Gemini acidizing corrosion and retarding agent and preparation method thereof

Abstract

The invention relates to the technical field of oil field chemicals, in particular to a gemini acidification corrosion and retarding agent and a preparation method thereof. The preparation method comprises the following steps: heating stearic acid, dropwise adding triethylene tetramine, sequentially adding zinc particles and xylene, and stirring to obtain a reaction system; placing the reaction system in a nitrogen environment, and carrying out programmed heating to obtain an intermediate product; and mixing the intermediate product with sodium chloroacetate and an absolute ethyl alcohol solvent, and carrying out quaternization reaction to obtain a target product. The product disclosed by the invention is good in solubility in acid liquor, weak in tackifying capacity, low in acid liquor viscosity, good in flowability in a pipeline, easy to inject into a stratum during construction, high in flowback rate after construction is finished, small in secondary damage to a reservoir and suitable for acidification operation of a low-permeability carbonate reservoir; compared with the prior art, the acid solution retarding agent has good acid solution retarding performance, does not cause the increase of the viscosity of the acid solution, has a good retarding effect in carbonate rocks, can permeate to the deep part of a reservoir, and is beneficial to pumping and flowback due to small viscosity of the retarding acid solution; the preparation process is simple, mild in reaction, convenient to operate and low in preparation cost.

Description

Technical Field

[0001] The invention relates to the technical field of oilfield chemicals, and in particular to a gemini acidizing corrosion inhibitor and a preparation method thereof. Background Art

[0002] As the development time of oil wells increases, underground oil wells are clogged by oil sludge, iron scale, clay minerals and other sediments in sewage. At the same time, due to the density of the reservoir itself, the permeability of the near-well area is low. At present, acidizing is one of the effective methods to improve the above phenomenon. However, in the acidizing construction, due to the rapid reaction of acid and rock, the acidizing distance is short, and it is difficult to achieve the purpose of deep acidizing.

[0003] At present, the traditional slow acid system method in carbonate reservoirs mainly relies on polymers to increase the viscosity of the acid solution and inhibit H + However, polymers with molecular weights exceeding one million and containing hydrophilic groups are easily adsorbed in tiny pores in the oil and gas reservoir space, blocking the permeation channels and causing secondary damage to the reservoir. As for emulsified acid, its properties will lead to unfavorable high-pressure friction pressure during pumping; and foam acid is limited by the stability of the foam and is difficult to use under high temperature and high pressure conditions.

[0004] The document with patent number "CN201010251664.7" discloses "A Slowing Corrosion Inhibitor", whose raw materials are: fatty acid, diethylenetriamine, dichlorobutane, formaldehyde, and emulsifier, which is prepared through the following steps: the first step is to add fatty acid and diethylenetriamine into a reactor for condensation, stir and turn on the heater, when the temperature rises to 150°C, open the vacuum pump valve, add water to form a heterocyclic mixture, then close the heater and vacuum pump valve, add dichlorobutane dropwise, keep warm for 4 hours, and form an imidazolinium cation; the second step is to add formaldehyde into a compound reactor, and then add the imidazolinium cation obtained in the first step into the compound reactor, heat to 80°C, and stir for 30 minutes; the third step is to add the emulsifier into the compound reactor, stir for 30 minutes, and it is ready. The existing problems are: 1. Due to the excessive presence of hydrophobic groups, the product is difficult to dissolve in water, resulting in unsatisfactory corrosion inhibition; 2. Due to the single-chain characteristics of the product, the corrosion inhibition and rate-retarding effects are unsatisfactory; 3. The preparation method is divided into three steps, and the process is complicated. Summary of the invention

[0005] The purpose of the present invention is to provide a gemini acid corrosion inhibitor and a preparation method thereof, so as to solve the problems of the prior art products being poorly soluble in water, having unsatisfactory corrosion inhibition and retarding effects, and having a complicated preparation method.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] In a first aspect, the present invention provides a gemini acid corrosion inhibitor having a structure as shown in formula (1):

[0008]

[0009] In a second aspect, the present invention provides a method for preparing a gemini acid corrosion inhibitor, comprising the following steps:

[0010] Step 1: Heat stearic acid to 120°C under nitrogen atmosphere, drop triethylenetetramine into the stearic acid, then add zinc particles and xylene in sequence, stir to obtain a reaction system, and continue heating for 2 hours;

[0011] Step 2: raising the temperature of the reaction system to 190-200° C. and reacting for 4 h to obtain an intermediate product;

[0012] Step 3: Add sodium chloroacetate and anhydrous ethanol to the reaction system to carry out quaternization reaction to obtain the target product.

