A deplugging agent for iron sulfide-containing plug and a preparation method thereof

Abstract

The present application relates to the technical field of oil and gas exploitation, and particularly relates to a kind of iron sulfide plug remover and its preparation method, comprising: 10-15 parts of composite chelating agent, 1-3 parts of scale inhibitor, 1-4 parts of penetrating agent, 0.5-2 parts of synergist, 3-8 parts of organic solvent, and 68-74.5 parts of water;Wherein, the composite chelating agent itself, including 30-60 parts of amino acid chelating agent, 20-30 parts of carboxylic acid chelating agent and 10-30 parts of organic phosphoric acid chelating agent by weight parts.The beneficial effects achieved by the present application are: high efficiency of plug removal, improved safety, and low equipment corrosion.

Description

Technical Field

[0001] This invention relates to the field of oil and gas reservoir development technology, and in particular to an iron-containing sulfide plugging agent and its preparation method. Background Technology

[0002] In the development of oil and gas reservoirs, scaling and blockage of oil and gas wells is an unavoidable problem. During the extraction process, as formation fluids enter the wellbore, a series of physicochemical reactions occur inside the wellbore, and insoluble substances gradually accumulate to form blockages.

[0003] Iron sulfides are mainly formed by the reaction of hydrogen sulfide and iron in the wellbore environment. They are commonly found in oil and gas wells, and their accumulation can severely impede fluid flow, reduce production efficiency, and even pose safety risks. Chemical dissolution is commonly used to remove these blockages. However, existing chemical dissolution methods often rely on acidic media. These acidic dissolution solutions generate hydrogen sulfide gas, which is highly toxic and poses an explosion hazard, threatening the safety of workers and the environment. Furthermore, the strong acid in the acidic media can corrode the metal equipment in the wellbore, shortening its lifespan and increasing maintenance costs.

[0004] With the oil and gas industry's increasing demands for safety, environmental protection, and efficiency, the development of non-acidic, efficient, and safe unblocking agents has become an urgent need for technological development.

[0005] Therefore, this invention aims to provide an innovative non-acidic chemical treatment method for dissolving iron sulfide blockages in oil and gas wells. Through the synergistic effect of composite chelating agents and surfactants, the generation of hydrogen sulfide is avoided from a chemical perspective, while improving dissolution efficiency and equipment compatibility. This method has significant industrial application value and theoretical significance.

[0006] This study aims to provide an innovative non-acidic chemical treatment method for dissolving iron sulfide blockages in oil and gas. Through the synergistic effect of composite chelating agents and surfactants, the generation of hydrogen sulfide is prevented from the chemical basis. At the same time, it has important industrial application value and theoretical significance due to its high dissolution efficiency and equipment compatibility. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide an iron sulfide blockage unblocking agent and its preparation method, which solves the problems of low unblocking efficiency, low safety, and easy corrosion of equipment by existing unblocking agents.

[0008] The objective of this invention is achieved through the following technical solution: In the first aspect, an iron sulfide blockage unblocking agent is provided, which, by weight, comprises: 10-15 parts of a composite chelating agent, 1-3 parts of a scale inhibitor, 1-4 parts of a penetrant, 0.5-2 parts of a synergist, 3-8 parts of an organic solvent, and 68-74.5 parts of water. The compound chelating agent itself, by weight, includes 30-60 parts of amino acid chelating agent, 20-30 parts of carboxylic acid chelating agent, and 10-30 parts of organophosphate chelating agent.

[0009] Furthermore, in the aforementioned composite chelating agent: the amino acid chelating agent is two or more of the following: ethylenediaminetetraacetic acid tetrasodium, glutamate diacetic acid tetrasodium, nitric acid triacetic acid sodium, glycine, and diethylenetriaminepentaacetic acid sodium. The carboxylic acid chelating agent is one or more of the following: sodium citrate, sodium tartrate, sodium malonate, and sodium gluconate. The organophosphate chelating agent is one or more of the following: aminotrimethylamine tetrasodium, diethylenetriaminepentamethylamine pentasodium, hydroxyethylidene diphosphate disodium, and diethylenetriaminetetramethylamine pentasodium.

