An Energized Water-Based Fracturing Fluid, Its Preparation Method and Application

Abstract

This invention discloses an energy-enhancing water-based fracturing fluid, its preparation method, and its application, relating to the field of oilfield fracturing fluid technology. The preparation method includes: adding N,N-dimethylformamide as a solvent, then adding 2,3-epoxypropyl octadecenoic acid and acetic acid, followed by post-treatment to obtain solid intermediate monomer I; mixing sodium bisulfite with water and adding monomer I, along with an appropriate amount of catalyst, followed by treatment after the reaction to obtain intermediate monomer II; adding a zirconium salt solution of zirconium oxychloride dropwise to the monomer II solution and adjusting the pH to obtain a crosslinking agent. The crosslinking agent is then added to a guar gum thickener for crosslinking to obtain the fracturing fluid. The fracturing fluid uses viscosity-reducing molecules as ligands to synthesize an organozirconium crosslinking agent. During the crosslinking process, the original coordination bonds in the crosslinking agent break, releasing viscosity-reducing molecules, thereby enhancing the strength, solubility, and emulsifying and dispersing ability of the crosslinking agent. This imparts viscosity-reducing capabilities to the fracturing fluid, simplifying the process, shortening the time, and improving efficiency.

Description

Technical Field

[0001] This invention belongs to the field of oilfield fracturing fluid technology, specifically relating to an energy-enhancing water-based fracturing fluid, its preparation method, and its application. Background Technology

[0002] The density of crude oil in heavy oil reservoirs is generally 0.9174–0.9697 g / cm³. -3 The viscosity of crude oil in the formation ranges from 294 to 6160 mPa·s. Under surface conditions, the crude oil surface is non-flowable, and currently, viscosity reduction is achieved through dilution. However, dilution is suitable for use in the early stages of oilfield development when water cut is low. Once the water cut phase begins, it can easily lead to "diluted extraction," which is detrimental to improving well production. Furthermore, poor control of the dilution process can easily cause heavy oil backflow. Thermal or cold extraction can also be used, but thermal extraction suffers from high energy consumption, high cost, and low recovery rate. Chemical viscosity reduction, using surfactants instead of heating, has become a research hotspot for chemical cold extraction of heavy oil both domestically and internationally. However, during heavy oil extraction operations, fracturing must be performed first, followed by the injection of viscosity reducers, which significantly increases construction time, has low temperature resistance, and results in low extraction efficiency. Summary of the Invention

[0003] To address the shortcomings of existing fracturing operations, such as complexity and long construction time, and to enhance the temperature resistance of fracturing fluids, this invention aims to provide an energy-enhancing water-based fracturing fluid, its preparation method, and its application. During construction, fracturing fluid and viscosity reducer can be injected together in a single injection, with the crosslinking agent becoming the release source of the viscosity reducer. Simultaneous fracturing and viscosity reduction operations significantly shorten the construction cycle and increase the temperature resistance of the fracturing fluid.

[0004] To achieve the above objectives, the present invention employs the following technical solution:

[0005] This invention provides a method for preparing an energy-enabled water-based fracturing fluid, comprising the following steps:

[0006] S1: Take 2,3-epoxypropyl octadecenoic acid and acetic acid as solutes and dissolve them in N,N-dimethylformamide to form a solution. Perform a ring-opening reaction. After the reaction is completed, perform the first post-treatment to obtain intermediate monomer I.

[0007] S2: Prepare solution A by mixing sodium bisulfite with water, prepare solution B by mixing intermediate monomer I with ethanol, add solution B dropwise to solution A, then add catalyst to carry out addition reaction, and after the reaction is completed, perform a second post-treatment to obtain intermediate monomer II;

[0008] S3: The intermediate monomer II is used as a ligand to undergo a complexation reaction with zirconium oxychloride, and the pH value is adjusted to 7-8 to obtain an organozirconium crosslinking agent;

[0009] S4: Add guar gum thickener to the organozirconium crosslinking agent to crosslink it, and obtain an energy-enabled fracturing fluid.

[0010] In a further step of the present invention, the mass ratio of acetic acid to 2,3-epoxypropyl octadecenoic acid in S1 is (1-2):1, and the mass fraction of the solute is 32-34 wt%.

