An antioxidant corrosion inhibitor for oil wells and a preparation method thereof

Abstract

The application relates to an antioxidant corrosion inhibitor for oil wells and a preparation method thereof, and belongs to the technical field of petroleum chemical 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 to reflux for 6-8 hours, and performing distillation purification, washing and vacuum drying to obtain an intermediate; dissolving glucose in water and heating to 30-35 DEG C, adding sodium hydroxide and the intermediate, heating to reflux for reaction for 6-8 hours, and performing rotary evaporation under reduced pressure to obtain the antioxidant corrosion inhibitor. The antioxidant corrosion inhibitor has the advantages of not being easy to decompose under high temperature, strong adsorption, good dissolving dispersity in high salinity 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 solubility 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):

[0007] (I).

[0008] In a second aspect, the present application provides a preparation method of the oxygen-resistant corrosion inhibitor, comprising the following steps:

[0009] S1, dissolve thiourea in an alcohol organic solvent, heat to 40-60℃, add trimesic acid, acid catalyst, heat to reflux for 6-8h, and then purify by distillation, wash, and vacuum dry to obtain an intermediate;

[0010] S2, dissolve glucose in water and heat to 30-35℃, 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.

[0011] Further, the molar ratio of the thiourea, trimesic acid and catalyst in step S1 is (3-4):1:0.2.

[0012] Further, the alcohol organic solvent in step S1 is 2-3 times the mass of the reaction raw materials, and the reaction raw materials are thiourea and trimesic acid.

[0013] Further, the alcohol organic solvent in step S1 is any one of ethanol and methanol.

[0014] Further, the catalyst in step S1 is any one of acetic acid and formic acid.

[0015] Further, the distillation purification condition in step S1 is that the distillation temperature is 80-90℃ and the time is 1-3h.

[0016] Preferably, the distillation purification condition is that the distillation temperature is 85℃ and the time is 2h.

[0017] Further, the washing in step S1 is cleaning 2-5 times with a detergent; and the detergent is ethanol or methanol.

[0018] Further, the vacuum drying condition in step S1 is that the drying temperature is room temperature, the vacuum degree is 1-2KPa, and the time is 2-4h.

[0019] 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.

[0020] Further, the synthesis process of the intermediate in step S1 is as follows:

[0021] .

[0022] Further, the molar ratio of glucose, sodium hydroxide and the intermediate in step S2 is (3-4):0.5:1.

[0023] Further, the conditions of the reduced pressure rotary evaporation in step S2 are as follows: the temperature is 60-80℃, the reduced pressure rotary evaporation concentration time is 15-45min, and the rotation speed range is 80-150rmp.

[0024] Preferably, the conditions of the reduced pressure rotary evaporation are as follows: the temperature is 70℃, the reduced pressure rotary evaporation concentration time is 30min, and the rotation speed range is 100rmp.

[0025] Further, the synthesis process of the anti-oxidation corrosion inhibitor in step S2 is as follows:

[0026] .

[0027] In a third aspect, the present application provides an application of the anti-oxidation corrosion inhibitor in oil well exploitation.

[0028] Compared with the prior art, the present application has the following beneficial effects:

[0029] (1) The anti-oxidation corrosion inhibitor of the present application is composed of the polar group with N, S and other atoms with large electronegativity as the center and the non-polar group composed of C and H atoms, and belongs to the adsorption type corrosion inhibitor, which can quickly adsorb on the metal surface to form an oxidation film and show excellent corrosion inhibition effect.

[0030] (2) The anti-oxidation corrosion inhibitor of the present application forms multiple adsorption centers on the surface of the 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, 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 certain direction to form a hydrophobic film, thereby hindering the corrosion reaction of the carbon steel matrix. In addition, the C=S double bond and -OH have reducing property, which can also consume dissolved oxygen in water, thereby enhancing the anti-oxidation effect.

[0031] (3) The anti-oxidation corrosion inhibitor of the present 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-oxidation corrosion inhibitor can effectively solve the problem of oxygen corrosion of oil wells.

[0032] Other features and advantages of the present application will be set forth in the following specification, and in part will become apparent to those skilled in the art upon examination of the following specification or can be learned by practice of the application. The objects and other advantages of the application can be realized and attained by the specific embodiments particularly pointed out in the written description. DETAILED DESCRIPTION

[0033] 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 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.

[0034] Example 1

[0035] A preparation method of an antioxidant corrosion inhibitor, comprising the following steps:

[0036] 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;

[0037] Distillation purification was carried out using a distillation device until no water and excess solvent were 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.

[0038] 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.

[0039] Example 2

[0040] A preparation method of an antioxidant corrosion inhibitor, comprising the following steps:

[0041] 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;

[0042] 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.

[0043] 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 range was 100 rmp, to obtain the antioxidant corrosion inhibitor.

[0044] Example 3

[0045] A method for preparing an antioxidant corrosion inhibitor, comprising the following steps:

[0046] 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;

[0047] 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.

[0048] S2, in a five-port flask equipped with a thermometer, temperature sensing couple, stirrer and reflux condenser, 0.035 mol of glucose (0.035 mol, 6.3 g) was dissolved in 30 ml of water and warmed to 30°C, 0.5 g of 40% NaOH solution was added, the intermediate (0.01 mol, 3.84 g) was added in three portions, 1.28 g each time, and heated to reflux for 8 h, rotary evaporation was performed under reduced pressure, the temperature was 70°C, the time was 30 min, and the rotation speed was 100 rpm, to obtain the antioxidant corrosion inhibitor.

