Efficient composite corrosion inhibitor for oil and gas fields as well as preparation method and application of efficient composite corrosion inhibitor

Abstract

The invention belongs to the technical field of oil field chemical agent preparation, and discloses an efficient composite corrosion inhibitor for oil and gas fields and a preparation method and application thereof, the composite corrosion inhibitor is prepared from the following main components: 8-20 parts of amido gemini quaternary ammonium salt and 6-30 parts of corrosion inhibition synergist; the corrosion inhibition synergist is prepared from the following components in parts by weight: 12 to 18 parts of polyepoxysuccinic acid, 3 to 7 parts of ethylene diamine tetra (methylene phosphonic acid) sodium, 5 to 14 parts of 2-phosphonobutane-1, 2, 4-trihydroxy acid and 2 to 6 parts of sulfurized semicarbazide; and 15-30 parts of a solvent ethanol, wherein the solvent is ethanol with the mass fraction of 80%. The corrosion inhibitor prepared in the invention has the advantages of small influence on environment, low cost, good corrosion inhibition effect, wide application range, simple preparation method, no need of too high temperature and high pressure, suitableness for industrial large-scale popularization and production, and capability of satisfying most on-site operation requirements.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparation of oilfield chemicals, and relates to a high-efficiency composite corrosion inhibitor for oil and gas fields, a preparation method thereof, and an application thereof. Background Art

[0002] The corrosion of metal materials has always accompanied the entire production process of oil and gas fields and gas storage reservoirs. The commonly used internal anti-corrosion technologies for pipelines mainly include internal anti-corrosion coatings and injection of corrosion inhibitors. However, even if the pipeline has an anti-corrosion coating, it is generally applied before construction at the initial stage of the construction of oil and gas fields and gas storage reservoirs. With the continuous production and operation of oil and gas fields and gas storage reservoirs, the anti-corrosion coating is prone to damage in the long-term "humid" environment. After the coating is damaged, it will not only fail to play a protective role, but will instead exacerbate the corrosion of the metal. Injection of corrosion inhibitors can be carried out at any time.

[0003] At present, there are many types of corrosion inhibitors, which are widely used in oil and gas fields and gas storage reservoirs. However, due to differences in different production conditions and operating conditions, it is difficult to find a corrosion inhibitor that is suitable for the production conditions of various oil and gas fields and gas storage reservoirs. Therefore, it is necessary to develop a corrosion inhibitor formulation to meet this demand.

[0004] In the actual operation of oil and gas field development or gas storage reservoir surface engineering, the operating conditions are not constant. The existing corrosion inhibitors have poor applicability. After changes in equipment operating parameters, environmental temperature, etc., the corrosion inhibition effect of the corrosion inhibitor may be greatly reduced, often resulting in only an increase in the dosage of the corrosion inhibitor at the site, but the corrosion inhibition effect is not optimistic. Summary of the Invention

[0005] In order to overcome the deficiencies of the prior art, the present invention develops a high-efficiency and widely applicable composite corrosion inhibitor for seasonal and periodic changes in operating conditions. It has stable performance, good corrosion inhibition effect, and low injection volume, so as to reduce on-site investment and maintenance costs and increase corporate profits.

[0006] The present invention relates to a high-efficiency composite corrosion inhibitor for oil and gas fields, a preparation method thereof, and an application thereof. The prepared corrosion inhibitor has less impact on the environment, a simple preparation method, low cost, good corrosion inhibition effect, and a wide application range, and is suitable for large-scale industrial promotion and production.

[0007] A high-efficiency composite corrosion inhibitor for oil and gas fields includes amide-based gemini quaternary ammonium salts, corrosion inhibition synergists, and solvent ethanol.

[0008] Further, by mass, 8-20 parts of amide-based gemini quaternary ammonium salts, 6-30 parts of corrosion inhibition synergists, and 15-30 parts of solvent ethanol.

[0009] Further, the corrosion inhibition synergists include polyepoxysuccinic acid, sodium ethylene diamine tetra(methylene phosphonate), 2-phosphonobutane-1,2,4-tricarboxylic acid, and thiosemicarbazide.

[0010] Furthermore, by mass, the corrosion inhibitor synergist includes 12-18 parts of polyepoxysuccinic acid, 3-7 parts of ethylenediaminetetra(methylene phosphonic acid) sodium salt, 5-14 parts of 2-phosphonobutane-1,2,4-tricarboxylic acid, and 2-6 parts of semicarbazide sulfide.