[0011] Furthermore, in the present invention, the temperature of the ring-opening reaction in S1 is 50-100°C, and the time of the ring-opening reaction is 0.5-3 hours;

[0012] The first post-treatment in S1 involves treating the ring-opening reaction product with an equal volume of distilled water to allow unreacted acetic acid and N,N-dimethylformamide to enter the aqueous phase. After cooling to room temperature, the product is washed with water and filtered to obtain powdered intermediate monomer I.

[0013] Furthermore, in the present invention, the molar ratio of sodium bisulfite to intermediate monomer I in S2 is (1-2):1;

[0014] The addition reaction in S2 is carried out at a temperature of 50–75°C for 0.3–2 hours.

[0015] The second post-treatment in S2 involves cooling the product to below 36°C after the addition reaction, followed by water washing and filtration to obtain powdered intermediate monomer II.

[0016] In a further step of the present invention, the catalyst in S2 is hydrogen peroxide, wherein the mass fraction of the hydrogen peroxide is 30 wt% and the amount added is 10-20 g.

[0017] In a further step of the present invention, the mass ratio of intermediate monomer II to zirconium oxychloride in step S3 is 1:(4-5); the pH value adjustment in step S3 uses sodium hydroxide, and the mass fraction of sodium hydroxide is 10%; the temperature of the complexation reaction in step S3 is 70-90°C, and the time of the complexation reaction is 3-5 hours.

[0018] In a further embodiment of the present invention, the mass fraction of the guar gum thickener in step S4 is 0.5–1 wt%; and the mass fraction of the organozirconium crosslinking agent is 0.4–0.8 wt%.

[0019] An energetic water-based fracturing fluid prepared by any one of the methods described above.

[0020] Furthermore, the organozirconium crosslinking agent in the fracturing fluid has the following molecular structure:

[0021]

[0022] The organozirconium crosslinking agent in the empowered water-based fracturing fluid simultaneously releases a viscosity reducer, the molecular structure of which is as follows:

[0023]

[0024] Application of an energy-enabled water-based fracturing fluid prepared by any one of the methods described above in heavy oil extraction operations.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] This invention provides a method for preparing an energy-enabled water-based fracturing fluid. A viscosity reducer is used as a ligand for an organozirconium crosslinking agent. First, it combines with zirconium ions to form an organozirconium crosslinking agent. Then, it is combined with a guar gum thickener to create a fracturing fluid, which is injected downhole. During fracturing operations, guar gum molecules complex with zirconium ions, thereby releasing the viscosity reducer molecules to reduce the viscosity of heavy oil. The zirconium metal ions in the synthesized crosslinking agent readily combine with the ortho-hydroxyl groups on the guar gum in the thickener to form a gel, causing the coordination bonds of the original crosslinking agent to break, thus releasing the viscosity reducer molecules to reduce the viscosity of heavy oil.

[0027] This invention provides an energy-enhancing water-based fracturing fluid. During use, a crosslinking agent and a thickener are mixed and injected downhole, where the fracturing fluid is formed by the downhole temperature. A zirconium metal ion complex crosslinking agent is synthesized using sulfonic acid polymer molecules as ligands. The zirconium ions in the crosslinking agent crosslink with the guar gum in the thickener, achieving fracturing while simultaneously releasing ligand compound molecules to reduce viscosity. A viscosity-reducing molecule is also provided, possessing a long carbon chain and hydrophilic groups. Upon release, it is both oleophilic at one end and hydrophilic at the other, reducing the oil-water interfacial tension and transforming the heavy oil in the formation from a water-in-oil state to an oil-in-water state. Furthermore, the oxygen and sulfonic acid groups in the molecule form a double electric layer on the surface of the crude oil droplets, creating electrostatic repulsion between the droplets, preventing them from approaching and adhering, thus reducing the viscosity of the heavy oil. This addresses the shortcomings of existing fracturing operations, such as complexity and long operation times, and provides viscosity reduction after fracturing operations are completed, while also enhancing the temperature resistance of the fracturing fluid.

