Chelating blocking remover for oil field and preparation method of chelating blocking remover

Abstract

The invention belongs to the technical field of blocking remover preparation, and particularly relates to a chelating blocking remover for an oil field and a preparation method of the chelating blocking remover. According to the chelating blocking remover for the oil field, calcium ions and magnesium ions are removed through the synergistic effect of 1, 2-bis (2-aminophenoxy)-ethane-N, N, N ', N'-tetraacetic acid and the nitrilotriacetic acid disodium salt, aluminum ions and iron ions are removed through the synergistic effect of 1, 2-dimethyl-3-hydroxy-4-pyridone and the N, N '-ethylenediamine disuccinic acid, and the chelating blocking remover for the oil field has the advantages that the chelating blocking remover for the oil field is environmentally friendly and free of pollution. According to the present invention, potassium dihydrogen phosphate is adopted as a stabilizer, and polyoxyethylene lauryl ether sodium sulfate and sodium ricinoleate are added so as to improve the mixed scale removing effect by changing the rock surface wettability, promoting crude oil stripping and interacting with other raw materials. Due to the synergistic effect of the raw materials, the prepared chelating agent for the oil field has a very good corrosion rate on inorganic scales.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of plugging removers, and specifically relates to a chelating plugging remover for oil fields and a preparation method thereof. Background Art

[0002] During oilfield development, factors such as increased formation pressure and temperature, incompatibility between injected water and external fluids, and the accumulation of bacterial metabolites can cause blockages with inorganic salts, iron compounds, biological slime, and polymers, hindering effective production. This is especially true for oilfields in the mid- and late-stage development stages, where oil and water become increasingly complex and wellbore conditions deteriorate, leading to increasingly severe blockages.

[0003] The main reasons for the blockage of polymer injection wells include the following aspects: (1) During the injection process, polymers will be retained in the rock core due to adsorption and capture, reducing the rock permeability and causing formation damage; (2) In the wellbore area, polymers and inorganic scales are wrapped around each other, forming an organic-inorganic composite scale with inorganic scale as the core, which is difficult to remove; (3) High-valent metal ions (especially Fe 3+ ) Cross-linking with polymers to form flocs that are easily adsorbed and retained in pipelines, causing blockage of oil pipelines; (4) Clay minerals and calcium and magnesium ion scaling, etc. In terms of elemental composition, they mainly contain Ca, Mg, Fe, Al and other elements.

[0004] Due to the above reasons, plugging removers are widely used in oil wells, and there are many types of plugging removers. However, the current plugging removers have poor solubility for silicates and carbonates, that is, poor removal ability for inorganic scale. Therefore, it is necessary to explore a chelating plugging remover for oil fields. Summary of the Invention

[0005] The present invention aims to provide a chelating plugging remover for oil fields, which has a good dissolution rate for inorganic scale and also provides a preparation method thereof.

[0006] The oilfield chelating plugging remover of the present invention is composed of the following raw materials, calculated by mass percentage: 10-12% of 1,2-bis(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid, 3-4% of disodium nitrilotriacetic acid, 4.0-5.0% of 1,2-dimethyl-3-hydroxy-4-pyridone, 8.4-8.6% of N,N'-ethylenediamine disuccinic acid, 1-1.5% of potassium dihydrogen phosphate, 1.7-1.9% of sodium polyoxyethylene lauryl ether sulfate, 0.5-0.7% of sodium ricinoleate, and the balance being water.

[0007] Preferably, the chelating plugging remover for oil fields described in the present invention is composed of the following raw materials, calculated by mass percentage: 11% of 1,2-bis(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid, 3.5% of disodium nitrilotriacetic acid, 4.5% of 1,2-dimethyl-3-hydroxy-4-pyridone, 8.5% of N,N'-ethylenediamine disuccinic acid, 1.3% of potassium dihydrogen phosphate, 1.8% of sodium polyoxyethylene lauryl ether sulfate, 0.7% of sodium ricinoleate, and the balance is water.

