CN111808593A

CN111808593A - Corrosion inhibitor for carbon dioxide flooding combined bacterial acidification and preparation method thereof

Info

Publication number: CN111808593A
Application number: CN202010694370.5A
Authority: CN
Inventors: 时维才; 刘宏芳; 吕红梅; 余晓玲; 王军磊
Original assignee: China Petroleum and Chemical Corp; Sinopec Jiangsu Oilfield Co
Current assignee: China Petroleum and Chemical Corp; Sinopec Jiangsu Oilfield Co
Priority date: 2020-07-17
Filing date: 2020-07-17
Publication date: 2020-10-23
Anticipated expiration: 2040-07-17
Also published as: CN111808593B

Abstract

The invention discloses a corrosion inhibitor for carbon dioxide flooding combined bacterial acidification, which comprises the following components: 1-35 wt% of arecoline quaternary ammonium salt, 1-20 wt% of mixed oleic imidazoline, 5-15 wt% of 1,3, 5-tri (2-hydroxyethyl) -hexahydro-s-triazine, 5-10 wt% of thiourea, 1-5 wt% of monoethanolamine, 10-20 wt% of 2-phosphate-1, 2, 4-tricarboxylic acid butane and 0-70 wt% of water. The inhibitor prepared by the invention can be used for oil wells with high temperature, high carbon dioxide partial pressure and rich harmful microorganisms, especially in a coexistence system of various harmful bacteria, and has the advantages of low usage amount and good effect.

Description

Corrosion inhibitor for carbon dioxide flooding combined bacterial acidification and preparation method thereof

Technical Field

The invention relates to the technical field of oil exploitation, in particular to an inhibitor for an oil well which is suitable for high temperature and high partial pressure of carbon dioxide and is rich in harmful microorganisms and a preparation method thereof.

Background

In the petroleum industry, the use of carbon dioxide flooding is one of the important methods for increasing oil recovery (EOR). It has been shown that with CO₂Oil displacement technology EOR-CO₂The method can greatly improve the recoverable yield, daily output and recovery ratio of the oil field. The technology is widely applied abroad, and obvious effect is achieved. In this respect, the united states was first and since the 60's of this century, the united states fully utilized much of the CO found in the eastern foot of rocky mountain₂Gas fields (reservoirs) with widespread adoption of CO in fields near hydrocarbon-bearing basins₂The oil displacement technology is used for tertiary oil recovery and has quite obvious benefits. Practice shows that the EOR-CO is utilized₂The technology can improve the recoverable reserves of the oil field by several times. For example, in a Brady field on a Montana Wittie Grass (Sweet grass) swell, the recovery of the Brady field is improved by 4 times or more by a technique of flooding crude oil with a high concentration of carbon dioxide that is abundant in Kevin Sunburst (Kevin Sunburst) vault structures at the swell apexes. In addition, MCElmo CO of Colorado₂Bravo (Bravo) CO from gas fields and New Mexico₂Gas fieldAnd the like have also long been used in tertiary oil recovery operations in oil fields near them.

CO₂Oil displacement has two modes: miscible flooding and immiscible flooding. Miscible flooding refers to CO under the condition of thin oil reservoir₂CO which is easy to generate miscible phase with crude oil and is in a supercritical state under miscible phase pressure₂Can reduce the interfacial tension of the affected oil and water, CO₂The higher the injection concentration is, the lower the oil-water phase interfacial tension is, and the easier the crude oil is to be displaced. CO generation by adjusting slugs of injected gas₂The miscible phase is formed, and the increase range of the crude oil recovery rate can be improved. Immiscible CO₂Flooding is mainly aimed at the exploitation of thick oil, and the main mechanism is as follows: reducing the viscosity of crude oil, improving the oil-water fluidity ratio, expanding the crude oil, emulsifying and reducing the pressure for exploitation. CO2₂Solubility in oil increases with increasing pressure, and when pressure decreases, CO₂From saturated CO₂Overflow and drive the crude oil to form dissolved gas drive. Gaseous CO₂The carbonic acid generated by the reaction of the penetrated stratum and the stratum water can effectively improve the permeability of the stratum around the shaft and improve the oil displacement efficiency. With CO₂Another mining mechanism associated with flooding is by CO₂The free gas formed can partially replace the residual oil in the reservoir. Under reservoir conditions (e.g., 110 deg.C, 25MPa), carbon dioxide has a high solubility in water, which is 81-87% lower in tubing and surface pipelines than under reservoir conditions. As the solubility of carbon dioxide in water decreases, the amount of carbon dioxide in water decreases and the amount of carbonate formed increases.

