High-density temperature-resistant corrosion inhibitor for oil extraction pump and preparation method thereof

Abstract

The invention relates to the technical field of corrosion inhibitors and metal corrosion prevention, and discloses a high-density temperature-resistant corrosion inhibitor for an oil extraction pump and a preparation method thereof.The corrosion inhibitor is composed of sodium benzenesulfonate 180.00-200.00 g / L, sodium molybdate 10.00-15.00 g / L and sodium silicate 0.10-0.20 g / L. deionized water serves as a solvent, the density of the corrosion inhibitor is larger than 1.150 g / mL, and the high-density temperature-resistant corrosion inhibitor has excellent corrosion inhibition performance on 45 # carbon steel and 316 L stainless steel in the high-pressure water environment at the temperature of 120-180 DEG C; and the room-temperature corrosion inhibition efficiency is not lower than 85.00%. The corrosion inhibitor is a compound corrosion inhibitor, a compact corrosion-resistant film is formed through the synergistic effect of components, and the corrosion inhibitor is environmentally friendly, low in cost, easy to prepare and capable of accurately adapting to the extreme working condition of direct electric heating auxiliary exploitation of thick oil, effectively solves the corrosion problem of an oil extraction pump protector cavity, prolongs the service life of equipment and has wide application prospects and huge economic benefits.

Description

High-density, high-temperature corrosion inhibitor for oil pumps and its preparation method Technical Field

[0001] This invention relates to the field of corrosion inhibitor technology and metal corrosion protection, and in particular provides a high-density, high-temperature resistant corrosion inhibitor for oil pumps and its preparation method, which is especially suitable for corrosion protection of oil pumps in the direct electric heating assisted extraction process of viscous oil. Background Technology

[0002] As global oil and gas exploration and development extends to deeper heavy oil blocks, heavy oil extraction technologies are constantly being upgraded. Compared to traditional high-energy-consuming steam-heated extraction technologies, direct electric heating assisted extraction technology, with its advantages of energy saving, high efficiency, and compact equipment, has become a new direction for the development of low-yield, low-permeability, and inefficient heavy oil resources. This technology can achieve simultaneous heating and extraction, with the well temperature typically maintained at around 150℃, and not exceeding 180℃. However, it also involves harsh environments such as high pressure and high salinity, posing a severe challenge to the corrosion protection of oil extraction equipment.

[0003] As the core power equipment for oil extraction, the stable operation of the oil production pump directly determines the production efficiency and economic benefits of the oil and gas field. The oil production pump protector is a key component ensuring the long-term reliable operation of the pump. Internally, it features a sealed cavity welded from 45# carbon steel and 316L stainless steel sheets. This cavity can freely expand and contract with changes in oil pressure within the pump and is connected to the completion fluid or oil outside the protector via a dedicated valve, playing a crucial role in balancing pressure and isolating impurities. However, in actual production, the high concentration of chloride ions accumulated in the completion fluid and oil can penetrate the protector cavity through valve gaps or minor leaks. Under the combined effects of high temperature (120-180℃) and high pressure, this causes severe corrosion to the metal surface of the cavity, leading to pitting corrosion, crevice corrosion, and other localized corrosion. In severe cases, this can cause the cavity to rupture, resulting in pump shutdown, oil and gas leaks, and other safety accidents, significantly shortening equipment lifespan and causing huge economic losses.

[0004] Completion fluid, as a key working fluid in the oil and gas field completion process, plays an important role in pressure regulation and reservoir protection. Its density is typically in the range of 1.050-1.120 g / mL, and it is rich in corrosive media such as chloride ions. Chloride ions not only accelerate the anodic dissolution of steel materials and lower the metal corrosion potential, but they can also penetrate the passivation film on the metal surface to form pitting corrosion nuclei, exacerbating the corrosion process of the oil pump protector cavity. Meanwhile, the density of petroleum itself is usually less than 1.000 g / mL, which, together with the completion fluid, constitutes the external corrosive environment of the oil pump protector, further increasing the risk of cavity corrosion.