[0013] Furthermore, the above raw materials, measured by mass, include 20 parts of stearic acid, 3 parts of triethylenetetramine, 1 part of xylene, 4 parts of sodium chloroacetate, 1 part of zinc particles, and 3 parts of anhydrous ethanol.

[0014] Furthermore, in the above step 2, programmed temperature rise refers to heating from 120°C to 190-200°C with a temperature rise of 20°C every 2 hours, and then maintaining the temperature at 190-200°C for 4-5 hours.

[0015] Furthermore, the method for preparing the above-mentioned gemini acid corrosion inhibitor is characterized in that in the step 2, the pH is controlled to be 9-10 for the quaternization reaction.

[0016] Furthermore, in the above step 2, the temperature is controlled to be 85-90° C. and the time is 4-5 hours to carry out the quaternization reaction.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The acidification retarder of the present invention is a gemini acidification corrosion retarder. Due to the special structure of the gemini, the electrostatic repulsion between them is weakened under the action of the covalent bond of the connecting group, and the distance between the molecules is shortened, so that the molecules of the double-letter structure are closely arranged on the interface, and the hydrophobic effect is enhanced, so that it can be adsorbed on the rock surface, thereby effectively slowing down the contact between hydrogen ions and rocks, achieving the purpose of reducing the acid-rock reaction rate and extending the acidification distance, and achieving deep acidification. Its imidazoline structure increases the adsorption of metals, delays the contact between hydrogen ions and metals, and realizes metal corrosion protection. In addition, the present invention introduces ethylcarboxyl on the imidazoline ring, which can change its original oil-soluble state into a water-soluble state, which is conducive to rapid dissolution in acid solution. Therefore, the gemini acidizing corrosion retarder of the present invention has good solubility in acid solution, weak viscosity increasing ability, low viscosity of acid solution, good fluidity in pipeline, easy injection into formation during construction, high flowback rate after construction, little secondary damage to reservoir, and is suitable for acidizing operation of low permeability carbonate reservoir.

[0019] 2. The present invention uses stearic acid and triethylenetetramine for synthesis, uses xylene as a water-carrying agent, uses zinc particles as a catalyst to obtain an intermediate, and then uses sodium chloroacetate as a quaternizing agent to perform a quaternization reaction to obtain a gemini acid corrosion retarder, and the obtained product has high purity. The present invention belongs to a surfactant, has a small relative molecular weight, and has good acid solution retarding performance while not causing an increase in acid solution viscosity.

[0020] 3. The present invention promotes effective collision between molecules by reasonably controlling the reaction temperature and time. The preparation process is simple, the reaction is mild, the operation is convenient, and the preparation cost is low.

[0021] 4. The Gemini corrosion retarder is added to the retarding acid, which has a good retarding effect in carbonate rocks and can penetrate deep into the reservoir. The retarding acid has a low viscosity, which is conducive to pumping and flowback; it has a good corrosion inhibition effect on N80 steel sheets. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is the graph of NaOH consumption of bare acid solution and retarded acid solution prepared by Gemini corrosion retarder after sampling at different time periods;

[0023] Figure 2 This is a comparison chart of the phenomena of N80 steel sheet reacting in bare acid solution and retarded acid solution prepared by Gemini corrosion retarder for 4 hours;

[0024] Figure 3 This is the infrared spectrum of Gemini corrosion inhibitor. DETAILED DESCRIPTION

[0025] The following is a clear and complete description of the technical solution of the present invention in combination with the embodiments of the present invention and the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Embodiment 1, a method for preparing a gemini acid corrosion inhibitor, comprising the following steps:

[0027] Step 1, in a three-necked flask, heat 20 parts of stearic acid by mass to 120°C, drop 3 parts of triethylenetetramine into the stearic acid, then add 1 part of zinc particles and 1 part of xylene in sequence, introduce nitrogen, maintain the reaction temperature at 120°C, control the stirring rate to 200 r / min and react for 2 hours;

[0028] Step 2, program the system temperature, wherein the program temperature rise refers to heating from 120°C to 190°C by increasing the temperature by 20°C every 2 hours, then maintaining the temperature at 190°C for 4 hours, and performing acylation reaction and cyclization reaction during the temperature rise process to obtain an intermediate product;

[0029] Step 3: Control the system temperature to 90°C, add 4 parts of sodium chloroacetate and 3 parts of anhydrous ethanol to the reaction system, use a 5% NaOH solution to control the pH to 9, take out after quaternization reaction for 4 hours, and obtain the final product, a gemini acid corrosion inhibitor.

