A consistent stratigraphic study of the western European Carboniferous Basin has allowed the generation of eight palaeogeographic timeslices. These illustrate a model of large scale eastern (dextral) tectonic escape on the northern side of a convergent margin and integrate the diverse tectonic and sedimentary settings observed within the basin as a whole. This model can be compared to the present day eastern Mediterranean, where a similar range of diverse tectonic settings are observed. Reservoir and source distribution is discussed for each time-slice along with the present distribution of Carboniferous oil and gas fields. Due to the diversity observed no unique play type can be distilled from the data to explain the distribution of hydrocarbons within the studied area.

Three Jurassic unconformities of intra-Aalenian, intra-Callovian and intra-middle Oxfordian age are consistently identified within the literature for the North Sea region but despite their common recognition these unconformities remain poorly understood and they are essentially spatially and temporally unconstrained. The recent development of a sequence stratigraphic framework for the Jurassic of the North Sea allows for a thorough investigation of the spatial and temporal characteristics of the intra-Callovian and intra-Oxfordian unconformities and these data have important implications for Middle and Late Jurassic rifting within the North Sea region.The intra-Aalenian unconformity is believed to have been generated as a result of an increase in geothermal gradient within the area and subsequent thermal uplift that preceded rifting. The stratigraphic gap associated with this unconformity increases towards the proposed location of a Middle Jurassic, triple junction centred dome. In contrast the stratigraphic break associated with the intra-Callovian and the intramiddle Oxfordian unconformities is found to increase onto what are now intra-rift highs and rift margin areas. These unconformities occur at the same time as distinct changes in the geometry of the fill of the triple junction and also occur at the same time as seismic scale extension. They do not appear to correlate to any supposed global fall in relative sea-level. Stratigraphic data indicate that three phases of extension occurred during the Callovian, middle and late Oxfordian and lastly during the Kimmeridgian and Volgian. Although the intra-Callovian and intra-middle Oxfordian unconformities can be confused with the effects of the Middle Jurassic North Sea dome unconformity, they are in fact the result of extension during the initial Callovian and Middle/late Oxfordian rift phases. The recognition of these regional unconformities suggests that the Middle and Late Jurassic rifting process was punctuated rather than being continuous.

Sequence stratigraphic analysis of North Sea Eocene and Paleocene seismic-reflection profiles and well data provides examples of lowstand, transgressive and highstand systems tracts, including the 'basin-floor thick', 'slope thick' and prograding-wedge facies of the lowstand systems tract. This study was initiated to evaluate the interpretation methodology, refine the biostratigraphic control and test the Vail-Exxon depositional model prior to undertaking a more regional study. The primary data consisted of 4200 km of multifold seismic reflection profiles distributed in a 20 km grid, calibrated using log suites from 45 wells including 37 with biostratigraphic data. Thirty-two micropalaeontologic bioevents from top Cretaceous to top Eocene were evaluated. Twenty-three bioevents were identified as useful chronostratigraphic markers and were used to constrain both well-log and seismic reflection profile correlations. In general, the mapped systems tracts are more spatially separated than suggested by the diagrammatic Vail-Exxon model and require biostratigraphic correlation to confirm temporal relationships. Many of the lowstand systems tracts appear to be line-sourced by several sediment-supply systems. Ten Paleocene and Eocene sequences were recognized in this study, compared to 22 on the Cenozoic cycle chart. The remaining 12 Cenozoic sequences are either absent or are coalescent and below the resolution of this study.

Critical to the successful exploitation of the northern margin of the Southern Gas Basin is the development of the Lower Carboniferous (Dinantian, Viséan) play. Whilst the exploration for intra-Carboniferous traps has been unsuccessful, the presence of large Base Permian evaporite sealed closures still holds opportunities. The discovery of hydrocarbons within one of these closures on the edge of the traditional gas basin suggests that migration of gas from Westphalian and Namurian coals and shales has occurred. Thus in this area, the primary remaining risk is the presence and distribution of reservoir. Two potential reservoirs are examined in the subsurface, the Fell Sandstone Formation and the Whitby Member. Onshore analogue data has been combined with the sparse offshore data to explore the distribution of these sandstones. The Fell Sandstone Formation was deposited at a time of high sediment supply resulting in a thick (300 m) succession of fluvial sandstones whose distribution is closely linked to the accommodation space developed in the hanging walls of contemporaneous faults. The Whitby Member (thickness 30 m) was deposited at a time of lower sediment supply which enabled relative sea-level changes to control the vertical distribution of sandstone bodies. It demonstrates some of the features which suggest it could infill a palaeovalley. If active faulting continued throughout this time then a similar hanging wall concentration of sandbodies, as is seen in the Fell Sandstone Formation, could be expected.

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