Oil field annulus protection fluid as well as synthesis method and application thereof

Abstract

The invention belongs to the technical field of oil exploitation, and particularly relates to an oil field annulus protection fluid and a synthesis method and application thereof. The synthesis method comprises the following steps: sequentially adding cyanuric chloride and water into a reactor, stirring, cooling to below 5 DEG C, adding iminodi (methyl phosphoric acid), and maintaining the pH value to be 6-7; adding 2-naphthylamine-3, 6, 8-trisulfonic acid into the reactor, slowly stirring and heating, maintaining the pH value to be 6-7, and continuously stirring; adding 4, 6-dichloro-2-aminophenol into the reactor, slowly stirring and heating, maintaining the pH value to be 7-8, and continuously stirring; and adjusting the pH to 2-3, carrying out reduced pressure distillation, cooling, crystallizing and filtering to obtain a solid, and drying overnight to obtain the product annulus protection liquid. The corrosion inhibitor has good corrosion prevention, corrosion inhibition and sterilization effects.

Description

Technical Field

[0001] The invention belongs to the technical field of oil production, and in particular relates to an oilfield annular space protection fluid and a synthesis method and application thereof. Background Art

[0002] The corrosion of the injection and production string is a major hidden danger in the operation of the injection and production well. In order to extend the life of the injection and production well, balance the upper and lower pressures of the packer and ensure the stable operation of the packer, after the injection and production string is lowered into the production casing and the packer is set, a protective medium, namely annular protection fluid, should be added to the annulus of the oil casing.

[0003] Annulus protection fluid is the fluid filled between the oil pipe and the oil layer casing. The mechanism of action of the annulus protection fluid is to reduce the reservoir pressure borne by the casing head or the packer; reduce the pressure difference between the oil pipe and the annulus; inhibit the corrosion tendency of the oil pipe and casing, and protect the downhole tubing.

[0004] Since annular metal corrosion and sulfate-reducing bacteria are common hazards, and if completion string leakage occurs in high-sulfur gas wells, hydrogen sulfide and carbon dioxide in natural gas may enter the annular space and dissolve in the annular protection fluid, making the corrosion environment extremely harsh. Therefore, it is necessary to select an annular protection system that is corrosion-resistant and temperature-resistant and suitable for high-acid gas reservoirs, which can control corrosion on the outer wall of the oil pipe and the inner wall of the casing and inhibit the growth of sulfate-reducing bacteria during the normal production of the gas well, ensuring the long-term safe use of the oil casing.

[0005] CN107603579A discloses a low-cost oil-based annulus protection fluid suitable for CO2 flooding injection wells and a preparation method thereof, belonging to the technical field of oil and gas well corrosion protection. An oil-based annulus protection fluid system suitable for CO2 flooding injection wells is prepared by using engine oil, corrosion inhibitor, bactericide, deoxidizer, density regulator and surfactant. The annulus protection fluid comprises the following components calculated by mass percentage: 1% to 3% morpholine derivative composite corrosion inhibitor, 0.8% to 1.6% halogenated hydantoin bactericide, 3% to 5% deoxidizer, 5% to 30% organic acid salt density regulator and 3% to 5% non-ionic polyoxyethylene surfactant, and the balance is engine oil. The oil-based annulus protection fluid provided by the invention has a good protective effect on the wellbore tubing of the CO2 injection well, has good high temperature stability, good low temperature antifreeze and long-term stability, and at the same time, due to the use of refrigeration oil as a dispersant, it has the advantages of low cost and the like. However, the bactericidal performance of the invention is only about 90%. As time goes by, the remaining sulfate-reducing bacteria will gradually adapt to the environment, leading to further bacterial 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 comprises 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 formula of the invention contains sodium sulfite, which can reduce oxygen corrosion, but the generated sulfate will further promote the growth of sulfate-reducing bacteria and aggravate bacterial corrosion. Summary of the invention

[0007] The present invention aims to provide an oil and gas well annulus protection fluid and a preparation method thereof in view of the deficiencies of the above-mentioned prior art. The present invention has good anti-corrosion, corrosion inhibition and sterilization effects. The present invention does not have the ability to adjust the specific gravity of the annulus protection fluid. When used, conventional substances for adjusting the specific gravity can be added and mixed with water as needed, such as potassium formate and sodium formate. The present invention focuses on the anti-corrosion, corrosion inhibition and sterilization effects.

