Oilfield underground slow-release scale and corrosion inhibitor and production process thereof

Abstract

The invention relates to an oilfield underground slow-release scale and corrosion inhibitor and a production process thereof, and aims to solve the problems of scaling and corrosion caused by water injection in the oilfield exploitation process. According to the scale and corrosion inhibitor, various components such as the inorganic salt, the organic corrosion inhibitor and the natural plant extract are compounded, and a production process is combined, so that excellent properties such as long-acting slow release, efficient scale and corrosion inhibition, sterilization and algae removal, environmental protection and degradability are realized. The production process comprises the steps of raw material preparation, mixing reaction, melting homogenization, cooling forming, annealing treatment and the like, and stable performance and reliable quality of the scale and corrosion inhibitor are ensured by controlling process parameters of each step. The scale and corrosion inhibitor disclosed by the invention has obvious long-term effect, the workload of frequent addition and maintenance can be reduced, and the production cost is reduced; the environment-friendly and degradable characteristics meet the modern environment-friendly requirements, and the ecological environment can be protected. In addition, the scale and corrosion inhibitor has good adaptability and can adapt to different oil field geological conditions and fluid property differences.

Description

Technical Field

[0001] The invention relates to the technical field of oilfield chemical engineering technology, in particular to an oilfield downhole slow-release scale and corrosion inhibitor and a production process. Background Art

[0002] During the oilfield exploitation process, as the underground oil layer pressure gradually decreases, it is often necessary to inject a large amount of water or other fluids into the oil well to maintain or increase the oil well production. However, these injected waters interact with minerals, dissolved gases, and microorganisms in the formation underground, which can easily cause scaling and corrosion problems. Scaling will not only reduce the permeability of the oil well and increase the resistance to fluid flow, but may also block pipelines and equipment, resulting in a decrease in oil well production or even shutdown. At the same time, corrosion problems can seriously damage oil well equipment, shorten its service life, and increase maintenance and replacement costs.

[0003] Although traditional scale and corrosion inhibitors can alleviate these problems to a certain extent, they often have the following shortcomings: first, the effect is not long-lasting and requires frequent addition and maintenance; second, the composition is complex and may contain chemicals that are harmful to the environment; third, they are not very targeted and are difficult to adapt to the differences in geological conditions and fluid properties of different oil fields.

[0004] In recent years, with the continuous advancement of oilfield mining technology and the increasing requirements for environmental protection, the development of a long-lasting, environmentally friendly, and adaptable scale and corrosion inhibitor has become a research hotspot in the industry. Researchers have begun to explore the compounding of multiple ingredients such as inorganic salts, organic corrosion inhibitors, and natural plant extracts in order to obtain better scale and corrosion inhibition effects. At the same time, in order to improve the long-term effectiveness of scale and corrosion inhibitors, researchers have also tried to change the production process, such as microencapsulation, nano-materialization and other technical means, so that scale and corrosion inhibitors can be slowly released in the oil well environment and continue to play a role.

[0005] However, most of the scale and corrosion inhibitors currently available on the market have some deficiencies, such as poor long-term effectiveness, poor environmental performance, and weak adaptability. Therefore, developing a scale and corrosion inhibitor that has long-term slow-release performance, is environmentally friendly and degradable, and can adapt to different oilfield geological conditions and fluid properties is of great significance for improving oilfield production efficiency, reducing production costs, and protecting the ecological environment. Summary of the invention

[0006] In order to solve the problems of the prior art, the present invention provides an oilfield downhole slow-release scale inhibitor and a production process. The scale inhibitor and corrosion inhibitor achieve multiple functions such as long-term slow release, high-efficiency scale inhibition and corrosion inhibition, sterilization and algae removal, and environmental protection and degradation through carefully designed ratios and production processes. The purpose is to solve the problems existing in existing scale inhibitors and corrosion inhibitors and meet the actual needs of oilfield exploitation.

