Oil and gas well annulus organic acid salt protection liquid and preparation method and application thereof

Abstract

The invention belongs to the technical field of oil exploitation, and particularly relates to an oil and gas well annulus organic acid salt protection fluid and a preparation method and application thereof. The preparation method comprises the following steps: adding disodium lauroiminodipropionate, (3-chloro-2-hydroxypropyl) dodecyl dimethyl ammonium chloride and an organic solvent into a four-neck flask provided with a condensing tube, uniformly stirring, adjusting the pH value to be 8-9, and heating and refluxing; carrying out reduced pressure distillation on the intermediate product to obtain a viscous solid, recrystallizing and drying to obtain a protective liquid main agent; and adding the protection liquid main agent, sodium formate, 1-hydroxyethylidene-1, 1-diphosphonic acid and water into a reaction container, and uniformly stirring to obtain the product organic acid salt protection liquid. The organic acid salt protection liquid has the advantages of good corrosion and scale inhibition effects and high sterilization efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum extraction, and in particular relates to an organic acid salt protective fluid for the annular space of an oil and gas well, and a preparation method and application thereof. Background Art

[0002] In the field of oil extraction technology, oil and gas well annulus protection fluid, also known as packer fluid, plays a vital role. It is filled between the oil pipe and the oil layer casing and has two main functions: one is corrosion resistance, which can prevent the oil casing and downhole tools (such as packers and downhole safety valves) from corrosion; the other is pressure balance. The packer fluid with a certain density can balance the formation pressure, the oil pipe pressure and the casing pressure, thereby protecting the oil casing and the packer.

[0003] For production wells, the annular protection fluid will not flow without well repair; for non-production wells, it will not flow without production. Therefore, the retention time of the annular protection fluid in the casing is often very long, sometimes even for several years. Under the specific temperature and pressure downhole, the sealing fluid must remain stable for a long time without solid precipitation. When repairing or putting into production, the sealing fluid should not damage the reservoir, and should have a strong ability to protect the oil and gas layer, while maintaining good non-corrosiveness and corrosion resistance.

[0004] In order to balance the formation pressure, tubing pressure and casing pressure, the annular protection fluid needs to have a certain density. At present, the most commonly used weighting agent is formate. In order to prevent corrosion and scaling problems, it is usually necessary to add a variety of chemical additives such as corrosion inhibitors, bactericides, and scale inhibitors. The selection and ratio of these additives are crucial to the overall performance of the annular protection fluid.

[0005] CN1199430A discloses a high water content, low viscosity, oil continuous phase microemulsion and emulsion and their use in cleaning applications, and an excellent high water content, oil continuous phase microemulsion and emulsion for cleaning, containing a certain amount of water, one or more anionic surfactants from carboxylates of selected molecular weights, and one or more organic solvents, so that the composition has low conductivity and low viscosity. The microemulsion contains nitrite, which has strong oxidizing properties. If the amount used is not well controlled, it is easy to aggravate corrosion.

[0006] CN107325803B discloses an annular protection fluid for nitrogen injection wells that can inhibit oxygen corrosion and a preparation method thereof, and belongs to the technical field of oil and gas well corrosion protection. A nitrogen injection well annular protection fluid system is compounded with a corrosion inhibitor, a bactericide, a pH regulator, a deoxidizer, a density regulator and a scale inhibitor. The annular protection fluid includes the following components by mass percentage: 10-12% imidazoline corrosion inhibitor, 0.5-2.5% isothiazolinone bactericide, 3-5% alkanolamine pH regulator, 6-8% sulfite and oxime compound deoxidizer, 10-20% organic acid salt density regulator, 0.5-1.5% organic phosphonic acid scale inhibitor, and the balance is water. Under necessary conditions, an appropriate amount of anti-swelling agent should also be added. The annular protection fluid provided by the invention can well control the oxygen corrosion problem faced by the annular space of nitrogen injection wells, and at the same time has the advantages of little damage to the reservoir, strong stability, and green environmental protection. However, the addition of sulfite as a deoxidizer in this formula can easily cause the growth of sulfate-reducing bacteria, further aggravating bacterial corrosion. Summary of the invention

[0007] The present invention aims at the deficiencies of the above-mentioned prior art and provides an oil and gas well annulus organic acid salt protective liquid and its preparation method and application. The organic acid salt protective liquid of the present invention has the advantages of good corrosion and scale inhibition effects and high sterilization efficiency.

[0008] One of the purposes of the present invention is to disclose an organic acid salt protective fluid for the annulus of an oil and gas well, wherein the composition and mass components of the protective fluid are as follows: 1 part of protective liquid main agent; Sodium formate 0.5-1 part; 0.1-0.3 parts of hydroxyethylidene diphosphonic acid; 87.7-88.4 parts of water.