[0008] One of the purposes of the present invention is to disclose a method for synthesizing annular space protection fluid in oil fields, and the specific steps are as follows:

[0009] (1) Add cyanuric chloride and water to a reactor in sequence, stir to make a slurry, cool it to below 5° C. with ice water, add iminobis(methylphosphonic acid), slowly dropwise add sodium hydroxide solution, control the temperature below 10° C., and maintain the pH at 6-7 without changing;

[0010] (2) Add 2-naphthylamine-3,6,8-trisulfonic acid to the above reactor, slowly stir and heat to 30-40° C., and simultaneously dropwise add sodium hydroxide solution, maintain the pH at 6-7 and continue stirring for 50-70 min;

[0011] (3) Add 4,6-dichloro-2-aminophenol to the above reactor, slowly stir and heat to 70-80° C., and simultaneously dropwise add sodium hydroxide solution to maintain the pH at 7-8. After the dropwise addition is complete, continue stirring for 100-150 minutes;

[0012] (4) The mixed solution was adjusted to pH 2-3 with hydrochloric acid, and distilled under reduced pressure until the residual weight was 1 / 3-1 / 2 of the total weight, cooled and crystallized, filtered to obtain a solid, and dried at 80-90° C. overnight to obtain the product annular protection solution.

[0013] In the present invention, preferably, based on 1 mole of cyanuric chloride, the amounts of iminobis(methylphosphonic acid), 2-naphthylamine-3,6,8-trisulfonic acid and 4,6-dichloro-2-aminophenol are 0.8-1.2 mole, 0.8-1.2 mole and 0.8-1.2 mole, respectively.

[0014] In the present invention, preferably, the mass ratio of the water to cyanuric chloride in step (1) is 25-30:1.

[0015] The synthetic reaction equation of the oil field annular space protection fluid of the present invention is as follows:

[0016]

[0017] Another object of the present invention is to disclose an annular space protection liquid prepared by the above preparation method, wherein the molecular structure of the annular space protection liquid is as follows:

[0018]

[0019] The third object of the present invention is to disclose the application of the annulus protection fluid in the corrosion protection of injection and production wells in oil fields.

[0020] The oilfield annular space protection fluid of the present invention is synthesized by acylation of cyanuric chloride and monomers with different functions. Among them, multiple sulfonic acid groups can play a corrosion inhibition role, and multiple phosphoric acid groups can strengthen the corrosion inhibition role; multiple phosphoric acid groups can play a scale inhibition role, and multiple sulfonic acid groups can strengthen the scale inhibition role; chlorophenol groups can play a bactericidal role; cyanuric chloride itself has a corrosion inhibition and scale inhibition role.

[0021] The present invention is a multifunctional product with the following advantages and beneficial effects:

[0022] (1) The oil and gas well annulus protection fluid of the present invention has a good anti-corrosion effect. When the concentration is 1 wt % at 90° C., the static corrosion inhibition rate at normal pressure reaches more than 93%;

[0023] (2) The oil and gas well annulus protection fluid of the present invention has a good scale inhibition effect, and the scale prevention rate reaches 92% or more;

[0024] (3) The oil and gas well annulus protection fluid of the present invention has a good bactericidal effect. When the concentration is 1 wt % at 65° C., the bactericidal rate is 100%. DETAILED DESCRIPTION

[0025] 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.

[0026] The technical solution of the present invention is further described below in conjunction with specific embodiments:

[0027] Embodiment 1:

[0028] (1) 0.05 mol of cyanuric chloride and 231 g of water were added to a reactor in sequence, stirred to form a slurry, cooled to below 5° C. with ice water, 0.04 mol of iminobis(methylphosphonic acid) was added, and sodium hydroxide solution was slowly added dropwise, the temperature was controlled below 10° C., and the pH was maintained at 6-7 without any change;

[0029] (2) Add 0.05 mol of 2-naphthylamine-3,6,8-trisulfonic acid to the above reactor, slowly stir and heat to 30° C., and simultaneously dropwise add sodium hydroxide solution, maintain the pH at 6-7 and continue stirring for 60 min;

[0030] (3) Add 0.06 mol of 4,6-dichloro-2-aminophenol to the above reactor, slowly stir and heat to 70°C, and simultaneously dropwise add sodium hydroxide solution to maintain the pH at 7-8. After the dropwise addition is complete, continue stirring for 120 min;

[0031] (4) The pH of the mixed solution was adjusted to 2-3 with hydrochloric acid, and the mixture was distilled under reduced pressure until the residual weight was 1 / 2 of the total weight. The mixture was cooled and crystallized, filtered, and a solid was obtained. The solid was dried at 80° C. overnight to obtain the product annular protection solution.