[0005] To address the corrosion problem of oil pump protectors, corrosion inhibitors have become an economical and effective protective measure in industrial applications. Commonly used corrosion inhibitors can be classified into four types based on their mechanism of action: anodic-oxidation film type, cathodic-precipitation film type, adsorption type, and composite type. However, existing products all have significant shortcomings under the specific operating conditions of heavy oil electrothermal extraction: traditional adsorption corrosion inhibitors have poor adsorption film stability and are prone to desorption and failure at high temperatures of 120-180℃; cathodic-precipitation film type corrosion inhibitors form porous films with weak adhesion to metal surfaces, resulting in limited corrosion inhibition efficiency; insufficient dosage of a single anodic corrosion inhibitor can easily lead to pitting corrosion, and some products containing chromates and other components are highly toxic and do not meet environmental protection requirements. While composite corrosion inhibitors can adapt to complex scenarios through synergistic effects of their components, products that meet the requirements of "density higher than completion fluid and oil, and long-term stable residence in the protector cavity" for the 120-180℃ temperature range of direct electrothermal assisted extraction of heavy oil are still relatively scarce.

[0006] Furthermore, the density characteristics of the corrosion inhibitor are crucial to ensuring the protective effect: if the density of the corrosion inhibitor is lower than that of the completion fluid or oil, it will easily flow out of the protector cavity and fail to form continuous protection; only when the density of the corrosion inhibitor is greater than 1.150 g / mL (higher than the density of the completion fluid and oil) can it stably remain inside the cavity and exert a long-term corrosion inhibition effect. Therefore, developing a high-density, high-temperature-resistant (120-180℃), highly efficient, environmentally friendly, and easy-to-prepare compound corrosion inhibitor for corrosion protection of the oil pump protector cavity is of great practical significance for promoting the large-scale application of heavy oil direct electric heating assisted extraction technology and ensuring stable production in oil and gas fields. Summary of the Invention

[0007] Therefore, the purpose of this invention is to provide a high-density, temperature-resistant corrosion inhibitor for oil pumps and its preparation method, aiming to prepare a compound corrosion inhibitor with corrosion inhibition function, high efficiency and stability, and environmental friendliness, which can be stable for a long time in the scenario of direct electric heating assisted extraction of heavy oil.

[0008] This invention provides a high-density, temperature-resistant corrosion inhibitor for oil pumps, comprising: sodium benzenesulfonate, sodium molybdate, sodium silicate, and deionized water, wherein the concentration of sodium benzenesulfonate is 180.00-200.00 g / L, the concentration of sodium molybdate is 10.00-15.00 g / L, the concentration of sodium silicate is 0.10-0.20 g / L, and the density of the corrosion inhibitor is greater than 1.150 g / mL.

[0009] This invention also provides a method for preparing the above-mentioned high-density, high-temperature corrosion inhibitor for oil pumps, comprising:

[0010] Raw material preparation: Select analytical grade sodium benzenesulfonate, sodium molybdate, sodium silicate reagents, and deionized water;

[0011] Mass calculation: Calculate the required mass of each reagent based on the target preparation volume and the concentration of each component;

[0012] Separate dissolution: Weigh each reagent according to the required mass and place each reagent in a beaker separately. Add an appropriate amount of deionized water and stir until completely dissolved to avoid premature reaction between components.

[0013] Mixing and adjusting to volume: Pour the separately dissolved sodium benzenesulfonate, sodium molybdate, and sodium silicate solutions into the volumetric flask in sequence, shake well, and then adjust to the set volume with deionized water.

[0014] Preferably, the sodium benzenesulfonate is anhydrous sodium benzenesulfonate, the sodium molybdate is sodium molybdate dihydrate, and the sodium silicate is sodium silicate nonahydrate.

