A UK government policy report on shale, made in October 2012, notes that the government believes this form of energy extraction has the possibility of furnishing Scotland and the rest of the UK with stronger energy security, financial growth and employment; and that they are ascertaining its potential by supporting environmentally secure and safe exploration. The report also stated that the UK aims to continue improving their robust regulatory practice of exploratory endeavours, and boasts more than 50 years of national oil industry regulation (gov.uk. Policies).
In a 2014 report by the RT Hon Michael Fallon MP, and the Department of Energy and Climate Change, on the estimates of shale gas and oil in Scotland; it was stated that with regard to the report of British geological surveys in connection to the Midland Valley, Scotland resources, it is apparent that there is only a modest quantity of oil in place, and that a figure of 6 billion oil barrels is viewed as the central estimate. There is however, great uncertainty, due to the fact that compared to other regions of study, there is less seismic data and historic wells are fewer. Exploratory testing and drilling is of crucial value in determining the amount of oil that can be recovered due to the area’s historic mine workings and intricate geology. The British Geological Survey’s Director of Science and Technology, Professor Mike Stephenson, stated that prior to drilling and testing, it is not feasible to calculate the oil reserves, and remarked on the comparative absence of data in relation to the former Weald Basin and Bowland-Hodder DECC-BGS studies (gov.uk. Estimates of Shale Gas and Oil in Scotland).
Hydraulic fracturing, which is also simply referred to as fracking, is a cutting-edge form of drilling which has been employed commercially for over 60 years on over 2.5 million wells around the world. The procedure utilises high pressure equipment to inject water into formations of shale rock in order to extract oil and gas (gov.uk., Policies.,What is Fracking).
The Hydraulic fracturing process requires straight drilling which can go as deep as a mile or more below the earth’s surface, after which the drilling slowly turns horizontal for a further several thousand feet, thereby allowing one single surface to have the capacity for a collection of wells. After the well has been drilled, and is cemented and cased, the well pipe’s horizontal portion is punctured with small perforations so that a standard mixture of sand (9.5%), and water (90%), generate micro-fractures within the rocks after these elements are pumped in at extreme pressure. This results in rock micro-fractures which the sand grains are able to keep open. In order to decrease friction and thus lower the magnitude of diesel-powered aspects of pumping, which stops pipe corrosion and lowers air emissions, a number of chemical additives are used. This facilitates better efficiency, and is less damaging to the environment (gov.uk., Policies.,What is Fracking).
Shales can be described as sedimentary rocks which are finely grained, and made up from less than 1/16 mm of clay and silt mineral particles. Characteristically, these particles amass along the bottommost areas of huge bodies of water. Over time, algae, plankton, and other marine organisms die, and in conjunction with inorganic muds and silts as the sediment accumulates, generate the organic content which is crucial for the production of hydrocarbons. The shale’s maturity, which is ascertained by the period of burial time, the exposure temperature, and the burial depth, is another equally important component. The process involves heating the shales to attain a precise pressure and temperature. The first commodity to be produced at lower pressures and temperatures which run at approximately 110°C at a depth of 4-5 kilometres, is shale oil.
Currently, the oil shale formation at West Lothian Firth of Forth, is situated below sea level at an approximate maximal of 3,500 feet, and extend to an approximate maximal thickness of 1.1kiolmeter. In order for shale to attain the same strength as an unconventional reservoir, when hydraulic pressure is applied to crack open the shale and deform it in a brittle fashion, the correct physical properties are mandatory. If this is not the case, once the hydraulic pressure is applied and the shale is opened up, the shale acts plastically, and in order to stop flow, re-seals the cracks. In the case of the latter, a number of Midland Valley samples tests have indicated that the shales may act in a more plastic way due to their being more carbonate poor and clay-mineral rich, compared to the UK’s other source rocks which are used for unconventional drilling (Britgeopeople).
In summary, whilst Scotland boasts substantial reserves of oil shale, the process of fracking is extremely complex, and a substantial amount of exploratory work has to be undertaken to ensure that the type of rock is suitable, and the process would be worthwhile.
- Britgeopeople. Online: http://britgeopeople.blogspot.co.uk/2015/02/filming-for-bbc-scotland-documentary-on.html (Accessed 26 March 2015).
- Gov.uk. Online: Estimates of Shale Gas and Oil in Scotland
https://www.gov.uk/government/news/estimates-of-shale-gas-and-oil-in-scotland-published (Accessed 26 March 2015).
- Gov.uk Policies. Online: https://www.gov.uk/government/policies/providing-regulation-and-licensing-of-energy-industries-and-infrastructure/supporting-pages/developing-shale-gas-and-oil-in-the-uk 26 February 2015 (Accessed 26 March 2015).
- What is Fracking. Online: http://www.what-is-fracking.com/what-is-hydraulic-fracturing/ (Accessed 26 March 2015).