Environment-friendly dual-purpose corrosion and scale inhibitor for oil and gas drilling, collection and transportation and preparation method of environment-friendly dual-purpose corrosion and scale inhibitor

Abstract

The invention discloses an environment-friendly oil and gas drilling collection and transportation dual-purpose corrosion and scale inhibitor which is characterized by comprising the following components in percentage by mass: 40%-50% of polyaspartic acid, 20%-30% of unsaturated aliphatic carboxylic acid, 10%-20% of soluble sulfonate (on a dry basis), 2%-5% of soluble zinc salt (on a zinc ion basis) and the balance of deionized water. Through precise polymerization and modification processes, the corrosion and scale inhibition synergistic effect of all the components is remarkably improved. The effect enables the product to keep long-acting stability under harsh water quality conditions such as high temperature and high hardness, corrosion and scaling risks of drilling, production and gathering and transportation facilities are effectively reduced, the frequency of shutdown maintenance is reduced, the cost is saved, meanwhile, the service life of equipment is prolonged, and the operation efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of corrosion and scale inhibitors for oil and gas drilling, production, gathering and transportation, specifically to an environmentally friendly corrosion and scale inhibitor for both oil and gas drilling, production, gathering and transportation and its preparation method. Background Technology

[0002] With the continued growth of global energy demand and increasingly stringent environmental protection requirements, oil and gas drilling, production, and gathering technologies are constantly being innovated. Scaling is a common phenomenon during drilling, production, and gathering. This is caused by the precipitation of inorganic salt ions in formation water or injected water due to changes in temperature, pressure, or chemical environment, forming insoluble inorganic salt deposits (such as calcium carbonate, calcium sulfate, and barium sulfate) that accumulate on the surfaces of wellbores, drilling tools, pipelines, and equipment. These deposits lead to reduced drilling and gathering efficiency, corrosion of downhole tools and pipelines, reduced production capacity, and even safety accidents. Meanwhile, strict regulations such as the Water Pollution Prevention and Control Law on wastewater discharge are also driving the development of higher standards for wastewater treatment processes. How to synergistically achieve multi-objective optimization—efficient wastewater treatment, reduced facility maintenance costs, extended equipment lifespan, and improved operational efficiency—has become a critical technical bottleneck that current drilling, production, and gathering technologies urgently need to overcome. The effectiveness of this solution directly impacts the economic benefits and environmental sustainability of oilfield production. Existing corrosion and scale inhibitors mainly inhibit the deposition of inorganic scale such as calcium carbonate and calcium sulfate through the following mechanisms: (1) chelation effect, forming stable complexes with calcium, magnesium and other ions; (2) dispersion effect, preventing the aggregation and deposition of particulate matter; (3) lattice distortion effect, interfering with crystal growth. These agents can inhibit material corrosion while inhibiting scale, for example, by forming a film on the inner wall of the pipeline to reduce the rate of electrochemical corrosion. Among them, organophosphonate corrosion and scale inhibitors (such as aminotrimethylene phosphonic acid ATMP and hydroxyethylidene diphosphonic acid HEDP) have become the mainstream agents for oil and gas drilling and gathering systems due to their excellent chemical stability and long-term effectiveness.

[0003] However, organophosphonate agents have a dual drawback: firstly, their high biotoxicity significantly inhibits the physiological activity of nitrifying bacteria and other microorganisms, as well as aquatic organisms such as fish, leading to decreased biodegradation capacity and disruption of the food chain; secondly, the phosphorus they contain easily induces eutrophication, promoting abnormal proliferation of algae such as cyanobacteria, resulting in dissolved oxygen depletion, decreased water transparency, and consequently, damage to the stability of aquatic ecosystems and threats to drinking water safety. These environmental risks have become increasingly prominent with long-term application. Therefore, reducing or replacing the use of organophosphonate agents has become a core issue that urgently needs to be addressed in the field of oil and gas field water treatment technology, concerning the transformation of drilling and production systems towards environmentally friendly technologies and the development of new environmentally friendly agents. Summary of the Invention

[0004] This invention aims to provide an environmentally friendly corrosion and scale inhibitor suitable for both oil and gas drilling and gathering / transportation, and its preparation method, to replace organophosphonate compounds. By screening high-performance non-phosphorus organic compounds and optimizing the molecular modification and polymerization process, equivalent corrosion and scale inhibition performance is achieved.

