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Why Is Shale Gas Development “Unconventional”. Because it requires 3 technologies only recently combined to make gas production from shales technically and economically feasible. Directional drilling : needed to access a thin layer of shale with long laterals.
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Why Is Shale Gas Development“Unconventional” • Because it requires 3 technologies only recently combined to make gas production from shales technically and economically feasible. • Directional drilling: needed to access a thin layer of shale with long laterals. • High frac fluid volumes: needed to stimulate gas release from many existing fractures. • Slickwater: needed to control the amount of power needed to pump large volumes of frac fluids, at high pressures, quickly, over long distances, through small diameter casing. CHE_Nov 9, 2010_Ingraffea
High Volume, SlickwaterFracing from Long Laterals: The Concept Not to scale ~ 5000 feet Cap rock The Lateral ~ 100 feet Pay zone Cap rock CHE_Nov 9, 2010_Ingraffea
J2 J1 Early Joints at Taughannock Falls Gas Producing Shales are Heavily Fractured Naturally Geneseo-Burket (Devonian black shale) Taughannock Falls State Park, Trumansburg, N.Y. Photo Courtesy T. Engelder CHE_Nov 9, 2010_Ingraffea
Why Is Slickwater, High-Volume Fracing from Long Laterals a Higher Risk to Human Health? • Requires much higher well density, many wells per square mile. • Requires much more industrial development over large areas, heavy equipment operating 24/7/365. • Requires much higher volumes of fracing fluid, millions of gallons per well. • Produces much higher volumes of waste fluids and solids containing hazardous materials: frac fluid chemicals, heavy metals, NORMS. • Produces much higher volumes of fugitive emissions of methane. CHE_Nov 9, 2010_Ingraffea
Example: Dallas/Fort Worth Airport Property, Barnett Shale Play • 53 pads on 18,076 acres • Each red line is a well • Almost complete • coverage • Patchwork, mostly ideal • units • One developer CHE_Nov 9, 2010_Ingraffea
Ideal Arrangement of Spacing Units CHE_Nov 9, 2010_Ingraffea
Why Is Slickwater, High-Volume Fracing from Long Laterals a Higher Risk to Human Health? • As number of wells and volumes of waste increase, probability of accidental releases of hazardous materials into air and groundwater increases. • Cumulative effects on air and water from purposeful emissions into the atmosphere and releases into groundwater are unknown. • Increased production and burning of natural gas and its liquid companions (e.g. ethane, propane, butane) increases emission of GHG’s. CHE_Nov 9, 2010_Ingraffea