Amphiphilic nano MOF composite carrier as well as preparation method and application thereof

Abstract

The invention relates to the technical field of oil-gas field development, in particular to an amphiphilic nano MOF composite carrier and a preparation method and application thereof. The amphiphilic nano MOF composite carrier is Fe / Zr heterostructure MOF obtained by a solvothermal method, and the pore size is regulated and controlled by a template agent to obtain the Fe / Zr heterostructure MOF with different pore sizes; the preparation method comprises the following steps: grafting a carboxylic acid group to a Fe / Zr heterostructure MOF through an oxidation method, carrying out a silane coupling reaction to obtain a surface-aminated MOF, and grafting an alkyl group to the surface-aminated MOF to obtain a surface-modified MOF; nano zero-valent iron is loaded on the surface modified MOF through a reduction method, lipase is immobilized on the surface modified MOF through a covalent anchoring method, and the amphiphilic nano MOF composite carrier is obtained. The cleaning efficiency of the amphiphilic nano MOF composite carrier on composite blockage is improved by 2-3 times, and the environmental toxicity is reduced by 60% or above.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas field development technology, specifically relating to an amphiphilic nano-MOF composite carrier, its preparation method, and its application. Background Technology

[0002] During oil, gas, and water wells can become clogged in the wellbore and formation pores due to various reasons, preventing the smooth flow of oil and gas and thus reducing production. There are three main causes of this clogging: First, during profile control and displacement adjustments, injected polymers and gels are adsorbed and retained in the pores, becoming entangled with other blockages and accumulating in the oil layer, leading to blockage. Second, in some oilfield blocks, conventional oil and water wells accumulate various inorganic scales such as carbonates, silicates, and sulfates during long-term production, causing formation blockage and contaminating the reservoir. Third, as production time increases, formation pressure decreases, leading to the accumulation of large amounts of polluted oil, heavy components of crude oil, and asphaltene near the wellbore, causing blockage in the near-wellbore area; some medium- to high-permeability reservoirs may also experience blockage. Unblocking can remove these blockages, restore formation permeability, allow oil and gas to flow more smoothly, and increase production.

[0003] Currently, commonly used unblocking agents include chemical, physical, and biological unblocking agents. Chemical unblocking primarily uses acids, strong oxidants, and surfactants; however, these agents are prone to corroding pipelines, have short shelf lives, and pose safety concerns. Physical unblocking mainly uses pulse or vibration methods, but this method suffers from complex application processes and limited application range. Biological unblocking primarily utilizes enzymes, leveraging microbial metabolism to degrade long polymer chains; however, this method has limitations due to high enzyme requirements and inconsistent unblocking effects. It can be seen that existing unblocking agents typically employ a single unblocking method; however, the causes of oil reservoir blockage are complex, and existing unblocking agents are not ideal for clearing complex blockages. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides an amphiphilic nano-MOF composite carrier, its preparation method, and its applications. Through precise molecular engineering, a multi-scale reaction interface is constructed, achieving synergistic effects of three deblocking mechanisms. Compared to traditional single-mechanism deblocking agents, this method improves the removal efficiency of complex blockages by 2-3 times and reduces environmental toxicity by more than 60%.

[0005] The specific technical solution of the present invention is as follows.

[0006] The first aspect of this invention provides an amphiphilic nano-MOF composite support, wherein the amphiphilic nano-MOF composite support is obtained by solvothermal method to obtain Fe / Zr heterostructure MOF, and the pore size is controlled by template agent to obtain Fe / Zr heterostructure MOF with different pore sizes; the diameter of the different pores is 2nm~3nm, 5nm~7nm and 8nm~10nm; After oxidation, carboxylic acid groups are grafted onto the Fe / Zr heterostructure MOF, and then a surface-aminated MOF is obtained through silane coupling reaction. After grafting alkyl groups onto it, a surface-modified MOF is obtained. Nano-zero valent iron was loaded onto a surface-modified MOF using a reduction method, and lipase was immobilized on the surface-modified MOF using a covalent anchoring method to obtain the amphiphilic nano-MOF composite carrier.

[0007] This invention constructs an amphiphilic nano-MOF composite carrier with precise pore-function matching characteristics. A three-level gradient pore structure is constructed through a multi-template agent strategy, and on this basis, the spatially oriented integration of multifunctional components is realized.