In China, carbon dioxide flooding tests are successively developed in oil fields of Daqing, Shengli, North China, Jiangsu and the like. With CO₂Oil fields that are flooded with oil, most of which have scaling problems, are primarily secondary deposits of inorganic compounds, which are at least partially due to human factors. The scale substances are attached to the surface equipment and the pipeline wall, and the normal operation of production is seriously influenced. It should be noted that the conditions under which no two fields will scale are identical in the world, and therefore neither method can solve the scaling problem for all fields. The main cause of fouling is the change in ion concentration in the medium, which causes the changeThe main factors of the conversion are the changes in temperature, pressure and pH. In many industries, the scaling problem is significantly reduced or eliminated by removing the various ions that form the scale in various ways. However, this method is rarely used in oil fields where the water usage is high, the cost is high, and the ions in the produced water cannot be removed below the wellbore.

The microbial content of water in an oil field is high, the variety is various, carbon dioxide is adopted for oil displacement in the early stage, harmful microbes are seriously bred due to environmental change, the number of bacteria such as sulfate reducing bacteria, iron bacteria, pseudomonas and the like reaches 5 times of order of magnitude of 10, and acidification and corrosion phenomena are caused by the increase of sulfide content of biological causes, so that an inhibitor for efficiently inhibiting the acidification and corrosion of the water is urgently needed to be developed to ensure safe production. The growth process of the microorganism is a biomineralization process, calcium and magnesium ions in an extracellular polymer complex medium are deposited on the surface of a cell, the polymer serves as a cementing agent, and the scale layer can resist the penetration of a bactericide scale inhibitor, so that the three-proofing agent fails.

Chinese patent ZL201310597223.6 discloses a corrosion and scale inhibitor for inhibiting corrosion and scale formation of wells and pipes by carbon dioxide, hydrogen sulfide, etc. under high salinity, which is a multicomponent mixture composed of oxazoline derivatives, thiourea, cetylpyridinium chloride, dodecyl dimethyl benzyl ammonium chloride, aminotrimethylene phosphonic acid, hydroxy ethylidene diphosphonic acid, hexamethylenetetramine and methanol. It is suitable for high salinity, normal pressure CO₂、H₂S water environment, the using concentration is 100mg/L, and the corrosion inhibition efficiency is less than 90%.

Chinese patent ZL201410720188.7 discloses a special corrosion and scale inhibitor for oil fields, which mainly comprises zinc salt, quaternary ammonium salt, organic phosphonic acid, polyacrylic acid dispersant, auxiliary agent and water. The quaternary ammonium salt and the zinc salt are mutually dissolved by the aid of the compounded organic phosphoric acid, polyacrylic acid dispersant, ethanol or isopropanol and other assistants, so that the problem that the barium and strontium scale inhibitor is compatible with the imidazoline, which is a general corrosion inhibitor for oil fields, can be solved. However, the invention is not suitable for corrosion caused by high-temperature and high-pressure carbon dioxide, and oil wells which are treated by microorganism induction acidification such as injection system sulfate reducing bacteria, saprophytic bacteria, iron bacteria, pseudomonas and the like or by applying biotechnology at the early stage.

Disclosure of Invention

The invention aims to solve the technical problems to a certain extent, and provides a corrosion inhibitor for carbon dioxide flooding combined bacterial acidification, which can be used in oil wells with high temperature, high carbon dioxide partial pressure and rich harmful microorganisms (especially in a system with various harmful bacteria), and has the advantages of low usage amount and good effect.

The invention discloses a corrosion inhibitor for carbon dioxide flooding combined bacterial acidification, which comprises the following components:

arecoline quaternary ammonium salt 1-35 wt%

Mixed oleic acid imidazoline 1-20 wt%

1,3, 5-tris (2-hydroxyethyl) -hexahydro-s-triazine 5-15% by weight

5-10% by weight of thiourea

1-5% by weight of monoethanolamine

10-20% by weight of 2-phosphoric acid-1, 2, 4-tricarboxylic acid butane

0 to 70 weight percent of water.

