One of the most topical issues in geology at the moment is hydraulic fracturing of shale to extract hydrocarbons that are trapped in the sediment. Shale is largely impermeable so gas and oil that has matured from organic material within the shale cannot migrate (flow) into a rock from where the gas and oil can be pumped. The technique is used already to increase the recovery of oil from North Sea oil fields and also to make geothermal energy schemes work.
To make the rocks more permeable water is pumped into the shale at high pressure to break the rock to create pathways for oil and gas to flow out of the rock. Ceramic beads or sand is pumped with the water to stop the fractures closing as illustrated here. The water can lubricate pre-exisiting faults and cause earthquakes (though these might better be described as minor tremors).
The issue inspires passionate debate on both sides of the argument. Organisations such as Greenpeace are concerned about both the direct and indirect environmental consequences of extracting hydrocarbons in this way. The Government have endorsed the technique as a way of increasing our energy supply, thus decreasing the cost of energy and also to boost our energy security - we are currently dependent on buying gas from Qatar to keep our houses warm.
To see the science behind fracking, have a look at the British Geological Survey's You Tube channel.
The UK is not the only country to be trying to decide about the economic and environmental viability of fracking.
Do you think that we should frack for the gas that we need?
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