A neutral plug remover and a preparation method thereof

Abstract

The application discloses a kind of neutral plugging remover and preparation method thereof, the neutral plugging remover includes 25%~40% chelating agent, 5%~8% biological enzyme, 10%~20% molybdenum-containing Gemini surfactant, 3%~5% solubilizer, 1%~5% auxiliary agent, pH regulator, and the rest is water by mass percentage.The application can overcome the strong corrosion and strong irritability of strong acid, with the advantages of high scale removal efficiency, safety and environmental protection, which will not cause harm to human health and oil reservoir environment.The chelating agent in the application can react with Ca 2+ , Mg 2+ , Ba 2+ , Sr 2+ , etc. , and form stable water-soluble eutectic, thereby dissolving and corroding insoluble barite and other blockages;The molybdenum-containing Gemini surfactant can accelerate the infiltration and penetration of chelating agent on the surface of barite, thereby accelerating the dissolution of barite;The biological enzyme can decompose and degrade organic matter.

Description

Technical Field

[0001] This invention relates to the field of unblocking agents, and in particular to a neutral unblocking agent and its preparation method. Background Technology

[0002] During water injection development in oil fields, produced water is generally used for reinjection. The reinjected water has high mineralization and high sulfate ion content. The formation water also has a high content of divalent metal ions and contains a certain amount of barium and strontium ions. As the water injection cycle extends, the amount of sulfate scaling will further increase, causing formation blockage. The main components of the scale sample are: calcium magnesium carbonate 43%, calcium sulfate 15%, pyrite 20%, and barium (strontium) sulfate 8%.

[0003] Currently, oilfield unblocking primarily relies on acidizing, using hydrochloric acid, terrine acids, organic acids, polyhydrogen acids, and strong oxidizing acids. Acidizing operations bring serious safety risks and immense environmental pressure. Acids are hazardous chemicals, posing safety hazards during transportation, storage, and use; the process causes severe corrosion to equipment, surface pipelines, wellheads, and casing, resulting in high maintenance costs; acid runoff generates large amounts of residual acid that requires complex and expensive recycling; and it easily causes soil acidification, reacting with sulfide scale to produce toxic gases, causing environmental pollution. In older oilfields in China, the total number of wells treated annually exceeds 10,000, with acidizing accounting for 60% of these unblocking measures. The total volume of various acid solutions used exceeds 100,000 cubic meters, with runoff generating over 80,000 cubic meters of residual acid. Oilfield companies and engineering contractors incur significant financial costs and bear enormous safety responsibilities annually for this purpose.

[0004] Furthermore, scale types such as barium sulfate and strontium sulfate are difficult to dissolve even with acids. Currently, the most effective products for removing barium sulfate are generally highly alkaline. For example, using DTPA to effectively remove scale requires extreme conditions such as high pH (pH>11) and heating, and large amounts of alkali can pollute the environment. Summary of the Invention

[0005] To address the above problems, the present invention aims to provide a neutral unblocking agent and its preparation method.

[0006] The technical solution of the present invention is as follows:

[0007] On the one hand, a neutral unblocking agent is provided, comprising, by weight percentage, 25%–40% chelating agent, 5%–8% bio-enzyme, 10%–20% molybdenum-containing gemini surfactant, 3%–5% solubilizer, 1%–5% additives, pH adjuster, and the remainder being water.

[0008] Preferably, the chelating agent is a combination of two of sodium ethylenediaminetetraacetate, alginate, and aza-18-crown ether-6.

[0009] Preferably, the aza-18-crown ether-6 is one of macropa, macropaquin, and macroquin-SO3;

[0010] The molecular structural formula of macropa is as follows:

[0011]

[0012] The molecular structural formula of macropaquin is:

[0013]

[0014] The molecular structural formula of macroquin-SO3 is:

[0015]

[0016] Preferably, the bioenzyme is α-amylase or mannan.

