The subtle play-potential of Upper Jurassic-Lower Cretaceous block-faultedturbidites in the Danish Central Graben, North Sea

The Gertrud Graben, in the Danish Central Graben, was formed during the Ear ly Volgian by extensional block rotation. The basin was bounded by series o f NW-SE trending normal faults, the resultant bathymetry of which controlle d the depocenters of Volgian-Ryazanian turbidites in the Farsund Formation. Seismic correlation to basin marginal locations in the Jeppe-1 and Gwen-2 wells suggests that high amplitude horizons and high acoustic impedance val ues in the depocenters of the turbidites probably reflect accumulation of s and-rich turbidites. The high amplitude and impedance values, calculated fr om seismic inversion, are locally concentrated below minor closures. A shor t horizontal impedance horizon within the turbidite depocenter and below a closure possibly indicates hydrocarbon accumulation, adjacent to a well-kno wn Jurassic source-rock the 'Hot Unit' (Bo member) in the Central Graben ar ea. The turbidites seem to have been transported mainly from the north, pos sibly from positive areas in the southern Norwegian Central Graben area. Su bsequent Late Ryazanian block faulting and local compressional tectonics ca used erosional truncation of upper parts of the turbidites on footwall bloc ks, but preserved parts of the basin-axial turbidites from erosion in the h angingwall positions. (C) 2000 Elsevier Science Ltd. All rights reserved.