The Logger oil Field (Netherlands offshore): reservoir architecture and heterogeneity

Abstract

The Logger Field is a small oil field (51 million barrels oil in place) located in Block L16a in the Dutch offshore. The oil is trapped in a complexly faulted, overthrust anticline. The producing reservoir is the Lower Cretaceous Vlieland Sandstone. In the Logger Field, this is a thin (10 to 30 m thick) barrier sand with horizontal permeabilities in the order of hundreds of millidarcies to a few darcies. A reservoir geological study, aimed at providing the input for a reservoir simulation model, showed that, contrary to earlier interpretations, the reservoir is strongly layered. Layering reflects stacked, shoaling-upwards and deepening-upwards sequences. The presence of carbonate concretions and cemented layers causes additional vertical heterogeneity within the individual layers. The more detailed description of the reservoir in the reservoir simulation model gave rise to a better history match and hence to more confidence in production predictions.