[0008] The oilfield chelating plugging remover of the present invention comprises 1,2-bis(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid and disodium nitrilotriacetic acid to remove calcium and magnesium ions in a synergistic manner. 1,2-bis(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid provides coordination sites with Ca by virtue of the four carboxylic acid oxygen atoms and two amino atoms in its molecular structure. 2+ In an acidic environment, the carboxylic acid oxygen atom binds to Ca through monodentate or bidentate coordination. 2+ In a weakly alkaline environment, the lone pair of electrons of the amino group can directly react with Ca 2+ The rigid skeleton of the benzene ring and ethane chain in the molecular structure of 1,2-bis(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid provides a pre-organized cavity, which makes the spatial arrangement of the coordination group consistent with Ca 2+ The ionic radius of the calcium carbonate and calcium sulfate generated during water injection development is highly matched, thereby destroying the lattice structure of blockages such as calcium carbonate and calcium sulfate, converting them into water-soluble substances and chelating free Ca 2+ , preventing it from re-scaling, and at the same time dispersing the already formed tiny precipitates by electrostatic repulsion. The chemical structure of disodium nitrilotriacetic acid contains a central nitrogen atom and three carboxylic acid groups, two of which exist in the form of sodium salts. The nitrogen atom and the oxygen atoms in the three carboxylic acid groups can serve as coordination sites to form multidentate coordination bonds with magnesium ions, thereby forming stable five-membered or six-membered cyclic chelates, significantly reducing the free energy of magnesium ions and improving the stability of the complex. The negative charge of the carboxylate group and Mg 2+ The positive charges of the nitrilotriacetic acid disodium salt attract each other, further enhancing the chelation effect. Thus, nitrilotriacetic acid disodium salt dissolves magnesium carbonate and magnesium sulfate precipitates in the blockage by forming a water-soluble chelate with magnesium ions. In addition, it also chelates free Mg 2+ , to prevent it from recombining with anions such as carbonate and sulfate to form secondary precipitation. 2+ It also has a certain chelating effect. The combined use of 1,2-bis(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid and disodium nitrilotriacetic acid broadens the pH range of the chelating plugging agent.

[0009] The metal organic compounds such as iron-containing porphyrin contained in crude oil decompose due to high temperature, high pressure or chemical treatment during the mining process, releasing Fe 3+ , or the iron parts such as downhole pipes corrode under acidic conditions, or the reinjection water or fracturing fluid contains soluble iron salts, and clay minerals dissolve and release Al under high temperature or acidic conditions. 3+ , which causes the injection well blockage to contain a certain amount of iron and aluminum ions. Therefore, it is necessary to add 1,2-dimethyl-3-hydroxy-4-pyridone and N,N'-ethylenediamine disuccinic acid to remove Fe 3+ and Al 3+ The suitable environment for 1,2-dimethyl-3-hydroxy-4-pyridone is acidic to weakly alkaline environment, through hydroxyl oxygen, keto oxygen and pyridine ring as electron donor atoms, 3+ and Al 3+ Both can form multidentate coordination and efficiently chelate Fe 3+ and Al 3 +. N,N'-ethylenediamine disuccinic acid is a biodegradable chelating agent for Fe 3+ It has a significant selective chelating effect. In addition, N,N'-ethylenediamine disuccinic acid also disperses particles and inhibits corrosion. To prevent the above-mentioned chelates from co-depositing with the oil phase, sodium polyoxyethylene lauryl ether sulfate and sodium ricinoleate are added. Sodium polyoxyethylene lauryl ether sulfate and sodium ricinoleate also reduce the oil-water interfacial tension and prevent the oil phase from agglomerating and clogging the pores.

[0010] The oilfield chelating plugging remover described in this invention also contains potassium dihydrogen phosphate. This disperses tiny scale particles through electrostatic repulsion, preventing them from aggregating into large particles and clogging pores. Furthermore, potassium dihydrogen phosphate interacts with other raw materials, stabilizing the concentration of free metal ions and enhancing the sustained effect of the chelating plugging remover. Furthermore, sodium polyoxyethylene lauryl ether sulfate and sodium ricinoleate synergistically alter the wettability of the rock surface, promoting crude oil stripping. The interaction with other raw materials enhances the removal of mixed scale.

[0011] The preparation method of the chelating plugging remover for oil fields of the present invention comprises the following steps: (1) Mix 1,2-bis(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid, disodium nitrilotriacetic acid, 1,2-dimethyl-3-hydroxy-4-pyridone, N,N'-ethylenediamine disuccinic acid and water, and stir until completely dissolved; (2) Then add potassium dihydrogen phosphate and continue stirring until it is completely dissolved; (3) Finally, add sodium polyoxyethylene lauryl ether sulfate and sodium ricinoleate and stir until they are completely dissolved to prepare a chelating declogging agent for oil fields.

[0012] in: The stirring and dissolving temperature in step (1) is 75-77° C., and the stirring and dissolving time is 33-35 min.

[0013] In step (2), the stirring and dissolving temperature is 70-72° C., and the stirring and dissolving time is 15-17 min.

[0014] In step (3), the stirring and dissolving temperature is 50-52° C., and the stirring and dissolving time is 20-22 min.

