Deoiling of Produced Water
and Dewatering of Crude Oil

Pumped crude oil generally contains what is known as formation water. On the one hand, this water can originate from subterranean layers of water in the immediate vicinity of the oil sources. On the other hand, primarily in the case of older wells, water or water vapour has to be injected to allow the oil still present to be pumped at all. This water then also flows out of the well together with the crude oil.

 

Once the oil has been separated, the product is called “produced water”. In the United States, for example, the quantity of produced water is some eight times greater than the volume of oil pumped. This makes it even clearer that this oil-polluted water represents a considerable hazard to the environment. At the same time, the crude oil has to have the water and salts removed from it, otherwise it cannot be processed by the refineries.

 

GEA Westfalia Separator has developed a process by means of which both tasks can be performed in the optimum manner in one overall process.

 

Stringent regulations mean that produced water has to be treated before being discharged into the sea such that, depending on region, its residual oil content is between 15 ppm and 40 ppm. The industry places completely different requirements on the crude oil: the majority of water, solids and water-soluble salts must be removed from the oil before it is processed into fuels and other products, otherwise refinery equipment may be damaged.

 

With GEA Westfalia Separator, both problems are solved in a single overall process. Following static separation of the pumped flow into oil-containing water and wet crude oil, clarifiers reliably separate off the unwanted substances in each case. Of particular interest are centrifugal dewatering systems for crude oils of high density (API 17 and heavier), as conventional static and electrostatic systems do not achieve satisfactory results here.