[0009] The molecular structure of the main agent of the protective liquid is as follows: .

[0010] Another object of the present invention is to disclose a method for preparing the organic acid salt protective solution, the specific steps are as follows: (1) Add disodium lauryl iminodipropionate, (3-chloro-2-hydroxypropyl) dodecyl dimethyl ammonium chloride and an organic solvent to a four-necked flask equipped with a condenser, stir evenly, adjust the pH to 8-9 and heat to reflux; (2) distilling the intermediate product under reduced pressure to obtain a viscous solid, recrystallizing it, and drying it to obtain a protective liquid main agent; (3) Add the protective solution main agent, sodium formate, hydroxyethylidene diphosphonic acid and water into a reaction container and stir evenly to obtain the product organic acid salt protective solution.

[0011] In the present invention, preferably, based on 1 mole part of disodium lauryl iminodipropionate, the amount of (3-chloro-2-hydroxypropyl) dodecyl dimethyl ammonium chloride is 0.8-1.2 mole parts; more preferably, based on 1 mole part of disodium lauryl iminodipropionate, the amount of (3-chloro-2-hydroxypropyl) dodecyl dimethyl ammonium chloride is 0.9-1.1 mole parts.

[0012] In the present invention, preferably, the organic solvent in step (1) is one of methanol, ethanol, propanol, isopropanol, butanol and isobutanol, and the mass ratio of the organic solvent to disodium lauryl iminodipropionate is 10-30:1.

[0013] More preferably, the organic solvent is one of ethanol or isobutanol.

[0014] In the present invention, preferably, the reflux time in step (1) is 24-72 hours.

[0015] In the present invention, preferably, the solvent for recrystallization in step (2) is one of ethyl acetate or cyclohexane.

[0016] The equation for the synthesis reaction of the main agent of the organic acid salt protective solution of the present invention is as follows: .

[0017] The third object of the present invention is to disclose the application of the organic acid salt protective fluid in the protection of oil casing in oil and water wells.

[0018] The main agent molecule in the organic acid salt protective liquid of the present invention contains a diquaternary ammonium salt, which has a positive charge and can be adsorbed on the metal surface, preventing hydrogen ions from approaching the metal surface and hindering electrons in the metal from being captured by hydrogen ions, thereby protecting the metal from being corroded by acid and having a sterilizing effect; the main agent molecule contains a carboxylic acid group, which forms a chelate film on the metal surface to protect the metal; the main agent molecule dodecyl has a hydrophobic effect and can form a hydrophobic barrier on the metal surface, so that the corrosive liquid cannot approach the metal, thereby further strengthening the corrosion inhibition effect; sodium formate is a typical weighting agent of the environmental control protective liquid, which can increase the density of the annular space protective liquid and better balance the formation pressure, the oil pipe pressure and the casing pressure; hydroxyethylidene diphosphonic acid is a typical scale inhibitor and scale preventer, which can prevent the growth of scale on the metal surface and cause crystal distortion to inhibit scale.

[0019] Compared with the prior art, the present invention has the following advantages and beneficial effects: (1) The organic acid salt protective solution of the present invention has a simple preparation method and is easy to use, and has the three-in-one functions of corrosion inhibition, sterilization, and scale inhibition; (2) The organic acid salt protective solution of the present invention has a good corrosion inhibition effect, and the corrosion inhibition rate reaches more than 92%; (3) The organic acid salt protective solution of the present invention has a good bactericidal effect, with a bactericidal rate of 100%; (4) The organic acid salt protective liquid of the present invention has a good anti-scaling effect, and the anti-scaling rate reaches more than 97%. DETAILED DESCRIPTION

[0020] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0021] Example 1 (1) Add 50 mmol of disodium lauryl iminodipropionate, 40 mmol of (3-chloro-2-hydroxypropyl) dodecyl dimethyl ammonium chloride, and 187 g of isopropanol to a four-necked flask equipped with a condenser, stir evenly, adjust the pH to 8-9, and heat under reflux for 24 h; (2) distilling the intermediate product under reduced pressure to obtain a viscous solid, recrystallizing it from ethyl acetate, and drying it to obtain a protective liquid main agent; (3) Add 10 g of the protective solution main agent, 5 g of sodium formate, 1 g of hydroxyethylidene diphosphonic acid, and 884 g of water into a reaction container and stir evenly to obtain the product organic acid salt protective solution.

[0022] Example 2 (1) Add 50 mmol of disodium lauryl iminodipropionate, 60 mmol of (3-chloro-2-hydroxypropyl) dodecyl dimethyl ammonium chloride, and 200 g of ethanol to a four-necked flask equipped with a condenser, stir evenly, adjust the pH to 8-9, and heat under reflux for 32 h; (2) distilling the intermediate product under reduced pressure to obtain a viscous solid, recrystallizing it from ethyl acetate, and drying it to obtain a protective liquid main agent; (3) Add 10 g of the protective solution main agent, 6 g of sodium formate, 2 g of hydroxyethylidene diphosphonic acid, and 882 g of water into a reaction container and stir evenly to obtain the product organic acid salt protective solution.

