Showing posts with label BGS. Show all posts
Showing posts with label BGS. Show all posts

Tuesday, 27 August 2013

Onshore mineral resource maps


Onshore mineral resource maps

This site is a really useful resource,showing all the data on the ‘county maps’ merged to produce an online Minerals Information GIS for each English region



The British Geological Survey was commissioned by the Office of the Deputy Prime Minister (now DCLG), through the research project Mineral Resource information in Support of National, Regional and Local Planning, to prepare a series of ‘county’ mineral resource maps. This work was completed in early 2006 and a series of digitally generated maps at a scale of 1:100 000 are available. These maps cover 44 administrative areas or groups of administrative areas, giving information for the whole of England and parts of South Wales.
Four major elements of information are presented on the summary maps:
  • the geological distribution of all onshore mineral resources the location of mineral extraction sites
  • the extent of mineral planning permissions and licences for coal extraction
  • the extent of selected landscape and nature–conservation designations (National Parks, AONBs, SSSIs, NNRs and scheduled monuments).

This is an extract from the ( much larger) map for Herefordshire and Worcestershire, showing oil wells and coalfields.


Saturday, 24 August 2013

How did we get to be of interest? Surely there is no shale gas here in Herefordshire?

How did we get to be of interest? Surely there is no shale gas here in Herefordshire?

Well, actually, there might be.

In the course of my studies into this I came across an interesting research paper, whose data was used in the DECC report - with more information about potential sites and more.

 The British Geological Survey (BGS) carried out a basic geological study of shale gas basins  through the use of conventional oil and gas well data to identify potential targets.

This report is basically  looking at lots of geological information to find a UK version (analogue) of the US shale gas rich Barnett Shale region. It is packed full of information and, if you look, the map on page 19 identifies Fownhope and Fowlet Farm (near Eastnor) as Cambrian Shales wells. This map also shows the main areas where hydrocarbon source rocks can be found in the UK.



Main hydrocarbon source rocks (outcrops). Wells reaching Tremadoc to Cambrian in England and hydrocarbon
 wells in northern Ireland which tested a tight gas Carboniferous play in several phases (Griffith 1983) as recently as 2001
 
The report states that
  
Satellite basins of the Worcester Graben  beneath the Bristol Coalfield and in Berkshire to the east (Mississippian strata are feebly developed in the latter area) provide the closest UK tectonic analogues to the Fort Worth Basin.

The report also specifically mentions Fowlet Farm and Fownhope boreholes SW of the Malverns as having proven Upper Cambrian black shales. The report details how, in these boreholes
 ~68 m of black shale has been intruded by dolerite sills; the shales have high gamma ray values and represent a potential source rock. Outcrop measurements of TOC support this interpretation, with values of ~5% recorded by Parnell (1983)

Obviously there is a world of difference between "potential source rock" and an actual drilling site, but the report does show why E. Herefordshire has become of interest and maybe why it was included in the recent DECC report on Unconventional Hydrocarbon resources


Still can't find any mention of Much Marcle, though!







If you are interested, the abstract for the report says
Organic rich shale contains significant amounts of gas held within fractures and micro pores and adsorbed onto organic matter. In the US shale gas extracted from regionally extensive units such as theBarnett Shale currently accounts for ~6% of gas production. Shale gas prospectivity is controlled by the amount and type of organic matter held in the shale, thermal maturity, burial history, microporosity and fracture spacing and orientation. 
The main UK organic rich shale sequences have been mapped at the surface and in the subsurface using a combination of outcrop, well and seismic data. Potential targets range in age from Cambrian to the late Jurassic: younger shales have been excluded because they have not reached the gas window, but they may possess a biogenic gas play. A GIS showing the distribution of potential reservoir units has been combined with information on hydrocarbon shows, thermal maturity, fracture orientation, gas composition and isotope data to identify potentially prospective areas for shale gas in the UK. These include Lower Palaeozoic shale basins on the Midland Microcraton, Mississippian shales in the Pennine Basin and Pennsylvanian shales in the Stainmore and Northumberland basin system

Friday, 23 August 2013

So who mentioned Herefordshire? And why?



 A report produced by the British Geological Survey (BGS) for the Department of Energy and Climate Change (DECC) seems to have been the catalyst for the media reports about possible Fracking in  Herefordshire.


This report came out recently and is based on recent analysis, together with published data and interpretations. The front page carries a striking "weathermap" style map showing





Further on in the DECC report is a map showing the existing areas of  Petroleum Exploration and Development Licences, conventional Oil and Gas Fields, locations of conventional wells drilled
 and with the areas under consultation which may be offered in the upcoming 14th onshore Oil and Gas Licensing Round highlighted in pink

As you can see, that includes areas of Herefordshire.
 
Fig.2 Current UK Petroleum Exploration and Development Licences, conventional Oil and Gas Fields, locations of conventional well drilled, and the areas under consultation currently which may be offered in the 14 th onshore Oil and Gas Licensing Round.



But why the specific references of Fownhope and Eastnor in the media? Well, looking at Fig 4 in the report we can see the reason why E Herefordshire has been in the news - we get a mention.



Fig.4 Principal UK onshore hydrocarbon provinces 
While discussing Fig 4, the report talks about the  3 main age-constrained UK shale groupings that are of interest, and goes on to identify them.  The third shale grouping of interest is identified as the riskier UK play and is the Upper Cambrian shales thought to occur widely in the subsurface between the Caledonides and Variscan fold belts on the Midland Microcraton.The report then mentions that conventional UK hydrocarbon exploration wells on this play include wells at Cooles Farm, Collington, Usk and Fownhope.

So now we know why Fownhope is mentioned. (Collington is near Edwyn Ralph but does not get any further mention by the media.)
 
But why Eastnor? 

Well, because the DECC report refers to existing boreholes with Cambrian/Tremadoc strata at Fownhope and Fowlet Farm  (near Eastnor)


Fig. 10 Cambrian and Tremadoc outcrop. Many very small outcrops are not shown.

 

 So now we know why Eastnor was mentioned.



So in conclusion, a report issued by the Dept of Energy and Climate Change and produced by the British Geological Survey, mentions E Herfordshire sites at Fownhope and Eastnor in the context of Unconventional Hydrocarbon Resources and talks about our area as being a "riskier play" but still thinks it worth including.


And that's why, suddenly, E. Herefordshire is in the media as a possible site for Fracking .

Can't find any mention of Much Marcle, though!



(All the images on this page are taken from the BGS/DECC report and are copyright DECC 2012)


Wednesday, 21 August 2013