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Produced Water & Injection Water Treatment

In an oil reservoir crude oil normally lays on water which is called “formation water”. The drilling and extraction operations that are aimed to maximise the production of oil, may be counterbalanced by huge production of contaminated water which is called “Produced Water”. Apart from oil, main pollutants are heavy metals, dissolved and suspended solids, radio-active elements. Many oil reservoirs are aging nowadays being in production since a long time and, on the other hand, production of oil needs to be maximised under the pressure of high oil prices. 

The natural destination of Produced Water is injection back as “flooding water” into the reservoir in order to “move” oil toward the extraction hole, this is normally done below the oil layer into the “formation” rocks. Since the rocks are highly porous the Produced Water to be injected must be free from solids, oil and scaling salts to avoid “plugging” of the “formation” rocks. The residual life of an oil reservoir is strictly related to the “size” of the solids particles still present in the injection water.

Treatment of produced water is therefore mainly based upon a sequence of stages according to the influent oil and solid content. The first stage is characterised by a de-oiling unit arranged on oil interceptors (coalescing plates or tilted plates type) or flotation units. In order to achieve the maximum purity from solid particle, downstream the first stage an extremely accurate filtration process is employed. Walnut shell filters are particularly suitable for this application assuring removal of up to 98% of the contaminants present in the feed water.

The possibility to treat “Produced Water” is, from one point of view, a way to reduce the impact on the environment; from the other a strong possibility to increase production of oil and therefore profitability.

In some cases Produced Water is not enough to cope with the demand of water to be injected in the oil basin to keep the pressure high. Specific Injection Water treatment systems are designed for this purpose featuring in particular vacuum degassing, fine filtration and chemical conditioning.

Aware of that importance, ARTES Ingegneria (BONO Artes) is able to provide design, manufacturing and commissioning of a full range of products that could set the “state-of-the-art” solution in “Produced Water” & “Injection Water” treatment.