PROCESSING
Separation Plant Life
Extension
Increased water cut from production wells is a growing problem for Middle East oil companies. Jeroen
Bergman of Frames shows how innovations in retrofit water treatment process design are coming to the aid
of producers.
I
n 2015 the International Association of
Oil and Gas Producers conducted a survey
of 31 oil companies in 60 countries looking
at, amongst other things, the levels of water
in every tonne of oil produced. The results
confirmed a worrying trend – levels of water
up to 92% with 8% oil were reported in the
Middle East and North America. Europe is
coping with average 78% water and 22% oil.
3D model of Onshore Produded Water Treatment Facility.
Oil and gas reservoirs normally contain
amounts of water, oil, solids, condensates
and gas. Produced water is the industry term
given to reservoir water. When oil and gas
are processed, produced water is separated
and pumped back into the reservoir in
order to maintain the correct pressure in the
well. Alternatively, the water is reinjected
in disposal wells or evaporation ponds.
Both cases are covered by strict regulations,
aimed at preventing well contamination and
environmental pollution.
Higher water levels
The causes of higher water levels include
ageing wells and depleted oil and gas
reservoirs, tie-in of extra wells, and enhanced
oil recovery
processes that rely on injecting high levels of
water. Water separation trains are normally
designed for the expected water level.
However, over time the conditions for the
separation train will change as the well’s water
cut increases.
These increases can be accommodated by
the separation train within limits, however,
handling and treatment of produced water up
to the required quality levels will become an
increasing cost factor in the total Life Cycle
Cost of produced water processing. When
the increase becomes too large, action has to
be taken. Failing to do so will result in water
being carried downstream causing poor
separation performance.
Frames Design & Technology
Frames Skid-mounted Flotation Package.
Over the years’ Frames has developed a range
water treatment packages to reduce the oil-in-
water content typically from 2000 ppmv down
to 20 ppmv. These include plate coalescers and
hydrocyclones for bulk oil removal followed
by a hydraulic or mechanical flotation unit for
removal of remaining small oil droplets. The
Frames Produced Water Treatment packages