Application of Special Formate Series Products for Anti-corrosion Maintenance of Oilfield Drilling Equipment

Oilfield drilling equipment operates in harsh environments with high temperatures, high salinity, high humidity, and acidic conditions. Components like drill pipes, casing, wellhead assemblies, and downhole tools are highly susceptible to electrochemical corrosion, pitting corrosion, and microbial corrosion, which significantly shorten equipment lifespan and increase operational safety risks. The following four core products are precisely designed to meet comprehensive anti-corrosion maintenance needs for drilling equipment, as detailed below:

1. Solid potassium formate (industrial grade ≥97%)

Core function: As the key component of long-term anti-corrosion and wellbore corrosion inhibition systems for drilling equipment, it forms a dense passive protective film on metal surfaces to isolate corrosive media and suppress electrochemical corrosion under high-temperature and high-pressure conditions. This solution is designed for long-term anti-corrosion maintenance of drill pipes, casing, and downhole tools.

Product Advantages: Chlorine-free formulation eliminates the risk of chloride ion pitting corrosion, with a corrosion rate significantly lower than that of chlorides on carbon steel; stable corrosion inhibition performance under high-temperature and high-pressure conditions (200°C); combined with antibacterial effects to prevent microbial corrosion; biodegradable and compliant with domestic and international environmental regulations for oil and gas extraction.

Usage: When sealing the equipment, prepare a 10%-30% aqueous solution and apply it to the surface of the equipment by soaking or spraying before sealing. For wellbore corrosion protection, add the annular space protective fluid and workover fluid system at a concentration of 5%-20%.

Common issues: Highly hygroscopic, requires sealed and dry storage; high-concentration solutions are prone to crystallization at low temperatures, necessitating heating for dissolution during winter use.

2. Liquid Potassium Formate (Industrial Grade ≥75%)

Core function: The primary product for on-site daily anti-corrosion maintenance of drilling equipment and continuous wellbore corrosion inhibition. It rapidly forms a corrosion-resistant protective film on metal surfaces, suitable for equipment maintenance during drilling intervals and long-term corrosion protection of casing.

Product Advantages: Liquid product requires no dissolution, ensuring on-site convenience; remains non-crystalline at-20°C, suitable for extreme cold oilfield operations; exhibits over 90% corrosion inhibition efficiency, significantly reducing casing corrosion rate; demonstrates excellent compatibility with drilling fluids and completion fluids without compromising system performance.

Usage: For on-site equipment maintenance, dilute the original solution 2-5 times and spray it to wipe the drill pipes and wellhead equipment. For wellbore corrosion protection, directly inject the original solution into the annulus protection fluid at a concentration of 3%-15%.

Common questions: Long-term storage requires sealing to prevent moisture absorption and dilution; mixing with strong acidic agents may reduce corrosion inhibition efficacy, necessitating separate dosing.

3. Industrial-grade Potassium Acetate (Solid/Liquid)

Core function: Passivation treatment for drilling equipment surfaces, corrosion and scale inhibition in surface circulation systems, pH adjustment of anti-corrosion systems, blocking acid medium corrosion, and maintenance of surface drilling equipment, circulation pipelines, and storage tanks.

Product Advantages: Excellent pH buffering capability, maintaining a weakly alkaline environment in the system for extended periods, preventing electrochemical corrosion; chlorine-free with low corrosiveness, preserving the equipment passivation film; also exhibits scale inhibition properties to prevent under-scale corrosion; synergizes with various corrosion inhibitors for enhanced efficacy.

Usage: Prepare the solid into a 5%-20% aqueous solution, dilute 1-3 times with liquid, and spray for surface passivation of equipment; continuously add to the circulating water system at a concentration of 0.2%-2%.

Common issues: Solid materials exhibit strong hygroscopicity and require sealed storage; excessive dosing may increase scaling risk, necessitating strict control of dosage.

4. Solid Sodium Formate (Industrial Grade ≥98%)

Core function: Low-cost corrosion protection for drilling equipment, auxiliary corrosion inhibition for drilling fluid systems, suitable for conventional corrosion protection of medium-shallow oilfield equipment and storage protection of idle equipment, and can be used in combination with potassium formate.

Product Advantages: Excellent cost-performance ratio, significantly reducing the cost of large-scale anti-corrosion operations; chlorine-free formulation, eliminating the risk of chloride-induced pitting corrosion; good water solubility for easy mixing, suitable for various on-site maintenance scenarios; low-foaming property, ensuring no interference with the circulation system operation.

Usage: When sealing idle equipment, prepare an 8%-25% aqueous solution to soak the equipment; for drilling fluid-assisted corrosion inhibition, add the solution at a concentration of 2%-10% to the system.

Common issues: The corrosion inhibition effect is weaker when used alone compared to potassium formate, and requires compound application in high-temperature deep wells; it is susceptible to strong acidic media and should be used in conjunction with pH adjusters.

5.Industry Use Cases

In a deep well operation area of an oilfield, the downhole casing and drill pipes have long been exposed to corrosive conditions from 180°C high-temperature, high-mineralized formation water. The original corrosion inhibition system exceeded annual corrosion rate limits, frequently causing casing leaks and drill pipe corrosion fractures, with annual equipment maintenance costs exceeding 8 million yuan. After adopting a new annular space protection fluid and equipment maintenance plan primarily using 75% potassium formate with potassium acetate as a supplement, the casing corrosion rate decreased by 92%, drill pipe service life doubled, and there were zero corrosion-related safety incidents throughout the year. Annual maintenance costs were reduced by 65%.