[0010] Furthermore, the scale inhibitor is one or more of hydrolyzed polymaleic anhydride, polyaspartic acid, and polyepoxysuccinic acid.

[0011] Furthermore, the penetrant is one or more of isomeric decayl alcohol polyoxyethylene ether, isomeric tridecyl alcohol polyoxyethylene ether, lauramidopropyl betaine, and lauramidopropyl amine oxide.

[0012] Furthermore, the synergist is one or two of triazine, melamine, and triethanolamine.

[0013] Furthermore, the organic solvent is one or more of propylene carbonate, N,N-dimethylformamide, formamide, and ethylene glycol.

[0014] Secondly, a method for preparing an iron sulfide blockage unblocking agent is also provided, using the above-mentioned iron sulfide blockage unblocking agent; Preparation: Add water and organic solvent to the reaction vessel and heat to 40-50℃; Then, first add the penetrant and stir for 10-20 minutes, then add the chelating agent and stir for 10-20 minutes, then add the synergist and stir for 10-20 minutes, then add the scale inhibitor and stir for 10-20 minutes. Finally, cool to room temperature to complete the preparation.

[0015] The present invention has the following advantages: (1) It has a good effect on unblocking blockages; A specific combination of composite chelating agents is formulated. When the various chelating agents in the composite chelating agent react with iron sulfides, they do not cause negative interference, but rather work synergistically to make iron sulfides dissolve more efficiently. Furthermore, with the support of nonionic surfactants, this composite chelating agent can better penetrate into the micropores and gaps of the blockage, further improving the scale adhesion efficiency. Specifically, (1) the core technical feature of this invention is the construction of a composite chelation system, which works synergistically with iron sulfides in wellbore blockages through multiple complexation mechanisms to achieve efficient dissolution. The technical essence is that each chelating agent has different coordination bond forming capabilities, forming stable water-soluble complexes with metal ions (such as iron ions) through chelation. The technical advantage is that this synergistic effect can cover multiple types of iron sulfides, improve dissolution efficiency, and compared with a single chelating agent scheme, the complexation range is wider and the speed is faster. Moreover, based on a non-acidic environment, it avoids the risks caused by traditional acidic methods. (2) Nonionic surfactants, such as polyoxyethylene ether surfactants, are introduced as auxiliary components to enhance the wettability of the composite unblocking agent. The technical essence is to reduce the tension between the liquid and solid interface through nonionic surfactants, improve the spreading and penetration ability of the unblocking agent on the surface of wellbore blockages, make it easier for effective substances to penetrate into the micropores and cracks of the blockages, promote full contact between the composite chelation system and the blockages, and improve the scale dissolution and unblocking efficiency.

[0016] (2) It avoids the generation of hydrogen sulfide gas, reducing the risk of operation; it also avoids equipment corrosion. Specifically, the present invention uses a non-acidic unblocking agent, which can effectively avoid the generation of hydrogen sulfide gas and greatly reduce the risks during the operation. At the same time, compared with acidic unblocking agents, the use of non-acidic unblocking agents can effectively avoid the corrosion of the tubing by hydrogen ions, protecting the downhole tubing and equipment. Detailed Implementation

[0017] The present invention will be further described below, but the scope of protection of the present invention is not limited to the following description.

[0018] To make the objectives, 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. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0019] This solution discloses an iron sulfide blockage remover, which, by weight, comprises: 10-15 parts of a composite chelating agent, 1-3 parts of a scale inhibitor, 1-4 parts of a penetrant, 0.5-2 parts of a synergist, 3-8 parts of an organic solvent, and 68-74.5 parts of water. The compound chelating agent itself, by weight, includes 30-60 parts of amino acid chelating agent, 20-30 parts of carboxylic acid chelating agent, and 10-30 parts of organophosphate chelating agent.