[0007] In order to solve the above technical problems, the present invention is achieved through the following technical solutions: First, an oilfield downhole slow-release scale and corrosion inhibitor and a production process are composed of the following components in proportion: 39-42 parts of quartz sand, 33-35 parts of soda ash, 14-19 parts of potassium salt, 3-10 parts of corrosion inhibitor, 2-5 parts of scale inhibitor, 0.5-2 parts of surfactant, 3-5 parts of corrosion inhibitor synergist, 3-10 parts of zinc salt, 3-10 parts of aluminum salt, 2-12 parts of borax, 3-4 parts of silver salt and 3-4 parts of iron salt.

[0008] In this aspect, it mainly relies on the synergistic effect and slow-release mechanism of various inorganic salts (potassium salt, aluminum salt, zinc salt, iron salt and silver salt). Under certain conditions, these inorganic salts work together with auxiliary materials such as quartz sand and soda ash to form a stable slow-release system. Specifically, each component is slowly released in the oil well environment, and through chemical reactions such as adsorption, precipitation, and complexation, the formation of scale is prevented, while the corrosion process of the metal surface is slowed down.

[0009] By controlling the dissolution rate and release rate of each component, long-term and effective scale and corrosion inhibition effects can be achieved. This slow-release characteristic allows the scale and corrosion inhibitor to continue to act on the oil well environment, avoiding the performance waste and short-term failure problems caused by the rapid release of traditional scale and corrosion inhibitors;

[0010] Potassium salts, aluminum salts and other components can react with scale-forming ions such as calcium and magnesium in water to form insoluble salt precipitates, which adsorb and fix scale ions, thereby preventing them from depositing on the surface of the equipment to form a scale layer. At the same time, the addition of surfactants reduces the surface tension of water, enhances the dispersibility of suspended particles and scale layers, and further improves the scale inhibition effect;

[0011] Silver salts and other components form a protective film on the metal surface, isolating direct contact with oxygen and water molecules, thereby slowing down or stopping the corrosion process of the metal. Corrosion inhibitors and other corrosion inhibitors work synergistically with other corrosion inhibitors to further enhance the overall corrosion inhibition effect. In addition, natural plant extracts such as tea polyphenols, tannic acid and other corrosion inhibitors can also form a non-toxic, biodegradable protective film on the metal surface to enhance the corrosion inhibition performance;

[0012] Components such as silver salts also have broad-spectrum bactericidal and algaecidal capabilities, which can effectively inhibit the reproduction of microorganisms in the water system, reduce the formation of biofouling, and further ensure the normal operation of production equipment.

[0013] In a specific embodiment of the first aspect, the zinc salt includes zinc chloride, zinc oxide and zinc sulfate, the aluminum salt includes aluminum chloride, aluminum oxide and aluminum sulfate, and the silver salt includes silver chloride, silver nitrate and silver sulfate.

[0014] In a specific embodiment of the first aspect, the corrosion inhibitor is set to include but is not limited to natural plant extracts such as tea polyphenols and tannic acid; the scale inhibitor is set to include but is not limited to polyaspartic acid; the surfactant is set to include but is not limited to sodium dodecylbenzene sulfonate; and the corrosion enhancer is set to include but is not limited to molybdate.

[0015] In a specific implementation of the first aspect, an oilfield downhole slow-release scale and corrosion inhibitor and a production process are prepared from the following raw materials in a mass fraction ratio: 39 parts of quartz sand, 34 parts of soda ash, 19 parts of potassium salt, 6 parts of corrosion inhibitor, 3 parts of scale inhibitor, 1 part of surfactant, 4 parts of corrosion inhibitor synergist, 10 parts of zinc salt, 3 parts of aluminum salt, 2 parts of borax, 3 parts of silver salt and 3 parts of iron salt.

[0016] In a specific implementation of the first aspect, an oilfield downhole slow-release scale and corrosion inhibitor and a production process are prepared from the following raw materials in a mass fraction ratio: 41 parts of quartz sand, 34 parts of soda ash, 17 parts of potassium salt, 7 parts of corrosion inhibitor, 3 parts of scale inhibitor, 1.3 parts of surfactant, 5 parts of corrosion inhibitor synergist, 7 parts of zinc salt, 10 parts of aluminum salt, 3 parts of borax, 3 parts of silver salt and 3 parts of iron salt.

