Antioxidant corrosion inhibitor for oil well and preparation method thereof

Abstract

The invention relates to an antioxidant corrosion inhibitor for an oil well and a preparation method of the antioxidant corrosion inhibitor, and belongs to the technical field of petrochemical corrosion and protection. The preparation method of the antioxidant corrosion inhibitor comprises the following steps: dissolving thiourea in an alcohol organic solvent, heating to 40-60 DEG C, adding trimesic acid and a catalyst, heating and refluxing for 6-8 hours, distilling and purifying, washing, and drying in vacuum to obtain an intermediate; and dissolving glucose in water, heating to 30-35 DEG C, adding sodium hydroxide and the intermediate, carrying out heating reflux reaction for 6-8 hours, and carrying out reduced pressure rotary evaporation to obtain the antioxidant corrosion inhibitor. The antioxidant corrosion inhibitor disclosed by the invention has the advantages of being difficult to decompose at high temperature, strong in adsorption, good in dissolution and dispersibility in hypersalinity simulated formation water and the like, and has a wide application prospect in oil well exploitation.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of petrochemical corrosion and protection, and particularly relates to an oxygen-resistant corrosion inhibitor for oil wells and a preparation method thereof. BACKGROUND

[0002] In recent years, due to the wide application of the oilfield injection water system, produced water system, sewage system and air foam drive system, more and more oxygen enters the oil-water system, causing pipeline failure and injection water quality decline. Studies have shown that the uniform corrosion rate of dissolved oxygen is 80 times that of CO2 and 400 times that of H2S. Extremely low concentration of oxygen (less than 1 mg / L) in the solution can cause extremely serious corrosion. If oxygen and CO2 or H2S gas exist in the solution at the same time, synergistic corrosion will occur, and the corrosion rate will rise sharply. A large number of experiments have proved that the strong oxidizing property of O2 can directly oxidize Fe 2+ to Fe 3+ , and Fe 3+ reacts with the cathode reaction product OH - to form Fe(OH)3 precipitate. Part of the Fe(OH)3 will dehydrate to form FeO(OH) or Fe2O3·H2O at high temperature. However, the corrosion products of FeO(OH) and Fe2O3 are loose and porous, the formed oxide film is not dense, has poor adhesion on the surface of the steel body, and is easily washed off by the flowing medium in the pipeline. At the same time, Cl - in the corrosion medium can easily penetrate the film and cannot effectively protect the steel.

[0003] At present, adding corrosion inhibitors and deoxidizers is still an important way to solve pipeline corrosion. However, there are few corrosion inhibitors suitable for oxygen corrosion. The corrosion inhibition rate of most anti-CO2 or H2S gathering and transportation corrosion inhibitors is less than 50% in the environment containing dissolved oxygen. In the early stage, deoxidizers were used to remove dissolved oxygen in water. However, the amount of deoxidizer gradually increases with the increase of the content of dissolved oxygen, the corrosion prevention cost is greatly improved, and the deoxidizer cannot continuously remove the gas contained in the continuous gas injection. The subsequently developed oxygen-resistant corrosion inhibitors are mainly applied to drilling fluids and oil production plants. Most of their components are organic phosphonic acids, which can easily cause eutrophication of water bodies and further pollute the environment. The addition of amine and polymer corrosion inhibitors has problems such as decomposition, oxidation, poor dissolution and dispersion in high temperature and high pressure, high salinity formation water.

[0004] Based on the above problems, in order to deal with the oxygen corrosion problem caused by the increasing content of dissolved oxygen in the pipeline, oxygen-resistant corrosion inhibitors for different environments need to be developed to reduce the corrosion prevention cost and mitigate the harm caused by oxygen corrosion. SUMMARY

[0005] In view of the deficiencies of the prior art, the present application provides an oxygen-resistant corrosion inhibitor, which has excellent oxygen stability, temperature resistance, good solubility and adsorption stability in a high-oxygen-content and high-salinity corrosive medium environment.

