Shale and hearty

The British Geological Survey has just produced a report on Scotland's shale resources, similar to the headline grabbing one it did last year for the Bowland. As previously, this is an estimate of the oil and gas in the ground rather than an estimate of what can be economically extracted.

This study offers a range of total in-place oil resource estimates for the Carboniferous shale of the Midland Valley of Scotland of 3.2-6.0-11.2 billion bbl (421-793-1497 million tonnes) (Table 1). Total in-place gas resource estimates are 49.4–80.3–134.6 tcf (1.40–2.27–3.81 tcm). The West Lothian Oil-Shale unit makes the largest contribution to this estimated resource.

For references, UK gas demand is just below the 3 tcf level. So if we can get 10% of the gas in place out, that's 3 years of UK demand or perhaps 30 years (?) of Scottish demand. Not to be sneezed at.

Comments

[Capell]

'But it's oor gas Jimmy!'.

[Rick Bradford]

**Not to be sneezed at.**

It will, however, be sneered at by the self-appointed Lofty Green Spokesmen.........

[Jimmy Haigh]

The West Lothian Oil Shale, of course, was where it all started with James (Jimmy perhaps...) "Paraffin" Young back in the latter part of the 18th Century.

[Doug Proctor]

You wouldn't think so, but 10% recovery is a high recovery factor for a difficult gas resource. The coal-bed methane resource is huge, but the recovery factor is very low, 9% in the American, extensional basins ONLY when you consider the core areas. In Alberta, it is <<1%, even if a few years ago there were government reports of massive amounts of gas-in-place (which was a true mathematically correct thing).

Try a percent or two. The fact there is not a conventional portion is very telling: geology has crap rock in association with good (porous, permeable) rock. If you can't map out a portion that already is productive as a window into what is not productive, you are dealing with very much a theoretical proposition.

Also not that Britain is in a compressive system. That means that fractures are closed, the true pipelines for production. Despite what you might hear from marketing salesmen, you cannot create an effective drainage system through fracking, only connect to one. The mathematics are quite simple: after the induced fracture volume is drained, you are restricted to the bakground (matrix) permeability. All horizontal drilling displays the same problem of non-scaling-up you might think you get in a frack: the surface area open to theoretical production does not give you a proportionality of production rate or reservoir reach. You have to be in contact with a general, widespread permeability. Horizontal wells and fracking are techniques to find those permeable zones that are not penetrated by a simple, 6" vertical wellbore.

There is a very good reason Gas-in-Place is mentioned, not Recoverable Gas-in-Place. GIP is a simple calculation based on gas released by crushing a given volume of rock to powder, multiplied by the volume of rock assumed to have that amount of gas. Reverable reserves require examples of recovery, even if the rock involved is not quite the same. Britain has verry little of that comparison. Which is a worrying situation for long-term development. In the States and in Canada we have always known of conventional (even if poor) production from the shale zones. We didn't have to prove productive capability, we had to extend the producive capability AND do it at a rate that paid for the effort within a reasonable period of time. Plus we already had the infrastructure in place and paid for.

Be aware of what you hear and are asked to both pay for and expect to save your butt.

[Pharos]

Jimmy Haigh

Thanks for that. Looked him up - clever man. I particularly liked this old photo

http://www.scottishshale.co.uk/KnowledgePages/Histories/index.html

[hunter]

Doug,
Too bad your sort of keen wit and sharp eyed look isn't performed on wind mill power.

[Vangel]

For references, UK gas demand is just below the 3 tcf level. So if we can get 10% of the gas in place out, that's 3 years of UK demand or perhaps 30 years (?) of Scottish demand. Not to be sneezed at.

First of all, as was pointed out in the initial posting, resource estimates are not proven reserves. Second, it is hard for me to see how it is possible to extract 10% of the gas out of a typical shale formation where porosity and permeability are serious problems. Third, if the return is low the output will have to be offset by the energy input that is necessary for extraction. Given the history of shale, horizontal drilling, and fracking you are not looking much to sneeze at.