[0017] Preferably, the molybdenum-containing gemini surfactant is prepared by the following steps:

[0018] S1: 100-130 parts of lactobionic acid and 25-40 parts of N,N-dimethylaminopropylamine were subjected to an amidation condensation reaction under the condition of 0.1-0.2 parts of potassium hydroxide as a catalyst. The reaction temperature was 90℃-110℃ and the reaction time was 8h-12h to obtain the intermediate tertiary amine.

[0019] S2: The intermediate tertiary amine and 35-40 parts of dichloroethyl ether are subjected to a chain-linking reaction at a temperature of 70-100°C for 10-12 hours to obtain a chain-linked tertiary amine.

[0020] S3: The tertiary amine with the chain is mixed with 110-140 parts of isopropanol and 40-50 parts of molybdenum dioxide dichloride, and reacted at 80-90°C for 4-5 hours to obtain the molybdenum-containing gemini surfactant.

[0021] Preferably, the co-solvent is one or more of ethanol, isopropanol, n-butanol, isobutanol, and n-pentanol.

[0022] Preferably, the adjuvant is one or more of nano-limonene, triglycerides, isopropyl myristate, and glyceryl esters.

[0023] On the other hand, a method for preparing the neutral unblocking agent described in any one of the above claims is also provided, comprising the following steps:

[0024] S1': Mix the chelating agent, the biological enzyme, and the molybdenum-containing gemini surfactant evenly to obtain a mixture;

[0025] S2': Water is added to the mixture at 40℃~65℃, and the mixture is stirred continuously at 1000~2000r / min for 20min~30min to obtain a mixed solution;

[0026] S3': The mixed solution is ultrasonically treated for 30 to 40 minutes, and a pH adjuster is added to adjust it to neutral to obtain the neutral unblocking agent.

[0027] The beneficial effects of this invention are:

[0028] This invention overcomes the strong corrosiveness and irritation of strong acids, offering advantages such as high descaling efficiency, safety, and environmental friendliness, without harming human health or the oil reservoir environment. The chelating agent in this invention can react with Ca in the target layer. 2+ Mg 2 + Ba 2+ 、Sr 2+ The divalent metal inorganic ions act to form a stable water-soluble eutectic, thereby dissolving insoluble blockages such as barite; the molybdenum-containing gemini surfactant, solubilizer, and auxiliaries can accelerate the wetting and penetration of the chelating agent on the barite surface, thereby accelerating the dissolution of barite; the bio-enzyme can decompose and degrade organic matter. Detailed Implementation

[0029] The present invention will be further described below with reference to embodiments. It should be noted that, unless otherwise specified, the embodiments and technical features described in this application can be combined with each other. It should also be pointed out that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. The terms "comprising" or "including" and similar words used in this invention refer to elements or objects preceding the word that encompass the elements or objects listed following the word and their equivalents, without excluding other elements or objects.

[0030] On the one hand, the present invention provides a neutral unblocking agent, which, by mass percentage, comprises 25% to 40% chelating agent, 5% to 8% bio-enzyme, 10% to 20% molybdenum-containing gemini surfactant, 3% to 5% solubilizer, 1% to 5% auxiliary agent, pH adjuster, and the remainder being water.

[0031] In the above embodiments, the chelating agent of the present invention can react with Ca in the target layer. 2+ Mg 2+ Ba 2+ 、Sr 2+The divalent metal inorganic ions act to form a stable water-soluble eutectic, thereby dissolving insoluble blockages such as barite; the molybdenum-containing gemini surfactant, solubilizer, and auxiliaries can accelerate the wetting and penetration of the chelating agent on the surface of barite, thereby accelerating the dissolution of barite; the bio-enzyme can more easily penetrate into the hard barite, making it loose and peel off, and can also accelerate the decomposition and degradation of organic matter.