[0006] In a first aspect, the present application provides an oxygen-resistant corrosion inhibitor having a structure as shown in formula (I): (I).

[0007] In a second aspect, the present application provides a preparation method of the oxygen-resistant corrosion inhibitor, comprising the following steps: S1, dissolve thiourea in an alcohol organic solvent, heat to 40-60 DEG C, add trimesic acid, acid catalyst, heat to reflux for 6-8h, and then purify by distillation, wash, and vacuum dry to obtain an intermediate; S2, dissolve glucose in water and heat to 30-35 DEG C, add sodium hydroxide and the intermediate, heat to reflux for 6-8h, and then reduce pressure and rotary evaporate to obtain the oxygen-resistant corrosion inhibitor.

[0008] Further, the molar ratio of the thiourea, trimesic acid and catalyst in step S1 is (3-4):1:0.2.

[0009] Further, the alcohol organic solvent in step S1 is 2-3 times of the mass of the reaction raw materials, and the reaction raw materials are thiourea and trimesic acid.

[0010] Further, the alcohol organic solvent in step S1 is any one of ethanol and methanol.

[0011] Further, the catalyst in step S1 is any one of acetic acid and formic acid.

[0012] Further, the distillation purification condition in step S1 is that the distillation temperature is 80-90 DEG C and the time is 1-3h.

[0013] Preferably, the distillation purification condition is that the distillation temperature is 85 DEG C and the time is 2h.

[0014] Further, the washing in step S1 is washing 2-5 times with a detergent; and the detergent is ethanol or methanol.

[0015] Further, the vacuum drying condition in step S1 is that the drying temperature is room temperature, the vacuum degree is 1-2 KPa, and the time is 2-4h.

[0016] Preferably, the vacuum drying condition is that the drying temperature is room temperature, the vacuum degree is 1.325 KPa, and the time is 3h.

[0017] Further, the synthesis process of the intermediate in step S1 is as follows: .

[0018] Further, the molar ratio of glucose, sodium hydroxide and intermediate in step S2 is (3-4):0.5:1.

[0019] Further, the conditions of the reduced pressure rotary evaporation in step S2 are: temperature is 60-80℃, reduced pressure rotary evaporation concentration time is 15-45min, and rotation speed range is 80-150rmp.

[0020] Preferably, the conditions of the reduced pressure rotary evaporation are: temperature is 70℃, reduced pressure rotary evaporation concentration time is 30min, and rotation speed range is 100rmp.

[0021] Further, the synthesis process of the anti-oxygen corrosion inhibitor in step S2 is: .

[0022] In a third aspect, the application provides an application of the anti-oxygen corrosion inhibitor in oil well exploitation.

[0023] Compared with the prior art, the application has the following beneficial effects: (1) The anti-oxygen corrosion inhibitor of the application is composed of a polar group with N, S and other atoms with large electronegativity as the center and a non-polar group composed of C and H atoms, and belongs to an adsorption type corrosion inhibitor, which can quickly adsorb on the metal surface to form an oxidation film and exhibit excellent corrosion inhibition effect.

[0024] (2) The anti-oxygen corrosion inhibitor of the application forms multiple adsorption centers on the surface of a carbon steel matrix. Among them, the thiourea group can chelate with Fe 3+ , Ca 2+ , Mg 2+ and other metal cations, thereby hindering the scaling tendency in high salinity water. Secondly, the C=S double bond and N and S elements can provide electrons to form a coordination bond with the empty orbital of Fe, form multiple point adsorption and firmly adsorb on the surface of the carbon steel, the non-polar group is arranged in a direction, and a layer of hydrophobic film is formed to hinder the corrosion reaction of the carbon steel matrix. In addition, the C=S double bond and -OH have reducing property, and can also consume dissolved oxygen in water, thereby enhancing the anti-oxygen effect.

[0025] (3) The anti-oxygen corrosion inhibitor of the application is not easy to decompose under high temperature and high pressure, has good solubility and dispersibility in high salinity simulated formation water, and can better inhibit the oxygen corrosion of A3 carbon steel and N80 carbon steel in high temperature and high salinity simulated formation water, so the anti-oxygen corrosion inhibitor can effectively solve the problem of oxygen corrosion of oil wells.

