Hydraulic fracturing or “Fracking”

Truth about Fracking, Chris Mooney, Scientific American, November 2011

Information from:

• Fact-Based Regulation for Environmental Protection in Shale Gas Development: A report by the Energy Institute, UT, Austin– “The overall approach of the initiative was to

develop a solid foundation for fact-based regulation by:

– assessing media coverage and public attitudes, – reviewing scientific investigations of

environmental impacts, and – summarizing applicable state regulations and

regulatory enforcement.”

Information from: • The Truth About Fracking, Chris Mooney,

Scientific American, November 2011• Methane Contamination of Drinking Water

Accompanying Gas-well Drilling and Hydraulic Fracturing, Stephen G. Osborn, Avner Vengosh, Nathaniel R. Warner, and Robert B. Jackson, Proceedings of the National Academy of Sciences, May 17, 2011

• US Energy Information Administration (http://205.254.135.7/energy_in_brief/about_shale_gas.cfm)

• http://www.epa.gov/cleanenergy/energy-and-you/affect/natural-gas.html

Natural Gas: Clean Energy?Natural gas power plants produce:•half as much CO2 (greenhouse gas)

•less than a third as much nitrogen oxides (create ground level ozone), •and one percent as much sulfur oxides (causes acid rain)Compared to the average air emissions from coal-fired power plantsHowever, natural gas (methane) is about 70 times more powerful than CO2 as a greenhouse gas

Shale gas production• Conventional oil and gas exploration and

production involves porous and permeable reservoir rocks

• Shale gas production directly involves the source rock (porous but impermeable)

• This was not economically feasible before the advent of horizontal drilling and hydraulic fracturing (fracking) technologies

• Current estimate of shale gas resource: 862 trillion cubit feet (TCF) in continental US

• Recoverable using currently available technology: 827 TCF (industry claims)

• Currently consumed in US: 23 TCF/year• Currently produced in US: 20 TCF/year

One TCF of natural gas is enough to heat 15 million homes for 1 year, generate 100 billion kilowatt-hours of electricity, or fuel 12 million natural-gas-fired vehicles for 1 year. (Source: EIA)

http://www.netl.doe.gov/technologies/oil-gas/publications/brochures/Shale_Gas_March_2011.pdf

http://205.254.135.7/energy_in_brief/about_shale_gas.cfm

ftp://ftp.eia.doe.gov/natgas/usshaleplays.pdf

Northeast: primarily the Marcellus (63%)

Gulf Coast: Haynesville, Eagle Ford (13%)Southwest: Barnett and

Barnett-Woodford (10%)

Mid-Continent: Fayetteville, Woodford (8%)

Rocky Mountain: primarily Mancos and Lewis (6%)

Fracking technology

• Hydraulic fracturing = Chemically treated water and sand under high pressure to fracture rocks (increase permeability)

• Has been used since 1940’s in vertical wells to stimulate production in existing oil/gas wells

• This technology has been combined with horizontal drilling and fracturing in the 1980’s and 90’s

Potential Environmental Impacts of Shale Gas Development

• Drill Pad Construction and Operation• Groundwater Contamination (most controversial

issue)• Hydraulic Fracturing and Flowback Water

Management (another controversial issue)• Blowouts and House Explosions• Water Consumption and Supply• Spill Management and Surface Water Protection• Small earthquakes from injecting fracking

wastewaters in deep underground reservoirs (Youngstown, Ohio, December 31, 2011, 2.7 and 4.0 Richter Magnitude earthquakes possibly caused by injection fluids)

Scientific American, November 2011

Scientific American, November 2011

The controversyissue 1: Migration of fracture fluids

(and/or methane) to aquifers • Industry says: No

evidence of fracturing fluids found in aquifers

• It is highly unlikely/improbable that fracture fluids can migrate through the overlying rocks to the aquifers

• It is not yet really understood how multiple fractures from repeated fracking operations in the same site may interact

• How fractures may interact with old oil wells, and pre-existing natural faults and fractures

Thermogenic methane contamination near hydraulic fracturing operations

PNAS, May 2011

However, this study found no evidence for contamination of the shallow wells near active drilling sites from deep brines and/or fracturing fluids.

Leakage from wells seem to be the most likely cause for groundwater contamination by thermogenic methane and/or fracture fluids.Can be :•Through the hole between the rock formation and cement •Through the gap between the cement and steel casing•Through leaky/cracked gas-well casing

The controversyissue 2: Groundwater contamination from

additives in fracture fluids • Industry says: fracturing

fluids contain 90% water, 9.5% sand or other particles, and less than 1% additives

• ALL these additives are used in common household products. Exposure is not unique to fracking chemicals

• Additives may include 2-BE (destroys red blood cells among other effects), naphthalene (probable carcinogen), and benzene (known carcinogen)

• 15,000 – 60,000 gallons of additives are needed for a single lateral

Flowback and Produced Water Management

• After fracking, the injected fluid plus water from the shale is brought back up on surface for treatment, recycling, and/or disposal

• This water contains saline water from the shale formation, fracking fluids, and arsenic

• This can cause surface water contamination if not disposed/managed properly (spills)

• Primarily disposed in injection wells (can cause earthquakes by lubricating faults)

• Recycling and reusing this water will cut down the water consumed by fracking (see next slide)

Water use for fracking operations

• Typically 4 to 6 million gallons per well “EPA estimated that if 35,000 wells are

hydraulically fractured annually in the US, the amount of water consumed would be equivalent to that used by 5 million people.”

• Source of water used from fracking operations varies, and is not well documented or monitored