A nano corrosion inhibitor and scale inhibitor and its preparation method and application

Abstract

The present invention belongs to the technical field of oilfield exploitation, and specifically relates to a nano-corrosion and scale inhibitor, and its preparation method and application. The nano-corrosion and scale inhibitor of the present invention has a structure shown in formula (1), wherein n=13, 15, or 17. The present invention first uses phosphoric acid, sodium chromate, and dicyclohexylamine to react, and then reacts the reaction product with a dialkoxy dithiophosphate pyridinium salt to generate the nano-corrosion and scale inhibitor; Cr=O and P=S in formula (1) can chemically bond with the iron atoms on the surface of the metal substrate to inhibit corrosion; N(C6H 11 The steric hindrance effect of nanomaterials can reduce the impact of corrosion and scaling ions on the metal substrate. The interfacial effect of the nanomaterial allows the corrosion and scale inhibitor of the present invention to form a dense film on the surface of the metal substrate, achieving excellent corrosion and scale inhibition effects. It is suitable for the corrosion and scale prevention of wellbore strings in oil and water wells in oil and gas fields or surface pipelines. #imgabs0#

Description

Technical Field

[0001] The invention belongs to the technical field of oilfield exploitation, and particularly relates to a nano corrosion and scale inhibitor and a preparation method and application thereof. Background Art

[0002] Currently, corrosion and scale inhibitors used in oil and gas fields mostly work by forming a protective film on the surface of the metal substrate and inhibiting the growth of scale nuclei in the solution. These corrosion and scale inhibitors generally suffer from loose bonding with the substrate surface and susceptibility to erosion, which directly impacts their effectiveness. In recent years, nanomaterials have been gradually applied to the oilfield chemical industry, and their application in oil and gas field corrosion and scale prevention has also been increasingly extensive. By preparing traditional corrosion and scale inhibitors at the nanoscale and leveraging the strong interfacial activity of nanomaterials, their effectiveness can be significantly improved.

[0003] Chinese invention patent CN112410005A discloses a multifunctional corrosion and scale inhibitor and its preparation method. Combining corrosion inhibitors, scale inhibitors, wax inhibitors, and silica nanocolloids, it simultaneously provides multiple functions, including corrosion prevention, scale prevention, wax prevention, and injection enhancement. However, this formulation does not adhere tightly to the substrate surface, resulting in a short shelf life. Furthermore, due to the large number of ingredients, the production process is complex and unsuitable for high-sulfur, high-temperature, and high-pressure environments.

[0004] Chinese invention patent CN111139056A discloses a long-lasting, anti-scaling, coated proppant and its preparation method. Composed of a proppant core, a corrosion and scale inhibitor, and a protective layer made of a soluble nanomaterial, this proppant boasts advantages such as long-lasting effectiveness and independence from well type. However, this proppant is limited to downhole applications and suffers from the same issues as complex production and difficult operation. Summary of the Invention

[0005] The purpose of the present invention is to provide a nano corrosion and scale inhibitor to solve the problems of existing corrosion and scale inhibitors not being tightly bound to the substrate surface and being easily eroded, and to have better corrosion and scale inhibition effects.

[0006] The second object of the present invention is to provide a method for preparing the above-mentioned nano corrosion and scale inhibitor, which has a simple preparation process and is easy to operate, and solves the problems of the existing corrosion and scale inhibitor preparation process being complicated and difficult to operate.

[0007] The third object of the present invention is to provide the application of the above-mentioned nano corrosion and scale inhibitor in the corrosion and scale prevention of oil and water well pipes in oil and gas fields or ground pipelines, so as to solve the problem of the narrow application range of existing corrosion and scale inhibitors.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] A nano corrosion inhibitor and scale inhibitor having a structure shown in formula (1):

[0010] Where n=13, 15, 17.

[0011] The Cr=O bond and P=S bond in the nano corrosion and scale inhibitor of the present invention can be chemically bonded with the iron atoms on the surface of the metal matrix to inhibit corrosion; N(C6H 11 )2's steric hindrance effect can reduce the impact of corrosion and scaling ions on the metal matrix; the corrosion and scale inhibitor of the present invention is nano-level, and utilizes the interfacial effect of nanoparticles to firmly combine with the metal matrix to form a dense film on its surface, which plays a corrosion-inhibiting role. It can also combine with scaling nuclei in the solution to prevent scaling deposition and play a scaling-inhibiting role.

[0012] In order to better improve the use effect of the nano corrosion inhibitor and scale inhibitor, preferably, the particle size of the nano corrosion inhibitor and scale inhibitor is 20 to 50 nm.

