Strip oil from produced water for reuse in EOR campaign

A major oil operator was generating 15,000 bbl/d of produced water during heavy oil production in its operation in southeastern Europe. The produced water included diluents that emulsified the oil, leaving high concentrations of asphaltenes and diesel-range organics with total suspended solids (TSS) concentrations up to 800 ppm. Oil, grease, and emulsion content varied greatly during production. The corrosive nature of the produced water necessitated the use of 316 stainless steel construction material on the project. The operator sought a solution that would enable filtering the water to less than 10 ppm of contaminants, which would allow reinjection of the produced water for reuse in the operation. 

Perform robust three-stage advanced media technology solution

Schlumberger recommended the operator run advanced media polisher oil-free water technology to remove inlet oil from the original 2,500 ppm to less than 10 ppm. The system included three stages of decontamination:

• The primary stage included an oil-water separator to coalesce and recover a wide range of heavy oil droplets ranging from 100 to 2,500 ppm.
• The secondary stage used the advanced regenerative water treatment media to treat dispersed and emulsified heavy oil present at 1,000 ppm and TSS up to 800 ppm.
• The tertiary stage used the advanced media polisher filters to remove the trace contamination of oil to less than 10 ppm.

The advanced media technology system included automatic controls to respond to fluctuations in flow rates and pressure drop. Because of the risk of corrosion posed by the produced water, anodic protection was used to maintain system integrity.

Achieved 2-ppm water filtration for reinjection

By using advanced media technology, the operator effectively and consistently removed TSS from the produced water to achieve a 2-ppm level for reinjection use—lower than the 10-ppm level that was requested. This performance was well maintained during large fluctuations of asphaltene-laden and diesel-range organics in free, dispersed, and emulsified phases. Inlet oil levels varied between 100 and 2,500 ppm, and the system outlet showed oil to be reduced to 10 ppm or less throughout its use.