[0008] Macropores with a diameter of 8nm~10nm serve as adsorption and diffusion channels for heavy oil and asphaltenes, mesopores with a diameter of 5nm~7nm act as confined oxidation reactors for polymer scale, and micropores with a diameter of 2nm~3nm serve as active sites for lipase immobilization and chelation reactions. These three synergistically form a tandem deblocking pathway of physical adsorption—chemical oxidation—biocatalysis / complexation. The carrier surface is modified by carboxylation and amination to give it amphiphilicity, which not only enhances interfacial adaptability but also provides active sites for the stable loading of the catalytic oxidant nano-zero-valent iron and the biocatalyst lipase. Ultimately, this achieves efficient, synergistic, and deep removal of complex reservoir blockages, namely organic polymers, heavy oil micelles, and inorganic scale.

[0009] In another preferred embodiment, the template agent is hexadecyltrimethylammonium bromide, Pluronic F127 block copolymer, and polystyrene microspheres; the mass of hexadecyltrimethylammonium bromide is 0.01%~0.05% of the mass of the Fe / Zr heterostructure MOF, the mass of Pluronic F127 block copolymer is 0.05%~0.1% of the mass of the Fe / Zr heterostructure MOF, and the concentration of polystyrene microspheres in the Fe / Zr heterostructure MOF is 0.5 mg / mL~2.5 mg / mL; The hexadecyltrimethylammonium bromide is used to form channels with a diameter of 2 nm to 3 nm; The Pluronic F127 block copolymer is used to form channels with a diameter of 5 nm to 7 nm; The polystyrene microspheres are used to form channels with a diameter of 8 nm to 10 nm.

[0010] A second aspect of this invention provides a method for preparing the aforementioned amphiphilic nano-MOF composite support, comprising the following steps: Iron ion precursor solution, zirconium ion precursor solution and ligands were mixed and subjected to a solvothermal reaction to obtain Fe / Zr heterostructure MOF; wherein the ligands were pyromellitic acid and 2-aminoterephthalic acid. By sequentially adding the template agent hexadecyltrimethylammonium bromide, Pluronic F127 block copolymer, and polystyrene microspheres to Fe / Zr heterostructure MOFs, Fe / Zr heterostructure MOFs with different pore sizes were obtained. Fe / Zr heterostructure MOFs with different pore sizes were immersed in acid and subjected to oxidation to achieve a carboxylic acid group concentration of 0.8 mmol / g to 1.3 mmol / g on the grafted Fe / Zr heterostructure MOFs. The MOFs were then dispersed in an organic solvent, a silane coupling agent was added, and the mixture was refluxed at 105℃ to 110℃ for 4 to 8 hours to obtain surface-aminated MOFs. The surface-aminated MOFs were then reacted with stearoyl chloride to graft alkyl groups onto the surface-aminated MOFs, resulting in surface-modified MOFs. The suspension of surface-modified MOF was mixed with FeSO4 solution, and NaBH4 was added to carry out a reduction deposition reaction, so that nano-zero valent iron was loaded on the surface-modified MOF. The amino groups on the surface of the surface-modified MOF were activated with glutaraldehyde, and then lipase was added to carry out an immobilization reaction to obtain the amphiphilic nano-MOF composite carrier.

[0011] In another preferred embodiment, the molar ratio of the iron ion precursor solution, the zirconium ion precursor solution, and the ligand is 0.05M~0.15M : 0.03M~0.08M : 1.0M~1.8M; The molar ratio of pyromellitic acid to 2-aminoterephthalic acid is 1.0M~1.5M:0.2M~0.4M.

[0012] In another preferred embodiment, the conditions for the solvothermal reaction are as follows: temperature 100℃~130℃, time 8h~16h; After the solvothermal reaction, centrifugation and alternating washing with ethanol and N,N-dimethylformamide yielded the Fe / Zr heterostructure MOF.

[0013] In another preferred embodiment, the polystyrene microspheres have a particle size of 0.2 μm to 0.5 μm.

[0014] In another preferred embodiment, the acid solution is obtained by mixing hydrogen peroxide and nitric acid in a volume ratio of 3:1; the organic solvent is toluene, and the silane coupling agent is 3-aminopropyltriethoxysilane.

