WK10: Part 4: How does fracking work

Fracking: Accessing Natural Gas

  • Natural gas forms over millions of years from decaying organisms under intense heat and pressure.

  • Hydraulic fracturing (fracking) is a technology used to extract previously inaccessible natural gas.

How Fracking Works

  • Fracking sites can be located anywhere with natural gas deposits.

  • A vertical wellbore is drilled through layers of sediment, typically reaching a depth of 2500-3000 meters.

  • At this depth, horizontal drilling begins, extending about 1.5 kilometers through shale rock formations.

  • A perforating gun creates small holes in the well's casing to access the rock layer.

The Fracking Process

  • Fracking begins 3-4 months after initial drilling.

  • Fracking fluid is pumped into the well at high pressure to crack the shale rock.

  • The fluid is over 90% water with chemical additives:

    • Acids: clear debris and dissolve minerals.

    • Friction-reducing compounds: create slickwater.

    • Disinfectants: prevent bacteria growth.

  • Sand or clay is added to prop open fissures for gas and oil to escape even after pressure release.

Environmental Impact: Water Usage

  • Fracking uses an average of 3 to 6 million gallons of water per well.

  • While significant, this is less than agriculture, power plants, or golf course maintenance.

  • However, it can still have a substantial impact on local water supplies.

Waste Disposal

  • Flow-back liquid containing contaminants (radioactive material, salts, heavy metals, hydrocarbons) comes to the surface.

  • Disposal methods:

    • On-site pits.

    • Deep wells.

    • Off-site water treatment facilities.

  • Recycling flow-back liquid:

    • Increases contamination levels with each use.

Potential Contamination

  • Wells are encased in steel and cement to prevent groundwater contamination.

  • Negligence or accidents can lead to:

    • Fracturing into underground water sources.

    • Hazardous underground seepage and leakage.

    • Inadequate wastewater treatment and disposal.

Seismic Activity

  • Concerns exist about earthquakes and damaged infrastructure due to pressure and wastewater injection.

  • Links between fracking and increased seismic activity raise questions about long-term pressure imbalances.

Air Pollution

  • Burning natural gas emits half the carbon dioxide of coal per unit of energy.

  • However, fracking causes pollution:

    • Methane leaks during drilling and pumping.

    • Methane is a potent greenhouse gas, CO_2}.

  • Some argue methane's impact is low due to its dissipation.

Long-Term Considerations

  • Fracking may detract from the development of cleaner, renewable energy sources.

  • Natural gas is non-renewable.

  • Short-term economic interests in fracking may conflict with addressing global climate change.

Fracking Today

  • Modern fracking has boomed in recent decades due to decreasing natural gas sources, rising costs of non-renewable energies, and advancements in technology.

  • Many countries and regions have banned fracking due to environmental concerns.

  • Fracking has significantly impacted the global energy landscape, but its long-term benefits and costs are still being evaluated.