BGS has this week released new web pages and videos which include an abundance of information on shale gas.
Shale gas is considered to be a potentially important resource that is tightly bound in sediments which geologists call “black shale”. The shale of interest to gas producers was formed hundreds of million years ago in marine basins that were filled with sand and silt and organic-rich material deposited in the marine environment or transported from the adjacent landmass. These basins were deformed through tectonic compression and the gas is preserved in rocks buried 2km or more deep, where the gas has not yet escaped.
Currently gas consumed in the UK comes from conventional resources that are concentrated and trapped after gas has moved out of its source rock, for example in the North Sea gas fields. Black shale is essentially a source rock in which the gas is tightly bound to silt and sand grains and needs to be pushed out by injection in a process that is called fracking. There are large shale gas resources in the UK and elsewhere in Europe, in particular in Poland, the Ukraine and Baltic states. The potential of the shale gas resource has been known for some time and has been exploited in the USA, where some estimates indicate a potential reserve that would satisfy the US gas supply for hundreds of years. The recent interest in exploiting shale gas in Europe is due to increased gas prices and concerns over ensuring a secure supply of gas, but it is also due to improvements in drilling technology which allow efficient and safe extraction of gas if regulated properly.
National energy security must be considered and the economics of importing gas over exploitation of national resources must be assessed. Furthermore gas has advantages over coal in producing energy in power stations, as during the burning process it emits about 50% less carbon dioxide. In both cases however, the CO2 should be captured and stored underground (see the BGS website on carbon capture and storage); capturing and burying the CO2 will be required by international regulation in the future in order to control CO2 emissions into the atmosphere.
The newly released shale gas information on the BGS web site is, by necessity, quite technical in places, but is still a very useful source of information for the less technically minded and for those who want to understand its potential as an energy resource of the future. BGS, like government, must tread a delicate line between encouraging industrial exploitation of resources through full and open exchange of our data on resources and reserves, both in the UK and world-wide, and ensuring that we maintain an assessment of the security of supply of a number of key resources, whilst ensuring environmentally acceptable resource exploitation. An important aspect of this is establishing environmental baselines for groundwater, such as for methane in groundwater and the state of local ecosystems.
If you would like to know more, there is a lot of important information on the website, but please feel free to contact the BGS scientists who are experts in various aspects of shale gas resources, reserves and their potential exploitation.