Every oilfield is characterized by the presence of water and gas that come to the surface together with the oil being extracted. This water, the produced water, has to be separated from the oil and the gasses.
Apart from oil, main pollutants are heavy metals, dissolved and suspended solids.
The natural destination of Produced Water is to be injected, discharged to the sea or reused.
Cannon Artes supplies solutions for both onshore and offshore production plants.
Produced Water – On shore
In on-shore applications 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 oil, scaling salts and solids to avoid plugging of the formation rocks and to maximize the residual life of an oil reservoir that is strictly related to the “size” of the solids particles.
Cannon Artes’ state of the art solution for treatment of produced water is based upon a sequence of stages defined according to the influent oil and solid content.
- The first stage is characterised by a de-oiling unit arranged on oil interceptors: Coalescing Plates (CPI) or Tilted Plates (TPI) separators. Such equipment employs a series of corrugated plate packs inclined at reverse angles in close proximity; an effective technique for enlarging oil droplets and settling solids within a limited footprint.
- Induced Gas Flotation (IGF) or Dissolved Gas Flotation (DGF) is the second stage: small bubbles of gas rising through oil contaminated water attach themselves to oil droplets, accelerating their path to the surface where the oil layer builds up and is skimmed off.
- The third stage consists in an extremely accurate filtration process in order to achieve the maximum purity from solid particles and to allow water re-injection. Cannon Artes Walnut Shell Filters are particularly suitable for this application assuring removal of up to 98% of the contaminants present in the feed water and removal by a coalescing process of the residual oil.