A solid capsule with corrosion inhibition and ion adsorption functions and a preparation method thereof

Abstract

The application discloses a solid capsule with corrosion inhibition and ion adsorption functions and a preparation method thereof, and belongs to the technical field of oil and gas field chemistry. The solid capsule can deliver 1H-benzotriazole (BTA) to a corrosion area of an oil well for targeted corrosion inhibition through a curing reaction of an epoxy resin (EP) and polyethylene imine (PEI), and dense amino groups (-NH2 and -NH-) in a molecular chain of the polyethylene imine (PEI) endow the polyethylene imine (PEI) with strong chelation and electrostatic adsorption capabilities. The solid capsule with corrosion inhibition and ion adsorption functions has a three-dimensional network structure, and through swelling, the structure is fully stretched, the corrosion inhibitor is released, and at the same time, the amino groups in the molecular chain of the PEI are exposed to water, so that the diffusion and combination of heavy metal ions are accelerated. Therefore, a controlled release system with both corrosion inhibition and ion adsorption functions is realized, which provides an innovative solution for solving the problems of corrosion and ion pollution in a complex environment of an oil and gas field.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas field chemical technology, specifically relating to a solid capsule with corrosion inhibition and ion adsorption functions and its preparation method. Background Technology

[0002] Metal corrosion is a type of damage that occurs to metallic materials in the external environment, leading to a decrease in the material's strength, plasticity, toughness, and other mechanical properties. Currently, one of the most suitable technical methods for protecting metals from corrosion is the addition of corrosion inhibitors; even a small amount of inhibitor can achieve excellent corrosion inhibition. In oilfield applications such as oil extraction, high-temperature environments are common, especially in downhole pipelines, where corrosion problems on metal equipment are significantly exacerbated. Frequent replenishment of corrosion inhibitors not only results in high operating costs but may also lead to uneven application causing localized corrosion, and it fails to address the problem of excessive harmful ions in produced water causing water pollution. On the other hand, existing ion adsorption materials or technologies primarily focus on ion removal, offering negligible protection against metal corrosion.

[0003] Application No. 202410815886.9 discloses a method for preparing a long-protection-cycle ultra-deep well solid corrosion inhibitor. The method involves mixing an imidazoline corrosion inhibitor with an N-containing hydrochloride corrosion inhibitor, then adding an auxiliary corrosion inhibitor and mixing to obtain an intermediate corrosion inhibitor. The intermediate corrosion inhibitor is then mixed with a curing agent and stirred, poured into a mold, and shaped to obtain the long-protection-cycle ultra-deep well solid corrosion inhibitor.

[0004] Application No. 202010108825.0 discloses a slow-release solid corrosion inhibitor, its preparation method, and its application. The slow-release solid corrosion inhibitor is composed of 30%–55% composite corrosion inhibitor, 1%–5% organic filler, 25%–45% functional weighting agent, 10%–20% binder, and 0.1%–0.5% hydrophobic coating material by weight. The composite corrosion inhibitor, organic filler, functional weighting agent, and binder are added to a mixing tank and stirred until homogeneous. The resulting mixture is then injection molded to obtain particles with a length of 5–10 mm and a diameter of 5–8 mm. A hydrophobic coating material is added to the particles, and the mixture is stirred until homogeneous to obtain the slow-release solid corrosion inhibitor. However, the hydrophobic coating material has poor coating properties for the solid particles. Due to the weak interaction force between the coating shell and the solid particles, the corrosion inhibitor is released prematurely, affecting the slow-release effect.