[0015] The beneficial effects of the high-density, temperature-resistant corrosion inhibitor for oil pumps provided by this invention are as follows:

[0016] 1) With a density greater than 1.150 g / mL, which is higher than existing completion fluids (1.050-1.120 g / mL) and petroleum (less than 1.000 g / mL), it can remain stably in the oil pump protector cavity, preventing loss;

[0017] 2) Excellent temperature resistance: It is stable in high-temperature environments of 120-180℃ for a long time, and the components do not decompose or precipitate, and the pH value changes little;

[0018] 3) High corrosion inhibition efficiency: The room temperature corrosion inhibition efficiency for 45# carbon steel and 316L stainless steel is not less than 85.00%. It can form a stable and dense corrosion-resistant film at high temperature, effectively inhibiting pitting corrosion and general corrosion.

[0019] 4) Green and environmentally friendly: The selected ingredients are free of highly toxic substances, meet environmental protection requirements, and have no significant pollution to the environment after use;

[0020] 5) Low cost: Raw materials are readily available, the preparation process is simple, no complicated equipment is required, and it is suitable for large-scale industrial applications. Attached Figure Description

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments:

[0022] Figure 1 shows the morphology of 45# carbon steel after 30 days of corrosion in the corrosion inhibitor of Example 1 at 120℃.

[0023] Figure 2 shows the morphology of 316L stainless steel after 30 days of corrosion in the corrosion inhibitor of Example 1 at 120℃. Detailed Implementation

[0024] To enable those skilled in the art to more clearly understand the content disclosed in this invention, the invention will be further described in detail below. The following description and specific embodiments are only for illustrating the principles, features, and processes of this invention, and are intended to further explain the invention, not to limit its scope. All other embodiments obtained by those skilled in the art based on the implementation examples of this invention without inventive effort are within the protection scope of this invention.

[0025] This invention provides a high-density, temperature-resistant corrosion inhibitor for oil pumps, comprising: sodium benzenesulfonate, sodium molybdate, sodium silicate, and deionized water, wherein the concentration of sodium benzenesulfonate is 180.00-200.00 g / L, the concentration of sodium molybdate is 10.00-15.00 g / L, the concentration of sodium silicate is 0.10-0.20 g / L, and the density of the corrosion inhibitor is greater than 1.150 g / mL.

[0026] The composition of the aforementioned corrosion inhibitor was determined through extensive high-temperature stability experiments and single-factor corrosion experiments. The components work synergistically: sodium benzenesulfonate provides a high-density base and enhances system stability; sodium molybdate, as an anodic corrosion inhibitor, forms a dense oxide film on the metal surface; and sodium silicate optimizes the film structure and improves corrosion resistance. Together, they achieve highly efficient corrosion inhibition under high temperature and pressure conditions of 120-180℃.

[0027] This invention provides a method for preparing the above-mentioned high-density, high-temperature corrosion inhibitor for oil pumps, comprising:

[0028] Raw material preparation: Select analytical grade sodium benzenesulfonate, sodium molybdate, sodium silicate reagents, and deionized water;

[0029] Mass calculation: Calculate the required mass of each reagent based on the target preparation volume and the concentration of each component;

[0030] Separate dissolution: Weigh each reagent according to the required mass and place each reagent in a beaker separately. Add an appropriate amount of deionized water and stir until completely dissolved to avoid premature reaction between components.

[0031] Mixing and adjusting to volume: Pour the separately dissolved sodium benzenesulfonate, sodium molybdate, and sodium silicate solutions into the volumetric flask in sequence, shake well, and then adjust to the set volume with deionized water.

[0032] Wherein, the sodium benzenesulfonate is anhydrous sodium benzenesulfonate, the sodium molybdate is sodium molybdate dihydrate, and the sodium silicate is sodium silicate nonahydrate.