[0026] Additional features and advantages of the present application will be set forth in the description that follows, and in part will be apparent from the description, or can be learned by practice of the application. The objectives and other advantages of the present application will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. DETAILED DESCRIPTION

[0027] In order to make the objectives, technical solutions and advantages of the present application clearer, the embodiments of the present application will be described in detail below with specific examples. The technical terms and scientific terms used in the present application have the meanings commonly understood by those skilled in the art of the present application, unless otherwise defined. Those skilled in the art can make various improvements and changes to the specific embodiments of the present application described in the specification without departing from the concept of the present application, and these all fall within the protection scope of the present application. The raw materials used in the present application are all commercially available unless otherwise specified.

[0028] Example 1 A preparation method of an antioxidant corrosion inhibitor, comprising the following steps: S1, in a five-necked flask equipped with a thermometer, a temperature sensing couple, a stirrer and a reflux condenser, thiourea (0.15 mol, 11.42 g) was dissolved in 50 ml of ethanol solvent, heated to 50℃, after dissolution, uniformly tribasic acid (0.05 mol, 10.51 g) and acetic acid (0.01 mol, 0.6 g) were added while stirring, and heated to reflux for 6 h; Distillation purification was carried out using a distillation device until no water and excess solvent was produced, the distillation temperature was 85℃, the time was 2 h, then washed with ethanol for 3 times, vacuum dried, the drying temperature was room temperature, the vacuum degree was 1.325 KPa, and the time was 3 h, to obtain an intermediate.

[0029] S2, in a five-necked flask equipped with a thermometer, a temperature sensing couple, a stirrer and a reflux condenser, glucose (0.03 mol, 5.4 g) was dissolved in 25 ml of water and heated to 35℃, 0.5 g of 40% NaOH solution was added, and the intermediate (0.01 mol, 3.84 g) was added in three times, 1.28 g each time, heated to reflux for 6 h, rotary evaporation under reduced pressure, the temperature was 70℃, the time was 30 min, and the rotation speed was 100 rmp, to obtain the antioxidant corrosion inhibitor.

[0030] Example 2 A preparation method of an antioxidant corrosion inhibitor, comprising the following steps: S1, in a five-port flask equipped with a thermometer, temperature sensing couple, stirrer, reflux condenser, thiourea (0.2 mol, 15.2 g) was dissolved in ethanol solvent 55 ml, heated to 60°C, after dissolution, while stirring, add trimesic acid (0.05 mol, 10.5 g), acetic acid (0.01 mol, 0.6 g), heated to reflux for 8 h; Distillation purification was carried out using a distillation device until no water and excess solvent was produced, the distillation temperature was 85°C, the time was 2h, then washed with ethanol for 3 times, vacuum dried, the drying temperature was room temperature, the vacuum degree was 1.325 KPa, the time was 3h, to obtain the intermediate.

[0031] S2, in a five-port flask equipped with a thermometer, temperature sensing couple, stirrer and reflux condenser, glucose (0.035 mol, 6.3 g) was dissolved in 30 ml water and heated to 35°C, 0.5 g of 40% NaOH solution was added, the intermediate (0.01 mol, 3.84 g) was added in three times, 1.28 g each time, heated to reflux for 8 h, rotary evaporation under reduced pressure, the temperature was 70°C, the time was 30 min, the rotation speed was 100 rpm, to obtain the antioxidant corrosion inhibitor.

[0032] Example 3 A method for preparing an antioxidant corrosion inhibitor, comprising the following steps: S1, in a five-port flask equipped with a thermometer, temperature sensing couple, stirrer, reflux condenser, thiourea (0.2 mol, 15.2 g) was dissolved in ethanol solvent 55 ml, heated to 50°C, after dissolution, while stirring, add trimesic acid (0.05 mol, 10.5 g), acetic acid (0.01 mol, 0.6 g), heated to reflux for 8 h; Distillation purification was carried out using a distillation device until no water and excess solvent was produced, the distillation temperature was 85°C, the time was 2h, then washed with ethanol for 3 times, vacuum dried, the drying temperature was room temperature, the vacuum degree was 1.325 KPa, the time was 3h, to obtain the intermediate.