[0005] The aforementioned patents suffer from low corrosion inhibition efficiency, poor corrosion inhibition efficiency due to premature release of the corrosion inhibitor, and lack of ion adsorption effect. Therefore, this invention, based on the curing reaction of EP and PEI, enhances the high-temperature resistance of EP after curing, enabling long-term controllable release of the corrosion inhibitor and solving the problems of easy loss and uncontrollable release of traditional solid corrosion inhibitors under high-temperature conditions. While improving corrosion inhibition capacity, this invention utilizes the electrostatic effect of PEI amino groups to enhance the ion adsorption capacity of the material for adsorbing harmful ions in produced water, thus preparing a solid capsule with dual functions of corrosion inhibition and ion adsorption. Summary of the Invention

[0006] The purpose of this invention is to provide a solid capsule that can effectively protect against metal corrosion and provide certain ion adsorption performance, as well as a method for preparing the same, thereby solving the current hidden dangers of metal corrosion and improving ion adsorption capacity.

[0007] To achieve the above objectives, this specification provides a multifunctional solid capsule design method with corrosion inhibitor release and ion adsorption capabilities. The method is characterized by utilizing the curing reaction of epoxy resin (EP) and polyethyleneimine (PEI) to form a solid capsule, and utilizing the gel three-dimensional network structure of the solid capsule to facilitate the entry and exit of the corrosion inhibitor. PEI is amino-based, enabling the adsorption of heavy metal ions.

[0008] The implementation process of this invention is briefly explained below.

[0009] (I) This invention relates to a solid capsule with corrosion inhibition and ion adsorption functions and its preparation method, characterized in that:

[0010] (1) Add 1g EP and 2g PEI to a beaker.

[0011] (2) Weigh 1.29g BTA, add 0.5ml anhydrous ethanol, sonicate to dissolve, and then add to a beaker containing EP and PEI.

[0012] (3) Stir well and add the mixture into the mold.

[0013] (4) Place the mold in a drying oven.

[0014] (5) Remove the mold, cool it, and remove the solid capsules EP / PEI / BTA.

[0015] Furthermore, in step (i) (1), the amount of anhydrous ethanol is 0.5 ml.

[0016] Furthermore, in steps (i) and (2), the ultrasonic power is 750 W.

[0017] Furthermore, in steps (i) and (3), the mold is a spherical mold with a diameter of 0.5 cm and a depth of 0.6 cm.

[0018] Furthermore, in step (i) (3), a 1ml syringe is used to inject into the mold.

[0019] Furthermore, in steps (i) and (4), the temperature of the drying oven is 60°C.

[0020] Furthermore, in steps (i) and (4), the drying time is 12 hours.

[0021] The EP (polyethylene imine) of this invention has no loading capacity and cannot self-cur. However, when combined with PEI (polyethylene imine), a curing reaction occurs. The mechanism is as follows: a nucleophilic ring-opening addition reaction between amine and epoxy groups. In the abundant primary and secondary amine groups on the polyethyleneimine molecular chain, the lone pair electrons on the nitrogen atom act as nucleophiles, attacking the less sterically hindered carbon atoms on the epoxy ring of the epoxy resin, leading to the opening of the three-membered ring and the formation of a stable carbon-nitrogen covalent bond. Simultaneously, the generated hydroxyl groups can further catalyze reactions or participate in hydrogen bonding. This reaction requires no additional catalyst and can be carried out at room temperature or under heating conditions. Through the stepwise addition polymerization of amine and epoxy groups, a highly cross-linked three-dimensional network structure is ultimately formed.

[0022] Compared with the prior art, the present invention brings the following beneficial technical effects: (1) The present invention breaks through the bottleneck of existing oilfield corrosion inhibition and ion adsorption by designing the composite structure of "EP / PEI / BTA".

[0023] (2) Existing technologies are prone to severe corrosion at high temperatures and release too quickly, resulting in low corrosion inhibition efficiency and short duration. This invention solves this problem by solidifying EP with PEI: the high-temperature corrosion zone of downhole oil pipelines forms an acidic environment due to metal oxidation reaction. The PEI in the solid capsule is protonated and positively charged under acidic conditions, which can electrostatically adsorb with the negatively charged metal corrosion surface, realizing the long-term release and enrichment of corrosion inhibitor in the corrosion zone.