[0015] In another preferred embodiment, the molar ratio of the surface-modified MOF suspension, FeSO4 solution, and NaBH4 is 1:0.4~0.7:0.8~1.2; The mass percentage of glutaraldehyde is 2.5%, the concentration of lipase is 5 mg / mL to 15 mg / mL, the concentration of the surface-modified MOF suspension is 5 mg / mL to 20 mg / mL, and the volume ratio of glutaraldehyde, surface-modified MOF suspension, and lipase is 1:2:1 to 3.

[0016] The third aspect of this invention provides the application of the aforementioned amphiphilic nano-MOF composite carrier in unclogging oil, gas and water wells.

[0017] In another preferred embodiment, the unblocking of oil, gas and water wells includes unblocking heavy oil / asphalt, unblocking organic scale, and unblocking inorganic scale.

[0018] Compared with the prior art, the present invention has the following beneficial effects.

[0019] This invention employs a three-tiered pore design: macropores (8nm-10nm in diameter) adsorb and diffuse heavy oil and asphaltenes, allowing the long-chain alkyl structures on the surface of the amphiphilic nano-MOF composite carrier to hydrophobically interact with the oil phase, promoting the stripping and dispersion of oily blockages; mesopores (5nm-7nm in diameter) adsorb polymeric organic fouling, enabling confined oxidative degradation of polymeric organic scale; and micropores (2nm-3nm in diameter) provide a high specific surface area and dense anchoring sites, allowing for the grafting of more carboxyl and amino functional groups. Carboxyl and amino functional groups are the main sites for lipase immobilization and chelation reactions, enabling enzymatic decomposition of organic residues and the multi-toothed complexing and dissolving effect of ethylenediaminetetramethylenephosphonic acid on inorganic scale. This invention utilizes precise molecular engineering to construct multi-scale reaction interfaces, achieving spatiotemporal synergy of three unblocking mechanisms. Compared to traditional single-mechanism unblocking agents, it improves the removal efficiency of complex blockages by 2-3 times and reduces environmental toxicity by more than 60%. Attached Figure Description

[0020] Figure 1 The diagram shows the aperture distribution in Examples 1 to 3, where 1 represents Example 1, 2 represents Example 2, and 3 represents Example 3.

[0021] Figure 2 The image shows the results of a heavy oil intrusion experiment using CT scanning of an amphiphilic nano-MOF composite carrier solution.

[0022] Figure 3The figure shows the apparent viscosity of core produced fluid with different concentrations of amphiphilic nano-MOF composite carrier solutions. 1 represents an amphiphilic nano-MOF composite carrier solution with a mass percentage concentration of 0.1%, 2 represents an amphiphilic nano-MOF composite carrier solution with a mass percentage concentration of 0.3%, and 3 represents an amphiphilic nano-MOF composite carrier solution with a mass percentage concentration of 0.5%.

[0023] Figure 4 Figures showing the dissolution rates of calcium carbonate samples by amphiphilic nano-MOF composite carrier solutions in different embodiments, where 1 represents Example 1, 2 represents Example 2, and 3 represents Example 3.

[0024] Figure 5 This is a comparison image showing the effects of calcium carbonate sample dissolution before and after.

[0025] Figure 6 Results of the dissolution rate of quartz framework by amphiphilic nano-MOF composite support and argillaceous acid corrosion inhibitor. Figure 1 1 indicates a 10% mass percentage concentration of argon acid corrosion inhibitor, and 2 indicates a 10% mass percentage concentration of an aqueous solution of amphiphilic nano-MOF composite carrier. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0027] Unless otherwise specified, the experimental methods described in the following embodiments are conventional methods; unless otherwise specified, the reagents and materials are commercially available.

[0028] Cetyltrimethylammonium bromide was purchased from Shanghai Maclean Biotechnology Co., Ltd., with a purity of 99%, and is referred to as CTAB in the following examples; Pluronic F127 block copolymer was purchased from Energia, with Mn of 12000, wherein Pluronic F127 is a triblock nonionic polyether surfactant, PEO-PPO-PEO block copolymer; polystyrene microspheres were purchased from Yuanye Biotechnology, with a particle size of 0.2μm~0.5μm, 2.5% w / v, and are referred to as PS microspheres in the following examples; lipase was purchased from Shanghai Maclean Biotechnology Co., Ltd., with a purity of 20000U / g.

[0029] Example 1: A method for preparing an amphiphilic nano-MOF composite carrier, comprising the following steps.