[0015] Compared with the prior art, the present invention has the following beneficial effects: (1) The oilfield chelating plugging remover described in the present invention comprises 1,2-bis(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid and disodium nitrilotriacetic acid, which act synergistically to remove calcium and magnesium ions. 1,2-dimethyl-3-hydroxy-4-pyridone and N,N'-ethylenediamine disuccinic acid act synergistically to remove aluminum and iron ions. Potassium dihydrogen phosphate is used as a stabilizer, and sodium polyoxyethylene lauryl ether sulfate and sodium ricinoleate are also added. By changing the wettability of the rock surface, crude oil stripping is promoted, and the agent interacts with other raw materials to enhance the removal effect of mixed scale. The synergistic effect between the raw materials ensures that the prepared oilfield chelating agent has a good dissolution rate for inorganic scale.

[0016] (2) The preparation method of the chelating plugging remover for oil fields of the present invention has a simple process and easy-to-control parameters. The prepared chelating plugging remover for oil fields has a wide range of applications, a small amount of addition, and mild use conditions. DETAILED DESCRIPTION

[0017] The present invention will be further described below with reference to the examples.

[0018] Example 1 The oilfield chelating plugging remover described in Example 1 is composed of the following raw materials, calculated by mass percentage: 11% 1,2-bis(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid, 3.5% disodium nitrilotriacetic acid, 4.5% 1,2-dimethyl-3-hydroxy-4-pyridone, 8.5% N,N'-ethylenediamine disuccinic acid, 1.3% potassium dihydrogen phosphate, 1.8% sodium polyoxyethylene lauryl ether sulfate, 0.7% sodium ricinoleate, and the balance water.

[0019] The preparation method of the chelating plugging remover for oil fields described in Example 1 comprises the following steps: (1) Mix 1,2-bis(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid, disodium nitrilotriacetic acid, 1,2-dimethyl-3-hydroxy-4-pyridone, N,N'-ethylenediamine disuccinic acid and water, and stir until completely dissolved; (2) Then add potassium dihydrogen phosphate and continue stirring until it is completely dissolved; (3) Finally, add sodium polyoxyethylene lauryl ether sulfate and sodium ricinoleate and stir until they are completely dissolved to prepare a chelating declogging agent for oil fields.

[0020] in: The stirring and dissolving temperature in step (1) is 76° C., and the stirring and dissolving time is 34 min.

[0021] The stirring and dissolving temperature in step (2) is 71° C., and the stirring and dissolving time is 16 min.

[0022] The stirring and dissolving temperature in step (3) is 51° C., and the stirring and dissolving time is 21 min.

[0023] Example 2 The oilfield chelating plugging remover described in Example 2 is composed of the following raw materials, calculated by mass percentage: 10% 1,2-bis(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid, 4% disodium nitrilotriacetic acid, 5.0% 1,2-dimethyl-3-hydroxy-4-pyridone, 8.4% N,N'-ethylenediamine disuccinic acid, 1% potassium dihydrogen phosphate, 1.7% sodium polyoxyethylene lauryl ether sulfate, 0.6% sodium ricinoleate, and the balance being water.

[0024] The preparation method of the chelating plugging remover for oil fields described in Example 2 comprises the following steps: (1) Mix 1,2-bis(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid, disodium nitrilotriacetic acid, 1,2-dimethyl-3-hydroxy-4-pyridone, N,N'-ethylenediamine disuccinic acid and water, and stir until completely dissolved; (2) Then add potassium dihydrogen phosphate and continue stirring until it is completely dissolved; (3) Finally, add sodium polyoxyethylene lauryl ether sulfate and sodium ricinoleate and stir until they are completely dissolved to prepare a chelating declogging agent for oil fields.

[0025] in: The stirring and dissolving temperature in step (1) is 75° C., and the stirring and dissolving time is 33 min.

[0026] The stirring and dissolving temperature in step (2) is 72° C., and the stirring and dissolving time is 17 min.

[0027] The stirring and dissolving temperature in step (3) is 52° C., and the stirring and dissolving time is 20 min.

[0028] Example 3 The oilfield chelating plugging remover described in Example 3 is composed of the following raw materials, calculated by mass percentage: 12% 1,2-bis(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid, 3% disodium nitrilotriacetic acid, 4.0% 1,2-dimethyl-3-hydroxy-4-pyridone, 8.6% N,N'-ethylenediamine disuccinic acid, 1.5% potassium dihydrogen phosphate, 1.9% sodium polyoxyethylene lauryl ether sulfate, 0.5% sodium ricinoleate, and the balance water.

[0029] The preparation method of the chelating plugging remover for oil fields described in Example 3 is composed of the following steps: (1) Mix 1,2-bis(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid, disodium nitrilotriacetic acid, 1,2-dimethyl-3-hydroxy-4-pyridone, N,N'-ethylenediamine disuccinic acid and water, and stir until completely dissolved; (2) Then add potassium dihydrogen phosphate and continue stirring until it is completely dissolved; (3) Finally, add sodium polyoxyethylene lauryl ether sulfate and sodium ricinoleate and stir until they are completely dissolved to prepare a chelating declogging agent for oil fields.

