The Southern Gas Basin of the UK North Sea has been an active theatre of exploration and production for over 40 years. During this time hundreds of wells have been drilled and three major prospective gas play systems Bunter, Rotliegendes and Carboniferous, identified. The major recent geophysical tool has been 3D pre stack anisotropic depth migration which has been successful in revealing depth structure traps beneath the distorting lens of the Chalk and Zechstein salts. Current challenges include high grading combination stratigraphic exploration traps within the Rotliegendes and Carboniferous, and optimising / assessing production or storage opportunities within producing or abandoned fields. This paper gives three examples where the targeted use of rock physics analysis combined with geological and geophysical modelling have identified or rejuvenated new opportunities within previously well explored areas in the Rotliegendes and helped unlock new potential in the Carboniferous and Bunter. Historically, rock physics and AVO style methods have not been widely used in the SGB, apart from in the Triassic Bunter sandstone reservoirs mainly because the prior emphasis has been on structural traps and because the depth and low porosity nature of some of the major reservoirs . However there have been other more complex reasons, including the difficulty of applying analytical methods and seismic data suitability the paper discusses the reasons for this and how availability of new seismic data types and analysis methods have changed to allow more sophisticated model and data driven methods. The three examples span about 80million years in reservoir age from Late Carboniferous to Triassic and a variety of geological facies at depths from 13,000ft in the Upper Carboniferous to 6,000 in the Triassic. The Triassic aged reservoir of the Forbes gas field in Block 43/8 was abandoned by BHP in 1992, the paper shows how the use of rock property based predictive seismic modelling combined with a calibrated density inversion using the Aki and Richards 3 term equation has defined remaining high saturation gas potential in the ～20% porosity Bunter reservoir at about 5700 ft that may form the basis of a field reactivation or gas storage project. The Permian aged Leman sandstone around the Davy, Inde and Leman gas fields has been analysed. Well and seismic data quality is good and although lithologic effects dominate the rock physics trends porosities are around 15% at 7500ft, characterization and modelling of subtle but potentially useful variations in poisons ratio have been modelled that relate to the presence of gas in and around the existing fields. The late Carboniferous Barren red measures sequence around the Schooner field has been analysed to target higher net to gross sands in this complex sedimentological unit. The units are at around 12-13,000 ft depth and are highly compacted and rigid, and show porosities between 9% and 15%. Whilst the sands and shale's show similar properties, their seismic character displays variation with seismic offset angle such that Lame's parameters can be used as a basis for discriminating sand from shale.
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