ALBERT

Description: Extract The early discovery of the Arbroath Field in 1969, and the Montrose and giant Forties fields in 1970, initiated intensive exploration of the Tertiary deep-marine play in the North Sea region. Numerous subsequent discoveries (Fig. 1), including Frigg (in 1971), Maureen (in 1973), Gannet (in 1973), Andrew (in 1974), Pierce (in 1976), Everest (in 1982), Alba (in 1984), Gryphon (in 1987), Nelson (in 1988), Harding (in 1988), Jotun (in 1994), Siri (in 1995) and Merganser (in 1995), demonstrate the success of this play and the geological diversity of Paleocene and Eocene systems present within the region. Although the North Sea Basin is now considered mature, with Cenozoic reservoirs well along their creaming curve (Vining et al. 2005), recent discoveries (e.g. the Catcher Field in 2010) highlight that potential still remains within intensively explored areas such as the Central North Sea, as well as in the less explored regions such as the Atlantic margin and the Norwegian Sea. The importance of these reservoirs is demonstrated by the large proportion of UK production to which they contribute, amounting to approximately 25% of all production from UK oil fields since 1975 on a barrel of oil equivalent (BOE) basis (Fig. 2). Indeed, over time that proportion has increased from 20% of production in the 1970s and 1980s to 30% from the 1990s. ... This 250-word extract was created in the absence of an abstract.

Description: A seismic stratigraphic analysis constrained by well and wireline log data has been undertaken on the Paleocene and earliest Eocene succession of the South Buchan Graben (Quadrants 20 and 21), Outer Moray Firth Basin (OMFB). Two principal sequences have been described relating to two regressive/transgressive second-order cycles of relative sea-level change. The Maureen, Andrew, Glamis Tuff and Balmoral sandstone members are expressed as a stacked set of lowstand basin floor fans separated by mudstone intervals representing four cycles of third-order relative sea-level change. The Sele and Balder formations contain both basinal and shelfal packages as an expression of two cycles of third-order relative sea-level change. The Forties Sandstone Member is deposited within highly mounded, levee-confined channels downlapped by a prograding slope succession with well-defined clinoforms and deltaic topsets attributed to the Dornoch and Beauly formations. The individual parasequences of the prograding wedge are related to higher-order eustatic fluctuations with incision and slope fans, attributed to the Cromarty Sandstone Member, deposited during periods of relative sea-level lowstand. It is demonstrated that through the integration of lithostratigraphic, seismic geomorphological and sequence stratigraphic analyses an understanding of depositional environments and the distribution of facies within them can be obtained. The identification of basinal and slope features with reservoir potential, along with an understanding of their chronostratigraphic relationship to sealing facies, play an important role in regional play fairway mapping and risk analysis in this area and beyond. Future prospectivity within mature basins, such as the OMFB, relies on subtle stratigraphic traps typical of lowstand systems tracts, where the main risk is associated with reservoir quality and containment.

Description: The Triassic Fundy rift basin in Nova Scotia is a large (〉70 km wide) half-graben filled with alluvial, lacustrine and aeolian deposits. A major lithospheric lineament, the Cobequid–Chedabucto Fault Zone (CCFZ), which forms the tip of the Newfoundland–Gibraltar Fault Zone, occurs within the Fundy Basin. The timing of early movement on this important fault zone is poorly constrained. We present data from the alluvial and aeolian units that crop out adjacent to the CCFZ in the Minas sub-basin to determine the initiation of fault movement. We use the onset of alluvial fan deposition to infer when the fault became sufficiently active to create the intrabasinal topography and document the influence of fault activity on the intrabasinal drainage. The occurrence and preservation of aeolian deposits immediately adjacent to the CCFZ and concomitant with alluvial fan development suggests a wind shadow effect associated with the fault-generated topography. The onset of alluvial fan deposition associated directly with the fault occurred during Norian times, following an earlier phase of sedimentation in the Fundy Basin, and records a potentially important phase of plate reorganization during early Atlantic rifting.