Wednesday 21 August 2019

Fracking: UK shale gas reserves ‘significantly lower than previous estimates’

The capacity of shale gas reserves in the UK could be “significantly lower” than estimates previously set out in 2013.

That’s according to the University of Nottingham and the British Geological Survey (BGS), which claim the figures that were projected six years ago were based on a “desk top study”, using data from US shale and estimating the shale gas resources “as opposed to the actual reserve”.

The previous estimates suggest that UK shale gas, extracted through a process called fracking, could potentially provide up to 50 years’ worth of current gas demand, however, the latest research has found it could correspond to less than 10 years of supply at current demand.

The BGS and the university’s Faculty of Engineering say their estimates are derived from actual UK shales, using gas generation absorption data, “further supported by field data”.

According to their new study, the amount of gas in place - assuming an economic recovery rate of 10% - would be a maximum of 20 trillion cubic feet. That would be equivalent to around seven years' worth of gas at current UK rates of consumption.

The research suggests the data will be of value to companies in helping them optimise their shale gas extraction technology and exploration.

Dr Christopher Vane, BGS Head of Organic Geochemistry said: “This cutting edge science shows that shales within the Bowland Formation could potentially contain less recoverable gas than previously thought, confirming that the UK’s geology needs to be carefully managed and demonstrating the strategic value of UK core and accompanying organic geochemical information.”

Shale gas reserves are also expected to vary across sedimentary basins, depending on rock composition, organic carbon contents and fracture and faulting patterns.

Professor Colin Snape, Director of the Centre of Doctoral Training in Carbon Capture and Storage and Cleaner Fossil Energy, added the laboratory test procedure will help improve people’s understanding and the government’s decisions around the future of what role shale gas can play in meeting the UK’s energy demand.

Response

UK Onshore Oil and Gas (UKOOG) said the only way to really know the extent of a shale resource is by drilling, fracking and flow testing.

Chief Executive Ken Cronin added: “Nottingham in their research have analysed a limited amount of core from one Bowland shale well drilled in 2011, which was subsequently decommissioned without hydraulic fracturing or flow testing. There was no calibration with the US or any interaction with the company that drilled the well.

“The industry is currently in the process of exploration in various parts of the Bowland Shale to test the geology and whether the gas will flow commercially. This involves 3D seismic surveying, core drilling, hydraulic fracturing and flow testing. To date we have made significant advancements in the understanding of the resource potential contained within UK shale, with very encouraging results seen at both Springs Road and Preston New Road which have demonstrated properties in line with world class, US shale plays.

“What we know now is that we have a world class resource which has broadly supported the estimates originally published by the British Geological Survey. Indeed, in terms of potential gas flow indications, the results are at the upper end of our original forecasts. Neither do we agree with the generalisations and assumptions used by the authors of this research regarding the uniformity, nature and quality of the rocks and reservoirs. One of the largest lessons learned from the USA’s shale revolution is that shales are not homogenous and that well location, even within a single basin, can be paramount to the success of the well. It appears that no basin variation factors have been significantly considered in this generalised study.

“All research is useful, but it needs to be understood in context. We remember the comment made many years ago by a senior geologist in the North Sea, who was so convinced that there wasn’t any oil to be found that he promised to drink any that was discovered. Since then, the North Sea has produced over 40 billion barrels of oil equivalent."