Biocide

Biocides for Oilfield Applications
Biocides are essential chemical agents used in oilfield operations to control microbial growth that can lead to microbiologically influenced corrosion (MIC), biofilm formation, and reservoir souring. These specialized formulations target bacteria, fungi, and algae in water injection systems, pipelines, and production facilities. Common active ingredients include benzalkonium chloride, didecyldimethyl ammonium chloride, and dodecyl dipropylene triamine.

UNPChemicals' BIMET Series
The BIMET product line represents UNPChemicals' advanced biocide technology, combining optimized formulations of these active ingredients for superior microbial control in challenging oilfield environments. BIMET biocides demonstrate thermal stability (up to 120°C), compatibility with production chemicals, and effectiveness across pH ranges (3-11). Their unique synergistic formulations provide both immediate kill and long-term protection, particularly against acid-producing and sulfate-reducing bacteria in hydraulic fracturing fluids, produced water systems, and seawater injection applications. The series includes tailored products for shock treatment and continuous injection protocols, helping operators maintain system integrity while meeting environmental regulations.

Unproduced oil and gas formations are biologically free, but once they come into contact with the surface, they can become biocontaminated. The downhole environment is harsh and only a few organisms can survive, but once these organisms enter, they find an environment with less competition and rich nutrients. The greatest risk of biocontamination during production occurs when surface fluids are injected directly into the reservoir, such as produced water re-injection (PWRI), scale squeezes, and other wellbore remediation or stimulation measures. In these operations, biological purification of the fluids is critical and is usually achieved using chemical biocides.

Microorganisms in the reservoir can have many negative effects on production. For example, sessile bacteria that form slimes can block pore channels and reduce the water absorption index of injection wells. The most serious damage is usually caused by sulfate-reducing bacteria (SRB), such as Desulfovibrio. These bacteria convert sulfate in the injected water into hydrogen sulfide gas, which, over time, can cause increased corrosion, increase production costs (such as hydrogen sulfide removal costs), and cause health and safety issues. These bacteria are extremophiles that can survive in reservoir environments with high salt, pressure, temperature, and neutral pH.

Once bacterial colonies are formed, complete sterilization is almost impossible. Therefore, the key to controlling microbial contamination downhole is to use adequate biocides for treatment before fluid injection.

The BIMET™ series of biocide provided by UNPChemicals are non-oxidizing surface-active organic products that can adsorb on cell walls and disrupt the normal functions of cells. Although their sterilization rate may not be as fast as oxidizing biocides, they are less corrosive to production pipelines and can even be used as corrosion inhibitors, especially quaternary ammonium compounds. These biocides stop working after reaching the surface environment and are easily biodegraded into harmless metabolites. Choosing the right biocide requires consideration of the target microorganisms, applicable regulatory requirements, and recommended treatment methods.

Why are biocides necessary in oilfield operations?

Biocides play a critical role in oilfield operations by preventing the growth of harmful microorganisms that can lead to serious operational challenges. Sulfate-reducing bacteria (SRB) produce hydrogen sulfide, which causes reservoir souring and creates safety hazards. Acid-producing bacteria corrode metal surfaces, leading to equipment failure and costly repairs. Biofilms formed by bacterial colonies can clog pipelines and reduce production efficiency. Without proper biocide treatment, these microbial activities can significantly impact production rates, equipment lifespan, and overall operational safety.

What are the key advantages of UNPChemicals' BIMET biocide series?
The BIMET biocide series offers several distinct advantages for oilfield applications. These formulations combine multiple active ingredients to create synergistic effects, resulting in superior microbial control at lower dosage rates. They exhibit excellent thermal stability, maintaining effectiveness in high-temperature downhole conditions up to 120°C. The products are designed for rapid action against planktonic bacteria while also penetrating and disrupting established biofilms. BIMET biocides are compatible with other production chemicals and have minimal impact on downstream processes, making them ideal for continuous injection programs or batch treatments in various oilfield systems.

How should biocides be applied in oilfield systems?
Biocide application in oilfield systems requires careful consideration of several factors. The treatment strategy typically involves either continuous low-dose injection or periodic shock treatments, depending on the system conditions and microbial load. Continuous injection is often used in water injection systems to maintain constant protection, while batch treatments are preferred for pipelines and storage tanks. The dosage and frequency should be determined based on regular microbial monitoring, system volume, and water chemistry. BIMET biocides can be applied through chemical injection pumps at wellheads, added to fracturing fluids, or introduced at various points in water treatment systems for comprehensive microbial control.

What safety precautions are necessary when handling oilfield biocides?
Proper safety measures are essential when handling oilfield biocides due to their concentrated antimicrobial properties. Personnel should always wear appropriate personal protective equipment (PPE), including chemical-resistant gloves, safety goggles, and protective clothing. Handling should occur in well-ventilated areas to prevent inhalation exposure. BIMET products are formulated with safety in mind, but they still require careful storage away from incompatible materials and strict adherence to manufacturer's handling guidelines. Emergency eyewash stations and safety showers should be accessible in areas where biocides are handled, and all personnel should be trained in proper spill response procedures.

How do biocides impact the overall oil production process?
When properly selected and applied, biocides positively impact oil production processes without affecting product quality. Effective biocide treatment maintains system cleanliness by preventing microbial-induced corrosion that can damage pipelines and processing equipment. By controlling SRB populations, biocides prevent hydrogen sulfide contamination that could downgrade crude oil quality. BIMET biocides are specifically designed to target problematic microorganisms while being inert to hydrocarbon streams, ensuring they don't interfere with separation processes or final product specifications. Their use ultimately contributes to more efficient operations, reduced downtime, and extended asset lifespan throughout the production chain.