[0023] Example 3 (1) Add 50 mmol of disodium lauryl iminodipropionate, 42 mmol of (3-chloro-2-hydroxypropyl) dodecyl dimethyl ammonium chloride, and 280 g of propanol to a four-necked flask equipped with a condenser, stir evenly, adjust the pH to 8-9, and heat under reflux for 24 h; (2) distilling the intermediate product under reduced pressure to obtain a viscous solid, recrystallizing it from ethyl acetate, and drying it to obtain a protective liquid main agent; (3) Add 10 g of the protective solution main agent, 7 g of sodium formate, 2 g of hydroxyethylidene diphosphonic acid, and 881 g of water into a reaction container and stir evenly to obtain the product organic acid salt protective solution.

[0024] Example 4 (1) Add 50 mmol of disodium lauryl iminodipropionate, 45 mmol of (3-chloro-2-hydroxypropyl) dodecyl dimethyl ammonium chloride, and 300 g of butanol to a four-necked flask equipped with a condenser, stir evenly, adjust the pH to 8-9, and heat under reflux for 48 h; (2) distilling the intermediate product under reduced pressure to obtain a viscous solid, recrystallizing it from ethyl acetate, and drying it to obtain a protective liquid main agent; (3) Add 10 g of the protective solution main agent, 10 g of sodium formate, 1 g of hydroxyethylidene diphosphonic acid, and 879 g of water into a reaction container and stir evenly to obtain the product organic acid salt protective solution.

[0025] Example 5 (1) Add 50 mmol of disodium lauryl iminodipropionate, 48 mmol of (3-chloro-2-hydroxypropyl) dodecyl dimethyl ammonium chloride, and 402 g of propanol to a four-necked flask equipped with a condenser, stir evenly, adjust the pH to 8-9, and heat under reflux for 48 h; (2) distilling the intermediate product under reduced pressure to obtain a viscous solid, recrystallizing it from ethyl acetate, and drying it to obtain a protective liquid main agent; (3) Add 10 g of the protective solution main agent, 10 g of sodium formate, 3 g of hydroxyethylidene diphosphonic acid, and 877 g of water into a reaction container and stir evenly to obtain the product organic acid salt protective solution.

[0026] Example 6 (1) Add 50 mmol of disodium lauryl iminodipropionate, 55 mmol of (3-chloro-2-hydroxypropyl) dodecyl dimethyl ammonium chloride, and 500 g of ethanol to a four-necked flask equipped with a condenser, stir evenly, adjust the pH to 8-9, and heat under reflux for 60 h; (2) distilling the intermediate product under reduced pressure to obtain a viscous solid, recrystallizing it from ethyl acetate, and drying it to obtain a protective liquid main agent; (3) Add 10 g of the protective solution main agent, 9 g of sodium formate, 2 g of hydroxyethylidene diphosphonic acid, and 879 g of water into a reaction container and stir evenly to obtain the product organic acid salt protective solution.

[0027] Example 7 (1) Add 50 mmol of disodium lauryl iminodipropionate, 52 mmol of (3-chloro-2-hydroxypropyl) dodecyl dimethyl ammonium chloride, and 560 g of isobutyl alcohol to a four-necked flask equipped with a condenser, stir evenly, adjust the pH to 8-9, and heat under reflux for 72 h; (2) distilling the intermediate product under reduced pressure to obtain a viscous solid, recrystallizing it from cyclohexane, and drying it to obtain a protective liquid main agent; (3) Add 10 g of the protective solution main agent, 8 g of sodium formate, 3 g of hydroxyethylidene diphosphonic acid, and 879 g of water into a reaction container and stir evenly to obtain the product organic acid salt protective solution.

[0028] Example 8 (1) Add 50 mmol of disodium lauryl iminodipropionate, 51 mmol of (3-chloro-2-hydroxypropyl) dodecyl dimethyl ammonium chloride, and 464 g of ethanol to a four-necked flask equipped with a condenser, stir evenly, adjust the pH to 8-9, and heat under reflux for 72 h; (2) distilling the intermediate product under reduced pressure to obtain a viscous solid, recrystallizing it from cyclohexane, and drying it to obtain a protective liquid main agent; (3) Add 10 g of the protective solution main agent, 8 g of sodium formate, 3 g of hydroxyethylidene diphosphonic acid, and 879 g of water into a reaction container and stir evenly to obtain the product organic acid salt protective solution.

