Chemostratigraphy of the Upper Carboniferous Schooner Formation, southern North Sea

Abstract

Summary The virtually barren, mainly redbed sequences of the Schooner Formation (Upper Carboniferous) of the southern North Sea are an important gas reservoir, although well placement and reservoir development are hampered by the lack of a reliable stratigraphical framework. Chemostratigraphy has enabled the Schooner Formation encountered in well 44/21-3 to be divided into three chemostratigraphical units (S1, S2 and S3) and eleven sub-units (S1a–f, S2a–b and S3a–c), based on variations in mudstone and sandstone geochemical data acquired from core samples and cuttings. The geochemical characteristics of the units can be related to variations in mineralogy, depositional environment, climate and provenance. The units are correlated subregionally and the correlation is used to corroborate seismic correlations. A high-resolution chemostratigraphical zonation and correlation based on sub-units redefines models of reservoir architecture and enhances reservoir development in the nearby Schooner field.