10 år med skifergas i Canada- hvad kan vi lære?

Per Kent PedersenDepartment of Geoscience

University of Calgary

Skifergas: Trussel eller mulighed for Danmark, Ingeniørforeningen Danmark, May 13, 2013

Western Canada Sedimentary Basin

British Columbia

Alberta

Saskatchewan

MontanaNorth Dakota

+730,000 Wells

Manitoba

100 km

NWT 15,231 wells drilled in 2012or 26,645,125m ≈ 27,000km

or ~2 times through the EarthUp to 7 km thick Phanerozoic strata

North American Gas and Oil Shale Plays

http://gcep.stanford.edu/pdfs/2wh9Q1Alh3q2zMOQRKD4MQ/MarkZoback_ShaleGas101.pdf

Next 5 – 10 years- ~100,000 wells- 1 – 2 million hydraulic fracks

Fracking

http://www.fossil.energy.gov/programs/oilgas/shalegas/hydraulicfracturing.html

• 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.

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

British Columbia

Alberta

Saskatchewan Manitoba

Modified from Dave Russum, Deloitte 2013

Deloitte 2013

• 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

Montney Shale Play

BMO 2011BMO 2011

BMO 2011

• Smaller and larger number of frack stages

• Fresh water consumption decreased– Waste water used– recycling

Montney Fm

Canadian Discovery 2013

Montney Fm

Montney Shale Play

BMO 2011

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

( 6 * 6ROXWLRQV

http://www.csur.com

Geometry of Induced FracturesSurficial, freshwater aquifer

depth

Hydraulically-fracturedshale

Ground Surface

Kevin, Fisher,,American Oil and Gas Reporter, July 2010

Fisher and Warpinski, 2011, SPE 145949

- data from 1000’s of shale gas hydraulic fracturing treatments

Depth of horizontal well trajectory

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

Year

Mag

nitu

de

1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011

5

4.5

4

3.5

3

2.5

2

1.5

1

0.5

0

Color byBasin

Horn River BasinInterior PlainsHorn River Basin study

• 8000 hydraulic fracture treatments were completed with no associated seismicity

• The NRCan seismicity was caused by hydraulic fracturing near pre-existing faults

• None caused any injury, property damage, or posed any risk to public safety or the environment

• All events confined to the target shales, no effects on shallow aquifers were identified

Report Recommendations• Improve the accuracy of the NRCan Network• Review geological data to identify pre-existing faulting• Establish induced seismicity monitoring reporting procedures and

requirements• Install ground motion sensors near populated area• 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. Fracturing fluid additive disclosure2. Fracturing fluid additive risk management3. Baseline groundwater testing4. Wellbore construction5. Water sourcing and reuse6. 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