In a preferred embodiment of the present invention, the arecoline quaternary ammonium salt is synthesized by the following method: adding arecoline and solvent into a reactor equipped with a condensing reflux device, dripping sodium chloroacetate at 60-100 ℃, reacting for 6-10 hours, cooling, adding the solvent, stirring, and cooling to obtain the product, namely the arecoline quaternary ammonium salt.

As a preferred embodiment of the present invention, the weight ratio of arecoline, solvent and sodium chloroacetate is 3: 2: 1; the solvent is methanol, ethanol, isopropanol, DMF, water or a mixture thereof.

As a preferred embodiment of the present invention, the mixed oleic imidazoline is synthesized by the following method: mixing the mixed oleic acid with polyethylene polyamine and hydroxy ethylenediamine, adding a dehydrating agent for reaction, wherein the acylation temperature is 160-185 ℃, the acylation time is 2-3 hours, the vacuum degree of the system is 3.55-5.93KPa, the cyclization temperature is 230-240 ℃, and the cyclization time is 4-6 hours.

In a preferred embodiment of the present invention, the dehydrating agent is toluene.

In a preferred embodiment of the invention, 0.5-3% by weight of diethylenetriamine is added in the cyclization stage of imidazoline synthesis.

The second aspect of the invention discloses a preparation method of the corrosion inhibitor for carbon dioxide flooding combined bacterial acidification, which comprises the following steps:

s1: adding arecoline quaternary ammonium salt and mixed oleic imidazoline into water according to a proportion, and uniformly mixing;

s2: then adding 1,3, 5-tri (2-hydroxyethyl) -hexahydro-s-triazine, thiourea, monoethanolamine and 2-phosphate-1, 2, 4-tricarboxylic acid butane, and uniformly mixing to obtain the product.

In a preferred embodiment of the present invention, the water temperature is controlled to be 60 ℃.

In a third aspect of the invention, the use of the corrosion inhibitor for carbon dioxide flooding and bacterial acidification for inhibiting the representative species sulfate reducing bacteria is disclosed.

As a preferred embodiment of the present invention, the inhibitor is formulated into a solution of 100 mg/L.

The invention has the beneficial effects that:

(1) the inhibitor prepared by the invention can form an effective protective film on the surface of metal, prevent the high-salinity sewage from corroding the metal under high temperature and high carbon dioxide partial pressure, and has the corrosion inhibition rate of over 94.5 percent.

(2) Has broad-spectrum inhibition effect on main strains causing water body acidification, such as sulfate reducing bacteria, saprophytic bacteria, iron bacteria, pseudomonas and the like, thereby reducing corrosion and scaling caused by microorganisms.

(3) Has better scale inhibition efficiency on carbon steel, and the scale inhibition rate is more than 93 percent.

(4) Has high absorption rate to hydrogen sulfide in sewage medium.

(5) Safe and environment-friendly, has lower use concentration and better economic benefit.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.

FIG. 1 is a graph comparing the corrosion rates before and after dosing of an oil well according to the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without any creative effort belong to the protection scope of the embodiments of the present invention.

Example 1

This example was used to prepare the corrosive medium:

adding 1.05 g sodium bicarbonate, 0.21g sodium sulfate, 1g calcium chloride, 0.05g magnesium chloride and 10g sodium chloride into 1000g water, stirring to completely dissolve to obtain CaCl₂The type oilfield simulation solution is used as a corrosion medium.

Example 2

This example was used to prepare arecoline quaternary ammonium salts:

adding arecoline and solvent into a reactor equipped with a condensing reflux device, dripping sodium chloroacetate at 75 ℃, reacting for 6-10 hours, cooling, adding the solvent, stirring, and cooling to obtain the product, namely the arecoline quaternary ammonium salt. Wherein the weight ratio of the arecoline to the solvent to the chloroacetic acid is 3: 2: 1.

example 3

This example was used to prepare mixed oleic imidazoline.

Mixing oleic acid, polyethylene polyamine and hydroxy ethylene diamine, wherein the dehydrating agent is toluene, the acylation temperature is 170 ℃, the acylation time is 2.5 hours, the vacuum degree of the system is 4.5KPa, the cyclization temperature is 235 ℃, and the cyclization time is 5 hours. In the cyclization stage of synthesizing imidazoline, an excess amount of diethylenetriamine (preferably 2% of total weight) is added, so that the yield of imidazoline is obviously increased, and under proper reaction conditions, the yield of imidazoline reaches 85%.

