A report by Ricardo-AEA estimates that around 12 000 wells would be needed if the UK were to theoretically develop its unconventional resources; including shale gas and coalbed methane (CBM). Of those 12 000 wells, roughly one third would be drilled to extract CBM.
The report, 'Unconventional gas in England: description of infrastructure and future scenarios', explained that, if patterns observed in North America and Canada are repeated, it is likely that the CBM industry may continue to emerge at a pilot level for a period of several years, while the technical and regulatory issues are addressed. Intensive development with increased production may then be expected to take place over a period of 3 – 10 years, followed by an extended period of more stable production. The permitting, infrastructure and local factors highlighted in relation to shale gas will also set similar constraints of the CBM industry in the UK.
Mark Broomfield, specialist consultant at Ricardo-AEA said that the consultancy estimates 1 – 10 billion m3/year of unconventional gas consumption in the UK by 2013, which is down on an Institute of Directors’ report from 2013 that estimated a mid-range forecast of 30 billion m3/year.
Broomfield said that the unconventional resource sector in the UK was “looking at a slow start but substantial investment over the coming years,” he said. “It does seem to me that a consensus is emerging of production of around 10-13 BCM in 15 years' time.”
Of the 12 000 wells needed to fully develop the unconventional resources found in the UK, Broomfield suggested achieving that figure would not be a realistic probability. “I don’t think [drilling 12 000 wells] is very likely,” he said. “More likely there will be between 600 – 3000 wells by 2035.”
The report estimated that for CBM, there would be between 200 – 1000 wells extracting the resource by 2035. “This seems a plausible figure, and Scotland are very much leading the way in developing CBM,” Broomfield told delegates at the Unconventional Gas Aberdeen 2014 conference.
In comparing the potential of the CBM industry in the UK to the US, the report noted that CBM production in the US totalled about 1.8 trillion ft3 in 2011 – roughly 6% of the total 28.5 trillion ft3 of natural gas from all US sources in 2011. The report also noted that CBM was considered an important ongoing supply of energy by the US Department of Energy.
UK CBM development
In 2010, the British Geological Survey (BGS) mapped the locations of CBM wells in the UK and areas that may be of interest for future development. It was estimated that the UK has total onshore CBM resources of 2900 billion m3.
For CBM, the report noted that several companies were at the pilot development stage, for example at sites in Cheshire and North Yorkshire, but also that large-scale production in the UK is unlikely before 2016.
The report suggested that looking at more advanced CBM projects in the UK, such as the one being developed by Dart Energy at Lethan Moss in Scotland, could be a useful case study to ascertain site preparation, completion, production and abandonment practices likely to occur if the UK CBM industry develops.
Ricardo-AEA, Broomfield said, did a risk assessment of environmental risks of individual well development. “The key for any individual well is groundwater contamination – that's the number one risk; surface water contamination is also important, but that's really more to do with housekeeping and there are some fairly standard measures involved in control and management of surface spillage,” he explained, adding that well integrity was crucial.
Because it was a relatively young industry, he noted that there was not much experience with the post abandonment phases of unconventional gas developments.
The report noted that because CBM wells generally produce more water than conventional gas wells, and also produce less gas than conventional wells, the cost to dispose of the production water is a significant expense compares to that of conventional development.
Written by Sam Dodson
Read the article online at: https://www.worldcoal.com/cbm/02052014/cbm_infrastructure_in_uk_must_be_developed_cbm23/