RESERVOIR CHARACTERIZATION OF A SHALLOW MARINE SANDSTONE - THE LOWER CRETACEOUS SANDRINGHAM SANDS (LEZIATE BEDS) AND CARSTONE FORMATIONS, EASTERN ENGLAND

An onshore shallow marine sandbody has been investigated in several ex tensive quarry outcrops in the Norfolk; area of eastern England in ter ms of its sedimentology (sedimentary structures, geometry and architec ture), sequence stratigraphy and reservoir-scale heterogeneity. In add ition to conventional sedimentological logging techniques, vertical pr ofiles were analysed using a steady-state electronic probe permeameter to investigate permeability heterogeneity. Permeability analysis was also complemented by spectral gamma ray profiles, which were used to c haracterize facies associations in terms of their total radioactivity and relative proportions of potassium, uranium and thorium. It was fou nd that lithofacies type and bounding surface have the dominant contro l on permeability heterogeneity and thus flow unit compartmentalizatio n. This study aims to complement pre-existing outcrop analogue dataset s which attempt to model fluid flow more accurately in analogous subsu rface reservoirs. It also serves to highlight the difficulty in accura tely identifying and modelling subsurface shallow marine/estuarine tid al channel depositional systems for well/drainage and/or production st rategies.