[0020] It should be noted that: Among the compound chelating agents: amino acid chelating agents are two or more of the following: ethylenediaminetetraacetic acid tetrasodium, glutamic acid diacetic acid tetrasodium, aziridine triacetic acid sodium, glycine, and diethylenetriaminepentaacetic acid sodium; carboxylic acid chelating agents are one or more of the following: sodium citrate, sodium tartrate, sodium malonate, and sodium gluconate; organophosphate chelating agents are one or more of the following: aminotrimethylphosphonic acid tetrasodium, diethylenetriaminepentamethylphosphonic acid pentasodium, hydroxyethylidene diphosphate disodium, and diethylenetriaminetetramethylphosphonic acid pentasodium. The scale inhibitor is one or more of hydrolyzed polymaleic anhydride, polyaspartic acid, and polyepoxysuccinic acid. The penetrant is one or more of the following: isomeric decayl alcohol polyoxyethylene ether, isomeric tridecyl alcohol polyoxyethylene ether, lauramidopropyl betaine, and lauramidopropyl amine oxide; The synergist is one or two of the following: triazine, melamine, and triethanolamine; The organic solvent is one or more of propylene carbonate, N,N-dimethylformamide, formamide, and ethylene glycol.

[0021] When preparing the unblocking agent for iron sulfide blockage: (1) First add water and organic solvent to the reaction vessel and heat to 40-50℃; (2) Then, first add the penetrant and stir for 10-20 min, then add the chelating agent and stir for 10-20 min, then add the synergist and stir for 10-20 min, then add the scale inhibitor and stir for 10-20 min; (3) Finally, cool to room temperature to complete the preparation.

[0022] The following specific embodiments further illustrate this solution.

[0023] (Example 1) This embodiment discloses a deblocking agent for iron sulfide-containing blockages, which is prepared as follows: Add 83 parts water and 3 parts formamide to the reactor and heat to 40°C. Then add 1 part isomeric decahydrate polyoxyethylene ether, 10 parts chelating agent (which, by weight, contains 25% tetrasodium glutamate diacetate, 25% sodium triacetate, 20% sodium gluconate, and 30% pentasodium diethylenetriaminetetramethylidene phosphate), 2 parts triethanolamine, and 1 part hydrolyzed polymaleic anhydride. Stir for 10-20 minutes after each addition (within this time range). After stirring evenly, cool to room temperature to obtain unblocking agent JD-1.

[0024] (Example 2) Add 73.5 parts water and 8 parts ethylene carbonate to the reactor and heat to 45°C. Then add 1 part isomeric tridecyl alcohol polyoxyethylene ether, 15 parts chelating agent (which, by weight, contains 15% tetrasodium glutamate diacetate, 15% sodium triacetate, 20% sodium diethylenetriamine pentaacetate, 10% sodium gluconate, 10% sodium citrate, and 30% pentasodium diethylenetriamine tetramethylidene phosphate), 0.5 parts triazine, and 2 parts polyaspartic acid. Stir for 10-20 minutes after each addition (within this time range). After stirring evenly, cool to room temperature to obtain unblocking agent JD-2.

[0025] (Example 3) Add 75.5 parts water, 3 parts propylene carbonate, and 3 parts ethylene glycol to the reactor and heat to 50°C. Then, add 1 part lauramidopropylamine oxide, 15 parts chelating agent (which, by weight, contains 10% tetrasodium diglutamate, 10% sodium triacetate, 20% sodium diethylenetriacetate, 10% glycine, 10% sodium malonate, 10% sodium citrate, and 20% tetrasodium aminotrimethylphosphide), 0.5 parts melamine, and 2 parts polyaspartic acid. Stir for 10-20 minutes after each addition (any time within this range is acceptable). After stirring until homogeneous, cool to room temperature to obtain unblocking agent JD-3.

