An integrated project was initiated to re-evaluate the Heather Field, in the UK North Sea. The project involved the facies description of core material, a study of the diagenetic history of important rock units, a structural reinterpretation of the field area, and an investigation of the petroleum generation and fluids migration. The sedimentary section grades upward from shallow shelf turbidites and fan deltas to major fluvial-deltaic systems, with delta-front/shoreface sediments, and finally delta plain and tidal flat facies. The diagenetic history is very complex, and includes K-feldspar overgrowths, and kaolinite, calcite, quartz and illite cements. A geochemical source rock study indicates that petroleum generation began in late Cretaceous and that there were two petroleum generation areas.