The subject of the size of the amounts of UK shale gas been open to much speculation and misunderstanding right from the start. Key opponents such as Damian Carrington of the Guardian have derided Cuadrilla’s estimates from the very start and they have been consistent in insisting that we don’t even have any gas, so why bother looking and full speed ahead, although whether that would be under wind, nuclear or coal isn’t specified. The main thing is we don’t have any gas anyway. Andrew Rawnsley famously told us the weekend previous:
Then there is the huge hole at the heart of the frack-heads’ dream. No one even knows yet how much shale gas can be profitably extracted. Estimates of the exploitable reserves vary wildly.
The explanation is geology. Shales in Europe are generally thinner and deeper, and therefore much more expensive to tap, than those that have been successfully exploited in the United States. And Britain looks likely to be one of the less promising prospects in Europe because its shales are typically among the thinnest.
The Daily Telegraph yesterday asked the question how much gas do we actually have without getting even close to providing an answer.The discussion is complicated by basic misunderstandings of the reserve and resource figures.This definition is from the Society of Petroleum Engineers may help
Unlike the inventory of a manufacturing company, reserves are physically located in reservoirs deep underground and cannot be visually inspected or counted, but rather are estimates based on the evaluation of data that provides evidence of the amount of oil and gas present. There is no definitive answer until the end of a reservoir’s producing life. All reserve estimates involve some degree of uncertainty. The estimation of reserves volumes is generally performed by highly-skilled individuals who use their experience and professional judgment in the calculation of those volumes.
Reserves represent that part of resources which are commercially recoverable and have been justified for development.
Meanwhile, this is the introduction to a presentation DECC made at Prospex in London last week. It hasn’t yet been published on the DECC site, but is in the public domain and I’ve placed the full report in the NHA Library to your right.
Assessment of the shale gas resources of the Carboniferous basin shales of central Britain: preliminary report
The UK shale gas industry is in its infancy, and ahead of more drilling, fracture stimulation and testing there are no reliable indicators of potential productivity. In 2010 DECC estimated that, by a simple scaled basin-size analogy with similar producing shale gas plays in North America, the total UK shale gas recoverable reserve potential could be as large as 150 bcm (5.3 tcf, with 4.7 tcf of that in the Upper Bowland Shale of central Britain). Following on from that work DECC has commissioned the BGS to evaluate the gas in place resource potential for the entire Bowland shale, and work is underway to integrate over 15,000 miles of 2D seismic data with over 100 wells that penetrate the interval, Rock-Eval laboratory studies and basin modelling. By the end of 2012, a detailed technical report will be published on the DECC website with maps, well correlations and thermal maturity cross sections. This interim report provides a quick look at the mapping progress, An estimate of the potential resource size of the greater Bowland Shale gas play will be added in the final detailed technical report.
We’re running out of 2012. We may or may not see the technical report this month, but key point number one means I have to apologise to Andrew Rawnsley for saying the shale was six thousand feet thick:
In the Bowland Basin, the total Bowland-Hodder unit is interpreted to reach a thickness of up to 1900 m (6300 ft), but the interval may be much thicker within the narrow, fault-bounded Gainsborough, Edale and Widmerpool basins (Figs. 4 & 5; up to 3000 m / 10000 ft, 3500 m / 11500 ft, and 2900 m / 9500 ft respectively).
Where they have been buried to sufficient depth for the organic material to generate gas, the Bowland-Hodder unit basin shales have the potential to form a shale gas resource analogous to the producing shale gas provinces of North America.
The full scale of production activities which might eventually be proposed in the UK is unknown, but this preliminary work indicates that there is significant potential for shale gas and shale oil production.
The key word in the second sentence is of course ‘potential’. But since the financial risk lies entirely on private companies, what’s to lose by looking? As Francis Egan of Cuadrilla said last to the ECC committee, “We can’t talk the gas out of the ground.”
Many people will be scratching their heads over what much of the report means, but this report shows the Bowland Basin extending across northern England. The Cuadrilla discovery may yet prove to be only the tip of a shale iceberg, with other areas of equal, or even greater, importance.
This is only for Northern England. Southern England is also being studied, and many consider that area especially interesting for oil. Central Scotland and Northern Ireland don’t even get a look in yet, although geologically they are of great interest.
Oh, and before I forget from page 4.