Natural oil seeps have historically provided invaluable information to oil explorers in frontier deep and ultra-deep onshore and offshore areas. Foremost, they indicate the presence of active generative hydrocarbon source rocks, without which there can be no hydrocarbon accumulations. In addition, analysis of oil seep samples recovered using Piston Core technology provides clues regarding hydrocarbon origin and type, as well as the thermal evolution of the putative source rocks. More recently, the application of Advanced Geochemistry Technology (AGT) has allowed identification and characterization of oil mixing, the extension of oil cracking to gas and the quantification of hydrocarbon accumulations in the subsurface. The application of AGT is especially important for the detection of micro-seepage. The high cost of offshore deep and ultra-deep exploration has made the identification of oil seeps on the seafloor an accepted risk assessment tool for offshore basins all around the world.