[0028] This invention provides an energy-enhancing water-based fracturing fluid for heavy oil extraction operations. During construction, fracturing fluid and viscosity reducer can be injected together in a single injection. The crosslinking agent becomes the release source of the viscosity reducer, which can improve the strength, solubility, and emulsification and dispersion ability of the crosslinking agent, forming a slow-release crosslinked guar gum fracturing fluid system, thus empowering the fracturing fluid with viscosity reduction capabilities. Simultaneous fracturing and viscosity reduction operations greatly shorten the construction cycle. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the preparation process of intermediate monomer I;

[0030] Figure 2 This is a schematic diagram of the preparation process of intermediate monomer II;

[0031] Figure 3 This is a schematic diagram of the preparation process of the crosslinking agent;

[0032] Figure 4 This is a schematic diagram illustrating the working principle of fracturing fluid crosslinking.

[0033] Figure 5 This is a schematic diagram showing the viscosity of the energy-enhancing fracturing fluid in Example 3 as a function of temperature. Detailed Implementation

[0034] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0035] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0036] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0037] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0038] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0039] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0040] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0041] An energy-enhancing water-based fracturing fluid utilizes sulfonic acid polymer molecules as ligands to synthesize zirconium metal ion complex crosslinking agents. The zirconium ions in the crosslinking agent crosslink with guar gum in the thickener, achieving fracturing. Simultaneously, ligand compound molecules are released to reduce viscosity. Its viscosity-reducing molecular structure is as follows:

[0042]

[0043] The main structural formula of the crosslinking agent in the fracturing fluid is as follows:

[0044]

[0045] The specific preparation process of an energy-enhancing water-based fracturing fluid is achieved through the following reaction:

[0046]

[0047] Specifically, the present invention provides a method for preparing an energy-enabled water-based fracturing fluid, comprising the following steps:

[0048] 1) Add a certain amount of N,N-dimethylformamide as a solvent to a three-necked reaction flask equipped with a reflux condenser, and then add a certain amount of 2,3-epoxypropyl octadecenoic acid and acetic acid as solutes. React at a certain temperature for a certain time. The reaction is a ring-opening reaction. The mass ratio of acetic acid to 2,3-epoxypropyl octadecenoic acid is (1-2):1. The mass fraction of the solute is 32-34 wt%. The reaction temperature is 50-100℃. The reaction time is 0.5-3 h.

[0049] 2) Treat the reaction product with an equal volume of distilled water to allow unreacted acetic acid and solvent N,N-dimethylformamide to enter the aqueous phase. After cooling to room temperature, wash with water and filter. Repeat twice to obtain powdered solid intermediate monomer I.

[0050] 3) Take a certain amount of sodium bisulfite and water to prepare solution A, prepare monomer I and ethanol to prepare solution B, add solution B dropwise to the prepared solution A, add a small amount of hydrogen peroxide as a catalyst, and carry out the addition reaction at a certain temperature;

[0051] The molar ratio of monomer I to sodium bisulfite is 1:(1-2); the mass fraction of hydrogen peroxide is 30 wt%; the amount of hydrogen peroxide added is 10-20 g; the reaction temperature is 50-75℃; and the reaction time is 0.3-2 h.

[0052] 4) After the reaction is complete, cool to below 36°C, wash with water and filter, repeat twice to obtain powdered intermediate monomer II.

[0053] 5) Dissolve a certain amount of zirconium oxychloride in water, add it dropwise to monomer II solution, and adjust the pH to 7-8 with NaOH solution to carry out a complexation reaction to obtain organozirconium crosslinking agent;

[0054] The mass ratio of zirconium oxychloride to monomer II is 1:(4-5); the pH is adjusted to 7-8; the reaction temperature is 70-90℃; and the reaction time is 3-5h.

[0055] 6) Crosslinking the crosslinking agent with guar gum thickener yields the target product, an energy-enhancing water-based fracturing fluid.

[0056] The guar gum thickener has a mass fraction of 0.5–1 wt%, and the crosslinking agent has a mass fraction of 0.4–0.8 wt%.