[0011] Furthermore, the solvent ethanol is ethanol with a mass fraction of 80%.

[0012] Among them, the amido gemini quaternary ammonium salt is used as the main component, and polyepoxysuccinic acid, ethylenediaminetetra(methylene phosphonic acid) sodium salt, 2-phosphonobutane-1,2,4-tricarboxylic acid, and semicarbazide sulfide are used as corrosion inhibitor synergists.

[0013] A preparation method of a high-efficiency composite corrosion inhibitor for oil and gas fields, and the preparation temperature is 20-35°C.

[0014] The specific preparation method is as follows: After adding the amido gemini quaternary ammonium salt at 25°C, the temperature is raised to 35°C, then polyepoxysuccinic acid and semicarbazide sulfide are added, and then the temperature is lowered to 20°C, and ethylenediaminetetra(methylene phosphonic acid) sodium salt and 2-phosphonobutane-1,2,4-tricarboxylic acid are added.

[0015] An application of a high-efficiency composite corrosion inhibitor for oil and gas fields, and the use temperature is 10-35°C.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] After verification, the corrosion inhibitor prepared by the present invention has less impact on the environment, low cost, good corrosion inhibition effect, wide application range, simple preparation method, does not require too high temperature and high pressure, is suitable for large-scale industrial promotion and production, and can meet the operation requirements of most sites. Description of the Drawings

[0018] Figure 1 It is the polarization curve diagram of L360Q steel in the corrosion solution without adding the corrosion inhibitor and in the corrosion solutions after adding the corrosion inhibitor with an effective concentration of 100 ppm according to Examples 2, 3, 4, and 5 in Example 3;

[0019] Figure 2 It is the impedance spectrum diagram of L360Q steel in the corrosion solution of the corrosion inhibitor and in the corrosion solutions after adding the corrosion inhibitor with an effective concentration of 100 ppm according to Examples 2, 3, 4, and 5 in Example 3;

[0020] Figure 3 (a), (b), (c), (d), (e) are the corrosion morphologies of L360Q steel in Example 3 after 48 hours of dynamic weight loss in the corrosion solution without adding the corrosion inhibitor and in the corrosion solutions after adding the corrosion inhibitor with an effective concentration of 100 ppm according to Examples 2, 3, 4, and 5 (b). Specific Embodiments

[0021] The present invention will be described in detail below through specific embodiments, but the protection scope of the present invention is not limited. Unless otherwise specified, the experimental methods used in the present invention are all conventional methods, and the experimental equipment, materials, reagents, etc. used can all be obtained from commercial channels.

[0022] Example 1

[0023] A high-efficiency composite corrosion inhibitor for oil and gas fields and its preparation method. The required corrosion inhibitor raw materials include:

[0024] Amido gemini quaternary ammonium salt, polyepoxysuccinic acid, ethylenediamine tetramethylene phosphonic acid sodium salt, 2-phosphonobutane-1,2,3-tricarboxylic acid semicarbazide.

[0025] A high-efficiency composite corrosion inhibitor for oil and gas fields and its preparation method. The components of the required corrosion inhibitor raw materials are calculated by mass fraction: 14 parts of amido gemini quaternary ammonium salt, 18 parts of corrosion inhibitor synergist; and the corrosion inhibitor synergist components are 15 parts of polyepoxysuccinic acid, 5 parts of ethylenediamine tetramethylene phosphonic acid sodium salt, 10 parts of 2-phosphonobutane-1,2,4-tricarboxylic acid, 4 parts of semicarbazide sulfide; 23 parts of solvent ethanol; the raw material of the required solvent is ethanol with a mass fraction of 80%. A high-efficiency composite corrosion inhibitor for oil and gas fields and its preparation method. Specifically, after adding amido gemini quaternary ammonium salt at 25°C, the temperature is raised to 35°C, then polyepoxysuccinic acid and semicarbazide sulfide are added, and then the temperature is lowered to 20°C to add ethylenediamine tetramethylene phosphonic acid sodium salt and 2-phosphonobutane-1,2,4-tricarboxylic acid. The required temperature for its preparation is 20 - 35°C, and its applicable temperature is 10 - 35°C.