[0032] In one specific embodiment, the chelating agent is a combination of two of sodium ethylenediaminetetraacetate, alginate, and aza-18-crown ether-6; the bioenzyme is α-amylase or mannan; and the molybdenum-containing gemini surfactant is prepared by the following steps:

[0033] S1: 100-130 parts of lactobionic acid and 25-40 parts of N,N-dimethylaminopropylamine were subjected to an amidation condensation reaction under the condition of 0.1-0.2 parts of potassium hydroxide as a catalyst. The reaction temperature was 90℃-110℃ and the reaction time was 8h-12h to obtain the intermediate tertiary amine.

[0034] S2: The intermediate tertiary amine and 35-40 parts of dichloroethyl ether are subjected to a chain-linking reaction at a temperature of 70-100°C for 10-12 hours to obtain a chain-linked tertiary amine.

[0035] S3: The tertiary amine with the chain is mixed with 110-140 parts of isopropanol and 40-50 parts of molybdenum dioxide dichloride, and reacted at 80-90°C for 4-5 hours to obtain the molybdenum-containing gemini surfactant.

[0036] It should be noted that the above embodiments are merely one method for preparing the molybdenum-containing gemini surfactant of the present invention. The catalyst, solvent, etc., can be adjusted as needed. When a certain reagent is adjusted, the corresponding reaction parameters need to be adjusted accordingly. Furthermore, those skilled in the art can obtain the molybdenum-containing gemini surfactant according to the above preparation method of the present invention, thereby analyzing and obtaining the structure of the molybdenum-containing gemini surfactant, and then, based on the structure of the molybdenum-containing gemini surfactant, can use other preparation methods to prepare the molybdenum-containing gemini surfactant.

[0037] In one specific embodiment, the aza-18-crown ether-6 is one of macropa, macropaquin, and macroquin-SO3; wherein, the molecular structural formula of macropa is:

[0038]

[0039] The molecular structural formula of macropaquin is:

[0040]

[0041] The molecular structural formula of macroquin-SO3 is:

[0042]

[0043] In one specific embodiment, the co-solvent is one or more of ethanol, isopropanol, n-butanol, isobutanol, and n-pentanol.

[0044] In one specific embodiment, the adjuvant is one or more of nano-limonene, triglycerides, isopropyl myristate, and glyceryl esters.

[0045] On the other hand, the present invention also provides a method for preparing the neutral unblocking agent according to any one of the above claims, comprising the following steps:

[0046] S1': Mix the chelating agent, the biological enzyme, and the molybdenum-containing gemini surfactant evenly to obtain a mixture;

[0047] S2': Water is added to the mixture at 40℃~65℃, and the mixture is stirred continuously at 1000~2000r / min for 20min~30min to obtain a mixed solution;

[0048] S3': The mixed solution is ultrasonically treated for 30 to 40 minutes, and a pH adjuster is added to adjust it to neutral to obtain the neutral unblocking agent.

[0049] Example 1

[0050] A neutral unblocking agent is prepared by the following steps: 30% chelating agent, 8% bio-enzyme, 14% molybdenum-containing gemini surfactant, 3.5% isopropanol, and 1% triglyceride are added to a stirrer and mixed evenly. The temperature inside the stirrer is maintained at 60°C. Then water is added, and the mixture is continuously stirred at 1000 r / min for 25 min. The mixture is then ultrasonically treated for 30 min. Finally, KOH is added to adjust the pH to 7.4 to obtain the neutral unblocking agent.

[0051] In this embodiment, the chelating agent consists of 10% sodium ethylenediaminetetraacetate and 20% macropa, the bioenzyme is mannan, and the molybdenum-containing gemini surfactant is prepared using the following steps:

[0052] (1) Add 115 g of lactobionic acid and 40 g of N,N-dimethylaminopropylamine to a container with a reflux condenser and carry out an amidation condensation reaction. Add 0.2 g of potassium hydroxide as a catalyst. The reaction temperature is 100 °C. Stir and reflux for 10 h to obtain the intermediate product tertiary amine.

