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Roemex Limited spacer Speciality Oilfield Chemicals spacer Production of oil and gas spacer Filtration is performed to remove particulates spacer Highly effective at low treatment rates spacer
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preheadingWater Injection
Problem Area
sub WAX
Chemical Management




The injection of waters, both aquifer and seawater, is extensively used to support and maintain the production of oil and gas.

The main physical treatments of injection water are:

  • Filtration
  • De-oxygenation

Filtration is performed to remove particulates, macro-invertebrates and organic matter down to less than 5 microns in size. De-oxygenation of the water is required to reduce corrosion and aerobic bacterial growth. Primary oxygen removal is normally either by use of a vacuum tower or a gas stripping tower. These reduce the level of oxygen in the water from around 9ppm to less than 50ppb. Further oxygen removal is achieved by the addition of an oxygen scavenger downstream of the deaeration vessel.


Chemical Treatments

The main areas for the application of chemical treatments associated with water injection systems including the following:

  • Injectivity problems
  • Bacterial growth and proliferation
  • Filtration
  • Produced water re-injection
  • Oxygen removal
  • Erosion and drag reduction

Coagulants and Filter Aids - these chemicals are applied to improve the efficiency of the filtration system and aid removal of organic components, which can contribute to foaming of injection water. Coagulants and filter aids typically work at very low dose rates.

Oxygen Removal / Corrosion Control - achieved by deaeration towers and by the application of oxygen scavengers. It is vital that low oxygen concentrations are achieved to protect the topsides equipment, injection wells and subsea flowlines from oxidative corrosion.

Bacterial Control – achieved by chlorination treatment (electro-chlorination or hypochlorite addition) upstream of deaeration and batch biocide addition downstream of deaeration. Depending on which biocide is used, the biocide may interfere with the oxygen scavenger and therefore scavenger should be turned off during batch treatments.

Antifoam – generally applied upstream of deaeration if required. Roemex have designed non-foaming biocides for water injection treatments so as to prevent the requirement for antifoam addition. However if foaming is not dependent on biocidal constituents Roemex Antifoam RX-5505 is a chemical of choice being active at low concentrations and being environmentally friendly.

Injectivity - in order to maximise injectivity and sweep efficiency where no spare injection capacity exists, a polymer flow improver / drag reducer can be applied.


Roemex’s Range of Water Injection Chemicals

Roemex have developed a range of products for treatment of injection water. All chemicals have been designed to be highly effective at low treatment rates. Roemex believe that water injection plants should be considered in totality and that proper chemical management and application be in place from start up. On stream monitoring for critical factors such as dissolved oxygen content, residual chlorides and sulphites, plus routine bacterial population monitoring should be applied to optimise chemical dose rates.

RX-202 - RX-202 Oxygen Scavenger is an aqueous solution of ammonium bisulphite and is the most common oxygen scavenger used in water injection systems and pipeline hydrotesting.


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RX-206 - RX-206 is an aqueous solution of sodium meta-bisulphite, also used in pipeline hydrotesting and water injection systems.


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RX-5505 - RX-5505 is a product in our range of defoamer chemicals, which has been formulated specifically for use in water injection systems and has a superior environmental category.


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RX-4615 S/1 - RX-4615 S/1 is a proprietary blend of partially hydrolysed polymers, high molecular weight polyacrylamide emulsions specifically developed for drag reduction applications.


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RX-270 - RX-270 is a gluteraldehyde-based solution, effective against a wide range of micro-organisms including sulphate-reducing bacteria (SRB) and acid-producing bacteria (APGHB / APB) commonly found in oil / water and water systems.


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RX-1212 - RX-1212 is a non-oxidizing THPS (tetrakis hydroxymethyl phosphonium sulphate) based, broad-spectrum biocide highly effective against a wide range of micro-organisms in particular the sulphate-reducing bacteria (SRB).


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For further detailed product information and case histories please contact a Roemex sales representative
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