[0049] Comparative Example 1

[0050] A method for preparing an antioxidant corrosion inhibitor, comprising the following steps:

[0051] 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 55 ml of ethanol solvent, warmed to 60°C, after heating and dissolving, benzene-1, 3, 5-tricarboxylic acid (0.05 mol, 10.5 g) and acetic acid (0.01 mol, 0.6 g) were added while stirring;

[0052] 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 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 the intermediate.

[0053] S2, in a five-port flask equipped with a thermometer, temperature sensing couple, stirrer and reflux condenser, 4-aminobutyric acid (0.035 mol, 3.61 g) was dissolved in water (22 ml) and warmed to 35°C, 0.5 g of 40% NaOH solution was added, the intermediate (0.01 mol, 3.84 g) was added in three portions, 1.28 g each time, and heated to reflux for 8 h, rotary evaporation was performed under reduced pressure, the temperature was 70°C, the time was 30 min, and the rotation speed was 100 rpm, to obtain the antioxidant corrosion inhibitor.

[0054] The synthesis process of the antioxidant corrosion inhibitor of step S2 is as follows:

[0055] .

[0056] Comparative Example 2

[0057] The antioxidant corrosion inhibitor was a commercially available antioxidant corrosion inhibitor R-M287 (Hubei Jingyu Material Co., Ltd.).

[0058] Comparative Example 3

[0059] The antioxidant corrosion inhibitor is antioxidant corrosion inhibitor R-ZY183 (Hubei Jingyu Material Co., Ltd.).

[0060] Test Example 1: Water solubility determination of corrosion inhibitor

[0061] 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. The specific process is 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 is high salinity simulated formation water, and the ion concentration is as shown in Table 1), shaken, and placed in a water bath at 30℃ for half an hour, and the dissolution was observed. The results are shown in Table 2.

[0062] Table 1: Ion concentration of simulated formation water

[0063]

[0064] Table 2: Water solubility effect of corrosion inhibitor

[0065]

[0066] From the above table, it can be seen that the water solubility of the corrosion inhibitor prepared in the present application is better.

[0067] Test Example 2: N80 carbon steel corrosion performance determination

[0068] With high salinity simulated formation water as the corrosion medium, under the conditions of 80℃ and 1% oxygen, N80 carbon steel was used, and the corrosion performance of the corrosion inhibitors of Examples 1-3 and Comparative Examples 1-3 was determined by 72h corrosion coupon experiment, and the corrosion inhibitor was added in an amount of 200ppm. The results are shown in Table 3.

[0069] Table 3: N80 carbon steel corrosion performance determination results

[0070]

[0071] Test Example 3: A3 carbon steel corrosion performance determination

[0072] With high salinity simulated formation water as the corrosion medium, under the conditions of 80℃ and 1% oxygen, A3 carbon steel was used, and the corrosion performance of the corrosion inhibitors of Examples 1-3 and Comparative Examples 1-3 was determined by 72h corrosion coupon experiment, and the corrosion inhibitor was added in an amount of 200ppm. The results are shown in Table 4.

[0073] Table 4: A3 carbon steel corrosion performance determination results

[0074]

[0075] From the water-solubility effect and the slow-release performance, the antioxidant corrosion inhibitor of the comparative example 1 obtained by using the straight-chain acid 4-aminobutyric acid to modify the intermediate has obvious effect promotion compared with the comparative example 2 and the comparative example 3, but the antioxidant corrosion inhibitor obtained by using the glucose cyclic structure to modify the intermediate has better effect.

[0076] In conclusion, the antioxidant corrosion inhibitor has the advantages of not being easy to decompose at high temperature, strong adsorption, good dissolving dispersibility in high salinity simulated formation water and the like, and can better inhibit the oxygen corrosion of N80 and A3 carbon steels in high temperature and high salinity simulated formation water, so that the antioxidant corrosion inhibitor can effectively solve the oxygen corrosion problem of oil wells.

[0077] Finally, it should be noted that: the above only for the preferred embodiments of the present application, and not for limiting the present application, although the foregoing embodiments of the present application are described in detail, for those skilled in the art, it still can be modified, or part of the technical features of the equivalent replacement, within the spirit and principles of the present application, any modification, equivalent replacement, improvement, etc., should 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. A process for the preparation of an antioxidant corrosion inhibitor as claimed in claim 1, wherein, It comprises the following steps: Sulfourea is dissolved in an alcohol organic solvent, and heated to 40-60℃, and then trimesic acid and a catalyst are added and heated to reflux, and then purified by distillation, washed, and vacuum dried to obtain an intermediate; Glucose is dissolved in water and heated to 30-35℃, and then sodium hydroxide and the intermediate are added and heated to reflux to react, and then rotary evaporation is performed under reduced pressure to obtain the antioxidant corrosion inhibitor; The synthesis process of the intermediate is as follows: ； The synthesis process of the antioxidant corrosion inhibitor is as follows: 。 3. The method for preparing an antioxidant corrosion inhibitor according to claim 2, characterized in that, The molar ratio of the sulfourea, trimesic acid, and catalyst is (3-4):1:0.

2.

4. The method for preparing an antioxidant corrosion inhibitor according to claim 2, characterized in that, The alcohol organic solvent is 2-3 times the mass of the reaction raw materials, and the reaction raw materials are sulfourea and trimesic acid.

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

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

7. The method for preparing an antioxidant corrosion inhibitor according to claim 2, characterized in that, The molar ratio of the glucose, sodium hydroxide, and intermediate is (3-4):0.5:

1.

8. Application of the antioxidant corrosion inhibitor as claimed in claim 1 to treatment of oilfield produced water.

Images