[0053] (2) Add 40 g of dichloroethyl ether to the intermediate tertiary amine to carry out a chain-linking reaction at a reaction temperature of 100°C and stir under reflux for 11 h to obtain a chain-linked tertiary amine.

[0054] (3) Add the tertiary amine and 115 g of isopropanol to a container, add 45 g of molybdenum dioxide, stir and reflux at 80°C for 5 h to obtain a yellow viscous liquid, which is the molybdenum-containing twin surfactant, wherein the mass percentage of the active ingredient multibranched twin amphoteric surfactant is 60%.

[0055] Example 2

[0056] A neutral unblocking agent is prepared by the following steps: 30% chelating agent, 6% bio-enzyme, 16% molybdenum-containing gemini surfactant, 4% isobutanol, and 3% isopropyl myristate are added to a stirrer and mixed evenly. The temperature inside the stirrer is maintained at 50°C. Then water is added, and the mixture is continuously stirred at 1500 r / min for 30 min. The mixture is then ultrasonically treated for 35 min. Finally, KOH is added to adjust the pH to 8 to obtain the neutral unblocking agent.

[0057] In this embodiment, the chelating agent is composed of 12% sodium ethylenediaminetetraacetate and 18% alginate, the bioenzyme is mannan, and the molybdenum-containing gemini surfactant is the same as in Example 1.

[0058] Example 3

[0059] A neutral unblocking agent is prepared by the following steps: 35% chelating agent, 8% bio-enzyme, 18% molybdenum-containing gemini surfactant, 5% isopropanol, and 4.3% nano-modified limonene are added to a stirrer and mixed evenly. The temperature inside the stirrer is maintained at 40°C. Then water is added, and the mixture is continuously stirred at 2000 r / min for 30 min. The mixture is then ultrasonically treated for 40 min. Finally, KOH is added to adjust the pH to 7 to obtain the neutral unblocking agent.

[0060] In this embodiment, the chelating agent is composed of 10% sodium ethylenediaminetetraacetate and 25% macropaquin, the biological enzyme is α-amylase, and the molybdenum-containing gemini surfactant is the same as in Example 1.

[0061] Comparative Example 1

[0062] Unlike Example 1, the chelating agent added in this comparative example is sodium ethylenediaminetetraacetate alone.

[0063] Comparative Example 2

[0064] Unlike Example 1, the surfactant added in this comparative example is sodium dodecyl sulfate.

[0065] Comparative Example 3

[0066] Unlike Example 1, the surfactant added in this comparative example is Gemini surfactant GS-A6 (Qingdao Tengyun Chemical Technology Co., Ltd.).

[0067] Comparative Example 4

[0068] Unlike Example 1, the surfactant added in this comparative example is the multibranched twinned amphoteric surfactant from "Research and Application of High Temperature Slow-Acting Environmentally Friendly Acid".

[0069] Comparative Example 5

[0070] Unlike Example 1, no biological enzymes were added to this comparative example.

[0071] The neutral unblocking agents of Example 1 and each comparative example were tested for scale dissolution in reservoir conditions at 60°C, the neutral unblocking agent of Example 2 was tested at 50°C, and the neutral unblocking agent of Example 3 was tested at 40°C. The results are shown in Table 1.

[0072] Table 1. Scale Dissolution Rate Test Results of Neutral Unblocking Agent

[0073]

[0074] As shown in Table 1, the present invention exhibits excellent scale dissolution effects under low-temperature reservoir conditions. The scale dissolution rates for calcium carbonate at 6h and 12h are greater than 50.5% and 69.9%, respectively; for calcium sulfate at 6h and 12h, respectively, respectively, respectively; for barium sulfate at 6h and 12h, respectively, respectively, respectively, respectively; and for mixed scale samples at 6h and 12h, respectively, respectively, respectively, respectively, respectively, respectively, are greater than 47.7% and 65.3%.