[0017] Corrosion inhibitors can form a non-toxic, biodegradable protective film on the metal surface to effectively prevent corrosion; scale inhibitors can significantly prevent the scaling of calcium, magnesium and other ions in water to keep equipment clean; surfactants can reduce the surface tension of water, enhance the dispersibility of suspended particles and scale layers, and improve the cleaning effect; corrosion inhibitor enhancers can work synergistically with other corrosion inhibition ingredients to enhance the overall corrosion inhibition effect.

[0018] Secondly, the production process of the oilfield downhole slow-release scale and corrosion inhibitor includes the following preparation processes:

[0019] Step 1: Raw material preparation and pretreatment: Accurately weigh the raw materials according to the recipe requirements;

[0020] Step 2, mixing and preliminary reaction: dry-mix the solid raw materials in a high-speed mixer to ensure that the components are evenly dispersed; slowly add the liquid raw materials to the solid mixture after dry mixing, stirring while adding to ensure that the liquid raw materials are evenly distributed among the solid particles;

[0021] Step 3, melting and homogenization: the uniformly mixed raw materials are fed into a high-temperature melting furnace, the heating rate is controlled, and the raw materials are heated at a temperature below 1200°C at a heating rate of less than 10°C / min to gradually melt the raw materials. When the temperature rises to 1300-1450°C, an appropriate amount of clarifier is added, and the heating rate is controlled to be less than or equal to 5°C / min. Clarification and homogenization treatment are performed to eliminate bubbles, streaks and uneven bodies in the melt and improve the transparency and uniformity of the product.

[0022] Step 4: Cool down to 300-500℃ and inject into the mold for molding. The annealing temperature is less than or equal to 5℃ / min. The molded product is placed in an annealing furnace for annealing. The molded product is first heated in the annealing furnace to a temperature slightly higher than the strain point, and then cooled at a certain rate until room temperature.

[0023] In a specific embodiment of the second aspect, the clarifier is one or more of the raw materials potassium chloride, zinc chloride, aluminum chloride, sodium sulfate and potassium sulfate.

[0024] The beneficial effects of the present invention are:

[0025] 1. Through the carefully designed ratio and production process, the scale and corrosion inhibitor of the present invention can achieve long-term slow release in the oil well environment. This means that it can continue to work effectively after one addition, reducing the workload of frequent addition and maintenance, and reducing production costs. At the same time, the long-term slow release characteristics also ensure the stability and durability of the scale and corrosion inhibition effects, which is conducive to extending the service life of oil well equipment;

[0026] 2. The scale inhibitor and corrosion inhibitor of the present invention contains a variety of inorganic salts and organic corrosion inhibitors. These components can work synergistically to effectively prevent the scaling of calcium, magnesium and other ions in water, and form a protective film on the metal surface to slow down or prevent the corrosion process of the metal. Experimental data show that the scale inhibition rate and corrosion inhibition rate of the scale inhibitor in oil field produced water reach a high level, which can significantly reduce the scaling and corrosion problems of oil well equipment;

[0027] 3. The addition of silver salt and other components endows the scale inhibitor of the present invention with a broad spectrum of bactericidal and algaecidal capabilities. In the oil well environment, the growth and reproduction of microorganisms often lead to the formation of bio-scale, which increases the maintenance difficulty and operating cost of the equipment. The scale inhibitor of the present invention can effectively inhibit the growth of microorganisms, reduce the formation of bio-scale, and ensure the normal operation of oil well equipment;

[0028] 4. Some of the corrosion inhibitor ingredients in the scale inhibitor and corrosion inhibitor of the present invention are derived from natural plant extracts, such as tea polyphenols and tannic acid, etc. These ingredients are non-toxic, biodegradable, and meet environmental protection requirements. When oil well equipment is discarded or replaced, these ingredients will not pollute the environment, which is beneficial to protecting the ecological environment; by reducing the scaling and corrosion problems of oil well equipment, the scale inhibitor and corrosion inhibitor of the present invention can reduce the production suspension and maintenance costs caused by equipment failure, and improve oil recovery efficiency. At the same time, the long-term slow-release characteristics reduce the amount and addition frequency of scale inhibitors and corrosion inhibitors, further reducing production costs. The combined effect of these factors significantly improves the economic benefits of oil field production. DETAILED DESCRIPTION

[0029] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0030] The invention discloses an oilfield downhole slow-release scale and corrosion inhibitor and a production process, characterized in that the slow-release scale and corrosion inhibitor is composed of the following components in proportion: 39-42 parts of quartz sand, 33-35 parts of soda ash, 14-19 parts of potassium salt, 3-10 parts of corrosion inhibitor, 2-5 parts of scale inhibitor, 0.5-2 parts of surfactant, 3-5 parts of corrosion inhibitor synergist, 3-10 parts of zinc salt, 3-10 parts of aluminum salt, 2-12 parts of borax, 3-4 parts of silver salt and 3-4 parts of iron salt.