Example 4

This example is used to prepare the carbon dioxide flooding and bacterial acidification corrosion inhibitor provided by the present invention, and includes the following steps:

adding 20g of arecoline quaternary ammonium salt prepared in the embodiment 2 and 20g of mixed imidazoline oleate prepared in the embodiment 3 into 40g of water with the temperature of 60 ℃, adding 5g of 1,3, 5-tri (2-hydroxyethyl) -hexahydro-s-triazine, 5g of thiourea and 5g of monoethanolamine, 5g of 2-phosphate-1, 2, 4-butane tricarboxylate, and uniformly mixing to obtain the corrosion inhibitor provided by the invention.

Example 5

adding 25g of arecoline quaternary ammonium salt prepared in example 2 and 15g of mixed oleic acid imidazoline prepared in example 3 into 40g of water with the temperature of 60 ℃, uniformly stirring, 10g of 1,3, 5-tri (2-hydroxyethyl) -hexahydro-s-triazine, 5g of thiourea and 5g of monoethanolamine, and uniformly mixing to obtain the corrosion inhibitor provided by the invention.

Example 6

15g of arecoline quaternary ammonium salt prepared in the embodiment 2 and 20g of mixed oleic acid imidazoline prepared in the embodiment 3 are added into 45g of water with the temperature of 60 ℃ and stirred uniformly, 7g of 1,3, 5-tri (2-hydroxyethyl) -hexahydro-s-triazine, 5g of thiourea and 5g of monoethanolamine, 3g of 2-phosphate-1, 2, 4-tricarboxylic acid butane are mixed uniformly, and the corrosion inhibitor provided by the invention is obtained.

Example of detection

The carbon dioxide combined bacterial acidification corrosion inhibitor has the following properties:

1. determination of Corrosion inhibition

The water sample used was the water sample described in example 1 and used to determine the corrosion inhibition effect of the corrosion inhibitor provided by the present invention on high temperature and high pressure carbon dioxide. The test liquid flow rate was 1 m/s. And (4) performing weight loss analysis on the steel sheet before and after corrosion according to the oil and gas industry standard SY/T5273-2000 of the people's republic of China, and calculating the corrosion rate. The results are shown in table 1, and it can be seen from table 1 that the corrosion inhibitor provided by the present invention has good effect of controlling corrosion of carbon dioxide at high temperature and high pressure at low concentration, and the corrosion inhibition rate exceeds 94.5%.

TABLE 1 Corrosion weight loss data of test pieces under different conditions

2. Evaluation of Sterilization Effect

Examples 4-6 for determining the inhibitory effect of the corrosion inhibitor provided by the present invention on the representative species sulfate-reducing bacteria, the water sample used was the one described in example 1, and 10 was added⁵The amount of bacteria per ml was measured by a maximum possible number method and the change in the amount of bacteria before and after the test was conducted, thereby determining the inhibitory effect of the corrosion inhibitor on the microorganisms. As shown in Table 2, it can be seen from Table 2 that the concentration of the corrosion inhibitor is 50mg/L, which has a certain effect of inhibiting bacteria, and when the concentration reaches 100mg/L, the corrosion inhibitor can kill all the bacteria.

Table 2 bacterial load change before and after testing of different corrosion inhibitors at different concentrations

3. Evaluation of Scale inhibition Effect

The water sample of Jiangsu oil field is used as the sewage to be detected, and the ion components of the water sample are shown in table 3.

TABLE 3 Water sample ion composition Table

The experimental temperature for measuring the scale inhibition effect is 70 ℃, the testing time is 3 hours, and Ca is added into the water sample to be measured²⁺:HCO₃ ^-The concentration of the scale inhibitor is 100mg/L, and the concentration is 1000 mg/L. Judging the scale inhibition effect of the corrosion inhibitor on 20# steel and N80 steel in a high calcium ion environment. The results are shown in the table, and it can be seen from table 4 that the concentration is 100mg/L, the corrosion inhibitor has good scale inhibition effect on 20# steel and N80 steel, the lowest scale inhibition effect can reach 93%, the highest scale inhibition effect can reach more than 96%, and the scale inhibition effect is good.