[0030] in: The stirring and dissolving temperature in step (1) is 77° C., and the stirring and dissolving time is 35 min.

[0031] The stirring and dissolving temperature in step (2) is 70° C., and the stirring and dissolving time is 15 min.

[0032] In step (3), the stirring and dissolving temperature is 50° C., and the stirring and dissolving time is 22 min.

[0033] Comparative Example 1 The preparation method of the oilfield chelating plugging remover described in Comparative Example 1 is the same as that in Example 1, the only difference being the raw material composition of the oilfield chelating plugging remover. The oilfield chelating plugging remover described in Comparative Example 1 is composed of the following raw materials, calculated by mass percentage: 4.5% 1,2-dimethyl-3-hydroxy-4-pyridone, 8.5% N,N'-ethylenediamine disuccinic acid, 1.3% potassium dihydrogen phosphate, 1.8% sodium polyoxyethylene lauryl ether sulfate, 0.7% sodium ricinoleate, and the balance water.

[0034] Comparative Example 2 The preparation method of the oilfield chelating plugging remover described in Comparative Example 2 is the same as that in Example 1, except that the raw material composition of the oilfield chelating plugging remover is different. The oilfield chelating plugging remover described in Comparative Example 2 is composed of the following raw materials, calculated by mass percentage: 11% 1,2-bis(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid, 3.5% disodium nitrilotriacetic acid, 1.3% potassium dihydrogen phosphate, 1.8% sodium polyoxyethylene lauryl ether sulfate, 0.7% sodium ricinoleate, and the balance water.

[0035] A dissolution test was performed on the chelated plugging removers for oil fields prepared in Examples 1-3 and Comparative Examples 1-2: the chelated plugging removers for oil fields prepared in Examples 1-3 and Comparative Examples 1-2 were weighed and mixed evenly with distilled water to obtain an aqueous solution of the chelated plugging remover for oil fields having a concentration of 5 wt%. 13.0 g of calcium carbonate / magnesium carbonate / ferric hydroxide / aluminum hydroxide was then added to 100 mL of the aqueous solution of the chelated plugging remover for oil fields and shaken at 40 ° C. The solution was then placed in a constant temperature incubator at 40 ° C for 24 h. The sample was taken out and filtered using medium-speed qualitative filter paper, and then dried at 105 ° C. Finally, the scale dissolution rate was calculated by the mass difference before and after the experiment. The results are shown in Table 1.

[0036] Table 1 Scale dissolution rate test results of chelating plugging agent for oil field

Claims

1. A chelating plugging remover for oil fields, characterized by: The invention is composed of the following raw materials in percentage by mass: 10-12% of 1,2-bis(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid, 3-4% of disodium nitrilotriacetic acid, 4.0-5.0% of 1,2-dimethyl-3-hydroxy-4-pyridone, 8.4-8.6% of N,N'-ethylenediamine disuccinic acid, 1-1.5% of potassium dihydrogen phosphate, 1.7-1.9% of sodium polyoxyethylene lauryl ether sulfate, 0.5-0.7% of sodium ricinoleate, and the balance is water.

2. The chelating plugging remover for oil fields according to claim 1, characterized in that: The product is composed of the following raw materials in percentage by mass: 11% of 1,2-bis(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid, 3.5% of disodium nitrilotriacetic acid, 4.5% of 1,2-dimethyl-3-hydroxy-4-pyridone, 8.5% of N,N'-ethylenediamine disuccinic acid, 1.3% of potassium dihydrogen phosphate, 1.8% of sodium polyoxyethylene lauryl ether sulfate, 0.7% of sodium ricinoleate, and the balance of water.

3. A method for preparing the chelating plugging remover for oil fields according to claim 1, characterized in that: It consists of the following steps: (1) Mix 1,2-bis(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid, disodium nitrilotriacetic acid, 1,2-dimethyl-3-hydroxy-4-pyridone, N,N'-ethylenediamine disuccinic acid and water, and stir until completely dissolved; (2) Then add potassium dihydrogen phosphate and continue stirring until it is completely dissolved; (3) Finally, add sodium polyoxyethylene lauryl ether sulfate and sodium ricinoleate and stir until they are completely dissolved to prepare a chelating declogging agent for oil fields.

4. The method for preparing the chelating plugging remover for oil fields according to claim 3, wherein: The stirring and dissolving temperature in step (1) is 75-77° C., and the stirring and dissolving time is 33-35 min.

5. The method for preparing the chelating plugging remover for oil fields according to claim 3, wherein: In step (2), the stirring and dissolving temperature is 70-72° C., and the stirring and dissolving time is 15-17 min.

6. The method for preparing the chelating plugging remover for oil fields according to claim 3, wherein: In step (3), the stirring and dissolving temperature is 50-52° C., and the stirring and dissolving time is 20-22 min.

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