[0005] To achieve the above objectives, the present invention provides an environmentally friendly corrosion and scale inhibitor suitable for both oil and gas drilling and extraction, which adopts the following technical solution: An environmentally friendly corrosion and scale inhibitor for both oil and gas drilling and extraction comprises the following components by weight percentage: Polyaspartic acid: 40%-50% Unsaturated aliphatic carboxylic acids: 20%-30% Soluble sulfonates (on a dry basis): 10%-20% Soluble zinc salts (based on zinc ions): 2%-5% Deionized water: Balance.

[0006] Among them, the unsaturated aliphatic carboxylic acid is acrylic acid; the soluble sulfonate (on a dry basis) is sulfonated tannin (on a dry basis); and the soluble zinc salt (on a zinc ion basis) is zinc gluconate (on a zinc ion basis).

[0007] This invention also discloses a method for preparing an environmentally friendly corrosion and scale inhibitor suitable for both oil and gas drilling and extraction, comprising the following steps: The first step is to dissolve the soluble sulfonate in preheated deionized water at 50-60℃ and stir continuously for 1 hour to fully dissociate the sulfonic acid groups. The second step is to dissolve the soluble zinc salt in 40°C warm water and stir for 30 minutes before use. The third step involves placing unsaturated aliphatic carboxylic acids in a dropping tank, while simultaneously adding polyaspartic acid and pretreated sulfonate solution to the reaction vessel. After mixing for 1 hour, unsaturated aliphatic carboxylic acids are added dropwise at a rate of 250-300 mL / min. Fourth step: After mixing for 2 hours, nitrogen gas is introduced to replace the air, the temperature is raised to 70°C, and then the initiator solution is added dropwise at a constant rate over 1 hour to maintain the reaction temperature at (75±2)°C. A trace amount of chain transfer agent is added and the reaction continues for 3 hours. The temperature is then lowered to 60°C, the pretreated zinc salt solution is added, and the reaction continues for 2 hours. Fifth step: add deionized water to dilute the total monomer concentration to 30%; after cooling to room temperature, purify to remove small molecule impurities, and obtain the target product by spray drying.

[0008] The pH value of the entire process control system is maintained between 6.0 and 7.0.

[0009] Compared with the prior art, the beneficial effects of the present invention are: This invention significantly enhances the synergistic corrosion and scale inhibition effect of each component through precise polymerization and modification processes. This effect enables the product to maintain long-term stability under harsh water quality conditions such as high temperature and high hardness, effectively reducing the risk of corrosion and scaling in drilling and gathering facilities, reducing downtime for maintenance and saving costs, while extending equipment life and improving operational efficiency. In terms of environmental protection, this invention uses a phosphorus-free formula, completely replacing traditional organophosphonate corrosion inhibitors (such as ATMP and HEDP). The selected raw materials are all highly biodegradable and can decompose rapidly in the natural environment, preventing eutrophication and heavy metal residues from the source, thus meeting the needs of sustainable industrial development. Detailed Implementation

[0010] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below.

[0011] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0012] An environmentally friendly corrosion and scale inhibitor for both oil and gas drilling and extraction comprises the following components by weight percentage: Polyaspartic acid: 40%-50% Unsaturated aliphatic carboxylic acids: 20%-30% Soluble sulfonates (on a dry basis): 10%-20% Soluble zinc salts (based on zinc ions): 2%-5% Deionized water: Balance.

[0013] Among them, polyaspartic acid serves as the main comonomer, providing scale inhibition and dispersion properties; unsaturated aliphatic carboxylic acids enhance the dispersion and chelation of inorganic scale; soluble sulfonates (on a dry basis) provide metal corrosion inhibition and scale inhibition synergistic effects; and soluble zinc salts (on a zinc ion basis) act as corrosion inhibitors.

[0014] Preferably, the unsaturated aliphatic carboxylic acid is acrylic acid; the soluble sulfonate (on a dry basis) is sulfonated tannin (on a dry basis); and the soluble zinc salt (on a zinc ion basis) is zinc gluconate (on a zinc ion basis).