[0057] Its working principle is mainly as follows: Sulfonic acid-based viscosity reducer molecules are used as ligands to synthesize organozirconium crosslinking agents. During the crosslinking process between zirconium ions in the crosslinking agent and guar gum thickener, fracturing is achieved. Simultaneously, the original coordination bonds in the crosslinking agent break, releasing viscosity reducer molecules. These molecules have long carbon chains and hydrophilic groups, allowing them to be oleophilic at one end and hydrophilic at the other. By reducing the interfacial tension between oil and water, they transform the heavy oil in the formation from a water-in-oil state to an oil-in-water state. Furthermore, the oxygen and sulfonic acid groups in the molecule can form an electric double layer on the surface of crude oil droplets, creating electrostatic repulsion between the droplets, hindering their approach and adhesion, thus reducing the viscosity of the heavy oil. The zirconium metal ions in the synthesized crosslinking agent readily combine with the ortho-hydroxyl groups on the guar gum in the thickener to form a gel, causing the original coordination bonds in the crosslinking agent to break, releasing viscosity reducer molecules for viscosity reduction. In other words, the ligands released after crosslinking by the synthesized crosslinking agent have a viscosity-reducing effect.

[0058] This invention synthesizes an organozirconium crosslinking agent by using sulfonic acid-based viscosity reducer molecules as ligands. During crosslinking with guar gum thickener, the original coordination bonds in the crosslinking agent break, releasing viscosity reducer molecules. This invention makes the crosslinking agent a source of viscosity reducer release, which can improve the crosslinking agent's strength, solubility, and emulsifying and dispersing ability, forming a slow-release crosslinked guar gum fracturing fluid system. This imparts viscosity-reducing ability to the fracturing fluid, greatly simplifying the operation process, shortening the operation time, and improving operation efficiency.

[0059] The energy-enhancing water-based fracturing fluid described in this invention can be applied in heavy oil extraction operations.

[0060] The present invention will be further described below with reference to specific embodiments and accompanying drawings:

[0061] Example 1

[0062] Preheat a thermostatically heated magnetically stirred oil bath. Add 75g of N,N-dimethylformamide as a solvent to a three-necked reaction flask equipped with a reflux condenser, followed by 12g of 2,3-epoxypropyl octadecenoic acid and 25g of acetic acid. React at 100℃ for 0.5h. Treat the reaction product with an equal volume of distilled water to allow unreacted acetic acid and the solvent N,N-dimethylformamide to enter the aqueous phase. After cooling to room temperature, wash twice with water and filter to obtain solid intermediate monomer I. Take 15g of sodium bisulfite and water... After mixing, 10g of monomer I and 10g of 30% hydrogen peroxide as a catalyst were added to a three-necked reaction flask equipped with a reflux condenser, and the mixture was reacted at 60℃ for 1 hour. After the reaction, the mixture was cooled to below 36℃, washed with water, and filtered twice to obtain powdered intermediate monomer II. A solution containing 1.5g of zirconium oxychloride was added dropwise to 20g of a 50% monomer II solution, and the pH was adjusted to 7 with NaOH. Distilled water was added to a volume of 100mL, and the mixture was reacted at 80℃ for 4 hours to obtain an organozirconium crosslinking agent. 0.6% of the crosslinking agent was added to a 0.6% guar gum thickener solution for crosslinking to obtain an energy-enabled water-based fracturing fluid.

[0063] Example 2

[0064] Preheat a thermostatically heated magnetically stirred oil bath. Add 62g of N,N-dimethylformamide as a solvent to a three-necked reaction flask equipped with a reflux condenser, followed by 12.6g of 2,3-epoxypropyl octadecenoic acid and 18g of acetic acid. React at 100℃ for 1 hour. Treat the reaction product with an equal volume of distilled water to allow unreacted acetic acid and the solvent N,N-dimethylformamide to enter the aqueous phase. After cooling to room temperature, wash twice with water and filter to obtain solid intermediate monomer I. Take 18g of sodium bisulfite and mix with water... 10g of monomer I and 10g of 30% hydrogen peroxide as a catalyst were added to a three-necked reaction flask equipped with a reflux condenser and reacted at 60℃ for 1 hour. After the reaction, the mixture was cooled to below 36℃, washed twice with water, and filtered to obtain powdered intermediate monomer II. A zirconium salt solution containing 1.5g of zirconium oxychloride was added dropwise to 20g of a 50% monomer II solution, and the pH was adjusted to 7 with NaOH. Distilled water was added to a volume of 100mL, and the mixture was reacted at 85℃ for 4.5 hours to obtain an organozirconium crosslinking agent. 0.6% of the crosslinking agent was added to a 0.6% guar gum thickener solution for crosslinking to obtain an energy-enabled water-based fracturing fluid.