[0032] Embodiment 2:

[0033] (1) 0.05 mol of cyanuric chloride and 240 g of water were added to a reactor in sequence, stirred to form a slurry, cooled to below 5° C. with ice water, 0.043 mol of iminobis(methylphosphonic acid) was added, and sodium hydroxide solution was slowly added dropwise, the temperature was controlled below 10° C., and the pH was maintained at 6-7 without any change;

[0034] (2) Add 0.055 mol of 2-naphthylamine-3,6,8-trisulfonic acid to the above reactor, slowly stir and heat to 40° C., while adding dropwise sodium hydroxide solution, maintain the pH at 6-7 and continue stirring for 50 min;

[0035] (3) Add 0.055 mol of 4,6-dichloro-2-aminophenol to the above reactor, slowly stir and heat to 80°C, and simultaneously dropwise add sodium hydroxide solution to maintain the pH at 7-8. After the dropwise addition is complete, continue stirring for 100 min;

[0036] (4) The pH of the mixed solution was adjusted to 2-3 with hydrochloric acid, and the mixture was distilled under reduced pressure until the residual weight was 1 / 2 of the total weight. The mixture was cooled and crystallized, filtered, and a solid was obtained. The solid was dried at 80° C. overnight to obtain the product annular protection solution.

[0037] Embodiment 3:

[0038] (1) 0.05 mol of cyanuric chloride and 250 g of water were added to a reactor in sequence, stirred to form a slurry, cooled to below 5° C. with ice water, 0.045 mol of iminobis(methylphosphonic acid) was added, and sodium hydroxide solution was slowly added dropwise, the temperature was controlled below 10° C., and the pH was maintained at 6-7 without any change;

[0039] (2) Add 0.06 mol of 2-naphthylamine-3,6,8-trisulfonic acid to the above reactor, slowly stir and heat to 35° C., and simultaneously dropwise add sodium hydroxide solution, maintain the pH at 6-7 and continue stirring for 70 min;

[0040] (3) Add 0.04 mol of 4,6-dichloro-2-aminophenol to the above reactor, slowly stir and heat to 72°C, and simultaneously dropwise add sodium hydroxide solution to maintain the pH at 7-8. After the dropwise addition is complete, continue stirring for 110 min;

[0041] (4) The pH of the mixed solution was adjusted to 2-3 with hydrochloric acid, and the mixture was distilled under reduced pressure until the residual weight was 1 / 3 of the total weight. The mixture was cooled and crystallized, filtered, and a solid was obtained. The solid was dried at 80° C. overnight to obtain the product annular protection solution.

[0042] Embodiment 4:

[0043] (1) 0.05 mol of cyanuric chloride and 255 g of water were added to a reactor in sequence, stirred to form a slurry, cooled to below 5° C. with ice water, 0.05 mol of iminobis(methylphosphonic acid) was added, and sodium hydroxide solution was slowly added dropwise, the temperature was controlled below 10° C., and the pH was maintained at 6-7 without any change;

[0044] (2) Add 0.04 mol of 2-naphthylamine-3,6,8-trisulfonic acid to the above reactor, slowly stir and heat to 38° C., and simultaneously dropwise add sodium hydroxide solution, maintain the pH at 6-7 and continue stirring for 60 min;

[0045] (3) Add 0.058 mol of 4,6-dichloro-2-aminophenol to the above reactor, slowly stir and heat to 80°C, and simultaneously dropwise add sodium hydroxide solution to maintain the pH at 7-8. After the dropwise addition is complete, continue stirring for 120 min;

[0046] (4) The pH of the mixed solution was adjusted to 2-3 with hydrochloric acid, and the mixture was distilled under reduced pressure until the residual weight was 1 / 2 of the total weight. The mixture was cooled and crystallized, filtered, and a solid was obtained. The solid was dried at 80° C. overnight to obtain the product annular protection solution.

