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Environmental Impactsand Geophysical Risks of
Shale-gas Development
Chris J.H. Hartnady
Umvoto Africa (Pty) Ltd,Muizenberg
http://www.umvoto.com
SHALE Southern AfricaCape Town, 26-27 March 2012
http://www.umvoto.com/http://www.umvoto.com/ -
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Presentation overview
Shale-gas development Global perspective
Era of Extreme energy
Environmental impacts
Landscape degradation Water consumption / resource depletion
Surface-water contamination
Groundwater contamination
Geophysical risks Triggered earthquakes
Greenhouse-gas (fugitive) emissions
Energy-cost and other considerations
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Natural gas in US: shale a game-changer?
Shale gasgame-changer
from 2005
M. King Hubbert1903-1989
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EIA 2011 resources assessment
1275862
774
681
485396
388
SA ranked fifth in world,
but ?
TCF = trillion cubic feetFigures refer to
technically recoverableresource (TRR),
not economically recoverablereserve
But note trend in TRR for Marcellus shale:489 TCF (Engelder 2009) 262 TCF (DOE 2009) 84 TCF [P50] or 43 TCF [P95] (USGS, 2011)
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Geological setting of natural gas
Why target thedepleted
source?
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Era of extreme energy
humanity has embarked on the era of extremeenergy, where there are no simple solutions. Theinexpensive, high-yield fossil fuels that powered theindustrial revolution are dwindling, and all of them
emit dangerous levels of greenhouse gases. Whileenormous amounts of natural gas, oil, and coalremain, the portions of those fuels that werecheapest and easiest to produce are now mostly
gone, and producing remaining reserves willentail spiraling investment costs andenvironmental risks.
Richard Heinberg, fellow of Post-Carbon Institute, 2011
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Shale gas impacts and risks
Surface impacts of road and drill pad construction and the requirementfor hundreds of truck trips for each well
Very high water consumption potentially problematic, particularly inarid areas
Contamination of surface water through improper disposal of toxicproduced drilling fluids containing salts, radioactive elements, and othertoxins
Contamination of groundwater directly through hydraulic fracturing andas a result of compromised cementing jobs in near-surface casing
Induced earthquakes through fluid injectionboth during the hydraulicfracturing process and during the disposal of waste fluid through injectionwells
Higher full-cycle greenhouse gas (GHG) emissions
J. David Hughes, 2011.Will Natural Gas fuelAmerica in the 21st Century?Post Carbon Institute, Santa Rosa,CA, USA, 64 pp.
http://www.postcarbon.org/report/331901-report-will-natural-gas-fuel-america
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Environmental Impacts
Hughes (2011) identifies 6 main concerns,including 4 environmental risks:
Surface impacts of road/drillpad/pipeline infrastructure construction,
including 100s to 1000s of truck trips
Very high water consumption, affectingresource quantity, intensifying allocationscompetition and hastening depletion
Contamination of surface water and
groundwater through improper disposal offlowback and produced water
Contamination of groundwater throughhydraulic fracturing, methane migration andcompromised surface casing grouting
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Landscape degradation
Destruction andloss of aestheticsense of place
Industrializationof ruralenvironment
Traffic and
noise pollution
Example of Eolia gas field, Oklahoma
June 2003 April 2008 change
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Water resource competition / depletion
Exploration phase = 2000-9000 m3/well(Shell estimate)
48 000-216 000 m3 over all 3 Karoo areas (24wells)
Require establishment of 40 l/s wellfield to deliversame amount of groundwater in 2-month period?
USA experience:
Marcellus = 12 000, Barnett = 14 000 wells
Similar production in Karoo = ~10 000 wells?
Production phase = 5000-20 000 m3/well
50-200 Mm3 water consumption
Annual groundwater demand in 3 areas = 47 Mm3
Future technology: 50 well pads x 30 wells = 1500
wells = 7.5-30 Mm3 ?
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Produced/flowback water = major qualityhazard Highly saline, acid & corrosive (from pyrite reaction),
radioactive (thorium, uranium, radium), toxic metals(arsenic, mercury), fracking fluid additives
Requires disposal or recycling Transport to wastewater treatment works where
treated and released back to surface streams
Injected into depleted gas fields or deep strata
Recycled and re-used as fracking fluid
Spread on roads for dust suppression
Stored in evaporation pits
Spills hazard during drilling, leakage and overflow from storage
ponds/evaporation pits, pipeline and casing breakage
Surface-water contamination
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Groundwater contamination
Fracking fluids Slickwater = 99% water and proppant (sand, ceramics,
bauxite) 1% fracking additives = hydrochloric acid,biocides, dimethyl formanides, sodium carbonate,ethylene glycol, isopropanol
Do these fluids pose a significant risk to subsurfacecontamination via fracking procedure?
Cross contamination of aquifers Drilling-induced fractures crossing groundwater flowpaths
Casing flaws/failure
Methane contamination from Marcellus Shale(Osborn et al., 2011) Methane (thermogenic origin) 17 times higher in gas
extraction areas, than methane (biogenic origin) in non-extraction areas
Not regulated, but asphyxiation/explosion hazard
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PNAS study (April 2011)
Proceedings of the U.S.National Academy ofScience, online edition
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Well casing and cement failure
Cement has little tensile strength of itsown and fails in tension before lendingsignificant support to the casing. Theassumption of no contact between thecement sheath and borehole is unrealistic,
but illustrates the dangers to crackingthe cement sheath by generating a highinternal pressure in casing, especiallyduring casing pressure tests aftercementing.
