Enhanced oil recovery

Jon Gluyas, Durham University, Enhanced oil recovery using CO2 -- The North Sea, an opportunity?

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• published: 22 Feb 2013
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Wednesday, September 15, 2010 London The Geological Society Carbon dioxide has long been used to enhance the recovery (EOR) of oil from fields within West Texas. Published data indicate that the process can recover 10% of initial oil in place on top of that already won from primary depletion and secondary water flood. Experience has shown that 1 tonne of injected CO2 can deliver 2.5 to 5bbl oil. Typical project lengths are in the order of 15 to 20 years. For the UK we have no experience of using CO2 for EOR in the North Sea -- although in the late 1970s BP did a small trial at one of their onshore fields and, of course, Statoil has 10 years worth of experience on the NOCS gained from the Sleipner project, in which separated CO2 is being injected into a deep aquifer. Published figures from the UK's Department of Energy & Climate Change indicate that the ultimate UK oil reserve, using the current primary and secondary recovery, is in the order of 30 billion barrels. Data on the initial oil in place is less readily available but we can calculate such a figure from the published information on recovery factor, which is around 45%. From this we can estimate the STOIIP on the UKCS to be around 67 billion barrels. Using CO2-EOR an additional 10% of recovered STOIIP equates to 6.7 billion barrels. Given that the West Texas analogue may not be good and a number of the fields may not be suitable for this method of EOR either for technical or logistical reasons let us more than halve the figure and suggest that it may be possible to recover an additional 3 billion barrels of oil from the major UK North Sea fields. That such a volume of oil could deliver substantial fillip to the UK Treasury at a time of acute need is without doubt but this is only part of the story. A CO2-EOR industry would also enable the processes of CO2 capture, transport, injection and monitoring to be properly developed and the infrastructure to be constructed -- ready for full CCS. The UK could lead the world in such offshore technology and then export such know-how. And the source of CO2? Take every molecule of industrially produced CO2 from Aberdeen to Hull and there is just about enough to satisfy the potential requirements. The technical difficulties and commercial hurdles for the first such North Sea CO2-EOR projects are huge; so too are the rewards.