Corrosion Inhibitor

Oilfield corrosion is usually not caused by common metal oxidation and rust, but by the multiphase fluid in an oxygen-free reducing environment, in which dissolved acidic gases come into contact with steel pipes and induce corrosion. The formation of corrosion depends on the generation of galvanic cells, where a small potential difference causes oxidation of iron and reduction of water, which in turn forms corrosion.

Common types of corrosion in oil fields include:

Carbon dioxide (CO2)-induced "sulfur-free corrosion": This type of corrosion is ubiquitous, especially under high pressure and high temperature conditions, because carbon dioxide dissolved in water forms carbonic acid and reacts with the iron surface. Although a protective film can be formed under certain conditions, corrosion will continue once the conditions change. Sulfur-free corrosion usually forms small pits with smooth edges and a relatively low metal loss rate.

Hydrogen sulfide (H2S)-induced "acid corrosion": This type of corrosion is more destructive. Hydrogen sulfide reacts directly with the iron surface to form a ferrous sulfide (FeS) protective film, but fluid flow destroys this film, leading to continuous corrosion. Acid corrosion also causes hydrogen atoms to diffuse into the metal, causing blistering, embrittlement and cracks in the steel, while sulfate-reducing bacteria (SRB) also exacerbate local corrosion.

To control corrosion, film-forming corrosion inhibitors are widely used in oil fields. These inhibitors work by interrupting the formation of galvanic cells. The positively charged film-forming surfactants are adsorbed onto the negatively charged surface of the pipe, and their hydrophobic tails aggregate to form a hydrophobic layer, reducing the contact between water and the pipe, thereby reducing the corrosion potential.

UNPChemicals has developed a variety of CIMET™ series products for oilfield corrosion, providing different forms of corrosion inhibition, including oil-soluble, oil-soluble/water-dispersible and water-soluble products. Refer to the table below for specific product selection and application guidance.

Oilfield Corrosion Inhibitors: Protection for Critical Infrastructure
Corrosion inhibitors are essential chemical solutions used in oil and gas operations to safeguard metal equipment from destructive corrosion caused by harsh downhole environments. These specialized formulations create protective barriers on metal surfaces to combat various corrosion types, including acid attack from CO₂/H₂S, oxygen corrosion in water systems, and microbial-induced corrosion. Advanced inhibitor chemistries like amino compounds form strong chemisorbed films, hydroxyethyl imidazoline derivatives offer excellent thermal stability for deep wells, while oligomeric ester amines provide environmentally friendly protection with long-lasting film persistence. UNPChemicals' CIMET series represents cutting-edge corrosion protection technology, combining these active components in optimized formulations that deliver superior performance across diverse operating conditions - from high-temperature sour gas fields to offshore seawater injection systems - while meeting stringent environmental regulations.

Why are corrosion inhibitors so important in oilfield operations?

Corrosion inhibitors play a vital role in maintaining operational integrity and safety throughout oil and gas production systems. Without proper protection, corrosive elements like acidic gases, brine, and bacteria can cause catastrophic equipment failures, leading to expensive repairs, production downtime, and potential environmental incidents. Effective inhibitors can reduce corrosion rates by over 90%, significantly extending the service life of pipelines, well casings, and processing equipment. The economic impact is substantial - proper corrosion control can save millions in maintenance costs while preventing unplanned shutdowns that might disrupt entire production fields.

What makes UNPChemicals' CIMET inhibitors different from conventional products?
The CIMET series stands out through its innovative formulation technology that combines multiple protection mechanisms in a single product. Unlike traditional inhibitors that may only work under specific conditions, CIMET products incorporate advanced film-forming amines, vapor-phase inhibitors, and metal passivators to provide comprehensive protection across diverse environments. They demonstrate exceptional performance in extreme conditions (up to 150°C and high salinity) while being environmentally compliant. The series also offers customized solutions for different application methods, whether continuous injection, batch treatment, or squeeze applications, ensuring optimal protection tailored to each operational scenario.

How are corrosion inhibitors applied in oilfield systems?
Corrosion inhibitors are typically applied through three main methods in oilfield operations. Continuous injection involves metering the inhibitor into production streams at carefully controlled rates, ideal for pipelines and processing facilities. Batch treatment applies concentrated doses periodically, commonly used for well casings and storage tanks. Squeeze treatments force inhibitor solutions into the formation near the wellbore, providing extended protection for downhole equipment. The CIMET series includes formulations specifically designed for each application method, with chemistries optimized for different contact surfaces, flow regimes, and environmental conditions encountered throughout production systems.

What safety and environmental considerations apply to corrosion inhibitor use?
Modern corrosion inhibitors like the CIMET series are developed with stringent safety and environmental standards in mind. They are formulated to minimize toxicity while maintaining high performance, complying with international regulations such as OSPAR for offshore applications. Safety data sheets provide detailed handling instructions, requiring proper PPE during application. Environmental considerations include biodegradability testing and marine organism toxicity assessments. UNPChemicals' products undergo rigorous evaluation to ensure they meet both performance requirements and environmental responsibility standards, balancing effective corrosion protection with sustainable operation practices.

How do operators monitor the effectiveness of corrosion inhibitors?
Operators employ multiple monitoring techniques to assess inhibitor performance. Corrosion coupons and electrical resistance probes provide direct measurement of metal loss rates. Linear polarization resistance (LPR) instruments offer real-time corrosion rate data. Fluid analysis tracks iron counts and bacterial activity that influence corrosion. Advanced methods include ultrasonic thickness measurements and intelligent pigging for pipeline inspections. The CIMET series is supported by comprehensive monitoring protocols, with UNPChemicals providing technical assistance to interpret data and optimize treatment programs, ensuring continuous protection throughout the asset lifecycle.