Heimdal Sandstones within the PL203 Area, Norwegian North Sea core displays

well, seismic and fluid response. The cored interval traversed the gas and oil legs, in what appeared from the electronic logs to be a dominantly massive sandstone succession. Unfortunately, from the e-logs, the oil leg appeared to be developed within a fine-grained interval. From core description and interpretation, facies within the T57 sequence comprised a linked suite of high-density sandy turbidites/debrites (Facies T1) interbedded with low density turbidites (Facies T2). These units were deposited within a linear fairway, the edges of which were controlled by the depositional topography associated with the previous T55 sequence. Although linear and focused, no true channel facies were developed, with the fairway being more depositional than bypass dominated. This interpretation is key in understanding the lateral persistence of the finer grained interval within the oil leg. It is thought that these units are not persistent sheets but spatially restricted lenses, and as such will not prove to have a major affect on volumetrics or reservoir performance.