[0065] Example 3

[0066] Preheat a thermostatically heated magnetically stirred oil bath. Add 71g of N,N-dimethylformamide as a solvent to a three-necked reaction flask equipped with a reflux condenser, followed by 15g of 2,3-epoxypropyl octadecenoic acid and 20g of acetic acid. React at 100℃ for 0.8h. Treat the reaction product with an equal volume of distilled water to allow unreacted acetic acid and the solvent N,N-dimethylformamide to enter the aqueous phase. After cooling to room temperature, wash with water and filter twice to obtain solid intermediate monomer I. Take 20g of sodium bisulfite and mix with water... After mixing, 12g of monomer I and 15g of 30% hydrogen peroxide as a catalyst were added to a three-necked reaction flask equipped with a reflux condenser and reacted at 60℃ for 1 hour. After the reaction, the mixture was cooled to 25℃, washed with water, and filtered twice to obtain powdered intermediate monomer II. A zirconium salt solution containing 1.5g of zirconium oxychloride was added dropwise to 20g of a 50% monomer II solution, and the pH was adjusted to 7 with NaOH. Distilled water was added to a volume of 100mL, and the mixture was reacted at 90℃ for 4 hours to obtain an organozirconium crosslinking agent. 0.8% of the crosslinking agent was added to a 1% guar gum thickener solution for crosslinking to obtain an energy-enabled water-based fracturing fluid.

[0067] Example 4

[0068] Preheat a thermostatically heated magnetically stirred oil bath. Add 112g of N,N-dimethylformamide as a solvent to a three-necked reaction flask equipped with a reflux condenser, followed by 20g of 2,3-epoxypropyl octadecenoic acid and 35g of acetic acid. React at 100℃ for 1 hour. Treat the reaction product with an equal volume of distilled water to allow unreacted acetic acid and the solvent N,N-dimethylformamide to enter the aqueous phase. After cooling to room temperature, wash twice with water and filter to obtain solid intermediate monomer I. Take 35g of sodium bisulfite and mix with water... After mixing, 10g of monomer I and 20g of 30% hydrogen peroxide as a catalyst were added to a three-necked reaction flask equipped with a reflux condenser and reacted at 55℃ for 1 hour. After the reaction, the mixture was cooled to 30℃, washed twice with water and filtered to obtain powdered intermediate monomer II. A zirconium salt solution containing 1.5g of zirconium oxychloride was added dropwise to 20g of a 50% monomer II solution, and the pH was adjusted to 7 with NaOH. Distilled water was added to a volume of 100mL, and the mixture was reacted at 80℃ for 4 hours to obtain an organozirconium crosslinking agent. 0.7% of the crosslinking agent was added to a 0.7% guar gum thickener solution for crosslinking to obtain an energy-enabled water-based fracturing fluid.

[0069] Example 5

[0070] Preheat a thermostatically heated magnetically stirred oil bath. Add 162g of N,N-dimethylformamide as a solvent to a three-necked reaction flask equipped with a reflux condenser, then add 30g of 2,3-epoxypropyl octadecenoic acid and 50g of acetic acid. React at 60°C for 2 hours. Treat the reaction product with an equal volume of distilled water to allow unreacted acetic acid and the solvent N,N-dimethylformamide to enter the aqueous phase. After cooling to room temperature, wash twice with water and filter to obtain solid intermediate monomer I. Take 60g of sodium bisulfite and mix with water, then add... 20g of monomer I was added, along with 15g of 30% hydrogen peroxide as a catalyst, into a three-necked reaction flask equipped with a reflux condenser. The mixture was reacted at 60℃ for 1.5h. After the reaction, the mixture was cooled to below 36℃, washed twice with water, and filtered to obtain powdered intermediate monomer II. A zirconium salt solution containing 1.5g of zirconium oxychloride was added dropwise to 20g of a 50% monomer II solution, and the pH was adjusted to 7 with NaOH. Distilled water was added to a volume of 100mL, and the mixture was reacted at 80℃ for 4h to obtain an organozirconium crosslinking agent. 0.6% of the crosslinking agent was added to a 1% guar gum thickener solution for crosslinking to obtain an energy-enabled water-based fracturing fluid.