[0026] (Example 4) Add 80.5 parts water, 1 part formamide, and 3% propylene carbonate to the reactor and heat to 45°C. Then, add 2 parts lauramidopropyl betaine, 13 parts chelating agent (which, by weight, contains 30% ethylenediaminetetraacetic acid tetrasodium, 20% diethylenetriaminepentaacetic acid sodium, 10% glycine, 10% sodium tartrate, 10% sodium citrate, and 20% disodium hydroxyethylidene diphosphate), 0.5 parts melamine, and 3 parts polyaspartic acid. Stir for 10-20 minutes after each addition (any time within this range is acceptable). After stirring until homogeneous, cool to room temperature to obtain unblocking agent JD-4.

[0027] (Example 5) Add water, 2 parts N,N-dimethylformamide, and 3 parts ethylene glycol to the reactor and heat to 45°C. Then, add 1 part lauramidopropyl betaine, 1% isotridecyl alcohol polyoxyethylene ether, 15% chelating agent (which, by weight, contains 10% tetrasodium ethylenediaminetetraacetate, 20% tetrasodium glutamate diacetate, 20% sodium diethylenetriaminepentaacetate, 10% sodium tartrate, 20% sodium citrate, and 20% tetrasodium aminotrimethylphosphite), 1.5 parts triethanolamine, and 3 parts polyaspartic acid. Stir for 10-20 minutes after each addition (within this time range). After stirring until homogeneous, cool to room temperature to obtain the unblocking agent JD-5.

[0028] (Example 6) Add water, 2 parts formamide, and 3 parts propylene carbonate to the reactor and heat to 40°C. Then, add 1 part lauramidopropyl betaine, 1 part isotridecyl alcohol polyoxyethylene ether, 15 parts chelating agent (which, by weight, contains 5% tetrasodium ethylenediaminetetraacetate, 30% tetrasodium glutamate diacetate, 15% sodium diethylenetriaminepentaacetate, 5% sodium tartrate, 25% sodium citrate, and 20% tetrasodium aminotrimethylphosphide), 1.5 parts triethanolamine, and 3 parts polyaspartic acid. Stir for 10-20 minutes after each addition (within this time range). After stirring until homogeneous, cool to room temperature to obtain unblocking agent JD-6.

[0029] (Comparative Example 1) Add 83 parts water and 3 parts formamide to the reactor and heat to 40°C. Then add 1 part isomeric deca-ol polyoxyethylene ether, 10 parts tetrasodium glutamate diacetate, 2 parts triethanolamine, and 1 part hydrolyzed polymaleic anhydride in sequence. Stir for 10-20 minutes after each addition (within this time range). After stirring evenly, cool to room temperature to obtain unblocking agent JD-D1.

[0030] (Comparative Example 2) Add 7.35 parts water and 8 parts ethylene carbonate to the reactor and heat to 45°C. Then add 1 part isotridecyl alcohol polyoxyethylene ether, 15 parts sodium citrate, 0.5 parts triazine, and 2 parts polyaspartic acid in sequence. Stir for 10-20 minutes after each addition (within this time range). After stirring evenly, cool to room temperature to obtain the unblocking agent JD-D2.

[0031] (Comparative Example 3) Add 75.5 parts water, 3 parts propylene carbonate and 3 parts ethylene glycol to the reactor and heat to 50°C. Then add 1 part lauramidopropylamine oxide, 15 parts aminotrimethylphosphite tetrasodium phosphate, 0.5 parts melamine and 2 parts polyaspartic acid in sequence. Stir for 10-20 minutes after each addition of raw material. After stirring evenly, cool to room temperature to obtain the unblocking agent JD-D3.

