Efficient Treatment of Polymer-Containing Wastewater in Oilfields: SINOKLE's Innovative Solution

Enhanced Oil Recovery (EOR) and the Challenges of Polymer-Containing Wastewater Treatment

In the field of oil extraction, the widespread application of Enhanced Oil Recovery (EOR) has played an important role in ensuring energy security worldwide. However, the byproduct of this technology — polymer-containing wastewater — has become a significant environmental challenge for oilfield companies.

Polymer-containing wastewater refers to the produced water generated after the application of polymer flooding technology in EOR. Due to the presence of flooding agents (usually high molecular weight polymers like polyacrylamide), this type of wastewater exhibits high viscosity, poor flowability, and complex composition. Compared to conventional oilfield produced water, polymer-containing wastewater presents a significantly higher treatment difficulty.

Statistics indicate that in China, for example, major domestic oilfields generate billions of cubic meters of polymer-containing wastewater annually. If discharged without effective treatment, it not only causes severe environmental pollution but also wastes a large amount of recyclable water resources. Efficient treatment of polymer-containing wastewater has thus become an essential issue for the sustainable development of oilfields.

Treatment Challenges

Polymer-containing wastewater is difficult to treat mainly due to the following reasons:

1. High viscosity and poor flowability: The residual polymers, such as polyacrylamide, increase the viscosity of the water significantly, which causes poor flowability and clogging of treatment equipment.

2. High suspended solids content: Polymers mix with soil, sand, and other substances from the formation, creating large amounts of suspended solids that are difficult to settle. These solids have small particle sizes and high stability, making them difficult to remove with conventional filtration equipment.

3. Severe oil-water emulsification: During the EOR process, crude oil comes into contact with the polymer, forming highly emulsified oil-water mixtures with extremely small oil droplets (typically below 10 microns), making separation extremely difficult.

4. Prone to filter material clogging: Traditional filter materials like quartz sand and walnut shells have smooth surfaces and lack activated groups, making them ineffective in adsorbing polymers. Over time, the filter material clogs and loses effectiveness, requiring frequent backwashing or replacement, which leads to high maintenance costs.

Limitations of Traditional Technologies

Historically, the treatment of polymer-containing wastewater has relied on several conventional methods:

1. Gravity settling: This method relies on gravity to allow suspended solids to settle naturally. However, the small particle size and low density of the solids in polymer-containing wastewater result in very low settling efficiency.

2. Traditional flotation: Air bubbles are generated to carry suspended solids upwards for separation. However, this method has limited effectiveness for highly emulsified polymer-containing wastewater.

3. Standard filter media filtration: Traditional filter materials like quartz sand, walnut shells, and anthracite coal are used as filter media. However, these materials have smooth surfaces and limited porosity, leading to poor adsorption of polymers and fine suspended solids. They are prone to clogging and failure.

4. Chemical demulsification: Chemical agents are added to break emulsions, but this increases operational costs and may cause secondary pollution.

Each of these traditional methods has its limitations and cannot effectively meet the comprehensive requirements of high-efficiency oil removal, thorough filtration, stable operation, and cost reduction.

SINOKLE’s New Solution

To address the industry’s pain points in polymer-containing wastewater treatment, Shenzhen Clear Science & Technology Co., Ltd (SINOKLE) has introduced a combination treatment process with the core equipment: Cyclonic Dissolved Ozone Flotation (CDOF) + Cyclonic Dissolved-gas Flotation Unit (CDFU) + KFM Activated Media Filter. This innovative technology tackles the industry's challenges with technical breakthroughs.

KFM Core Principle

The KFM Activated Media Filter uses a new type of silicate material as its filter media. This activated filter media is processed through 60 precision preparation steps and superhydrophilic modification technology, offering the following unique properties:

· Melting point up to 1,200°C: Excellent high-temperature resistance

· Density of approximately 1.25: Moderate density, good backwashing performance

· No odor, insoluble in water: Chemically stable

· Permanent negative surface charge: This is the core advantage of KFM.

The Magical Effect of Negative Charge

The permanent negative charge on the KFM filter media surface is its technological core. This negative charge provides two key benefits:

1. Efficient adsorption: The negative charge generates electrostatic attraction to positively charged particles and colloids in the water, effectively capturing particles smaller than 20 microns. This is a critical feature that ordinary filter media cannot achieve.

2. Antibacterial function: The negative charge suppresses bacterial growth, preventing biological slime formation on the filter media surface and extending the media’s lifespan.

Technical Features

The KFM Activated Media Filter offers the following significant advantages:

1. High filtration precision: Ordinary filter media typically have a filtration precision of 20-50 microns, while the KFM media can achieve a filtration precision of less than 2 microns, significantly improving effluent quality.

2. No clogging, easy backwashing: Traditional filter media require frequent backwashing due to clogging from pollutants. KFM filter media, due to their negative charge, prevent pollutants from adhering to the surface, making backwashing effective and ensuring long-term operation without clogging.

3. Long lifespan: Ordinary filter media need to be replaced every 1-2 years, while KFM filter media have a lifespan of over 5 years, resulting in lower lifecycle costs.

4. Stable effluent: KFM filter media are not sensitive to water quality fluctuations, ensuring stable effluent quality even with significant changes in influent water quality.

5. Strong adaptability: KFM filter media are suitable for various types of oilfield wastewater, including conventional produced water, polymer-containing wastewater, and fracturing flowback fluids, making them versatile for various applications.

Application Case Studies

The KFM Activated Media Filter has been successfully applied in several oilfield projects with remarkable results.

In a large oilfield polymer-containing wastewater treatment project, KFM Activated Media Filters were used for deep treatment. Actual operating data showed:

· Suspended solids removal rate: Reduced from 80 mg/L to less than 5 mg/L

· Particle size distribution: Nearly all particles larger than 2 microns were removed

· Backwashing cycle: Increased by more than 3 times compared to traditional filter media

· Effluent quality: Stable and compliant with reinjection standards

The successful implementation of this project has solved the polymer-containing wastewater treatment problem for oilfield companies, resulting in significant economic and environmental benefits.

In Conclusion

As countries worldwide continue to tighten environmental regulations, oilfield wastewater treatment has become a key limiting factor for the development of oilfield companies. The KFM Activated Media Filter, with its unique technological advantages, offers an efficient, reliable, and cost-effective solution for polymer-containing wastewater treatment.