[0071] Example 6

[0072] Preheat a thermostatically heated magnetically stirred oil bath. Add 162g of N,N-dimethylformamide as a solvent to a three-necked reaction flask equipped with a reflux condenser, followed by 30g of 2,3-epoxypropyl octadecenoic acid and 50g of acetic acid. React at 50°C for 3 hours. Treat the reaction product with an equal volume of distilled water to allow unreacted acetic acid and the solvent N,N-dimethylformamide to enter the aqueous phase. After cooling to room temperature, wash twice with water and filter to obtain solid intermediate monomer I. Take 60g of sodium bisulfite and mix with water, then add... 20g of monomer I and 15g of 30% hydrogen peroxide as a catalyst were added to a three-necked reaction flask equipped with a reflux condenser and reacted at 50℃ for 1.5h. After the reaction, the mixture was cooled to below 36℃, washed twice with water and filtered to obtain powdered intermediate monomer II. A zirconium salt solution containing 1.5g of zirconium oxychloride was added dropwise to 20g of a 50% monomer II solution, and the pH was adjusted to 8 with NaOH. Distilled water was added to a volume of 100mL, and the mixture was reacted at 70℃ for 3h to obtain an organozirconium crosslinking agent. 0.4% of the crosslinking agent was added to a 0.5% guar gum thickener solution for crosslinking to obtain an energy-enabled water-based fracturing fluid.

[0073] Example 7

[0074] Preheat a thermostatically heated magnetically stirred oil bath. Add 71g of N,N-dimethylformamide as a solvent to a three-necked reaction flask equipped with a reflux condenser, followed by 15g of 2,3-epoxypropyl octadecenoic acid and 20g of acetic acid. React at 50°C for 3 hours. Treat the reaction product with an equal volume of distilled water to allow unreacted acetic acid and the solvent N,N-dimethylformamide to enter the aqueous phase. After cooling to room temperature, wash twice with water and filter to obtain solid intermediate monomer I. Take 20g of sodium bisulfite and mix with water... 12g of monomer I and 15g of 30% hydrogen peroxide as a catalyst were added to a three-necked reaction flask equipped with a reflux condenser and reacted at 75℃ for 0.3h. After the reaction, the mixture was cooled to 25℃, washed twice with water, and filtered to obtain powdered intermediate monomer II. A zirconium salt solution containing 1.5g of zirconium oxychloride was added dropwise to 20g of a 50% monomer II solution, and the pH was adjusted to 8 with NaOH. Distilled water was added to a volume of 100mL, and the mixture was reacted at 90℃ for 5h to obtain an organozirconium crosslinking agent. 0.4% of the crosslinking agent was added to a 0.5% guar gum thickener solution for crosslinking to obtain an energy-enabled water-based fracturing fluid. Characterization and Testing:

[0075] The 1H NMR spectrum of the crosslinking agent of the empowered water-based fracturing fluid obtained in Example 3.

[0076] 1HNMR (300MHz, DMSO): δ6.29(t,2H), 4.42(d,4H), 2.80(t,1H), 2.32(t,4H), 1.66~1.65(m,12H), 1.25(s,44H), 0.88(m,6H)ppm.

[0077] The 1H NMR spectrum of an enhanced water-based fracturing fluid viscosity reducer obtained in Example 3

[0078] 1 HNMR (300MHz, DMSO): δ 6.29 (t, 1H), 5.22 (s, 2H), 4.42 (d, 2H), 2.80 (t, 1H), 2.32 (t, 2H), 1.66 ~ 1.65 (m, 6H), 1.26 ~ 1.25 (s, 22H), 0.88 (m, 3H) ppm.

[0079] To characterize the viscosity of the prepared fracturing fluid under temperature variations, the viscosity of an energy-enhancing fracturing fluid prepared in Example 3 was tested at a shear rate of 170 s⁻¹. -1 Temperature resistance performance was tested under the specified conditions. The results are as follows: Figure 5 The diagram shows the viscosity of the empowered fracturing fluid as a function of temperature. Figure 5 It can be seen that in the 170s -1 At a shear rate of 120°C, the viscosity of this activated fracturing fluid remains around 50 mPa·s, demonstrating its ability to withstand temperatures up to 120°C and its good temperature resistance.