[0030] S1. Synthesis of heterostructured Fe / Zr-MOF: A solvent system was prepared using N,N-dimethylformamide, ethanol, and water in a ratio of 8:1:1. 0.1M FeCl3·6H2O and 0.05M ZrOCl2·8H2O were mixed to obtain a precursor mixture. 1.2M trimesic acid and 0.3M 2-aminoterephthalic acid were mixed to obtain the ligand.

[0031] The precursor mixture was mixed with the ligand and hydrothermally reacted at 120°C for 12 h. After centrifugation, the mixture was washed alternately with ethanol and N,N-dimethylformamide to obtain the Fe / Zr heterostructure MOF, which is the Fe / Zr-MOF.

[0032] S2. Hierarchical Pore Structure Control: Fe / Zr heterostructure MOFs with different pore sizes of 2-3 nm, 5-7 nm, and 8-10 nm were obtained by adding CTAB, Pluronic F127 block copolymer, and PS microspheres. The mass fraction concentration of CTAB in the template control solution was 0.05%, the mass fraction concentration of Pluronic F127 block copolymer in the template control solution was 0.1%, and the concentration of PS microspheres in the template control solution was 2 mg / mL. CTAB determines the proportion of micropores, F127 determines the proportion of mesopores, and PS microspheres determine the proportion of macropores. In this embodiment, the proportions of the three different pore sizes are approximately equal. Specifically, a larger amount of microspheres in the macropores results in a stronger ability to strip asphaltenes, as asphaltenes are usually adsorbed in larger pores due to their size. In the mesopores, the proportion of organic scale and polymer blockage is large; the addition of Pluronic F127 can react with persulfate and hydrogen peroxide to generate free radical SO4· - ·OH oxidizes and degrades polymer blockages, while persulfates such as ammonium persulfate and hydrogen peroxide are used to break down polymers.

[0033] The specific process is as follows: First, add 0.05wt% CTAB surfactant to preferentially form a uniform microporous distribution, which is beneficial to the interaction between the MOF precursor and CTAB micelles; then add 0.1wt% Pluronic F127 to provide a mesoporous framework and avoid competition and interference with CTAB; finally, add 2mg / mL PS microspheres, which are large in volume and easy to aggregate, and their addition at the end can ensure uniform dispersion and reduce the impact on the first two template agents.

[0034] Reaction parameters: The precursor hydrothermal reaction temperature was 120℃ and the time was 12h. Then, after adding CTAB and Pluronic F127, the mixture was magnetically stirred at 500rpm for 20min. The stirring was considered complete when a stable vortex appeared on the liquid surface and no flocculent agglomeration was observed. Before adding PS microspheres, the mixture was ultrasonically dispersed at 40kHz and 120W for 10min at room temperature. When the dispersion was homogeneous and there was no sedimentation, the mixture was magnetically stirred at 500rpm for 20min. The stirring was considered complete when a stable vortex appeared on the liquid surface and no flocculent agglomeration was observed.

[0035] Aperture ratio: 2nm~3nm small pores account for 25%~40%, 5nm~7nm medium pores account for 35%~50%, and 8nm~10nm large pores account for 20%~35%.

[0036] The macroporous structures prepared by PS microspheres can effectively adsorb and diffuse heavy oil and asphaltenes, thereby enabling the long-chain alkyl structures on the surface of the amphiphilic nano-MOF composite carrier to interact hydrophobically with the oil phase, promoting the peeling and dispersion of oily blockages. Mesoporous structures prepared by Pluronic F127: Generate highly reactive free radical SO4· in the presence of persulfate and hydrogen peroxide. - ·OH groups are used to perform confined oxidative degradation of polymeric organic scale; among which, polymeric organic scale contains persulfate, which can act as an initiator for polymer cross-linking reactions. Alternatively, a small amount of persulfate can be injected simultaneously with the amphiphilic nano-MOF composite carrier.

[0037] The pores prepared by CTAB provide a high specific surface area and dense anchoring points, enabling the grafting of the most carboxyl and amino functional groups. The pores are rich in carboxyl and amino functional groups, which are the main sites for lipase fixation and chelation reactions. They can realize the enzymatic decomposition of organic residues and the multi-toothed complexing and dissolving effect of ethylenediaminetetramethylenephosphonic acid on inorganic scale.

[0038] S3, carboxylation and amphiphilic modification.

