Rembrandt and Vermeer Oil Fields, Dutch Offshore Block F17-The Impact of Grains on Maastrichtian Chalk Reservoir Quality

Summary In the Rembrandt and Vermeer Fields, a rapid decrease of porosity within the 40–50m thick Maastrichtian Chalk reservoir can be observed. The porosity decreases from around 37% at the top of the reservoir to 22% at the base of Chalk. The cause of this decrease is seen to be the admixture of grains to the chalk mud matrix. Siliciclastic and skeletal grains are non-net elements in the microporous chalk mud matrix. Comparison with other wells show that these porosity trends in the Chalk can be described by a set of equations capturing both the normal depth compaction and the increased admixture of grains with stratigraphic depth. The equations were used to create a predictive model of the porosity which was co-kriged with the well porosity logs in the static reservoir model.