Presentation on theme: "Fracking 101. What is fracking? This is short for “hydrofracturing.” This is an old technique for increasing oil production from worked-out oil wells,"— Presentation transcript:
What is fracking? This is short for “hydrofracturing.” This is an old technique for increasing oil production from worked-out oil wells, but a new technique for obtaining methane (natural gas).
Fossil fuels Coal—essentially CH 0.8 The most carbon per unit of energy. Oil—essentially CH 2 Intermediate amount of carbon per unit of energy. Gas—CH 4 The least carbon per unit of energy. This is surely preferable to the other fossil fuels for this reason.
Natural Gas: Clean Energy? Natural gas power plants produce: half as much CO 2 (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 plants However, natural gas (methane) is about 70 times more powerful than CO 2 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)
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)
The controversy issue 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
The controversy issue 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
“The increase over the nation’s midsection has gotten steeper since 2009, due to more quakes in a variety of oil and gas production areas, including some in Arkansas and Oklahoma, the researchers say. “Fracking at fault? Probably not “It’s not clear how the earthquake rates might be related to oil and gas production, the study authors said. They note that others have linked earthquakes to injecting huge amounts of leftover wastewater deep into the earth.”