[0024] (3) Existing technologies cannot simultaneously solve the core problems of pipeline corrosion and excessive ions in produced water, requiring additional adsorbents or corrosion inhibitors, which increases operating costs and complexity. This invention utilizes the exposed PEI in solid capsules, which is protonated and positively charged under acidic conditions, to electrostatically adsorb negatively charged harmful ions, thereby significantly reducing the content of harmful ions in produced water and achieving water resource treatment. Attached Figure Description

[0025] This description characterizes the examples based on solid capsules made during the experimental process and describes the experimental results.

[0026] Figure 1 This is a SEM image of the solid capsule EP / PEI / BTA in Example 1 of the present invention.

[0027] Figure 2The thermogravimetric diagram of the solid capsule EP / PEI / BTA in Example 1 of the present invention.

[0028] Figure 3 The image shows the infrared spectrum of the solid capsule EP / PEI / BTA in Example 1 of this invention.

[0029] Figure 4 The impedance values ​​are those of the solid capsules EP / PEI / BTA in this embodiment of the invention.

[0030] Figure 5 The removal rate of Cr(VI) by the solid capsule EP / PEI / BTA in Example 1 of this invention is given. Detailed Implementation

[0031] This invention specifically relates to a solid capsule with corrosion inhibition and ion adsorption functions and its preparation method.

[0032] The BTA mentioned in this invention is an abbreviation for 1H-benzotriazole, used as a corrosion inhibitor.

[0033] The PEI mentioned in this invention is an abbreviation for polyethyleneimine.

[0034] The EP mentioned in this invention is an abbreviation for E44 type epoxy resin.

[0035] All the raw materials mentioned in this invention can be purchased through commercial channels.

[0036] The specific composition of the solid capsules is shown in Table 1.

[0037] Table 1. Composition of solid capsules

[0038] Components Specification Polyethyleneimine MW 10000, 99% Anhydrous ethanol 99.8% Epoxy resin E-44 1H-benzotriazole 99%

[0039] The preparation method will be described in detail below with reference to specific embodiments.

[0040] Example 1: First, 1g of EP and 2g of PEI were added to a beaker. 1.29g of BTA was weighed and added to 0.5ml of anhydrous ethanol. The mixture was sonicated until completely dissolved. Then, the solution was added to the beaker containing EP and PEI, and stirred with a glass until completely mixed. Next, the mixture was quickly injected into a spherical mold with a diameter of 0.5cm and a depth of 0.6cm using a syringe. After all the mixture was added to the mold, the mold was placed in a drying oven at 60℃ and left to stand for 12 hours. After cooling to room temperature, the solidified EP / PEI / BTA capsules were removed and ready for use.

[0041] The solid capsules of EP / PEI / BTA prepared in this embodiment are transported along with the acidizing fluid to oil well areas and pipeline corrosion-prone regions via a wellhead injection device. When the pipeline corrosion area faces a localized acidic environment, the exposed PEI on the surface of the solid capsules protonates under acidic conditions, carrying a positive charge. This positive charge then electrostatically adsorbs onto the negatively charged metal corrosion surface, resulting in slight swelling under acidic conditions and providing a channel for the release of the BTA corrosion inhibitor. In the initial stage of acidizing operations, the release rate is high, rapidly inhibiting the corrosion reaction. As corrosion slows and the ambient pH increases, the release rate decreases, achieving dynamic release of the corrosion inhibitor. The protonated PEI layer on the surface of the solid capsules carries a positive charge, which electrostatically adsorbs onto negatively charged ions, removing harmful ions from the water and addressing water pollution issues.

[0042] Example 2: The difference from Example 1 is that 1g EP and 1g PEI were added to a beaker, and 0.86g BTA was weighed out.

[0043] Example 3: The difference from Example 1 is that 1g EP and 0.33g PEI were added to a beaker, and 0.57g BTA was weighed out.

[0044] Example 4: The difference from Example 1 is that 1g EP and 0.167g PEI were added to the beaker, and 0.5g BTA was weighed out.