[0030] Embodiment 2, a method for preparing a gemini acid corrosion inhibitor, comprising the following steps:

[0031] Step 1, in a three-necked flask, heat 20 parts of stearic acid by mass to 120°C, drop 3 parts of triethylenetetramine into the stearic acid, then add 1 part of zinc particles and 1 part of xylene in sequence, introduce nitrogen, maintain the reaction temperature at 120°C, control the stirring rate to 300 r / min and react for 2 hours;

[0032] Step 2, program the system temperature, wherein the program temperature rise refers to heating from 120°C to 200°C with a temperature rise of 20°C every 2 hours, then maintaining the temperature at 200°C for 4 hours, and performing acylation reaction and cyclization reaction during the temperature rise to obtain an intermediate product;

[0033] Step 3: Control the system temperature to 90° C., add 4 parts of sodium chloroacetate and 3 parts of anhydrous ethanol into the system, use a 5% NaOH solution to control the pH to 10, and take out after quaternization reaction for 5 hours to obtain the final product, a gemini acid corrosion inhibitor.

[0034] In the above embodiments, embodiment 2 is the best embodiment, and the gemini acid corrosion inhibitor prepared in embodiment 2 is evaluated:

[0035] 1. In this experiment, when the single factor optimization method was used to optimize the preparation conditions of the Gemini corrosion inhibitor, the Gemini corrosion inhibitor was evaluated with reference to the petroleum and natural gas industry standards SY / T5886-2018 "Evaluation Method for Performance of Acidizing Working Fluid" and SY / T5405-2019 "Performance Test Method and Evaluation Index of Corrosion Inhibitor for Acidizing".

[0036] 1.1 Evaluation method of the retarding performance of gemini acid corrosion inhibitor

[0037] Add 100g 15% HCl + 5% formic acid solution to a 250mL beaker, then add 0.30g of the Gemini corrosion retarder prepared in Example 1 of the present invention, stir and dissolve, prepare a 0.3% retarding acid solution, seal it well, place it in a 50°C water bath for preheating for 10min, put it in a carbonate natural core, and react for 30min. The acid etching reaction starts at 1min, 4min, 7min, 10min, 15min, 20min, 25min... time period, take 6ml of acid solution, use it and titrate it with 1mol / L standard NaOH solution, titrate each sample three times in parallel, and record the relationship between the consumption of the titration NaOH solution and time.

[0038] 1.2 Evaluation method of corrosion inhibition performance of gemini acid corrosion inhibitor

[0039] Using N80 steel sheets, a corrosion inhibition experiment was carried out on N80 steel by the static weight loss method. Two N80 steel sheets were taken out, washed with water, acetone and anhydrous ethanol in turn, and then dried with cold air. Then, they were placed in an oven to dry for 20 minutes and then weighed. After soaking for 4 hours at a simulated formation temperature of 60°C, they were taken out, washed and dried, and weighed again to calculate the corrosion inhibition rate.

[0040] 2. Performance evaluation of gemini acid corrosion inhibitor:

[0041] In this experiment, the corrosion inhibition performance was tested by testing the etching rates of bare acid and Gemini corrosion inhibitor solution.