[0033] Example 1

[0034] 1. Reagents and raw materials: Sodium benzenesulfonate (analytical grade, C6H5NaO3S, purity: 97%, calculated as 97% when weighing) was purchased from Shanghai E. En Chemical Technology Co., Ltd.; Sodium molybdate dihydrate (analytical grade, Na2MoO4·2H2O, purity: not less than 99.0%, calculated as 99.0% when weighing) and sodium silicate nonahydrate (analytical grade, Na2SiO3·9H2O, effective component calculated as Na2O is 19.3%-22.8%, Na2O to SiO2 content ratio is 1.03±0.03, calculated as Na2O content 19.3%, Na2O to SiO2 content ratio is 1.00 when weighing) were both purchased from Xilong Scientific Co., Ltd.; deionized water.

[0035] 2. Preparation of corrosion inhibitor (Target: 1L volume, concentration without water of crystallization: sodium benzenesulfonate 200.00g / L, sodium molybdate 15.00g / L, sodium silicate 0.20g / L):

[0036] Step 1: Calculate the mass of each reagent: Sodium benzenesulfonate: 206.19g (approximately 200.00g sodium benzenesulfonate), Sodium molybdate dihydrate: 17.80g (approximately 15.00g sodium molybdate), Sodium silicate nonahydrate: 0.53g (approximately 0.20g sodium silicate).

[0037] Step 2: Weigh each reagent according to its weighing mass and place each reagent in a separate beaker. Add an appropriate amount of deionized water and stir until completely dissolved to avoid premature reaction between components.

[0038] Step 3: Pour each solution into a 1L volumetric flask in sequence, shake well, and then dilute to 1L with deionized water to obtain the target corrosion inhibitor. The target corrosion inhibitor is composed of the following: 200.00g / L sodium benzenesulfonate + 15.00g / L sodium molybdate + 0.20g / L sodium silicate.

[0039] 3. Performance Testing:

[0040] Reactor Experiment: 45# carbon steel and 316L stainless steel samples (dimensions: 2mm×10mm×20mm) were placed in different high-temperature and high-pressure reactors, and 50mL of the above-mentioned corrosion inhibitor was added to each sample to immerse it; the samples were kept at 120℃ for 30 days.

[0041] Electrochemical experiment: A three-electrode system was used to test the potentiodynamic polarization curves of the samples (45# carbon steel and 316L stainless steel) in the corrosion inhibitor and the control completion fluid (233.00 g / L sodium chloride (purchased from Xilong Scientific Co., Ltd.) + 5.00 g / L sodium petroleum sulfonate (CAS: 68608-26-4, purchased from Guangdong Yuanfeng Chemical Technology Co., Ltd.)). The corrosion inhibition efficiency was calculated based on the change in self-corrosion current density. The temperature was room temperature (25℃).

[0042] Density measurement: The density was measured three times using a densitometer, and the average value was taken.

[0043] 4. Experimental Results:

[0044] After the reactor experiment, the corrosion of the sample surface was observed under a scanning electron microscope. The results showed that, as shown in Figures 1 and 2, a uniform and dense corrosion-resistant film was formed on the surface of both 45# carbon steel and 316L stainless steel, with no obvious corrosion. The electrochemical test results showed that the corrosion inhibition efficiencies of 45# carbon steel and 316L stainless steel in the corrosion inhibitor were 95.63% and 97.83%, respectively. The density test results showed that the density of the corrosion inhibitor was 1.185 g / mL.

[0045] Example 2

[0046] 1. The reagents and raw materials, and the preparation steps are the same as in Example 1. The target concentration when the volume is 1L and there is no water of crystallization is: sodium benzenesulfonate 180.00g / L, sodium molybdate 10.00g / L, sodium silicate 0.10g / L;

[0047] 2. Reagent weighing and mass calculation:

[0048] Sodium benzenesulfonate: 185.57g (approximately containing 180.00g of sodium benzenesulfonate), sodium molybdate dihydrate: 11.87g (approximately containing 10.00g of sodium molybdate), sodium silicate nonahydrate: 0.26g (approximately containing 0.10g of sodium silicate).