[0031] Zinc salts include zinc chloride, zinc oxide and zinc sulfate, aluminum salts include aluminum chloride, aluminum oxide and aluminum sulfate, and silver salts include silver chloride, silver nitrate and silver sulfate.

[0032] The invention is prepared by mixing the following raw materials in proportion by mass fraction: the corrosion inhibitor includes but is not limited to natural plant extracts such as tea polyphenols and tannic acid; the scale inhibitor includes but is not limited to polyaspartic acid; the surfactant includes but is not limited to sodium dodecylbenzene sulfonate; and the corrosion enhancer includes but is not limited to molybdate.

[0033] The production process of downhole slow-release scale and corrosion inhibitor in oil fields includes the following preparation processes: step 1, raw material preparation and pretreatment: accurately weigh the raw materials according to the formula requirements; step 2, mixing and preliminary reaction: dry-mix the solid raw materials in a high-speed mixer to ensure that the components are evenly dispersed; slowly add the liquid raw materials to the solid mixture after dry mixing, stirring while adding, to ensure that the liquid raw materials are evenly distributed among the solid particles; step 3, melting and homogenization: send the evenly mixed raw materials into a high-temperature melting furnace, control the heating rate, and heat them at a temperature below 1200°C at a heating rate of less than 10°C / min. The raw materials are heated at a temperature rate to gradually melt. When the temperature rises to 1300-1450°C, an appropriate amount of clarifier is added, and the heating rate is controlled to be less than or equal to 5°C / min. Clarification and homogenization treatment are performed to eliminate bubbles, streaks and uneven bodies in the melt and improve the transparency and uniformity of the product. Step 4: Cooling down to 300-500°C and injecting into the mold for molding. The annealing temperature is less than or equal to 5°C / min. The molded product is placed in an annealing furnace for annealing. The molded product is first heated in the annealing furnace to a temperature slightly higher than the strain point, and then cooled at a certain rate until room temperature.

[0034] The clarifier is one or more of the raw materials potassium chloride, zinc chloride, aluminum chloride, sodium sulfate and potassium sulfate.

[0035] The invention discloses an oilfield downhole slow-release scale inhibitor and a production process, which integrates slow-release, scale inhibition and corrosion inhibition performance. The produced water of a certain oilfield is used as a medium, and a weight loss method is adopted to determine the dissolution rate of the sample. The scale inhibition rate of the sample is determined according to the standard Q / SY126-2005 "Technical Requirements for Scale and Corrosion Inhibitors for Oilfield Water Treatment"; the corrosion inhibition rate of the sample is determined according to the standard SY / T5273-2000 "Performance Evaluation Method for Corrosion Inhibitors for Oilfield Produced Water". The obtained results show that the release period of the scale inhibitor in a certain oilfield is ≥12mon, and when the concentration of the scale inhibitor is 5-10mg / L, the scale inhibition rate is ≥95%, and the corrosion inhibition rate is ≥50%. The corrosion inhibitor has a variety of performances according to different proportions, and can be adapted to the corrosion inhibition of the corresponding proportion according to the different use requirements of the oil well. It is compatible with scale inhibitors and is used through a mixture of various potassium salts, aluminum salts, zinc salts, iron salts and silver salts, in combination with quartz sand and soda ash, and under the action of clarifiers, it not only achieves the corrosion inhibition effect but also greatly enhances the anti-scaling ability, avoids the need for continuous manpower operation and the need to equip specific dosing devices when using liquid scale inhibitors and corrosion inhibitors, improves the convenience of operation, enhances the effective period of slow release, and is continuously effective with a one-time investment. At the same time, it solves the problem that existing organic scale inhibitors and corrosion inhibitors require specific polymer skeletons and are expensive, avoids the situation where the added effective substances are difficult to separate from crude oil, and effectively avoids scaling, corrosion and microbial growth in the water system in various types of industrial water, so that the production equipment can operate safely, stably and with high quality, and improves the safety and economic benefits of the equipment.

