Injection Water

Pretreatment with ultrafiltration for reliable downstream operation

Proper pretreatment is a key factor for successful long-term performance of sulfate removal units (SRUs). Reliable pretreatment can remove particles, algae, bacteria, and sand to provide effective and stable operation downstream, reducing downtime. DuPont offers a variety of ultrafiltration (UF) products that are advantageous in meeting these needs.

DuPont offers UF in two different configurations: multi-element vessel (MEV) or single-element racks. The MEV system uses a pressure vessel with an adaptor to hold multiple UF modules operating in parallel. This reduces the amount of space needed and eliminates the need for piping manifolds. DuPont also offers UF cartridges that can fit into standard horizontal pressure vessels that are organized similarly to an RO system. This offering is a more flexible option for pre-built systems.

DuPont also offers UF modules with either polyvinylidene fluoride (PVDF) or polyethersulfone (PES) fibers. PVDF membranes are most common in oil & gas applications as they offer high chemical tolerance and are tolerant to temperature variations, promoting longer module life. Hollow-fiber PVDF membranes provide exceptionally high filtrate quality and very stable and long-term filtration operation.

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The largest portfolio of sulfate removal membranes in the market

DuPont introduced the first patented nanofiltration (NF) membranes for sulfate removal in the North Sea in 1987. Our ion-selective NF membranes have been used for over 20 years to treat seawater prior to injection into oil reservoirs. They remove sulfates to prevent and control reservoir scaling and souring.

Sulfate removal units (SRUs) employing NF membranes offer two main advantages in injection water treatment:

• The removal of sulfate eliminates the primary constituents from injection water that cause scale formation, thus reducing and eliminating this scaling problem.
• Hydrogen sulfide may be produced by chemical reduction of dissolved sulfate by sulfate-reducing bacteria, causing souring inside oil wells. By removing sulfate from injection water, hydrogen sulfide cannot be produced. This will reduce the potential for souring inside the wells.

The FilmTec™ SR90 product line is the best way to remove sulfates from seawater used for injection operations.

FilmTec™ Fortilife™ SR90

FilmTec™ Fortilife™ SR90 elements are specifically designed to handle biofouling in sulfate removal systems in oil production. These elements are equipped with advanced fouling resistance and cleanability features, helping plants reduce the number of cleanings while maintaining high sulfate rejection and permeability. With FilmTec™ Fortilife™ SR90 elements, operators can expect to improve SRU operations by reducing maintenance costs and downtime on offshore platforms. This is made possible by:

• Fouling-resistance technology reducing cleanings by 50%
• Low differential pressure
• Durable membrane chemistry
• More effective and efficient cleaning of biofilm and organic compounds

To learn more about FilmTec™ Fortilife™ SR90 elements, please contact us. 

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Reverse osmosis and nanofiltration to achieve successful low-salinity injection water

Low-salinity water injection is a popular enhanced oil recovery technique that has gained popularity the past decade. Using low-salinity water to inject into aging oil reservoirs results in enhanced oil recovery compared to using high-salinity water. The salinity level typically used in this low-salinity management strategy is 0.1% to 1%. DuPont offers a range of RO and NF membranes that can achieve the desired water quality for successful low-salinity injection.

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Membrane degasifiers to produce deoxygenated water

Oxygen and carbon dioxide in the water may damage industrial equipment and cause production issues due to corrosion. Other streams or effluents may become rich in hydrogen sulfide, ammonia, or methane. These streams cannot be discharged to the environment without treatment.

The DuPont™ Ligasep™ degasification product line uses hollow fibers to remove oxygen and carbon dioxide from water. These modules can be installed in series within the water treatment system, ensuring efficient degasification. Compared to the use of chemicals or stripping towers, the Ligasep™ product features:

• Chemical-free operation and residual-free removal vs. the use of chemical scavengers
• High packing density, which translates into smaller footprint, reduced weight and height vs. stripping towers
• A membrane barrier which prevents contaminants on the gas side to transfer to the water side
• Flexibility and robustness: the Ligasep™ product adapts to variable production demands
• Unattended and fully automated operation. Compared to other membrane degasifiers, the Ligasep™ product family is based on a thin gas permeable membrane which translates into the following advantages:
  • Ability to remove oxygen without using nitrogen gas
  • Reduction of water vapor transfer, which may cause auxiliary and piping equipment damage

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