Hydraulic Fracturing “Fracking” By: Brett JamesHonors Ecology Fall 2011
What Is Hydraulic Fracturing ?• Hydraulic Fracturing is the use of fluids and material to create or restore small fractures in rock in order to stimulate production from new and existing oil and gas wells.• Wells are primarily vertical. 2,000-10,000 ft. deep, with some much deeper.• Fracking occurs horizontally at the bottom of the well.
How Does It Work ?• Most permeable rocks (shales) are found from just below the surface, to as far as tens of thousands of feet in depth.• Shales often hold large quantities of oils and natural gas
How Does It Work ?• After a hole (Wellbore) is drilled, a solution composed of 98-99.5% water and sand is pumped into the cavity• With enough Pressure, surrounding rock material begins to crack or “fracture”
How Does It Work ?• Water-Sand solution provides many things: - Pressure for fracture - Proppant (Supports) - Friction Reducers (50-60%) - Anti-Bacteria - Anti-Iron/Carbonates
How Does It Work ?• Once water is removed, gas collects easily in each fractured zone.• http://www.youtube.com/watch?v=7ned5L04 o8w&feature=related
Where Is “Fracking” Being Used ?• Australia• France• Canada• Great Britain• New Zealand• South Africa• Oklahoma, Texas, Wyoming, Colorado, New Mexico, Louisiana, Arkansas, California, and in the Northeast.
Where is “Fracking” Being Used ?
Benefits• Primarily Economic – Restores older wells – Increases rate of extraction – Taps into shales – Increase in jobs locally – Provides low-cost heating for natural gas users – Provides low cost electricity
Potential Consequences ?• Many potential health concerns – Contamination of ground water – Local air quality – Carcinogens & toxins (methanoyl, benzene, lead, boric acid).• Environmental – Use of fresh water – Injecting chemicals into the ground
Potential Consequences ?• Earthquakes ?
Fracturing and Earthquakes• Rock Fracturing does NOT cause quakes• Millions of water solutions, both fresh or waste water, cause quakes• Water pushes rocks apart, causing rocks to move past one another• Dry sand vs saturated sand
Recent Earthquakes• Oklahoma, 11/5/2011• Magnitude 5.6, with 30 or more weaker aftershocks• 1952, 5.5 magnitude• Increase in fracking near an inactive geologic fault line
Recent Earthquakes• Mineral, Va, 8/24/2011• Magnitude 5.8• So rare, that geologists estimate only 6 more similar events in the next 10,000 years.• Near 3 inactive faults.
Recent Earthquakes• Arkansas, August-October 2011• Sometimes up to 20 small tremors in one day!• Increase in tremors since September 2010, when 4 new wells began hydraulic fracturing.
Recent Earthquakes• United Kingdom, April/May 2011• Two separate 2.3 magnitude earthquakes• Occurred 2km below the surface.• "Most likely, the repeated seismicity was induced by direct injection of fluid into the fault zone.“ - Geomechanical Study of Bowland Shale Seismicity
UK Earthquakes• http://www.youtube.com/watch?v=lo2WG18f w44
Is There A Connection ?• There is an increasing correlation between minor earthquakes and fracking• Fracturing has reactivated or created more activity at some faults (Arkansas)• Hard to explain larger earthquakes (Oklahoma)
Is There A Connection ?• Arkansas tremors dropped by 2/3’s once Arkansas Oil and Gas Commission banned fracking in the area.• West Virginia saw a massive reduction in quakes after it’s commission called for reduced salt- water injection into bedrock.• In Dallas/Ft. Worth, SMU recorded quakes immediately after fracking began in 2008, and stopped recording quakes after fracking stopped in 2009.
What Do YOU think ?• France has already banned hydraulic Fracturing• South Africa/Australia have prevented the creating of new fracking wells, but have kept older wells active.• If minor earthquakes are caused by fracking, should it be allowed ? Even with the jobs and resources the process provides ?