[0015] A method for preparing an environmentally friendly corrosion and scale inhibitor suitable for both oil and gas drilling and extraction includes the following steps: The first step is to dissolve the soluble sulfonate in preheated deionized water at 50-60℃ and stir continuously for 1 hour to fully dissociate the sulfonic acid groups. The second step is to dissolve the soluble zinc salt in 40°C warm water and stir for 30 minutes before use. The third step involves placing unsaturated aliphatic carboxylic acids in a dropping tank, while simultaneously adding polyaspartic acid and pretreated sulfonate solution to the reaction vessel. After mixing for 1 hour, unsaturated aliphatic carboxylic acids are added dropwise at a rate of 250-300 mL / min. Fourth step: After mixing for 2 hours, nitrogen gas is introduced to replace the air, the temperature is raised to 70°C, and then the initiator solution is added dropwise at a constant rate over 1 hour to maintain the reaction temperature at (75±2)°C. A trace amount of chain transfer agent is added and the reaction continues for 3 hours. The temperature is then lowered to 60°C, the pretreated zinc salt solution is added, and the reaction continues for 2 hours. Fifth step: Add deionized water to dilute the total monomer concentration to 30%; after cooling to room temperature, purify to remove small molecule impurities, and obtain the target product by spray drying.

[0016] The pH value of the entire process control system is maintained between 6.0 and 7.0.

[0017] Example Dissolve 20 kg of sulfonated tannin in 60 kg of deionized water preheated to 50-60℃, adjust the pH to 8.0-9.0 with sodium hydroxide solution, and stir for 1 hour. Separately, dissolve 5 kg of zinc gluconate in 40℃ warm water to prepare a 20% solution, add sodium citrate stabilizer, and stir for 30 minutes. Place 25 kg of acrylic acid in a dropping device, and simultaneously add 45 kg of polyaspartic acid and 80 kg of pretreated sulfonated tannin solution to the reactor. After mixing for 1 hour, add acrylic acid dropwise at a rate of 250-300 mL / min. After mixing for 2 hours, purge the air with nitrogen and raise the temperature to 70℃. Add ammonium persulfate solution (1-2% monomer mass) and sodium bisulfite (oxidant to reducing agent molar ratio 1:1) dropwise at a constant rate over 1 hour, maintain the reaction temperature at (75±2)℃, and add isopropanol as a chain transfer agent, continuing the reaction for 3 hours. After cooling to 60℃, add 25 kg of zinc gluconate solution and continue the reaction for 2 hours. Add 230 kg of deionized water to bring the total monomer concentration to 30%. (Adjust the pH to 6.0-7.0 with acetic acid or ammonia during polymerization). After cooling to room temperature, purify to remove impurities, and then spray dry to obtain the target product.

[0018] The environmentally friendly oil and gas drilling and gathering / transport corrosion and scale inhibitors prepared in the above embodiments were tested for scale inhibition and corrosion inhibition rates. The relevant tests were conducted in accordance with "Q / SH CG0133-2021 Technical Requirements for Scale Inhibitors for Oilfield Water Treatment" and "Q / SY 126-2014 Technical Specifications for Corrosion and Scale Inhibitors for Oilfield Water Treatment".