(Fleckenstein et al., 2005, AADE-05-NTCE-14; American Association of DrillingEngineers National Technical Conference,Houston, Texas)
Achilles heel at the casing shoe?
How gasgets to
surface byunplanned
route
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Hazards of unconventional
BP Macondowell blow-outin deepwater
Gulf of Mexico Caused by
loss of controlover gas influx
into wellthrough faultycasing andcement seal
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Geophysical risks
Hughes (2011) identifies 2 maingeophysical risks:
Induced earthquakes through fluidinjection during fracking andsequestration of wastewater
Higher full-cycle greenhouse gasemissions
Tulbagh 1969
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In the recent news
Is there a connection to gas-shale fracking?
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Oklahoma epicentres (2009-2011)
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2010-2011 activity near Wilzetta Fault
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Recent pad developments
Google Earthchangeanalysis
1995 Feb 08
2008 Apr 15
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Ohio earthquakes
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Ohio earthquake outcome
Earthquakes last year in Ohio were probablycaused by wastewater from oil and natural-gasdrilling injected into a disposal well, andregulations are needed to address concernabout seismic activity, a state report said.
The Ohio Department of Natural Resourcestoday proposed creating rules for fluidtransportation and disposal that it said would be
"among the nation's toughest," includingbanning drilling into some rock formationsand requiring geological reviews before wellsare approved.
Extract from media report by Mark Niquette, Bloomberg, Mar 9, 2012
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Karoo earthquakes!?
2011 May 14 16:10 SAST
Local magnitude (ML) 4.1
M6.2;1809
M6.3;1969
M7.3;~10.6k BP
USGS
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Lithospheric stress patterns
Dynamic model ofvertical integrated stressanomaly (VISA)
Karoo within N part of
Cape Stress Province(Hartnady, 1998;Wegener Stress
Anomaly of Andreoli)
Reflects high crustalstresses generated bybreak-up of Africabetween Nubia (NU)and Somalia (SO) plates
from Bird, Liu and Rucker, 2008
NU
SO
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Economics of shale gas
With mounting evidence of the environmental and
human health risks of shale gas production,environmental groups are rightfully questioning the
cleanliness of shale gas. But if these groups focus theirarguments only on the contamination of ground watersupplies of shale gas without at the same timequestioning the economics of shale gas drilling, they willhave helped set up conditions for a political battle that
could undermine their own influence and credibility.(cont.)
Richard HeinbergFrom preface to J. David Hughes, 2011.Will Natural Gas fuel America in the 21stCentury?
Post Carbon Institute, Santa Rosa, CA, USA, 64 pp.
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Energy-cost considerations
From Dale et al., 2011
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Financial considerations?
In order to access Wall Street capital, (shale gas)producers have needed to demonstrate that they arebeing successful in exercising a strategy foraggressive wealth creation. That means aggressively
buying acreage and drilling wells. Exercising asuccessful strategy often creates a vicious cyclemore acreage and wells equals increased productionand depressed prices. This cycle will continue as
long as the music (Wall Street's money) continues toflow. Once that stops, we will see how manyproducers can find a chair in the room. In themeantime, the fun continues!
G. Allen Brooks, 2011. Musings: Imaging the future for the shale gas industry.
Rigzone, (Tue Dec 6, 2011), http://www.rigzone.com/news/article.asp?a_id=11314
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Role of political interests
Political interests traditionally funded by the oil and gas
industries will once again claim that environmentalism isthe only thing standing between Americans and energy
security. And if environmentalists are successful inenacting regulations to minimize the risks of watercontamination without clarity about the full lifecyclegreenhouse gas emissions of natural gas, they may
inadvertently exacerbate the very crisis they are trying toaddress.
Richard HeinbergFrom preface to J. David Hughes, 2011.Will Natural Gas fuel America in the 21stCentury?
Post Carbon Institute, Santa Rosa, CA, USA, 64 pp.
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Council of Scientific Society Presidents:Letter on energy & environment, 14 May 2010
(We) represent the leadership of over 1.4 million scientists in over150 scientific disciplines
The production of natural gas (methane) from shale represents amajor new domestic energy resource that can reduce reliance on
imported crude oil ...(but) is anotherexample where policy haspreceded adequate scientific study. Economic recovery requiresthe drilling of long-reach horizontal wells and the high-pressureinjection of with chemical additives to release the gas through aprocess called hydrofracking. Despite the utilization of millions ofgallons of water and the flow back to the surface of these injected
fluids, hydrofracking is exempted from the Clean Water Act.Exploitation of the Marcellus Shale Formation in the AppalachianBasin, recognised as the largest shale-gas reserve in the U.S., couldoccur across a five state region. Prior, thorough science-basedstudies are required to evaluate the impact of massive shaledevelopment on rural land uses, water supply and quality, andfull-cycle greenhouse gas emissions
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Ultimate energy value proposition?
Area(s) ofexcellentdirectnormal irradiance
(DNI) forconcentratingsolar power(CSP) generation
Shale gas versus CSPThank you
for your
attention!