[0013] The preparation method of the nano corrosion inhibitor and scale inhibitor of the present invention comprises the following steps:

[0014] (1) Add phosphoric acid, sodium chromate and dicyclohexylamine to a solvent and react at 60-80°C;

[0015] (2) adding a bis-alkoxy dithiophosphate pyridinium salt to the product of step (1) and continuing the reaction at 60-80° C. under ultrasonic conditions, separating the solid and the liquid after the reaction is completed, and drying the solid to obtain a nano corrosion inhibitor; the molecular formula of the bis-alkoxy dithiophosphate pyridinium salt is (C n H 2n+1 CH2O)2PS(SHNC5H5), n=13,15,17.

[0016] The present invention first uses phosphoric acid, sodium chromate and dicyclohexylamine to react, and then the reaction product reacts with a dialkoxy dithiophosphate pyridinium salt to generate a structure containing a Cr=O bond, a P=S bond and an N(C6H 11 )2 nano-scale corrosion and scale inhibitor; its Cr=O bond and P=S bond can chemically bond with the iron atoms on the surface of the metal matrix to inhibit corrosion; N(C6H 11 )2's steric hindrance effect can reduce the impact of corrosion and scaling ions on the metal matrix; and the present invention adopts dialkoxy dithiophosphate pyridinium salt as a modifier, and under the action of ultrasound, the generated nano corrosion inhibitor and scale inhibitor is controlled at the nano level, and the interface effect of the nanoparticles is utilized to firmly combine with the metal matrix to form a dense film on its surface, which plays a corrosion inhibition role, and can also combine with the scaling nuclei in the solution to prevent scaling deposition and play a scaling inhibition role; at the same time, the nano corrosion inhibitor and scale inhibitor prepared by the present invention does not belong to a compound system, and the preparation process is simple and easy to operate.

[0017] In order to ensure a higher reaction yield of the raw materials, preferably, the mass ratio of the phosphoric acid, sodium chromate, dicyclohexylamine and dialkoxy dithiophosphate pyridinium salt is 1: (1.4-1.6): (0.5-0.6): (5.5-7.0).

[0018] Preferably, in step (1), the solvent is water, and the amount of water used is 40 to 60 mL per 1 g of phosphoric acid.

[0019] Preferably, in step (1), the reaction time is 5 to 10 minutes.

[0020] Preferably, in step (2), the ultrasonic power of the ultrasound is 60 to 120 W·cm -2 , frequency 20~30kHz.

[0021] Preferably, in step (2), the ultrasonic reaction time is 60 to 90 minutes.

[0022] An application of the nano corrosion and scale inhibitor in the anti-corrosion and anti-scaling of oil and water wells in oil and gas fields or surface pipe networks.

[0023] The nano corrosion and scale inhibitor of the present invention can form a dense film on the surface of the metal substrate, is densely bonded to the surface of the metal substrate, is resistant to erosion, has good corrosion and scale inhibition effects, and has a wide range of applications.

[0024] Preferably, the oil and gas field is a high-sulfur gas field.

[0025] The nano corrosion and scale inhibitor of the present invention uses a modifier to control the agent particles at the nano level on the basis of the traditional corrosion and scale inhibition mechanism, thereby greatly enhancing the binding force between the nano corrosion and scale inhibitor and the steel matrix and the scale-forming crystal nuclei, and significantly enhancing the corrosion and scale inhibition effect. The interfacial effect of the nano material makes the nano corrosion and scale inhibitor applicable to various oilfield environments such as oil, gas and water with high sulfur content, high temperature, high pressure and high salinity. DETAILED DESCRIPTION

[0026] The present invention first uses phosphoric acid, sodium chromate, and dicyclohexylamine to react at 60-80° C. to obtain a product (A), and then the product A is reacted with a dialkoxy dithiophosphate pyridinium salt (B) under ultrasonic conditions at 60-80° C. After the reaction is completed, the solid and liquid are separated, and the solid is dried to obtain a nano corrosion and scale inhibitor (C). The reaction process is shown in formulas (2) and (3).

[0027]

[0028]

[0029] The embodiments of the present invention will be further described below with reference to specific examples.

[0030] 1. Specific examples of the nano corrosion inhibitor and scale inhibitor of the present invention are as follows:

[0031] Example 1

[0032] The nano corrosion inhibitor and scale inhibitor of this embodiment has the structural formula:

[0033]

[0034] In other embodiments, corresponding to formula (1), n=15 or n=17.