[0047] Embodiment 5:

[0048] (1) 0.05 mol of cyanuric chloride and 260 g of water were added to a reactor in sequence, stirred to form a slurry, cooled to below 5° C. with ice water, 0.052 mol of iminobis(methylphosphonic acid) was added, and sodium hydroxide solution was slowly added dropwise, the temperature was controlled below 10° C., and the pH was maintained at 6-7 without any change;

[0049] (2) Add 0.044 mol of 2-naphthylamine-3,6,8-trisulfonic acid to the above reactor, slowly stir and heat to 35° C., while adding dropwise sodium hydroxide solution, maintain the pH at 6-7 and continue stirring for 65 min;

[0050] (3) Add 0.058 mol of 4,6-dichloro-2-aminophenol to the above reactor, slowly stir and heat to 75°C, and simultaneously dropwise add sodium hydroxide solution to maintain the pH at 7-8. After the dropwise addition is complete, continue stirring for 120 min;

[0051] (4) The pH of the mixed solution was adjusted to 2-3 with hydrochloric acid, and the mixture was distilled under reduced pressure until the residual weight was 1 / 3 of the total weight. The mixture was cooled and crystallized, filtered, and a solid was obtained. The solid was dried at 80° C. overnight to obtain the product annular protection solution.

[0052] Embodiment 6:

[0053] (1) 0.05 mol of cyanuric chloride and 265 g of water were added to a reactor in sequence, stirred to form a slurry, cooled to below 5° C. with ice water, 0.055 mol of iminobis(methylphosphonic acid) was added, and sodium hydroxide solution was slowly added dropwise, the temperature was controlled below 10° C., and the pH was maintained at 6-7 without any change;

[0054] (2) Add 0.05 mol of 2-naphthylamine-3,6,8-trisulfonic acid to the above reactor, slowly stir and heat to 30° C., and simultaneously dropwise add sodium hydroxide solution, maintain the pH at 6-7 and continue stirring for 55 min;

[0055] (3) Add 0.045 mol of 4,6-dichloro-2-aminophenol to the above reactor, slowly stir and heat to 80°C, and simultaneously dropwise add sodium hydroxide solution to maintain the pH at 7-8. After the dropwise addition is complete, continue stirring for 150 minutes;

[0056] (4) The pH of the mixed solution was adjusted to 2-3 with hydrochloric acid, and the mixture was distilled under reduced pressure until the residual weight was 1 / 2 of the total weight. The mixture was cooled and crystallized, filtered, and a solid was obtained. The solid was dried at 80° C. overnight to obtain the product annular protection solution.

[0057] Embodiment 7:

[0058] (1) 0.05 mol of cyanuric chloride and 270 g of water were added to a reactor in sequence, stirred to form a slurry, cooled to below 5° C. with ice water, 0.058 mol of iminobis(methylphosphonic acid) was added, and sodium hydroxide solution was slowly added dropwise, the temperature was controlled below 10° C., and the pH was maintained at 6-7 without any change;

[0059] (2) Add 0.052 mol of 2-naphthylamine-3,6,8-trisulfonic acid to the above reactor, slowly stir and heat to 35° C., while adding dropwise sodium hydroxide solution, maintain the pH at 6-7 and continue stirring for 50 min;

[0060] (3) Add 0.05 mol of 4,6-dichloro-2-aminophenol to the above reactor, slowly stir and heat to 72°C, and simultaneously dropwise add sodium hydroxide solution to maintain the pH at 7-8. After the dropwise addition is complete, continue stirring for 130 min;

[0061] (4) The pH of the mixed solution was adjusted to 2-3 with hydrochloric acid, and the mixture was distilled under reduced pressure until the residual weight was 1 / 3 of the total weight. The mixture was cooled and crystallized, filtered, and a solid was obtained. The solid was dried at 80° C. overnight to obtain the product annular protection solution.

[0062] Example 8

[0063] (1) 0.05 mol of cyanuric chloride and 276 g of water were added to a reactor in sequence, stirred to form a slurry, cooled to below 5° C. with ice water, 0.06 mol of iminobis(methylphosphonic acid) was added, and sodium hydroxide solution was slowly added dropwise, the temperature was controlled below 10° C., and the pH was maintained at 6-7 without any change;

[0064] (2) Add 0.048 mol of 2-naphthylamine-3,6,8-trisulfonic acid to the above reactor, slowly stir and heat to 33° C., while adding dropwise sodium hydroxide solution, and continue stirring for 70 min after the pH value is maintained at 6-7 without any change;

[0065] (3) Add 0.048 mol of 4,6-dichloro-2-aminophenol to the above reactor, slowly stir and heat to 78°C, and simultaneously dropwise add sodium hydroxide solution to maintain the pH at 7-8. After the dropwise addition is complete, continue stirring for 140 min;

[0066] (4) The pH of the mixed solution was adjusted to 2-3 with hydrochloric acid, and the mixture was distilled under reduced pressure until the residual weight was 1 / 2 of the total weight. The mixture was cooled and crystallized, filtered, and a solid was obtained. The solid was dried at 80° C. overnight to obtain the product annular protection solution.