[0029] Example 9 Corrosion rate test experiment 950 ml of produced water from an oil field in a certain block was taken, 250 ml of the organic acid salt protective solution (Example 1-8) of the present invention was added, and the static corrosion rate at normal pressure was measured at 90°C using a hanging plate made of Q235, and the corrosion inhibition rate was calculated. The test method was based on the method 4.7 of SY / T5273-2014 "Performance Indicators and Evaluation Methods of Corrosion Inhibitors for Oilfield Produced Water Treatment". At the same time, produced water was used as a blank comparison. The initial corrosion rate of produced water was 0.265 mm / a, and the test period was 7d. The test results are shown in Table 1.

[0030] It can be seen from Table 1 that the corrosion inhibition rates of the organic acid salt protective solutions of the present invention (Examples 1-8) all reached over 92%, with the highest reaching 95%; the organic acid salt protective solutions of the present invention have good anti-corrosion effects.

[0031] Example 10 Evaluation of Sterilization Effect 99 ml of produced water from an oil field in a certain block was added to a series of narrow-necked bottles, and 1 ml of the present invention was added, shaken, and placed in a 60° C. oven. Samples were taken after 1 hour, and the sulfate-reducing bacteria content was detected by the three-tube MPN method. The bactericidal rate was calculated, and produced water was used as a blank comparison. The initial sulfate-reducing bacteria content of the produced water was 450 / ml. The test results are shown in Table 1.

[0032] It can be seen from Table 1 that the organic acid salt protection solutions of the present invention (Examples 1-8) all have good bactericidal effects, and the bactericidal rates all reach 100%. Therefore, no bactericide needs to be added to the annular organic acid salt protection solution.

[0033] Example 11 Evaluation of scale inhibition effect The anti-scaling rate of CaCO3 was tested with reference to the method in SY / T5673-2020 "General Technical Conditions for Anti-scaling Agents for Oil Fields", where the concentration of the solution in 8.16 was changed to 10wt%. The test results are shown in Table 1.

[0034] Table 1 Test results of corrosion inhibition, anti-scaling and sterilization sample Corrosion inhibition rate, % Sterilization rate, % Anti-scaling rate, % Example 1 92.1 100 97.1 Example 2 93.4 100 97.5 Example 3 94.5 100 98 Example 4 94.2 100 98.3 Example 5 95.0 100 98.5 Example 6 94.8 100 98.5 Example 7 95 100 98.8 Example 8 95.1 100 98.6 It can be seen from Table 1 that the scale inhibition rates of the organic acid salt protection solutions (Examples 1-8) of the present invention all reached over 97%, with the highest reaching 98.8%; the organic acid salt protection solutions of the present invention have good scale inhibition effect.

[0035] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. An organic acid salt protective fluid for annular space of oil and gas wells, characterized in that: The composition and mass components of the protective solution are as follows: 1 part of protective liquid main agent; Sodium formate 0.5-1 part; 0.1-0.3 parts of hydroxyethylidene diphosphonic acid; Water 87.7-88.4 parts; The molecular structure of the main agent of the protective liquid is as follows: 。 2. The method for preparing an organic acid salt protective liquid for annular space of oil and gas wells according to claim 1, characterized in that: The preparation method is as follows: (1) Add disodium lauryl iminodipropionate, (3-chloro-2-hydroxypropyl) dodecyl dimethyl ammonium chloride and an organic solvent to a four-necked flask equipped with a condenser, stir evenly, adjust the pH to 8-9 and heat to reflux; (2) distilling the intermediate product under reduced pressure to obtain a viscous solid, recrystallizing it, and drying it to obtain a protective liquid main agent; (3) Add the protective solution main agent, sodium formate, hydroxyethylidene diphosphonic acid and water into a reaction container and stir evenly to obtain the product organic acid salt protective solution; Based on 1 mole part of disodium lauriiminodipropionate, the amount of (3-chloro-2-hydroxypropyl) dodecyldimethylammonium chloride used is 0.8-1.2 mole parts.

3. The preparation method according to claim 2, characterized in that: Based on 1 mole part of disodium lauriiminodipropionate, the amount of (3-chloro-2-hydroxypropyl) dodecyldimethylammonium chloride used is 0.9-1.1 mole parts.

4. The preparation method according to claim 2, characterized in that: The organic solvent in step (1) is one of methanol, ethanol, propanol, isopropanol, butanol and isobutanol, and the mass ratio of the organic solvent to disodium lauryl iminodipropionate is 10-30:

1.

5. The preparation method according to claim 4, characterized in that: The organic solvent is ethanol or isobutanol.

6. The preparation method according to claim 2, characterized in that: The reflux time in step (1) is 24-72 hours.

7. The preparation method according to claim 2, characterized in that: The solvent used for recrystallization in step (2) is one of ethyl acetate or cyclohexane.

8. Use of the organic acid salt protective fluid according to claim 1 in oil and water well casing protection.

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