There is considerable upside potential in the lower unit,
but the resource estimation for this unit has a much higher
uncertainty due to the paucity of well data so far and potentially less favorable lithologies. The estimated range of gas
in place for this thick unit is 650-1,065-1,834 tcf ( 18. 7-31.2-
51. 9 tcm). The estimated range of gas in place for this thick
unit is 658-1,065-1,834 tcf ( 18. 7-31. 2-51. 9 tcm). The total
range for estimated gas in place is 822-1,329-2,281 tcf ( 23.3-
37. 6-64. 6 tcm) for the combined upper and lower parts of
the Bowland-Hodder unit.
This large volume of gas has been identified in the shales
beneath central Britain, but not enough is yet known to estimate a recovery factor nor to estimate potential reserves.
An estimate was made in the previous DECC-commissioned
2010 BGS report that the Carboniferous Upper Bowland shale,
if equivalent to the Barnett shale of Texas, could potentially
yield up to 4. 7 tcf (133 bcm) of shale gas. In the absence of
subsurface volumes of potential gas-bearing shale, this early
estimate was based on the relative areal extent of the basins.
Now, after detaild subsurface analysis, a “bottom-up”
resource assessment of gas in place has been made, which
more accurately reflects the area’s shale gas potential. However, it is still too early to use a more refined methodology,
like the US Geological Survey’s technically recoverable resource “top-down” estimates which require production data
In time, the drilling and testing of new wells will give
an understanding of achievable, sustained production rates.
These, combined with other nongeological factors such as
gas price, operating costs, and the scale of development
agreed by the local planning system, will allow estimates of
the UK’s shale gas reserves to be made.
Other areas in the UK have shale gas and shale oil potential, and later in 2013 the Jurassic shales in the Weald basin
of southern England will be the subject of a further BGS/