present invention.

[0070] Example 11 Antibacterial ability test after cross-linking

[0071] The fracturing fluid sample in Example 10 was placed in an environment of 30°C for 48 hours, and the fracturing fluid was heated to 70°C and measured using a Fann-35 rotational viscometer at a shear rate of 170 s -1 The viscosity μ1 was tested under the conditions and the viscosity retention rate was calculated.

[0072] η=μ1 / μ0× 100%

[0073] The experimental results are shown in Table 1.

[0074] A comparative experiment was conducted using the organic boron zirconium crosslinker from Sichuan Enerjie Technology Co., Ltd.

[0075] Table 1 Cross-linking time, viscosity, and antibacterial ability test results

[0076]

[0077] It can be seen from Table 1 that the fracturing fluid treated with the organic zirconium crosslinking agent of the present invention (Examples 1-8) has a strong antibacterial effect, and the viscosity retention rate after being placed at 30°C for 48 hours is greater than 91%, and can reach a maximum of 98.1% (Example 1); while the viscosity retention rate of the comparative experiment is 31.1%, which is significantly lower than that of the present invention.

[0078] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0079] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0080] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for preparing an organic zirconium crosslinking agent, characterized in that: The specific steps of the preparation method are as follows: (1) Add zirconium tetrachloride and triethylene glycol into the reactor, stir and react for 30-60 minutes, heat to 60-65°C, and continue to keep the temperature and react for 30-60 minutes; (2) Add 4-aminopyridine to the above reactor, heat to 65-70°C, and continue to react at this temperature for 60-120 minutes; (3) Cooling to below 40°C, adding ethanol, and adjusting the pH to 7-8 with aqueous ammonia to obtain the product organic zirconium cross-linking agent; Based on 1 mol part of zirconium tetrachloride, the triethylene glycol and 4-aminopyridine are 1.6-4.4 mol parts and 1.6-2.4 mol parts respectively.

2. The preparation method according to claim 1, characterized in that: Based on 1 part by mass of zirconium tetrachloride, the ethanol is 2-2.5 parts by mass.

3. An organic zirconium crosslinking agent, characterized in that The molecular structure of the organic zirconium crosslinking agent is: , and One or more of the .

4. Use of the organic zirconium cross-linking agent according to claim 3 in oil field fracturing.

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