[0035] 2. The specific examples of the preparation method of the nano corrosion inhibitor and scale inhibitor of the present invention are as follows:

[0036] Example 2

[0037] The preparation method of the nano-corrosion and scale inhibitor of this embodiment comprises the following steps:

[0038] (1) Add 10 g of phosphoric acid, 14 g of sodium chromate, and 5 g of dicyclohexylamine to a 1 L reactor, add purified water to half the reactor volume, control the temperature at 80 ° C, and react for 5 min;

[0039] (2) Slowly add 55g of didodecyloxy dithiophosphate pyridinium salt (n=15) to the product of step (1) at 80°C under ultrasonic conditions, and the ultrasonic power is 60W·cm -2 , frequency 20kHz, ultrasonic reaction for 60min, hot washing and vacuum filtration, and drying to obtain a gray-white powder sample, namely the nano corrosion inhibitor and scale inhibitor.

[0040] Example 3

[0041] The preparation method of the nano-corrosion and scale inhibitor of this embodiment comprises the following steps:

[0042] (1) Add 10 g of phosphoric acid, 16 g of sodium chromate, and 6 g of dicyclohexylamine to a 1 L reactor, and add purified water to half the reactor volume. Control the temperature at 60°C and the reaction time for 10 min.

[0043] (2) Slowly add 70g of didodecyloxy dithiophosphate pyridinium salt (n=17) to react with the product of step (1) at 60°C under ultrasonic conditions, with an ultrasonic power of 120W·cm -2 , frequency 30kHz, ultrasonic reaction for 90min, hot washing and vacuum filtration, and drying to obtain a gray-white powder sample, namely the nano corrosion inhibitor and scale inhibitor.

[0044] Example 4

[0045] The preparation method of the nano-corrosion and scale inhibitor of this embodiment comprises the following steps:

[0046] (1) Add 10 g of phosphoric acid, 15 g of sodium chromate, and 6 g of dicyclohexylamine to a 1 L reactor, and add purified water to half the reactor volume. Control the temperature at 70°C and the reaction time for 8 min.

[0047] (2) Slowly add 60g of didodecyloxy dithiophosphate pyridinium salt (n=15) to react with the product of step (1) at 70°C under ultrasonic conditions, with an ultrasonic power of 120W·cm -2 , frequency 20kHz, ultrasonic reaction for 70min, hot washing and vacuum filtration, and drying to obtain a gray-white powder sample, namely the nano corrosion inhibitor and scale inhibitor.

[0048] Examples 5 to 11

[0049] The steps of the preparation method of the nano-corrosion and scale inhibitor of Examples 5 to 11, the reaction temperatures of step (1) and step (2), and the reaction time of step (1) are the same as those of Example 2. The other components and experimental conditions are shown in Table 1:

[0050] Table 1 Reactant components and reaction conditions of Examples 5 to 11

[0051]

[0052] 3. Comparative Examples

[0053] Comparative Example 1

[0054] The preparation method of the corrosion inhibitor and scale inhibitor of this comparative example is different from that of Example 2 in that: in the didodecyloxy pyridinium dithiophosphate, n=14.

[0055] Comparative Example 2

[0056] The preparation method of the corrosion inhibitor and scale inhibitor of this comparative example is different from that of Example 2 in that: in the didodecyloxy pyridinium dithiophosphate, n=16.

[0057] Comparative Example 3

[0058] The preparation method of the corrosion inhibitor and scale inhibitor of this comparative example is different from that of comparative example 2 in that the ultrasonic reaction time is 80 minutes.

[0059] IV. Experimental Examples

[0060] Experimental Example 1

[0061] The particle sizes of the corrosion and scale inhibitors prepared in Examples 2 to 11 and Comparative Examples 1 to 3 were measured. The results are shown in Table 2.

[0062] Table 2 Particle size of corrosion and scale inhibitors

[0063]

[0064] As can be seen from Table 1 above, the particle size of the nano-corrosion and scale inhibitors prepared in Examples 2 to 11 is 22 to 50 nm. The interfacial effect of the nanomaterial enables the corrosion and scale inhibitors of the present invention to be firmly bonded to the metal matrix, forming a dense film on the surface of the metal substrate, which plays a corrosion inhibition role. It can also combine with scale nuclei in the solution to prevent scale deposition.

[0065] Experimental Example 2

[0066] The corrosion and scale inhibitor prepared by the present invention is dissolved in water to prepare a solution with a concentration of 1%, and then 100 ppm (final concentration) is added to oil and gas field water. A certain size of steel P110 is immersed in it and left to stand for a period of time. It is found that a dense film is formed on the surface of the steel. The formation of the dense film can play a corrosion inhibition role, especially reducing the impact of pitting or pitting on the steel; the dense film has a certain degree of adhesion with the steel surface, and remains intact under continuous washing under running water, has a certain scouring resistance, and needs to be brushed off with a brush when cleaning.