[0039] Fe / Zr heterostructured MOFs with different pore sizes were immersed in a 3:1 volume ratio mixture of HNO3 and hydrogen peroxide and treated at 80°C for 2 h to introduce -COOH functional groups, achieving a density of 1.2 mmol / g. The MOFs were then dispersed in toluene, and refluxed at 110°C for 6 h under nitrogen protection with 5% (w / w) 3-aminopropyltriethoxysilane to obtain surface-aminated MOFs. These MOFs were further reacted with stearoyl chloride C 18 H 35 The ClO reaction involves grafting long-chain alkyl groups, i.e., –(CH2). 17 CH3, contact angle >120°. The mass percentage of HNO3 is 65%, and the mass percentage of hydrogen peroxide is 30%.

[0040] S4. Functional component loading and immobilization.

[0041] 0.5M FeSO4 solution was injected into the MOF suspension, and 1M NaBH4 was added dropwise. Reduction deposition was carried out at pH=10. The loading of nano-zero valent iron was controlled by adjusting the initial concentration of metallic Fe so that the mass ratio of Fe in the final Fe / Zr-MOF was 15%.

[0042] S5, Preparation of amphiphilic nano-MOF composite carriers.

[0043] The amino groups on the surface of the MOF were activated using 2.5% glutaraldehyde crosslinking agent, and 10 mg / mL lipase was added. The mixture was shaken at 4°C for 12 h, and the immobilized enzyme activity retention rate was >85%, thus obtaining an amphiphilic nano-MOF composite carrier.

[0044] Example 2: A method for preparing an amphiphilic nano-MOF composite carrier, comprising the following steps.

[0045] S1, Synthesis of heterostructured Fe / Zr-MOF. Same as S1 in Example 1.

[0046] S2, hierarchical pore structure control.

[0047] Fe / Zr heterostructure MOFs with different pore sizes of 2nm~3nm, 5nm~7nm, and 8nm~10nm were obtained by adding 0.03wt% CTAB surfactant, 0.05wt% Pluronic F127 block copolymer, and 1mg / mL PS microsphere template.

[0048] S3, carboxylation and amphiphilic modification. Same as S3 in Example 1.

[0049] S4. Functional component loading and immobilization.

[0050] 0.5M FeSO4 solution was injected into the MOF suspension, and 1M NaBH4 was added dropwise. Reduction deposition was carried out under pH=10 conditions. The loading of nano-zero valent iron was controlled by adjusting the initial concentration of metallic Fe, and the final mass percentage of Fe / Zr-MOF was 10%.

[0051] S5, Preparation of amphiphilic nano-MOF composite carrier. Same as S5 in Example 1.

[0052] Example 3: A method for preparing an amphiphilic nano-MOF composite carrier, comprising the following steps.

[0053] S1, Synthesis of heterostructured Fe / Zr-MOF. Same as S1 in Example 1.

[0054] S2, hierarchical pore structure control. Same as S2 in Example 2.

[0055] S3, carboxylation and amphiphilic modification. Same as S3 in Example 1.

[0056] S4. Functional component loading and immobilization.

[0057] 0.5M FeSO4 solution was injected into the MOF suspension, and 1M NaBH4 was added dropwise. Reduction deposition was carried out under pH=10 conditions. The loading of nano-zero valent iron was controlled by adjusting the initial concentration of metallic Fe, and the final mass percentage in Fe / Zr-MOF was 5%.

[0058] S5, the preparation of the amphiphilic nano-MOF composite carrier, is the same as S5 in Example 1.

[0059] The particle size distribution diagrams of Examples 1 to 3 above are as follows: Figure 1 As shown in Table 1.

[0060] Table 1. Particle size distribution curves of Examples 1-3 To further illustrate the effect of the amphiphilic nano-MOF composite carrier of the present invention, the following experiments were conducted.

[0061] 1. For heavy oil / asphalt.

[0062] Static asphalt stripping experiment: A pre-aged oil film glass slide was weighed and then added to the three amphiphilic nano-MOF composite carrier solutions prepared in Examples 1-3. The solutions were prepared with distilled water to obtain a mass percentage concentration of 0.3% for each slide until the glass slide was completely submerged in the liquid. The slide was then sealed and placed in a 60°C oven for 48 hours. The slide was then removed and weighed, and the static asphalt stripping rate of the glass slide was calculated. The results are shown in Table 2.

[0063] .

[0064] Table 2. Asphalt stripping test of amphiphilic nano-MOF composite carrier solution. CT scan of heavy oil intrusion experiment.

