Abstract The Amin Field is a large (120 km) structure that contains 181MM mSTOIIP with an ultimate recovery of 18.4 MM m. The field produces under strong bottom water drive, has dense and viscous crude and thin oil columns. Owing to the relatively poor production behaviour (rates from horizontal wells vary from <10m/d to 200m/d)this field retained unit technical costs which made it uneconomic to develop. However, owing to its large STOIIP, appraisal drilling coupled with integrated studies of this strategic asset have been undertaken in order to improve its development economics. Organic geochemical analysis of well head samples showed the field to contain crudes with a markedly different degree of biodegradation, related to the timing of charge and proximity to the oil water contact. These data, combined with petrographic analyses of cores and side wall samplesdemonstrated a link between diagenesis, reservoir quality and hydrocarboncharge history. Seismic backstripping of the Amin Field highlighted areas of early closure that correspond to areas of good reservoir quality and high productivity wells. In other areas, where oil fill occurred later, enhanced diagenetic alteration of the sandstones resulted in the formation of smectitic clays that have severely reduced the reservoir quality and consequently well productivity. Collation of oil quality data has shown the field to be density/viscosity stratified, and oil quality maps, combined with reservoir quality maps from seismic backstripping, have been produced to allow the most profitable areas to be targetted. By a combination of appraisal drilling and integrated study work, UTCs of the Amin Field have been reduced by 50%, and full development of this major asset is now ongoing.