[0067] Example 9 Corrosion Rate Test

[0068] 100 ml of water after oil-water separation of Shengli Oilfield oil well produced fluid and 1 g of the annular space protection fluid (Example 1-8) of the present invention were mixed evenly, and the static corrosion rate at normal pressure was measured at 90°C. The test was performed with reference to SY / T 5273-2014 "Performance Indicators and Evaluation Methods for Corrosion Inhibitors for Oilfield Produced Water Treatment". The test results are shown in Table 1.

[0069] From Table 1 we can see that:

[0070] The annulus protection fluid of the present invention (Examples 1-8) has a static corrosion inhibition rate of more than 92% at normal pressure when used at a concentration of 1wt% at 90°C, with the highest reaching 94.8% (Example 2, Example 7). The annulus protection fluid of the present invention has a good anti-corrosion effect.

[0071] Example 10 Evaluation of scale inhibition effect

[0072] The anti-scaling rate of CaCO3 of the annular space protection fluid (Examples 1-8) of the present invention was tested with reference to the method in SY / T5673-2020 "General Technical Conditions for Anti-scaling Agents for Oil Fields", and the test results are shown in Table 1.

[0073] From Table 1 we can see that:

[0074] The annulus protection liquid of the present invention (Examples 1-8) has a scale prevention rate of 92% or more, and the highest is 94% (Examples 7 and 8). The annulus protection liquid of the present invention has a good scale prevention effect.

[0075] Example 11 Evaluation of Sterilization Effect

[0076] Take 100 ml of water after oil-water separation of Shengli Oilfield oil well production fluid, 1 g of the present invention, mix them evenly, put them in a 65° C. oven, take samples after 30 minutes, use MPN method to detect sulfate-reducing bacteria content, calculate the sterilization rate, and the test results are shown in Table 1.

[0077] Table 1 Test results of corrosion inhibition, anti-scaling and sterilization

[0078] sample Corrosion inhibition rate, % Anti-scaling rate, % Sterilization rate, % Example 1 93.9 92 100 Example 2 94.8 92.6 100 Example 3 95 93.1 100 Example 4 92.3 93.4 100 Example 5 92.8 93.7 100 Example 6 93.3 93.8 100 Example 7 94.8 94 100 Example 8 94.4 94 100

[0079] From Table 1 we can see that:

[0080] The annulus protection liquid of the present invention (Examples 1-8) has a sterilization rate of 100% when the concentration is 1 wt% at 65°C. The annulus protection liquid of the present invention has a good sterilization effect.

[0081] 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. A method for synthesizing annular space protection fluid in oil fields, characterized in that: The specific steps of the synthetic method are as follows: (1) Add cyanuric chloride and water to a reactor in sequence, stir to make a slurry, cool it to below 5° C. with ice water, add iminobis(methylphosphonic acid), slowly dropwise add sodium hydroxide solution, control the temperature below 10° C., and maintain the pH at 6-7 without changing; (2) Add 2-naphthylamine-3,6,8-trisulfonic acid to the above reactor, slowly stir and heat to 30-40° C., and simultaneously dropwise add sodium hydroxide solution, maintain the pH at 6-7 and continue stirring for 50-70 min; (3) Add 4,6-dichloro-2-aminophenol to the above reactor, slowly stir and heat to 70-80° C., and simultaneously dropwise add sodium hydroxide solution to maintain the pH at 7-8. After the dropwise addition is complete, continue stirring for 100-150 minutes; (4) The mixed solution was adjusted to pH 2-3 with hydrochloric acid, and distilled under reduced pressure until the residual weight was 1 / 3-1 / 2 of the total weight, cooled and crystallized, filtered to obtain a solid, and dried at 80-90° C. overnight to obtain the product annular protection solution.

2. The synthesis method according to claim 1, characterized in that: Based on 1 mole of cyanuric chloride, the amounts of iminobis(methylphosphonic acid), 2-naphthylamine-3,6,8-trisulfonic acid and 4,6-dichloro-2-aminophenol are 0.8-1.2 mole, 0.8-1.2 mole and 0.8-1.2 mole respectively.

3. The synthesis method according to claim 1, characterized in that: The mass ratio of the water to cyanuric chloride in step (1) is 25-30:

1.

4. The annular space protection liquid prepared by the synthesis method according to any one of claims 1 to 3, characterized in that: The molecular structure of the annular space protection liquid is as follows:

5. Application of the annulus protection fluid according to claim 4 in corrosion protection of injection and production wells in oil fields.

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