As fields and developments move into the more mature phases of development the production of increasing volumes of produced water is often the result. This, together with more stringent international environmental discharge legislation, and an increasing trend towards produced water re-injection, means that operators are increasingly obliged to treat produced water to higher standards prior to disposal or reuse.

The composition of produced waters is often very complex and many of the components are toxic and detrimental to the environment at large. It is essential that such components can be identified and quantified so that their environmental impact can be correctly assessed.

Produced waters can contain a whole cocktail of undesirable chemicals and agents the most frequently encountered being:

• Dispersed Hydrocarbons
• Phenols
• Poly Aromatic hydrocarbons
• Benzene, Toluene, Ethyl Benzene and Xylene
• Heavy metals such as arsenic, lead, mercury and cadmium
• Production chemicals, scale / corrosion inhibitors, demulsifiers, and residual biocides.

Discharge of any or all of these to the environment is becoming increasing more difficult (for obvious reasons) as greater emphasis is place on environmental issues by all parties involved in the oil industry.

Re-injection of produced waters can have clear economic and ecological advantages over surface disposal. This is based on the premise that if the produced water has to be treated to a high degree for surface disposal, then an operator might as well re-inject it for pressure maintenance or simply disposal.

Whether the produced water is to be treated for surface disposal or re-injection a full and thorough understanding, of both the chemical and physical properties of that water are essential for any successful treatment design, in terms of minimising the effects of dissolved or dispersed contaminants on water quality.

In addition to the environmental concerns of deliberate discharge of produced water, there is always the ever present danger of accidental release of hydrocarbon and aqueous fluids into the environment. Produced waters are often hot, saline and very corrosive, and hence very aggressive towards carbon steel materials.

Oil Plus has the expertise and specialist analytical equipment to fully characterise any produced water, and has a well established worldwide track record in produced water analysis and produced water treatment system design.