10 år med skifergas i Canada
- hvad kan vi lære?
Per Kent Pedersen
Department of Geoscience
University of Calgary
Skifergas: Trussel eller mulighed for Danmark, Ingeniørforeningen Danmark, May 13, 2013
Western Canada Sedimentary Basin
NWT
Up to 7 km thick PhanerozoicAlberta
strata
+730,000
Wellsin 2012
15,231
wells drilled
or 26,645,125m ≈ 27,000km
or ~2 times through the Earth
Saskatchewan
Manitoba
British Columbia
Montana
North Dakota
100 km
North American Gas and Oil Shale Plays
Next 5 – 10 years
- ~100,000 wells
- 1 – 2 million hydraulic fracks
http://gcep.stanford.edu/pdfs/2wh9Q1Alh3q2zMOQRKD4MQ/MarkZoback_ShaleGas101.pdf
Fracking
• High-pressure water with sand and additives is
injected into the reservoir to open or create fractures.
• Newly created fractures are propped open by injected
sand increasing permeability and allowing gas to be
produced.
http://www.fossil.energy.gov/programs/oilgas/shalegas/hydraulicfracturing.html
Fracking History
• +100 years of fracking
– Old dynamite trick
• Canada +60 years of large scale
hydraulic fracing history in vertical
wells
– +175,000 oil and gas wells have been
hydraulically fractured in Canada
– From 250 to 4000 m depth
– No evidence of drinking water
contamination
– One case being investigated if fracking
of coal seam at 250 m depth entered
ground water
Fracking History
• Horizontal
hydraulic
fractured wells
• Improved
technology lead
to large
increase in use
since 2003
www.NEB.ca
2012 Horizontal Wells in Western Canada
Alberta
Deloitte 2013
Saskatchewan
Manitoba
British Columbia
Modified from Dave Russum, Deloitte 2013
•
•
•
•
•
Montney Shale Play
300 by 130 km fairway
300 m thick at 1.5-3 km
700 TCF of gas in place
200-350 BCF/mile2 gas
+2000 HZ multistage
fracked wells
BMO 2011
BMO 2011
BMO 2011
Montney Shale Play
• Smaller and larger
number of frack stages
• Fresh water consumption
decreased
Montney Fm
– Waste water used
– recycling
Montney Fm
BMO 2011
Canadian Discovery 2013
Montney Shale Play
• Evolution from single
well pads to multi-well
from each pad
– Up to 18 wells/pad
• Longer reach wells
– From 1.6 to 3.2km long
horizontal legs
– One pad drains an area
of up to 10 km2
• Central facilities
– Drilling and completion
– Production and pipelines
5 km
Geometry of Induced Fractures
1200 m
http://www.csur.com
Geometry of Induced Fractures
Ground
Surface
Surficial, freshwater aquifer
depth
Hydraulically-fractured
shale
Depth of
horizontal well
trajectory
- data from 1000’s of shale gas hydraulic fracturing treatments
Fisher and Warpinski, 2011, SPE 145949
Kevin, Fisher,,American Oil and Gas Reporter, July 2010
Fracturing of Existing Faults
• Induced fractures
commonly
contained within a
few hundred
meters around the
well bore
Duhault (2012)
BC Government Report Investigating
Fracturing Induced Earthquakes
Horn River Basin study
• 8000 hydraulic fracture
treatments were completed with
no associated seismicity
• The NRCan seismicity was caused
by hydraulic fracturing near preexisting faults
•Report
NoneRecommendations
caused any injury, property
or posed
anyofrisk
• damage,
Improve the
accuracy
thetoNRCan Network
or thedata
environment
• public
Reviewsafety
geological
to identify pre-existing faulting
Establish
seismicity
monitoring reporting procedures and
•• All
eventsinduced
confined
to the target
requirements
shales,
no effects on shallow
• aquifers
Install ground
sensors near populated area
were motion
identified
• Deploy portable high density arrays near frac operations
• Require the submission of microseismic reports
• Study the relationship between hydraulic fracture parameters and seismicity
Gas in Shallow Aquifers
• Gas is common in shallow aquifers
• Can form large economic accumulations
– Shallow gas
– Coal Bed Methane
– Outcropping organic rich shales
• Upper Devonian Antrim Shale in the Michigan Basin
• Commonly Biogenic in origin
Osbourn et al., 2011, Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.1100682108
Canadian Association of Petroleum
Producers Recommendations 2012
Industry through CAPP has recommended:
• Hydraulic Fracturing Operating Practices
1.
2.
3.
4.
5.
6.
Fracturing fluid additive disclosure
Fracturing fluid additive risk management
Baseline groundwater testing
Wellbore construction
Water sourcing and reuse
Fluid handling, transport and disposal
Gaining the Public Thrusts
• Public Access to data allows independent
review and research
– Drilling information
– Cores and core analysis data
– Well logs
– Pipeline locations, etc.
– Fracking water composition
• http://fracfocus.ca/
– Production data
• Gas, oil, water rates
• Composition