Oil and gas
15th Feb 2022

3 ways to optimise on-shore and off-shore seawater filtration

Seawater is commonly used as a water source for cooling, injection water, and freshwater generation in the oil and gas production processes. This is seen in both on-shore and off-shore facilities, due to its availability.

However, seawater requires robust treatment to remove potential hazards. It's a substance that's made up of biological contaminants, living organisms, and solids. This means that seawater can impact the longevity of your equipment over time, damage equipment, and cause fouling. 

Additionally, the make-up of seawater differs depending on the time of year and geographical location. For example, seawater sourced in the Indian Ocean will differ from that found in the North Sea. You need to consider how the seawater you use impacts your specific filtration system, and how to minimise it. 


How to optimise your filtration process for seawater

Optimising your filtration process for seawater is the secret weapon for improving the service life of your equipment. Here are three steps you can take to improve the resilience of your filtration process when filtering seawater. 

1. Choose the correct filter type

Some seawater applications will involve the removal of contamination in a narrow range of particle sizes, while others will be broad. You need a seawater filter system designed specifically for your local seawater quality.

However, this isn't something that you can predict or replicate under laboratory conditions. You need a filtration manufacturer with years of experience developing filtration solutions specifically for seawater. This way, you'll ensure your filtration solution will withstand any seawater variability. For example, the correct depth filter can more than double the service life of the prefiltration stage.

Your chosen filter manufacturer can conduct a filterability study to help you find the correct filter type. A filterability study uses small discs of filter material evaluated at various stages of your water treatment process to select the right efficiency and type throughout your treatment package. This tests how it works to find the most suitable filter type, ensuring it works in harmony with your system to improve efficiency.

Better water filtration = less downtime, fewer changeouts, and slicker production. Read our guide to start improving your processes.

2. Find the correct filter specification

Choosing the correct filter sizing basis is imperative to reducing the impact of corrosive seawater and other contaminants like algae.

To find the correct filter sizing basis, you must first understand what your pre-filtration stage looks like. What are the conditions of the upstream phase, and how has the water been treated? For example, if your seawater has already been through stages of pre-filtration, you will need a smaller filter sizing basis. 

Many filter manufacturers will simply measure flow rate, micron rating, and differential pressure. However, this is not enough to get accurate measurements for seawater which has lots of variabilities. To truly optimise your seawater filtration process, especially for on-shore and off-shore oil platforms, seek the support of a custom filtration manufacturer with experience in the oil and gas industry. 

3. Optimise your filters for biofouling

Biofouling is the unwanted growth of living organisms on surfaces. It negatively affects your filtration equipment, leading to more frequent maintenance, repairs, and replacements. Biofouling can contaminate water, block surfaces, and impact downstream equipment. This detrimentally affects the overall productivity of your process and, ultimately, your profits.

The best way to overcome biofouling is with anti-microbial and anti-algal technology for filtration. Seawater has lots of nutrients in it, and life will always grow. Especially when there is a constant flow of water. If you don't control this, it doesn't matter how well-optimised your filtration system is, it will impact you over time. 

But don't just take our word for it. We've tested our antimicrobial filtration solutions against untreated standard filters to measure their long-term benefits. The results demonstrate that anti-microbial technology has a 125% increase in dirt holding compared to standard. This also significantly lengthens cartridge life, reduces downtime, and delivers long-term cost savings. 

Follow these steps to improve the longevity of your seawater filtration equipment

These steps will help you improve the service life of your filtration equipment against seawater. However, the complex variability of seawater and the challenges this presents can't be overcome with generic solutions.

Seek support from an experienced filtration manufacturer to develop a solution for your specific needs. You can learn more about why anti-microbial depth cartridges are a vital step of the process in our informative case study. 

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