[0036] Example 1: Oilfield downhole slow-release scale inhibitor and production process, prepared by the following raw materials in mass fraction ratio: 39 kg quartz sand, 34 kg soda ash, 19 kg potassium salt, 6 kg tea polyphenols, 3 kg polyaspartic acid, 1 kg sodium dodecylbenzene sulfonate, 4 kg molybdate, 10 kg zinc chloride, 3 kg aluminum chloride, 2 kg borax, 3 kg silver chloride and 3 kg ferric sulfate.

[0037] Production process:

[0038] Raw material preparation and pretreatment: According to the above ratio, accurately weigh each raw material, and carry out necessary pretreatment, screening and drying.

[0039] Mixing and preliminary reaction: Solid raw materials such as quartz sand, soda ash, potassium salt, zinc salt, aluminum salt, borax, silver salt and iron salt are dry mixed in a high-speed mixer to ensure that the components are evenly dispersed. Subsequently, liquid or solvent-soluble raw materials such as tea polyphenols, polyaspartic acid, sodium dodecylbenzene sulfonate and molybdate are dissolved in an appropriate amount of solvent and slowly added to the solid mixture after dry mixing, stirring while adding to ensure that the liquid raw materials are evenly distributed between the solid particles.

[0040] Melting and homogenization: The mixed raw materials are sent to a high-temperature melting furnace, and the heating rate is controlled. The raw materials are heated at a temperature below 1200°C and a heating rate of less than 10°C / min to gradually melt the raw materials. When the temperature rises to 1300-1400°C, an appropriate amount of clarifier (such as potassium chloride or potassium sulfate) is added, and the heating rate is controlled to be less than or equal to 5°C / min. Clarification and homogenization treatment are performed to eliminate bubbles, streaks and uneven bodies in the melt and improve the transparency and uniformity of the product.

[0041] Cooling molding and annealing: The molten homogenized material is cooled to 300-400℃, and then injected into the mold for molding. The molded product is placed in an annealing furnace, first heated to a temperature slightly higher than its strain point, and then cooled at a rate of no more than 5℃ / min until it reaches room temperature, completing the annealing process.

[0042] Effect evaluation:

[0043] According to the test of Q / SY126-2005 and SY / T5273-2000 and other standards, the release period of the oil field downhole slow-release scale inhibitor and corrosion inhibitor prepared in this embodiment in the oil field produced water is more than 12 months, the scale inhibition rate is not less than 95%, the corrosion inhibition rate is not less than 50%, and it shows good bactericidal and algaecidal performance, effectively ensuring the long-term stable operation of the oil well equipment.

[0044] Example 2: Oilfield downhole slow-release scale inhibitor and production process, prepared by the following raw materials in mass fraction ratio: 41 kg quartz sand, 34 kg soda ash, 17 kg potassium salt, 7 kg tannic acid, 3 kg polyaspartic acid, 1.3 kg sodium dodecylbenzene sulfonate, 5 kg molybdate, 7 kg zinc sulfate, 10 kg aluminum oxide, 3 kg borax, 3 kg silver nitrate (fine-tuned to adapt to different oil well environments) and 3 kg ferric chloride.

[0045] Production process:

[0046] Similar to production process 1, but it is important to adjust the stirring speed and mixing time according to the characteristics of tannic acid during the mixing and initial reaction stage to ensure that it is fully dispersed and evenly mixed with other components. In the melting and homogenization stage, it is also important to control the heating rate and the amount of clarifier added to obtain an ideal melting and homogenization effect.

[0047] Effect evaluation:

[0048] The oilfield downhole slow-release scale and corrosion inhibitor prepared in this embodiment also performed well in another group of oil well produced water, and the release period, scale inhibition rate and corrosion inhibition rate all reached or exceeded the expected targets. In addition, due to the adjustment of the types and proportions of silver salts and zinc salts, the product of this embodiment may show stronger sterilization and algae removal capabilities in a specific oil well environment, further improving the operating safety and stability of oil well equipment.

