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Unlock This CourseShale gas and oil are types of unconventional fossil fuels that have revolutionised energy production in recent years. Unlike traditional oil and gas found in large underground reservoirs, shale hydrocarbons are trapped within layers of fine-grained sedimentary rock called shale. This energy source has become increasingly important for energy security, particularly in countries like the USA.
Key Definitions:
Shale gas and oil formed millions of years ago when organic matter was buried under layers of sediment. Unlike conventional reserves, these hydrocarbons remain trapped in the source rock rather than migrating to reservoir rocks. The tight nature of shale means special extraction methods are needed.
Hydraulic fracturing, commonly known as fracking, is the key technology that makes shale energy extraction possible. This process involves several stages and requires significant water resources and specialised equipment.
The fracking process begins with drilling a vertical well down to the shale formation, typically 1-3 kilometres deep. The well is then turned horizontally to access more of the shale layer. A mixture of water (90%), sand (9%) and chemicals (1%) is pumped at extremely high pressure into the rock, creating fractures that allow oil and gas to flow to the surface.
Each fracking operation uses 15-20 million litres of water. This creates competition with other water users and raises concerns about water scarcity in some regions.
Chemicals help reduce friction, prevent corrosion and kill bacteria. Though only 1% of the mixture, this still represents thousands of litres of chemicals per well.
Sand keeps the fractures open after pressure is released, allowing continued flow of oil and gas. Millions of tonnes of sand are used annually in fracking operations.
Shale energy extraction raises significant environmental concerns that affect local communities and ecosystems. These impacts have led to public opposition and regulatory challenges in many countries.
Fracking can potentially contaminate groundwater through chemical spills, faulty well casings, or migration of fracking fluids. Wastewater from fracking operations contains high levels of salt, chemicals and sometimes radioactive materials that must be safely disposed of.
Injection of wastewater into deep disposal wells has been linked to increased earthquake activity in some regions. Oklahoma experienced a dramatic increase in earthquakes after large-scale fracking began, with over 900 earthquakes of magnitude 3.0 or higher recorded in 2015 alone.
Fracking operations release methane, a potent greenhouse gas and other air pollutants. Communities near fracking sites report increased rates of respiratory problems and other health issues. Volatile organic compounds (VOCs) released during extraction can contribute to ground-level ozone formation.
Despite environmental concerns, shale energy development offers significant economic advantages, including job creation, reduced energy imports and increased government revenues through taxes and royalties.
The shale industry supports millions of jobs directly and indirectly. In the USA, the sector employs over 2 million people in drilling, transportation and supporting industries.
Domestic shale production reduces reliance on energy imports, improving energy security and reducing trade deficits. The USA became a net oil exporter in 2019 largely due to shale production.
Shale development brings investment to rural areas, providing landowners with lease payments and royalties whilst supporting local businesses and services.
The USA has experienced a dramatic transformation in energy production since 2008. The Permian Basin in Texas and New Mexico has become the world's most productive shale oil region, producing over 4 million barrels per day. This boom has made the USA the world's largest oil producer, overtaking Saudi Arabia and Russia. However, it has also led to environmental controversies, particularly in Pennsylvania's Marcellus Shale region, where communities have reported water contamination and health problems.
The UK has significant shale gas reserves, particularly in the Bowland Shale formation beneath northern England. The British Geological Survey estimates these reserves could supply the UK's gas needs for decades. However, development has been limited due to strict regulations, public opposition and geological challenges.
Cuadrilla Resources attempted to develop shale gas sites in Lancashire but faced significant challenges. Operations at Preston New Road were suspended in 2019 after causing earthquakes exceeding regulatory limits. The UK government imposed a moratorium on fracking in 2019, citing scientific uncertainties about seismic risks. This demonstrates how geological conditions and regulatory frameworks can limit shale development even where resources exist.
Shale energy resources are found worldwide, but their development varies significantly between countries due to geological, technological and political factors.
The largest technically recoverable shale gas reserves are found in China, Argentina, Algeria and the USA. However, the USA remains the only country to successfully develop shale resources at scale, producing over 60% of its natural gas from shale formations.
The future of shale energy depends on technological advances, environmental regulations and competition from renewable energy sources. Climate change policies may limit long-term development as countries transition to cleaner energy systems.
Advances in drilling technology, data analytics and environmental management continue to improve the efficiency and reduce the environmental impact of shale operations. Enhanced recovery techniques and better waste management systems are being developed to address current challenges.
New drilling techniques and digital technologies are reducing costs and environmental impacts whilst increasing recovery rates from existing wells.
Falling costs of renewable energy and battery storage present increasing competition to shale gas, particularly for electricity generation.
Government commitments to net-zero emissions may limit future shale development as countries prioritise renewable energy sources.
Shale energy has fundamentally altered global energy markets and geopolitics. Countries with large shale reserves have gained energy independence and reduced their vulnerability to supply disruptions. However, the boom-bust cycles typical of shale production create price volatility that affects global energy markets. The rapid decline rates of shale wells mean continuous drilling is required to maintain production levels, creating ongoing environmental and economic challenges.