[0045] Comparative Example 1: A capsule-type solid corrosion inhibitor capable of long-term, stable release of the corrosion inhibitor. The capsule-type solid corrosion inhibitor is obtained by polymerizing halloysite nanotubes and polyelectrolytes, then dispersing them with the corrosion inhibitor and negatively charged polyacid electrolytes after ionization. Under optimal conditions, its highest corrosion inhibition efficiency is 93%, which decreases over time; and it exhibits no ion adsorption effect.

[0046] Comparative Example 2: A method for preparing a long-term protection cycle solid corrosion inhibitor for ultra-deep wells. A quaternary ammonium salt imidazoline corrosion inhibitor is mixed evenly with amantadine hydrochloride and / or diphenhydramine hydrochloride corrosion inhibitors. Then, an auxiliary corrosion inhibitor is added and mixed, followed by mixing with a curing agent. The mixture is then poured into a mold to form the long-term protection cycle solid corrosion inhibitor for ultra-deep wells. Its overall corrosion inhibition rate is above 85%, and it exhibits no ion adsorption effect.

[0047] The solid capsules EP / PEI / BTA prepared in Examples 1-4 above were tested. EP, as the network framework, exhibits a denser structure with increased content, hindering the release and diffusion of the internal corrosion-inhibiting components, leading to a decrease in release rate and corrosion inhibition efficiency. PEI, on the other hand, is the functional core; its increased content provides more active amino groups, significantly enhancing the adsorption and integration capacity for ions, thereby improving ion removal rate. A comprehensive analysis of the embodiments and comparative examples clearly highlights the advantages of this invention. Under optimal conditions, the highest corrosion inhibition efficiency of this invention is over 95%, exceeding that of Comparative Example 2. Furthermore, the highest removal rate of Cr(VI) ions under optimal conditions is 97.1%.

[0048] Any parts not mentioned in this invention can be achieved by referring to existing technologies.

[0049] It should be noted that any equivalent or obvious modifications made by those skilled in the art under the guidance of this specification should be within the scope of protection of this invention.

Claims

1. A solid capsule with corrosion inhibition and ion adsorption functions and its preparation method, belonging to the field of oil and gas field chemical technology; the solid capsule is cured by epoxy resin (EP) and polyethyleneimine (PEI), and loaded with 1H-benzotriazole (BTA) to deliver BTA to the corrosion area of ​​the oil well for targeted corrosion inhibition, and the dense amines (-NH2, -NH-) in the polyethyleneimine (PEI) molecular chain endow it with strong chelation and electrostatic adsorption capabilities.

2. A solid capsule with corrosion inhibition and ion adsorption functions and its preparation method, (I) The preparation method of the present invention is characterized in that: (1) Add 1g EP and 2g PEI to a beaker. (2) Weigh 1.29g of BTA, add anhydrous ethanol, sonicate to dissolve, and add to a beaker containing EP and PEI. (3) Stir well and add the mixture into the mold. (4) Place the mold in a drying oven. (5) Remove the mold, cool it, and remove the solid capsules EP / PEI / BTA.

3. The preparation method according to claims 1 and 2, characterized in that: In steps (i) and (2), the amount of anhydrous ethanol is 0.5 ml.

4. The preparation method according to claims 1 and 2, characterized in that: In steps (i) and (2), the ultrasonic power is 750 W.

5. The preparation method according to claims 1 and 2, characterized in that: In steps (i) and (3), the mold is a spherical mold with a diameter of 0.5 cm and a depth of 0.6 cm.

6. The preparation method according to claims 1 and 2, characterized in that: In steps (a) and (3), a 1ml syringe is used to inject into the mold.

7. The preparation method according to claims 1 and 2, characterized in that: In steps (i) and (4), the temperature of the drying oven is 60 ℃.

8. The preparation method according to claims 1 and 2, characterized in that: In steps (i) and (4), the drying time in the drying oven is 12 hours.

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