[0042] 2.1 Retarding performance of gemini acid corrosion inhibitor

[0043] Add 100g of 20% dilute hydrochloric acid solution to two 250mL beakers respectively, and then add 0.3g of Gemini corrosion retarder to one of them, stir and dissolve at room temperature, prepare bare acid and 0.3% Gemini corrosion retarder solution, put it in a constant temperature water bath at 60℃ and preheat for 10min for standby use. Put in carbonate natural core. The acid etching reaction starts according to the time period of 1min, 4min, 7min, 10min, 15min, 20min, 25min..., take 6mL of acid solution, and titrate with 1mol / L standard NaOH solution after use. Each sample is titrated three times in parallel, and the relationship between the consumption of titration NaOH solution and time is recorded. Figure 1 This is a graph showing the average change in the amount of 1 mol / L standard NaOH solution required to calibrate 2 mL of residual acid over time. Figure 1 It can be seen that the amount of NaOH consumed by the bare acid solution decreases rapidly with time before 30 minutes, and there is no obvious change in the later period, indicating that the natural core reacts quickly with the acid solution in the early stage and reaches the maximum acid etching effect in about 30 minutes. On the contrary, the NaOH consumption rate of the compound acid solution system is relatively slow overall, and it will continue to react after 30 minutes, indicating that the compound acid solution system greatly slows down the acid-rock reaction rate and has a good slowing effect.

[0044] 2.2 Corrosion inhibition performance of gemini acid corrosion inhibitor

[0045] Add 100g of 20% dilute hydrochloric acid solution to two 250mL beakers respectively, and then add 0.3g of Gemini corrosion inhibitor to one of them, stir and dissolve at room temperature to prepare bare acid and 0.3% Gemini corrosion inhibitor solution, put it into a constant temperature water bath at 60℃ and preheat for 10min for use. The corrosion inhibition experiment of N80 steel was carried out by static weight loss method. After soaking for 4h at simulated formation temperature of 60℃, the steel was taken out and the mass change before and after was weighed. Table 1 is the corrosion data table of bare acid solution and acid system on N80 steel sheet. It can be seen from Table 1 that the corrosion inhibition rate is as high as 96.74%. Figure 2 The experimental comparison phenomenon proves that the acidizing solution system has a good corrosion inhibition effect on steel sheets.

[0046] Table 1

[0047]

[0048] 3. Structural characterization of the gemini acid corrosion inhibitor of the present invention:

[0049] The infrared absorption spectrum of the Gemini corrosion inhibitor prepared in Example 1 was measured using a Thermo Fisher Nicolet 6700 infrared spectrometer. Figure 3 .Depend on Figure 3It can be seen that 1649.7 and 1093.4 can obtain the cyclic C=N and CN functional groups, indicating the appearance of imidazoline; 1749 and 1209.3 can prove the appearance of -CH2COO- functional group, and 1550 and 1434.5 can prove the successful quaternization. It can be inferred that the structure of the target product is consistent with the design.

[0050] The above is an explanation of the specific implementation of the present invention, rather than a limitation of the present invention. Those skilled in the relevant technical field can also make various equivalent technical solutions without departing from the scope of the present invention, so all equivalent technical solutions should be included in the protection scope of the present invention.

Claims

1. A gemini acid corrosion inhibitor, characterized in that: It has the structure shown in formula (1):

2. The method for preparing a gemini acid corrosion inhibitor according to claim 1, characterized in that : Includes the following steps: Step 1: Heat stearic acid to 120°C under nitrogen atmosphere, drop triethylenetetramine into the stearic acid, then add zinc particles and xylene in sequence, stir to obtain a reaction system, and continue heating for 2 hours; Step 2: raising the temperature of the reaction system to 190-200° C. to obtain an intermediate product; Step 3: adding sodium chloroacetate and anhydrous ethanol solvent into the reaction system to carry out quaternization reaction to obtain the target product.

3. The method for preparing a gemini acid corrosion inhibitor according to claim 2, characterized in that The raw materials, measured by mass, include 20 parts of stearic acid, 3 parts of triethylenetetramine, 1 part of xylene, 4 parts of sodium chloroacetate, 1 part of zinc particles, and 3 parts of anhydrous ethanol.

4. The method for preparing a gemini acid corrosion inhibitor according to claim 2, characterized in that: In the step 2, the programmed temperature rise refers to heating from 120°C to 190-200°C with a temperature rise of 20°C every 2 hours, and then maintaining the temperature at 190-200°C for 4-5 hours.

5. The method for preparing a gemini acid corrosion inhibitor according to claim 2, characterized in that: In the step 3, the pH is controlled to be 9-10 for quaternization reaction.

6. The method for preparing a gemini acid corrosion inhibitor according to claim 5, characterized in that: In the step 3, the temperature is controlled to be 85-90° C. and the time is 4-5 hours to carry out the quaternization reaction.

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