TABLE 4 Scale inhibition Effect of Corrosion inhibitors on 20# Steel and N80 Steel in high calcium ion Environment

Application example

When the corrosion inhibitor for carbon dioxide flooding combined bacterial acidification is used, a dosing pump is adopted to drop the dosing mode through the annular space of the oil sleeve. The dosing concentration can be adjusted according to the field corrosion and scaling conditions and the oil well production dynamics, and the concentration is controlled to be 100-200 mg/L. The dosage should ensure normal and safe production of oil wells (especially a coexistence system of various harmful bacteria) with high temperature, high carbon dioxide partial pressure and rich harmful microorganisms.

Take the example of adding an acidizing corrosion inhibitor to a J-field S-block S49P1 well CO2 huff well.

The S49P1 well is a CO₂Huff and puff well, CO₂Injection time 10d, total CO injection₂The amount is 700 t. Before the test, the S49P1 well surface pipeline has certain corrosion, scaling and perforation phenomena. The concrete construction steps are as follows:

1. connecting a dosing device with the sleeve, and adding a medicament into a dosing storage tank according to requirements;

2. respectively diluting the corrosion inhibitor by 100 times in a S49P1 well dosing tank, and then adding the corrosion inhibitor from an oil sleeve annulus through a dosing pump;

3. adjusting a dosing system in time according to the on-site corrosion and scaling condition;

4. the cannula pressure must be less than the safe working pressure of the dosing pump.

The chemical concentration is 100mg/L, the chemical is added into the chemical to be a commercial corrosion inhibitor in the initial stage, the corrosion rate is reduced from 0.019mm/a to 0.005mm/a after the chemical is added, the corrosion rate is reduced to 0.003mm/a (see figure 1) after the chemical is added, the corrosion rate is far lower than 0.076mm/a of the industrial standard, in addition, compared with the common chemical, the chemical saves the cost by more than 30 percent, and better economic benefit is obtained.

Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the embodiments of the present invention, and are not limited thereto; although embodiments of the present invention have been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A corrosion inhibitor for carbon dioxide flooding combined with bacterial acidification, characterized by comprising the following components:

arecoline quaternary ammonium salt 1-35 wt%

Mixed oleic acid imidazoline 1-20 wt%

1,3, 5-tris (2-hydroxyethyl) -hexahydro-s-triazine 5-15% by weight

5-10% by weight of thiourea

1-5% by weight of monoethanolamine

10-20% by weight of 2-phosphoric acid-1, 2, 4-tricarboxylic acid butane

0 to 70 weight percent of water.

2. The inhibitor of claim 1, wherein the mixed oleic imidazoline is synthesized by: mixing the mixed oleic acid with polyethylene polyamine and hydroxy ethylenediamine, adding a dehydrating agent for reaction, wherein the acylation temperature is 160-185 ℃, the acylation time is 2-3 hours, the vacuum degree of the system is 3.55-5.93KPa, the cyclization temperature is 230-240 ℃, and the cyclization time is 4-6 hours.

3. The inhibitor according to claim 1, wherein the quaternary ammonium salt of arecoline is synthesized by: adding arecoline and solvent into a reactor equipped with a condensing reflux device, dripping sodium chloroacetate at 60-100 ℃, reacting for 6-10 hours, cooling, adding the solvent, stirring, and cooling to obtain the product, namely the arecoline quaternary ammonium salt.

4. The inhibitor according to claim 3, wherein the weight ratio of the arecoline, the solvent and the sodium chloroacetate is 3: 2: 1; the solvent is methanol, ethanol, isopropanol, DMF, water or a mixture thereof.

5. Inhibitor according to claim 2, characterized in that the dehydrating agent is toluene.

6. Inhibitor according to claim 2, characterized in that from 0.5 to 3% by weight of diethylenetriamine is added during the cyclization phase of the imidazoline synthesis.

7. The process for the preparation of the inhibitor according to any one of claims 1 to 6, characterized in that it comprises the following steps:

s1: adding arecoline quaternary ammonium salt and mixed oleic imidazoline into water according to a certain proportion, and uniformly mixing.

8. The method according to claim 7, wherein the water temperature is controlled to be 60 ℃.

9. Use of the inhibitor of any one of claims 1-6 for inhibiting the representative species sulfate-reducing bacteria.

10. The use according to claim 9, wherein the inhibitor is formulated as a 100mg/L solution.