Syn-sedimentary faulitng and the formation of localized reservor sands:Carboniferous examples from the Campine Basin,Beglium and the Dutch offshore

摘要

The Westphalian B in the Campine Basin in Belgium contains a low net-to-gross succession of fluvial chanel and crevasse sandbodies embedded in lactustrine and floodplain claystone and siltstone.Study and correlation of closely spaced boreholes reveals a localized 15-25 m thick succession of stacked fluvial channel sandbodies in this overall low net-to-gross setting.This concentration of sandbodies is interpreted as the fill of a tectionically induced palaeo-valley based on the orientation of syn-seidmentary faults and the palaeogeographical setting of the Campine Basin,far away from the Westphaian sea.The depositional model was used to interpret stacks of fluvial sandstone of the Caister Sandstone (Westplain B) in the Dutch offshore and may guide finding economic reservoirs in the overall low net-to-gross labyrinth-type fluvial architecture in this area and in comparable structural settings.