[0065] A standard sandstone core, 5 cm in length and 2.5 cm in diameter, was immersed in a 0.3% (w / w) MOF aqueous solution prepared using distilled water as the solvent and the amphiphilic nano-MOF composite carriers from Examples 1-3 as the solute. After 48 h and 96 h of percolation, the cores were retrieved and subjected to CT scans. The closer the CT scan image is to blue, the more heavy oil is present; the closer it is to red, the higher the penetration depth of the amphiphilic nano-MOF composite carrier solution. The results are as follows: Figure 2 As shown.

[0066] 2. For organic scale.

[0067] Static polymer degradation test: M was prepared using water n A polymer solution with a mass concentration of 25 million and an apparent viscosity of 1280 mPa·s was prepared at a concentration of 1%. After gelation, the viscosity of the polymer solution was measured. Then, 0.3% by mass of the three amphiphilic nano-MOF composite carrier solutions from Examples 1-3 were added, and the mixture was stirred thoroughly for 30 min before testing the viscosity of the degraded polymer. The same concentration was used for all three examples. The results are shown in Table 3.

[0068] Table 3 Polymer degradation test of amphiphilic nano-MOF composite carrier solution M was prepared with water. n A polymer solution with a concentration of 1% and an apparent viscosity of 25 million mPa·s was prepared. After gelation, the viscosity of the polymer solution was measured. Then, different concentrations of the amphiphilic nano-MOF composite carrier solution from Example 1 were added, and the mixture was stirred thoroughly for 30 minutes before testing the viscosity of the degraded polymer. The results are shown in Table 4. The antidote concentration refers to the concentrations of the amphiphilic nano-MOF composite carrier solution from Example 1.

[0069] Table 4 Viscosities of amphiphilic nano-MOF composite carrier solutions at different concentrations As can be seen from Table 4, the amphiphilic nano-MOF composite carrier solution with a mass percentage concentration of 0.3% already has sufficient ability to degrade organic scale, i.e. polymers, with a polymer viscosity reduction rate of over 99%.

[0070] Core polymer unblocking test: Prepare a 1% (w / w) concentration of M polymer solution using clean water. n A polymer solution with a mass concentration of 25 million and an apparent viscosity of approximately 500 mPa·s was used. Artificial square cores, 30 cm long, 4.5 cm wide, and 4.5 cm high, were placed in a specialized holder and saturated with water. Then, a 1% (w / w) polymer solution was injected until stable polymerization was observed at the outlet. The cores were then aged in a 70°C oven for 24 hours. After aging, 0.3 PV of the amphiphilic nano-MOF composite carrier solution prepared in Example 1, with mass percentage concentrations of 0.1%, 0.3%, and 0.5%, was injected into the inlet of the core holder. The inlet and outlet of the core holder were then closed for 12 hours. After reopening the inlet and outlet, subsequent water flooding of 0.7 PV was performed. The produced fluid was collected at different times, and the solution viscosity was measured using a rotational viscometer. The results are shown in the figure below. Figure 3 Show.

[0071] from Figure 3It can be seen that the results of the dynamic displacement viscosity reduction and unblocking experiment are highly consistent with the results of the static polymer degradation test. When the mass percentage concentration is 0.1%, 0.3%, and 0.5%, the viscosity of the produced fluid decreases slightly with the injection of the amphiphilic nano-MOF composite carrier solution. After injecting 0.3 PV and shutting in the well for 12 hours, the polymer begins to degrade rapidly. In the subsequent water drive stage, the viscosity of the produced fluid gradually decreases. Finally, the polymer viscosity at the outlet of the 0.3% mass percentage concentration amphiphilic nano-MOF composite carrier solution drops to 4.97 mPa·s, which is slightly lower than the viscosity of 4.84 mPa·s of the 0.5% mass percentage concentration amphiphilic nano-MOF composite carrier solution, but the difference is not significant. The polymer viscosity at the outlet of the 0.1% mass percentage concentration amphiphilic nano-MOF composite carrier solution drops to only about 40 mPa·s.

[0072] 2. For inorganic scale.

[0073] Static calcium carbonate corrosion experiment: Calcium carbonate sample and 10% (by mass percentage) aqueous solution of amphiphilic nano-MOF composite carrier from Examples 1-3 were added at a mass ratio of 1:100. The mixture was kept at 70°C for 60 hours, and the corrosion rate was calculated every 12 hours. The results are as follows: Figure 3 As shown.