[0067] Experimental Example 3

[0068] The corrosion and scale inhibitor of the present invention was applied to a high-sulfur wastewater treatment process in a gas field. The corrosion and scale inhibitors synthesized in Examples 2 to 4 and Comparative Examples 1 to 3 were selected and dissolved in water to prepare a solution with a concentration of 1%. Then, the solution was gradually added to the high-sulfur wastewater at addition amounts of 0 ppm, 50 ppm, 100 ppm, 150 ppm, and 200 ppm (final concentration) from low to high. Referring to SY / T5329-2012 "Water Quality Indicators and Analysis Methods for Water Injection in Clastic Reservoirs" and SY / T 5673-1993 "Performance Evaluation Methods for Scale Inhibitors for Oilfields", the corrosion inhibition rate and calcium carbonate scale prevention rate of each sample were tested and measured, as shown in Tables 3 and 4.

[0069] Table 3 Changes in corrosion inhibition rate and calcium carbonate anti-scaling rate at different addition amounts of the nano-corrosion inhibitors synthesized in Examples 2 to 4

[0070]

[0071] Table 4 Changes in corrosion inhibition rate and calcium carbonate anti-scaling rate at different addition amounts of the corrosion and scale inhibitors synthesized in Comparative Examples 1 to 3

[0072]

[0073] It can be seen from Tables 3 and 4 above that the corrosion inhibition rate and scale prevention rate of the nano corrosion inhibitors and scale inhibitors synthesized in Examples 2 to 4 of the present invention are much greater than the corrosion inhibition rate and scale prevention rate of the corrosion inhibitors and scale inhibitors synthesized in Comparative Examples 1 to 3. When the dosage of the nano corrosion inhibitors and scale inhibitors synthesized in the present invention is 100 ppm, the corrosion inhibition rate and scale prevention rate can both reach more than 85%, and the corrosion inhibition and scale inhibition effect is good.

Claims

1. A nano corrosion inhibitor, characterized in that: It has the structure shown in formula (1): Where n=13, 15, 17.

2. The nano corrosion inhibitor and scale inhibitor according to claim 1, characterized in that: The particle size of the nano corrosion inhibitor and scale inhibitor is 20 to 50 nm.

3. The method for preparing the nano corrosion inhibitor and scale inhibitor according to claim 1, wherein: The following steps are involved: (1) Add phosphoric acid, sodium chromate and dicyclohexylamine to a solvent and react at 60-80°C; (2) adding a bis(alkoxy)dithiophosphate pyridinium salt to the product of step (1) and continuing the reaction at 60-80° C. under ultrasonic conditions, separating the solid and the liquid after the reaction is completed, and drying the solid to obtain a nano-corrosion and scale inhibitor; The molecular formula of the dialkoxy dithiophosphate pyridinium salt is (C n H 2n+1 CH2O)2PS(SHNC5H5), n=13,15,17.

4. The method for preparing the nano corrosion inhibitor and scale inhibitor according to claim 3, characterized in that: The mass ratio of the phosphoric acid, sodium chromate, dicyclohexylamine and dialkoxy dithiophosphate pyridinium salt is 1: (1.4-1.6): (0.5-0.6): (5.5-7.0).

5. The method for preparing the nano corrosion inhibitor and scale inhibitor according to claim 3, characterized in that: In step (1), the solvent is water, and the amount of water used is 40 to 60 mL per 1 g of phosphoric acid.

6. The method for preparing the nano corrosion inhibitor and scale inhibitor according to any one of claims 3 to 5, characterized in that: In step (1), the reaction time is 5 to 10 minutes.

7. The method for preparing the nano corrosion inhibitor and scale inhibitor according to claim 3, characterized in that: In step (2), the ultrasonic power of the ultrasound is 60 to 120 W·cm -2 , frequency 20~30kHz.

8. The method for preparing the nano corrosion inhibitor and scale inhibitor according to claim 3 or 7, characterized in that: In step (2), the ultrasonic reaction time is 60 to 90 minutes.

9. Use of the nano corrosion inhibitor and scale inhibitor according to claim 1 in the corrosion and scale prevention of oil and water well pipes or surface pipe networks in oil and gas fields.

10. The use according to claim 9, characterized in that The oil and gas field is a high-sulfur gas field.

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