Unlocking the Resource Potential of the Bowland Basin, NW England

Abstract

Abstract The Bowland Basin of NW England is a key part of the Pennine Carboniferous Petroleum System which is estimated by the British Geological Survey to hold over 1300 TCF of total original gas in place (TOGIP) of shale gas resource. The basin is a Lower Carboniferous (Dinantian) extensional basin which underwent at least two major phases of rifting and intrabasinal tectonics. The basin was inverted in late Carboniferous times and subsequent burial continued until mid or late Cretaceous time. The gas-bearing shale section is extremly thick (>6000 ft) intensly naturally fractured and relatively complex structurally. Ongoing geoscience studies are focussed on addressing the the intrabasinal sedimentary architecture of the Bowland Basin, structural configuration, reservoir properties and the current stress regime. The Preese Hall-1 shale gas discovery well provides an opportunity to assess the shale gas characteritics of the Bowland Basin and its resource potential. Based on extensive core and log data the shale gas resource is estimated to be approximately 1 TCF per square mile (29 BCM per square kilometre). The gas is methane rich with little carbon dioxide and the less thermally mature parts of the succession includes significant wet gases. The gas density (gas per unit volume) in the Bowland Basin compares favourably with producing shales in North America, however, the gas saturated succession is significantly thicker. In this preliminary contribution we describe some of the basic properties of the basin including the stratigraphy and structure, rock properties and structural configuration along with our approach to the modelling the petroleum system and estimation of TOGIP. The gas resources of the Bowland Basin alone could make a significant contribution to UK energy supplies. Unlocking this resource potential requires understanding of the complex set of geological variables and devising a development strategy compatible with the social issues surrounding shale gas development.