[0026] In the examples, the corrosion inhibitor prepared by the present invention was added to the on-site produced water for simulation experiments, and the on-site produced water without adding the corrosion inhibitor alone was used as a blank control.

[0027] Example 2

[0028] This example is based on Example 1, and the reaction temperature is selected as 20°C, and the other conditions remain unchanged.

[0029] Example 3

[0030] This example is based on Example 1, and the reaction temperature is selected as 25°C, and the other conditions remain unchanged.

[0031] Example 4

[0032] This example is based on Example 1, and the reaction temperature is selected as 30°C, and the other conditions remain unchanged.

[0033] Example 5

[0034] This example is based on Example 1, and the reaction temperature is selected as 35°C, and the other conditions remain unchanged.

[0035] Example 6 Performance Evaluation Test of Corrosion Inhibitor

[0036] For the electrochemical test, a CS350 electrochemical workstation (Wuhan KOST Instrument Co., Ltd.) was used to conduct electrochemical polarization and electrochemical impedance analysis on L360Q steel. Table 1 shows the simulated corrosion solution.

[0037] Electrochemical test:

[0038] The L360Q steel was processed into a square metal block with dimensions of 10 mm×10 mm×3 mm. The surface was polished smoothly with 180#, 320#, 600#, 800#, 1000# and 1500# sandpapers in sequence and then solidified and sealed with epoxy resin for standby. The traditional three - electrode system was adopted for the electrochemical experiment. The working electrode was made of L360Q steel, the reference electrode was a saturated calomel electrode, and the auxiliary electrode was a platinum metal electrode. The concentration of the corrosion inhibitor was expressed as the volume ratio between the corrosion inhibitor and the corrosion solution, and the corrosion inhibitor concentration was selected as 100 ppm.

[0039] When testing the polarization curve, the scanning potential range was set to ±200 mV relative to the open - circuit potential, and the potentiodynamic scanning rate was set to 0.166 mV / s. Then, the required relevant parameters were obtained by fitting through the Tafel extrapolation method. The corrosion inhibition efficiency (η) was obtained from the following formula:

[0040]

[0041] In the formula, η is the corrosion inhibition efficiency, %; and I corr are the corrosion current densities before and after adding the corrosion inhibitor, respectively, μA / cm 2 .

[0042] Figure 1 are the electrochemical polarization diagrams of L360Q steel in the corrosion solution without adding the corrosion inhibitor and in the corrosion solutions with the corrosion inhibitor added according to the components in Example 2, Example 3, Example 4 and Example 5. Table 2 shows the results of the polarization experiment. It can be seen from the figure that after adding the corrosion inhibitor, the corrosion potential shifts positively, and both the cathode part and the anode part of the curve move towards the lower potential, indicating that the reactions at both the anode and cathode are controlled and the corrosion rate decreases.

[0043] Figure 2 is the electrochemical impedance spectrum of L360Q steel in the corrosion solution with a corrosion inhibitor concentration of 100 ppm. By observing the electrochemical impedance spectra of Example 2, Example 3, Example 4 and Example 5, it can be seen that as the component of the corrosion inhibitor increases, the radius of the capacitive reactance arc in the high - frequency region gradually becomes larger, indicating that as the concentration of the corrosion inhibitor increases, the protective layer formed by the adsorption of the corrosion inhibitor molecules on the surface of L360Q steel becomes more complete. Among them, Table 3 shows the EIS parameters fitted by using the equivalent circuit diagram. The formula is:

[0044]

[0045] Where η is the corrosion inhibition efficiency, %; R ct are the charge transfer resistances before and after adding the corrosion inhibitor, respectively, in Ω·cm 2 .

[0046] Observation of surface morphology: The size of the L360Q steel sample for morphology observation is 50mm×10mm×3mm. After being polished to a bright surface, it is dynamically corroded in the corrosion solution without adding the corrosion inhibitor for 48 hours. After taking it out and drying, its corrosion morphology is observed by a scanning electron microscope; then four groups of dynamic corrosion experiments are carried out according to the components in Example 2, Example 3, Example 4 and Example 5. After taking it out and drying, its corrosion morphology is observed by an electron microscope.