[0074] .

[0075] in, The total mass of the reaction vessel, calcium carbonate sample, and amphiphilic nano-MOF composite carrier solution before the reaction begins; This represents the total mass of the reaction vessel, calcium carbonate sample, and amphiphilic nano-MOF composite carrier solution after the reaction. From... Figure 4 It can be seen that the amphiphilic nano-MOF composite carrier solution of Example 1 exhibited the fastest dissolution rate for calcium carbonate, reaching 79.08% after 12 hours, while Examples 2 and 3 only achieved 54.77% and 48.78%, respectively. After 24 hours, the dissolution rate of the amphiphilic nano-MOF composite carrier solution of Example 1 for calcium carbonate exceeded 90%, with a final dissolution rate of 92.22%, which was greater than the 89.55% of Example 2 and 83.56% of Example 3. The dissolution effect of the calcium carbonate sample at different times in Example 1 is shown below. Figure 5 As shown.

[0076] Static quartz (rock framework) dissolution experiment: Calcium carbonate sample, 10% (w / w) amphiphilic nano-MOF composite carrier aqueous solution from Example 1, and 10% (w / w) argylic acid corrosion inhibitor were added at a mass ratio of 1:20. The mixture was kept at 70°C for 250 minutes, and the dissolution rate was calculated every 25 minutes. Results are as follows: Figure 5 As shown in the figure. The 10% concentration of the acid corrosion inhibitor was purchased from Ningbo Boneng Chemical Technology Co., Ltd.

[0077] ; in, The total mass of the reaction vessel, core quartz fragments, and amphiphilic nano-MOF composite carrier solution before the reaction begins; The total mass of the reaction vessel, core quartz fragments, and amphiphilic nano-MOF composite carrier solution after the reaction.

[0078] from Figure 6 It can be seen that the soil acid corrosion inhibitor has a strong acid-rock reaction, rapidly and completely dissolving the quartz stratum framework, easily causing serious damage to the sand body structure, with a final dissolution rate of 13.93%; the amphiphilic nano-MOF composite carrier aqueous solution has a slow dissolution rate and a long duration, effectively protecting the loose sandstone framework and preventing secondary damage due to severe dissolution, with a dissolution rate of 0.27%; the amphiphilic nano-MOF composite carrier solution has a low dissolution rate on the rock framework and a mild dissolution process, which greatly alleviates the serious sand production problem caused by the loose cementation of the target stratum.

[0079] Static mud-blocking dissolution experiment: Rock fragments with high mud content were ground into powder, and then added to the powdered rock fragments, 10% amphiphilic nano-MOF composite carrier and 10% argillaceous acid corrosion inhibitor from Example 1 at a mass ratio of 1:20. After standing at room temperature for 1 hour, the mixture was taken out and dried, and the dissolution rate was calculated. The results are shown in Table 5.

[0080] ; in, The total mass of the reaction vessel, mudstone fragments, and amphiphilic nano-MOF composite carrier solution before the reaction begins; The total mass of the reaction vessel, mudstone fragments, and amphiphilic nano-MOF composite carrier solution after the reaction.

[0081] Table 5. Dissolution of mud by different unblocking agent systems The results in Table 5 show that the amphiphilic nano-MOF composite carrier solution is more effective than soil acid corrosion inhibitors in dissolving rock cuttings, with a dissolution rate as high as 48%. The amphiphilic nano-MOF composite carrier solution is also effective in removing clay contamination and can be used to remove inorganic blockage in the near-wellbore area caused by clay migration.

[0082] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An amphiphilic nano-MOF composite carrier, characterized in that, The amphiphilic nano-MOF composite support is obtained by solvothermal method to obtain Fe / Zr heterostructure MOF, and the pore size is controlled by template agent to obtain Fe / Zr heterostructure MOF with different pore sizes; the diameter of the different pores is 2nm~3nm, 5nm~7nm and 8nm~10nm; Carboxylic acid groups were grafted onto Fe / Zr heterostructure MOFs via oxidation, and then surface-aminated MOFs were obtained through silane coupling reaction. After grafting alkyl groups onto them, surface-modified MOFs were obtained. Nanoparticle zero-valent iron was loaded onto a surface-modified MOF using a reduction method, and lipase was immobilized on the surface-modified MOF using a covalent anchoring method to obtain the amphiphilic nano-MOF composite carrier.

