Hydrocarbon geological aspects of subsidence curves: interpretations based on released wells in the Danish Central Graben

Abstract

The lithostratigraphy of the Danish Central Graben sequence is briefly outlined and the lithostratigraphic subdivision tabulated for 23 released wells. A simple subsidence model for the periode from Triassic to Recent is established exclusively with reference to the presented well data. The model points to pro-nounced changes in the rate of subsidence through Mesozoic and Cenozoic times with major changes taking place during late Jurassic and late Neogene. Based on the subsidence model it is suggested, that possible sourcerocks of Carboniferous or older ages were mature by late Cretaceous time. The presum­ably most promising sourcerock of the Central Graben, the upper Jurassic J-4 unit, reached the hydro­carbon generating level during early Tertiary in the deeper parts of the Graben whereas extensive hydro­carbon generation in the shallower parts did not reach a maximum before Neogene according to the present model.