This paper reviews the results of the DECC-commissioned 2012-13 BGS study to estimate the shale gas resource assessment of the Carboniferous Bowland Shale in central Great Britain. Over 15,000 miles of seismic data were interpreted and integrated with well and outcrop control, BGS mapping, 3D depth modelling, geochemical analysis, and 2D thermal maturity basin modelling. The Bowland Shale, and its laterally equivalent basinal shale formations are known to be important source rocks. The study recognised two depositional units; an organic-rich upper part that is a widespread marine shale unit drowning most platform highs and a lower unit comprised of very thick rift-basin fill shales with mass-flow carbonates and rare mass-flow sandstones, passing laterally to platform carbonates on the paleo-highs. An interpreted top gas window thermal maturity surface was integrated with the depth structure mapping to identify the volume of Bowland shale in the gas window which was used as one of the input parameters for a Monte Carlo simulation of the in-place gas resources. The study estimates a large volume of gas in the shales beneath the UK, but concludes that not enough is known yet to estimate a recovery factor, nor to estimate potential reserves