[0033] S2, in a five-port flask equipped with a thermometer, temperature sensing couple, stirrer and reflux condenser, 0.035 mol glucose (0.035 mol, 6.3 g) was dissolved in 30 ml water and heated to 30°C, 0.5 g of 40% NaOH solution was added, the intermediate (0.01 mol, 3.84 g) was added in three times, 1.28 g each time, heated to reflux for 8 h, rotary evaporation under reduced pressure, the temperature was 70°C, the time was 30 min, the rotation speed was 100 rpm, to obtain the antioxidant corrosion inhibitor.

[0034] Comparative Example 1 A preparation method of an antioxidant corrosion inhibitor, comprising the following steps: S1, in a five-necked flask equipped with a thermometer, a temperature sensing couple, a stirrer, and a reflux condenser, thiourea (0.2 mol, 15.2 g) was dissolved in an ethanol solvent 55 ml, and heated to 60°C, after dissolution, uniform trimellitic acid (0.05 mol, 10.5 g) and acetic acid (0.01 mol, 0.6 g) were added while stirring, and heated to reflux for 8 h; distillation purification was performed using a distillation device until no water and excess solvent were produced, distillation purification was performed using a distillation device until no water and excess solvent were produced, the distillation temperature was 85°C, the time was 2h, then washed with ethanol for 3 times, vacuum dried, the drying temperature was room temperature, the vacuum degree was 1.325 KPa, and the time was 3h, to obtain an intermediate.

[0035] S2, in a five-necked flask equipped with a thermometer, a temperature sensing couple, a stirrer, and a reflux condenser, 4-aminobutyric acid (0.035 mol, 3.61 g) was dissolved in water (22 ml) and heated to 35°C, 0.5 g of a 40% NaOH solution was added, and the intermediate (0.01 mol, 3.84 g) was added in three portions, 1.28 g each time, heated to reflux for 8 h, and rotary evaporation under reduced pressure, at a temperature of 70°C, a time of 30 min, and a rotation speed range of 100 rmp, to obtain the antioxidant corrosion inhibitor.

[0036] The synthesis process of the antioxidant corrosion inhibitor in step S2 is as follows: .

[0037] Comparative Example 2 The antioxidant corrosion inhibitor was a commercially available antioxidant corrosion inhibitor R-M287 (Hubei Jingyu Material Co., Ltd.).

[0038] Comparative Example 3 The antioxidant corrosion inhibitor was an antioxidant corrosion inhibitor R-ZY183 (Hubei Jingyu Material Co., Ltd.).

[0039] Test Example 1: Determination of Water Solubility of Corrosion Inhibitor According to the standard "SYT 5273-2014 Performance Index and Evaluation Method of Corrosion Inhibitor for Oilfield Produced Water Treatment", the water solubility of the antioxidant corrosion inhibitors prepared in Examples 1-3 and Comparative Example 1 was determined, and the specific process was as follows: 10 mL of the corrosion inhibitor of Examples 1-3 and Comparative Example 1 was respectively dissolved in 90 mL of simulated formation water (simulated produced water was high salinity simulated formation water, and the ion concentration was as shown in Table 1), shaken, and placed in a water bath at 30°C for half an hour, and the dissolution was observed, and the results were shown in Table 2.

[0040] Table 1: Ion concentration of simulated formation water

[0041] Table 2: Water-solubility effect of corrosion inhibitor

[0042] From the above table, it can be seen that the water-solubility of the corrosion inhibitor prepared by the present application is better.

