What potential reserves of shale gas are there in the UK?

14 August, 2014

(updated 7^th August 2014).

The amount of shale gas in the UK that could actually be recovered remains uncertain, given that relatively few detailed explorations have been conducted to date. The majority of predictions are based on the UK’s three main shale gas formations; the Bowland Shale in Northern England, the Weald Basin in Southern England, and the Midland Valley of Scotland.

Estimates of the UK shale gas ‘in place’ suggested that the amount of shale gas resources underground (regardless of the feasibility of extracting the gas) lay somewhere between 2.8 and 39.9 trillion cubic metres (tcm). The lower figure is based on analogies drawn with similar formations in the USA, and envisages 2.7 tcm in the Bowland shale (the largest resource) and less than 1 tcm in the Weald basin. The larger figure is based on 3D geological modelling by the British Geological Society, which estimates around 37.6 tcm in the Bowland Shale, 2.3 tcm in the Midland Valley, and no shale gas in the Weald Basin. Two drilling tests conducted by oil and gas company Cuadrilla in the Bowland area suggest the gas in place in that area could be around 5.7 tcm..

The British Geological Society did not assess how much of the gas in place could be feasibly extracted with existing technologies (known as ‘technically recoverable resources’). Cuadrilla has suggested that around 15-20 per cent of resources in the Bowland shale could be technically recoverable.

However, it is important to distinguish between the different types of estimates presented, as they suggest very different outcomes for shale gas in the UK. Resources or ‘gas in place’ typically refers to the volume of gas in the rock, but does not factor in a feasibility assessment of whether the gas can actually be extracted or not. ‘Technically recoverable resources’ are estimates of the volume of gas that could be extracted, given the current technologies available. But ultimately, what really matters is the volume of gas that can be technically recovered and also that it is also economically and legally viable – the so called ‘proven reserves’. Far fewer studies assess technically recoverable resources or proven reserves. Most of the information available focuses on gas in place estimates which do not account for the actual feasibility of extraction. Indeed, proven reserves have yet to be estimated for the UK.

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