[0049] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. Oilfield downhole slow-release scale and corrosion inhibitor and production process, characterized in that: It is composed of the following ingredients in proportion: 39-42 parts of quartz sand, 33-35 parts of soda ash, 14-19 parts of potassium salt, 3-10 parts of corrosion inhibitor, 2-5 parts of scale inhibitor, 0.5-2 parts of surfactant, 3-5 parts of corrosion inhibitor enhancer, 3-10 parts of zinc salt, 3-10 parts of aluminum salt, 2-12 parts of borax, 3-4 parts of silver salt and 3-4 parts of iron salt.

2. The oilfield downhole slow-release scale and corrosion inhibitor and production process according to claim 1, characterized in that: The zinc salts include zinc chloride, zinc oxide and zinc sulfate, the aluminum salts include aluminum chloride, aluminum oxide and aluminum sulfate, and the silver salts include silver chloride, silver nitrate and silver sulfate.

3. The oilfield downhole slow-release scale inhibitor and production process according to claim 1 is made from the following raw materials in a mass fraction ratio: the corrosion inhibitor includes but is not limited to natural plant extracts of tea polyphenols and tannic acid; the scale inhibitor is set to include but is not limited to polyaspartic acid; the surfactant is set to include but is not limited to sodium dodecylbenzene sulfonate; the corrosion enhancer is set to include but is not limited to molybdate.

4. The downhole slow-release scale and corrosion inhibitor and production process for oil fields according to any one of claims 1 to 3 is prepared by mixing the following raw materials in proportion by mass: 39 parts of quartz sand, 34 parts of soda ash, 19 parts of potassium salt, 6 parts of corrosion inhibitor, 3 parts of scale inhibitor, 1 part of surfactant, 4 parts of corrosion inhibitor synergist, 10 parts of zinc salt, 3 parts of aluminum salt, 2 parts of borax, 3 parts of silver salt and 3 parts of iron salt.

5. The oilfield downhole slow-release scale and corrosion inhibitor and production process according to claim 1 is prepared by mixing the following raw materials in proportion by mass: 41 parts of quartz sand, 34 parts of soda ash, 17 parts of potassium salt, 7 parts of corrosion inhibitor, 3 parts of scale inhibitor, 1.3 parts of surfactant, 5 parts of corrosion inhibitor synergist, 7 parts of zinc salt, 10 parts of aluminum salt, 3 parts of borax, 3 parts of silver salt and 3 parts of iron salt.

6. The production process of slow-release scale and corrosion inhibitor for oil field, including the following preparation process: Step 1: Raw material preparation and pretreatment: Accurately weigh the raw materials according to the recipe requirements; Step 2, mixing and preliminary reaction: dry-mix the solid raw materials in a high-speed mixer to ensure that the components are evenly dispersed; slowly add the liquid raw materials to the solid mixture after dry mixing, stirring while adding to ensure that the liquid raw materials are evenly distributed among the solid particles; Step 3, melting and homogenization: the uniformly mixed raw materials are fed into a high-temperature melting furnace, the heating rate is controlled, and the raw materials are heated at a temperature below 1200°C at a heating rate of less than 10°C / min to gradually melt the raw materials. When the temperature rises to 1300-1450°C, an appropriate amount of clarifier is added, and the heating rate is controlled to be less than or equal to 5°C / min. Clarification and homogenization treatment are performed to eliminate bubbles, streaks and uneven bodies in the melt and improve the transparency and uniformity of the product. Step 4: Cool down to 300-500℃ and inject into the mold for molding. The annealing temperature is less than or equal to 5℃ / min. The molded product is placed in an annealing furnace for annealing. The molded product is first heated in the annealing furnace to a temperature slightly higher than the strain point, and then cooled at a certain rate until room temperature.

7. The production process of the oil field downhole slow-release scale and corrosion inhibitor according to claim 6, characterized in that: The clarifier is one or more of the raw materials potassium chloride, zinc chloride, aluminum chloride, sodium sulfate and potassium sulfate.