[0032] (Comparative Example 4) Add 78 parts water, 1 part formamide, and 3 parts propylene carbonate to the reactor and heat to 45°C. Then add 2 parts lauramidopropyl betaine, 13 parts chelating agent (which, by weight, contains 30% ethylenediaminetetraacetic acid tetrasodium, 20% diethylenetriaminepentaacetic acid sodium, 10% glycine, 10% sodium tartrate, 10% sodium citrate, and 20% disodium hydroxyethylidene diphosphate), and 3 parts polyaspartic acid. Stir for 10-20 minutes after each addition of raw material. After stirring evenly, cool to room temperature to obtain the unblocking agent JD-D4.

[0033] (Experimental Example) Two g of iron sulfide scale sample was placed in an aging tank, and then 100 ml of unblocking agent was added. After sealing, the tank was placed at high temperature for 48 hours. The scale sample was then filtered, washed, and dried, and the scale dissolution efficiency of different unblocking solutions was analyzed. As shown in Table 1, the present invention has a good scale dissolution effect on iron sulfide scale samples, and the composite chelating system is significantly better than the single chelating agent system.

[0034] Table 1. Unblocking efficiency of different unblocking agents The above embodiments only illustrate preferred implementation methods, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of this invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this invention, and these all fall within the protection scope of this invention.

Claims

1. A deblocking agent for iron-containing sulfide blockages, characterized in that: By weight, it includes: 10-15 parts of compound chelating agent, 1-3 parts of scale inhibitor, 1-4 parts of penetrant, 0.5-2 parts of synergist, 3-8 parts of organic solvent, and 68-74.5 parts of water. The compound chelating agent itself, by weight, includes 30-60 parts of amino acid chelating agent, 20-30 parts of carboxylic acid chelating agent, and 10-30 parts of organophosphate chelating agent.

2. The unblocking agent for iron-containing sulfide blockages according to claim 1, characterized in that: In the aforementioned composite chelating agent: The amino acid chelating agent is two or more of the following: ethylenediaminetetraacetic acid tetrasodium, glutamate diacetic acid tetrasodium, aziridine triacetic acid sodium, glycine, and diethylenetriaminepentaacetic acid sodium. The carboxylic acid chelating agent is one or more of sodium citrate, sodium tartrate, sodium malonate, and sodium gluconate; The organophosphate chelating agent is one or more of the following: aminotrimethylphosphonic acid tetrasodium, diethylenetriaminepentamethylphosphonic acid pentasodium, hydroxyethylidene diphosphate disodium, and diethylenetriaminetetramethylphosphonic acid pentasodium.

3. A deblocking agent for iron-containing sulfide blockages according to claim 1 or 2, characterized in that: The water-resistant scale is one or more of hydrolyzed polymaleic anhydride, polyaspartic acid, and polyepoxysuccinic acid.

4. The unblocking agent for iron-containing sulfide blockages and its preparation method according to claim 3, characterized in that: The penetrant is one or more of the following: isomeric decayl alcohol polyoxyethylene ether, isomeric tridecyl alcohol polyoxyethylene ether, lauramide propyl betaine, and lauramide propyl amine oxide.

5. The unblocking agent for iron-containing sulfide blockages and its preparation method according to claim 3, characterized in that: The synergist is one or two of the following: triazine, melamine, and triethanolamine.

6. The unblocking agent for iron-containing sulfide blockages and its preparation method according to claim 3, characterized in that: The organic solvent is one or more of propylene carbonate, N,N-dimethylformamide, formamide, and ethylene glycol.

7. A method for preparing an iron-containing sulfide plugging agent, characterized in that: The unblocking agent containing iron sulfides as described in any one of claims 1 to 6 is used; Preparation: Add water and organic solvent to the reaction vessel and heat to 40-50℃; Then, first add the penetrant and stir for 10-20 minutes, then add the chelating agent and stir for 10-20 minutes, then add the synergist and stir for 10-20 minutes, then add the scale inhibitor and stir for 10-20 minutes. Finally, cool to room temperature to complete the preparation.

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