[0049] 3. Performance testing: The experimental temperature of the reactor was 180℃, and the other test conditions were the same as in Example 1;

[0050] 4. Experimental results: A uniform and dense corrosion-resistant film was formed on the surface of 45# carbon steel and 316L stainless steel, with no obvious pitting corrosion; the corrosion inhibition efficiency of 45# carbon steel was 85.09%, and that of 316L stainless steel was 86.29%; the density of the corrosion inhibitor was 1.165 g / mL.

[0051] Example 3

[0052] 1. The reagents and raw materials, and the preparation steps are the same as in Example 1. The target concentration when the volume is 1L and there is no water of crystallization is: sodium benzenesulfonate 190.00g / L, sodium molybdate 12.00g / L, and sodium silicate 0.15g / L.

[0053] 2. Reagent weighing and mass calculation:

[0054] Sodium benzenesulfonate: 195.88g (containing approximately 190.00g of sodium benzenesulfonate), sodium molybdate dihydrate: 14.24g (containing approximately 12.00g of sodium molybdate), sodium silicate nonahydrate: 0.40g (containing approximately 0.15g of sodium silicate).

[0055] 3. Performance testing: The experimental temperature of the reactor was 140℃, and the other test conditions were the same as in Example 1;

[0056] 4. Experimental results: A uniform and dense corrosion-resistant film was formed on the surface of 45# carbon steel and 316L stainless steel, with no obvious pitting corrosion; the corrosion inhibition efficiency of 45# carbon steel was 89.08%, and that of 316L stainless steel was 90.64%; the density of the corrosion inhibitor was 1.176 g / mL.

[0057] This invention achieves a balance between high density and temperature resistance of 120-180℃ through the rational compounding of sodium benzenesulfonate, sodium molybdate, and sodium silicate, utilizing the synergistic effect of each component. This allows for precise adaptation to the extreme working conditions of direct electric heating assisted extraction of heavy oil. Compared with existing technologies, the corrosion inhibitor of this invention not only boasts high corrosion inhibition efficiency and clearly defined applicable scenarios, but is also environmentally friendly, low-cost, and easy to formulate. It can be directly injected into the protective cavity of the oil pump, effectively preventing external completion fluid and oil from corroding the cavity metal, significantly extending the service life of the oil pump, and reducing production safety risks and economic losses. It has significant practical value and broad application prospects in the field of direct electric heating assisted extraction of heavy oil.

[0058] Finally, it should be further noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-density, temperature-resistant corrosion inhibitor for oil pumps, characterized in that, include: The corrosion inhibitor comprises sodium benzenesulfonate, sodium molybdate, sodium silicate, and deionized water, wherein the concentration of sodium benzenesulfonate is 180.00-200.00 g / L, the concentration of sodium molybdate is 10.00-15.00 g / L, the concentration of sodium silicate is 0.10-0.20 g / L, and the density of the corrosion inhibitor is greater than 1.150 g / mL.

2. The method for preparing the high-density, temperature-resistant corrosion inhibitor for oil pumps according to claim 1, characterized in that, include: Raw material preparation: Select analytical grade sodium benzenesulfonate, sodium molybdate, sodium silicate reagents, and deionized water; Mass calculation: Calculate the required mass of each reagent based on the target preparation volume and the concentration of each component; Individual dissolution: Weigh each reagent according to the required mass and place each reagent in a beaker separately. Add an appropriate amount of deionized water and stir until completely dissolved to avoid premature reaction between components; Mixing and volume adjustment: Pour the separately dissolved sodium benzenesulfonate, sodium molybdate, and sodium silicate solutions into volumetric flasks in sequence, shake well, and then adjust the volume to the set volume with deionized water.

3. The method for preparing the high-density, temperature-resistant corrosion inhibitor for oil pumps according to claim 2, characterized in that, The sodium benzenesulfonate is anhydrous sodium benzenesulfonate, the sodium molybdate is sodium molybdate dihydrate, and the sodium silicate is sodium silicate nonahydrate.

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