[0047] Furthermore, the calculation formula for the corrosion rate in the weight loss experiment is as follows:

[0048]

[0049] Where: C R ——corrosion rate, mm / a; m0——weight loss of the blank sample of the same acid-pickled material, g; m1——mass of the sample before the experiment, g; m2——mass of the sample after removing the corrosion products, g; S——surface area of the sample exposed to the corrosion environment, m 2 ; Δt——experimental time, h; D——density of the material, kg / m 3 . (The density of L360Q steel is calculated as 7850 kg / m 3 ) Furthermore, the calculation formula for the corrosion inhibition efficiency is:

[0050]

[0051] Where are the corrosion rates of L360Q steel before and after adding the corrosion inhibitor, respectively, in mm / a.

[0052] Figure 3 (a), Figure 3 (b), Figure 3 (c), Figure 3 (d), Figure 3 (e) are the appearance morphologies of the steel sheet after being corroded in the corrosion solution without adding the corrosion inhibitor and the corrosion solution after adding the corrosion inhibitor according to the components in Example 2, Example 3, Example 4 and Example 5 for 48 hours. After weight loss calculation, the corrosion inhibition rates can be seen in Table 4.

[0053] Table 1 Corrosion solution formulation table

[0054] Ion <![CDATA[Cl - > <![CDATA[NO3 - > <![CDATA[Ca 2+ > <![CDATA[K + > <![CDATA[Mg 2+ > <![CDATA[Na + > <![CDATA[CO3 2- > <![CDATA[HCO3 - > Concentration (mg / L) 2517.70 29.89 14.01 65.96 8.91 3571.46 1156.75 3721.21

[0055] Table 2 Results of Polarization Experiment

[0056]

[0057] Table 3 Fitting Results of Electrochemical Impedance Spectroscopy

[0058]

[0059] Table 4 Performance Test Results of a High-Efficiency Composite Corrosion Inhibitor for Oil and Gas Fields

[0060] Example Reagent Concentration (ppm) Corrosion Inhibition Rate (%) Example 2 100 82.84％ Example 3 100 86.98％ Example 4 100 94.87％ Example 5 100 96.31％

[0061] The above-described embodiments are only the preferred embodiments of the present invention, rather than all the feasible embodiments of the present invention. Any obvious changes made by those of ordinary skill in the art without departing from the principles and spirit of the present invention should be considered to be included within the scope of the claims of the present invention.

Claims

1. An efficient composite corrosion inhibitor for oil and gas fields, characterized in that, It includes amide-based gemini quaternary ammonium salt, corrosion inhibitor synergist and solvent ethanol.

2. The efficient composite corrosion inhibitor for oil and gas fields according to claim 1, characterized in that, By mass, 8-20 parts of amide-based gemini quaternary ammonium salt, 6-30 parts of corrosion inhibitor synergist, and 15-30 parts of solvent ethanol.

3. The efficient composite corrosion inhibitor for oil and gas fields according to claim 1, characterized in that, The corrosion inhibitor synergist includes polyepoxysuccinic acid, sodium ethylene diamine tetra(methylene phosphonate), 2-phosphonobutane-1,2,4-tricarboxylic acid and semicarbazide sulfide.

4. The efficient composite corrosion inhibitor for oil and gas fields according to claim 3, characterized in that, By mass, the corrosion inhibitor synergist includes 12-18 parts of polyepoxysuccinic acid, 3-7 parts of sodium ethylene diamine tetra(methylene phosphonate), 5-14 parts of 2-phosphonobutane-1,2,4-tricarboxylic acid, and 2-6 parts of semicarbazide sulfide.

5. The efficient composite corrosion inhibitor for oil and gas fields according to claim 1, characterized in that, The solvent ethanol is ethanol with a mass fraction of 80%.

6. A preparation method of an efficient composite corrosion inhibitor for oil and gas fields, characterized in that, The preparation temperature is 20-35°C.

7. The preparation method of the efficient composite corrosion inhibitor for oil and gas fields according to claim 1, characterized in that, The specific preparation method is: add amide-based gemini quaternary ammonium salt at 25°C, then raise the temperature to 35°C, then add polyepoxysuccinic acid and semicarbazide sulfide, and then lower the temperature to 20°C, and add sodium ethylene diamine tetra(methylene phosphonate) and 2-phosphonobutane-1,2,4-tricarboxylic acid.

8. An application of an efficient composite corrosion inhibitor for oil and gas fields, characterized in that, The use temperature is 10-35°C.

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