This volume explores three super-mature oil fields with a view to locating unproduced oil. Recognising by-passed or unswept oil and identifying yet undiscovered accumulations is fundamental to continued production out of super mature oil fields. Reserves were appraised through the cross-field integration and analysis of various data sets leading to a more detailed understanding of reservoir characteristics. The study identified new prospects in a field which was previously thought to be exhausted. In the case of Tengiz/Awali, the field’s structural heterogeneity appears to have compartmentalised the reservoirs and significantly influenced oil production. The identification and accurate delineation of previously undetected faults led to the discovery of potentially unswept reservoir compartments. The 2D seismic study of the Marlim field led to the identification of two rollover closure structures. In proven oil producing provinces such as these, such structures are high value targets. Finally, in the case of Yibal, 3D seismic data allowed the interpretation of oil producing Omega Grit’s lateral extent and the identification of two likely oil bearing anticlinal features.