[0043] Test Example 2: Determination of corrosion inhibition performance of N80 carbon steel Using high salinity simulated formation water as the corrosion medium, under the conditions of 80℃ and 1% oxygen, N80 carbon steel was used to determine the corrosion inhibition performance of the corrosion inhibitors of Examples 1-3 and Comparative Examples 1-3 by 72h corrosion coupon test, and the corrosion inhibitor was added in an amount of 200ppm, and the results are shown in Table 3.

[0044] Table 3: Determination results of corrosion inhibition performance of N80 carbon steel

[0045] Test Example 3: Determination of corrosion inhibition performance of A3 carbon steel Using high salinity simulated formation water as the corrosion medium, under the conditions of 80℃ and 1% oxygen, A3 carbon steel was used to determine the corrosion inhibition performance of the corrosion inhibitors of Examples 1-3 and Comparative Examples 1-3 by 72h corrosion coupon test, and the corrosion inhibitor was added in an amount of 200ppm, and the results are shown in Table 4.

[0046] Table 4: Determination results of corrosion inhibition performance of A3 carbon steel

[0047] From the water-solubility effect and the slow-release performance, the antioxidant corrosion inhibitor of Comparative Example 1 obtained by modifying the intermediate with straight-chain acid 4-aminobutyric acid has obvious improvement in effect compared with Comparative Examples 2 and 3, but the antioxidant corrosion inhibitor obtained by modifying the intermediate with the cyclic structure of glucose has better effect.

[0048] In summary, the antioxidant corrosion inhibitor of the present application has the advantages of not being easy to decompose at high temperature, strong adsorption, good solubility and dispersibility in high salinity simulated formation water, and can better inhibit the oxygen corrosion of N80 and A3 carbon steel in high temperature and high salinity simulated formation water, so the antioxidant corrosion inhibitor can effectively solve the problem of oxygen corrosion of oil wells.

[0049] Finally, it should be noted that: the above description is only the preferred embodiments of the present application, and is not used to limit the present application, although the present application has been described in detail with reference to the foregoing embodiments, for those skilled in the art, the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced by equivalents, any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An antioxidant corrosion inhibitor, characterized in that, Having a structure as formula (I): （Ⅰ）。 2. The method of claim 1, wherein the antioxidant corrosion inhibitor is prepared by the steps of: a) mixing the antioxidant and the corrosion inhibitor; b) adding the antioxidant corrosion inhibitor to the base oil; and c) mixing the antioxidant corrosion inhibitor with the base oil. Comprising the following steps: Dissolve thiourea in alcohol organic solvent, heated to 40-60℃, add trimesic acid, catalyst, heated to reflux, purified by distillation, washing, vacuum drying, to get intermediate; Dissolve glucose in water and heated to 30-35℃, add sodium hydroxide, intermediate, heated to reflux reaction, rotary evaporation under reduced pressure.

3. The method for preparing an antioxidant corrosion inhibitor according to claim 2, wherein: The molar ratio of thiourea, trimesic acid, catalyst is (3-4):1:0.

2.

4. The method for preparing an antioxidant corrosion inhibitor according to claim 2, wherein: The alcohol organic solvent is 2-3 times of the mass of the reaction raw material, and the reaction raw material is thiourea and trimesic acid.

5. The method for preparing an antioxidant corrosion inhibitor according to claim 2, wherein: The alcohol organic solvent is any one of ethanol and methanol.

6. The method for preparing an antioxidant corrosion inhibitor according to claim 2, wherein: The catalyst is any one of acetic acid and formic acid.

7. The method for preparing an antioxidant corrosion inhibitor according to claim 2, wherein: The synthesis process of the intermediate is: 。 8. The method for preparing an antioxidant corrosion inhibitor according to claim 2, wherein: The molar ratio of glucose, sodium hydroxide, intermediate is (3-4):0.5:

1.

9. The method for preparing an antioxidant corrosion inhibitor according to claim 2, wherein: The synthesis process of the anti-oxidation corrosion inhibitor is: 。 10. The use of an antioxidant corrosion inhibitor according to claim 1, wherein The application is oilfield produced water treatment.

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