Enhanced oil recovery using CO2
The North Sea, an Opportunity?
Jon Gluyas
Durham Energy Institute, UK
Carbon Capture & Storage,
Geological Society of London
- 15th September 2010 -
Outline
•
•
•
•
•
•
•
CO2-EOR – a long history
UK oil reserves
UKCS – the EOR prize
UK industrial CO2 production
Project timing
Costing the earth & saving the planet
The CO2-EOR heritage
CO2-EOR – A Long History
• Initiated 1970s in
response to oil crisis
• Texas at forefront of
technology & leads the
way today
• Permian Basin in NW
Texas is the primary
injection area
• 1000s km 32” pipeline &
associated infrastructure
developed
• Natural & anthropogenic
CO2 sources used
CO2-EOR – Technology
• Water Alternating Gas (WAG)
– CO2 injected to swell oil and increase fluidity
– H2O injection to displace oil to production wells
• Gravity Stable Gas Injection (GSGI)
– CO2 injected at field crest
– Stabilising pressure and promoting gravity drainage
• Miscible flood – critical CO2 dissolved in oil
– swelling oil, viscosity reduced surface tension reduced
• Immiscible CO2 displacement
– Partial dissolution in oil may reduce viscosity substantially
Schematic WAG
http://www.netl.doe.gov/scngo/Petroleum/publications/eordrawings/eordraw.html
How much additional
recovery?
• West Texas 4-12% of STOIIP (observed)
– 60+ projects (~100 world wide)
• US DOE 7-14% of STOIIP (calculated)
• Institute for Energy (Netherlands) 9-18%
STOIIP of UK, Norwegian & Danish fields
(calculated)
How much CO2 is used?
• 0.1 to 0.45 pore volumes injected
• Typically 1 (net*) tonne of CO2 injected
delivers 2.5 to 5 bbl oil (average 3 bbl)
• Tapered WAG (decreasing CO2 volumes)
most effective
*Net = total injected - recycled
UK Oil Fields
From Gluyas & Hichens, 2003
Viking
Graben
Moray Firth &
Central N Sea
UK Offshore Oil Reserve
Proven
Cumulative
Oil
Production in
millions
tonnes
(bnbbl)
3315
(24.9)
Estimated
Ultimate
recovery in
millions
tonnes
(bnbbl)
3723
(27.9)
Probable
P+P
Possible
Maximum
361
(2.7)
4048
(30.4)
360
(2.7)
4444
(33.3)
https://www.og.decc.gov.uk/information/bb_updates/chapters/Table4_3.htm
UKCS Recovery Factors ~45%
• High End - Piper – recovery factor >70%
• Low End - Lyell – recovery factor ~5%
Jayasekera &
Goodyear SPE 75171
UKCS & West Texas Oil Fields
UKCS
• Sandstones
• Most > 2.7 km deep
• Most > 90ºC
• Light oil ~35-40API
• Typically high quality
(permeability – 100s mD)
• Line drive water floods for
secondary recovery
• Low well density
2nd Development Board Meeting
West Texas
• Sandstones & dolomites
• 1.2 to 1.8 km deep
• 15-60ºC
• Light oil 30-42API
• Typically low quality
(permeability 4-16 mD)
• Pattern floods
l
• High well density
UKCS vs West Texas
• West Texas – incremental oil recovery 4-12% of
STOIIP
• CO2 is expected to be miscible (or nearly so)
with current conditions in the UKCS oil
reservoirs
• UKCS fields more permeable and at higher
temperature than those in West Texas – both
factors may favour the North Sea
From Goodyear et al, IEA EOR Caracas 2002
UKCS – The Prize
• Assuming UKCS:
– Reserve of 30,000mmbbl
– STOIIP 30,000/0.45 = 67,000mmbbl
• From West Texas 4-12% additional recovery of STOIIP
– Yields 2,700 – 8,000 mmbbl technical reserves
– Requiring ~1 t CO2 per 3bbl*
• For ~3,000 mmbbl, ~1,000 Mt CO2 required
*range 2.5 to 5 bbl/tonne
UK Industrial CO2 production 2007
• Scotland
19mm tonnes
• North East 21mm tonnes
• Yorkshire 27mm tonnes
& Humberside
UK oil province
100km
http://www.decc.gov.uk/en/content/cms/statistics/climate_change/climate_change.aspx
Supply & Demand
• Assuming all industrial CO2 from the
eastern UK could be available for CO2EOR yields 60-70mm tonnes per annum
• Over a 15-25 year period (ie typical CO2EOR project length) this would use 1
billion tonnes CO2 …. the quantity required
to optimise CO2-EOR in the North Sea
Are UK Oil Fields Ready For
CO2-EOR?
Arbroath
Maureen
Claymore
Ninian
The Time is Right (but don’t wait)
UKCS Shrinking Infrastructure
Jayasekera & Goodyear SPE 75171
UK Security
of Supply
Shortfall in 2010
~15 mm tonnes
Equivalent to
~300,000 bopd
Equivalent to
Initiating ~1/3
potential CO2EOR projects
DECC publication 2008
Costing the Earth?
• For the North Sea
– There is no CO2 infrastructure
– There is no ‘ready’ source of CO2
– The first project will be an enormous commitment
• But in 2003
–
–
–
–
–
WoS to Magnus pipeline laid
~200 miles long
CH4 for WAG
50mmbbl additional reserves
3+ years extra field life
Saving the Planet
• 1bbl of oil contains ≡ 0.42 t CO2 after
combustion
• 1bbl produced by CO2-EOR requires
between 0.4 and 0.2 t CO2
• At best – the process is carbon neutral
• At worst – the process is halving
emissions
CO2-EOR Heritage
• The CO2 production from
eastern UK could ‘power’
CO2-EOR in the North Sea
for 10-15 years per project,
over ~30 year period
• It could deliver:
– Improved security of oil supply
– Infrastructure usable for carbon
capture
– Increased tax revenues over
current projections
Deep aquifer storage area