[0019] Experimental data Q / SH CG0133-2021 Scale inhibition rate (10mg / L) Corrosion inhibition rate (30 mg / L) Example 95% 82% Q / SY 126-2014 Scale inhibition rate (30 mg / L) Corrosion inhibition rate (50 mg / L) Example 92% 87% This invention offers significant advantages in raw material selection, with carboxyl groups playing a crucial role. Carboxyl groups form stable chelates with metal ions such as calcium and magnesium, effectively preventing scaling. In polymer design, introducing carboxyl groups into the side chains significantly enhances scale inhibition, as the high reactivity of carboxyl groups strengthens the polymer's chelating properties. This invention specifically selects polyaspartic acid as the base material because it is inherently rich in carboxyl groups. Furthermore, during polymerization, modifying the acrylic monomers with side chains further introduces additional carboxyl functional groups to maximize the scale inhibition effect. Sulfonated tannins not only provide abundant sulfonic acid groups, effectively enhancing scale inhibition performance to suppress the deposition of inorganic salt scale, but also serve as a key additive in drilling fluid systems. Through strong adsorption, they inhibit the hydration and swelling of bentonite particles, effectively controlling filtration loss and improving mud cake quality, thereby significantly enhancing the overall stability of the drilling fluid system. Simultaneously, as a highly efficient salt-resistant dispersant, sulfonated tannins can effectively disintegrate the network structure of clay particles in high-salt or even saturated brine environments, significantly reducing mud viscosity, decreasing flow resistance, and improving rheological properties, thus greatly improving the efficiency and safety of drilling operations. Similarly, sulfonated tannins also exhibit significant advantages in crude oil gathering and transportation. Their unique molecular structure, combining hydrophilic sulfonic acid groups and hydrophobic tannin aromatic cores, makes them a natural surfactant. They can oriented at the oil-water interface, effectively reducing interfacial tension and forming stable oil-in-water (O / W) microemulsions, dispersing high-viscosity heavy oil into fine droplets, greatly reducing the internal frictional resistance of crude oil flow. Especially when facing complex reservoir conditions with high asphaltene content, high mineralization, and easy scaling, sulfonated tannins, with their excellent dispersing, viscosity-reducing, and scale-inhibiting synergistic effects, not only ensure efficient flow but also possess outstanding environmental advantages due to their environmental friendliness and biodegradability. To optimize overall drilling fluid performance and crude oil gathering and transportation efficiency, this invention appropriately increases the proportion of sulfonated tannins to achieve synergistic effects of scale inhibition and dispersion. Zinc ions are provided by zinc gluconate, avoiding the introduction of ineffective ions such as sulfate and chloride ions, thereby reducing the risk of corrosion or precipitation. The gluconate anions (negatively charged) dissociated from zinc gluconate in aqueous solution have excellent dispersing properties. They can quickly adsorb onto the surface of inorganic salt precipitates, clay, and other particles, significantly increasing the negative charge density on the particle surface and forming a stable double-layer protective structure. This structure prevents particles from approaching and agglomerating through strong electrostatic repulsion, effectively inhibiting aggregation. Furthermore, gluconate can provide additional carboxyl functional groups, further enhancing the ability to chelate metal ions and improving overall scale inhibition and stability. In terms of environmental protection, the raw materials selected for the product all possess excellent biodegradability. This means that after completing their use cycle, they can be effectively decomposed by microorganisms in nature and ultimately return to the natural cycle. Compared to other chemical agents with equivalent performance on the market, this characteristic significantly reduces the potential environmental impact of the product during the disposal stage.It not only significantly reduces the risk of persistent harmful substances accumulating in soil and water, but also greatly alleviates long-term pressure on ecosystems and biodiversity, demonstrating our concrete commitment to environmental protection.

[0020] Although the present invention has been described above with reference to embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, as long as there is no structural conflict, the features in the disclosed embodiments can be combined with each other in any manner. The lack of an exhaustive description of these combinations in this specification is merely for the sake of brevity and resource conservation. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An environmentally friendly corrosion and scale inhibitor for both oil and gas drilling and extraction, characterized in that, It includes the following components by weight percentage: Polyaspartic acid: 40%-50% Unsaturated aliphatic carboxylic acids: 20%-30% Soluble sulfonates (on a dry basis): 10%-20% Soluble zinc salts (based on zinc ions): 2%-5% Deionized water: Balance.

2. The environmentally friendly oil and gas drilling and extraction corrosion and scale inhibitor according to claim 1, characterized in that, The unsaturated aliphatic carboxylic acid is acrylic acid; the soluble sulfonate (on a dry basis) is sulfonated tannin (on a dry basis); and the soluble zinc salt (on a zinc ion basis) is zinc gluconate (on a zinc ion basis).

3. A method for preparing an environmentally friendly corrosion and scale inhibitor suitable for both oil and gas drilling and extraction, characterized in that, Includes the following steps, The first step is to dissolve the soluble sulfonate in preheated deionized water at 50-60℃ and stir continuously for 1 hour to fully dissociate the sulfonic acid groups. The second step is to dissolve the soluble zinc salt in 40°C warm water and stir for 30 minutes before use. The third step involves placing unsaturated aliphatic carboxylic acids in a dropping tank, while simultaneously adding polyaspartic acid and pretreated sulfonate solution to the reaction vessel. After mixing for 1 hour, unsaturated aliphatic carboxylic acids are added dropwise at a rate of 250-300 mL / min. Fourth step: After mixing for 2 hours, nitrogen gas is introduced to replace the air, the temperature is raised to 70°C, and then the initiator solution is added dropwise at a constant rate over 1 hour to maintain the reaction temperature at (75±2)°C. A trace amount of chain transfer agent is added and the reaction continues for 3 hours. The temperature is then lowered to 60°C, the pretreated zinc salt solution is added, and the reaction continues for 2 hours. Fifth step: add deionized water to dilute the total monomer concentration to 30%; after cooling to room temperature, purify to remove small molecule impurities, and obtain the target product by spray drying.

4. The preparation method of an environmentally friendly oil and gas drilling and extraction dual-purpose corrosion and scale inhibitor according to claim 2, characterized in that, The pH value of the entire process control system is maintained between 6.0 and 7.0.