2. The amphiphilic nano-MOF composite carrier according to claim 1, characterized in that, The template agent is hexadecyltrimethylammonium bromide, Pluronic F127 block copolymer, and polystyrene microspheres; the mass of hexadecyltrimethylammonium bromide is 0.01%~0.05% of the mass of Fe / Zr heterostructure MOF, the mass of Pluronic F127 block copolymer is 0.05%~0.1% of the mass of Fe / Zr heterostructure MOF, and the concentration of polystyrene microspheres in Fe / Zr heterostructure MOF is 0.5mg / mL~2.5mg / mL; The hexadecyltrimethylammonium bromide is used to form channels with a diameter of 2 nm to 3 nm; The Pluronic F127 block copolymer is used to form channels with a diameter of 5 nm to 7 nm; The polystyrene microspheres are used to form channels with a diameter of 8 nm to 10 nm.

3. A method for preparing the amphiphilic nano-MOF composite carrier according to any one of claims 2, characterized in that, Includes the following steps: Iron ion precursor solution, zirconium ion precursor solution and ligands were mixed and subjected to a solvothermal reaction to obtain Fe / Zr heterostructure MOF; wherein the ligands were pyromellitic acid and 2-aminoterephthalic acid. By sequentially adding the template agent hexadecyltrimethylammonium bromide, Pluronic F127 block copolymer and polystyrene microspheres to Fe / Zr heterostructure MOF, Fe / Zr heterostructure MOF with different pore sizes were obtained. Fe / Zr heterostructure MOFs with different pore sizes were immersed in acid and subjected to oxidation to achieve a carboxylic acid group concentration of 0.8 mmol / g to 1.3 mmol / g on the grafted Fe / Zr heterostructure MOFs. The MOFs were then dispersed in an organic solvent, a silane coupling agent was added, and the mixture was refluxed at 105℃ to 110℃ for 4 to 8 hours to obtain surface-aminated MOFs. The surface-aminated MOFs were then reacted with stearoyl chloride to graft alkyl groups onto the surface-aminated MOFs, resulting in surface-modified MOFs. The suspension of surface-modified MOF was mixed with FeSO4 solution, and NaBH4 was added to carry out a reduction deposition reaction, so that nano-zero valent iron was loaded on the surface-modified MOF. The amino groups on the surface of the surface-modified MOF were activated with glutaraldehyde, and then lipase was added to carry out an immobilization reaction to obtain the amphiphilic nano-MOF composite carrier.

4. The preparation method according to claim 3, characterized in that, The molar ratio of the iron ion precursor solution, the zirconium ion precursor solution, and the ligand is 0.05M~0.15M : 0.03M~0.08M : 1.0M~1.8M; The molar ratio of pyromellitic acid to 2-aminoterephthalic acid is 1.0M~1.5M:0.2M~0.4M.

5. The preparation method according to claim 3, characterized in that, The conditions for the solvothermal reaction are as follows: temperature 100℃~130℃, time 8h~16h; After the solvothermal reaction, centrifugation and alternating washing with ethanol and N,N-dimethylformamide yielded the Fe / Zr heterostructure MOF.

6. The preparation method according to claim 3, characterized in that, The polystyrene microspheres have a particle size of 0.2 μm to 0.5 μm.

7. The preparation method according to claim 3, characterized in that, The acid solution is obtained by mixing hydrogen peroxide and nitric acid in a volume ratio of 3:1; the organic solvent is toluene, and the silane coupling agent is 3-aminopropyltriethoxysilane.

8. The preparation method according to claim 3, characterized in that, The molar ratio of the surface-modified MOF suspension, FeSO4 solution, and NaBH4 was 1:0.4~0.7:0.8~1.

2. The glutaraldehyde has a mass percentage of 2.5%, the lipase has a concentration of 5 mg / mL to 15 mg / mL, and the suspension of surface-modified MOF has a concentration of 5 mg / mL to 20 mg / mL. The volume ratio of glutaraldehyde, surface-modified MOF suspension, and lipase was 1:2:1~3.

9. The application of the amphiphilic nano-MOF composite carrier as described in claim 2 in unclogging oil, gas and water wells.

10. The application according to claim 9, characterized in that, The unblocking of oil, gas and water wells includes unblocking of heavy oil / asphalt, organic scale, and inorganic scale.

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