[0080] Since this type of fracturing fluid also has a viscosity-reducing effect after fracturing operations, its viscosity-reducing ability was tested with crude oil (degassed) at 50℃ to characterize this effect, as shown in Table 1. Table 1 shows that the viscosity reduction rate can reach over 85% for crude oil from different oilfields, demonstrating excellent viscosity-reducing performance.

[0081] Table 1

[0082]

[0083]

[0084] The energy-enhancing water-based fracturing fluid described in this invention can be applied in heavy oil extraction operations. During operation, fracturing fluid and viscosity reducer can be injected together in a single injection, with the crosslinking agent acting as the release source for the viscosity reducer. Simultaneous fracturing and viscosity reduction operations significantly shorten the construction cycle, and the fluid exhibits good temperature resistance and excellent viscosity reduction performance.

[0085] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for preparing an energy-enhancing water-based fracturing fluid, characterized in that, Includes the following steps: S1: Take 2,3-epoxypropyl octadecenoic acid and acetic acid as solutes and dissolve them in N,N-dimethylformamide to form a solution. Perform a ring-opening reaction. After the reaction is completed, perform the first post-treatment to obtain intermediate monomer I. S2: Prepare solution A by mixing sodium bisulfite with water, prepare solution B by mixing intermediate monomer I with ethanol, add solution B dropwise to solution A, then add catalyst to carry out addition reaction, and after the reaction is completed, perform a second post-treatment to obtain intermediate monomer II; S3: The intermediate monomer II is used as a ligand to undergo a complexation reaction with zirconium oxychloride, and the pH value is adjusted to 7-8 to obtain an organozirconium crosslinking agent; S4: Add guar gum thickener to organozirconium crosslinking agent to crosslink, and obtain an energy-enabled fracturing fluid; The molar ratio of sodium bisulfite to intermediate monomer I in S2 is (1~2):1; The addition reaction in S2 is carried out at a temperature of 50~75℃ for 0.3~2h. The catalyst in S2 is hydrogen peroxide, and the mass fraction of the hydrogen peroxide is 30 wt%.

2. The method for preparing an energy-enabled water-based fracturing fluid according to claim 1, characterized in that, The mass ratio of acetic acid to 2,3-epoxypropyl octadecenoic acid in S1 is (1~2):1, and the mass fraction of the solute is 32~34wt%.

3. The method for preparing an energy-enabled water-based fracturing fluid according to claim 1, characterized in that, The ring-opening reaction in S1 is carried out at a temperature of 50~100℃ for 0.5~3h. The first post-treatment in S1 involves treating the ring-opening reaction product with an equal volume of distilled water to allow unreacted acetic acid and N,N-dimethylformamide to enter the aqueous phase. After cooling to room temperature, the product is washed with water and filtered to obtain powdered intermediate monomer I.

4. The method for preparing an energy-enabled water-based fracturing fluid according to claim 1, characterized in that, The second post-treatment in S2 involves cooling the product to below 36°C after the addition reaction, followed by water washing and filtration to obtain powdered intermediate monomer II.

5. The method for preparing an energy-enabled water-based fracturing fluid according to claim 1, characterized in that, The amount of hydrogen peroxide added is 10~20g.

6. The method for preparing an energy-enabled water-based fracturing fluid according to claim 1, characterized in that, The mass ratio of intermediate monomer II to zirconium oxychloride in S3 is 1:(4~5); the pH value adjustment in S3 uses sodium hydroxide, and the mass fraction of sodium hydroxide is 10%; the temperature of the complexation reaction in S3 is 70~90℃, and the time of the complexation reaction is 3~5h.

7. The method for preparing an energy-enabled water-based fracturing fluid according to claim 1, characterized in that, The mass fraction of the guar gum thickener in S4 is 0.5~1wt%; the mass fraction of the organozirconium crosslinking agent is 0.4~0.8wt%.

8. An energy-enabled water-based fracturing fluid prepared by any one of claims 1 to 7.

9. The energy-enhancing water-based fracturing fluid according to claim 8, characterized in that, The molecular structure of the organozirconium crosslinking agent in the fracturing fluid is as follows: The organozirconium crosslinking agent in the empowered water-based fracturing fluid simultaneously releases a viscosity reducer, the molecular structure of which is as follows: 。 10. The application of an energy-enabled water-based fracturing fluid prepared by any one of claims 1 to 7 in heavy oil extraction operations.

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