Probing the lower limits of a fairway: further pre-Permian potential in the southern North Sea

Abstract

Abstract Although the southern North Sea has become a major centre of hydrocarbon production, the lower limit of the fairway has not been established. We show, using a review of the pre-Permian source-rock potential of the southern North Sea, that the regional geology will permit exploration below the present base of the fairway. Seismic mapping indicates that this portion of the stratigraphic column is associated with multiple objectives. Two very different examples demonstrate the range of opportunities. The first example is a conventional structural trap located on the northeast flank of the London-Brabant Ridge in Quadrant 53. Reservoirs are the Westphalian to Devonian succession. Source-rocks are lacustrine horizons within the local Westphalian succession and the Carboniferous to Devonian section to the northeast of the South Hewett Fault. The second example presents a new objective, a stratigraphic trap to the ESE of a high located in Quadrants 42 and 43 and identified for the first time by this study. The anticipated reservoir is Dinantian carbonate progradational wedge derived from the adjacent high. Namurian and Dinantian source-rocks are predicted. Until opportunities of these types are evaluated, the lower limit of the Southern North Sea fairway will remain undefined and ultimate reserves estimates will continue to be poorly constrained.