[0075] Based on the scale dissolution rate test results of Example 1 and each comparative example in Table 1, the improvement effect of the scale dissolution rate of the present invention compared with each comparative example is calculated, and the results are shown in Table 2:

[0076] Table 2. Scale dissolution rate improvement effect of the present invention

[0077]

[0078]

[0079] As shown in Table 2, the chelating agent mixture significantly improved the scale-dissolving effect compared to a single chelating agent, especially for barium sulfate, where the scale-dissolving rate increased by 187.97% at 6 hours and by 225.12% at 12 hours. The surfactant using molybdenum-containing gemini surfactants significantly improved the scale-dissolving effect compared to conventional anionic surfactants, especially for barium sulfate, where the scale-dissolving rate increased by 110.65% at 6 hours and by 121.38% at 12 hours. The surfactant using molybdenum-containing gemini surfactants also significantly improved the scale-dissolving effect compared to other gemini surfactants. Compared to neutral unblocking agents without bio-enzymes, this invention improved the scale-dissolving effect of mixed scale samples by 93.81% at 6 hours and 87.91% at 12 hours, indicating that bio-enzymes can promote the decomposition of scale samples, especially organic matter and other substances in mixed scale samples.

[0080] In summary, the neutral unblocking agent of this invention can overcome the strong corrosiveness and irritation of strong acids, and has the advantage of high descaling efficiency. Compared with the prior art, this invention represents a significant advancement.

[0081] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A neutral plug remover, characterized in that, The chelating agent is a combination of sodium ethylenediaminetetraacetate and azide 18-crown ether-6 or a combination of sodium ethylenediaminetetraacetate and alginate, and the azide 18-crown ether-6 is one of macropa, macropaquin and macroquin-SO3. The molecular structural formula of macropa is as follows: （Ⅰ） The molecular structural formula of macropaquin is as follows: （Ⅱ） The molecular structural formula of macroquin-SO3 is as follows: （Ⅲ）。 2. The neutral plug remover according to claim 1, wherein The biological enzyme is alpha amylase or mannan.

3. The neutral plug remover according to claim 1, wherein The molybdenum-containing gemini surfactant is prepared by the following steps: S1: amide condensation reaction of 100-130 parts of lactobionic acid and 25-40 parts of N,N-dimethylaminopropylamine in the presence of 0.1-0.2 parts of potassium hydroxide as a catalyst, the reaction temperature is 90-110 DEG C, and the reaction time is 8-12 hours to obtain an intermediate product, tertiary amine; S2: clastic reaction of the intermediate product, tertiary amine, and 35-40 parts of dichloroether, the reaction temperature is 70-100 DEG C, and the reaction time is 10-12 hours to obtain a clastic tertiary amine; S3: mixing of the clastic tertiary amine with 110-140 parts of isopropyl alcohol and 40-50 parts of dichloromolybdenum dioxide, and reaction at 80-90 DEG C for 4-5 hours to obtain the molybdenum-containing gemini surfactant.

4. The neutral plug remover according to any one of claims 1 to 3, wherein The dissolution promoter is one or more of ethanol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol and n-pentyl alcohol.

5. The neutral plug remover according to any one of claims 1 to 3, wherein The auxiliary agent is one or more of nanometer limonene, triglyceride and isopropyl myristate.

6. The neutral plug remover according to claim 4, wherein The auxiliary agent is one or more of nanometer limonene, triglyceride and isopropyl myristate.

7. A process for the preparation of the neutral plug remover as claimed in any one of claims 1 to 6, characterized in that, The following steps are included: S1': mixing of the chelating agent, biological enzyme and molybdenum-containing gemini surfactant to obtain a mixture; S2': adding water to the mixture at 40-65 DEG C, and continuously stirring at a rotation speed of 1000-2000 r / min for 20-30 minutes to obtain a mixed solution; S3': ultrasonic treatment of the mixed solution for 30-40 minutes, and adding a pH regulator to adjust to neutral to obtain the neutral plug removal agent.

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